General Info
Radiology department diagnoses many diseases with the help of various medical devices. Devices used in radiology department;
A.DEVICES THAT USES X-RAY (MAY BE HAZARDOUS IN PREGNANCY)
1. X-Ray
a.This device is most commonly used to diagnose bone and lung diseases.
b.X-ray is used.
2. Mammography
a.It is often used to diagnose breast diseases.
b.It is also preferred as screening device for patients older than 40.
c.X-ray is used.
3. Bone Densitometry
a.It is usually to diagnose osteoporosis. It measures the bone density.
b.X-ray is used.
4. Computerized Tomography (CT),
a.It is used to diagnose diseases in the total body.
b.Cross-sectional images of the body are acquired.
c.X-ray is used.
5. Angiography = DSA = Digital subtraction angiography = Catheter angiography
a.It is used to diagnose vascular diseases.
b.Angiography device is also used to treat vascular diseases.
c.Various equipment is used to access lumen of blood vessels; and they are imaged by infusing a dye into the vessel.
d.X-ray is used.
B.DEVICES THAT USE SOUND WAVES
1. Ultrasound
a.This medical device is most commonly used to diagnose diseases of intra-abdominal organs.
b.It is used to supervise pregnancy; it has no hazard.
2. Color Doppler Ultrasound
a.It is used to diagnose vascular diseases.
b.Blood supply to many organs is also evaluated.
c.It is also used in pregnancy.
C.DEVICES THAT USES RADIOFREQUENCY WAVES
1. MRI (Magnetic Resonance Imaging)
a.It is used to diagnose diseases of brain and muscles – ligament in all body structures.
b.In addition, it is commonly used to check abdominal organs.
c.MRI angiography is often used to visualize vascular diseases.
d.It may be contraindicated, if there is a foreign body in the body.
COMPUTERIZED TOMOGRAPHY (CT) AND TECHNICAL DATA
Computerized tomography is a radiological diagnostic method that provides cross-sectional (anterior to posterior = coronal; superior to inferior = axial; right to left = sagittal) images of the intended part of the body using x-rays. While images are acquired, patient lies immobile on the table of computerized tomography device. The table is inserted into an empty space, called “gantry", either manually or with a remote control. The device is connected to a computer. While the X-ray source rotates around the patient by 360 degrees, detectors placed in the hole or the “gantry" identify the part of X-ray beam which passes through the body, and the resultant data is processed by a computer. Ultimately, successive cross-sectional images of tissues are created. Created images can be displayed on the monitor of a computer. Moreover, images can be printed on films or stored in the optic disc in order to re-display on the monitor of a computer, if or whenever necessary. Computerized tomography has several advantages over other X-ray imaging systems. Shape and location of organs, soft tissues and bones are especially visualized very clearly. Moreover, computerized tomography scan helps doctors make differential diagnosis of a simple cyst (a formation filled in by fluid or semi-liquid substance and surrounded by a wall) and solid tumor (a lump caused by abnormally quick division of cells) and thus, diseases are better evaluated. More importantly, computerized tomography assists staging of the cancer by creating much more detailed images relative to direct roentgenogram. Information about the stage of cancer assists the doctors when deciding the treatment for cancer, such as chemotherapy, radiotherapy, surgical intervention or combinations thereof. Thus, healthy tissues are protected against unnecessary adverse effects of this treatment, which have substantially beneficial effects in combination with serious side effects. Computerized tomography can image many body parts, such as brain, that cannot be visualized with direct roentgenograms. Moreover, this method enables earlier and accurate diagnosis of the disease comparing to other imaging modalities. Since diseases are better treated when they are diagnosed early, computerized tomography with such superior features help doctors save many lives.
DOES THIS SCAN CAUSE DISCOMFORT? IS THERE ANY HAZARD?
The scan itself is completely pain-free. While images are acquired, patient is asked to lie constantly immobile on the table of computerized tomography device. Depending on the type of examination, either the contrast agent is injected into a vein of arm or taken by the patient by mouth. This part of examination may be somewhat annoying for the patient. Since contrast agents contain iodine, they may lead to allergic reactions in some patients. The patient should notify the technician or radiologist in advance the past history of allergic reaction to such substances or any other substance. The patient might have been given contrast agent in a previous CT, a renal examination called IVP or a catheterization, also called angiography of heart and vessels. CT devices use X-rays. It is designed to maximize safety of patients and it is manufactured to minimize the dose of radiation exposed in the scan. Since X-rays may damage the fetus in the intrauterine life, the patients with proven or potential damage should notify the doctor or technician before preparations for the examination are started.
WHAT SHOULD BE DONE TO GET PREPARED FOR EXAMINATION?
DAY OF EXAMINATION
No solid food should be ate, starting 4 hours to the appointment hour, in the day of examination. However, coffee, tea, grain-free soups and fruit juice are allowed in low amounts. Restricted solid food intake is a measure taken to ensure safety of patients before many medical procedures.
EXAMINATION ROOM
You should be ready at the hospital at least 15 minutes before your appointment. This will provide you the time to complete recording procedures at the hospital. If computerized tomography of abdomen or pelvis will be scanned, you should beat the hospital 1 hour and 15 minutes before the appointment hour. The patient is asked to drink contrast agent solution that images the digestive system more clearly and enables the radiologist review the films better. Depending on provisional diagnoses and the examination requested, patients may also be asked to drink the contrast agent solution far before the appointment hour. CT technician will introduce himself and inform the patient about the procedure and helps the patient relax by answering potential questions. Patients may be asked not to have metal objects in body depending on the body part to be scanned. Next, the patient is worn a gown.
WHAT HAPPENS IN THE SCAN?
Technician guides the patient to the examination room and makes the patient lie supine or prone depending on the examination. It is very important to make patient feel comfortable, as the patient should not move throughout the scan. Ct scans may vary depending on medical problems of patients and the body parts to be imaged. Radiologist will decide how the scan will be performed to diagnose the disease. For example, the lower part of chest to upper part of pelvis is scanned if CT of abdomen is scanned. In this examination, you will be asked to hold your breath at certain intervals to avoid blurred images. The machine will strange some sounds throughout the scan. The table, where the patient lies on, will slightly move, after each image is acquired. Moreover, technical or machine will send a signal to the patient to instruct breath holding. For certain examinations, the doctor or technician may inject a contrast agent before or during the scan. This will help the radiologist review images better. If the patient feels something unusual during or after the injection, the technician or doctor should be notified. All CT personnel are educated to render the best service for patient and they have necessary certificates in this field.
HOW LONG DOES COMPUTERIZED TOMOGRAPHY LAST?
Examinations are planned separately for each patient by taking into consideration the clinical signs. Therefore, patients should not get anxious, if the current CT scan differs from the previous CT scan or it is necessary to acquire extra images. The entire scan lasts 15 minutes in average.
WHAT SHOULD BE DONE AFTER THE SCAN IS COMPLETED?
After the radiologist gets sufficient details to draw a conclusion about the disease, the scan is terminated and the patient is allowed to go home. Patients may engage in activities of daily life without any restriction after the radiology study.
HOW ARE IMAGES EXAMINED?
The images are reviewed by radiologists who are specialized the intended body part and next, findings are written on a report that is delivered to the patient. Please ask any other questions to doctors and technicians who will carry out your examination. They will be so happy to help you by informing you about how the examination is performed.
COMMON INTENDED USES OF CT
CT imaging for Otolaryngologic Conditions: As is the case with other departments, CT is commonly requested by otolaryngologists. The most common conditions are as follows:
Diseases of Paranasal Sinuses, Nose and Nasal Cavity: Computerized tomography is the most useful imaging modality for any and all sinus diseases, especially chronic sinusitis, and hypertrophic nasal turbinate as well as tumors. Paranasal sinuses have a complex structure and physical examination provides an insight to a certain extent. However, CT demonstrates anatomic structure of all paranasal sinuses, their orifices draining into the nasal cavity, hypertrohic nasal turbinate and tumors in a very detailed manner. When CT is scanned to examine sinusitis, it is not necessary to use contrast agents or media, but they might be required for tumors.
Diseases of Middle and Inner Ear: It provides information about the spread of chronic inflammation in the middle ear, the loss of bone in ossicles of middle ear and other middle ear structures. CT scan will be useful especially if a surgery is considered for chronic middle ear inflammations. Certain types of hearing loss suggest tumors or similar diseases in the middle ear. In such cases, magnetic resonance imaging is scanned, but CT is, sometimes, required, if it is more useful for the patient.
Mass lesions in neck: Identification or definitive diagnosis of lumps or growths in neck is one of the most significant challenges faced by otolaryngologists. CT provides very important information about such conditions or even, it might, sometimes, help the diagnosis.
Tumors or Other Diseases of Pharynx, Esophagus and Larynx: Since CT creates cross-sectional images, details about spread of tumors or other diseases in these anatomic structures are obtained and the surgery is planned accordingly.
COMPUTERIZED TOMOGRAPHY (CT) AND TYPES
CONVENTIONAL COMPUTERIZED TOMOGRAPHY
Computerized tomography scanner is equipped with a tube that generates X-rays and detectors that sense those rays. The patient lies between these components. Thus, X-rays enter and pass through the body and are picked up by detectors. Since atomic densities of body tissues vary, absorption of X-ray will vary in each tissue and thus, tissue images are created. The tube and detectors turn around the patient by 360 degrees and cross-sectional images of the body are acquired. After a cross-section image is acquired in conventional computerized tomography, the table moves forward and the next cross-sectional image is acquired. This modality is not only time-consuming, but it is also very sensitive to respiratory movements; and therefore, it is not appropriate for cardiovascular studies.
SPIRAL COMPUTERIZED TOMOGRAPHY
Recently, spiral computerized tomography scanners (Spiral CT) are developed to cope with this difficulty. In this modality, tubes and detectors constantly turn around the patient, while the table, where the patient is positioned on, moves continuously in a pre-determined velocity (Picture 2). Since the movement follows a spiral route relative to the patient, it is called Spiral CT. This technique shortened the examinations very substantially. However, it did not help scan a moving organ, i.e. heart.
MULTI-SLICE COMPUTERIZED TOMOGRAPHY
Next, multi-slice spiral CTs (MS CT) are developed to overcome this difficulty (Picture 3). In this type of scanners, thinner detectors are configured in more than one row. The recent technological advancements also accelerated the movement of tube. The detectors that were configured in 4 rows in the patient are designed in 16 rows in subsequent generations and 64 rows in the last-generation scanners. Thus, resolution of images is improved and images can be acquired while the patient holds breath for less than 20 seconds.
ADVANTAGES OF MULTI-SLICE COMPUTERIZED TOMOGRAPHY
• It is non-laborious diagnostic method that provides information about vascular diseases.
• The scan is completed in a short time and images can be acquired in a short breath-holding interval.
DISADVANTAGES OF MULTI-SLICE COMPUTERIZED TOMOGRAPHY
The diagnostic value is low in arrhythmic patients (especially atrial fibrillation).
• The patient needs to hold breath approximately for 20 seconds. However, this interval is shortened in 64-slice scanners.
• It cannot be used in patients who should not be exposed to radiation (pregnancy etc.).
• Diagnostic value decreases in high heart rates (above 70 beats per minute) and therefore, it is necessary to decrease the heart rate.
• Diagnostic value decreases if dense formations (calcium, stent, clips etc.) are present in coronary arteries.
• The radiation dose exposed by the patient is not less than the conventional angiography.
• As is the case with conventional angiography, contrast agent (opaque dye) is administered. Therefore, attention is required for patients who are allergic to these agents or have contraindications (such as renal failure).
DOPPLER ULTRASOUND SCANNER AND TECHNICAL DATA
COLOR DOPPLER ULTRASOUND
This method is based on the fact that the frequency of sound changes while it echoes from moving structures and it is used to evaluate the flow in vascular structures. When the flow data is colored according to the direction of flow relative to the transducer and the velocity of flow and inserted into the image of blood vessel on a gray scale, also called B Mode, color Doppler image is acquired. Velocity of flow is measured and flow patterns are determined using the Doppler spectrum in the form of graphics. (Australian physicist and mathematician Christian Doppler). The moving objects targeted by Doppler runs are red blood cells.
WHICH EXAMINATIONS ARE MADE WITH DOPPLER ULTRASOUND?
It is used to evaluate arterial and venous structures (for example, arteries of the neck – carotid and vertebral arteries; arteries and veins of arms and legs; real arteries; hepatic and portal system etc.); varicocele in scrotum; vascularization in tumors and inflammatory formations in superficial structures, such as breasts, testicles, parathyroid gland, lymph nodes and soft tissues as well as parenchymal organs. It can visualize occlusions in vascular structures, venous valve insufficiency and renal artery stenosis. Doppler examination of umbilical artery and fetal organs following 20th week of pregnancy provides details about whether there is growth retardation or fetal distress in fetus or not. For gynecological tumors, transvaginal Doppler informs physicians about whether the tumor is benign or malignant. It generates details about ectopic pregnancy and ovarian distortion. Perfusion of the transplant organs can be evaluated. Logic 7 is a top-level, premium sonography device. Coding technology is used for B-flow and Color-Power Doppler sonograms. This technology increases sensitivity substantially, eliminates unwanted signal components and thus maximizes the image quality. The “Coded Harmonic" feature creates more detailed images with better contrast resolution by using high frequencies.
Automated tissue optimization acquires best images with highest quality in B-Mode and Doppler runs. LCD color touch screen facilitates access to setup and control menus. The feature of “virtual convex" creates a convex area, when linear probe is used. Thus, precise measurements can be made by fitting the entire image into the same area.
Matrix Linear Probe (M12L) enables examination at range of 7, 10, 12 and 14 MHz and thus, optimal images are acquired especially while breast, thyroid gland, testicles, superficial tissues and vascular structures are imaged. E8C and 3.5C probes have multi-frequency feature that allows a broad range of applications. It is also characterized by raw data, archiving and post-process measurement and analysis. Integrated DVD writer and large hard-disc image archiving capacity allows reporting and archiving.
What you should take care of while presenting for Doppler Ultrasound?
An appointment should be scheduled and you need to learn necessary preparations, if any, according to type of examination. For example, medicines that discharge intestinal gas are used for 3 days and you should stop eating and drinking 12 hours before you present for Renal Artery Doppler Ultrasound. Wear comfortable clothes when you come for the examination. Bring the request form written by your doctor and your previous examinations, if any, to help the radiologist establish the diagnosis.
ROLE OF ULTRASOUND IN TRISOMY SCREENING
Ultrasound measures nuchal translucency of fetus for first-trimester screening test. Week 11 to 14 pregnancies with crown-rump length ranging from 45 mm to 82 mm are examined. An ultrasound scan measures CRL and nuchal translucency. Doppler ultrasound evaluates fetal heart, umbilical cord and ductus venosus. Nasal bone, fetal cranium, vertebral column, stomach, abdominal wall and extremities are imaged and evaluated.
Following an ultrasound scan, blood is drawn from the pregnant women and serum PAPP-A and Beta HCG are analyzed. All these tests are reviewed in a software specific for this test that is supplied by FMF (Fetal Medicine Foundation) and the odds of fetal chromosomal anomaly are estimated.
TYPES OF DOPPLER
The blood flow in vessels can be in two configurations in the sonogram. In the first one, vessels are color coded on the ordinary ultrasound image (Color Doppler); and in the second one, the flow is displayed in a graphic form other than the usual sonogram (Spectral Doppler). These graphics are called flow curves and they have unique characteristics for each vessel. In the Color Doppler Mode, the flows towards and against the probe are displayed in red and blue colors on the screen. After the image is acquired and relevant vessel is identified, Spectral Doppler is concomitantly run by focusing on this vessels and mathematical measurements are made for the velocities of blood flow and resistance against the flow in the blood vessel.
Since ultrasound scanners with Doppler feature are extremely expensive relative to conventional devices, they are not available in all centers and therefore, Doppler examinations are often made by a doctor other than the doctor who supervises the pregnancy.
Detailed ultrasound scan that is incorrectly called “color ultrasound" in colloquial term and requires specialized education and experience differs from Doppler scan.
WHY IS DOPPLER SCAN USEFUL?
Since blood enables sustainability of tissue viability by carrying oxygen and nutrients to tissues and waste materials from these tissues, it is important to measure the blood supply to a certain tissue in some conditions in order to learn whether the tissue is sufficiently fed or not.
For example, the ovary cannot be supplied sufficient blood and may be lost due to gangrene in ovarian torsion – a condition characterized by twisting of the ovary around its own axis. In case of a suspicion, ability to identify whether the ovary is supplied blood sufficiently or not with Doppler run may be critically important in the decision of an operation.
On the other hand, cancers cause formation of new vessels in the tissue, a process called neovascularization. Demonstrating the hypervascularization in an ovarian tumor with a Doppler run may provide valuable tips on whether the pathology is benign or malignant.
Considering supervision of pregnancy, Doppler scan plays an important role to determine risks for certain diseases and conditions. The resistance in blood vessels that feed the womb decreases in pregnancy under normal circumstances and therefore, the blood flow to uterus and indirectly to placenta and fetus increases. If this resistance does not decrease and the required volume of blood cannot be supplied, notches are observed on Doppler flow curves.
It is suggested that the increased risks for potential future pre-eclampsia, intrauterine fetal growth retardation, early separation of placenta (placental abruption) and intrauterine fetal death can be predicted, when the blood flow and vascular resistance are measured in the uterine artery that feed the womb and in the umbilical artery in Week 20 of the pregnancy with a test, called Doppler screening test. Accordingly, it is recommended that notches observed on Doppler examination of bilateral uterine arteries are deemed a pathology or positive screening test and close follow-up is started. However, a trial that reviewed all studies conducted on this issue revealed out that Doppler screening test is required only for high-risk pregnancies, not all pregnant women. The blood flow curves of the umbilical artery play an important role to determine the volume of blood supplied to the fetus and to evaluate the problem especially in fetus with growth retardation.
Since extremely decreased blood flow may cause intrauterine fetal death in last phases of pregnancy, it is critically important to make the decision of delivery. In addition, Color Doppler can be used to see and hear fetal heart beats in early pregnancy. In the next picture, Doppler examination of fetal heart beats in a 9 weeks and 6 days' pregnancy is seen. Another application is to visualize the great arteries that originate from the fetal heart. Imaging the vascular structures at both sides of the fetal urinary bladder in a routine obstetric ultrasound is a finding that minimizes the risk of a potential anomaly.
HOW IS IT SCANNED?
Doppler ultrasound does not require a separate session. If the ultrasound device used for routine pregnancy supervision has Doppler feature, your doctor may switch to this mode at any time to visualize and measure blood flows. For example, while fetal heart beats are listened in the first ultrasound scan of a 6 weeks' pregnancy, Color Doppler can image the vascular structures at both sides of the fetal urinary bladder in the fetus in a subsequent phase.
In detailed ultrasound scan around Week 20 of the pregnancy, your doctor may measure blood flows in the arteries that feed the uterus, if deemed necessary. In subsequent routine examinations, blood flows are measured in the umbilical cord and the general health of fetus is reviewed.
DOES DOPPLER SCAN POSE RISK?
From theoretical point of view, Doppler ultrasound scan poses higher risk of regional heat increase and aneurysm. Therefore, the risk posed by this examination is slightly higher relative to the ordinary ultrasound scan, albeit again from a theoretical perspective. However, although animal studies show that long-lasting Doppler scan can cause approximately 2.5 ℃ heat increase in tissues, this level is safe even for human and obstetric Doppler scans do not last such long. To date, no adverse effect is reported for Doppler scans of humans.
BONE DENSITOMETER AND TECHNICAL DATA
This study measures the bone density. In other words, it is a measurement method determining the bone fragility. If osteoporosis is diagnosed, this device is also used to follow-up medication therapy to determine the ratio of benefiting from the medication. The measurement takes 1 minute. As the patients do not feel pain in osteoporosis, problems of individuals giving up taking the prescribed medications worsen insidiously. Therefore, osteoporosis is called "the silent disease". Osteoporosis is totally an untreatable disease. However, it is possible to stop it at current level by means of appropriate drug use and modification of life conditions.
SHOULD I HAVE MY BONE DENSITOMETRY MEASURED?
If bone loss starts for any reason whatsoever, they cannot specify the related problems before they experience pain and fractures at advanced ages. Depressions occurring in vertebras are not generally recognized during daily life. Women and men between ages of 20-45 should necessarily have control examination once.
HOW FREQUENTLY SHOULD I HAVE BONE DENSITOMETRY MEASUREMENT?
This totally depends on the degree of density loss in your bones, the therapy you receive and the continuity of special conditions causing bone loss. Your physician will follow you about this issue.
WHAT IS OSTEOPOROSIS?
Osteoporosis is an unavoidable disease which is seen in post-menopause period in women and after 55 years of age in men. It is especially seen in women and frequently in post-menopause period. The reason is the decrease in oestrogen level after menopause.
Osteoporosis is a skeletal disease which causes increase in risk of fracture in bones due to loss in bone mass and deterioration in microscopic structure of bone tissue. Loss of calcium, which is seen in every individual, causes this disease. The lost bones cannot be gained back. However, it can be kept in the current condition if it is diagnosed early. The condition is unavoidable for women due to menopause; however, it can also be seen in young subjects and men for various reasons.
HOW IS BONE STRUCTURE?
As is known, the development of bone structure is closely related to genetic structure of human, acquired diseases, orthopedic prosthesis surgeries, the periods after more than two pregnancies and menopause, gradually sitting more and working immobilized in working environments, avoidance from the direct sun exposure during holidays and daily lives, long-term use of some medications, diabetes, renal, goiter and hormone problems, unbalanced diet with instant and hormone-injected foods especially in young subjects.
Bone is a living tissue like other tissues of our body. It consists of two segments; compact layer and spongy layer.
HOW DOES BONE STRUCTURE CHANGE WITH OSTEOPOROSIS?
Compact (hard) layer of bone gets thinner and spaces in spongy layer grow in early stages. Then, fractures occur in weak bones at advanced ages.
WHAT ARE THE RESULTS OF OSTEOPOROSIS?
When back bones lose their forms, short posture and humpback develop. Hip, wrist/ankle and spine fractures occur even with a minimal trauma.
WHAT ARE SYMPTOMS OF OSTEOPOROSIS?
Generally, no sign or pain is experienced until fractures occur. However, some people may experience bone pains which are considered rheumatism at advanced ages.
When intensive bone loss occurs at advanced ages, complaints like pain, collapsed backbones, shortening in height, humpback, kyphosis, hip, hand and wrist fractures occur. There is nothing to do after this point. Considering that it can be accidently recognized even in x-ray after 45% of bone loss, the importance of bone densitometry device which is the only diagnosis and follow-up option for osteoporosis is understood.
It should be accepted that osteoporosis is not a disease affecting only women and old people, but is a general disease, and it is necessary to diagnose it in osteopenia period at latest. This disease is not specific for any age groups or a gender. It is known that fractures at advanced ages causes excessive financial load for the patient and relatives and also social security system. Therefore, it is a fact that the patients lose their daily life standards and patients who are confined to bed especially because of femoral fractures die early. As the ideal method, everyone should have a control measurement once with “screening method" and understand the condition and have the control measurements yearly –if there is osteoporosis-, two years later -if there is osteopenia- and at the intervals recommended by physician depending on age and gender -if the results are normal-. Bone loss is very quick in patients having renal dialysis due to chemical substances used and those patients should have control examination once in 6 months and receive serious medication support.
The screening method selected as gold standard for bone mineral densitometry is Pencil Beam. Thus, real-time screening is performed point by point without skipping the whole bone tissue, such as all scintigraphies. Fan Beam method which produces the energy with pulse using a lever that screens a wide array, passes the ray through a "compensation beam" and tries to arrange itself continuously. Thus, it always reflects a pulse-type ray. D1 section is a phantom of value, D2 section is a phantom of soft tissue and air is a phantom of air value. This wheel always turns on the ray and tries to arrange itself. Computer becomes a part of activity for mathematical arrangements when there is a voltage or minor mechanical deviation. It always scans twice to be sure. Moreover; the patient and the user receives high radiation due to Fan Beam method which causes dissemination.
BONE MINERAL DENSITOMETRY MEASUREMENT METHODS
Bone mineral density measurements are performed for low bone density and fracture syndrome. This method is used to support or prove the diagnosis of osteoporosis, to determine the degree of osteopenia by means of increased fracture risk as bone density decreases, to decide whether there is need of treatment and to determine the effectiveness of therapy. Ideal densitometric measurement should be quickly applicable and trustworthy, cause low exposure to radiation, has low margin of error, give an idea about risk of fracture, evaluate the bone separately for trabecular and cortical aspects and be used safely for following up the efficiency of treatment.
1. Single Photon Absorptiometry (SPA) is the measurement of the passage of regular mono-energetic photon beam spreading from a I source from an extremity with radiation with a detector determining the radioactive body gleams including Na iodine. This system does not distinguish cortical and trabecular bones. Distal segment of radius is measured and given radiation. SPA does not provide sufficient information on prognosis. It can be utilized for type II osteoporosis characterized with both cortical and trabecular bone loss, patients older than 70 years of age or cases of remarkable spiral deformity for whom spinal measurements cannot give reliable outcomes.
2. Dual Photon Absorptiometry (DPA) is based on measurement of two photon beams with two different energies. Radiation source is Gadalinium 153. Lumbar spine, femur or whole body can be measured. Around 10-15 mrem radiation is received during this measurement which cannot distinguish cortical and trabecular bone and the procedure lasts for 20-40 minutes. Reliability ratio is high. The space between L2-4 levels are measured and the result is stated as g/cm.
3. Dual Energy X-ray Absorptiometry (DEXA) is a relatively new technique comparing to the others; it is performed in a shorter time and results are more certain. X-ray is used instead of radioisotope agent. Lumbar region, femur or whole body can be measured. Radiation doe is 1-3 mrem and sensitivity ratio is high. Density of spreading beam is more than DPA. Therefore, images are obtained more quickly.
WHO ARE INCLUDED IN RISK GROUP OF OSTEROPOROSIS?
• People who do not consume sufficient amount of foods with calcium (milk and dairy products) in daily diet.
• People from each age group who have irregular eating habit.
• Diabetic patients.
• People passing renal stone and people with other renal diseases.
• People who use cortisone drugs, some anti-acid gastric drugs and sedative drugs for a long time.
• People who consume too much tea and coffee, smoke and drink alcohol and consume insufficient amount of milk, yoghurt, cheese etc.
• People with genetic tendency.
• Women with history of more than two childbirths.
• Women in menopause period.
• Women small, thin body structure
• Women with history of more than three deliveries
• People with light colored eyes, light skin and hair tone
• People with sedentary lifestyle
• Men older than 50 years of age are under risk of osteoporosis.
• People who consume red meat
HOW IS OSTEOPOROSIS DIAGNOSED?
Today, even bone losses at low degrees like 1% can be diagnosed with BONE DENSITOMETRY measurements. Osteoporosis is primarily recognized with a proper history and physical examination. In this history; questions such as osteoporosis, some related medical conditions experienced by you and whether you or your relatives have history of fracture. The physician will evaluate your history and ask you to have x-ray scans to determine fracture –if any- and “Bone Densitometry" test to determine bone mineral density following a series of physical examination procedure and tests.
Bone densitometry is a painless procedure such as having x-ray scan. Mineral density of your bones in the targeted region of measurement is determined using x-ray beams and sound waves during the densitometry procedure. The determined values are compared to the values of healthy young adults and a value called T score is obtained; the condition of measured bones comparing to healthy bone measurements is determined.
FEATURES OF BONE DENSITOMETRY DEVICE
The most developed method used in densitometries is bone density measurement using DPX-DEXA (Dual X-ray Absorptiometry). While LUNAR-DPX-DEXA system has the highest accuracy ratio, it can use Turkish standards with approval of World Health Organization (WHO). T-score is stated in result report, risk of fracture is graphically shown according to World Health Organization (WHO), % changes of recurrent measurements are observed and response to therapy is followed.
WHICH CHANGES CAN BE MADE?
LUNAR-DPX-NT bone density (BMD) measurement device is used for AP Spine Femur, Whole Body, Dual Femur, Forearm, Lateral Spine measurements.
It can provide body composition (fat ratio etc.) measurements in a short time with perfect repeatability.
FOR WHOM BONE DENSITOMETRY SHOULD BE PERFORMED?
Bone densitometry test should only be performed by considering the risk factors of the patient and only if the measurement results will help the decision of therapy. If you are already receiving hormone replacement therapy for menopause, bone densitometry might be unnecessary. However, a bone densitometry to be performed before deciding the therapy can provide supportive information in deciding therapy by determining your personal risk status. In addition, bone densitometry measurements to be performed at 18-24 month intervals in the years when you are under treatment will be helpful to follow the response to therapy.
WHAT CAN BE DONE AGAINST DEVELOPMENT OF OSTEOPOROSIS?
Osteoporosis can be prevented with some simple applications which are started from childhood period and maintained for lifetime. The main ones of these are providing sufficient amount of calcium lifelong, preserving regular exercise and sufficient estrogen level in women, testosterone level in men. Having strong bones in childhood and adulthood period is the best support to prevent osteoporosis that might be seen in future. Ensuring sufficient calcium intake and sufficient general nutrition is extremely important in these periods.
Walking, exercises and regular exercises in this period are important to achieve bone mass. Young people should avoid from harmful habits such as smoking, extremely lean body and alcohol consumption. Peak bone mass is provided at 20s and shows a minimal decrease during the following 20 years. If there are low calcium and vitamin D in person's diet, excessive consumption of cigarettes and alcohol, sedentary lifestyle or use of medications affecting bone metabolism, the level of loss will be more than expected and this will cause risk for the future. Bone loss increases at more advanced ages. Accelerated bone loss is observed in women starting from 40 years of age while it occurs at later ages in men and it is not as quick as in women.
Elder people may benefit from sufficient daily calcium and vitamin D intake. Regular physical activity is necessary in this period to preserve muscle tone, joint mobility and bone health.
INDICATIONS OF BONE DENSITY MEASUREMENT FOR PEDIATRICIANS (5-20 YEARS OF AGE)
• Juvenile osteoporosis (Idiopathic)
• Cushing syndrome
• Hypophosphatasia, osteogenesis imperfecta
• Cortisone therapy
• Monitoring osteoporosis therapy
• Cystic fibrosis
• Leukemia
• Juvenile rheumatoid arthritis
• Shortening in length thoracic kyphosis
• Osteoporosis (positive findings)
• Diabetes Mellitus
• Deficiency of growth hormone
• Chronic diseases (Congenital heart disease, chronic liver disease, chronic renal failure and dialysis)
• Risk Factors: Staying away from sunlight, Malnutrition (protein and calorie deficiency), Immobilization
INDICATIONS OF BONE MINERAL DENSITY MEASUREMENT FOR GYNECOLOGISTS AND OBSTETRICIANS
• Osteoporosis (positive findings)
• Menopause
• Surgical menopause
• Multiple deliveries
• History of hip fracture in mother and grandmother
• Cortisone therapy (<7.5 mg/day >1 year)
• Monitoring osteoporosis therapy
• Estrogen deficiency (*Premature menopause (<45 years)
• Long-term secondary amenorrhea (>1 year)
• Primary hypogonadism
• Shortening of length thoracic kyphosis (History of fragility fracture hip, vertebra, forearm)
• Radiological evidence for osteopenia or vertebral deformity *Low body mass index (<10 kg/m2)
• Body mass index=body weight (kg)/height (square meter)
• Risk Factors: Small body structure (<160 cm, >50 kg), long-term immobilization (more than 1 month), inactivity, excessive smoking, alcohol use
INDICATIONS OF BONE DENSITY MEASUREMENT FOR PHYSIOTHERAPISTS:
• Rheumatoid arthriditis and rheumatoid spondylitis (more than 5 years) Post-menopause
• History of hip fracture in mother and grandmother
• Cortisone therapy (<7.5 mg/day >1 year)
• Monitoring osteoporosis therapy
• Shortening in length thoracic kyphosis
• Osteoporosis (positive findings)
• History of fragility fracture hip, vertebra, forearm
• Radiological evidence for osteopenia or vertebral deformity
Low body mass index (<19 kg/m2) Body mass index =body weight (kg)/height (square meter)
• Risk Factors: Small body structure (<160 cm, >50 kg), long-term immobilization (more than 1 month), inactivity, excessive smoking, alcohol use
INDICATIONS OF BONE DENSITY MEASUREMENT FOR INTERNISTS:
• Hyperthyroidism, hyperparathyroidism, diabetes
• Post-menopause
• History of hip fracture in mother and grandmother
• Cortisone therapy
*Leukemia, lymphoma, chemotherapy, radiotherapy
• Cortisone therapy (<7.5 mg/day >1 year)
•Monitoring osteoporosis therapy malabsorption, hepatic failure, renal failure *History of fragility fracture hip, vertebra, forearm
• Radiological evidence for osteopenia or vertebral deformity
•Low body mass index (<19 kg/m2)
• Risk Factors: Small body structure, long-term immobilization (more than 1 month), inactivity, excessive smoking, alcohol use
INDICATIONS OF BONE DENSITY MEASUREMENT FOR ORTHOPAEDISTS:
• Prosthesis and implant follow-up
• Post-menopause
• History of hip fracture in mother and grandmother
• Cortisone therapy (<7.5 mg/day >1 year)
• Monitoring osteoporosis therapy
•Bone tumors, bone metastases
• Osteoporosis (positive findings)
• Shortening in length thoracic kyphosis
• History of fragility fracture hip, vertebra, forearm
• Radiological evidence for osteopenia or vertebral deformity
•Low body mass index
INDICATIONS OF BONE DENSITY MEASUREMENT FOR RADIOLOGISTS:
• Osteoporosis (positive findings)
• Monitoring osteoporosis therapy
• Shortening in length thoracic kyphosis
• History of hip fracture in mother and grandmother
• History of fragility fracture hip, vertebra, forearm
• Radiological evidence for osteopenia or vertebral deformity
•Low body mass index
•Menopause, post-menopause, surgical menopause
•Estrogen deficiency, multiple deliveries
•Bone tumors, bone metastases
• Prosthesis and implant follow-up
•Ankylosing spondilitis (persisting for more than 5 years)
• Cortisone therapy
• Juvenile osteoporosis (Idiopathic)
• Juvenile rheumatoid arthritis
• Cushing syndrome, leukemia, diabetes, cystic fibrosis, growth hormone deficiency)
• Chronic diseases (congenital heart disease, chronic hepatic disease, chronic renal failure and dialysis, hyperthyroidism, hyperparathyroidism, diabetes, leukemia, lymphoma, chemotherapy, radiotherapy, hypophosphatasia, osteogenesis imperfecta, malabsorption, hepatic failure.) Clinical findings for bone mineral density measurement indications stated above are almost the same and as listed below;
• Back pain,
• shortening of length
• Spinal deformity,
• Osteoporotic fractures.
MAGNETIC RESONANCE IMAGING (MRI)
This pain-free technique enables visualizing and examining body parts by vibrating the hydrogen atom in body with radio waves in a very strong magnetic field and the technique does not use hazardous X-ray and does not require contrast agent that may cause allergy. In a room isolated for this purpose, the patient stays immobile on a table that is located in a very strong, tunnel-like magnetic field. You need to lie immobile on the table and breathe calmly in an MRI scan. You may be asked to hold your breath for a shot time in some examinations. There are two types of MRI .
1) Closed Form: It has a very strong magnet.
2) Open Form: It has a magnet with low power. The only advantage is about the patients with claustrophia.
You will need to remove all removable metallic objects (belt, hair clip, jewelry, coils, keys and dental prosthesis (iron, steel)) before you enter the MRI room. The magnet interferes with magnetic cards, such as credit card, CD and tape band, and makes them unusable. MRI scan is contraindicated for patients with pacemakers, cochlear implants and clips in cerebral vessels and pregnant women in the first trimester due to complex operation principles of MRI scanner. Future mothers are scanned with low-Tesla scanners in subsequent months of pregnancies. For lactating mothers, there is no restriction, but the baby should be breastfed, after the contrast agent is excreted from the body, if it is used for MRI scan (24 hours). Longer scan interval and mild noises are characteristics that differs it from the computerized tomography. It may be necessary to administer a dye (contrast agent) into a vein to evaluate the diseased region and healthy structures better and to guide the treatment. MRI is the imaging modality with highest resolution especially to examine the soft tissues. MRI scans take longer time (20 to 30 minutes). Sometimes, MRI-specific dyes can be instilled through rectum or blood vessels to differentiate the diseased tissue from the healthier one. MRI is used to determine spread of tumors that are seen in colonoscopy to colonic walls and surrounding tissues. Cross-sectional images that can be defined as thin slices are acquired on various planes to determine the spread of mass lesions and plan the treatment.
The strength of magnetic field created by the magnet of MRI scanner is expressed as Tesla. One Tesla is equal to 10.000 Gauss. Critical determinants of a quality image include strength of magnetic fields, its sustainability and regularity that also shape the main magnetic field.
TYPES OF MRI
T1- and T2-weighted images: These techniques are used to see the anatomy and determine the pathology. MRI subgroups: Diffusion MRI, MR Angiography, cerebrospinal fluid flow MRI, MR Spectroscopy, Perfusion MRI and Functional MRI
MRI AND COLORING
Coloring provides great convenience in MRI. When perfusion and functional MRIs are color coded, it appeals to the eye and the comprehension. Color coding is a time-consuming and laborious process that is performed by computer software. Sometimes, a color coding process takes two days.
WHICH DIAGNOSES DOES MRI HELP?
%50: Nervous system studies, such as spinal column, spinal cord, brain, head, neck, neuro-radiology and herniated cervical and lumbar discs.
%30-35 : Soft tissue and bones, also called musculoskeletal system.
%15-20: Abdomen, breast and soft tissue lesions.
CRANIAL MRI
It is the imaging modality with highest sensitivity to determine chronic nervous system diseases such as brain tumors, strokes, dementia and multiple sclerosis. Moreover, it also offers highest sensitivity to evaluate diseases of pituitary gland, cerebral vessels, eyes and inner ear organs. Since the brain structure is examined, it also helps evaluation of mental disorders.
MAGNETIC RESONANCE SPECTROSCOPY (MRS)
This imaging modality shows changes of metabolites at cellular level. This technique not only carries out biochemical analyses of pathological tissues, but it also helps investigate biochemical relations in healthy tissues.
DIFFUSION WEIGHTED MRI
Diffusion MRI acquires images that originate from molecular movements of water in the tissue. Diffusion MRI is most commonly used to image the stroke that is one of the most important causes of mortality and morbidity. Its accuracy is very high in diagnosis of acute stroke. CT and conventional MRI techniques cannot demonstrate infarction that developed 1 to 2 hours ago, while diffusion MRI can easily show the infarct at very early stage. Moreover, Diffusion MRI ensures differential diagnosis of intracranial cystic formations and of benign and malignant tumors in spinal fractures secondary to the spinal compression caused by tumor and it shows ADC increase in MS plaques.
PERFUSION-WEIGHTED MRI
This technique offers information about the functional status of brain tissue. PW MRI demonstrates hemodynamic changes in cerebral tissue secondary to damage and space occupying lesions. It is clinically used for non-invasive evaluation of stroke, intracranial tumors, dementia and cognitive disorders as well as physiological changes.
FUNCTIONAL MRI (FMR)
It is a very valuable scanning method to analyze the risk of surgery and plan the operation by measuring changes in oxygen and blood supply to the brain. The most important and up-to-date field of use is to create preoperative functional maps with sufficient quality for space occupying lesions that are located to sensorial, motor and speech centers in brain.
MR ANGIOGRAPHY
Blood vessels are imaged in detail without inserting a catheter and emitting radiation beams. It is used to image intracranial blood vessels as well as aorta and blood vessels of kidneys, lungs, arms and legs.
CARDIOVASCULAR SYSTEM MRI
It is used to determine structure and function of heart and great arteries and size and wall thickness of cardiac chambers as well as damage to the heart secondary to myocardial infarction or progressive heart disease. Coronary artery imaging, functional studies and stress perfusion MRI studies are ever increasingly promising. MR Angiography can easily and accurately determine stenosis and other problems in renal arteries for hypertensive patients and evaluate blood vessels of liver, lungs, arms and legs.
TOTAL BODY MRI
Heart, great arteries, lungs, liver, kidneys, spleen, pancreas, gall bladder, bile ducts and intra-abdominal blood vessels are imaged in detail. Cholangiopancreaticography is a study specific for gall bladder, bile ducts and pancreatic canal and intraluminal structures can be easily visualized in a detailed manner without need to insert a catheter. Moreover, it is a good imaging alternative of female and male reproductive organs, pelvic organs (pelvic floor; muscle layers hanging like a hammock between the pubic bone (the foremost part of pelvic bone) and the lower part of the vertebral column (sacrum and coccyx); these supportive muscle layers are called pelvic floor) and urinary bladder.
BREAST MRI
Breast MRI is not a substitute for mammography or ultrasound, but it is a modality that is used in combination with other two diagnostic techniques. In breast imaging, MRI and all other imaging modalities are used for early diagnosis of breast tumors. It can be used to search multiple foci in both breasts (most breast cancers develop in multiple foci) and to screen breast cancers in patients who are not good candidates for mammography due to silicone implants or dense breast tissue in young patients. However, it is recommended to clarify whether a lesion determined with mammography and ultrasound is benign or malignant.
PROSTATE MRI
MRI is used to diagnose the most common disease of prostate (prostatitis – the inflammation of prostate gland), benign hyperplasia of prostate and prostate cancer. Moreover, it is also a good method to determine size of tumor and spread of tumor to other organs which are two determinative factors in decision and course of treatment in patients with biopsy-proven prostate cancer.
MUSCULOSKELETAL SYSTEM MRI
It provides detailed information about muscles, tendons, ligaments, meniscuses, other joint discs, joint capsule and peripheral soft tissues. It is commonly used to evaluate sport-induced tissue injuries, other limb injuries, active and past disorders of joints, inflammatory conditions (arthritis) and inflammatory conditions and tumors of musculoskeletal system as well as spread of tumors that begin in other organs to bones. Moreover, it helps evaluate vertebral problems, such as herniated disc (herniated cervical and lumbar discs) and scoliosis, and postoperative effects of spinal surgery.
PREPARATION AND SCAN PHASES OF MRI
An MRI scan does not require an extra preparation. Unless otherwise is instructed, patients can eat, drink and take medicines before the scan. Patients should fill in a medical history form for the MRI scan. Moreover, patients should remove objects that are affected by magnetic field, such as clock, credit card, metallic objects etc., before entering the MRI room.
Unless otherwise is instructed, patients may void before the scan, if the urinary bladder is distended. The scan usually lasts 15 to 45 minutes. Patients are asked not to move at this interval. Patients should know that even a minor movement may distort the images. Specially designed MRI-specific contrast agents can be injected for certain cases in order to improve image quality and safety of diagnosis. These dyes will help improve details of images acquired by MRI scanner.
DIFFERENCES BETWEEN MRI AND CT
In comparison to CT, MRI is superior in following conditions:
1. MRI shows healthy and diseases tissues more clearly. Moreover, it uses magnetic signals rather than radiation (X-ray) that is used in CT in order to demonstrate density differences between tissues.
2. MRI allows a cross-sectional investigation and accordingly three-dimensional demonstration of anatomic structures. On the other hand, CT images are limited to horizontal slices.
3. In MRI, neither patients nor practitioners are exposed to ionizing radiation.
4. MRI can image blood vessels without a need for contrast agent through the signals derived from the circulating blood. Accordingly, risks and problems arising out of iodine contrast agent, as is the case with CT, are not experienced.
5. MRI allows establish unique tissue diagnosis in the clinical practice that is based on analysis of metabolic processes on viable tissue. It is also necessary to emphasize that comparing to CT, MRI is more influenced by experiences and knowledge of the practitioner. Practitioners need to investigate best physical parameters over the time to study the case.
SUPERIORITIES OF MRI
Superiorities of MRI to conventional radiology studies, including computerized tomography, are as follows:
• X-rays will always pose risk of biological, physical and genetic damage.
• Absence of need to use contrast agent; use of these dyes cause allergic reactions that are frequently impossible to predict and may follow a very severe course in some cases. MRI is preferred due to these two superiorities even if diagnostic value is comparable. Moreover, it is necessary to emphasize important clinical – diagnostic characteristics that are based on determination of biochemistry-derived tissue changes, which cannot be demonstrated by conventional radiology studies. Therefore, MRI have other superiorities:
It enables definitive diagnosis of diseases that cannot be verified with conventional radiology or emerge in very late stage.
It allows differential diagnosis, which is very close to definitive diagnosis, of certain diseases that show similar characteristics in conventional radiology studies (i.e. benign and malignant tumors, inflammatory processes, degenerative processes). The far higher diagnostic specificity of MRI makes biopsy and surgical examination, which are usually necessary for definitive diagnosis of diseases that are examined with conventional diagnostic methods, unnecessary, as these procedures affect integrity of the body.
INFERIORITIES OF MRI
Although it has significant superiorities, MRI has certain inferior aspects, as is the case with all techniques. Such aspects should be known and they should not be ignored in order not to exacerbate a novel technique in comparison to older modalities. A typical inferiority of MRI is the longer scan interval relative to the computerized tomography. This condition is due to very low resonance signal that accumulates at the detector coil. It takes longer time to sample the signal and obtain an appropriate signal/image ratio. However, it can be speculated that significant advancements are made to shorten the scan interval of MRI comparing to last several years. Relatively slow sequences are really switched to ever accelerating sequences. Recently, it is possible to acquire images within several seconds or fractions of second, although it is not very satisfactory from clinical point of view. The second inferior aspect is the high cost of MRI scanner. Superconductor devices that offer higher-quality results lead to higher costs in terms of equipment, installation and operation. However, quick changes are also experienced in this issue.
New devices are developed that are based on superconductor technologies or other technologies with lower operating expenditures. MRI is regarded as a non-hazardous modality, as X-ray is not used. However, it might lead to side effects. The magnetic field required for MRI scan may cause displacement of metallic objects, i.e. metal clips used to correct vascular aneurysms. The radiofrequency may interfere with functions of electronic devices, such as pacemaker. Due to interferences between intensive care unit devices, such as patient monitors, and MRI, significant difficulties are faced in patients, who are monitored and treated with these devices, in MRI scans. If it is necessary to make quick examinations without interfering with function of assistive devices and detailed examination of bones or osseous tissues with calcium deposition is required, computerized tomography is preferred.
CLINICAL USE OF MRI
Nowadays, clinical studies that use MRI are rather focused on examination of the central nervous system. Cranial MRI has following diagnosis superiorities:
• Qualified determination of the difference between the white matter and the gray matter.
Ability to reveal out nervous diseases that cause loss of myelin at early stage and to examine the physiological process of myelinating (development of myelin sheath around the nervous fibers) in children and distortions in maturation of the nervous system.
• Qualified demonstration of pathological processes in posterior cranial fossa, such as cerebellar diseases. Despite all these superiorities, it ensures diagnosis of nervous, degenerative or inflammatory diseases that caused diagnostic difficulty to date.
MAMMOGRAPHY
It is the most common method along with ultrasound for the diagnosis of breast diseases. Magnetic resonance imaging (MRI) and scintigraphy can be used in the second stage, if required. Mammography is still the gold standard in diagnosis of breast cancer.
1. WHY SHOULD I UNDERGO MAMMOGRAPHY?
Breast cancer is a very prevalent disease that one of approximately every ten women catches this disease at any stage of life. Mammography might demonstrate some early signs of cancer even if the lump – swelling at early stage cannot be recognized by the patient or the doctor who examines her. Studies conducted in certain developed Northern Europe countries, the U.S. and Canada since 1960s report that mammography screening decreased breast cancer deaths approximately by 30 percent.
2. WHEN AND HOW FREQUENTLY SHOULD I HAVE A MAMMOGRAM?
The risk of breast cancer increases especially after age of forty. Therefore, screening mammographies are studied annually starting at age of 40 as an optimal approach.
3. IF I RECOGNIZE A LUMP IN MY BREAST BEFORE 40 OR MY DOCTOR SUSPECT OF A LUMP, WHAT SHOULD BE DONE?
In this case, an ultrasound is first studied. Mammography can also be studied, if required. Optimal approach includes both mammography and ultrasound for a patient who is older than forty.
4. HOW IS BREAST CANCER DIAGNOSED WITH MAMMOGRAPHY AND ULTRASOUND?
WHAT IS DONE IN CASE OF A CANCER SUSPECT?
Mammography and breast ultrasound are basic devices that are used to image breasts. Recently, radiologists who are experienced in this field use advanced devices that utilize digital technology and thus, they can differentiate benign and malignant conditions in most of changes or lumps that are demonstrated in the breast. Swellings palpated by the patient or the doctor are mostly benign tumors or cysts. These non-hazardous lumps (fibroadenoma and similar formations) and cysts are very prevalent especially at the age range of 30 to 50 years. Most of them can be differentiated from cancer with ultrasound and mammography. In case of cancer suspect, radiologist informs the patient that a biopsy is required and the referring doctor is contacted; next, he decides how the biopsy sample will be taken. The lumps with very low risk of cancer are followed up with ultrasound and/or mammography at intervals of several months and the risk of cancer is ruled out if it is verified that they do not change or grow.
