Technical aspect of CT angiography of lower extremities.

Objective: To assess the less invasive technique of CT angiography for evaluation of lower extremity arteries with nonionic water soluble iodinated contrast medium. Methods: One hundred thirty patients underwent a CT angiography of lower extremity using smart prep technique above the iliac creast 1 inch. and the following parameters: Helical, Rotation time : 0.8 seconds, Rotation length : full, Detector configuration : 16X1.25 mm, Helical thickness : 1.25, Pitch : 1.375:1, Speed : 27.50 mm/rotation, Beam collimation : 20 mm, Image interval : 1.0 mm, Gantry tilt : 0.0, SFOV : large, X-ray energy 140 kV, 260 mA. Results: The data of CT Acquisition and Contrast Medium Parameters were Scanning coverage (mm): 1040 ฑ 88, Scanning duration (sec): 33+ 5, Number of transverse sections: 1063+ 348 iodine dose (g): 89.8+ 5.3, Concentration of contrast medium(mg/ml): 356.7+ 24.4, Volume of contrast medium (ml): 120+ 0, Contrast medium injector rate (ml/sec): 4+ 0, Injection duration (sec): 30+ 0, Scanning -to-injection duration ratio: 1.08+ 0.2, Delay between contrast medium initiation and scanning (sec): 26+ 5.3. Conclusion: The conventional study for lower extremity arteries is conventional angiography which is invasive method. This method required admission and absolute bed rest at least 8-12 hours after procedure. The CT angiography takes advantage over conventional angiography, including 3D volumetric analysis, minimally invasive vascular opacification and depiction of mural calcium. The fastest and more slices of current generation of 16 slices multidetector CT scanner is possible to study entire length of lower extremities.

CT criteria for differentiation between true and false lumen in aortic dissection.

Acute aortic dissection can be an emergency event characterized by the splitting of tunica media of the aortic wall by high pressure arterial blood throught an intimomedial tear: The CT imaging is a currently emerging technique for dianosis and evaluation of aortic dissection and has sensitivity and specificity of nearly 100%. The differentiation between true and false lumens of aortic dissection is important for percutaneous treatment with endovascular grafts or surgical repair: Previous studies described CT criteria to distinguish true from false lumens. The most reliable sings in this study are outer wall calcification, intraluminal thrombus, eccentric flap calcification, a larger area at one-quarter distance, and a larger area at one-half distance.

Computed tomography of the pelvis: Utilizing the oil-filled method in evaluation of bladder neoplasm.

Five patients with oil-filled bladders were studied by computed tomography, which dramatically demonstrated the intravesical tumor component. Negative contrast bladder opacification technique is found to be accurate, reproducible and simple. Negative contrast avoids false evaluation near the bladder well from partial volume effect as occurs with positive contrast material. Thus, CT staging of bladder neoplasm may be considered a highly accurate procedure.

Experiences with sonography of abdominal aortic aneurysm.

Real time and conventional contact ultrasonic B scannings of the abdominal aorta are excellent methods to investigate patients with prominent abdominal pulsation. Echo from thrombi may frequently be identified within the aneurysm. It is particularly valuable in differentiating tortuous atherosclerotic aorta from aneurysm. The procedure is noninvasive and causes no discomfort.