Barry Stein

Noninvasive evaluation of active lower gastrointestinal bleeding: comparison between contrast-enhanced MDCT and 99mTc-labeled RBC scintigraphy.

OBJECTIVE The purpose of our study was to compare contrast-enhanced MDCT and (99m)Tc-labeled RBC scanning for the evaluation of active lower gastrointestinal bleeding. SUBJECTS AND METHODS Over 17 months, 55 patients (32 men, 23 women; age range, 21-92 years) were evaluated prospectively with contrast-enhanced MDCT using 100 mL of iopromide 300 mg I/mL. Technetium-99m-labeled RBC scans were obtained on 41 of 55 patients and select patients underwent angiography for attempted embolization. Each imaging technique was reviewed in a blinded fashion for sensitivity for detection of active bleeding as well as the active lower gastrointestinal bleeding location. RESULTS Findings were positive on both examinations in eight patients and negative on both examinations in 20 patients. Findings were positive on contrast-enhanced MDCT and negative on (99m)Tc-labeled RBC in two patients; findings were negative on contrast-enhanced MDCT and positive on (99m)Tc-labeled RBC in 11 patients. Statistics showed significant disagreement, with simple agreement = 68.3%, kappa = 0.341, and p = 0.014. Sixteen of 60 (26.7%) contrast-enhanced MDCT scans were positive prospectively, with all accurately localizing the site of bleeding and identification of the underlying lesion in eight of 16 (50%). Nineteen of 41 (46.3%) (99m)Tc-labeled RBC scans were positive. Eighteen of 41 matched patients went on to angiography. In four of these 18 (22.2%) patients, the site of bleeding was confirmed by angiography, but in 14 of 18 (77.8%), the findings were negative. CONCLUSION Contrast-enhanced MDCT and (99m)Tc-labeled RBC scanning show significant disagreement for evaluation of active lower gastrointestinal bleeding. Contrast-enhanced MDCT appears effective for detection and localization in cases of active lower gastrointestinal bleeding in which hemorrhage is active at the time of CT.

Reduced Z-axis coverage multidetector CT angiography for suspected acute pulmonary embolism could decrease dose and maintain diagnostic accuracy

Multidetector computed tomographic angiography (MDCTA) is the method of choice for evaluation of suspected acute pulmonary embolism (PE) in most patients because it is accurate and widely available. The use of computed tomography, including MDCTA for PE, has risen dramatically over the last several years with an attendant rise in radiation exposure. Many methods currently employed to reduce radiation dose may affect image quality and potentially affect diagnostic accuracy. Reducing Z-axis coverage would decrease radiation dose without any effect on image quality. This study was performed to assess the effect on the accuracy of MDCTA for suspected acute PE if the Z-axis coverage was reduced to the anatomic range from the top of the aortic arch through the heart. Two hundred ninety-five examinations were performed on a 64-detector-row MDCT and interpreted as positive for PE from July 2005 to February 2008. When the anatomic range of these data sets were retrospectively reduced and reinterpreted for PE, no case was interpreted as negative for PE. The Z-axis coverage was reduced by 37%. In the interest of keeping radiation doses as low as reasonably achievable, further research in this area is warranted.

Angiographic diagnosis and transarterial embolization of iatrogenic ovarian artery injury.

PELVIC and genital bleeding remains a major cause of morbidity and mortality in the female reproductive tract. Its management is an important issue to obstetricians and gynecologists. Endovascular embolization is a well-documented technique that has been employed for controlling pelvic hemorrhage. This technique has been used to treat postpartum hemorrhage (1), as well as hemorrhage related to postoperative gynecologic surgery (2). We present two cases in which patients underwent salpingo-oophorectomies that were complicated by postoperative hemorrhage, requiring emergent endovascular embolization. In both patients, selective bilateral internal iliac angiography failed to demonstrate an active bleeding site. Consequently, selective catheterization of the ovarian artery confirmed it as the source of hemorrhage, which was then successfully treated with intravascular embolization.