Radiology

Lynch, D A; Brasch, R C; Hardy, K A; Webb, W R

doi: N/Apmid: 2353097

High-resolution computed tomography (HRCT) is widely used to assess pulmonary parenchymal disease in adults. The authors used ultrafast CT with 3-mm collimation and a 100-msec scan time to obtain HRCT scans in 36 children (mean age, 49.4 months). Clinical diagnoses included normal lungs (n = 6), cystic fibrosis (n = 12), obliterative bronchiolitis (n = 6), idiopathic pulmonary hemosiderosis (n = 2), and other lung diseases (n = 10). The HRCT scans and chest radiographs were reviewed separately in blinded fashion. Pulmonary parenchymal abnormalities were categorized into interstitial, airspace, and airway processes. Nine patients with normal chest radiographs had abnormal HRCT scans. In five other patients, the extent of abnormal lung parenchyma was considerably greater on HRCT scans than on chest radiographs. HRCT scans allowed accurate characterization of the type of lung process in 24 of 30 patients when compared with clinical or biopsy findings. Early HRCT findings in cystic fibrosis included lobular air trapping, bronchial wall thickening, and centrilobular nodules. The use of cine CT with high-resolution techniques is feasible in children too young or too sick to hold their breath. HRCT may enable early detection and characterization of pulmonary disease and depiction of the extent of lung abnormality.

Birnbaum, B A; Weinreb, J C; Megibow, A J; Sanger, J J; Lubat, E; Kanamuller, H; Noz, M E; Bosniak, M A

doi: N/Apmid: 2191377

Thirty-seven patients with 69 suspected hemangiomas found by means of computed tomography (CT) and/or ultrasound were studied with both 0.5-T magnetic resonance (MR) imaging and single photon emission CT (SPECT) with technetium-99m-labeled red blood cells. Using a criterion of "perfusion-blood pool mismatch," SPECT readers diagnosed 50 of 64 hemangiomas and all five "nonhemangiomas" (sensitivity, 78% 95% confidence interval, 0.664 - 0.864; accuracy, 80% 0.69 - 0.877). Qualitative analysis of lesion signal intensity on T2-weighted spin-echo MR images allowed readers to diagnose 58 of 64 hemangiomas and four of five nonhemangiomas (sensitivity, 91% 0.814 - 0.96; accuracy, 90% 0.807 - 0.951). Because of the significantly higher cost of MR imaging and its inability to categorically differentiate hemangiomas from hypervascular metastases, the authors consider SPECT to be the method of choice for diagnosing hepatic hemangiomas. MR imaging should be reserved for the diagnosis of lesions smaller than 2.0 cm and for those 2.5 cm and smaller adjacent to the heart or major hepatic vessels; in such cases MR imaging was found superior to SPECT.

Manaster, B J; Coleman, D A; Bell, D A

doi: N/Apmid: 2353085

Free vascularized fibular grafting, in which the peroneal artery is harvested with the fibula, is a popular procedure for filling osseous defects and for treatment of femoral head avascular necrosis. Preoperative vascular imaging is required in all patients to detect the origin of the peroneal artery, to measure the length available for the vascular pedicle, and to evaluate for the normal continuation of the three major vessels of the lower leg. Magnetic resonance imaging of the lower leg with use of gradient-recalled acquisition in a steady, state was performed in 35 patients to evaluate vascular anatomy. Surgical correlation was available in 91% of cases, and in these 100% accuracy was demonstrated. Postoperative radiographs showed that grafts placed for osseous defects in the upper extremity were incorporated and hypertrophied extremely quickly, while those placed in the major weight-bearing bones of the lower extremity were much more prone to complications including delayed union, fracture, and infection. Vascularized grafts placed in the femoral head and neck for avascular necrosis incorporate only in the cephalic portion and should be watched carefully for signs of early and progressive femoral head collapse.

LaBerge, J M; Ponec, D J; Gordon, R L

doi: N/Apmid: 2353103

The authors describe a modification of previously described techniques for fallopian tube catheterization. Tubal catheterization was performed with standard techniques in nine patients. In nine patients tubal catheterization was achieved with a metal self-retaining uterine cannula and catheter set. The authors believe that the modified equipment offers several advantages over other available systems.

Cohan, R H; Dunnick, N R; Leder, R A; Baker, M E

doi: N/Apmid: 2353113

The authors report four large-volume (greater than 20-mL) extravasations in adults and one intermediate-volume (18-mL) extravasation in an infant of iopamidol, a nonionic contrast medium, that occurred during dynamic enhanced computed tomography. The largest volume that extravasated (in two patients) was 150 mL. Although all five patients initially had swelling, erythema, and/or pain after extravasation, all recovered uneventfully. The authors suggest that emergent surgical drainage of all large-volume extravasations, a procedure that was recently recommended, is unnecessary. Large extravascular collections of nonionic contrast media can be well tolerated and are often resorbed without adverse sequelae.

Spritzer, C E; Pelc, N J; Lee, J N; Evans, A J; Sostman, H D; Riederer, S J

doi: N/Apmid: 2353099

To assess blood flow rapidly, a limited-flip-angle, gradient recalled pulse sequence was modified to acquire two views at the same phase-encoding step in successive repetitions. One view is obtained with first-moment flow compensation, while the second view is obtained with selectable flow encoding (non-zero first moment) along one direction. Blood flowing along the encoded direction acquires a phase difference between the two views, resulting in signal dependent on both direction and speed of flow. Stationary tissues undergo no phase change. Therefore, the phase shift between the two views produces an image that spatially renders flow direction and velocity. With a 24-msec repetition time, a 256 X 128 matrix, and two excitations, data acquisition is completed in 13 seconds per location (both a magnitude image and a flow image are produced at each location). Images generated with flow phantoms confirmed the accuracy of this method. Preliminary clinical evidence in 23 human subjects suggests that this method is useful in evaluating portal hypertension, distinguishing arterial from venous flow, distinguishing between slow flow and clot, and confirming the presence of clot. This method appears to be a fast, easy way to assess blood flow in large vessels.

Bowen, A D; Keslar, P J; Newman, B; Hashida, Y

doi: N/Apmid: 2191375

During orthotopic liver transplantation, ligation and division of the right adrenal vein during recipient hepatectomy may lead to hemorrhagic infarction and/or hematoma formation in the right adrenal gland. Findings in seven liver transplant recipients included initially echogenic or anechoic suprarenal masses on ultrasound scans and inhomogeneous but predominantly hypoattenuating masses on computed tomographic scans. In patients who survived for 4 months or longer, hematomas resolved as early as 20 days and persisted as long as 11 weeks. There was autopsy proof of adrenal hemorrhage in three cases. The adrenal hematomas in this series produced no massive hemorrhages, adrenal insufficiency, or other clinical manifestations. Adrenal hemorrhage after liver transplantation should be recognized and specifically documented, but a hematoma that remains stable in size can be left alone.

Becker, G J; Palmaz, J C; Rees, C R; Ehrman, K O; Lalka, S G; Dalsing, M C; Cikrit, D F; McLean, G K; Burke, D R; Richter, G M

doi: N/Apmid: 2141175

Intravascular stent placement may be an effective treatment for percutaneous transluminal angioplasty (PTA)-induced dissection. Among the first 228 patients treated with Palmaz balloon-expandable intraluminal stents (BEISs) for iliac artery stenosis, stents were used to treat PTA-induced dissection in at least 12 iliac arteries in 11 patients. All 12 vessels were shown by angiography to be severely dissected. Stents were placed at the time of PTA in six vessels and as a separate procedure in the other six. An average of three stents per vessel were employed. All arteries showed marked improvement at angiography. Angiographic follow-up was obtained for eight vessels in seven patients at a mean follow-up time of 12.9 months. All had patent stent lumens with neointima formation, although one stented lumen had narrowed, and another clinical failure occurred despite a patent stented vessel and an ankle-arm index (AAI) of 1.35. With a mean clinical follow-up of 9.5 months, the mean AAI for the stented extremities in the nine remaining patients is 0.91 +/- 0.15. Palmaz BEISs are effective in the management of PTA-induced human iliac artery dissection.

Kalender, W A; Seissler, W; Klotz, E; Vock, P

doi: N/Apmid: 2353088

Continuous computed tomographic (CT) scanning of organ volumes during a single breath hold was studied. The authors modified the table feed mechanism of a continuously rotating CT scanner to allow patient transport at low, but accurately controlled, speeds (0.1-11.0 mm/sec) during continuous 1-second scanning. An algorithm was designed to reconstruct artifact-free images for arbitrary table positions from the helical data by interpolating between adjacent scans. Section sensitivity profiles were enlarged; the section width for a 10-mm section and a speed of 10.0 mm/sec was increased by a factor of 1.3, compared with the nominal value. Clinical examples were presented for studies of lung nodules and studies enhanced with contrast medium. Major advantages are the possibility of continuous scanning of extended volumes within a breath-hold period and retrospective, arbitrary selection of anatomic levels.

Akiyama, H; Okazaki, T; Takashima, I; Satoh, S; Ryan, T; Iwamori, S; Hidaka, T; Morio, K; Okuhara, T

doi: N/Apmid: 2191366

Percutaneous treatment of biliary disease was administered in 173 cases, mainly among high-risk or elderly patients. Diagnosis was acute cholecystitis in 32 cases, acute cholangitis in 16, hepatic abscess in five, gallbladder stones in 28, common bile duct stones in 11, intrahepatic stones in five, malignant obstructive jaundice in 61, and benign biliary stenosis in 15. The treatment was successful in 158 of 173 cases (91.3%). Complications were encountered in 17 (9.8%). Most of these occurred during the initial period and were mild and controllable with conservative treatments. There were two deaths (1.2% of patients); one was not related to the procedure. These data suggest that percutaneous treatments are safe and effective even among elderly or high-risk patients with biliary diseases.