Radiology

Kato, N; Dake, M D; Miller, D C; Semba, C P; Mitchell, R S; Razavi, M K; Kee, S T

doi: N/Apmid: 9393517

PURPOSE: To demonstrate the feasibility and safety of endovascular stent-graft placement for treatment of traumatic aortic aneurysm. MATERIALS AND METHODS: Ten patients with traumatic aortic aneurysm were treated with endovascular stent-grafts. Three patients had an acute traumatic aneurysm; seven had a chronic aneurysm. Stent-grafts were constructed from modified Z-stents covered with woven polyester or expanded polytetrafluoroethylene graft material and were deployed through a 20-24-F delivery sheath in an exposed artery located remotely from the lesion. RESULTS: Stent-graft placement and thrombosis of the aneurysmal sac were successful in all patients. Major complications were encountered in three patients after endovascular treatment. One patient had a peri-graft leak; complete thrombosis of the aneurysmal sac was achieved after coil embolization of the leak. Transposition of the left subclavian artery was necessary to relieve left arm ischemia in another patient. In the third patient, stent placement in the left main stem bronchus was needed to relieve left lung atelectasis. All patients were alive and without complications during the follow-up period (mean, 15 months). CONCLUSION: Transluminal placement of endovascular stent-grafts is a technically feasible method for treatment of traumatic thoracic aortic aneurysm and may be an effective alternative to open-chest surgery.

Robbin, M L; Lockhart, M E; Weber, T M; Vitek, J J; Smith, J K; Yadav, J; Mathur, A; Iyer, S S; Roubin, G S

doi: N/Apmid: 9393531

PURPOSE: To determine whether ultrasound (US) is a sensitive follow-up method after placement of a carotid artery stent for the detection of significant stenosis, occlusion, and other complications at early and intermediate follow-up. MATERIALS AND METHODS: Doppler US examinations were performed after stent placement in 170 carotid arteries in 119 patients with angiographic correlation. Prospective diagnostic US criteria for stenosis were peak-systolic velocity greater than 1.25 m/sec, internal carotid artery (ICA) to common carotid artery (CCA) peak-systolic velocity ratio of greater than or equal to 3:1, and intrastent doubling of peak-systolic velocity. Retrospective criteria for stenosis were also applied: peak-systolic velocity greater than 1.7 m/sec, ICA end-diastolic velocity greater than 0.4 m/sec, ICA/CCA peak-systolic velocity ratio greater than 2.0, and ICA/CCA end-diastolic velocity ratio greater than 2.4. RESULTS: Eighty-seven immediate and 83 intermediate (average, 7.3 months) follow-up US examinations were performed. Two stent occlusions were detected. One or more prospective US criteria were abnormal in 26 arteries with a stent. One or more retrospective criteria were positive in 47 arteries. Angiography showed corresponding findings, with only one significant stenosis (63%) in the ICA stents. Moderate collapse of a CCA stent was depicted at US. CONCLUSION: Only one significant recurrent stenosis was detected, and no significant stenoses were missed at US. US successfully depicted carotid artery stent occlusion and a moderate stent collapse. Sensitivity in the detection of intrastent stenosis is promising. Further study to refine US criteria in a study with longer term follow-up is needed owing to the lack of significant recurrent stenosis in the intermediate follow-up group.

Oser, A B; Moran, C J; Kaufman, B A; Park, T S

doi: N/Apmid: 9393539

PURPOSE: To evaluate whether very early magnetic resonance (MR) imaging enables distinction of residual tumor from benign postoperative change in children. MATERIALS AND METHODS: Forty-six postoperative MR examinations were performed in 43 children with intracranial tumors within 24 hours of the completion of surgery during a 2-year period. These examinations were categorized according to whether residual tumor could be definitely identified or excluded, or whether the diagnosis was uncertain. RESULTS: Contrast enhancement occurred in 33 of 46 MR examinations performed within 24 hours of surgery. In 18 instances, this was associated with obvious residual tumor. In 15 patients, only small amounts of linear or patchy enhancement were seen. Of these, seven patients (46%) were disease-free for an average of 4.5 years. Assessment for postoperative enhancement was hampered in seven patients because of the presence of methemoglobin in the tumor bed. Contrast enhancement was not observed in two patients before surgery. CONCLUSION: Surgically induced, MR-detectable contrast enhancement and extracellular methemoglobin formation occurs within 24 hours of the completion of intracranial surgery. This can interfere with the detection of small amounts of residual tumor.

Levine, D; Hulka, C A; Ludmir, J; Li, W; Edelman, R R

doi: N/Apmid: 9393534

PURPOSE: To determine the value of transabdominal ultrasound (US), transvaginal US, color Doppler US, power Doppler US, and magnetic resonance (MR) imaging in the diagnosis of placenta accreta. MATERIALS AND METHODS: Nineteen patients in the third trimester of pregnancy who were at risk for placenta accreta underwent color Doppler and power Doppler US; 18 patients also underwent MR imaging. Images were interpreted prospectively for signs of accreta by two reviewers. The reviewers' confidence in their diagnosis was graded on a five-point scale. RESULTS: Outcomes at delivery were as follows: normal placenta (n = 11), hysterectomy owing to uncontrollable bleeding (n = 1), and placenta accreta (n = 7). Five cases of lower-uterine-segment placenta accreta were diagnosed with a high level of confidence with vaginal and power Doppler US. In one patient with a posterior placenta who had previously undergone myomectomy, MR imaging enabled the diagnosis of placenta accreta, which was not well depicted at US. CONCLUSION: In patients with a history of uterine scars, vaginal US with power Doppler US performed well in the evaluation of lower-uterine-segment placenta accreta. MR imaging depicts posterior placenta accreta.

Berkefeld, J; Kirchner, J; Müller, H M; Fries, U; Kollath, J

doi: N/Apmid: 9393536

PURPOSE: To define the indications and contraindications for balloon dacryocystoplasty. MATERIALS AND METHODS: Eighty-five patients with severe epiphora due to partial (n = 47) or complete (n = 38) obstruction of the nasolacrimal duct (NLD) were treated with balloon dacryocystoplasty (DCP). Steerable micro-guide wires with flexible tips were used. Success rates of DCP were evaluated clinically and dacryocystographically during the acute phase and at 6- and 12-month follow-up. Failures and recurrences were correlated with clinical and dacryocystographic indications for treatment. RESULTS: Recanalization was successful in 35 (92%) of 38 patients with isolated focal stenoses (n = 20) or short-distance occlusions (n = 18) of the NLD. Among all 85 patients, recanalization was successful in 25 patients (66%) with complete and 37 patients (79%) with partial obstructions. In the absence of the main predictors for recurrent obstructions (ie, active inflammation, filling defects due to calculi, long-distance occlusions, and posttraumatic lesions), 12-month patency rates were 89% (17 of 19 focal stenoses) and 94% (15 of 16 focal occlusions). Otherwise, reobstruction rate was 46% (12 of 26 cases). CONCLUSION: Balloon dacryocystoplasty is successful only in select cases. To achieve results comparable to those of operative treatment, the indication should be limited to patients with circumscribed focal stenoses or occlusions of the NLD. Active dacryocystitis, dacryocystolithiasis, and posttraumatic lesions are the main contraindications.

Therasse, E; Choinière, M; Soulez, G; Oliva, V L; Rousseau, P; Fugère, F; Boudreault, D; Cusson, J R

doi: N/Apmid: 9393518

PURPOSE: To determine the analgesic efficacy and safety of interpleural block for percutaneous biliary drainage. MATERIALS AND METHODS: In this double-blind study, 34 age- and sex-matched patients who were to undergo percutaneous biliary drainage because of malignant biliary obstruction were randomly assigned to the true-block group (30 mL 0.5% bupivacaine block) or placebo-block group; all had access to a patient-controlled analgesia (fentanyl) pump. Self medication, pain reports, blood pressure, heart rate, and oxygen saturation were monitored during and until 8 hours after drainage. The McGill Pain Questionnaire was administered 1 hour after biliary drainage. RESULTS: Patients in the placebo group self administered statistically significantly more fentanyl than did patients in the true-block group (P = .008). Peak pain scores (10-point scale) and McGill Pain Questionnaire scores were statistically significantly higher for the placebo group patients (P = .017 and P = .001, respectively). There were no differences between groups in terms of blood pressure, heart rate, and oxygen saturation. Two patients had pneumothorax caused by the interpleural block. CONCLUSION: Interpleural block was effective in decreasing pain and opioid requirements during and after percutaneous biliary drainage and did not compromise the cardiopulmonary status of the patient. However, the rate of pneumothorax was higher than previously reported.

Donnelly, L F; Klosterman, L A

doi: N/Apmid: 9393541

PURPOSE: To determine if computed tomographic (CT) findings of decreased contrast material enhancement are predictive of more intense illness and of the development of cavitary necrosis in children with pneumonia. MATERIALS AND METHODS: Contrast-enhanced CT scans in 44 children with pneumonia who did not respond appropriately to therapy were compared with precontrast CT scans to evaluate enhancement of consolidated lung parenchyma. Enhancement was correlated with admission to the intensive care unit, length of hospital stay, cavitary necrosis in the lung at follow-up CT, and frequency of lung resection. RESULTS: Parenchymal enhancement was decreased in 21 children; pneumonia was enhanced in the other 23 children. Decreased enhancement was associated with increased admission to intensive care (14 of 21 67% vs five of 23 22% children; P = .0026), increased length of hospital stay (15 vs 10 days; P = .0615), increased frequency of cavitary necrosis at follow-up CT (seven of seven 100% vs none of three children; P = .0086), and increased frequency of resection (two of 21 10% vs none of 23 children). At histopathologic examination, diffuse cavitary necrosis was present in resected lobes in two patients. CONCLUSION: Decreased parenchymal enhancement at CT is a predictor of more intense illness and may herald the development of cavitary necrosis in children with pneumonia.

Szymski, G X; Albazzaz, A N; Funaki, B; Rosenblum, J D; Hackworth, C A; Zernich, B W; Leef, J A

doi: N/Apmid: 9393519

PURPOSE: To evaluate percutaneous placement of pull-type gastrostomy tubes that has traditionally necessitated endoscopic guidance. MATERIALS AND METHODS: From September 1995 through March 1997, 63 pull-type gastrostomy tubes were placed in 64 patients. Retrograde catheterization of the esophagus was performed through the stomach. Then the gastrostomy tube was pulled through from the mouth into the stomach. RESULTS: Gastrostomy tube placement was successful in 63 (98%) of 64 patients in 65 attempts. One procedure was stopped when the patient reported chest pain after gastric insufflation, and a second placement attempt was initially unsuccessful. Major complications occurred in three (5%) patients: exit site infection necessitating tube removal (n = 2) and prolonged bleeding necessitating transfusion (n = 1). Minor complications occurred in six (9%) patients: failure of placement (n = 2), exit site infection (n = 1), leakage around the tube (n = 1), tube migration (n = 1), and inadvertent tube removal (n = 1). There were no cases of peritonitis, tract disruption, or gastrostomy-related death. CONCLUSION: Percutaneous placement of a pull-type gastrostomy tube was performed with a minimum risk of tract disruption and peritonitis. The tube was safely and effectively placed by radiologists.

Vogl, T J; Stupavsky, A; Pegios, W; Hammerstingl, R; Mack, M; Diebold, T; Lodemann, K P; Neuhaus, P; Felix, R

doi: N/Apmid: 9393527

PURPOSE: To analyze the potential of gadobenate dimeglumine-enhanced magnetic resonance (MR) imaging for the characterization and diagnosis of hepatocellular carcinoma (HCC) by using static and dynamic sequences. MATERIALS AND METHODS: Twenty-eight patients with histopathologically proved HCC were evaluated with T1- and T2-weighted spin-echo and static and dynamic gradient-echo sequences before, during, and after intravenous administration of 0.1 mmol/kg gadobenate dimeglumine (0.5 mol/L). RESULTS: During the perfusion phase of the dynamic sequence, all 16 nodular well-differentiated HCC lesions showed a rapid increase in signal intensity 10-30 seconds after injection followed by a progressive decrease in signal intensity. The nine poorly differentiated HCC lesions showed no rapid increase in signal intensity. All eight large (> 3 cm), nodular, well-differentiated HCC lesions showed a hypointense rim before injection and both hypo- and hyperintense rims (double-ring sign) immediately after injection, compared with normal liver parenchyma. About 55 seconds after injection, substantial single-rim enhancement was detected in 21 of the 28 HCC lesions. CONCLUSION: Dynamic gadobenate dimeglumine-enhanced MR imaging allows improved characterization of HCC lesions, which show rapid increase in signal intensity during the early, arterial phase in well-differentiated HCC lesions and a double-ring sign in large well-differentiated nodular HCC lesions.

Hopper, K D; King, S H; Lobell, M E; TenHave, T R; Weaver, J S

doi: N/Apmid: 9393547

PURPOSE: To evaluate the ability of thin overlying bismuth radioprotective shielding to reduce the x-ray dose to radiosensitive superficial organs during diagnostic computed tomography (CT). MATERIALS AND METHODS: A variety of patient and phantom studies were performed with four thicknesses of bismuth radioprotective latex over the breast. Dose savings were determined with thermoluminescent dosimeters. A prototype and then a final manufactured radioprotective brassiere was constructed and tested for radiation dose savings to the breast during diagnostic chest CT. Preliminary studies were also performed to evaluate shielding of the thyroid, orbit, and testes. RESULTS: The use of bismuth radioprotective latex saved an average 57% of the radiation dose to the breast from thoracic CT, decreasing the radiation level from an average 2.2 rad (0.022 Gy) to 1.0 rad (0.010 Gy) (P < .001). Preliminary tests of shielding other superficial radiosensitive organs frequently included at diagnostic CT (eyes, thyroid gland, and testes) were performed with the same thickness of overlying bismuth radioprotective latex, with similar results. Radiation to the thyroid gland was reduced by 60% (from 0.0573 to 0.0229 Gy) and radiation to the eye and testes was reduced by 40% (from 0.0256 to 0.0154 Gy) and 51% (from 0.0463 to 0.0229 Gy), respectively. CONCLUSION: The use of in-plane overlying bismuth radioprotective latex manufactured into form-fitting garments did not affect the diagnostic CT image but reduced the amount of radiation to radiosensitive superficial structures.