Evaluation of focal liver lesions: fast-recovery fast spin echo T2-weighted MR imaging.

PURPOSE: To compare breath-hold fast-recovery fast spin echo (FR-FSE) and non-breath-hold fast spin echo (FSE) T2-weighted sequences for hepatic lesion conspicuity and image quality at MR imaging. MATERIALS AND METHODS: Fifty-nine patients with known or suspected liver lesions underwent hepatic MR imaging by using a breath-hold FR-FSE T2-weighted sequence with and without fat suppression and a non-breath-hold FSE T2-weighted sequence with and without fat suppression. Quantitative analysis was made with measurements of the signal intensity of the liver, spleen, background noise, and up to three liver lesions, as well as calculations of the liver signal-to-noise ratio (SNR) and the liver-to-lesion contrast-to-noise ratio (CNR) for each sequence. Qualitative analysis was made for image quality and the number of lesions identified. Statistical analysis was performed by using a single-tailed paired Student's t test with a 95% confidence interval. RESULTS: SNR and CNR were significantly higher (P<.05) for FSE with fat suppression than for FR-FSE with fat suppression. No statistically significant difference was seen in terms of SNR and CNR between non-fat-suppressed FSE and FR-FSE sequences. Lesion conspicuity, liver edge sharpness, and clarity of vessels were superior and ghosting was less with the FR-FSE sequences compared with the FSE sequences. CONCLUSION: Breath-hold FR-FSE technique is a reasonable alternative in T2-weighted imaging of the liver.

Reminder: radiopacities from metal-containing substances.

A 17-month-old boy with a toed-out left lower extremity was presented for evaluation. Before coming to the doctor, the mother had applied a zinc oxide lotion to treat a simple diaper rash in the groin. The radiologist did not remove the boy's diaper for the radiographic examination and so did not notice the lotion. The first radiograph showed what looked like multiple soft-tissue calcifications in the groin, but the radiopacities had been produced by the zinc oxide. This case serves as a reminder to be aware that metal-containing substances both on and in the body can produce radiopacities.

Efficacy and safety of MR imaging with liver-specific contrast agent: U.S. multicenter phase III study.

PURPOSE: To assess prospectively the efficacy and safety of postcontrast magnetic resonance (MR) imaging with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) compared with that of precontrast MR imaging in patients who are known to have or are suspected of having liver lesions and who are scheduled for hepatic surgery. MATERIALS AND METHODS: Investigational review board approval and written informed consent were obtained. HIPAA went into effect after data collection. A total of 172 patients were enrolled. After precontrast MR imaging, 169 patients (94 men, 75 women; mean age, 61 years; age range, 19-84 years) received an intravenous bolus of 25 micromol/kg Gd-EOB-DTPA and underwent dynamic gradient-recalled-echo and delayed MR imaging 20 minutes after injection. Arterial and portal phase computed tomography (CT) were performed within 6 weeks of MR imaging. The standard of reference was surgery with intraoperative ultrasonography (US) and biopsy and/or pathologic evaluation of resected liver segments and/or 3-month follow-up of nonresected segments if intraoperative US was not available. Three blinded reviewers and unblinded site investigators identified liver lesions on segment maps. The Wilcoxon signed rank test was used to compare differences in per-patient sensitivity of precontrast and postcontrast MR images. Adverse events were recorded, and patient monitoring and laboratory assay were performed at time of injection and up to 24 hours after contrast material administration. RESULTS: At MR imaging, 316 lesions were identified in 131 patients. In 77% (P = .012), 72% (P = .15), and 71% (P = .027) of patients for readers 1, 2, and 3, respectively, more lesions were seen at precontrast and postcontrast MR imaging combined than at precontrast MR imaging alone. Sensitivity values for blinded readings were significantly greater at postcontrast MR imaging than at precontrast MR imaging for two of three blinded readers. For all blinded readers, combined precontrast and postcontrast MR images showed no difference in sensitivity compared with helical CT scans. The use of MR imaging, however, yielded fewer patients with at least one false-positive lesion (37%, 31%, and 34% of patients for readers 1, 2, and 3, respectively) than did helical CT (45%, 36%, and 43% of patients for readers 1, 2, and 3, respectively). CONCLUSION: Compared with precontrast MR imaging, postcontrast MR imaging with Gd-EOB-DTPA demonstrated improved sensitivity for lesion detection in the majority of blinded readers, with no substantial adverse events.

Percutaneous treatment of complications occurring during hemodialysis graft recanalization.

INTRODUCTION/OBJECTIVE: To describe and evaluate percutaneous treatment methods of complications occurring during recanalization of thrombosed hemodialysis access grafts. METHODS AND MATERIALS: A retrospective review of 579 thrombosed hemodialysis access grafts revealed 48 complications occurring during urokinase thrombolysis (512) or mechanical thrombectomy (67). These include 12 venous or venous anastomotic ruptures not controlled by balloon tamponade, eight arterial emboli, 12 graft extravasations, seven small hematomas, four intragraft pseudointimal 'dissections', two incidents of pulmonary edema, one episode of intestinal angina, one procedural death, and one distant hematoma. RESULTS: Twelve cases of post angioplasty ruptures were treated with uncovered stents of which 10 resulted in graft salvage allowing successful hemodialysis. All arterial emboli were retrieved by Fogarty or embolectomy balloons. The 10/12 graft extravasations were successfully treated by digital compression while the procedure was completed and the graft flow was restored. Dissections were treated with prolonged Percutaneous Trasluminal Angioplasty (PTA) balloon inflation. Overall technical success was 39/48 (81%). Kaplan-Meier Primary and secondary patency rates were 72 and 78% at 30, 62 and 73% at 90 and 36 and 67% at 180 days, respectively. Secondary patency rates remained over 50% at 1 year. There were no additional complications caused by these maneuvers. DISCUSSIONS AND CONCLUSION: The majority of complications occurring during percutaneous thrombolysis/thrombectomy of thrombosed access grafts, can be treated at the same sitting allowing completion of the recanalization procedure and usage of the same access for hemodialysis.

Clinical usefulness of imaging performed after CT angiography that was negative for pulmonary embolus in a high-risk oncologic population.

OBJECTIVE: The purpose of our study was to determine the prevalence and types of additional imaging examinations that were performed, and whether anticoagulation therapy was started or continued, after CT angiography showed no pulmonary embolus in a high-risk oncologic population. MATERIALS AND METHODS: We reviewed the radiology report for each CT angiogram that was obtained for clinically suspected pulmonary embolism at our institution (a tertiary cancer center) during a 25-month period. The radiology information system was then searched for any additional confirmatory radiologic examinations performed within 2 days after a negative finding on CT angiography. Medical records were reviewed to determine whether anticoagulation therapy was started or continued despite a negative finding on CT angiography. RESULTS: Two hundred seventy-six CT angiograms were obtained in 260 oncology patients who were clinically suspected of having pulmonary embolism. The findings from 203 CT angiograms (74%) were interpreted as negative; 56 (20%), as positive; and 17 (6%), as equivocal for pulmonary embolism. Fifty-eight patients (21%) with negative findings on CT angiography subsequently underwent additional imaging, the results of which were potentially clinically important in 6% of the patients. Six patients began to receive and two continued to undergo anticoagulation therapy despite negative findings on CT angiography; three of the six patients received anticoagulation for new-onset atrial fibrillation. CONCLUSION: Negative results of CT angiography for pulmonary embolism did not deter referring physicians from ordering other confirmatory imaging tests in 21% of patients in a high-risk oncologic population. Those additional tests rarely revealed results that might have been clinically important.