Evaluation of small ischemic lesions after carotid artery stenting: the usefulness of thin-slice diffusion-weighted MR imaging.

INTRODUCTION: There has been concern regarding the usefulness of diffusion-weighted imaging (DWI) to evaluate the ischemic lesions associated with carotid artery stent placement (CAS). Some small lesions may be detected not by standard DWI but by thin-slice DWI alone, since most of the cerebral lesions are very small in size and clinically silent. The purpose of this study is to compare the detectability of the small ischemic lesions after CAS by standard and thin-slice DWI. METHODS: Both standard DWI with slice thickness of 6 mm and thin-slice DWI with slice thickness of 2 mm were obtained at the same MR examination within 2 to 7 days after 20 procedures of CAS in 17 patients. Number and measured diameter size of the detected lesions on both DWI were compared. RESULTS: All CAS procedures in 17 patients were successfully completed. The focal ischemic lesions were detected in 14 of 20 on thin-slice DWI and seven examinations on standard DWI. The total numbers of hyperintense lesions were 31 on thin-slice DWI and ten on standard DWI (p < 0.001). The sizes of these ten lesions on thin-slice DWI were larger than those of standard DWI, and the mean size of the thin-slice DWI and that of standard DWI were significantly different (p < 0.005). CONCLUSION: Thin-slice DWI was able to detect small cortical lesions better than standard DWI. Thin-slice DWI may be useful to evaluate small silent ischemic lesions after CAS.

Initial experience with computed tomography and fluoroscopically guided placement of push-type gastrostomy tubes using a rupture-free balloon catheter.

The purpose of this study was to evaluate the safety and feasibility of percutaneous radiologic gastrostomy placement of push-type gastrostomy tubes using a rupture-free balloon (RFB) catheter under computed tomography (CT) and fluoroscopic guidance. A total of 35 patients (23 men and 12 women; age range 57-93 years [mean 71.7]) underwent percutaneous CT and fluoroscopically guided gastrostomy placement of a push-type gastrostomy tube using an RFB catheter between April 2005 and July 2008. Technical success, procedure duration, and complications were analyzed. Percutaneous radiologic gastrostomy placement was considered technically successful in all patients. The median procedure time was 39±13 (SD) min (range 24-78). The average follow-up time interval was 103 days (range 7-812). No major complications related to the procedure were encountered. No tubes failed because of blockage, and neither tube dislodgement nor intraperitoneal leakage occurred during the follow-up period. The investigators conclude that percutaneous CT and fluoroscopically guided gastrostomy placement with push-type tubes using an RFB catheter is a safe and effective means of gastric feeding when performed by radiologists.

Computed tomography enteroclysis for recurrent severe gastrointestinal bleeding in a patient with vascular malformation of the small bowel.

This is a case study of a 66-year-old woman who had a vascular malformation of the small bowel that was visualized on computed tomography enteroclysis (CTE). She presented with repeated tarry stool and severe anemia. Although the source of bleeding was not identified on upper and lower gastrointestinal endoscopy, active bleeding was revealed by capsule endoscopy in the deep jejunum. The cause of bleeding was not found on capsule endoscopy. CTE was requested as double-balloon endoscopy would have been difficult because of strong adhesion of the small intestine. A continual subtle vascular malformation of the jejunum, starting from the third jejunal branch end, was demonstrated on CTE with dynamic contrast enhancement. Because this vascular malformation was considered the cause of small intestinal bleeding, selective arterial coil embolization was performed. After embolization, the repeated tarry stool disappeared and the severe anemia dramatically improved. CTE may be a safe and useful method for determining the cause of small intestinal bleeding and for subsequent therapy.

Hepatocellular lesions with increased iron uptake on superparamagnetic iron oxide-enhanced magnetic resonance imaging in cirrhosis or chronic hepatitis: comparison of four magnetic resonance sequences for lesion conspicuity.

PURPOSE: The aim of this study was to determine the adequate MR sequence for the lesion conspicuity of hepatocellular lesions with increased iron uptake on superparamagnetic iron oxide (SPIO)-enhanced MRI. MATERIALS AND METHODS: SPIO-enhanced MRI was performed using a 1.5-T system. Among 25 patients with hypovascular hepatocellular nodules on contrast-enhanced dynamic CT (no early enhancement at arterial phase and hypoattenuation at equilibrium phase), 39 lesions with increased iron uptake on SPIO-enhanced MRI were evaluated. SPIO-enhanced MRI included (1) T1-weighted in-phase gradient recalled echo (GRE) images, (2) T2-weighted fast spin echo (FSE) images, (3) T2*-weighted GRE with moderate TE (7 ms) and (4) long TE (12 ms). The lesion-to-liver contrast-to-noise ratios of the hepatocellular nodule and the signal-to-noise ratio (SNR) of the hepatic parenchyma were calculated by one radiologist for a quantitative assessment. MR images were reviewed retrospectively by two independent radiologists to compare the subjective lesion conspicuity in each image set based on a four-point rating scale. RESULT: The mean lesion-to-liver contrast-to-noise ratios with T2*-weighted GRE with moderate TE (7 ms) was highest (5.79+/-3.71) and was significantly higher than those with T1-weighted, in-phase images (3.79+/-3.23, P<.01), T2-weighted images (2.72+/-1.52, P<.001) and T2*-weighted GRE with long TE (12 ms) (3.93+/-2.69, P<.05). The subjective rating of lesion conspicuity was best on the T2*-weighted GRE with moderate TE (7 ms), followed by that on the T2*-weighted GRE with moderate TE (7 ms; P<.05). CONCLUSION: T2*-weighted GRE sequence with moderate TE (7 ms) showed high lesion-to-liver contrast-to-noise ratios in hepatocellular lesions with increased iron uptake on SPIO-enhanced MRI, indicating better lesion conspicuity of hypointense hepatocellular nodules in cirrhosis or chronic hepatitis.

Iodized oil accumulation in hypervascular hepatocellular carcinoma after transcatheter arterial chemoembolization: comparison of imaging findings with CT during hepatic arteriography.

PURPOSE: To compare the degree of tumor enhancement seen on computed tomography (CT) during hepatic arteriography (CT/HA) performed before transcatheter arterial chemoembolization (TACE) versus that determined based on the accumulation of iodized oil seen on CT images obtained after TACE in patients with hypervascular hepatocellular carcinoma (HCC) and evaluate the discrepancy in findings between the two imaging modalities (more or less oil accumulation after TACE compared with enhancement on CT/HA). MATERIALS AND METHODS: CT/HA, TACE, and iodized oil CT after TACE were performed in 69 patients with 83 hypervascular HCCs with use of an interventional CT system. The degree of contrast enhancement of the lesion on CT/HA and the iodized oil accumulation on unenhanced CT after TACE were compared. RESULTS: Among 83 HCCs, the degree of enhancement on CT/HA before TACE corresponded to the iodized oil accumulation on CT in 56 (67.5%). Fifteen of 83 HCCs (18%) showed incomplete or poor accumulation of iodized oil despite good enhancement on CT/HA images. Twelve of 83 HCCs (14.5%) showed moderate or complete accumulation of iodized oil despite poor or no enhancement on CT/HA images. In particular, in two patients with occluded portal veins, iodized oil did not accumulate in the tumor despite good visualization on CT/HA. CONCLUSIONS: Although iodized oil accumulation in hypervascular HCCs correlates with the degree of lesion enhancement on CT/HA in most cases, a discrepancy may occur in a substantial number of cases, which likely affects the prediction of therapeutic effects in hypervascular HCCs.

[Chemoradiotherapy for neurohypophyseal immature teratoma].

We performed chemoradiotherapy for two patients (aged 6 and 33 years)with neurohypophyseal immature teratoma. The patients received total doses of 40 to 50.6 Gy with concurrent carboplatin and etoposide. In both cases, neurological symptoms improved. Both patients are still alive and remain free from local recurrence and distant metastasis 92 months and 62 months, respectively, after the completion of chemoradiotherapy. No late complications were observed. Chemoradiotherapy is extremely effective in the treatment of neurohypophyseal immature teratoma.