Biomedical subjects
Yuichi Inoue
Publications and source records attributed to Yuichi Inoue.
Radiofrequency ablated lesion in the normal porcine lung: long-term follow-up with MRI and pathology.
PURPOSE: To evaluate the effectiveness of magnetic resonance imaging (MRI) in reflecting histopathologic changes after radiofrequency ablation (RFA) to the lung and to assess accurately the extent of tissue necrosis for evaluating untreated lesions. METHODS: Percutaneous RFA was performed on 72 lung regions in 12 pigs under computed tomographic guidance. After performing MRI, the animals were divided into three experimental phases: in the acute phase, 4 pigs were killed immediately after the procedure; in the subacute phase, 4 pigs were killed at 1 week; and in the chronic phases, 2 pigs were killed at 4 and 8 weeks after the procedure, respectively. MRI-histopathologic correlation was performed. RESULTS: In the acute phase, the inner zone showed hypointensity on T2-weighted images and isointensity on T1-weighted images, with a lack of enhancement on contrast-enhanced T1-weighted images, representing early changes in coagulative necrosis on histopathologic examination. The outer zone showed hyperintensity on T2-weighted images and isointensity on T1-weighted images, with ring-like enhancement on contrast-enhanced T1-weighted images. The histopathologic section showed alveolar fluid collections and congestion. In the subacute phase the MR zone pattern was essentially similar to that of the acute phase, but the ablated lesion showed extensive coagulative necrosis with a fibrovascular rim on histopathologic examination. In the chronic phase, there was no change in the zone pattern on MRI. The lesions showed gradual resorption of coagulative necrosis. The area of coagulative necrosis correlated closely with the histopathologic size (p < 0.05). CONCLUSIONS: MRI effectively visualized the histopathologic changes after RFA and accurately determined the extent of the necrotic lesion. MRI is potentially a useful modality for evaluating therapeutic efficacy after RFA to the lung.
Dual balloon-occluded retrograde transvenous obliteration of gastric varix draining into the left adrenal vein and left inferior phrenic vein.
A 66-year-old woman with a gastric varix, draining into a dilated left adrenal vein and a left inferior phrenic vein, was treated with dual balloon-occluded retrograde transvenous obliteration (B-RTO). Under balloon occlusion of the left adrenal vein and the left inferior phrenic vein, retrograde injection of a sclerosant (5% ethanolamine oleate) into the gastric varix was performed. Two weeks later, disappearance of flow in the gastric varix was confirmed on endoscopic ultrasound examination.
Detection of portal perfusion abnormalities: comparison of 3 ferucarbotran-enhanced magnetic resonance imaging sequences.
OBJECTIVE: To estimate the accuracy, sensitivity, and specificity of 3 ferucarbotran-enhanced magnetic resonance (MR) imaging sequences prospectively for the detection of nontumoral portal perfusion abnormalities. METHODS: Thirty-nine noncirrhotic patients with liver metastases underwent computed tomography during arterial portography (CTAP) and MR imaging comprising T1-weighted gradient recalled echo (GRE), T2-weighted fast spin echo (FSE), and T2*-weighted GRE sequences with and without ferucarbotran. Magnetic resonance images were reviewed by 4 blinded observers for rating based on the confidence scale. The accuracy, sensitivity, and specificity for each sequence were measured by receiver operating characteristic analysis. Contrast-to-noise ratio (CNR) and relative signal-to-noise ratio changes were statistically compared. RESULTS: Thirty-nine nontumoral perfusion defects were observed in 22 patients by CTAP. Receiver operating characteristic analysis showed the accuracy was higher for T2*-weighted GRE (0.884) than for T1-weighted GRE (0.572) and T2-weighted FSE (0.597). T2*-weighted imaging achieved the highest sensitivity (81.4%) and the lowest specificity (86.6%). Postenhanced T2*-weighted imaging achieved the highest CNR (19.3 +/- 9.2). CONCLUSIONS: T2*-weighted imaging was the most accurate and sensitive method for detecting portal perfusion abnormalities compared with T1- or T2-weighted imaging, whereas T1- or T2-weighted imaging is superior in specificity to T2*-weighted imaging during ferucarbotran-enhanced MR imaging.
Risperidone withdrawal-related respiratory dyskinesia: a case diagnosed by spirography and fibroscopy.
Risperidone is a frequently used member of a new class of atypical antipsychotics-the serotonin-dopamine antagonists (SDAs)-due to its comparatively high efficacy and low D2/5HT2 binding ratio, which results in a low incidence of extrapyramidal side effects including tardive dyskinesia (TD). The authors present an elderly patient with mixed dementia who developed TD at multiple sites, (including respiratory dyskinesia [RD], limb dyskinesia, and orofacial dyskinesia) following abrupt withdrawal of risperidone therapy. RD is not a rare condition, but is often misdiagnosed and is potentially lethal. Therefore, clinicians should pay close attention to possible onset of RD in patients with multiple risk factors for TD, even when SDA therapy is used. If RD is suspected, assessment should include spirography combined with fibroscopy for examination of irregularities in the rate, rhythm, and depth of respiration.
The influence of radiofrequency ablation on hepatic vessels in porcine liver.
BACKGROUND/AIMS: The objective of this study was to clarify the influence of radiofrequency ablation on the portal and hepatic vein. METHODOLOGY: Hepatic radiofrequency ablation was performed on 18 swine (mean weight, 22 kg). The livers were removed immediately, 1 week or 3 weeks following ablation. Vessel patency and diameter were determined by computed tomography, and the severity of endothelial injuries was determined histopathologically. RESULTS: The patency rate for portal and hepatic veins with diameters less than 3.0 mm decreased sequentially. At three weeks following ablation, the patency rate for vessels with diameters more than 3.0 mm was significantly higher (P<0.05) compared to those with diameters less than 2.0 mm. In portal and hepatic veins contiguous to ablated hepatic parenchyma, the endothelium with intimal thickening was found at 1 to 3 weeks following ablation, although its detection rate was decreased until 3 weeks. CONCLUSIONS: The portal and hepatic vein with diameters more than 3.0 mm in radiofrequency lesions maintained high patency. The endothelium seems to play an important role for maintaining vessels patency and the distal hepatic tissue following ablation. We believe that this maintained vascular patency may be the advantage of radiofrequency ablation over the PEIT.