Koichi Ishiyama

Small veins entering the liver

Abstract. It is important to recognize and understand focal fatty infiltration and pseudolesions of the liver mimicking liver tumors on CT during arterial portography or helical-CT images. These conditions are caused by venous flow outside the main portal vein. Unless this is borne in mind, incorrect diagnosis and management may follow. This article demonstrates the appearance of the parenchymal changes caused by systemic venous flow and location of the systemic veins entering the liver parenchyma.

CT Features of Pancreatic Fistula After Pancreaticoduodenectomy

OBJECTIVE Our objective was to establish the CT features that are indicative of pancreatic fistula after pancreaticoduodenectomy. CONCLUSION A fluid collection seen on CT around the pancreaticojejunostomy site and in the pancreatic bed may be caused by pancreatic fistula in patients who have undergone pancreaticoduodenectomy. CT depiction of air bubbles in the fluid at these sites may strongly suggest the diagnosis of pancreatic fistula.

Reduced perfusion reserve in Leukoaraiosis demonstrated using acetazolamide challenge 123I-IMP SPECT.

Objective: We examined the relationship between the perfusion reserve as measured by acetazolamide (ACZ)-challenge N-isopropyl-I-123-p-iodoamphetamine (IMP)-single-photon emission computed tomography (SPECT) and the degree of leukoaraiosis (LA) as estimated using magnetic resonance imaging. Methods: In 51 patients receiving 123IMP-SPECT with the resting state and ACZ challenge, the unaffected cerebral hemispheres were included in the present study. Mean cerebral blood flow (CBF) in the resting state and ACZ reactivity were acquired. Absolute CBF value and ACZ reactivity were compared among patients with LA grades 0, 1, and 2. The relationship between mean age and LA grade was also assessed. Results: No significant difference in the absolute CBF value in the resting state was observed among the 3 LA groups. Although vasoreactivity in LA grade 0 did not differ from that in grade 1, vasoreactivity in LA grade 2 was significantly lower (P < 0.05) than that in grades 0 or 1. Conclusions: The perfusion reserve is impaired in advanced LA.

Visualization of lymphatic basin from the tumor using magnetic resonance lymphography with superparamagnetic iron oxide in patients with thoracic esophageal cancer.

Objective: To evaluate magnetic resonance (MR) lymphography with submucosal injection of superparamagnetic iron oxide (SPIO) for imaging lymphatic pathways from thoracic esophageal cancer. Methods: In 24 patients with esophageal cancer, SPIO was injected into the submucosal layer of the peritumoral region endoscopically and MR lymphography was conducted. In study 1, fast spoiled gradient-recalled acquisition using a steady-state (FSPGR) sequence was performed from the neck to the upper abdomen before and at 20, 40, and 60 minutes after injection in 10 patients. In study 2, FSPGR and spin echo T1-weighted images were obtained after injection in 14 patients. Areas scanned were the neck to the upper mediastinum and the upper abdomen. Results: In study 1, at 20 minutes after injection, the signal of each lymph node appeared attenuated when compared with precontrast images. The signal-to-noise ratio in lymph nodes exhibiting influx of SPIO was significantly lower than that found on precontrast images (P < 0.0005). In study 2, influx to the neck lymph nodes was detected in 8 patients (64.3%), whereas influx to the upper abdominal lymph nodes was detected in 13 (92.9%). Conclusions: Magnetic resonance lymphography with SPIO could visualize the lymphatic pathways draining from the injection site and the location of lymph nodes exhibiting influx of SPIO in patients with thoracic esophageal cancer.

Tumor-liver contrast and subjective tumor conspicuity of respiratory-triggered T2-weighted fast spin-echo sequence compared with T2*-weighted gradient recalled-echo sequence for ferucarbotran-enhanced magnetic resonance imaging of hepatic malignant tumors

To compare respiratory‐triggered T2‐weighted fast spin‐echo (RTT2W‐FSE) and gradient T2*‐weighted recalled‐echo (T2*W‐GRE) images for visualization of malignant hepatic tumors using ferucarbotran‐enhanced magnetic resonance (MR) imaging.

Correlation between severity of carotid stenosis and vascular reserve measured by acetazolamide brain perfusion single photon emission computed tomography.

Few studies have investigated the relationship between the degree of stenosis of the internal carotid artery (ICA) and cerebrovascular reserve (CVR). This study examined that relationship. A total of 56 ICAs in 43 patients were included. Computed tomography scan or magnetic resonance imaging showed no evidence of infarction in any of these patients. Both iodine-123-N-isopropyl-p-iodoamphetamine ((123)IMP)-single photon emission computed tomography (SPECT) in the resting state and (123)IMP-SPECT with acetazolamide (ACZ) enhancement were performed. Quantitated cerebral blood flow (CBF) images were acquired with the (123)IMP autoradiography technique. The mean CBF without ACZ administration (resting CBF) and CVR in the middle cerebral artery territory were calculated using stereotactic extraction estimation (SEE) analysis software. The degree of stenosis in the origin of the ICA was calculated from intra-arterial digital subtraction angiography. Resting CBF was not correlated with the degree of ICA stenosis; however, nonlinear regression analysis (second-order equation) showed a moderate correlation between CVR and the degree of ICA stenosis. In 72% of the cases with a CVR <30%, ICA stenosis was >74%. Using the SEE method, CVR was moderately correlated with the degree of ICA stenosis. Our findings indicate that evaluating CVR by ACZ-enhanced (123)IMP-SPECT in patients with ICA stenosis is of clinical value.

F-18 fluorodeoxyglucose positron emission tomography for differential diagnosis of pancreatic tumors

Positron emission tomography with 2-deoxy-2-[18F]fluoro-D-glucose (FDG-PET) has been proven useful for differentiating pancreatic ductal cancer from mass-forming chronic pancreatitis. However, there are particular pancreatic tumors having various grades of malignancy such as intraductal papillary mucinous neoplasm (IPMN) or pancreatic neuroendocrine tumor. We examined whether the cut-off value of maximum standardized uptake value (SUVmax) determined by pancreatic ductal cancers is also applicable for other pancreatic tumors.One hundred thirty six patients with pancreatic tumors underwent FDG-PET imaging. We first analyzed the cut-off value to differentiate pancreatic ductal cancers from mass-forming chronic pancreatitis. Secondly, we determined the cut-off value between malignant IPMN and benign IPMN. Thirdly, we computed a cut-off value between malignant pancreatic tumors and benign tumors irrespective of tumor type.The optimal cut-off value to differentiate ductal cancers from mass-forming chronic pancreatitis was 2.5. The optimal cut-off value for differentiating malignant IPMN from benign IPMN was also 2.5, similar to that of reported studies. In all types of pancreatic tumors, the cut-off value was also 2.5. The accuracy for detecting malignancy was 93.4% for all tumors.In the FDG-PET study for pancreatic tumors, an SUVmax of 2.5 would be justified as a cut-off value to differentiate malignant lesions.

Spinal hyperostosis as an important sign indicating spine injuries on postmortem computed tomography

Although spine injuries are not always detectable on postmortem computed tomography (PMCT), spinal hyperostosis, an important risk factor for spine injury, is relatively easily detectable on PMCT. We therefore examined the utility of the detection of spinal hyperostosis on PMCT as an indicator of spine injury. Full-body PMCT images of 88 autopsy cases with a bruise on the face or forehead but no identifiable skull fracture were reviewed prior to autopsy for the identification and classification of spinal hyperostosis. Spine injuries were observed in 56.0% of cases with spinal hyperostosis and 1.6% of cases without spinal hyperostosis. Among the cases with spinal hyperostosis, spine injuries were observed in 66.7% of cases at stage 2 or 3 and in 88.9% of cases at stage 3. Spine injuries were diagnosed on PMCT in 33.3% of cases prior to autopsy. A significant association was found between spinal hyperostosis and presence of spine injury that cannot be detected on PMCT, indicating that the identification of spinal hyperostosis on PMCT may assist in detecting spine injuries. This finding suggests that investigation of the presence of spine injury based on the identification of spinal hyperostosis on PMCT may assist in determining the correct cause of death by autopsy.

Evaluating benign and malignant musculoskeletal lesions with radionuclide angiography and SPECT using Tc-99m MIBI.

Purpose: The purpose of this study was to evaluate the use of radionuclide angiography and single photon emission computed tomography (SPECT) using Tc-99m hexakis-2-methoxyisobutylisonitrile (Tc-99m MIBI) for analyzing musculoskeletal lesions. Materials and Methods: Radionuclide angiography and SPECT using Tc-99m MIBI were performed in 36 patients with various soft tissue and bone pathologies (18 benign and 18 malignant lesions). The ratio of the counts of the lesion to that of the contralateral normal area was calculated from the region of interest drawn on the MIBI scan. The MIBI-uptake ratio was calculated using SPECT and the MIBI-perfusion index was calculated using radionuclide angiography. Results: The MIBI-uptake ratio in malignant lesions (4.80 ± 4.43) was significantly higher (P < 0.05) than that in benign lesions (1.83±2.48). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the MIBI-uptake ratio for malignant lesions were 72%, 83%, 78%, 81%, and 75%, respectively. The MIBI-perfusion index in malignant lesions (17.68 ± 21.19) was significantly higher (P < 0.05) than that in benign lesions (2.25 ± 2.56). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the MIBI-perfusion index for malignant lesions were 87%, 75%, 81%, 77%, and 86%, respectively. Conclusions: The MIBI-uptake ratio and MIBI-perfusion index using Tc-99m MIBI can yield important additional information with which to differentiate musculoskeletal lesions.

Efficacy of combined balloon-occluded retrograde transvenous obliteration and simultaneous endoscopic injection sclerotherapy.

OBJECTIVE We evaluated the efficacy and safety of balloon-occluded retrograde transvenous obliteration (B-RTO) performed using absolute ethanol with iodized oil (ET+LPD) and simultaneous endoscopic injection sclerotherapy (EIS) with cyanoacrylate (CA) for gastric varices (GVs). METHODS A total of 16 patients with endoscopically proven high-risk GVs treated using combined B-RTO with ET+LPD and EIS with CA between January 2007 and July 2012 were enrolled. RESULTS Twelve cases included GVs involving both the cardia and fundus, two cases included fundal varices and two cases included cardiac varices. In terms of the form of GVs, 10 cases involved F2 lesions and six cases involved F3 lesions. The flow vein was the left gastric vein in 13 cases and the posterior gastric vein in three cases. The drainage route was a splenorenal shunt in all cases. The average dose of ET+LPD was 12.0 mL, while that of CA was 2.45 mL. All complications were transient, and no major complications occurred after the procedures. None of the patients experienced bleeding or recurrence of gastric varices after the combined B-RTO and EIS procedures during an average follow-up period of 38.3 months. CONCLUSION Combined B-RTO with ET+LPD and simultaneous EIS with CA is considered to be an effective and safe procedure for treating GVs.