Reiichi Ishikura

Cone-Beam CT with Flat-Panel-Detector Digital Angiography System: Early Experience in Abdominal Interventional Procedures

We developed a cone-beam computed tomography (CBCT) system equipped with a large flat-panel detector. Data obtained by 200° rotation imaging are reconstructed by means of CBCT to generate three-dimensional images. We report the use of CBCT angiography using CBCT in 10 patients with 8 liver malignancies and 2 hypersplenisms during abdominal interventional procedures. CBCT was very useful for interventional radiologists to confirm a perfusion area of the artery catheter wedged on CT by injection of contrast media through the catheter tip, although the image quality was slightly degraded, scoring as 2.60 on average by streak artifacts. CBCT is space-saving because it does not require a CT system with a gantry, and it is also time-saving because it does not require the transfer of patients.

Clinicoradiological factors influencing the reversibility of posterior reversible encephalopathy syndrome : a multicenter study

PurposeThe aim of this retrospective study was to clarify the relation between the reversibility of posterior reversible encephalopathy syndrome (PRES) with three factors: the anatomical region of the brain involved, the background clinical cause, and the diffusion weighted image (DWI) intensity of PRES lesions.Material and methodsThis multicenter study, conducted by the PRES Study Group of the Neuroradiology Workshop, involved 52 cases from 28 institutions. Initial and follow-up magnetic resonance imaging were compared regarding the reversibility of PRES lesions according to anatomical location and clinical background. Initial DWI and apparent diffusion coefficient (ADC) maps were reviewed in 20 cases.ResultsReversibility was significantly lower (P < 0.01) in the brain stem (44%) and deep white matter (47%) compared to the other cortical and subcortical areas (76%–91%). The reversibility was greater in the eclampsia subgroup followed by the hypertension and chemotherapy subgroups. DWI, even with ADC maps, had limitations in predicting the outcome of PRES lesions.ConclusionThe typical cortical and subcortical PRES lesions showed reversibility, whereas the brain stem and deep white matter lesions showed less reversibility. PRES due to eclampsia showed maximum reversibility compared to hypertension- and drug-related PRES. DWI, even with ADC maps, had limitations in predicting the course of PRES.

Evaluation of vascular supply with cone-beam computed tomography during intraarterial chemotherapy for a skull base tumor.

A cone-beam lowers the X-ray exposure level and the contrast material dose used compared to those for the conventional angiography-computed tomography (angio-CT) technique. Herein we present a patient with a metastatic skull base bone tumor in which the subtraction image of cone-beam CT with a flat panel detector was useful for evaluating the vascular supply during superselective intraarterial chemotherapy. Although the image quality of cone-beam CT is poorer than that of conventional angio-CT, the cone-beam CT system is sufficient for clinical use.

Potential of superparamagnetic iron oxide in the differential diagnosis of metastasis and inflammation in bone marrow: experimental study.

Rationale and Objectives:The utility of ferucarbotran for the diagnosis of bone metastases was investigated using tumor-implanted rabbits. The potential of ferucarbotran in the differential diagnosis of metastasis and inflammation was also investigated. Methods:Twelve rabbits were divided into 2 groups (tumor and inflammation groups). Six rabbits of tumor group were inoculated with VX2 tumor cell suspension, and the 6 rabbits of the inflammation group were inoculated with 10% croton oil in the bone marrow of the right femur. All rabbits were imaged using a clinical MRI system. Signal intensity in the bone marrow of the right femur was measured in each rabbit before and after the intravenous injection of 8 &mgr;mol Fe/kg of ferucarbotran. As a control, the signal intensity in the bone marrow of the left femur (the normal, intact femur) was measured in each rabbit. The change in signal intensity of each group was compared statistically. After MRI imaging, the femora were removed, and sections were prepared for microscopic examination. Results:Signal intensity in the right femur of the tumor group did not change after injection, although that of the inflammation group and the control group decreased. In the histologic findings, tumors were widely spread in the right femur of the tumor group. The infiltration of pseudoeosinocytes was induced in the right femur of the inflammation group. Conclusions:This animal study showed that ferucarbotran was useful to detect bone marrow tumors. In addition, ferucarbotran may have potential in the differential diagnosis of bone metastasis and some kinds of inflammation.

Automated fuzzy logic based skull stripping in neonatal and infantile MR images

Automated morphometric analysis using human brain magnetic resonance (MR) images is an effective approach to investigate the morphological changes of the brain. However, even though many methods for adult brain have been studied, there are few studies for infantile brain. Same as the adult brain, it is effective to measure cerebral surface and for quantitative diagnosis of neonatal and infantile brain diseases. This article proposes a skull stripping method that can be applied to the neonatal and infantile brain. The proposed method can be applied to both of T1 weighted and T2 weighted MR images. First, the proposed method estimates intensity distribution of white matter, gray matter, cerebrospinal fluid, fat, and others using a priori knowledge based Bayesian classification with Gaussian mixture model. The priori knowledge is embedded by representing them with fuzzy membership functions. Second, the proposed method optimizes the whole brain by using fuzzy active surface model, which evaluates the deforming model with fuzzy rules. The proposed method was applied to 26 neonatal and infantile subjects between −4 weeks and 4 years 1 month old. The results showed that the proposed method stripped skull well from any neonatal and infantile MR images.

Fuzzy-ASM Based Automated Skull Stripping Method from Infantile Brain MR Images

Automated stripping of skulls from infantile brain MR images is the fundamental work to visualize cerebral surface and to measure cerebral volumes. They are important to evaluate cerebral diseases because most cerebral diseases cause morphometric changes in cerebrum. This study proposes a novel image segmentation method based on fuzzy rule-based active surface model. The proposed method was validated by applying it to two neonatal (3W and 4W) and six infantile (5W to 4Y2M) subjects. The mean sensitivity was 98.84 %, and false-positive rate was 1.21 %, and the cerebral surface was visualized well.

Arterial chemoradiotherapy for carcinomas of the external auditory canal and middle ear

The purpose of this study was to estimate the efficacy of superselective arterial chemoradiotherapy for locally advanced carcinomas of the external auditory canal and middle ear.

Serial fetal magnetic resonance imaging of cloacal exstrophy

Cloacal exstrophy (CE) is a rare congenital malformation involving the urinary, intestinal, and genital systems. We present a case of CE in which characteristic findings were detected at two serial fetal magnetic resonance imaging (MRI) sessions. At 18 weeks’ gestation, the initial fetal MRI revealed a cystic mass protruding from the infra-umbilical abdominal wall. During fetal development, the cystic mass disappeared, and an omphalocele and heterogeneous soft tissue mass were recognized at 28 weeks’ gestation. The bladder was not visualized on either examination. CE can be diagnosed by prenatal MRI, thereby permitting prenatal counseling and appropriate postnatal management.

Transcatheter arterial embolization in hepatoma complicated with obstructive jaundice

Transcatheter arterial embolization was performed on a patient with hepatoma complicated by obstructive jaundice after the patients condition had been improved by percutaneous biliary drainage. As a result of the embolization, a reduction in size was observed in both the main tumor and the tumor that had invaded the common bile duct. Even after removing the biliary drainage tube, there was no recurrence of obstructive jaundice for 6 months.

Neonatal Brain Age Estimation Using Manifold Learning Regression Analysis

The neonatal cerebral disorders severly languish the quality of life (QOL) of patients and also their families. It is required to detect and cure in their early stage for the sake of decreasing the degree of symptoms. However, it is difficult to evaluate neonatal brain disorders based on morphological analysis because the neonatal brain grows quickly and the brain development progress is different from person to person. Previously, we proposed a method of calculating growth index using Manifold learning. The growth index is effective to evaluate the brain morphological development progress, although, it does not directly correspond to the brain development delay. To evaluate brain development delay, this paper proposes an estimation method of neonatal brain age using Manifold learning, principal component analysis, and multiple regression model. The regression model is trained using a 4-D standard brain, which is constructed using training subjects with growth index. To evaluate the proposed method, we constructed a multiple regression model using 11 normal subjects (revised age: 0-4 month old), and estimated brain age of 4 normal subjects. And, we estimated brain age of 4 abnormal subjects to evaluate the detection accuracy of brain development abnormality. The results showed that the method found the differences of brain development for abnormal subjects.