Toshiyuki Irie

Real-time Virtual Sonography for navigation during targeted prostate biopsy using magnetic resonance imaging data.

Objectives:  To evaluate the effectiveness of the medical navigation technique, namely, Real‐time Virtual Sonography (RVS), for targeted prostate biopsy.

Contrast-enhanced CT with saline flush technique using two automated injectors: how much contrast medium does it save?

Purpose The purpose of this work was to investigate the volume of contrast medium saved by the saline flush technique. Method Thoracic helical CT was performed by injecting 75 ml of contrast material (Ioversol 320) only (n = 25; Group A) or 75 ml of contrast medium pushed with 6 ml (n = 25; Group B), 12 ml (n = 25; Group C), 25 ml (n = 25; Group D), or 50 ml (n = 25; Group E) of saline at a rate of 2 ml/s. The aortic CT numbers were measured from 30 to 55 s after the beginning of injection. We compared the time to peak aortic enhancement (TPAE) among Groups A–E. Results The TPAEs of the Groups A–E were 42.6, 45.2, 48.6, 48.4, and 48.3 s, respectively, and there was a statistically significant difference among them (p < 0.0001, analysis of variance). Post hoc test revealed statistically significant differences in TPAE between Groups A and B, C, D, and E and between Groups B and C, D, and E but no differences among Groups C, D, and E. Conclusion The saline flush technique prolongs TPAE by 6 s and saves 12 ml of contrast medium.

Biopsy of Lung Nodules with Use of I-I Device Under Intermittent CT Fluoroscopic Guidance: Preliminary Clinical Study

PURPOSE To investigate the efficacy of computed tomography (CT) fluoroscopy and a new needle holder (the I-I device) in lung nodule biopsy. MATERIALS AND METHODS The I-I device is made of acrylate resin and was used to keep the entire needle in the tomographic plane. This study consisted of biopsies of 79 lung nodules in 77 patients. The final diagnoses were malignant in 54 patients, benign in 23, and unconfirmed in two. The biopsy procedure time from the beginning of the CT fluoroscopy procedure to the removal of the needle was measured for 24 needle passes. The radiation dose on the physicians hand was measured in five cases with use of a thermoluminescence ring. RESULTS Fifty-one malignant and 20 benign lesions were correctly diagnosed with histologic specimens (90%). In 58 of 77 patients (75%), the biopsy procedures were completed within a single breath-hold. Pneumothorax occurred in 20 of 77 patients (26%) and chest tube insertion was required in five. The incidence of pneumothorax was significantly lower in patients who held their breath during biopsy procedures compared with those who did not (P < .0001; chi2 test). The biopsy procedure time ranged from 15 to 39 seconds (mean: 28.2 sec). The mean radiation dose on the physicians hand was 2 mSv/case. CONCLUSION The diagnostic accuracy of biopsy with use of the I-I device under CT fluoroscopic guidance is comparable with that of the conventional method; however, a combination of CT fluoroscopy and the I-I device enables rapid biopsy procedures.

Retrievable IVC Filter: Preliminary in Vitro and in Vivo Evaluation

PURPOSE To develop an inferior vena cava (IVC) filter that is retrievable even after neointimal formation and incorporation into the caval wall. MATERIALS AND METHODS Eight filters were placed percutaneously in the infrarenal IVC of eight dogs. Four weeks after placement, percutaneous retrieval of the filters was attempted. Vena cavograms were obtained before and immediately after retrieval. Three dogs were killed immediately after the retrieval procedure was completed. In the other five dogs, follow-up vena cavography was performed 4-14 weeks after retrieval, and autopsy was performed. RESULTS The filters were placed and retrieved successfully in all eight dogs. No migration, caval penetration, or tilting occurred. The IVCs were completely patent both before and immediately after retrieval in all eight dogs. In the three dogs killed immediately after retrieval, neointimal hyperplasia was seen around the struts, but there was no detachment. Delayed stenosis was not seen in any of the five dogs that were followed up, and the inner surface of the caval wall was smooth. CONCLUSION This IVC filter can be easily placed and safely retrieved percutaneously, even after neointimal formation.

Influence of liver cirrhosis on pseudolesions in liver at CT during arterial portography.

PURPOSE Pseudolesions are sometimes seen around the falciform ligament, around the gallbladder, or at the posterior edge of the medical segment on CT during arterial portography. The purpose of this study was to investigate the influence of liver cirrhosis on these pseudolesions. METHOD The basis of this study was 33 patients with liver cirrhosis or hepatitis (group A) and 43 with neither (group B). The standard for diagnosis was surgical findings. We investigated whether there was a difference in the frequency of each pseudolesion between groups A and B. When tumors were seen in each location, they were excluded from statistical analysis. RESULTS Pseudolesion around the falciform ligament was seen in none of 32 patients in group A and in 18 of 40 in group B (4 cases were excluded), around the gallbladder in 14 of 30 in group A and 16 of 42 in group B (4 cases were excluded), and at the posterior edge of the medial segment in 13 of 33 in group A and 16 of 42 in group B (1 case was excluded). There was a statistically significant difference in the frequency of pseudolesion around the falciform ligament (p < 0.001, Fisher test), but not around the gallbladder or posterior edge of the medial segment. CONCLUSION Liver cirrhosis decreases the frequency of pseudolesions around the falciform ligament, but not around the gallbladder or posterior edge of the medial segment.

Contrast-enhanced spiral CT of the liver : Effect of injection time on time to peak hepatic enhancement

PURPOSE On contrast-enhanced hepatic CT, maximum tumor detection of liver metastases from colorectal cancer is achieved at peak hepatic enhancement. We investigated the relationship between injection time of contrast medium and time to peak hepatic enhancement (TPHE) after the end of injection. METHOD One hundred nineteen patients without a cardiovascular disorder were enrolled in this study. Before the spiral CT was performed, a small amount of contrast medium was injected and a single level dynamic CT was performed to evaluate aortic enhancement and to determine the scan start time of the spiral examination. Patients were divided into three groups; contrast medium was injected over 30 s in 40 patients (Group A), 45 s in 39 patients (Group B), and 60 s in 40 patients (Group C). The TPHE after the end of injection was measured, and the difference among the groups was compared using one-way analysis of variance. A p value of <0.05 was considered a statistically significant difference. RESULTS The TPHEs of the groups were 25.3 +/- 4.6 s (Group A), 27.0 +/- 5.8 s (Group B), and 24.4 +/- 4.6 s (Group C) and were similar in value. No statistically significant difference was observed (p = 0.067). CONCLUSION Hepatic enhancement reaches its peak at approximately 25 s after the end of contrast medium injection irrespective of injection time.

Intrahepatic portosystemic venous shunts: spectrum of CT findings in external and internal subtypes.

Purpose The purpose of this work was to survey the spectrum of CT findings in intrahepatic portosystemic venous shunts (IPSVSs). Method One thousand consecutive liver CT scans examined with an enhanced helical technique were retrospectively reviewed on workstation to find IPSVSs. Results IPSVSs were noted in 37 patients and divided into two subtypes according to the location of the communicating systemic vein, either outside (external type, n = 34) or within (n = 4) the liver (one patient had both internal and external types). All the external-type shunts were noted in cases with portal hypertension (n = 34). Most shunts (n = 30) ran through segment 4 and/or 3 and came out near the falciform ligament, but five shunts were noted in segment 2 communicating either with the systemic vein (n = 3) or probably with an enlarged left gastric vein (n = 2). Solitary portohepatic venous shunts (internal type) were noted in three cases with (n = 2) or without (n = 1) aneurysmal dilatation and many portohepatic venous shunts in another patient. Conclusion IPSVSs of the external type were far common than those of the internal type, always associated with increased pressure of the portal system and in specific sites probably lacking the hepatic capsule.

Efficacy of a microballoon catheter in transarterial chemoembolization of hepatocellular carcinoma using miriplatin, a lipophilic anticancer drug: Short-term results

The goal of the study was to evaluate the efficacy and safety of balloon‐occluded transarterial chemoembolization (B‐TACE) of hepatocellular carcinoma (HCC) using miriplatin (a lipophilic anticancer drug) and gelatin particles.

Selective balloon-occluded transarterial chemoembolization for patients with one or two hepatocellular carcinoma nodules: Retrospective comparison with conventional super-selective TACE

Selective balloon‐occluded transarterial chemoembolization (B‐TACE) enables strong TACE; infusion of more volume of lipiodol emulsion and forceful injection of embolization materials. The aim of this study is to analyze the efficacy of B‐TACE for patients with one or two hepatocellular carcinoma (HCC) nodules compared with conventional super‐selective TACE using a microcatheter (C‐TACE).

New Embolization Microcoil Consisting of Firm and Flexible Segments: Preliminary Clinical Experience

PurposeTo describe the preliminary clinical experience with a new embolization microcoil.MethodsThe microcoil was made of a platinum coil spring, and consisted of firm and flexible segments. The firm segment functioned as an anchor and the flexible segment was well compacted to occlude the arteries. No Dacron fiber was attached. Seventy-one new microcoils were placed via microcatheters in 28 visceral arteries of 17 patients. Two other types of microcoils with Dacron fibers were used together in 8 arteries.ResultsSixty-nine new microcoils were placed and compacted successfully. Two coils were misplaced; one was retrieved and the other was left in the migrated artery, which remained patent 5 months later. All 28 arteries were occluded, and the goals of intervention were achieved successfully in all 17 cases.ConclusionThe new microcoils anchored and compacted well in the arteries. The clinical feasibility of this coil design was confirmed. The additional use of other types of microcoils with Dacron fiber was necessary to obtain rapid occlusion in some cases.