Kanazawa, Susumu

With the aim of sequence optimization in susceptibility-weighted imaging (SWI), 2 image acquisition parameters (slice thickness and matrix size) and 2 image processing conditions (number of slices per minimum intensity projection (MIP) and Sliding Window) were investigated using a 1.5-T magnetic resonance imaging (MRI) system. The subjects were 12 healthy volunteers and the target region for scanning was the whole brain. Informed consent was obtained from all subjects. First, susceptibility-weighted images were acquired with various slice thicknesses from 1mm to 5mm and various matrix sizes from 256x256 to 512x512, and the images were assessed in terms of the contrast-to-noise ratio (CNR) and were also visually evaluated by three radiologists. Then, the number of slices per MIP and the usefulness of the Sliding Window were investigated. In the study of the optimal slice thickness and matrix size, the results of visual evaluation suggested that a slice thickness of 3mm and a matrix size of 448x448 are optimal, while the results of evaluation based on CNR were not significant. As regards the image processing conditions, the results suggested that the number of slices per MIP should be set to a minimum value of 2 and that the use of Sliding Window is effective. The present study provides useful reference data for optimizing SWI sequences.

From January 2004 to March 2007, 308 patients with clinically localized prostate cancer were treated using iodine-125 (125I) seed implantation (permanent brachytherapy) at Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences. We evaluated the treatment’s effi cacy and morbidity in 300 prostate cancer patients who were followed up for more than 1 month after brachytherapy. Based on the National Comprehensive Cancer Network (NCCN) guidelines, patients with a prostate volume of less than 40 ml in transrectal ultrasound imaging were classifi ed as low or intermediate risk. The median patient age was 67 years (range 50 to 79 years), the median prostate-specific antigen (PSA) value before biopsy was 6.95 ng/ml (range 1.13 to 24.7 ng/ml), and the median prostate volume was 24.33 ml (range 9.3 to 41.76 ml). The median follow-up was 18 months (range 1 to 36 months) and the PSA levels decreased in almost all patients after brachytherapy. Although 194 of 300 patients (64.7%) complained of diffi culty in urination, pollakisuria/urgency, miction pain, and/or urinary incontinence, all of which might be associated with radiation prostatitis during the fi rst month after brachytherapy, these symptoms gradually improved. 125I seed implantation brachytherapy is safe and eff ective for localized prostate cancer within short-term follow up.

The differences in physiological and safety conditions of one-man buses and two-man buses were examined from the view point of occupational fatigue. This survey consisted of a work load study which included a time study, study of subsidiary behavior, auditory task, memory test, Galvanic Skin Response (GSR) and physiological function tests and a self-administered questionnaire which involved items concerning safety and subjective fatigue complaints. The visual and postural restrictions in the one-man bus were greater than in the two-man bus. The mental capacity of the one-man bus drivers was found to be less. Greater mental fatigue and stress were observed in the one-man bus. More subjective fatigue complaints were observed in the one-man bus. More cases of near accidents were observed in the one-man bus. From these results it was concluded that the one-man bus caused bus drivers a greater mental and physical work load.

The present study was performed to clarify the effect of hypertonic saline infusion into the lung parenchyma on radiofrequency ablation (RFA) of the lungs. A total of 20 ablation zones were created in 3 pigs. The ablation zones were divided into 3 groups. Group 1 (n6) consisted of ablation zones created by applying smaller radiofrequency (RF) power without saline infusion;group 2 (n5) zones were created by applying greater RF power without saline infusion;and group 3 (n9) zones were created by applying greater RF power with saline infusion. The techniques of saline infusion included administration of hypertonic saline 1ml before RFA, followed by continuous administration at a rate of 1ml/min during the first 2min after the initiation of RFA. The ablation parameters and coagulation necrosis volumes were compared among the groups. Group 3 had a tendency toward smaller mean impedance than group 1 (p0.059) and group 2 (p0.053). Group 3 showed significantly longer RF application time than group 2 (p0.004) and significantly greater maximum RF power than group 1 (p0.001) and group 2 (p0.004). Group 3 showed significantly larger coagulation necrosis volume (mean, 1,421mm3) than group 2 (mean, 858mm3, p0.039) and had a tendency toward larger necrosis volume than group 1 (mean, 878mm3, p0.077). Although this small study had limited statistical power, hypertonic saline infusion during RFA appeared to enlarge coagulation necrosis of the lung parenchyma.

Hepatic outflow obstruction created by balloon occlusion of the hepatic vein induces characteristic angiographic findings in the occluded area: prolonged enhancement on hepatogram followed by reversed portal opacification on the hepatic arteriogram and perfusion defect on the arterial portogram. The following induced hepatic hemodynamic changes are suggested: hepatic arterial flow increases, and the portal vein acts as a draining vein with slow reversed flow. These unique hemodynamic changes enhance the effect of hepatic interventional therapies. In transcatheter arterial infusion, increasing hepatic arterial flow and absence of portal inflow can bring about a high concentration of drugs, the presence of which is greatly protracted due to outflow blockage. In transcatheter arterial chemoembolization, reversed portal flow can allow portal embolization in addition to arterial embolization. In microwave coagulation therapy and radiofrequency ablation therapy, decreasing portal flow can cause larger areas of coagulation. Further, the technique of hepatic venous occlusion has potential therapeutic applications.

We investigated the diagnostic capabilities of I-131, Tl-201, and Tc-99m-MIBI (hexakis-2-methoxyisobutyl- isonitrile) scintigraphy for thyroid cancer metastases after total thyroidectomy over the entire body and for every locus before and after thyroid bed ablation. After total thyroidectomy of thyroid cancer, 36 cases were subjected to I-131 treatment 64 times. They consisted of 17 men and 19 women with 31 papillary carcinomas and 5 follicular carcinomas. Their ages were 22--75(an average of 60.5+/-12.3) years. I-131 scintigraphy(I-131), Tl-201 scintigraphy(Tl-201), and Tc-99m- MIBI scintigraphy (Tc-99m-MIBI) were performed. We defined the metastases as those cases in which serum thyroglobulin (Tg)increased significantly or in which we were able to prove the lesions on CT (computed tomography), MRI (magnetic resonance imaging) or bone scintigram. Three radiology medical specialists visually evaluated each scintigram and calculated the sensitivity, specificity, and likelihood ratio. For whole-body sensitivity, both Tl-201 and Tc-99m-MIBI were high before ablation and I-131 was high after ablation. Before ablation, the negative likelihood ratio was less than 0.1 for Tl-201 and Tc-99m-MIBI, while the positive likelihood ratio was more than 10 for Tl-201. After ablation, the positive likelihood ratio for I-131, Tl-201, and Tc-99m-MIBI was more than 10. The sensitivity of the mediastinum was appropriate, except for I-131 before ablation, and the sensitivity of the lung before and after ablation was inferior for either tracer. The specificity of the cervix for I-131 before ablation was markedly deteriorated, but it increased after ablation.

An 83-year-old man with a large internal iliac artery aneurysm (IIAA) was treated with the use of stent-graft, suggesting successful results at 3, 6, and 12 months after treatment. However, 24-month follow-up computed tomography showed minor peripheral opacification of the IIAA. The patient underwent surgical endoaneurysmorrhaphy. No previous report of long-term recanalization of a satisfactorily thrombosed iliac artery aneurysm at 2 years or more after stent-grafting has been previously reported. Further follow-up studies need to be performed on the present procedure before anyone can confidently recommend it in regard to its long-term safety.

To clarify the incidence, background, and progress of hepatic infarction following interventional procedures, cases of hepatic infarction following interventional procedures at our department during the last decade were identified by reviewing the clinical records of 1982 abdominal angiography and interventional procedures and records of abdominal CT. Nine episodes (0.5%) in 8 patients were identified as hepatic infarction following an interventional procedure. Five episodes were preceded by embolization of the hepatic or celiac artery at emergency angiography for postoperative bleeding with hemorrhagic shock. Three episodes followed the elected interventional procedure for hepatocellular carcinoma, and the remaining episode occurred after 12 months of chemoinfusion through an indwelling catheter in the hepatic artery and portal vein. Hepatic arterial occlusion in all episodes and portal venous flow abnormality in 5 episodes were observed on angiography. Four patients whose liver function was initially impaired died of hepatic infarction, although the extent of the disease on CT did not appear to be related to the mortality. Multiple risk factors, including arterial insufficiency, were observed in each patient. The incidence of hepatic infarction following interventional procedures in this series was low but sometimes fatal, and occurred most frequently in emergency embolization in hemorrhagic shock.