Toyohiko Sakai

Specific high-resolution computed tomography findings associated with sputum smear-positive pulmonary tuberculosis.

Objectives: This study aimed to evaluate whether high-resolution computed tomography (HRCT) could predict the results of a sputum smear in patients with active pulmonary tuberculosis. Methods: Forty-eight patients with active pulmonary tuberculosis were divided into 2 groups: sputum smear-positive (n = 25) and -negative (n = 23). The HRCT findings were retrospectively reviewed, focusing on the presence or absence of features previously reported to indicate active pulmonary tuberculosis, including ground-glass opacity, cavitation, centrilobular opacity, and air space consolidation. Results: Although air space consolidation was the least common feature overall, it occurred significantly more frequently in the smear-positive group than in the smear-negative group. This feature also had the highest specificity and positive predictive value. Cavitation and ground-glass opacity also occurred significantly more frequently in the smear-positive group. The frequency of centrilobular opacity did not differ between the 2 groups. Conclusions: The present study suggested that the HRCT findings of air space consolidation, cavitation, and ground-glass opacity are significantly associated with smear-positive pulmonary tuberculosis.

Radiation exposure to interventional radiologists during manual-injection digital subtraction angiography

Purpose: We investigated the relationship between the amount of radiation exposure to the operator during tableside manual-injection angiographic procedures including digital subtraction angiography (DSA) and the operator’s position, as well as a simple means to decrease radiation exposure.Methods: Measurement of radiation exposure was carried out with thermoluminescent dosimeters (TLDs) in nine abdominal angiographies. In the first study, radiation exposure during DSA or during fluoroscopy was measured using TLDs placed near the angiographic table. In the second study, radiation exposure to the interventional radiologist was measured during manual-injection DSA at a near and a far operator position.Results: Radiation exposure to the operator received during manual-injection DSA accounted for more than 90% of the total procedural exposure. The exposure to the operator markedly decreased at the far position compared with that at the near position when performing DSA.Conclusion: Manual-injection DSA is the largest contributor to radiation exposure received by the interventional radiologist, therefore, the use of a power injector is always recommended when performing DSA. When manual-injection DSA is necessary, radiologists should position themselves as far away from the patient as possible.

Endovascular Treatment for an Iliac Artery–Ureteral Fistula with a Covered Stent

Iliac artery-ureteral fistula (IAUF) is a rare entity that has a potential risk of life-threatening hemorrhage. It is difficult to diagnose and treat appropriately. Conventional treatment for the disease consists of surgical ligation and vascular reconstruction or coil embolization. Surgical treatment is usually difficult for patients with several risk factors. In recent years, endovascular stent-graft treatment for iliac artery pseudoaneurysm has been reported. The present report describes two cases in which endovascular covered stent-graft treatment was successfully applied to treat IAUF, with good clinical outcomes.

Rare Causes of Hematuria Associated with Various Vascular Diseases Involving the Upper Urinary Tract

Hematuria is a commonly encountered symptom of a wide spectrum of diseases, including calculi, tumors, and vascular abnormalities. In rare cases, hematuria is caused by life-threatening vascular diseases. When hematuria is encountered, physicians sometimes fail to include vascular diseases in the differential diagnosis because of their rare association with hematuria. Likewise, radiologists often fail to do so because of the low frequency of occurrence of these diseases. Multidetector computed tomography performed with the bolus injection technique should be the first-line diagnostic test when vascular disease is suspected. Radiologists should be familiar with the various imaging findings of hematuria caused by vascular disease. They should also be familiar with the management options (including endovascular techniques) for hematuria caused by vascular disease, since in some cases affected patients can be treated with interventional procedures.

Percutaneous long-term arterial access with implantable ports: Direct subclavian approach with US

PURPOSEnTo clarify the clinical feasibility of getting a long-term arterial access at the subclavian region by directly puncturing the artery under ultrasound guidance.nnnMATERIALS AND METHODSnPercutaneous placements of arterial infusion catheters with implantable ports were performed in 30 patients with malignant abdominal tumors. The axillary artery in the subclavian region was punctured directly with an 18G needle under ultrasound guidance. Using the Seldinger technique, a 5Fr catheter was placed with its tip in the hepatic or the other tumor-supplying arteries. The catheter was connected to an implantable port, and both of them were embedded in the subcutaneous pocket.nnnRESULTSnPercutaneous placements of infusion catheters were successfully performed in 29 cases. Transarterial chemotherapy through implanted ports was done uneventfully in 26 patients, while in the other three cases, catheter dislodgment occurred. Two local haematomas, one wound infection and one cerebellar infarction were also experienced.nnnCONCLUSIONnUltrasound-guided subclavian approach is a minimally invasive way of implanting an infusion catheter for chemotherapy, although its indication for severely atherosclerotic patients should be limited.

Nonlinear Geometric Warping of the Mask Image: A New Method for Reducing Misregistration Artifacts in Digital Subtraction Angiography

AbstractPurpose: Misregistration artifact is the major cause of image degradation in digital subtraction angiography (DSA). The purpose of this study was to evaluate the efficacy of a newly developed nonlinear geometric warping method to reduce misregistration artifact in DSA.n Methods: The processing of the images was carried out on a workstation with a fully automatic computerized program. After making differential images with a lapracian filter, 49 regions of interest (ROIs) were set in the image to be processed. Each ROI of the live image scanned the corresponding ROI of the mask image searching for the best position to match itself. Each pixel of the mask image was shifted individually following the data calculated from the shifts of the ROIs. Five radiologists compared the images produced by the conventional parallel shift technique and those processed with this new method in 16 series of cerebral DSA.n Results: In 14 of 16 series (88%), more radiologists judged the images processed with the new method to be better in quality. Small arteries near the skull base and veins of low density were clearly visualized in the images processed by the new method.n Conclusion: This newly proposed method could be a simple and practical way to automatically reduce misregistration artifacts in DSA.

Periportal high intensity on T2-weighted MR images in acute viral hepatitis.

The frequency and degree of periportal high intensity (PHI) on T2-weighted images in 28 patients (32 MR studies) with acute viral hepatitis were analyzed with regard to the various levels of serum glutamic-oxaloacetic transaminase (SGOT) and clinical phases. Periportal high intensity was found in 16 of 32 MR studies (50%) and no definite PHI was found in 7 studies (22%). Periportal high intensity appeared when the SGOT level was >500 IU or when the phase of the disease was early. Follow-up studies revealed that PHI decreased during clinical recovery. We conclude that the degree of PHI on T2-weighted images reflects the severity of the disease in acute viral hepatitis.

Feasibility of liver weight estimation by postmortem computed tomography images: An autopsy study

Although organ weight gives pathologists information about the pathogenesis of diseases at autopsy, the knowledge is rarely helpful in postmortem virtual autopsy by computed tomography (CT). To investigate the feasibility of liver weight estimation based on liver volume estimated from three‐dimensional CT images and the specific gravity of liver, thirty cadavers who died in the University of Fukui Hospital and whose family members agreed to postmortem CT and autopsy were prospectively enrolled. Mean specific gravity of liver was 1.054 ± 0.009u2009g/mL (95% confidence interval: 1.0507–1.0573u2009g/mL). The specific gravity was positively correlated to Hounsfield unit (HU) values of less than 40 (cases with moderate to severe fatty deposition) and remained stable between 1.05 to 1.065u2009g/mL for HU values greater than 40 (cases with mild or no fatty change). The liver weight estimated by our formula corresponded well to the actual liver weight, and the correlation coefficient was 0.96 (P < 1 × 10−13). The estimated liver weight calculated from estimated liver volume and the specific gravity of 1.055u2009g/mL was highly accurate, whereas the specific gravity should be reduced by 2%–3% in patients with an HU value less than 40 due to fatty deposition.

Persistent release of noradrenaline caused by anticancer drug 4′-epidoxorubicin in rat tail artery in vitro

Anthracycline derivatives including 4-epidoxorubicin are known to cause cardiovascular side effects. In this study we examined the effects of 4-epidoxorubicin on sympathetic nerves of rat tail artery in vitro. Treatment with 4-epidoxorubicin at concentrations higher than 10 microM gradually increased the resting tension of the arterial strips, an effect which was greatly enhanced by subsequent addition of 10 microM cocaine. This increase of the resting tension by 4-epidoxorubicin was prevented by prazosin, suppressed in the arterial strips of reserpine-pretreated rats, and reduced by superoxide dismutase. However, tetrodotoxin and histamine receptor antagonists (diphenhydramine and cimetidine) failed to influence it. The contractile response to electrical sympathetic stimulation was slightly attenuated by 30 microM 4-epidoxorubicin. 4-epidoxorubicin did not shift the concentration-response curve for noradrenaline. In the superfusion experiments, the basal release of noradrenaline was increased approximately five-fold by 30 microM 4-epidoxorubicin, and this increase was not inhibited by 0.1 microM prazosin, 0.5 microM tetrodotoxin, 10 microM cocaine or Ca2+-free medium. Noradrenaline release evoked by electrical stimulation was gradually suppressed by 30 microM 4-epidoxorubicin treatment. These results suggest that 4-epidoxorubicin directly acts on the sympathetic nerve to cause persistent release of noradrenaline in rat tail artery.

Postmortem CT is more accurate than clinical diagnosis for identifying the immediate cause of death in hospitalized patients: a prospective autopsy-based study.

Despite 75 to 90xa0% physician accuracy in determining the underlying cause of death, precision of determination of the immediate cause of death is approximately 40xa0%. In contrast, two thirds of immediate causes of death in hospitalized patients are correctly diagnosed by postmortem computed tomography (CT). Postmortem CT might provide an alternative approach to verifying the immediate cause of death. To evaluate the effectiveness of postmortem CT as an alternative method to determine the immediate cause of death in hospitalized patients, an autopsy-based prospective study was performed. Of 563 deaths from September 2011 to August 2013, 50 consecutive cadavers undergoing hospital autopsies with consent for additional postmortem CT at the University of Fukui were enrolled. The accuracy of determination of the immediate cause of death by postmortem CT was evaluated in these patients. Diagnostic discrepancy was also compared between radiologists and attending physicians. The immediate cause of death was correctly diagnosed in 37 of 50 subjects using postmortem CT (74xa0%), concerning 29 cases of respiratory failure, 4 of hemorrhage, 3 of liver failure and 1 of septic shock. Six cases of organ failure involving 13 patients were not identified as the cause of death by postmortem CT. Regarding the immediate cause of death, accuracy of clinical diagnosis was significantly lower than that of postmortem CT (46 vs 74xa0%, Pxa0<xa00.01). Postmortem CT may be more useful than clinical diagnosis for identifying the immediate cause of death in hospitalized patients not undergoing autopsy.