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C Kuroda

Publications and source records attributed to C Kuroda.

172 records · Page 10Linked to original sources
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MR features of various histological grades of small hepatocellular carcinoma.

Twenty small hepatocellular carcinomas (HCCs) < 20 mm in diameter in 18 patients, detected by MRI, were surgically resected and histologically confirmed. Quantitative analysis of signal intensity on MR images was performed with 14 homogeneous lesions. In the five grade I HCCs, T1-weighted SE sequences provided significantly higher mean tumor-liver contrast and contrast-to-noise ratio (C/N) than T2-weighted SE sequences (p < 0.01). However, in the other nine HCCs (grade I + II or greater), T2-weighted SE sequences had significantly higher mean tumor-liver contrast and C/N values than T1-weighted SE sequences (p < 0.001). The T2-weighted SE sequences appear superior to T1-weighted SE sequences for grade I + II or greater HCC detection, whereas T1-weighted SE sequences are valuable in the detection of grade I HCCs.

Aged↗
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Double phase CT arteriography of the whole liver in the evaluation of hepatic tumors.

PURPOSE: Our goal was to evaluate the contribution of double phase CT arteriography (CTA) of the whole liver to differentiate hepatic tumors from false-positive areas on CT during arterial portography (CTAP). METHODS: In 38 candidates for surgical resection of hepatic tumors, both CTAP and double phase CTA were performed. A total of 68 perfusion defects were identified at CTAP. Of 68 perfusion defects, 47 were found to represent hepatic tumors [hepatocellular carcinoma (HCC), n = 31; hepatic metastasis, n = 13; cholangiocarcinoma n = 2; focal nodular hyperplasia, n = 1]. The other 21 perfusion defects were defined as perfusion abnormalities in which focal hepatic masses had not been identified at surgery or pathologic analysis. The phase one CTA scanning started 12 s after the beginning of the injection of contrast material, and the phase two CTA scanning started 20 s after the end of the phase one CTA, with 60 ml of contrast agent (150 mg I/ml) injected at a rate of 2 ml/s. RESULTS: On phase one CTA, only 1 lesion in 31 HCCs showed rim enhancement and 26 HCCs (84%) had rim enhancement on phase two CTA. Twelve lesions (80%) of the hepatic metastases and cholangiocarcinomas had rim enhancement on phase one CTA and 11 lesions (73%) showed rim enhancement on phase two CTA. Twenty-one perfusion abnormalities on CTAP did not show rim enhancement on either phase one or phase two CTA. CONCLUSION: Double phase CT arteriography of the whole liver was useful to differentiate hepatic tumors from perfusion abnormalities on CTAP.

Adult↗
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Computerized radiographic assessment of pulmonary blood flow in patients with and those without mitral stenosis.

The authors investigated whether a computerized analysis system can be used with chest radiography for estimating the redistribution of pulmonary blood flow in patients with and those without mitral stenosis (MS). Their system uses four-directional Laplacian-Gaussian filtering and binarization. As a physical measure, the radiographic index, which reflects the area of opacity in selected regions of interest (ROIs), was used. Fifteen men with MS and 15 men without MS were included in the study. ROIs were selected in the right upper and lower lung zones on radiographs, and the images were processed with the system. The radiographic indexes were determined in each ROI. As a measure of pulmonary blood flow redistribution, the upper-to-lower lung zone radiographic index ratio (U/L) was calculated. The U/L values correlated with pulmonary capillary wedge pressure values (r = .405, P = .025). The mean U/L value of the MS group was significantly higher than that of the non-MS group (1.16 +/- 0.14 vs 1.05 +/- 0.09, respectively; P = .016). These preliminary results indicate that this system can be used for quantitative estimation of the redistribution of pulmonary blood flow.

Aged↗
PubMedDate not supplied

Minute carcinoma of the pancreas measuring 1 cm or less in diameter--collective review of Japanese case reports.

BACKGROUND/AIMS: According to Tsuchiya's collective review on small pancreatic cancer measuring 2 cm or less in diameter (5), more than half of them had obstructive jaundice and the 5-year survival rate was as low as 30%. Thus, a more aggressive diagnostic approach is needed to detect a smaller and more curable cancer of the pancreas. METHODOLOGY: Thus, we collected 36 reported cases of "minute" pancreatic cancer measuring 1 cm or less in diameter, from Japanese medical literature, to analyze the relationships between the diagnostic processes and long-term results. RESULTS: Excluding 3 patients with obstructive jaundice, the other 33 patients did not show any specific initial symptoms. However, 28 (78%) out of 36 patients showed an elevation in serum pancreatic enzyme levels and/or glucose intolerance. Among the 35 patients who had received ultrasonography (US) and/or computed tomography (CT), 20 (57%) patients showed duct dilation alone, whereas only 9 patients (26%) showed tumor mass. Among 35 patients who received an endoscopic retrograde pancreatography (ERP), all patients showed positive findings such as obstruction/stenosis, filling defect or duct dilation. All 36 patients underwent pancreatectomy and the 5-year survival rate was 57%. However, the 5-year survival rate was 34% in the 13 patients with jaundice and/or tumor mass depicted in US/CT, while it was 69% for the 22 patients without these two findings (p < 0.05). CONCLUSIONS: These data lead us to conclude that an elevation of serum pancreatic enzyme levels, glucose intolerance, and duct dilation alone depicted by US/CT should not be overlooked. ERP should be more widely applied to such patients, instead of persisting in delineating the tumor mass by US/CT or follow-up by tumor marker.

Aged↗
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Reducing motion artifacts during hepatic DSA.

In hepatic digital subtraction angiography, artifacts caused by diaphragmatic motion can interfere with the correct diagnosis of hepatic lesions. This article describes the feasibility of using the exhalation holding method in reducing diaphragmatic motion artifacts in hepatic DSA. The authors compared respiratory holding methods in 30 patients who underwent hepatic DSA. They performed a blind comparison of images to assess diaphragmatic motion artifacts. Results showed the images obtained by the exhalation holding method were superior to those obtained by the inhalation holding method in 20 out of 30 series (66.7%).

Adult↗
PubMedDate not supplied

Using compensating filters to reduce radiation dose.

The study described in this article explores the role of compensating filters in reducing radiation exposure. Radiation exposure levels with and without filters were compared in skull radiographs, hepatic angiographs and one-shot full-length lower extremity radiographs. Absorbed doses were measured with and without a skull filter in a phantom at a depth of 5 cm. Results showed that filters reduced exposure by 29% in skull radiographs, 47% in hepatic angiographs and 80% in one-shot full-length lower extremity radiographs. Absorbed doses were reduced by more than 26% in the skull phantom in the filtered area. To reduce patient dose, the filters were positioned between the x-ray tube and the patient.

Absorption↗
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Types of diaphragmatic motion during hepatic angiography.

To determine the types and causes of diaphragmatic motion during hepatic angiography, the authors used transarterial cut-film portography (TAP) to study movement of the diaphragm during breath-holding. Thirty-three TAP sequences were studied, and the patients' diaphragmatic motions were classified into four categories according to the distance their diaphragms moved. Results showed that the diaphragm was stationary in 33% of the TAP studies, while perpetual motion occurred in 15% of the studies, early-phase motion occurred in 12% and late-phase motion occurred in 40%. Ten sequences showed diaphragmatic motion of more than 10 mm, with eight sequences showing caudal motion and two showing cranial motion. This article discusses the cause of diaphragmatic motion during breath-holding for hepatic angiography and presents suggestions to reduce motion artifacts during the exam.

Adult↗
PubMedDate not supplied

Reducing misregistration of mask image in hepatic DSA.

When performing hepatic digital subtraction angiography, misregistration of the mask image can cause artifacts that obscure pathology. For this article, researchers analyzed the breath expiration times of 59 patients and found that expiration times ranged from 1.8 seconds to 6 seconds. Thirty DSA series were obtained taking into account the patient's breath expiration time, and 35 series were obtained without taking the expiration time into consideration. Artifacts were detected in 20% of the DSA series where expiration time was taken into consideration and in 42.9% of series where it was not (p < 0.05). The research showed that misregistration of the mask image during hepatic DSA can be reduced by starting the exposure at the end of breath expiration.

Adult↗
PubMedDate not supplied

Oxygen administration during hepatic DSA.

The research presented in this article examined the role of oxygen in preventing diaphragmatic motion artifacts in delayed-phase hepatic digital subtraction angiography (DSA). The results demonstrate that administering oxygen to patients before the examination substantially reduces artifacts due to motion.

Adult↗