Biomedical subjects

Shigeru Sase

Publications and source records attributed to Shigeru Sase.

4 recordsLinked to original sources

PubMed2003

Noninvasive quantitative measurement of tissue blood flow in hepatocellular carcinoma using xenon-enhanced computed tomography.

The aim of this study was to quantitatively measure tissue blood flow (TBF) in hepatocellular carcinoma (HCC) by a noninvasive method using xenon (Xe) inhalation/CT scans and to correlate the measured TBF with histological features. TBF was measured in HCC with xenon-enhanced CT (xenon/CT) in 20 patients. In 15 patients with HCC diagnosed as hypervascular tumors by conventional CT, TBF of the tumors was significantly higher than that of noncancerous liver tissue (151.1 +/- 20 vs 42.6 +/- 20 ml/min/100 g). Histologically, these tumors were diagnosed as moderately-to-poorly differentiated HCC. In contrast, in five patients with hypovascular HCC, TBF of HCC was almost comparable to that of the noncancerous regions (45.3 +/- 6 vs 48.3 +/- 6 ml/min/100 g). All these tumors were well-differentiated HCC. In conclusions, the measured values of TBF correlate with the clinicopathologic features of liver tumors and nontumorous liver tissue in patients with HCC.

Administration, Inhalation↗

PubMedDate not supplied

Hepatic blood flow measurements with arterial and portal blood flow mapping in the human liver by means of xenon CT.

PURPOSE: The purpose of this work was to quantify arterial and portal blood flows in the human liver and to create blood flow maps by means of xenon CT. METHOD: Mathematical procedures were developed based on a simplified model having two tissue components: liver tissue and portal organ tissue. Xe-CT studies were performed on 10 healthy volunteers (ages 33.4 +/- 9.8 years), a patient with hepatocellular carcinoma (HCC), and a liver transplant recipient. RESULTS: Arterial and portal blood flows for the healthy subjects were 36.7 +/- 5.2 and 65.2 +/- 22.0 ml/100 ml/min. In the HCC patient, arterial blood flow was shown to be dominant in the tumoral area. From the results of the liver recipient, it was demonstrated that obtaining lambda values is important for proper evaluation of blood flows. CONCLUSION: Xe-CT can provide substantial information on hepatic blood flow quantitatively and visually with separation of arterial and portal components.

Adult↗

PubMedDate not supplied

Quantitative cerebral blood flow calculation method using white matter lambda in xenon CT.

The objective of this work is to propose a quantitative cerebral blood flow (CBF) calculation method for xenon CT (Xe-CT) by logically estimating the time course change rate (rate constant) of the arterial xenon concentration from that of end-tidal xenon concentration. A single factor, gamma (gamma), which is considered to reflect the diffusing capacity of the lung for xenon, was introduced to correlate the end-tidal rate constant (Kend-tidal) with the arterial rate constant (Karterial). When an appropriate value is given to gamma, it is possible to calculate the arterial rate constant (calculated Karterial) from Kend-tidal. A procedure was developed to determine the gamma value utilizing the characteristics of white matter lambda (lambda). This procedure was applied to three healthy volunteers. The gamma gammaalues for the three subjects were consistent with those directly calculated from end-tidal and arterial (abdominal aorta) xenon data. Hemispheric CBF values with use of calculated Karterial (47.3 +/- 10.3 ml/100 g/min) were close to the reported normative values. We conclude this method could make current Xe-CT examinations substantially reliable and quantitative in measuring CBF.

Adult↗

PubMedDate not supplied

Quantitative multilevel mapping of hepatic blood flow by xenon computed tomography using aorta.

A noninvasive and quantitative technique has been developed to measure human hepatic blood flow by xenon computed tomography (Xe-CT). Accurate data on time-dependent xenon concentrations in the arterial blood are indispensable for Xe-CT to ensure quantitativeness of measured blood flow. A method has been established by our group to use both aorta and end-tidal data to obtain arterial xenon information. Multilevel (3 levels) maps of arterial blood flow (Fa), portal blood flow (Fp), and partition coefficient (lambda) were created for patients with chronic hepatitis. A method to objectively evaluate Fa, Fp, and lambda values for the whole liver has also been developed by our group.

Aorta↗