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Tatsuo Kumazaki

Publications and source records attributed to Tatsuo Kumazaki.

71 records · Page 4Linked to original sources
PubMed2002

T1-weighted magnetic resonance imaging sequence appropriate for the evaluation of the longitudinal relaxation effect of superparamagnetic iron oxide: a phantom study.

The goal of this study was to determine a T1-weighted magnetic resonance (MR) imaging sequence appropriate for evaluating the longitudinal relaxation effect of superparamagnetic iron oxide (ferumoxides) in a phantom study. An agarose phantom that included various concentrations of ferumoxides (0 - 0.5 mmol/l in 0.05 mmol/l increments) was examined for six types of T1-weighted imaging sequences using a 1.5-T MR unit. Three-dimensional (3D) fast spoiled gradient-echo (SPGR) imaging with a short echo time showed a strong linear correlation between the concentration of ferumoxides and the enhancement ratio. Two-dimensional (2D) fast SPGR imaging showed a high signal-to-noise ratio of the phantom even at low ferumoxides concentrations. These results suggest that 3D fast SPGR imaging is an appropriate technique for the evaluation of the longitudinal relaxation effect of ferumoxides, and that 2D fast SPGR imaging can be useful for evaluating the longitudinal relaxation effect at lower ferumoxides concentrations.

Dextrans↗
PubMed2002

[Assessment of biventricular function using gated blood pool SPECT with QBS software: comparison with planar radionuclide ventriculography].

UNLABELLED: Quantitative blood pool SPECT (QBS) is a new application for the quantitative assessment of biventricular function from gated blood pool SPECT (TMUGA). In this study, we compared biventricular function between planar radionuclide ventriculography and TMUGA. The reproducibility of measuring biventricular ejection fraction with QBS was also evaluated. MATERIALS AND METHODS: Thirty-five patients with cardiac disease were enrolled. Following intravenous bolus injection of 740 MBq of 99mTc human serum albumin-DTPA, first-pass radionuclide angiography (FP) and 25-gated interval planar multi-gated blood pool scintigraphy (PMUGA) were performed for the measurement of right ventricular ejection fraction (RVEF; %) and left ventricular ejection fraction (LVEF; %), respectively. Subsequently TMUGA data set was acquired with a dual-head gamma camera (16 gated intervals). Then, alternative LVEF and RVEF were measured using TMUGA with QBS. Regional left ventricular wall motion for both PMUGA and TMUGA were assessed with a 4-point scoring system respectively. RESULTS: Automatic biventricular border detection using QBS was feasible in 27 of 35 patients (70.7%). Measurements of TMUGA LVEF and RVEF were well reproducible, with interobserver correlation coefficient of 0.98 and 0.97, respectively. TMUGA LVEF showed excellent correlation with PMUGA LVEF (r = 0.98, SEE = 3.92%). The agreement of LV wall motion score between TMUGA and PMUGA was 88.1% (214 of 243 segments), with a kappa value of 0.82. On the other hand, RVEF determined by QBS had a 12.4% average overestimate compared to the same value obtained by FP. Moreover 95% confidential interval of TMUGA RVEF (-28.8 to +4.0%) was wider than that of TMUGA LVEF (-10.7 to +10.7%). CONCLUSION: TMUGA with QBS analysis provided accurate and reproducible data for global and regional left ventricular function. However, the results of RVEF with TMUGA were not satisfying as a replacement for those with FP and modifying the algorithm were needed to improve accuracy of quantification.

Adult↗
PubMed2002

[Cardiac pool scintigraphy using the solid-state Digirad 2020tc Imager--comparison with the conventional anger-type gamma camera using moving cardiac phantom].

UNLABELLED: Movable gamma camera, 2020tc Imager, was light miniaturized using Si photodiode as a semiconductor sensor instead of photomultiplier tubes. To validate performance of this new camera in cardiac pool scintigraphy, multigated equilibrium radionuclide ventriculography using the moving cardiac phantom was performed with 2020tc Imager and a conventional Agner-type gamma camera (PRISM 3000). METHOD: Both measured cardiac functional values were compared with the set-up ones for the phantom. Five-, 7.5-, and 10-minute-multigated data were acquired using both cameras under constant contractile condition. Constant 5-minute-multigated data acquisitions using 2020tc Imager were also carried out with varied contractile conditions. RESULTS: Measured ejection fraction (EF) derived from 2020tc Imager and an Anger-type camera were 68.5 +/- 0.6 and 70.3 +/- 1.4%, respectively. Both of these values were absolutely close to the set-up EF value of 70%. Both of end-diastolic volume and EF showed excellent correlation between set-up and measured values with the correlation coefficient of 0.97 and 0.99, respectively. CONCLUSION: This new movable camera could provide comparative cardiac functional values with an Anger-type camera and it can be useful to evaluate acute cardiac function in a coronary care unit.

Gamma Cameras↗
PubMed2001

Quantitative and qualitative assessment of reactive hematopoietic bone marrow in aplastic anemia using MR spectroscopy with variable echo times.

OBJECTIVE: To assess quantitative and qualitative differences in water components between normal bone marrow and reactive hematopoietic marrow in aplastic anemia using magnetic resonance (MR) spectroscopy with variable echo times (TEs). DESIGN: Water content, T2 value of the water component, and signal change in water related to TE were assessed in normal bone marrow and reactive hematopoietic bone marrow by a stimulated echo acquisition mode with TEs of 30, 45, 60, and 90 ms. PATIENTS: Six patients with aplastic anemia (13-84 years) and seven normal volunteers (25-38 years) were examined. RESULTS AND CONCLUSION: Reactive hematopoietic marrow showed significantly higher water content than normal bone marrow. The T2 value of water components tended to be longer in reactive hematopoietic marrow. Water signal ratio related to TE was significantly higher in reactive hematopoietic marrow. These results suggest a quantitative and qualitative difference in water components between normal and reactive hematopoietic bone marrow.

Adolescent↗
PubMedDate not supplied

Magnetic resonance imaging of gastrointestinal stromal tumor in the abdomen and pelvis.

This study aimed to evaluate magnetic resonance (MR) imaging appearances of 11 gastrointestinal stromal tumors in the abdomen and pelvis and compared them with some histological findings. Gastrointestinal stromal tumor showed nonhomogeneous signal intensity and included hemorrhage in large tumors. Gastrointestinal stromal tumors showed a wide variety of enhancement, and contrast enhancement of the tumor was consistent with mitosis index as well as the largest diameter of the tumor. Contrast-enhanced MR imaging may be useful in the assessment of tumor activity.

Abdominal Cavity↗
PubMedDate not supplied

Usefulness of gated myocardial perfusion SPECT imaging soon after exercise to identify postexercise stunning in patients with single-vessel coronary artery disease.

BACKGROUND: This study determines the value of gated single photon emission computed tomography (SPECT) imaging soon after exercise to identify patients with single-vessel disease and exercise-induced prolonged myocardial dysfunction (ie, postischemic stunning). METHODS AND RESULTS: We examined 19 normal individuals and 52 patients with single-vessel disease by use of 2-day technetium 99m tetrofosmin exercise/rest gated SPECT imaging. Sequential imaging was started 10, 30, and 50 minutes after exercise. The ejection fraction (EF) values were calculated with the Cedars-Sinai program. The participants were classified as follows: group A (normal individuals, n = 19), group B (individuals with coronary stenosis without Q-wave infarction, n = 18), group C (individuals with Q-wave infarction without myocardial ischemia, n = 15), and group D (individuals with Q-wave infarction and ischemia, n = 19). The post-stress EF values at 10 minutes (69.8% +/- 9.6% and 59.8% +/- 11.8%, respectively) were higher in groups A and C than those at 30 minutes (67.6% +/- 10.2% and 57.2% +/- 11.3%, respectively) ( P < .05) but were lower in group B (61.7% +/- 9.2%) than both the 30- and 50-minute values (64.2% +/- 9.5% and 64.6% +/- 9.4%, respectively; P < .05). The EF value did not significantly change in group D. CONCLUSIONS: Tc-99m gated SPECT imaging soon after exercise is superior to conventional late imaging to discriminate patients with single-vessel disease and postexercise stunning.

Adult↗
PubMedDate not supplied

Computed tomography and magnetic resonance imaging findings in cases of dermoid cyst coexisting with surface epithelial tumors in the same ovary.

OBJECTIVE: The purpose of this work was to describe the computed tomography (CT) and magnetic resonance imaging (MRI) findings in cases of dermoid cysts coexisting with surface epithelial tumors in the same ovary. METHODS: The pathologic reports of 141 dermoid cysts, 97 mucinous and 35 serous tumors were reviewed. The CT and/or MR images in the cases with a dermoid cyst and a surface epithelial tumor coexisting in the same ovary were analyzed. RESULTS: Eleven cases of mucinous tumors (6 benign, 3 low-grade, and 2 malignant) coexisted with dermoid cysts. Mucinous tumors were found in coexistence with 11.3% of dermoid cysts, and dermoid cysts were found in coexistence with 7.8% of mucinous tumors. In 10 cases, 3 radiologic patterns were observed: small fatty foci in the septa of the cystic tumor, an adjacent fat-containing component and a septated cystic component, and a dermoid cyst with no detectable mucinous tumor component. No histopathologically specific differences were observed between these groups. Small amounts of mucinous components were difficult to detect, but small fatty foci were easily detected. In 1 case, mucinous carcinoma formed a mass lesion in the wall of the dermoid cyst. CONCLUSIONS: The coexistence of these two neoplasms was not rare. If a dermoid cyst accompanies a multiseptated cyst and if the multiseptal cyst contains fatty foci, these two components may be associated. Recognizing the potential for the coexistence of these two neoplasms in the same ovary is essential for making a correct diagnosis.

Adolescent↗
PubMedDate not supplied

Bleeding portal-hypertensive gastropathy managed successfully by partial splenic embolization.

The use of partial splenic embolization to decrease portal pressure and reduce gastric bleeding from portal-hypertensive gastropathy, a complication of liver cirrhosis, is described. A 62-year-old man with hepatic cirrhosis secondary to hepatitis C and documented portal hypertension was admitted with hypersplenism and bleeding esophageal varices. Endoscopic ligation successfully controlled acute bleeding, but blood loss continued over the next 45 days. Bleeding secondary to portal-hypertensive gastropathy was diagnosed endoscopically. The patient's poor surgical status precluded a portosystemic shunt procedure, so partial splenic embolization was performed radiologically by the injection of Gelfoam squares. Splenic volume decreased 50% following partial embolization. Over 3 weeks, the hemoglobin concentration increased from 8.5 g/dL to 9.8 g/dL, and the platelet count increased from 41,000 to 90,000/microL. Repeat endoscopy found no gastric bleeding 18 days post-procedure. Partial splenic embolization is a radiologic procedure which can be performed safely in patients too ill to undergo portosystemic shunt. This report documents its successful use to manage hypersplenism and reduce portal pressure in a cirrhotic patient with portal-hypertensive gastropathy and hypersplenism.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Control of isolated gastric varices by combination therapy using embolization and endoscopic scleroligation therapy.

Balloon-occluded retrograde venous obliteration is a powerful new technique for eliminating gastric varices. However anatomic considerations may preclude its use in some instances. Two cases are reported in which combination embolization followed by endoscopic injection scleroligation therapy eradicated isolated gastric varices where balloon-occluded retrograde venous obliteration was impossible. Two men with alcoholic cirrhosis were admitted with bleeding gastric varices. Inability to access variceal venous drainage precluded balloon-occluded retrograde venous obliteration. In Case 1, transileocolic vein obliteration left gastric embolization, and partial splenic embolization only partially eradicated gastric varices. In Case 2, percutaneous transhepatic obliteration, left gastric embolization, and partial splenic embolization were only partially successful. In both cases, endoscopic injection scleroligation therapy was performed adjunctively. Endoscopic injection scleroligation therapy completely eradicated gastric varices in both patients following partially successful embolization therapy. These cases demonstrate the importance of individualizing treatment of esophageal varices, the value of combination therapy, and the effectiveness of endoscopic injection scleroligation therapy for treating varices.

Aged↗
PubMedDate not supplied

Long-term hematological and biochemical effects of partial splenic embolization in hepatic cirrhosis.

BACKGROUND/AIMS: Partial splenic embolization was developed as a non-surgical treatment for hypersplenism, but recently splenic embolization has been reported to improve the hepatic function. We undertook long-term evaluation of partial splenic embolization in patients with hepatic cirrhosis in comparison with patients not undergoing embolization. METHODOLOGY: We performed embolization in 26 patients with cirrhosis. The controls consisted of 26 with cirrhosis patients who were not undergone embolization. RESULTS: Red blood cell counts of embolized patients had increased significantly at 6 months after the procedure, remaining increased for up to 7.5 years. Platelet counts increased maximally by 2 weeks after embolization, followed by a gradual decrease. Nonetheless, platelets remained significantly more numerous than before embolization for up to 8 years. Neither aspartate aminotransferase nor alanine aminotransferase activities in serum changed significantly during follow-up. Choline esterase activity increased significantly by 6 months after embolization and remained increased for more than 7 years. Serum albumin concentration increased significantly, beginning at 6 months after embolization; this increase was maintained for 6 years. Survival did not differ between embolized and non-embolized groups. CONCLUSIONS: Partial splenic embolization is a beneficial non-surgical treatment that enhances hepatic protein synthetic capacity as well as alleviating hypersplenism in patients with cirrhosis.

Alanine Transaminase↗
PubMedDate not supplied

Renal artery stenosis in a patient with Leriche syndrome: brachial artery access for stent placement.

We encountered a patient with Leriche syndrome and general atherosclerotic disease. His renal function had deteriorated, and diabetic nephropathy was suspected. Severe left renal artery stenosis was also found and considered, if untreated, to be an important factor in aggravation of his renal function. Because the infrarenal abdominal aorta was completely occluded, we treated the patient by insertion of a stent into the left renal artery from the brachial approach. The operation was successful, without residual stenosis or complications. Renal blood flow was remarkably improved after stent placement.

Aorta, Abdominal↗
PubMedDate not supplied

Manual aspiration thrombectomy with a standard PTCA guiding catheter for treatment of acute massive pulmonary thromboembolism.

PURPOSE: To evaluate the efficacy and safety of percutaneous manual aspiration thrombectomy for the treatment of acute massive pulmonary thromboembolism with hemodynamic impairment. MATERIALS AND METHODS: Over a period of 6 years and 9 months, 15 patients with hemodynamic impairment (4 men, 11 women; aged 27-79 years) were treated by manual clot aspiration with a standard, large-lumen percutaneous transluminal coronary angioplasty (PTCA) guiding catheter. RESULTS: After treatment, angiography demonstrated improvement of pulmonary perfusion in all patients (mean Miller score: before treatment 18.9, after treatment 12.1; P < 0.01). Mean pulmonary arterial pressure decreased from 29.6 to 22.5 mmHg (P < 0.01). The mean treatment time was 114.2 min. All of the patients survived and their clinical status improved. No patient had any significant complication. CONCLUSION: Percutaneous manual aspiration thrombectomy with a standard 8 Fr PTCA guiding catheter achieved rapid, safe improvement of the hemodynamic situation in cases of acute massive pulmonary thromboembolism, with low cost both in terms of time and money.

Adult↗
PubMedDate not supplied

Transcatheter management for multiple liver tumors after hepatic artery obstruction following reservoir placement.

BACKGROUND/AIMS: Hepatic arterial infusion chemotherapy via an implantable port system has been widely used to treat unresectable liver neoplasms. Complications of the hepatic artery occlusion following reservoir placement, however, makes it impossible to continue the infusion therapy. The purpose of our study was to assess the possibility of transcatheter treatment after the hepatic artery obstruction following reservoir placement. METHODOLOGY: Between April 1999 and May 2002, 14 patients with liver tumors had the complication of hepatic artery obstruction following reservoir placement. We conducted a prospective trial to assess 1) the collateral pathways of feeding artery using angiography, 2) the possibility of transcatheter treatment or 3) re-reservoir placement for liver tumors. RESULTS: 1) Angiography revealed that the main collateral pathway of the feeding artery was the inferior phrenic artery in 7 patients (50%), the dorsal pancreatic artery in 4 patients (29%) and the anastomotic branch of the celiac axis in 1 patient (7%). The main collateral pathway could not be detected in 2 patients (14%). 2) Transcatheter treatment was successfully performed in all patients (100%). 3) Rereservoir placement failed in all cases. CONCLUSIONS: These results suggest that transcatheter treatment may be possible for patients with hepatic artery obstruction.

Adult↗
PubMedDate not supplied

Changes in distribution of splenic venous flow in the patients with cirrhotic liver.

BACKGROUND/AIMS: The aim of this study is to prove the hemodynamic change in distribution of splenic venous flow in the liver, especially in the cirrhotic liver, and to reveal and evaluate a participation of splenic venous flow in regeneration or enlargement of the hepatic lobe. METHODOLOGY: We studied the distribution of splenic venous flow in the liver of patients with normal liver (NL group, n=15), chronic hepatitis (CH group, n=8), and liver cirrhosis (LC group, n=13) with the technique of scintiphotosplenoportography after percutaneous intrasplenic injection of Technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin. The index of splenic venous flow volume per unit hepatocytes (Vunit) was calculated in each hepatic lobe. To compare V value of the left lobe (VLunit) with that of the right lobe (VRunit), predominant index of the left lobe (L/R index) was defined as L/R index = VLunit/VRunit. RESULTS: The median (interquartile range) of L/R index of the LC group; 1.22 (1.06-1.70) was significantly higher than that of the NL group; 0.83 (0.66-0.92), p<0.001 and the CH group; 0.79 (0.69-0.92), p<0.001. CONCLUSIONS: L/R index reflects the change of portal hemodynamics in cirrhotic liver and is useful for discrimination between noncirrhosis and cirrhosis. These results suggest that in the liver exposed to continuous damages, splenic venous blood promotes liver fibrosis in the right lobe and eventually flows more into the left lobe with milder fibrosis.

Aged↗