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Kuni Ohtomo

Publications and source records attributed to Kuni Ohtomo.

At least 37 records · Page 2Linked to original sources
PubMed2006

Proposal of blood volume-corrected model for quantification of regional cerebral blood flow with H2 15O-PET and its application to AVF.

PURPOSE: It is generally assumed that vascular tracer activity is negligible in the quantification of regional cerebral blood flow (rCBF) with H2 15O and positron emission tomography (PET) under normal conditions. We attempted to surpass the assumption of abnormal vascular conditions where the vascular tracer activity is significant by introducing the vascular component into the model. MATERIALS AND METHODS: H2 15O-dynamic and C15O PET scans were performed in an arteriovenous fistula (AVF) patient. Time-activity curves of regions of interest (ROIs) were analyzed with nonlinear least-square approximation to estimate the rCBF and fractional arterial blood volume (v(a)) simultaneously with the proposed model and the standard model. RESULTS: The proposed model curve showed a fit to the time-activity curve of H2 15O at an ROI containing an enlarged vascular space induced by the AVF. The relation between the estimated v(a) and CBV obtained with C15O-PET revealed that the ratio of v(a) to CBV was approximately 0.23. The estimated rCBF with the proposed model in nonlesion ROIs corresponded to those of the standard model, with the estimated V(d) 0.94 ml/ml. CONCLUSION: The results supported the hypothesis that the blood volume-corrected model is applicable to the quantification of rCBF in a region with abnormal vascular structure. Furthermore, one of the advantages of the model is the feasibility of simultaneous estimation of the rCBF and arterial blood volume with dynamic-H2 15O PET scans.

Blood Volume↗
PubMed2006

Assessment of major aortopulmonary collateral arteries with multidetector-row computed tomography.

Multidetector-row computed tomography (MDCT) studies were performed in three adult patients with pulmonary atresia with a ventricular septal defect. In all patients, the native pulmonary arteries were absent, and the pulmonary circulation was totally supplied by major aortopulmonary collateral arteries (MAPCAs). MDCT studies with 1-mm collimation provided detailed information on MAPCAs and bronchial collaterals, such as the numbers and sites of origin, their varying diameters, their courses, and the areas of the lungs they supply. MDCT studies may provide an efficient road map for safe and successful selective catheterization and may substitute for conventional angiography in patients with considerable risks.

Abnormalities, Multiple↗
PubMed2006

Magnetic resonance findings of bile duct adenoma with calcification.

Computed tomographic (CT) and magnetic resonance (MR) appearances of bile duct adenoma (BDA in a patient who underwent partial hepatectomy of segment 8 are presented. BDA showed a ring-shaped hyperdense area suggesting calcification and ring enhancement on CT. It appeared hypointense on both T1- and T2-weighted MR images. Preoperatively, the diagnoses considered included metastatic carcinoma, cholangiocarcinoma, tuberculosis, and rare tumors such as epithelioid hemangioendothelioma. The radiological findings were confirmed by pathological investigation.

Adenoma, Bile Duct↗
PubMed2006

Bezier surface reformation: an original visualization technique of cervical nerve roots on myelographic CT.

PURPOSE: The aim of this study was to assess the feasibility of an original reformation method of cervical myelographic computed tomography (CT) using the Bezier surface technique. MATERIAL AND METHODS: Presurgical myelographic computed tomography (CT) scans using a multidetector row CT scanner were performed in 25 patients with avulsion injury of the cervical nerve roots. Each volumetric data set was reformatted using Bezier surface technique to depict the individual nerve root in a single image. In the reformatted images, visualization of the dorsal and ventral nerve roots between C4 and T1 on the uninjured side (300 nerves) was rated. RESULTS: Bezier surface reformation (BSR) images depicted the dorsal and the ventral nerve roots between C4 and C8 in 125 (100%) and 125 (100%) of 125 nerves, respectively. The dorsal and the ventral nerve roots of T1 were depicted in 25 (100%) and 22 (88%) in 25 nerves, respectively. CONCLUSION: The BSR technique of cervical myelographic CT enables simultaneous display of multiple cervical nerve roots in one image. BSR is a feasible technique for the assessment of the cervical nerve roots.

Accidents, Traffic↗
PubMed2006

External beam radiotherapy to treat intra- and extra-hepatic dissemination of hepatocellular carcinoma after radiofrequency thermal ablation.

BACKGROUND: Radiofrequency ablation (RFA) is an alternative to percutaneous ethanol injection therapy (PEIT) for single non-surgical hepatocellular carcinoma. However, the risk of seeding along the needle track has been reported. METHODS: Seven patients presenting with neoplastic seeding after RFA or PEIT were treated with external beam radiotherapy using conventional fractionation. All patients underwent irradiation with a total dose in the range of 44-61 Gy (median and mode value: 50 Gy). RESULTS: An objective response to treatment was achieved in six of seven patients (86%). A complete response was obtained in two patients (29%). The median survival time was 14.7 months and the actuarial 1- and 2-year survivals were 67% and 50%, respectively. CONCLUSIONS: The response to treatment was relatively good without serious complications. Seeding from hepatocellular carcinoma is sensitive to external beam radiotherapy. It is useful in the treatment of these patients with 50 Gy in 25 fractions.

Aged↗
PubMed2006

Small bowel perforation without tumor recurrence after radiotherapy for cervical carcinoma: report of seven cases.

AIM: We describe the clinical presentation, evaluation, management and outcome of patients experiencing small bowel perforation following radiation therapy for cervical cancer. METHODS AND MATERIALS: A database consisting of 95 Japanese women with stage 0-4 A cervix cancer treated between 1991 and 2004 contained seven patients (7.4%) with small bowel perforation. RESULTS: The median age at the time of perforation was 72.5 years (range 62-78). The median time from completion of radiotherapy to perforation was 6 months (range 2-58). Surgery (one small bowel resection and anastomosis with diversion; six small bowel resection and anastomosis) was performed immediately in all seven patients. One of seven patients died of small bowel perforation (i.e. mortality rate was 14%). Bowel adhesion was detected during the operation in only three cases (43%). Signs of peritonitis were absent in six cases (86%). Severe abdominal pain was seen in all seven patients. The perforation site was ileum in all seven cases. In all patients, pathological changes were compatible with postirradiation injury of the gastrointestinal tract. CONCLUSIONS: The presenting complaints of patients with bowel perforation following radiotherapy vary, and signs of peritonitis may be absent. Emergency physicians must be alert for these complications in patients who have been treated with radiotherapy.

Aged↗
PubMed2006

Brachial plexus injury: clinical manifestations, conventional imaging findings, and the latest imaging techniques.

Brachial plexus injury (BPI) is a severe neurologic injury that causes functional impairment of the affected upper limb. Imaging studies play an essential role in differentiating between preganglionic and postganglionic injuries, a distinction that is crucial for optimal treatment planning. Findings at standard myelography, computed tomographic (CT) myelography, and conventional magnetic resonance (MR) imaging help determine the location and severity of injuries. MR imaging sometimes demonstrates signal intensity changes in the spinal cord, and enhancement of nerve roots and paraspinal muscles at MR imaging indicates the presence of root avulsion injuries. New techniques including MR myelography, diffusion-weighted neurography, and Bezier surface reformation can also be useful in the evaluation and management of BPI. MR myelography with state-of-the-art technology yields remarkably high-quality images, although it cannot replace CT myelography entirely. Diffusion-weighted neurography is a cutting-edge technique for visualizing postganglionic nerve roots. Bezier surface reformation allows the depiction of entire intradural nerve roots on a single image. CT myelography appears to be the preferred initial imaging modality, with standard myelography and contrast material-enhanced MR imaging being recommended as additional studies. Work-up will vary depending on the equipment used, the management policy of peripheral nerve surgeons, and, most important, the individual patient.

Brachial Plexus↗
PubMed2006

Focalized contractile impairment at hypertrophied myocardium proven in consideration of wall stress in patients with hypertrophic cardiomyopathy.

In hypertrophic cardiomyopathy (HCM) a hyperkinetic state is sometimes observed in spite of impaired systolic function in the hypertrophied myocardium. The aim of the present study was to determine the mechanism of this paradox. Seventeen patients with HCM and 10 normal subjects underwent cine magnetic resonance (MR) imaging to measure percent systolic wall thickening and percent fractional shortening. The ratio of systolic radial wall stress of the LV at the hypertrophied myocardium over that at the nonhypertrophied myocardium was evaluated to describe the focal advantageous condition for wall thickening. The ratio was 0.66 +/- 0.36 at the start of contraction and 0.78 +/- 0.31 at early-systole, indicating consistently smaller radial wall stress at the hypertrophied myocardium. Although the condition for contraction was favorable (a ratio less than 1.00), percent systolic wall thickening at the hypertrophied myocardium (23.0 +/- 11.8%) was smaller than that at the nonhypertrophied myocardium (70.5 +/- 32.3%). Smaller end-diastolic dimension (HCM group; 45.2 +/- 4.2 mm, reference group; 48.9 +/- 4.1 mm, P = 0.04) with a statistically identical value of systolic decrease in intraventricular dimension (HCM group; 19.7 +/- 3.9 mm, reference group; 18.9 +/- 3.2 mm, P = 0.60) yielded high percent fractional shortening in patients with HCM (43.5 +/- 7.6%). Although contractile impairment was proven at the hypertrophied region with low radial wall stress in the HCM group, the smaller end-diastolic dimension in this group resulted in high percent fractional shortening.

Cardiomyopathy, Hypertrophic↗
PubMed2005

Radiation therapy for portal venous invasion by hepatocellular carcinoma.

AIM: To clarify the efficacy and safety of three-dimensional conformal radiotherapy (3-D CRT) for this disease and to specify patient subgroups suitable for this treatment. METHODS: Fifty-two patients with HCC received PVI-targeted radiation therapy from January 1995 through December 2003. Portal venous invasion (PVI) was found in the second or lower order branches of the portal vein in 6 patients, in the first branch in 24 patients and in the main trunk in 22 patients. Child classifications of liver function before radiation therapy were A, B, and C for 19, 24 and 2 patients, respectively. All patients received three-dimensional conformal radiotherapy with a total dose ranging from 39 to 60 Gy (57.0 Gy in average). RESULTS: Overall survival rates at 1, 2, 3, 4, and 5 years were 45.1%, 25.3%, 15.2%, 10.1%, and 5.1%, respectively. Univariate analysis revealed that Child status, the number of tumor foci, tumor type, transcatheter arterial embolization (TAE) after radiation therapy were statistically significant prognostic factors. Multivariate analysis showed that the number of tumor foci and TAE after radiation therapy were statistically significant. CONCLUSION: The results of this study strongly suggest the efficacy of 3-D CRT as treatment for PVI in HCC. 3-D CRT is recommended in combination with post-radiation TAE for PVI of HCC with 5 tumor foci or less in the liver and with Child A liver function.

Adult↗
PubMed2005

Graft-versus-tumor effect against advanced pancreatic cancer after allogeneic reduced-intensity stem cell transplantation.

BACKGROUND: The prognosis of advanced pancreatic cancer is extremely poor and therefore a novel treatment strategy is desired. The authors thus started a prospective study of allogeneic reduced-intensity hematopoietic stem cell transplantation (RIST) for patients with advanced pancreatic cancer to evaluate the feasibility and efficacy of this approach for such patients. METHODS: Only patients with pathologically proven pancreatic cancer that was locally advanced or metastatic and not amenable to curative resection were included. The conditioning regimen consisted of gemcitabine, fludarabine, and busulfan. RESULTS: In the first stage of this study, the authors treated seven patients. Treatment-related mortality before day 100 was observed in one patient. The median survival after RIST was 229 days. An objective response on computed tomographic scan was observed in two patients and another had a tumor marker response. Marked tumor shrinkage was observed in one of the remaining patients after donor lymphocyte infusion. These antitumor effects appeared after the effect of the conditioning regimen had disappeared. In addition, some of these responses were associated with an increase in the serum anticarcinoembryonic antigen antibody level. CONCLUSIONS: Pancreatic cancer appeared to be sensitive to a graft-versus-tumor effect; therefore, a larger clinical study with a refined strategy is warranted.

Adult↗
PubMed2005

Detection of cerebrospinal fluid leakage in intracranial hypotension with radionuclide cisternography and blood activity monitoring.

UNLABELLED: Radionuclide cisternography is an indispensable examination to detect cerebrospinal fluid (CSF) leakage in patients suspected of having spontaneous intracranial hypotension (SIH). However, it sometimes fails to demonstrate the site of CSF leakage, and in such cases, early bladder visualization is utilized for the diagnosis of SIH as an indirect finding. The aim of this work is to improve the diagnostic ability of radionuclide cisternography and to reevaluate the reliability of early bladder visualization as an indirect finding of CSF leakage. METHODS: We obtained serial images during the first hour after injection as well as the following time points in 4 patients with SIH and 5 with normal pressure hydrocephalus (NPH) as a control. We also performed blood sampling over time to measure blood radioactivity concentrations. RESULTS: All 4 patients with SIH demonstrated leakage, 2 of 4 within one hour after injection. Bladder visualization was observed falsely in 4 of 5 patients with NPH, considered to be the result of a lumbar puncture complication. In this false bladder visualization, blood radioactivity showed a more rapid raise and fall than in CSF leakage of SIH. CONCLUSIONS: The combination of radionuclide cisternography, including early time points and blood sampling, may enable accurate diagnosis of SIH.

Adult↗
PubMed2005

Renal dysfunction after total-body irradiation. Significance of selective renal shielding blocks.

PURPOSE: A retrospective analysis was conducted on the outcome of total-body irradiation (TBI) followed by bone marrow transplantation (BMT) on leukemia patients. Also studied was the risk of renal dysfunction after TBI/BMT with or without the use of selective renal shielding blocks. PATIENTS AND METHODS: The cases of 109 leukemia patients who received TBI as a component of the conditioning regimen for their BMT were reviewed. They received 12 Gy of TBI in six fractions over 3 consecutive days. Doses to eyes and lungs were reduced to 7 Gy and 8 Gy, respectively, by customized organ shielding blocks. After March 1999, renal shielding blocks were used to constrain the renal dose to 10 Gy. The patients were followed for a median period of 16.6 months (range: 0.3-180.1 months). RESULTS: The 2-year and 5-year overall survival rates were 55.4% and 43.2%, respectively. Renal dysfunction-free rates were different between those with and without renal shielding blocks: 100% and 78.5%, respectively, at 2 years. Overall survivals were not significantly different among these patients: 60.4% and 52.9%, respectively, at 2 years in patients with and without renal shielding blocks (p = 0.53). CONCLUSION: The use of selective renal shielding blocks provided evidence for reducing radiation-induced renal toxicities without decreasing the overall survival rate.

Adolescent↗
PubMed2005

Crohn's disease with life-threatening hemorrhage from terminal ileum: successful control by superselective arterial embolization.

A case of life-threatening lower gastrointestinal hemorrhage from Crohn's disease is reported. Several promising studies have recently been published that describe superselective embolization for the treatment of massive lower gastrointestinal hemorrhage in patients with bleeding colonic diverticular disease and angiodysplasia, and success rates of 74%-93% have been reported. But in patients with Crohn's disease, successful superselective embolization has rarely been reported. This is a report of successful superselective embolization in a patient with Crohn's disease; this should be the initial treatment of choice in Crohn's disease in an attempt to avoid surgical resection, because repeated resections predispose patients to the development of short-bowel syndrome.

Crohn Disease↗
PubMed2005

Pathological changes after radiotherapy for primary pituitary carcinoma: a case report.

Pituitary carcinomas are extremely rare. The definition, diagnosis, therapy, and prognosis are controversial. So far, to our knowledge, there has been no report regarding pathological changes after radiotherapy for primary pituitary carcinoma. We reported a single case of a presumed prolactin staining pituitary carcinoma. We defined carcinoma by premorbid intracranial dissemination of the tumor. There were no proven extracranial metastases. The tumor was silent on PET scanning. The patient received external beam radiotherapy alone as primary therapy. Post-irradiation histology revealed that necrotic tissue made up approximately more than half. Tumor had viable cells. Probably approximately three-fifth of tumor cells were without alteration and approximately two-fifth were with degeneration. We confirmed that necrosis but no apoptosis were coexistent in the cells post irradiation for pituitary carcinoma.

Adenocarcinoma↗
PubMed2005

Detection of common bile duct stones: comparison between endoscopic ultrasonography, magnetic resonance cholangiography, and helical-computed-tomographic cholangiography.

OBJECTIVES: New modalities, namely, endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), and helical computed-tomographic cholangiography (HCT-C), have been introduced recently for the detection of common bile duct (CBD) stones and shown improved detectability compared to conventional ultrasound or computed tomography. We conducted this study to compare the diagnostic ability of EUS, MRCP, and HCT-C in patients with suspected choledocholithiasis. METHODS: Twenty-eight patients clinically suspected of having CBD stones were enrolled, excluding those with cholangitis or a definite history of choledocholithiasis. Each patient underwent EUS, MRCP, and HCT-C prior to endoscopic retrograde cholangio-pancreatography (ERCP), the result of which served as the diagnostic gold standard. RESULTS: CBD stones were detected in 24 (86%) of 28 patients by ERCP/IDUS. The sensitivity of EUS, MRCP, and HCT-C was 100%, 88%, and 88%, respectively. False negative cases for MRCP and HCT-C had a CBD stone smaller than 5mm in diameter. No serious complications occurred while one patient complained of itching in the eyelids after the infusion of contrast agent on HCT-C. CONCLUSIONS: When examination can be scheduled, MRCP or HCT-C will be the first choice because they were less invasive than EUS. MRCP and HCT-C had similar detectability but the former may be preferable considering the possibility of allergic reaction in the latter. When MRCP is negative, EUS is recommended to check for small CBD stones.

Adult↗
PubMed2005

Effect of temporal resolution on the estimation of left ventricular function by cardiac MR imaging.

The aim of this study was to investigate the effect of temporal resolution on the estimation of left ventricular (LV) function by cardiac magnetic resonance (MR) imaging using a steady-state free precession (SSFP) sequence. Left ventricular function was assessed by cine MR imaging using a segmented SSFP sequence in 10 healthy volunteers. Views per segment (VPS) were set at 8 and 20, resulting in high and low true temporal resolution, respectively. Irrespective of VPS, images were reconstructed at 40 cardiac phases, providing high apparent temporal resolution. Data were analyzed using 40, 20 and 10 phases to simulate different apparent temporal resolutions. Increasing the cardiac phases used for analysis slightly decreased mean end-systolic volume (ESV) and slightly increased mean ejection fraction (EF). No substantial difference in estimates of end-diastolic volume (EDV) was found between VPSs of 8 and 20. Imaging with a VPS of 20 yielded a larger ESV and smaller EF than imaging with a VPS of 8 when 40 phases were used. In conclusion, low true temporal resolution causes overestimation of ESV and underestimation of EF. Improvement of apparent temporal resolution mildly reduces but does not eliminate the errors caused by low true temporal resolution.

Adult↗
PubMed2005

Comparison between conventional surgery and radiotherapy for FIGO stage I-II cervical carcinoma: a retrospective Japanese study.

PURPOSE: To compare treatment outcome results of conventional surgery vs. radiotherapy (RT) for carcinoma of the uterine cervix. MATERIALS AND METHODS: A retrospective analysis was conducted of 152 patients with uterine cervical cancer radically treated with surgery or high dose-rate intracavitary brachytherapy (HDR-ICBT) with or without external RT from June 1991 to May 2004. The median follow-up time was 43.5 months (range, 1.0-130.0 months). The median age was 53 years (range, 25-81 years). There were 13 patients (9%) in stage IA, 52 (34%) in stage IB, 24 (16%) in stage IIA, and 63 (41%) in stage IIB. The conventional surgery group included 115 patients (76%) who underwent hysterectomy with pelvic lymph node dissection. Of these, 72 (63%) received postoperative radiotherapy. Thirty-seven patients (24%) were assigned to the RT group. Of these, 14 (38%) received chemoradiotherapy. Three patients with stage I received ICBT-alone without external beam irradiation. RESULTS: The 5-year cause-specific survival (CSS) rates for surgery and RT were 79.9% and 82.3%, respectively; the difference between these two treatments was not statistically significant (P = 0.8524). The differences in the survival rates between the two treatments for each of the stage I or stage II patients were also not statistically significant (P = 0.8407 for stage I and P = 0.6418 for stage II). CONCLUSIONS: This retrospective study suggests that RT results in compatible survival with conventional surgery for patients with stage I-II cervical carcinoma.

Adenocarcinoma↗