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Biomedical subjects

K Tomoda

Publications and source records attributed to K Tomoda.

At least 163 records · Page 9Linked to original sources
PubMedDate not supplied

Contrast-enhanced MR imaging of intrahepatic cholangiocarcinoma: pathologic correlation study.

The authors describe the enhanced magnetic resonance (MR) imaging appearance of intrahepatic cholangiocarcinoma. The MR images of eight patients with intrahepatic cholangiocarcinoma who underwent MR examination within 3 weeks before partial hepatectomy were retrospectively studied. The MR images, including a dynamic study, were compared directly with pathologic and histologic findings. The peripheral region of the medullary subtype of cholangiocarcinoma, with many tumor cells, showed greater enhancement relative to liver parenchyma in the early phase. The peripheral region of the scirrhous subtype, with fewer tumor cells showed less enhancement in the early phase. In one patient, the thin rim of the medullary tumor showed less enhancement in the late phase, and this rim corresponded to the peripheral region of the medullary tumor with many tumor cells. The central region of tumors with a large amount of fibrous tissue showed prolonged enhancement in the late and delayed phases. The thin rim of liver parenchyma around the tumor showed less enhancement in the early phase and greater enhancement in the late phase; this rim corresponded to congestive liver parenchyma with dilated sinusoids. Intrahepatic cholangiocarcinoma shows various enhancement patterns, which depend on both the histologic subtype and the degree and distribution of fibrosis within the tumor.

Aged↗
PubMedDate not supplied

MR imaging of mixed hepatocellular and cholangiocellular carcinoma.

Two patients with mixed hepatocellular and cholangiocellular carcinoma underwent partial hepatectomy after magnetic resonance (MR) imaging. Correlation is made with the histopathologic manifestations. In both cases the tumors showed relative low signal intensities on T1-weighted spin-echo (SE) images and high signal intensities on T2-weighted SE images. Dynamic MR imaging showed the enhancement from the periphery of the tumor to the inner area gradually and the enhancement continued into the delayed phase. With both cases fibrosis was marked in the inner area of the tumor compared to the peripheral area. The extent and degree of fibrotic tissue is considered to reflect the enhancement on dynamic MR imaging.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Hepatocellular carcinoma: efficacy of transcatheter oily chemoembolization in relation to macroscopic and microscopic patterns of tumor growth among 100 patients with partial hepatectomy.

PURPOSE: To evaluate the efficacy of transcatheter oily chemoembolization (TOCE) for hepatocellular carcinoma (HCC) on the basis of microscopic and macroscopic findings postembolization. METHODS: HCCs ranging in size from 0.5 to 13 cm (mean 3.6 cm) were obtained from partial hepatectomies of 100 consecutive patients who had undergone TOCE between 20 and 246 days (mean 59.5 days) prior to surgery. The efficacy of TOCE was assessed on the basis of the necrotic to live cell ratio of the tumors. The microscopic pattern of tumor growth was grouped into expanding type (complete capsule formation) and replacing type (incomplete or no capsule). There were five types of macroscopic groupings: single nodule, single nodule with extranodular growth (SNE), contiguous and noncontiguous multinodular, and massive growth type. RESULTS: Among 79 cases with the expanding type, 29 (37%) had 100% HCC necrosis, but none with 100% necrosis were in the replacing type. By macroscopic grouping, the efficacy of TOCE decreased from the single nodule type (50% of patients had 100% necrosis) to the SNE type (21%), and the other types (9%). CONCLUSION: TOCE appears to be most efficacious for HCC with the expanding growth pattern and HCC forming single nodules. Poor results are to be expected in HCC of replacing growth type and multinodular or massive growth types.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Optimal phases of dynamic CT for detecting hepatocellular carcinoma: evaluation of unenhanced and triple-phase images.

BACKGROUND: To determine the optimal phases of dynamic computed tomography (CT) for detecting hepatocellular carcinoma (HCC). METHODS: Fifty-two patients with 85 HCC nodules were examined by means of unenhanced and triple-phase CT images of the whole liver. The time for obtaining the arterial-phase images was 25-55 s after intravenous bolus injection of contrast material, the time for obtaining the portal venous-phase images was 65-100 s, and the time for obtaining late-phase images was 145 s to 4 min. Detectability of the HCC nodules for all phases was statistically compared. RESULTS: The detection rates for the arterial- and late-phase images were significantly higher than for the unenhanced and portal venous-phase images (p < 0.01). The combination of arterial- and late-phase images showed the same number of HCC nodules in the same number of patients as did the combination of unenhanced and triple-phase images. CONCLUSION: The combination of the arterial- and late-phase imagings was best for detecting HCC nodules.

Adult↗
PubMedDate not supplied

CO2 laser stapedotomy: is it practical?

The argon laser has been described as an instrument capable of performing stapedotomy for otosclerosis. Because of the possibility of cost ineffectiveness and damage to the saccule using the argon laser, this study was undertaken to ascertain the possibility of using the CO2 laser for stapedotomy. the operation was done on seven cats, and the resulting histopathologic findings were studied. Stapedotomy was also performed with the CO2 laser on human cadaver temporal bones to measure temperature changes in the vestibule and to develop guidelines for the laser's use in humans. The authors' results indicated that the CO2 laser can be used effectively and safely in cats and should be considered for human use.

Animals↗
PubMedDate not supplied

Factors influencing collagen-induced autoimmune ear disease.

In 1981, the authors described a type II collagen-induced autoimmune ear disease (CIAED) model. The purpose of this study was to gather further evidence that this is a sound animal model to use in evaluating inner ear diseases. The temporal bone lesions of CIAED in Lewis and Wistar rats were characterized by the presence of sensorineural hearing loss with mild atrophy of the organ of Corti and spiral ganglion degeneration, vestibular dysfunction with vacuolar degeneration of the crista ampullaris, otospongiosis-like lesions in the tympanic annules, cochlear vasculitis, and eustachian tube disease. Both cellular and humoral immune responses to type II collagen were demonstrated. The induction of ear lesions depends on many factors. In general, animals immunized with antigens in complete Freund's adjuvant showed relatively more severe lesions than animals immunized with antigens in incomplete Freund's adjuvant, but the duration of the immunization seems to be a more important factor in reproducing severe lesions. The strain and the source of the animals are also important factors in autoimmune inner ear diseases, as is the condition of the host animals. Subclinical or clinical mycoplasma infection in the rat markedly reduced the incidence and severity of lesions in type II collagen-induced arthritis. Many researchers did not consider sialoductal adenovirus, widely present among laboratory rats, a lesion-producing factor in rats. Although many factors influence the induction and severity of CIAED, these animal models provide an excellent new avenue of inner ear research.

Animals↗
PubMedDate not supplied

Endovascular stent graft placement for patients with aortic aneurysm and end-organ dysfunction.

Endovascular stent grafts (ESGs) for the treatment of aortic aneurysm is becoming popular because it is less invasiveness for the patient. This new modality seems to be especially useful for treating high risk patients, such as those with end-organ dysfunction. In this study we retrospectively analyzed the results of ESG placement for patients with renal or hepatic dysfunction. From January 1996 to December 1997, six patients with end-organ dysfunction (two with descending thoracic aneurysm and four with abdominal aneurysm) underwent ESG placement. Five of these patients had renal dysfunction, with serum creatinine levels of 2.0 mg/dl or greater, and the remaining patient had hepatic dysfunction with a prothrombin time less than 60%. One of the patients also had severe atherosclerotic disease with a history of multiple brain infarctions. All the patients received custom made endovascular spiral Z stents covered with a woven Dacron (DuPont Co., Wilmington, DE) graft, which was delivered via a femoral artery under local anesthesia. None of the patients showed significant changes in renal or hepatic function after the procedure. None of the five patients with renal dysfunction needed hemodialysis after ESG placement, although the mean preoperative level of serum creatinine and blood urea nitrogen was 3.4 mg/dl and 42.0 mg/ dl, respectively. All the patients left the recovery room on postoperative day 1. These results indicated that endovascular stent graft placement is extremely useful in the treatment of aortic aneurysm patients with end-organ dysfunction.

Aged↗
PubMedDate not supplied

3DFT-FISP MRI with gadopentetate dimeglumine in differential diagnosis of small liver tumors.

OBJECTIVE: We assessed the value of dynamic sequential three-dimensional Fourier transformation (3DFT) MRI in differentiating various types of small liver tumors. MATERIALS AND METHODS: Forty-seven patients with 65 liver masses < 3 cm in size (42 hepatocellular carcinomas, 11 hemangiomas, 12 metastatic tumors) were studied by 3DFT fast imaging with steady-state precession (FISP) MRI [TR(ms)/TE(ms)/flip angle (degree): 20/8/30]. The slab thickness was 21-35 mm, and there were seven partitions. The 3DFT-FISP MR images were obtained immediately after 0.1 mmol/kg of gadopentetate dimeglumine was administered intravenously over 2-3 s (early phase), 60 s after (late phase I), and 120 s after (late phase II). RESULTS: Eighty-six percent of small hepatocellular carcinomas showed hyperintense enhancement relative to the surrounding liver parenchyma and iso- or hypointense enhancement with or without capsular enhancement in the late phase. Eighty-two percent of small hemangiomas showed peripheral globular enhancement in the early phase and total hyperintense or peripheral enhancement in the late phases. Ninety-two percent of the small metastatic liver tumors showed doughnut-like ring enhancement in the early phase. CONCLUSION: By dynamic 3DFT-FISP MRI, we were able to accurately evaluate the hemodynamics and morphological findings of each type of small liver tumor.

Aged↗
PubMedDate not supplied

Intramural invasion of gastric cancer: evaluation by CT with water-filling method.

OBJECTIVE: Our goal was to clarify the ability of CT to evaluate intramural invasion of gastric cancer. MATERIALS AND METHODS: We reviewed bolus-enhanced CT images performed with orally administered 400-600 ml of water in 59 early gastric cancers and 22 advanced gastric cancers mimicking early gastric cancers macroscopically. RESULTS: CT was able to reveal 49% of early gastric cancers and 68% of advanced gastric cancers mimicking early cancers. Twenty-seven gastric tumors were detected in two or three layered structure of wall. Morphologic features of early gastric cancers are strong enhancement without wall thickening and thickened inner layer with normal middle and outer layers. Morphologic features of early advanced gastric cancers are a thickened wall with disappeared middle and outer layers and transmural enhancement with wall thickening. If one of these features was used to predict whether the tumor was early or early advanced gastric cancer in detected cases, specificity was 93-100%, sensitivity was 7-72%, and positive predictive value was 80-100%. CONCLUSION: We evaluated whether the wall pattern of gastric tumors on CT can provide useful information about intramural invasion.

Adult↗
PubMedDate not supplied

Helical CT angiography of living renal donors: comparison with 3D Fourier transformation phase contrast MRA.

PURPOSE: The purpose of this study was to determine whether helical CT angiography (CTA) or MR angiography (MRA) is the optimal method to use as a preoperative examination for anatomic arterial assessment of living renal donors. METHOD: Eighteen candidates to be renal donors underwent helical CTA, 3D Fourier transformation phase contrast (3D-FT-PC) MRA, and digital subtraction angiography (DSA). The CTA and MRA were interpreted separately by three readers independently, and these results were correlated with the findings of DSA. RESULTS: DSA showed nine accessory renal arteries and 10 prehilar branches. CTA revealed seven or eight accessory renal arteries. MRA showed six or seven accessory arteries. Of 10 prehilar branches, 7-9 branches were detected with CTA and 5-8 branches with MRA. CONCLUSION: Helical CTA is superior to 3D-FT-PC MRA for evaluating the arterial anatomy of living renal donors.

Adult↗