Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 865 records · Page 48Linked to original sources

PubMedDate not supplied

Endoscopic ultrasonography in the assessment of colonic wall invasion by adjacent diseases.

For assessing the direct invasion of the colonic wall by pelvic or abdominal tumors, endoscopic ultrasonography was performed prospectively in patients who were suspected of having colonic wall invasion by barium enema. Three patients with ovarian cancer, two with endometriosis, and one with pancreatic cancer were included in this study. Preoperative endoscopic ultrasonography (EUS) revealed the relationship between the tumor and the colon in all cases. A surgical procedure was performed in all patients: resection of the tumor and a portion of the invaded colon (4) and removal of the tumor (only adhesion) (2). A correct preoperative diagnosis of the depth of tumor invasion was obtained in five of the six (83%) cases. In patients with pelvic or abdominal tumors, preoperative EUS may be useful for evaluating the presence and the degree of invasion of the colonic wall by the tumor.

Abdominal Neoplasms↗

PubMedDate not supplied

Coil embolization of arterioportal fistula that developed after partial gastrectomy.

A 51-year-old man suffered from bleeding esophageal varices. He had undergone partial gastrectomy for gastric cancer 1 year before. An extrahepatic arterioportal fistula and resultant portal hypertension were found. We successfully performed transarterial embolization of the fistula using stainless steel coils. Portal hypertension improved dramatically.

Angiography↗

PubMedDate not supplied

Measurement of the apparent diffusion coefficient in intraductal mucin-producing tumor of the pancreas by diffusion-weighted echo-planar MR imaging.

BACKGROUND: We investigated whether diffusion-weighted echo-planar magnetic resonance (MR) imaging can help differentiate intraductal mucin-producing tumors of the pancreas from other cystic lesions. METHODS: Diffusion-weighted echo-planar MR imaging was performed in patients with mucin-producing tumors (n = 19), pseudocysts (n = 9), chronic pancreatitis with diffuse main pancreatic dilatation (n = 5), and serous cystadenomas (n = 2). Images were obtained with diffusion sensitizing gradients of 30, 300, and 900 s/mm2. The apparent diffusion coefficient (ADC) was calculated. RESULTS: The mean (+/- standard deviation) ADCs of mucin-producing tumors (2.8 x 10(-3) mm2/s +/- 1.0 x 10(-3)), pseudocysts (2.9 x 10(-3) mm2/s +/- 1.2 x 10(-3)), dilated main pancreatic duct in chronic pancreatitis (3.3 x 10(-3) mm2/s +/- 1.2 x 10(-3)), serous cystadenomas (2.9 x 10(-3) and 2.6 x 10(-3) mm2/s), and cerebrospinal fluid (3.5 x 10A(-3) mm2/s +/- 1.1 x 10(-3)) were not statistically different. CONCLUSION: It is difficult to differentiate between mucin-producing tumors and other cystic lesions by ADC measurements when using diffusion-weighted echo-planar MR imaging.

Adult↗

PubMedDate not supplied

Gallbladder torsion: case report.

Torsion of the gallbladder (GB) is a rare, acute abdominal condition. The treatment of choice is cholecystectomy. Even with recent advances in radiologic imaging modalities, it is difficult to make a correct preoperative diagnosis of GB torsion. We report a case of GB torsion with a retrospective review of the radiologic findings of magnetic resonance imaging, computed tomography, and ultrasonography. Those findings were compared with the histopathologic findings of the surgical specimen. The radiologic findings in our case were useful for making a preoperative diagnosis of GB torsion. We postulate the characteristic magnetic resonance findings and discuss discrepancies in the evaluations of the GB wall.

Adult↗

PubMedDate not supplied

Abdominal cystic tumors containing small amount of fat in the septa: report of two cases.

We present two cases of abdominal cystic tumors containing small amounts of fat in their septa. Although the final pathologic diagnoses of these tumors were cystic lymphangioma and angiomatosis, the computed tomographic and magnetic resonance imaging features were almost identical and indistinguishable; a purely cystic mass around the region of the pancreas head associated with little mass effect on the surrounding organs and septa containing a radiologically evident fatty component. Radiologists should be aware of these two entities as differential diagnoses of abdominal cystic masses containing small amounts of septal fat.

Abdominal Neoplasms↗

PubMedDate not supplied

Metastatic adrenal tumor from clear-cell renal cell carcinoma: a pitfall of chemical shift MR imaging.

We present a case of adrenal metastasis from clear-cell renal cell carcinoma in which presence of a small amount of fat was shown on chemical shift gradient-echo magnetic resonance imaging. Radiologists should be aware that signal loss of the adrenal tumor on out-of-phase gradient-echo images does not always suggest the diagnosis of benign adenoma, particularly in patients with a history of renal cell carcinoma.

Adenocarcinoma, Clear Cell↗

PubMedDate not supplied

Sclerosed hemangioma of the liver.

We report the radiologic findings of sclerosed hemangioma (SH), a rare variant of hepatic hemangioma. Dynamic contrast-enhanced computed tomography showed a hypodense mass in the liver with delayed enhancement. T2-weighted magnetic resonance imaging showed the mass as hypointense in relation to cerebrospinal fluid. The final diagnosis of SH was made pathologically. Although SH is rare, understanding its radiologic appearance is important to avoid unnecessary surgery and should be included in the differential diagnoses of hepatic lesion with delayed enhancement.

Aged↗

PubMedDate not supplied

Hepatocellular carcinoma with sarcomatous change: characteristic findings of two-phased incremental CT.

BACKGROUND: Because of its poor prognosis, the diagnosis of hepatocellular carcinoma with sarcomatous change (HCCSC) is clinically important. The purpose of this study is to elucidate the characteristic CT findings of HCCSC. METHODS: Two-phased dynamic incremental CT images of six histologically proven HCCSC were retrospectively reviewed. RESULTS: All tumors (100%) exhibited peripheral enhancement on delayed CT images. Lymphadenopathy was observed in 100% (six of six patients); intrahepatic metastases, in 83% (five of six). Both metastatic lesions showed findings similar to those of the primary hepatic tumors, such as peripheral enhancement. Histopathological delayed and/or prolonged peripherally enhanced areas consisted of viable cancer cells with sarcomatous changes. CONCLUSIONS: The appearance of HCCSC on CT is that of an irregularly demarcated intrahepatic mass with delayed or prolonged peripheral enhancement, frequently with intrahepatic metastases and lymphadenopathy.

Aged↗

PubMedDate not supplied

Radiologically identifiable intratumoral portal vein in intrahepatic cholangiomas: a diagnostic pitfall.

BACKGROUND: Although intratumoral patent portal vein (ITPV) is one of the characteristic features of benign hepatic lesions, ITPVs can be demonstrated in malignant tumors. We present the spectrum of MR and CT findings of ITPV identified in intrahepatic cholangiomas with pathological correlations. METHODS: The ultrasound, CT and/or MRI findings of pathologically-confirmed intrahepatic cholangiomas were reviewed and correlated with surgical specimen or autopsy findings. RESULTS: Intratumoral patent vessels were radiographically-demonstrated in 5 patients with intrahepatic cholangiomas. All intratumoral vessels were secondary or tertiary order portal vein branches. Some wall thickening was identified on pathological examinations. CONCLUSION: The radiological demonstration of intratumoral portal vein is not a specific sign of benignity. In the case of a hepatic tumor with a patent portal tract, cholangioma should be considered, as well as benign tumors or lymphoma.

Adenoma, Bile Duct↗

PubMedDate not supplied

Primary malignant lymphoma in the porta hepatis: a case report.

A case of primary lymphoma in the porta hepatis is presented here. Cholangiography, angiography, ultrasonography and computed tomography suggested the presence of a mass in the porta hepatis, but all these failed to demonstrate the tumor clearly. Magnetic resonance imaging was very useful in defining the characteristics of the tumor and in delineating its extent, though it was not specifically diagnostic.

Aged↗

PubMedDate not supplied

MR imaging of hepatocellular carcinomas: effect of Cu and Fe contents on signal intensity.

BACKGROUND: To elucidate the metallic factors contributing to the signal intensities of hepatocellular carcinoma (HCC) on T1-weighted magnetic resonance (MR) images and to determine whether or not changes in signal intensity contribute to the diagnosis of histological grading of HCC. METHODS: In 35 patients immediately after surgery, the quantities of water, lipid, copper (Cu), iron (Fe), and manganese (Mn) were determined in HCCs and the surrounding hepatic parenchyma. The correlations among these findings, the histopathological findings, and the signal intensities of T1-weighted MR images were evaluated. RESULTS: Among the 35 HCCs, 12 (34%) were of high intensity, 14 (40%) were isointense, and 9 (26%) were of low intensity on T1-weighted images versus the surrounding hepatic parenchyma. The paramagnetic ions, which contributed to the signal intensity patterns, were assumed to be Cu in HCCs (30.5 +/- 52.9 microg/g ww), and Fe in the livers (106.2 +/- 86.8 microg/g ww) and HCCs (87.7 +/- 49.1 microg/g ww). In 12 HCCs with high intensity, one was grade I, eight were grade II, and three were grade III according to Edmondson-Steiner's histopathological classification. CONCLUSIONS: Signal intensity and signal intensity patterns alone cannot be signs of low-grade malignancy because of the Fe in livers and in HCCs.

Aged↗

PubMedDate not supplied

Helical CT evaluation of arterial invasion in pancreatic tumors: comparison with angiography.

BACKGROUND: Although helical computed tomography (HCT) has been widely employed for the evaluation of pancreatic tumors, its capability in the diagnosis of peripancreatic arterial invasion has not been established. METHODS: HCT with a sequential cine-display was carried out in 34 patients with solid pancreatic tumors and 28 control subjects without angiographic abnormality. The HCT scans were compared with angiograms. RESULTS: All major arteries (celiac, superior mesenteric, splenic, gastroduodenal) and superoanterior pancreaticoduodenal arteries were well demonstrated by HCT in control subjects. However, posterior pancreaticoduodenal arcades and other smaller arteries were poorly identified. Although 19 major arterial invasions were equally diagnosed by HCT and angiography in patients with pancreatic tumors, only 4 of 11 minor arterial invasions were correctly diagnosed by HCT. CONCLUSIONS: Although HCT has some limitations in the evaluation of minor peripancreatic arteries, it can provide enough information for making a decision about conducting pancreatic surgery.

Aged↗

PubMedDate not supplied

Comparison of helical CT and MR imaging in detecting and staging small pancreatic adenocarcinoma.

BACKGROUND: To compare the value of helical computed tomography (CT) and various pulse sequences of magnetic resonance (MR) imaging in the detection and staging of small pancreatic adenocarcinoma. METHODS: Small pancreatic adenocarcinomas (< or = 2 cm in diameter) in eight patients were evaluated with both helical CT and MR imaging. Five MR imaging pulse sequences that included fat-suppressed T1-weighted images and dynamic study using fast multiplanar spoiled gradient-recalled technique were compared for the tumor detectability. To evaluate the tumor vascularity, angiographic findings were also investigated. RESULTS: Helical CT delineated the tumor in five cases, and MR imaging depicted the tumor in seven cases. MR imaging could detect the tumor of 0.8 cm in diameter clearly. Although helical CT and dynamic MR imaging missed the tumor of 2 cm with relative hypervascularity, fat-suppressed T1-weighted MR imaging demonstrated it precisely. As for the tumor staging, MR imaging was equal or slightly superior to helical CT. CONCLUSION: MR imaging is the first modality of choice to evaluate small pancreatic adenocarcinoma, and fat-suppressed T1-weighted images and dynamic study must be performed.

Adenocarcinoma↗

PubMedDate not supplied

Uterine lipoleiomyoma: MRI appearances.

A case of uterine lipoleiomyoma demonstrated on computed tomography (CT) and magnetic resonance imaging (MRI) is described and usefulness of MRI is discussed in diagnosing this entity.

Diagnosis, Differential↗

PubMedDate not supplied

Chronic expanding hematoma of the spleen caused by angiomyolipoma in a patient with tuberous sclerosis.

We report a case of a chronic expanding hematoma caused by an angiomyolipoma of the spleen in a patient diagnosed with tuberous sclerosis in infancy. Computed tomography showed large bilateral renal angiomyolipomas. A splenic mass that increased in size during the follow-up period of 62 months was also noted. A large subcapsular hematoma of the spleen finally developed, and a splenectomy was performed. The splenic mass consisted of a chronic hematoma with prominent granulation tissue, which was considered to be caused by repeated bleeding from a small angiomyolipoma in the spleen.

Adult↗

PubMedDate not supplied

Pseudolesion in segment II of the liver observed on CT during arterial portography caused by the aberrant left gastric venous drainage.

A rare case with a pseudolesion in segment II of the liver observed on computed tomography (CT) during arterial portography caused by the aberrant left gastric venous drainage is presented. Close observation of the celiac angiography was helpful in recognizing this pseudolesion. Selective catheterization of the left gastric artery and CT during its venous phase confirmed the etiology of the pseudolesion.

Fatal Outcome↗

PubMedDate not supplied

Fat detection in granular-cell renal cell carcinoma using chemical-shift gradient-echo MR imaging: another renal tumor that contains fat.

Preoperative chemical-shift magnetic resonance images in a 56-year-old man suggested the presence of microscopic fat in the tumor. The surgical specimen showed a granular-cell renal cell carcinoma with papillary architecture, associated with abundant fat-containing foamy histiocytes in the interstitium. The radiologist should include this entity in the differential diagnoses of renal tumors that contain microscopic fat.

Adipose Tissue↗

PubMedDate not supplied

Complications encountered with a transfemorally placed port-catheter system for hepatic artery chemotherapy infusion.

A port-catheter system was implanted via femoral artery access for hepatic artery chemotherapy infusion. Implantation was attempted in 90 patients and was successful in 88. Blood flow redistribution was performed using embolization coils. In the first ten patients a soft heparin-coated infusion catheter was used. For the following 78 patients we used a stiffer catheter coated with fluorine-acryl-styrene-urethane-silicone (FASUS) copolymer. The catheter was connected to a port implanted subcutaneously below the level of the inguinal ligament. Complications during the procedure and after placement were observed in 7 of 90 patients and 24 of 88 patients, respectively. These included catheter obstruction (11%), dislocation of the catheter tip (10%), drug toxicity (5.7%), and catheter infection (3.4%). In 6 of 10 patients with catheter obstruction, recanalization of the port system was achieved. In 7 of 9 patients with dislocation of the indwelling catheter tip, replacement of the port system was successful. Our complications appear to be comparable with those encountered with the subclavian/brachial approach when the new catheter coating is used. Notable is the avoidance of cerebral infarcts.

Adolescent↗