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Biomedical subjects

M Kanematsu

Publications and source records attributed to M Kanematsu.

At least 55 records · Page 3Linked to original sources
PubMed1998

Adenomatous hyperplasia with unusual imaging findings at combined helical CT hepatic arteriography and CT during arterial portography.

We examined a patient with a hepatocellular carcinoma and multiple adenomatous hyperplasias in the cirrhotic liver. Helical CT hepatic arteriography (CTA) showed the adenomatous hyperplasias as areas of discrete hypoattenuation, and the combined CT during arterial portography (CTAP) showed corresponding areas of subtle hyperattenuation. Such imaging findings at combined CTA and CTAP were seen in only one patient in a series of more than 80 patients in whom we performed angiographically-assisted CT. We demonstrate these unusual imaging findings of adenomatous hyperplasia in the report.

Adenoma↗
PubMed1998

Hepatodiaphragmatic portosystemic shunt in cirrhosis.

A case of an unusual form of hepatodiaphragmatic portosystemic shunt arising from the periphery of left posterosuperior portal vein branch, running beneath the inferior aspect of left hemidiaphragm and draining into the left lateral abdominal wall is demonstrated and assessed with digital subtraction portography, maximum-intensity-projection images reconstructed from helical CT during arterial portography and pulsed Doppler sonography with flow velocity measurement. This is a reported case of this unusual intrahepatic portosystemic shunt and discussion on the utility of current radiological techniques.

Abdominal Muscles↗
PubMed1998

Focal hepatic lesion detection: comparison of four T2-weighted MR imaging pulse sequences.

PURPOSE: To evaluate T2-weighted magnetic resonance (MR) imaging with conventional spin-echo, breath-hold fast spin-echo, respiratory-triggered fast spin-echo, and breath-hold multishot spin-echo echo-planar sequences for detection of focal hepatic lesions. MATERIALS AND METHODS: T2-weighted MR images obtained with the four sequences in 56 patients with 107 solid and 124 nonsolid lesions were retrospectively analyzed. Image review was conducted on a liver segment-by-segment basis; a total of 408 liver segments were reviewed separately and independently for solid and nonsolid lesions by three radiologists. Diagnostic accuracy was evaluated with receiver operating characteristic analysis. RESULTS: Lesion-to-liver contrast-to-noise ratio was highest with multishot echo-planar images of both solid and nonsolid lesions. Diagnostic accuracy for solid lesions was statistically significantly better with conventional spin-echo images than with any other type of image (P < .0001). Diagnostic accuracy for nonsolid lesions was statistically significantly better with respiratory-triggered fast spin-echo images than with any other type of image (P < .0001). Image quality was best with breath-hold fast spin-echo images. CONCLUSION: Conventional spin-echo MR imaging should not be replaced with breath-hold fast spin-echo or multishot spin-echo echo-planar imaging, despite the shorter acquisition times that are possible with the latter two sequences.

Female↗
PubMed1998

Association of a polymorphism of the transforming growth factor-beta1 gene with genetic susceptibility to osteoporosis in postmenopausal Japanese women.

Transforming growth factor-beta (TGF-beta) is both abundant in bone and an important regulator of bone metabolism. A T-->C transition at nucleotide 29 in the signal sequence region of the TGF-beta1 gene results in a Leu-->Pro substitution at amino acid position 10. The possible association of this polymorphism with bone mass and the prevalence of osteoporosis has now been investigated in a total of 287 postmenopausal women from two regions (Obu City, Aichi Prefecture, and Sanda City, Hyogo Prefecture) of Japan. A significant association of TGF-beta1 genotype with bone mass was detected in both populations; bone mineral density (BMD) at the lumbar spine was greater in individuals with the CC genotype than in those with the TT or TC genotype. The frequency of vertebral fractures was significantly lower in individuals with the CC genotype than in those with the TC or TT genotypes. For each region, multivariable logistic regression analysis revealed that the frequency of the T allele was significantly higher in subjects with osteoporosis than in controls. Also, the serum concentration of TGF-beta1 in individuals with the CC genotype was significantly higher than that in age-matched subjects with the TC or TT genotype in osteoporotic or osteopenic as well as healthy control groups. These results suggest that the T/C polymorphism of the TGF-beta1 gene is one of the genetic determinants of bone mass and that the T allele is an independent risk factor for the genetic susceptibility to osteoporosis in postmenopausal Japanese women. Thus, analysis of the TGF-beta1 genotype may be useful in the prevention and management of osteoporosis.

Adult↗
PubMed1998

Nondiseased portal perfusion defects adjacent to the right ribs shown on helical CT during arterial portography.

OBJECTIVE: The purpose of our study was to assess the frequency and imaging characteristics of nonpathologic portal perfusion defects in subcapsular liver parenchyma adjacent to the right ribs as seen on CT hepatic arteriography combined with helical CT during arterial portography (CTAP). MATERIALS AND METHODS: From January 1994 to June 1997, helical CTAP and CT hepatic arteriography were performed in 94 patients with suspected malignant hepatic tumors. The patient group comprised 66 men and 28 women ranging from 37 to 83 years old (mean, 64 years old). Three radiologists retrospectively reviewed the images obtained by CTAP to evaluate portal perfusion defects adjacent to the right ribs for location, shape, size, and correlation with findings seen on CT hepatic arteriography. RESULTS: We identified 16 nonpathologic portal perfusion defects adjacent to the right eighth (n = 1), ninth (n = 12), and tenth (n = 3) ribs in 12 (13%) of 94 patients. The shapes of the 16 defects were circular (n = 1), oval (n = 7), wedge (n = 3), and irregular (n = 5). The defects were 10-30 mm in diameter (mean, 16.9 mm). In four (25%) of 16 locations, CT hepatic arteriography showed poorly identified, homogeneous, irregularly shaped areas of contrast enhancement corresponding to the defects seen on CTAP. The portal perfusion defects were proven to be nonpathologic on definitive surgery in four patients and on follow-up radiography in eight patients. CONCLUSION: Helical CTAP may show nonpathologic portal perfusion defects adjacent to the right ribs. Most defects did not appear circular but rather were oval, irregular, or wedge-shaped. CT hepatic arteriography infrequently showed corresponding findings. Radiologists should recognize this potential pitfall when interpreting images obtained by helical CTAP.

Adult↗
PubMed1998

[MR cholangiopancreatography with single-shot fast-spin-echo sequences].

Imaging quality of MR cholangiopancreatography (MRCP) has recently made a great advance, and MRCP plays an important part in the diagnosis of pancreticobiliary diseases. To obtaining excellent-quality MRCP images, three conditions are required: fluid-to-background contrast, high spatial resolution, and suppression of respiratory motion artifacts. Respiratory motion artifacts, whose suppression is especially important for MRCP, can be controlled by the use of breath-holding, signal averaging, or respiratory triggering. These images are implemented in either single-slice technique or multi-slice technique. We have performed MRCP prior to endoscopic retrograde cholangiopancreatography (ERCP) in more than 100 patients. MRCP images were obtained as maximum-intensity-projection (MIP) reconstruction images and thick-slice projection images by using single-shot fast-spin-echo sequence, and MIP reconstruction images by using respiratory-triggered fast-spin-echo sequence. We reviewed MRCP imaging with single-shot fast-spin-echo sequences.

Aged↗
PubMed1997

Role of glucocorticoid on interleukin-6-induced cellular functions in the mouse macrophage cell line (Mm 1).

To discover a role of glucocorticoid on interleukin-6 (IL-6)-induced responses of a macrophage, we investigated the effect of IL-6 and/or dexamethasone (Dex) on cellular functions of a mouse macrophage cell line (Mm1 cells). The results obtained were as follows. (1) Dex decreased the accumulation of tumor necrosis factor-alpha induced by IL-6, whereas nitric oxide production was enhanced by Dex. Moreover, the enhancement of nitric oxide production could be demonstrated to be associated with stimulation of iNOS mRNA expression by the Dex treatment. (2) Cytotoxic activity of Mm1 cells on mouse B16 melanoma cells was much more enhanced by the co-treatment of IL-6 with Dex than IL-6 treatment alone. (3) Dex promoted further the suppression of proliferation induced by IL-6. (4) DNA fragmentation, introduced by the treatment of cells with IL-6, was further enhanced in the presence of Dex.

Animals↗
PubMed1997

A case of liver metastasis from colon cancer masquerading as focal sparing in a fatty liver.

Focal sparing in diffusely fatty liver is a well recognized entity. However, it occasionally creates some problems in the diagnosis of hepatic mass lesions. We recently experienced a case of liver metastasis from colon cancer which appeared as a wedge-shaped hyperdense area on non-enhanced CT (computed tomography). Other imaging techniques also demonstrated a wedge-shaped area which was difficult to distinguish from mere focal sparing in the fatty liver. CT arteriography and dynamic magnetic resonance images were useful for diagnosing this metastatic tumor. CT during arterial portography showed a wedge-shaped ischemic area in the anterior segment caused by intrahepatic portal vein blockade. The histological findings eventually revealed that the tumor, an adenocarcinoma, was surrounded by fibrotic tissue that mimicked focal sparing. We present the radiological features of this case and discuss how to arrive at a correct diagnosis.

Adenocarcinoma↗
PubMed1997

Hepatocellular carcinoma: the role of helical biphasic contrast-enhanced CT versus CT during arterial portography.

PURPOSE: To assess the role of helical biphasic computed tomography (CT) versus CT during arterial portography (CTAP) in the detection of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Helical biphasic CT and CTAP examinations were performed in 33 patients with biopsy-proved HCC. Three blinded radiologists retrospectively evaluated portal venous phase images, portal venous phase plus hepatic arterial phase images (helical biphasic CT), and CTAP plus portal venous phase images at separate sittings. In 23 patients with pathologic proof of total tumor burden, the readers conducted a consensus matched-pair reading to determine the sensitivity of each method. RESULTS: In the 23 patients with a proved tumor burden of 100 HCC lesions, the observers detected 74 tumors on portal venous phase images, 82 tumors on hepatic arterial phase images, 87 tumors on CTAP images, 87 tumors on helical biphasic CT images, and 96 tumors on portal venous phase plus CTAP images. Hepatic arterial phase images and CTAP images, respectively, depicted 13 and 23 tumors not seen on portal venous phase images in eight (35%) and 13 (56%) of 23 patients. Ten tumors were seen on portal venous phase images but not on CTAP images owing to the presence of central tumors or segmental portal venous thrombi that obstructed the flow of contrast material to more peripheral portions of the liver. CONCLUSION: The addition of hepatic arterial phase imaging to portal venous phase imaging (helical biphasic CT) provided an incrementally increased yield in HCC tumor detection. Helical biphasic CT should be used as the initial screening examination in patients with suspected or known HCC.

Adult↗
PubMed1997

Three-dimensional CT demonstration of intrahepatic portosystemic venous shunt draining into the inferior vena cava.

An unusual form of intrahepatic portosystemic venous shunt draining into the inferior vena cava was demonstrated using three-dimensional images reconstructed from spiral CT during arterial portography, colour Doppler ultrasonography with flow velocity measurement, and digital subtraction portovenography. The utilization of modern radiological techniques in evaluating intrahepatic portosystemic venous shunts is discussed.

Aged↗
PubMed1997

Interaction between nitric oxide synthase and cyclooxygenase pathways in osteoblastic MC3T3-E1 cells.

Interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF-alpha) have been implicated in the pathogenesis of osteoporosis. These proinflammatory cytokines induce both cyclooxygenase (COX) and nitric oxide synthase (NOS) with the release of prostaglandin (PG) and NO, respectively. The present study was undertaken to examine the interaction between COX and NOS pathways and their role in the regulation of osteoblastic function in MC3T3-E1 cells. Addition of IL-1 alpha and TNF-alpha induced a marked increase in the production of both NO and PGE2. Reverse transcription-polymerase chain reaction analysis showed that the increase in NO production was preceded by the expression of inducible NOS mRNA. The temporal profile of PGE2 production revealed a biphasic pattern: the first small peak at 3 h was caused by de novo synthesis of PGE2 through inducible COX (COX-2) mRNA, while the subsequent progressive accumulation of PGE2 was mediated through the activation of COX pathway by NO since (1) aminoguanidine (AG), a selective inhibitor of inducible NOS, significantly suppressed the PGE2 production by IL-1 alpha and TNF-alpha, (2) NOC-18, an NO donor, reversed this suppression, and (3) NOC-18 increased PGE2 production by itself. The increase in NO production in response to IL-1 alpha and TNF-alpha was further stimulated by aspirin and inhibited by exogenous addition of PGE2, suggesting that PGE2 produced by the cytokines, in turn, negatively modulates NO production. IL-1 alpha and TNF-alpha inhibited alkaline phosphatase (ALP) activity, which was significantly reversed by AG. NOC-18 not only suppressed ALP activity by itself but also blocked the effect of AG, suggesting the role of NO in the inhibition of ALP activity. PGE2 decreased ALP activity, and the inhibitory effect of NOC-18 was attenuated in the presence of aspirin, suggesting the involvement of PGE2 in the negative modulation of ALP activity by NO. These results suggest that NO produced in response to proinflammatory cytokines participates in the modulation of ALP activity via the activation of COX pathway. The interaction between NO and the COX pathways may play an important role in the regulation of osteoblastic functions under physiologic as well as pathologic conditions.

3T3 Cells↗
PubMed1997

Detection and characterization of hepatic tumors: value of combined helical CT hepatic arteriography and CT during arterial portography.

OBJECTIVE: The purpose of our study was to evaluate the diagnostic accuracy of combining helical CT hepatic arteriography (CTA) with helical CT during arterial portography (CTAP) for detecting and characterizing hepatic tumors. MATERIALS AND METHODS: From January 1994 to September 1995, combined helical CTA and CTAP were performed in 52 patients (38 men and 14 women, 37-83 years old [mean, 64.1 years old]) with suspected primary or metastatic hepatic tumors before they were evaluated for hepatic resection. Retrospectively, two radiologists reviewed the CTAP images alone and subsequently matched CTA and CTAP images. The radiologists recorded a confidence level on a five-point scale for their evaluation of visible perfusion abnormalities as true lesions, and diagnostic accuracy was assessed using receiver-operating-characteristic analysis. Using the data sets obtained at the interpretation sessions by the radiologists, we determined sensitivities for CTAP alone and for combined CTA and CTAP in 28 malignant hepatic tumors that were confirmed in 19 patients who underwent definitive surgery. RESULTS: CTA revealed one hepatocellular carcinoma in a patient with severe cirrhosis and six adenomatous hyperplasias in another cirrhotic patient that CTAP failed to reveal. In comparison with CTAP alone, the combination of CTA and CTAP allowed significantly more accurate detection of lesions (area under receiver-operating-characteristic curve: 0.889 for CTAP alone versus 0.954 for CTA and CTAP combined, p < .01). The combination of CTA and CTAP also significantly raised the accuracy for characterizing hepatic tumors. Sensitivities for malignant hepatic tumors revealed in the 19 patients who underwent surgery were identical: 93% (26 of 28 tumors) with CTAP alone and with CTA and CTAP combined. CONCLUSION: Although combining CTA and CTAP does not significantly increase sensitivity for detecting hepatic tumors, the combined techniques significantly raise specificity in detecting hepatic tumors and accuracy in characterizing hepatic tumors.

Carcinoma, Hepatocellular↗
PubMed1997

Detection of hepatocellular carcinoma in patients with cirrhosis: MR imaging versus angiographically assisted helical CT.

OBJECTIVE: The purpose of our study was to compare the combination of conventional spin-echo, phase-shift gradient-recalled echo (GRE), and triple-phasic dynamic GRE MR imaging with the combination of helical CT hepatic arteriography (CTA) and CT performed during arterial portography (CTAP) in the preoperative detection of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Thirty-seven patients with cirrhosis underwent MR imaging and angiographically assisted CT imaging. Paired T1- and T2-weighted spin-echo images, paired in-phase and out-of-phase GRE images, triple-phasic dynamic GRE images, the combined MR images, and the paired CTA and CTAP images were retrospectively and independently reviewed by three radiologists. Image review was done on a segment-by-segment basis. Of the 280 liver segments, 58 segments contained 79 HCCs that were 0.5-8.0 cm (mean, 2.0 cm) in diameter. The diagnostic value of each pair of images was rated by means of receiver operating characteristic curve analysis. RESULTS: The diagnostic accuracy of combined CTA and CTAP (mean area under the receiver operating characteristic curve [Az] = 0.94) was significantly better than that of spin-echo (Az = 0.86, p < .0001), phase-shift GRE (Az = 0.83, p < .0001), dynamic GRE (Az = 0.85, p < .0001), and all combined (Az = 0.91, p < .001) MR imaging. The relative sensitivity of combined CTA and CTAP (89%) was also significantly (p < .0005) better than that of the combined MR imaging (75%). CONCLUSION: Angiographically assisted helical CT imaging was superior to MR imaging combined with conventional spin-echo, phase-shift GRE, and triple-phasic dynamic GRE techniques in the detection of HCC in patients with cirrhosis. The noninvasive dedicated combined MR imaging could not obviate invasive angiographically assisted CT imaging. Combined CTA and CTAP is recommended, especially in the preoperative examination of patients with HCC.

Aged↗
PubMed1997

[A case of retained surgical sponge penetrated into the sigmoid colon].

A thread of surgical sponge was found by colonoscopy at the sigmoid colon wall in the tip of a granuloma. The patient was a 50-year-old woman who complained of diarrhea and had a history of Cesarean section and complete hysterectomy. A radiopaque thread that used to be part of the surgical sponge was demonstrated with plain pelvic X-ray films. Abdominal CT study revealed the gossypibioma including a radiopaque thread in front of the sacrum. The patient was admitted for endoscopic extraction. Upon endoscopic observation, no thread was found and the fistula had also disappeared. The surgical sponge was considered to have been spontaneously expelled from the fistula during the intervening 22-day period.

Colonoscopy↗