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K Yoshimitsu

Publications and source records attributed to K Yoshimitsu.

At least 37 records · Page 2Linked to original sources
PubMed1998

Optimal MR cholangiopancreatographic sequence and its clinical application.

PURPOSE: To determine the appropriate acquisition parameters for magnetic resonance cholangiopancreatography (MRCP) with a half-Fourier rapid acquisition with relaxation enhancement (RARE) sequence; to determine the optimal MRCP technique by comparing half-Fourier RARE, steady-state free precession (SSFP) two-dimensional (2D) fast spin-echo (SE), and three-dimensional (3D) fast SE sequences; and to clarify the usefulness and limitations of MRCP in diagnosing pancreatic abnormalities. MATERIALS AND METHODS: Half-Fourier RARE MRCP images with varying parameters were compared by using a phantom. Duct conspicuity and contrast-to-noise ratios (C/Ns) were compared for the four MRCP techniques in a phantom and healthy volunteers. The optimal MRCP technique was used to study healthy volunteers and clinical cases. Receiver operating characteristic (ROC) curves were created for data analysis. RESULTS: A 5-mm-thick section without intersection gap was appropriate for half-Fourier RARE MRCP. Only half-Fourier RARE MRCP could depict a 1-mm duct. C/N was the highest with half-Fourier RARE, followed by 3D fast SE, 2D fast SE, and SSFP sequences. ROC curve analysis revealed no interobserver differences, and the area under the curve for detection of strictures of the main pancreatic duct was as high as 0.89. CONCLUSION: Half-Fourier RARE MRCP has the highest contrast and spatial resolution among the four techniques studied and may play an important role in diagnosing pancreatic abnormalities.

Adult↗
PubMed1998

Autoimmune pancreatitis: CT and MR characteristics.

OBJECTIVE: Our goal was to elucidate the CT and MR imaging characteristics in patients with autoimmune pancreatitis, which is a reversible chronic pancreatitis with an autoimmune cause. CONCLUSION: On CT and MR imaging, a capsulelike rim, which is thought to correspond to an inflammatory process involving peripancreatic tissues, appears to be a characteristic finding of autoimmune pancreatitis. Also, diffuse pancreatic enlargement along with hypointensity on T1-weighted MR images and delayed enhancement on dynamic CT and MR studies are other features of this disorder.

Aged↗
PubMed1998

Value of MR cholangiopancreatography in evaluating choledochal cysts.

OBJECTIVE: The aim of this retrospective study was to clarify whether MR cholangiopancreatography (MRCP) is a suitable replacement for ERCP in evaluation of the choledochal cyst. MATERIALS AND METHODS: Sixteen patients (six adult and 10 pediatric) with choledochal cysts underwent MRCP using a half-Fourier acquisition single-shot turbo spin-echo sequence. Extent of the cyst, defects within the biliary tree, and presence or absence of the anomalous junction of the pancreaticobiliary duct were evaluated. Findings were compared with those of ERCP. RESULTS: MRCP better defined the proximal biliary tree than did ERCP in two patients. Defects within the biliary tree were diagnosed correctly on MRCP in eight patients; however, two defects within the distal common bile duct were missed in pediatric patients. The presence of the anomalous junction of the pancreaticobiliary duct was revealed accurately by MRCP in all adult patients but was revealed accurately in only four of the 10 pediatric patients. CONCLUSION: MRCP appears to offer diagnostic information that is equivalent to that of ERCP for assessment of choledochal cysts in adults. In pediatric patients, MRCP should not replace ERCP; however, MRCP can play an important role as a noninvasive examination and should be considered a first-choice imaging technique for evaluation of choledochal cysts.

Adult↗
PubMed1997

Small hepatocellular carcinoma on magnetic resonance imaging. Relation of signal intensity to angiographic and clinicopathologic findings.

RATIONALE AND OBJECTIVES: The authors discuss the clinicopathologic features and angiographic vascularity of various signal intensity patterns on magnetic resonance (MR) imaging of small hepatocellular carcinomas (HCCs). METHODS: Magnetic resonance images of 88 resected HCCs (< or = 3 cm) were obtained using T1- and T2-weighted spin-echo images and T1-weighted images after gadolinium (Gd)-DTPA administration. Images were compared with angiographic and histopathologic findings. RESULTS: Forty HCCs (45%) were depicted on T1-weighted images, 51 (58%) on T2-weighted images, and 41 (49%) on T1-weighted images after Gd-DTPA administration. Overall, 64 (76%) were found on at least one image. On T1-weighted images, hyperintense HCCs histologically showed fatty metamorphosis and portal tracts within the tumor. On T2-weighted images, HCC hyperintensity correlated with expansive growth, peliotic change, and hypervascularity. By contrast, HCCs that were undetected or hypointense on T2-weighted images were well differentiated with replacing growth and portal tracts. On T1-weighted images after Gd-DTPA, hyperintense HCCs had peliotic change; undetected HCCs were well differentiated and hypovascular. CONCLUSIONS: Histologic grade, vascularity, portal tracts and peliotic change correlate with MR signal intensity. For hyperintense HCCs on T1-weighted images and hypo- or isointense HCCs on T2-weighted images, treatment methods must be assigned with the consideration that HCCs may be receiving transsinusoidal and portal blood supplies.

Adult↗
PubMed1997

Anatomy and clinical importance of cholecystic venous drainage: helical CT observations during injection of contrast medium into the cholecystic artery.

OBJECTIVE: The purpose of this study was to use helical CT to elucidate the anatomy and clinical importance of cholecystic venous drainage. SUBJECTS AND METHODS: We performed helical CT of the upper abdomen during injection of contrast medium through a superselectively catheterized cholecystic artery (cholecystic artery CT) in 28 patients, all of whom were surgical candidates for suspected hepatobiliary abnormality. In nine of these patients, CT during arterial portography (CTAP) was also performed. RESULTS: Cholecystic venous blood most frequently entered peripheral portal branches of hepatic segment V (27 of 28 patients, 96%) and segment IV (26 of 28, 93%). In order of decreasing frequency, cholecystic venous blood also drained to segments I, VI, VIII, III, and VII. Cholecystic venous blood subsequently drained into the middle hepatic vein (21 of 28, 75%) or right hepatic vein (20 of 28, 71%). In two patients with adenocarcinoma involving the gallbladder associated with multiple liver metastases, cholecystic venous drainage was seen around each metastatic focus. In the nine patients in whom both cholecystic artery CT and CTAP were performed, nontumorous portal perfusion defects were attributable to cholecystic venous drainage. CONCLUSION: Recognition of cholecystic venous drainage as a possible pathway for spread of disease from the gallbladder to the liver and also as one of the causes of non-tumorous portal perfusion defects seen on CTAP is important.

Aged↗
PubMed1997

[Early HCC and adenomatous hyperplasia: evaluation of arterial and portal blood flow with CTA, CTAP, and pathologic correlation].

In order to analyze the hemodynamic properties of early hepatocellular carcinoma (HCC) and adenomatous hyperplasia (AH), three lesions (two HCCs, one AH) depicted as hypoattenuating at CTA and iso attenuating at CTAP were correlated with the histopathological findings. The number of normal hepatic arteries in the tumor was lower than in the liver. Degeneration and narrowing of the lumens were also seen microscopically. All tumors showed the replacing growth pattern and had similar numbers of the portal tracts in the tumor to the liver. The decreased number of intratumoral normal arteries is suspected to be a characteristic finding of the early stage of HCC.

Adenoma↗
PubMed1996

Wedge-shaped lesion in the liver seen on postoperative CT. Probable thromboembolic phenomenon in the portal venous system.

PURPOSE: To demonstrate CT findings of a wedge-shaped lesion (WSL) in the liver following abdominopelvic surgery and to determine the etiology and incidence of WSL. MATERIAL AND METHODS: Retrospective review of teaching files in our institution revealed 18 cases showing postoperative WSL in the liver. We also retrospectively reviewed CT images of the liver in 104 patients with a recent history of abdominopelvic surgery performed during a period of 12 months, as well as in 102 patients with no history of surgery during the same period to be used as control. Three additional patients with WSL were found in the postoperative group and none in the control group. Liver CT images from the 21 patients showing WSL, along with their clinical data and follow-up CT where available, were retrospectively analyzed. RESULTS: I.v. contrast-enhanced CT showed homogeneous higher attenuation of WSL than the surrounding liver in all cases; unenhanced CT showed low density in 5 patients, isodensity in 7 patients, and high density in 5 patients as compared with the surrounding liver. Density on unenhanced CT was significantly correlated with the presence or grade of fatty liver (p<0.01). In 5 cases CT demonstrated clots in the portal vein branch within the area of WSL and in 2 cases portal perfusion defects were observed on arterial portal CT, corresponding to the areas of WSL. Follow-up CT examinations were available on 15 patients: WSL became less prominent, or atrophic, or showed no change in 10, 2 and 3 patients respectively. Follow-up CT showed development of liver metastasis in only 3 cases. Only 2 of the 21 patients were clinically symptomatic; one had postoperative ileus and the other obstructive jaundice. CONCLUSION: Postoperative WSL may represent a thromboembolic phenomenon at the peripheral intrahepatic branch of the portal venous system during or after abdominopelvic surgery, resulting in a compensatory increase in the hepatic arterial flow that appears as wedge-shaped enhancement on CT. This is a clinically asymptomatic and uncommon phenomenon (occurring in 3% of abdominopelvic surgeries). It is important that this phenomenon is not confused with liver metastasis.

Abdominal Neoplasms↗
PubMed1995

Hepatic arterial infusion of recombinant platelet factor-4 suppresses metastases to the lungs from tumors implanted into the livers of rabbits.

BACKGROUND: This study evaluated the toxicity (Part I) and antitumor effects (Part II) associated with hepatic arterial infusion of recombinant platelet factor-4 (rPF4), an antiangiogenic protein. METHODS: Healthy rabbits (Part I) and rabbits with tumors implanted in their livers (Part II) received saline or rPF4 via hepatic arterial infusion. Three saline-receiving and four rPF4-receiving animals died 2-3 days postinfusion from gastroduodenal thromboembolism. The remaining animals were necropsied 3, 7, 10, or 14 days postinfusion. Blood analyses and hepatic angiography were performed before infusion and at the time of sacrifice. RESULTS: In Part I, focal coagulation necrosis of the hepatic parenchyma was observed in 1 of 11 rabbits that received saline and in 6 of 10 that received rPF4. In Part II, hepatic arterial infusion of rPF4 had no effect on growth of the implanted liver tumors. However, the protein significantly reduced the incidence of lung metastasis. CONCLUSIONS: Intraarterial infusion of rPF4 significantly reduced the incidence of lung metastasis. Nonheparin systemic anticoagulation may be needed during catheterization and infusion procedures to prevent thromboemboli.

Animals↗
PubMed1995

Small hepatocellular carcinomas undetected on two-phased incremental computed tomography. Angiographic and clinicopathologic findings.

RATIONALE AND OBJECTIVES: To elucidate the characteristic clinicopathologic features of hepatocellular carcinomas (HCCs) undetected on two-phased incremental computed tomography (CT). METHODS: Computed tomographic scans of 115 surgically resected small (< or = 3 cm) HCCs from 83 patients were performed 45 seconds and 6 minutes after the administration of contrast material. These scans were compared with corresponding angiographic and histopathologic findings. RESULTS: Eighty HCCs (70%) were depicted on the early images; 73 (63%) on the delayed images; and 89 (77%) using two-phased incremental CT. The small HCCs undetected on the early images but seen histologically had the following characteristics: (1) absence of a fibrous capsule, (2) well-differentiated tumor, (3) replacing growth patterns of the tumors, (4) lack of fatty metamorphosis and/or clear cell changes, (5) hypovascular on angiography. Those not seen on delayed images had the following characteristics: (1) absence of a fibrous capsule, (2) replacing growth patterns, and (3) presence of portal tracts in the tumors. CONCLUSIONS: The replacing growth pattern and the presence of portal tracts correlate with the undetectability on CT. For HCCs undetected on CT, treatment methods must be considered carefully, because the HCCs may be receiving transsinusoidal and portal blood supplies.

Adult↗
PubMed1994

Pathways of nodal metastasis from pelvic tumors: CT demonstration.

Although the normal pathways of lymphatic drainage from the pelvic organs have been well described in the anatomy literature, the pathways of nodal metastasis from individual pelvic neoplasms are not well illustrated in the imaging literature. The authors retrospectively reviewed computed tomographic scans of the abdomen and pelvis in patients with various pelvic neoplasms, including those of the ovary, testis, prostate, cervix, bladder, anorectum, and other sites, to define the pathways of nodal metastasis. In most patients, pathways of nodal metastasis correlated well with the normal lymphatic pathways described in the anatomy literature, including the superficial inguinal pathway; the anterior, lateral, hypogastric, and presacral routes of the pelvic pathway; and the paraaortic pathway. However, there also were various uncommon pathways of nodal metastasis, such as metastasis along the gonadal vessels, mesenteric and mesocolic nodes, posterior iliac crest nodes, and inferior phrenic nodes. Understanding these common and uncommon lymphatic pathways of metastasis will help radiologists detect disease spread from pelvic tumors.

Humans↗
PubMed1993

Intrahepatic splenosis mimicking a liver tumor.

A rare case of ectopic splenic tissue in the liver is presented which mimicked a liver tumor. It is considered that some splenic tissue was seeded in the liver during the splenectomy that the patient underwent 23 years ago. Computed tomography (CT), magnetic resonance imaging (MRI), and angiographic features of this lesion were almost indistinguishable from those of other liver tumors.

Choristoma↗
PubMed1993

[A quality control for the culture system using endotoxin assays in human in vitro fertilization and embryo transfer].

The purpose of this study is to investigate the effects of endotoxin on human in vitro fertilization and embryo transfers (IVF-ET) and to evaluate a quality control system for a culture medium using endotoxin assays. Before the final water purification (in an ultra-pure water system with a depyrogen filter) of the medium, the sources of water were pre-purified as follows; (I) distillation-->deionization x 2, (II) distillation-->ultra-pure water system or (III) reverse osmosis system. The limulus amebocyte lysate gelation tests (sensitivities of 0.03 and 0.25EU/ml) were used to detect endotoxin in the medium and in pre-purified water (pre-water). No pregnancies occurred in the endotoxin-positive medium (endotoxin > or = 0.03EU/ml). The endotoxin-negative medium resulted in a 33.3% pregnancy rate and 13.4% implantation rate. No statistical differences in the implantation rate were found among these methods of pre-purification (I: 12.5%, II: 13.4% and III: 20.0%). Endotoxin was detected in all the pre-water between 0.25 and 4.0EU/ml. The clinical pregnancy rate (36.6%) and the implantation rate (16.9%) in pre-water of endotoxin < 0.25EU/ml were significantly higher than those (10.5% and 5.5%) in pre-water of endotoxin > or = 0.25EU/ml (p < 0.05). We confirmed that a very low concentration of endotoxin disturbed a human embryo implantation. Endotoxin assays, not only in the media, but also in pre-water before final purification are useful as a quality control for the IVF-ET program.

Culture Media↗
PubMed1989

Heterotopic gastric mucosa of the duodenum mimicking a duodenal cancer.

Heterotopic gastric mucosa of peculiar shape and located in the duodenum bore a close resemblance to superficial ulcerating cancer. Radiographic survey showed a flexible lesion with a mucosal pattern resembling area gastrica. Endoscopy revealed its color to be indistinguishable from that of the normal duodenal mucosa. These may be characteristic features of this abnormality.

Adult↗
PubMed1989

Plasmacytoma of the pancreatic head.

Plasmacytomas of the pancreas are extremely rare. This is a report of a patient with plasmacytoma of the head of the pancreas who also had an extramedullary plasmacytoma of the epipharynx 19 months earlier. Computed tomographic (CT) scans revealed a multilobular homogeneous mass in the pancreas. Endoscopic biopsy of adjacent polypoid lesions in the duodenum allowed confirmation of the diagnosis.

Aged↗
PubMed1989

Single tuberculous stricture in the jejunum: report of 2 cases.

Intestinal tuberculosis is now considered rare. It usually involves the ileocecal region and often produces multiple ulcers in the small intestine. This is a report of 2 patients who presented with a single tuberculous stricture in the jejunum, an exceedingly rare manifestation of this disease. The stricture in each case consisted of a short girdle ulcer with irregular margins, detected by double-contrast studies of the small intestine.

Constriction, Pathologic↗
PubMed1989

Dating sonographic endometrial images in the normal ovulatory cycle.

Pelvic sonograms were obtained from 5 fertile volunteers and 150 infertile patients with normal ovulatory cycles, using real-time ultrasound. The existence of a linear cavity echo (C), thick hypoechoic layer (H) and increased echogenicity (E) were chosen as the parameters of sonographic endometrial images to be studied for dating the ovulatory cycle. In 109 serial sonograms from the fertile volunteers, H was observed from 3 days before ovulation (day -3) to ovulation day (day 0). E was observed from day +1 to day +8, and C, from day -10 to day +3. Studies on 189 sonograms from the infertile patients revealed a similar pattern for these parameters. We tested the accuracy of sonographic images of the endometrium, using sonograms from five patients who underwent hysterectomy. The measurements of endometrial thickness, in vivo, and in vitro, showed little difference. Sonographic endometrial images are considered indicative of histological changes, under the influence of estradiol and progesterone. Therefore, observation of the combined quantitative changes in C, H and E facilitates dating of the sonographic endometrial images in a normal ovulatory cycle.

Adult↗
PubMed1988

Sonographic study of the endometrial responses to ovarian hormones in patients receiving ovarian stimulation.

A total of 486 endometrial sonograms from 60 cases were reviewed to study the endometrial responses. There was a significant change in the proportion of each sonographic criterion between the pre- and post-ovulatory phases. After ovulation endometrial image showed distinct changes, and its thickness increased. These results suggest that classification of endometrial sonograms according to criteria and thickness measurements provides useful information.

Adult↗