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Biomedical subjects

Kengo Yoshimitsu

Publications and source records attributed to Kengo Yoshimitsu.

At least 19 recordsLinked to original sources
PubMed2006

Significance of mesenteric lymphadenopathy after pancreaticoduodenectomy for periampullary carcinomas: evaluation with serial MDCT studies.

OBJECTIVE: To evaluate the significance of mesenteric lymphadenopathy arising after pancreaticoduodenectomy (PD) for periampullary carcinomas. MATERIALS AND METHODS: Serial multidetector CT (MDCT) studies in 44 patients after PD for periampullary carcinomas (Group A) were retrospectively reviewed, the incidence and interval changes of mesenteric lymphadenopathy were evaluated, and comparisons were made with 21 patients who underwent PD for benign diseases (Group B). RESULTS: In Group A, mesenteric lymphadenopathy was seen in 31 of 44 (70.5%) patients. The short axis diameter of the largest lymph node ranged from 6.2 to 11.5mm (mean+/-S.D.: 8.6+/-1.4mm), and the short-axis-to-long-axis (S/L) ratio ranged from 0.46 to 0.99 (mean+/-S.D.: 0.69+/-0.12). Six of the 31 (19.4%) mesenteric lymphadenopathy cases showed interval increases in size on follow-up studies, and three cases showed new development of mesenteric lymphadenopathy: all of these nine cases had concurrent recurrence in the mesenteric root. In Group B, 11 (52.4%) had mesenteric lymphadenopathy. The short axis diameter of the largest lymph node ranged from 5.6 to 10.9mm (mean+/-S.D.: 8.0+/-1.9mm) and the S/L ratio ranged from 0.48 to 0.93 (mean+/-S.D.: 0.67+/-0.12). Differences in the incidence, short axis diameter and S/L ratio were not significant between Groups A and B (p=0.154, 0.271 and 0.654, respectively). CONCLUSION: Mesenetric lymphadenopathy after PD less likely reflects recurrence. Lymph node metastasis may be suggested only when coexisting recurrent mass is found in the proximal mesenteric root.

Adult↗
PubMed2006

Arterial steroid injection therapy can inhibit the progression of severe acute hepatic failure toward fulminant liver failure.

AIM: To utilize transcatheter arterial steroid injection therapy (TASIT) via the hepatic artery to reduce hepatic macrophage activity in patients with severe acute hepatic failure. METHODS: Thirty-four patients with severe acute hepatic failure were admitted to our hospital between June 2002 to June 2006 providing for the possibility of liver transplantation (LT). Seventeen patients were treated using traditional liver supportive procedures, and the other 17 patients additionally underwent TASIT with 1000 mg methylprednisolone per day for 3 continuous days. RESULTS: Of the 17 patients who received TASIT, 13 were cured without any complications, 2 died, and 2 underwent LT. Of the 17 patients who did not receive TASIT, 4 were self-limiting, 7 died, and 6 underwent LT. Univariate logistic analysis revealed that ascites, serum albumin, prothrombin time, platelet count, and TASIT were significant variables for predicating the prognosis. Multivariate logistic regression analysis using stepwise variable selection showed that prothrombin time, platelet count, and TASIT were independent predictive factors. CONCLUSION: TASIT might effectively prevent the progression of severe acute hepatic failure to a fatal stage of fulminant liver failure.

Adult↗
PubMed2006

Papillary renal carcinoma: diagnostic approach by chemical shift gradient-echo and echo-planar MR imaging.

PURPOSE: To elucidate whether MRI can detect fat in interstitial histiocytes and hemosiderin (Hs) deposition (both of which are histological characteristics of papillary renal carcinoma (RCpap)) within RCpap. MATERIALS AND METHODS: Preoperative MR images of nine surgically confirmed RCpap and 57 clear cell renal carcinoma (RCcc) cases were retrospectively studied. Solid components of the lesions were evaluated. For fat detection, signal reduction on opposed-phase images of chemical shift MRI (CSI) was used. For Hs detection, signal reduction on echo-planar images or in-phase images of CSI was used. The prevalence of fat and Hs detection was compared between RCpap and RCcc. RESULTS: In five of nine RCpap (54%), and 38 of 57 RCcc (67%), the presence of fat within the tumor was suggested by CSI (P = 0.71). Hs deposition within tumors was suggested by either EPI or CSI in nine of nine RCpap (100%), and 28 of 57 RCcc (51%) (P = 0.0036). Hs in RCpap was observed without or apart from necrosis or hemorrhage, whereas Hs in RCcc was located predominantly around necrosis. CONCLUSION: Detecting intratumoral Hs by EPI or CSI, particularly that unrelated to necrosis or hemorrhage, may help differentiate RCpap from RCcc.

Aged↗
PubMed2006

Small bowel perforation resulting from blunt abdominal trauma: interval change of radiological characteristics.

PURPOSE: We analyzed radiography and computed tomography (CT) findings of small bowel perforation due to blunt trauma to identify the keys to diagnosis. MATERIALS AND METHODS: Twelve patients with surgically proven small bowel perforation were retrospectively studied. All patients underwent radiography and CT, and five underwent presurgical follow-up CT. Radiological findings were evaluated and correlated to the elapsed time from the onset of the trauma retrospectively. RESULTS: Radiography demonstrated free air in only 8% (1/12) and 25% (3/12) at the initial and follow-up examinations, respectively. In contrast, the initial and follow-up CT scans detected extraluminal air in 58% (7/12) and 92% (11/12), respectively. Mesenteric fat obliteration was seen in 58% (7/12) and 75% (9/12) at initial and follow-up CT, respectively. The incidence of both extraluminal air and mesenteric fat obliteration on CT increased as time elapsed, particularly after 8 h. High-density ascites was seen in 75% at initial CT, including two patients without extraluminal air, but was observed in all but one patient at follow-up CT. CONCLUSION: The chance of detecting extraluminal air increases as time elapses. High-density ascites may be seen without extraluminal air and might be an indirect or precedent sign of small bowel perforation. Radiologists need to be familiar with these radiological features.

Abdominal Injuries↗
PubMed2006

Hepatocellular carcinoma with a prominent vascular scar in the center: MR imaging findings.

We report herein a case of hepatocellular carcinoma (HCC) with a prominent central scar. Dynamic CT and MRI studies revealed a hypervascular liver mass and a washout of contrast material in the delayed phase. The tumor center showed particular hyperintensity on T2-weighted images and delayed or prolonged enhancement. The surgical specimen revealed moderately differentiated HCC with a central scar. The central scar consisted of prominent vascular channels and loose fibrous tissue, indicative of a vascular scar. We should understand MR imaging findings of this type of central scar in the HCC.

Aged↗
PubMed2006

Usefulness of artificial neural network for differential diagnosis of hepatic masses on CT images.

RATIONALE AND OBJECTIVE: Our purpose in this study is to apply an artificial neural network (ANN) for differential diagnosis of certain hepatic masses on computed tomographic (CT) images and evaluate the effect of ANN output on radiologist diagnostic performance. MATERIALS AND METHODS: We collected 120 cases of hepatic disease. We used a single three-layer feed-forward ANN with a back-propagation algorithm. The ANN is designed to differentiate four hepatic masses (hepatocellular carcinoma, intrahepatic peripheral cholangiocarcinoma, hemangioma, and metastasis) by using nine clinical parameters and 24 radiological findings in dual-phase contrast-enhanced CT images. Thus, the ANN consisted of 33 input units and four output units. Subjective ratings for the 24 radiological findings were provided independently by two attending radiologists. All clinical cases were used for training and testing of the ANN by implementation of a round-robin technique. In the observer test, CT images of all 120 cases (30 cases for each disease) were used. CT images were viewed by seven radiologists first without and then with ANN output. Radiologist performance was evaluated by using receiver operating characteristic (ROC) analysis on a continuous rating scale. RESULTS: Averaged area under the ROC curve for ANN alone was 0.961. The diagnostic performance of seven radiologists increased from 0.888 to 0.934 (P < .02) when they used ANN output. CONCLUSION: The ANN can provide useful output as a second opinion to improve radiologist diagnostic performance in the differential diagnosis of hepatic masses seen on contrast-enhanced CT.

Aged, 80 and over↗
PubMed2006

MDCT of the gonadal veins in females with large pelvic masses: value in differentiating ovarian versus uterine origin.

OBJECTIVE: The objective of our study was to determine the usefulness of recognizing the continuity of the gonadal veins to the pelvic mass to differentiate ovarian versus uterine origin on MDCT in females with a large pelvic mass. MATERIALS AND METHODS: Two radiologists interpreted the MDCT images obtained on a monitor, using paging methods, in 86 female patients with a large pelvic mass (> 8 cm) and 40 patients without an abdominopelvic mass as control subjects. The following issues were recorded using a 5-point scale: visualization of gonadal veins and origin determination based on anatomic continuity. Receiver operating characteristic (ROC) curve analysis was performed, and the interobserver differences were checked with kappa statistics. The maximum diameters of the gonadal veins were also measured. With consensus interpretations, the sensitivity, specificity, and accuracy of ovarian origin determination were calculated. RESULTS: Gonadal veins were shown in more than 70% of the subjects in both the control group and the patients with a mass (hereafter referred to as the "mass group"). There was no significant difference in the diameter of the gonadal veins between the control and mass groups and between patients with an ovarian mass and those with a uterine mass. The values for the area under the ROC curve (A(z)) of the two observers for ovarian origin determination were 0.90 and 0.92. The kappa value was 0.48. The sensitivity, specificity, and accuracy were 83.3%, 87.5%, and 84.9%, respectively. CONCLUSION: Gonadal veins can be shown on MDCT with high consistency; MDCT provides useful information for determining the origin of relatively large pelvic tumors arising in females.

Adult↗
PubMed2006

Accessory left gastric artery from left hepatic artery shown on MDCT and conventional angiography: correlation with CT hepatic arteriography.

OBJECTIVE: The objective of our study was to evaluate the diagnostic accuracy of MDCT and conventional angiography in the detection of an accessory left gastric artery using CT hepatic arteriography as the standard of reference. MATERIALS AND METHODS: The study group consisted of 118 patients who underwent MDCT with a triple-phase liver protocol with a slice thickness of 5 mm, conventional angiography, and CT hepatic arteriography. The early-phase images of MDCT and conventional angiography were retrospectively reviewed. The presence or absence of an accessory left gastric artery was evaluated using CT hepatic arteriography as the standard of reference. The sensitivity, specificity, and accuracy of MDCT and conventional angiography were calculated. RESULTS: CT hepatic arteriography revealed an accessory left gastric artery in 25 (21.2%) of 118 cases, including 15 proximal- and 10 distal-type accessory left gastric arteries. On MDCT, there were seven false-negative cases and one false-positive case. Six of the seven false-negative cases were a proximal-type accessory left gastric artery, and nine of 10 distal-type accessory left gastric arteries were correctly diagnosed using MDCT. The sensitivity, specificity, and accuracy of MDCT were 72.0%, 98.9%, and 93.2%, respectively. On conventional angiography, there were three false-negative and two false-positive cases, none of whom underwent selective left hepatic arteriography. Two of the three false-negative cases were the distal-type accessory left gastric artery, but eight of the 10 distal-type accessory left gastric arteries were correctly diagnosed. The sensitivity, specificity, and accuracy of conventional angiography were 88.0%, 97.8%, and 95.8%, respectively. CONCLUSION: Approximately 70% of accessory left gastric arteries can be diagnosed at the early phase of MDCT even with a slice thickness of 5 mm.

Adult↗
PubMed2005

Delayed-phase dynamic CT enhancement as a prognostic factor for mass-forming intrahepatic cholangiocarcinoma.

PURPOSE: To retrospectively determine whether the degree of contrast material enhancement at delayed-phase dynamic computed tomography (CT) for intrahepatic cholangiocarcinoma (ICC) is related to the patient's prognosis after surgery. MATERIALS AND METHODS: Neither institutional review board approval nor informed consent was required for this retrospective evaluation. Thirty-two patients (22 men, 10 women; mean age, 60.8 years; range, 33-80 years) with mass-forming ICC underwent dynamic CT. Delayed CT images obtained 4-6 minutes after the injection of contrast material were evaluated by two radiologists. Patients were classified in consensus into one of two groups: Group 1 included those in whom more than two-thirds of the tumor showed enhancement on delayed-phase scans. Group 2 included those in whom less than two-thirds of the tumor showed enhancement on delayed-phase scans. The imaging findings were correlated with pathologic findings. Survival curves were drawn by using the Kaplan-Meier method, and the differences between the groups were compared with the log-rank test. Multivariate analysis was performed to clarify prognostic factors. RESULTS: There were 13 patients in group 1 and 19 in group 2. The degree of enhancement on the delayed-phase images showed statistically significant correlation with the amount of fibrous stroma (P < .001) and the frequency of perineural invasion (P < .01). The survival rate in group 1 was significantly lower than that in group 2 (P = .016). Multivariate analysis revealed that enhancement of more than two-thirds of the ICC was a significant and independent prognostic factor. CONCLUSION: The degree of enhancement on delayed-phase CT scans is a useful indicator for prediction of the prognosis of patients with mass-forming ICC.

Adult↗
PubMed2005

The incidence of hepatic pseudolesions caused by focal rib compression as seen on multidetector row CT in patients of different hepatic function.

OBJECTIVE: To determine whether the incidence of pseudolesions of the liver caused by rib compression is correlated with liver function. MATERIALS AND METHODS: Multidetector row CT images of 150 consecutive cases were evaluated for the presence of pseudolesions caused by rib compression. Liver function was categorized into two groups mainly using the Child-Pugh classification: Group I-normal liver function and Grade A; Group II-Grades B and C. The number of focal deformities of the liver caused by rib compression was also counted. The incidence of pseudolesions based on number of patients or focal deformities of liver parenchyma by rib compression were compared between the two groups. RESULTS: There were 108 and 42 patients in Groups I and II, respectively. 169 and 41 focal deformities of the liver caused by rib compression were found in Groups I and II, respectively. Patient-based and deformity-based incidences of pseudolesions were 10.7% (16/150) and 7.6% (16/210), respectively. All pseudolesions were seen in patients of Group I. Both patient-based and deformity-based incidences of pseudolesions were significantly higher in Group I as compared with those in Group II. CONCLUSION: Pseudolesions of the liver caused by focal rib compression may be seen more frequently in patients with preserved liver function than in those with impaired function.

Adult↗
PubMed2005

Short-term intensive treatment for donors with hepatic steatosis in living-donor liver transplantation.

BACKGROUND: The use of steatotic livers is associated with increased primary nonfunction in liver transplantation. To reduce the risk of liver injury, we applied a short-term combination therapy of diet, exercise and drugs for 11 living-donor liver transplantation (LDLT) candidates with steatosis. METHODS: Subjects were treated with a protein-rich (1000 kcal/day) diet, exercise (600 kcal/day), and bezafibrate (400 mg/day) for 2-8 weeks. RESULTS: The treatment significantly improved macrovesicular steatosis (30+/-4% vs. 12+/-2% [mean +/- SEM], P = 0.0028). Body weight and BMI were significantly reduced (73.7 +/- 3.2 kg vs. 66.9 +/- 2.9 kg, P = 0.0033, 26.4 +/- 0.7 kg/m vs. 24.1 +/- 0.8 kg/m, P = 0.0033). The treatment completely normalized liver function tests and lipid metabolism. Seven treated liver grafts (left lobe) were transplanted to the recipients. We compared transplanted graft function and resected liver function of donors using parameters such as peak total bilirubin, prothrombin time at postoperative day 3, and peak alanine aminotransferase between treated liver (n = 7) and donor liver without hepatic steotosis (n = 37). The transplanted grafts showed good liver functions, and there was no difference between them with respect to functional parameters. The treated donors also showed good liver functions, and no significant differences in functional parameters. CONCLUSIONS: The results of this study indicate that our short-term treatment effectively reduced steatosis and contributed to safer LDLT. Our findings also suggest that even severely steatotic livers can be used for LDLT grafting subsequent to our short-term treatment regimen.

Adult↗
PubMed2005

Diffusion-weighted echo-planar MR imaging and ADC mapping in the differential diagnosis of ovarian cystic masses: usefulness of detecting keratinoid substances in mature cystic teratomas.

PURPOSE: To elucidate whether apparent diffusion coefficient (ADC) values calculated from echo-planar diffusion-weighted MR imaging (EPDWI) are useful in the differential diagnosis of ovarian cystic masses. MATERIALS AND METHODS: EPDWI was performed in 131 patients with ovarian cystic masses (54 mature cystic teratomas, 35 endometrial cysts, four other benign cysts, 14 benign neoplasms, and 24 malignant neoplasms). The areas of the highest signal intensity on EPDWI (b = 1000 seconds/mm(2)) and the lowest ADC values within the cystic component were evaluated. RESULTS: On qualitative and quantitative analyses, mature cystic teratomas tended to show higher signal intensity and had areas of lower ADC values than endometrial cysts and other benign and malignant neoplasms (P < .005). In vitro scanning of the cystic contents of mature cystic teratomas confirmed that high signal on DWI or low ADC value was attributable to the keratinoid substance within the tumors. The difference in ADC between malignant and benign lesions were significant when mature cystic teratomas and endometrial cysts were included, but was not significant when they were excluded. CONCLUSION: The ADC value may add useful information to the differential diagnosis of ovarian cystic masses in limited populations, such as those with mature cystic teratomas with a small amount of fat.

Adult↗
PubMed2005

Validity of preoperative volumetric analysis of congestion volume in living donor liver transplantation using three-dimensional computed tomography.

Reconstruction of middle hepatic vein (MHV) tributaries is controversial in right-lobe living donor liver transplantation (LDLT). This study aimed to evaluate the appropriateness of reconstructing MHV tributaries by volumetry using 3-dimensional computed tomography (3D-CT). Between November 2003 and January 2005, 42 donor livers (right-lobe graft, n = 25; left-lobe graft, n = 17) were evaluated using this software. The total congestion volume (CV) associated with the MHV tributaries and the inferior right hepatic vein (IRHV), and graft volume (GV) were calculated. In recipients with right-lobe grafts, CV/(right liver volume [RLV]) and (GV - CV)/(standard liver volume [SLV]) were compared between 2 groups: with reconstruction (n = 16) and without reconstruction (n = 9). To evaluate the influence of CV on the remnant right lobe in donors, total bilirubin was compared between 2 groups: high CV (CV > 20%, n = 13) or low CV (CV < or = 20%, n = 4). The mean CV/RLV ratio was 32.3 +/- 17.1% (V5, 15.2 +/- 9.9%; V8, 9.2 +/- 4.1%; and IRHV, 8.5 +/- 11.4%) and the maximum ratio was as high as 80.8%. The mean (GV - CV)/SLV ratio before reconstruction in patients with or without reconstruction resulted in 33.5 +/- 12.8% and 55.4 +/- 12.9%, respectively (P < 0.01). In donors, total bilirubin was significantly high in the high CV group on postoperative day 1 compared with the low CV group (P < 0.05). In conclusion, calculation of CV using 3D-CT software proved to be very useful. We concluded that this evaluation should be an integral part of procedure planning, especially for right-lobe LDLT.

Adult↗
PubMed2005

Multifocal nodular lymphoid hyperplasia of the lung.

Nodular lymphoid hyperplasia (NLH) is one of the pulmonary lymphoproliferative disorders, and was initially described as pseudolymphoma. However, reports focusing on CT findings of NLH of the lung have been rare. We report a case of a pulmonary NLH in a 49-year-old woman who showed multiple pulmonary nodules on HRCT and was misdiagnosed preoperatively with adenocarcinoma on the basis of transthoracic cytology. A final diagnosis of NLH was made on postoperative histologic examination.

Female↗
PubMed2005

Percutaneous femoral catheter placement for long-term chemotherapy infusions: preliminary technical results.

OBJECTIVE: The purpose of our study was to evaluate the feasibility and usefulness of using a port-catheter system equipped with a W-spiral catheter for hepatic chemotherapy; this novel catheter does not require fixation by pericatheter embolization and can be safely withdrawn when not needed. SUBJECTS AND METHODS: Sixty-one patients (40 men and 2l women; mean age, 59 years) with advanced liver cancers (primary hepatic or biliary cancer [n = 31] and metastatic liver cancer [n = 30]) underwent percutaneous port-catheter placement with the tip of W-spiral catheter inserted into the right gastroepiploic artery and the side-hole opened at the common hepatic artery after embolization of the right gastric artery, pancreaticoduodenal arteries, or aberrant hepatic arteries. Pericatheter embolization for preventing catheter dislodgement was not performed. The technical success of port-catheter placement, clinical patency of the port-catheter system, and technical success of port-catheter removal were evaluated. RESULTS: Percutaneous port-catheter placement using this method was successfully performed in 59 (97%) of 61 patients. Subsequently, chemotherapy was successfully performed through the port in 57 (93%) of 61 patients. Complications during and after the procedure were observed in two (3%) of 61 patients and 12 (20.7%) of 58 patients. Hepatic artery thrombosis occurred in two (3.4%) of 58 patients. The port-catheter removal and the catheter replacement were performed in eight and four patients, respectively, who wanted the procedure. It was completed successfully without any complications. CONCLUSION: This method of implantation of a port-catheter system appeared to offer clinical advantages of safe catheter removal, femoral artery access, and an acceptable complication rate.

Adult↗