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Kan Takeda

Publications and source records attributed to Kan Takeda.

At least 37 records · Page 2Linked to original sources

Usefulness of the apparent diffusion coefficient in line scan diffusion-weighted imaging for distinguishing between squamous cell carcinomas and malignant lymphomas of the head and neck.

BACKGROUND AND PURPOSE: Squamous cell carcinoma (SCC) and lymphoma are common malignant tumors of the head and neck. The purpose of this study was to determine whether the apparent diffusion coefficient (ADC) in line scan diffusion-weighted imaging (LSDWI) is useful for distinguishing between SCC and lymphoma of the head and neck. METHODS: LSDWI was prospectively performed in 39 patients with SCC and in 14 patients with lymphoma. Images were obtained with a diffusion-weighted factor (b factor) of 5 and 1000 s/mm(2), and ADC maps were generated. ADC values were measured for the two types of tumor. RESULTS: Mean ADC values were 0.96 +/- 0.11 x 10(-3) mm(2)/s for SCC and 0.65 +/- 0.09 x 10(-3) mm(2)/s for lymphoma; the difference was significant (P < .001). All but one of the patients with lymphoma had ADC values lower than the lowest ADC (0.76 x 10(-3) mm(2)/s) in patients with SCC. When an ADC of 0.76 x 10(-3) mm(2)/s was used to distinguish between SCC and lymphoma, accuracy was 98% (52 of 53 lesions). CONCLUSION: ADC values appear to be useful for distinguishing between SCC and lymphoma in the head and neck.

Adolescent↗

Improved survival using multi-modality therapy in patients with lung metastases from colorectal cancer: a preliminary study.

This retrospective study was conducted to assess the safety, efficacy, and long-term results of multi-modality therapy including radio-frequency thermal ablation (RFA) and radiotherapy as an additional cytoreductive method for eliciting the marked effects of chemotherapy in treating unresectable lung metastases from colorectal cancer. Total of 21 patients with lung metastasis from colorectal cancer were included. They were treated with modified pharmacokinetic modulating chemotherapy (PMC). Eleven were also treated with RFA and/or radiotherapy (multi-modality group), and 10 were treated with chemotherapy alone (chemotherapy group). Characteristics and survival of patients in the multi-modality group were compared with those of the chemotherapy group. The median survival of all patients was 38.6 months after the initial PMC. The cumulative 3-year survival rate of patients in the multi-modality group was 87.5% compared with 33.3% in the chemotherapy group (p=0.0041). The course of multi-modality therapy was uneventful except for pneumothorax in those who received RFA. Although pneumothorax developed in 4 of 11 patients (36.4%) treated with RFA, all were able to receive chemotherapy within 2 weeks after RFA. In conclusion, multi-modality therapy combined with modified PMC, radiation and RFA is a feasible choice of treatment associated with reasonable morbidity and mortality in patients with inoperable lung metastases from colorectal cancer.

Adult↗

Single photon emission computed tomography and statistical parametric mapping analysis in cirrhotic patients with and without minimal hepatic encephalopathy.

OBJECTIVE: The early diagnosis and treatment of cognitive impairment in cirrhotic patients is needed to improve the patients' daily living. In this study, alterations of regional cerebral blood flow (rCBF) were evaluated in cirrhotic patients using statistical parametric mapping (SPM). The relationships between rCBF and neuropsychological test, severity of disease and biochemical data were also assessed. METHODS: 99mTc-ethyl cysteinate dimer single photon emission computed tomography was performed in 20 patients with non-alcoholic liver cirrhosis without overt hepatic encephalopathy (HE) and in 20 age-matched healthy subjects. Neuropsychological tests were performed in 16 patients; of these 7 had minimal HE. Regional CBF images were also analyzed in these groups using SPM. RESULTS: On SPM analysis, cirrhotic patients showed regions of significant hypoperfusion in the superior and middle frontal gyri, and inferior parietal lobules compared with the control group. These areas included parts of the premotor and parietal associated areas of the cortex. Among the cirrhotic patients, those with minimal HE had regions of significant hypoperfusion in the cingulate gyri bilaterally as compared with those without minimal HE. CONCLUSIONS: Abnormal function in the above regions may account for the relatively selective neuropsychological deficits in the cognitive status of patients with cirrhosis. These findings may be important in the identification and management of cirrhotic patients with minimal HE.

Aged↗

Stent-graft placement combined with percutaneous fenestration for the treatment of aortic dissection in a patient at risk of developing renal ischemia.

A 51-year-old man, suffering from an aortic dissection with the entry tear in the descending thoracic aorta, underwent replacement of the ascending aorta and aortic arch with resection of the entry tear. Although the false lumen of the descending thoracic aorta was thrombosed after surgery, redissection developed in the descending aorta 2 months later. Percutaneous fenestration was performed before stent-grafting because it was judged that there was a significant risk of left renal ischemia. Entry closure with a stent-graft was performed successfully and no renal ischemia developed. The patient is doing well at 1 year after the procedure.

Anastomosis, Surgical↗

Transcatheter hepatic arterial chemoembolization for hepatocellular carcinoma invading the portal veins: therapeutic effects and prognostic factors.

PURPOSE: This retrospective study was undertaken to evaluate the therapeutic effects of transcatheter hepatic arterial chemoembolization on hepatocellular carcinoma (HCC) invading the portal veins and to identify prognostic factors. MATERIALS AND METHODS: Sixty-one patients underwent chemoembolization. The HCC had invaded the main portal vein in 23 patients, a first-order branch in 25 patients and a second-order branch in 13 patients. The hepatic arteries feeding the tumors were embolized with gelatin sponge after a mixture of iodized oil and anticancer drugs was injected via these vessels. Tumor response was evaluated by measuring tumor sizes on CT images. A reduction in maximum diameter of 25% or more was considered to indicate response to chemoembolization. Significant prognostic factors were identified by univariate and multivariate analyses. RESULTS: Tumor size was reduced by 25% or more in 26 patients (43%). The 1-, 3- and 5-year survival rates were 42, 11 and 3%, respectively, with mean survival of 15 months in all patients. In the univariate analysis, the following six variables were significantly associated with prognosis: (i) tumor response; (ii) ascites; (iii) accumulation of iodized oil in tumor thrombi; (iv) in main tumors; (v) Okuda classification; and (vi) tumor size. In the multivariate analysis, the first three of these factors showed significantly independent values for patient prognosis. CONCLUSION: Chemoembolization appears to be an effective treatment for HCCs invading the portal venous system. The prognostic factors identified here are expected to be helpful in classifying patients with HCCs invading the portal veins and should serve as useful guidelines for chemoembolization in clinical practice.

Adult↗

Thallium-201 SPECT and low-dose dobutamine stress cine MRI for predicting functional recovery of regional myocardial contraction in patients with myocardial infarction.

OBJECTIVES: The purpose of this study was to compare the diagnostic performances of Tl-201 single photon emission computed tomography (SPECT) and dobutamine stress cine magnetic resonance imaging (MRI) for predicting functional recovery of regional myocardial contraction in patients after myocardial infarction. METHODS: Twenty patients underwent Tl-201 SPECT and MRI 3-4 weeks after onset of myocardial infarction. Cine MR images were acquired in the resting state and during dobutamine stress. Tl-201 uptake and systolic wall thickening (SWT) on cine MRI were analyzed on short-axis images by using a 14-segment model. Follow-up cine MR images were obtained 187.1+/-33.5 days after onset. RESULTS: The averaged Tl-201 uptake in 54 segments with impaired SWT was 47%+/-20%, being significantly lower than that in 226 segments with preserved SWT (75%+/-18%; p<0.0001). The sensitivity, specificity, and accuracy of dobutamine MRI and Tl-201 SPECT for predicting preserved SWT after 6 months were 89% vs. 80%, not significant (NS); 89% vs. 72%, p<0.01; and 89% vs. 79%, NS, respectively. In the anterior wall and apex, the sensitivity and specificity of SPECT were not significantly different from those of MRI. In the inferior wall and posterolateral wall, however, the specificity of SPECT was substantially lower than that of MRI (53% vs. 88%, p<0.001), resulting in significantly lower accuracy (75% vs. 90%, p<0.01). CONCLUSIONS: Both SPECT and dobutamine MRI showed excellent sensitivity for predicting myocardial viability in all left ventricular segments. Decreased specificity of SPECT in the inferior and posterolateral segments resulted in lower overall specificity in comparison with dobutamine MRI.

Adult↗

Endovascular stent-graft treatment for thoracic aortic aneurysms: short- to midterm results.

PURPOSE: To evaluate short- and midterm results of the endovascular repair of thoracic aortic aneurysm (TAA) with the use of custom-made stent-grafts. MATERIALS AND METHODS: Between May 1997 and May 2003, 40 patients with TAA (26 degenerative/atherosclerotic, seven dissection-related, three traumatic, two mycotic, one anastomotic, and one penetrating ulcer) underwent endovascular stent-graft placement. The mean age of the patients (29 male and 11 female) was 67.2 years. Twenty-four of the 40 patients (60%) were judged not to be good candidates for conventional open repair. Stent-graft placement was performed in the angiography suite with general anesthesia and transient cardiac arrest or induced hypotension. Custom-made stent-grafts were used in all patients. Four of the 40 patients (10%) underwent preliminary extra-anatomic bypass surgery to provide a sufficiently long landing zone. The mean follow-up period was 16.7 months (range, 1-65 months). RESULTS: The technical success rate was 97.5% and the early mortality rate was 2.5% (one out of 40 patients). There were four late deaths (two procedure-related). Survival rates were 84.2%+/-6.6% at 1 year and 84.2%+/-6.6% at 2 years. Survival rates were not significantly different between surgical candidates and non-surgical candidates (P =.423). Intraprocedural complications included access artery complications in nine patients and bleeding in three patients. Postoperative complications included early aneurysmal expansion in one patient, pneumonia in one patient, wound infection in one patient, stroke in three patients, paraplegia in one patient, respiratory insufficiency in two patients, aortoesophageal fistula in one patient, and late aneurysmal expansion in three patients. The rates of freedom from first additional intervention were 91.0%+/-6.7% at 1 year and 74.5%+/-11.9% at 2 years. The rates of freedom from second additional intervention was 100% at 2 years. The rates of freedom from treatment failure were 84.7%+/-7.6% at 1 year and 69.3%+/-11.6% at 2 years. CONCLUSION: Endovascular repair of TAA with a custom-made stent-graft is a safe and effective alternative to open repair and continues to play an important role. However, careful follow-up is mandatory to manage complications.

Adolescent↗

Percutaneous radiofrequency ablation of lung neoplasms: initial therapeutic response.

PURPOSE: To evaluate the feasibility, safety, and initial therapeutic effect of radiofrequency (RF) ablation in the treatment of unresectable malignant lung tumors. MATERIALS AND METHODS: Fifty-four lung neoplasms in 31 patients were treated with RF ablation. Thirteen tumors were primary lung cancers and 41 were pulmonary metastases. Tumor sizes ranged from 0.7 to 6.0 cm, with a mean size of 2.7 +/- 1.3 cm. After the RF electrode was placed in the tumor with computed tomographic (CT) fluoroscopic guidance, RF energy was applied. Initial therapeutic response was evaluated by (18) F fluorodeoxyglucose positron emission tomography (FDG-PET) and contrast-enhanced CT. The disappearance of FDG uptake on PET images and tumor enhancement on CT images were considered to indicate complete tumor necrosis. Complete necrosis rates were evaluated according to tumor size and type (primary or secondary lung neoplasm). RESULTS: RF ablation was technically successful in all lesions. Complete necrosis was achieved in 32 of the 54 tumors (59%) after initial RF session. There was a significant difference in the rate of complete tumor necrosis between tumors 3 cm or less and tumors larger than 3 cm (69% vs. 39%; P <.05). Tumor type did not influence complete necrosis rates. Lung abscesses developed in two patients with large tumors. CONCLUSION: Lung RF ablation is a feasible, relatively safe, and promising treatment for unresectable lung neoplasms. Tumor size is an important factor in achieving complete tumor necrosis.

Aged↗

Hepatic arterial infusion chemotherapy with use of an implanted port system in patients with advanced hepatocellular carcinoma: prognostic factors.

PURPOSE: This study was retrospectively undertaken to identify prognostic factors in patients with advanced hepatocellular carcinoma (HCC) treated by hepatic arterial infusion chemotherapy with a percutaneously implantable port system inserted. MATERIALS AND METHODS: Eighty-eight patients underwent arterial infusion chemotherapy for portal venous invasion (n = 39), severe liver dysfunction (n = 6), or tumor regrowth after chemoembolization, percutaneous ethanol injection therapy, and surgery (n = 77). Twenty-five variables representing patients' characteristics, previous treatments, tumor characteristics, liver profiles, various staging systems, and therapeutic effect were analyzed with univariate and multivariate analyses. RESULTS: The 1- and 3-year survival rates were 55% and 24%, respectively, with a mean survival period of 19.5 months +/- 1.9 in all patients. Cancer of the Liver Italian Program (CLIP) score, Okuda stage, therapeutic effect, tumor extension, alkaline phosphatase and aspartate aminotransferase levels, ascites, and portal venous invasion were identified as significant prognostic factors by univariate analysis. Multivariate analysis identified CLIP score, Okuda stage, and therapeutic effect as significant independent prognostic factors. CONCLUSION: Although our results should be confirmed in future prospective studies, the prognostic factors identified in the present study should prove helpful in classifying patients with advanced HCC who are treated by arterial infusion chemotherapy and should serve as useful guidelines on arterial infusion chemotherapy in clinical practice.

Adult↗

Radiofrequency ablation combined with bone cement injection for the treatment of bone malignancies.

PURPOSE: To evaluate the feasibility, safety, and effectiveness of combined treatment with radiofrequency (RF) ablation followed by bone cement injection in patients with malignant bone neoplasms. MATERIALS AND METHODS: Seventeen patients with 23 bone tumors were treated. The tumors, measuring 1.2-15 cm (mean, 4.9 +/- 3.5 cm), were located in the spine (n = 17), iliac bone (n = 3), sacrum (n = 2), and ischial bone (n = 1). All procedures were performed with computed tomographic (CT) fluoroscopic guidance. An electrode with an internally cooled tip was placed in the bone tumor through a biopsy needle and RF energy was applied, followed by cement injection. Pain relief was evaluated with use of the visual analogue scale score (VAS score). Local therapeutic effects were evaluated by contrast-enhanced MR imaging. Lack of tumor enhancement was considered to indicate necrosis. RESULTS: The procedures were technically successful in all patients except for one patient with an osteoblastic ischial lesion (22 of 23 patients; 96%). Pain was relieved within 1 week in all 13 patients who reported pain (13 of 13 patients; 100%), with a significant decrease in the VAS score from 8.4 to 1.1 (P <.001). Tumor necrosis was observed in 71% +/- 24% of the tumor volume (range, 14%-100%). Neural damage occurred in four patients in whom the tumor had invaded the posterior cortex of the vertebral body and pedicle. CONCLUSION: The combined therapy described here is both feasible and useful for the treatment of malignant bone neoplasms. The safety of the procedure depends on the tumor location. When the tumor is adjacent to the spinal cord, there is a risk of nerve injury.

Bone Cements↗

Lung radiofrequency ablation with and without bronchial occlusion: experimental study in porcine lungs.

PURPOSE: This study was undertaken to compare the thermal lesion volumes in normal pig lungs when radiofrequency (RF) ablation is performed with and without airway occlusion. MATERIALS AND METHODS: RF ablation was performed in six pigs. A straight 17-gauge internally cooled-tip electrode with a 2-cm exposed tip was inserted into the center of the lower lobe of the lung under biplane fluoroscopic guidance. In each animal, RF ablation was performed for 12 minutes with balloon occlusion of the main bronchus in one lung and without balloon occlusion in the contralateral lung. The tissue temperature around the electrode tip was measured immediately after RF application. The volumes of the thermal lesions were compared by histologic examination of the groups of lungs ablated with and without airway occlusion. RESULTS: Tissue temperature was significantly higher in the bronchial occlusion group than in the group with normal ventilation (51 degrees C +/- 7 vs. 44 degrees C +/- 2; P < .05). RF ablation with bronchial occlusion resulted in the creation of a significantly greater thermal lesion volume compared with RF ablation with normal ventilation (6,535 mm(3) +/- 1,114 vs 3,368 mm(3) +/- 676; P < .03). CONCLUSION: Prevention of ventilation in the normal swine lung via bronchial balloon occlusion during RF ablation increases the thermal ablation lesion volume, suggesting that active ventilation is a significant cause of in vivo heat loss.

Airway Obstruction↗

Intrahepatic hepatic vein stenosis after living-related liver transplantation treated by insertion of an expandable metallic stent.

Although the incidence of stenosis and obstruction of the hepatic venous anastomosis after right hepatic living-related liver transplantation (LRLT) has been found to be higher than after orthotopic liver transplantation (OLT), to the best of our knowledge, intrahepatic stenosis of the venous trunk in the early period after right hepatic LRLT has never been reported in the literature. A 53-year-old man who underwent right hepatic LRLT, postoperatively, developed liver dysfunction and an increasing amount of ascites, and a Doppler sonogram showed a flat waveform and low-flow velocity in the hepatic vein. Based on these findings an outflow block was suspected, and a hepatic venogram and manometry revealed intrahepatic stenosis of a tortuous hepatic venous trunk and a pressure gradient of 14 mmHg at the site of the stenosis. We inserted an expandable metallic stent (EMS) at the site of intrahepatic venous stenosis, and its insertion was followed by a decrease in pressure gradient. Liver function recovered, and the volume of ascitic fluid decreased after placement of the EMS. The results of an analysis of the venogram and CT volumetric data suggested that the pathogenesis of the stenosis was twisting of the venous trunk during hypertrophy of the liver parenchyma.

Ascitic Fluid↗

Contrast-enhanced high-resolution MRI of invasive breast cancer: correlation with histopathologic subtypes.

OBJECTIVE: We sought to determine whether contrast-enhanced MRI could aid in the identification of the histopathologic subtypes of invasive ductal carcinoma. MATERIALS AND METHODS: We evaluated the contrast-enhanced MR images obtained in 62 women with invasive ductal carcinoma of no special type. The presence or absence of three distinct MRI findings-linear enhancement, a serrated border, and delayed rim enhancement-was evaluated. Classification and regression tree analyses were performed to construct the most efficient algorithm for predicting histopathologic subtype on the basis of dynamic MRI features. RESULTS: Histopathologic subtypes of the invasive ductal carcinomas were scirrhous carcinoma in 22 patients, solid tubular carcinoma in 14, and papillotubular carcinoma in 26. A lesion with a serrated border was observed in 28 (45.2%) of the 62 patients. Delayed rim enhancement was seen in 23 (37.1%) and linear enhancement in 20 (32.3%). Scirrhous carcinomas were closely associated with a serrated border (20/22 or 90.9%, p < 0.0001). Delayed rim enhancement was frequently observed in solid tubular carcinomas (12/14 or 85.7%, p < 0.0001) but was not typically seen in scirrhous carcinomas (1/22 or 4.5%, p < 0.0001). Linear enhancement showed relatively high prevalence in papillotubular carcinomas (13/26 or 50%) and low prevalence in solid tubular carcinomas (1/22 or 7%, p < 0.02). Histopathologic subtypes of invasive breast carcinoma of no special type could be correctly identified in 47 (75.8%) of 62 lesions using the diagnostic algorithm generated by the classification and regression tree analyses. CONCLUSION: MRI features showed a close relationship with histopathologic subtypes of invasive ductal carcinoma of no special type. Contrast-enhanced MRI can be a noninvasive diagnostic tool for histopathologic subtypes of invasive breast cancer.

Adult↗

Combination therapy with radiofrequency ablation and transcatheter chemoembolization for the treatment of hepatocellular carcinoma: Short-term recurrences and survival.

To evaluate short-term clinical results of radiofrequency (RF) ablation combined with transcatheter chemoembolization for the treatment of hepatocellular carcinoma (HCC) and to identify factors having influence on early intrahepatic recurrence. Sixty-four patients with 92 HCC lesions underwent RF ablation within 2 weeks after chemoembolization. The maximum tumor size was small (</=3 cm) in 36 patients, intermediate (3.1-5 cm) in 22 patients, and large (5.1-8.5 cm) in 6 patients. Tumors were solitary in 42 patients and multiple (2 or 3) in 22 patients. Factors affecting intrahepatic recurrence were evaluated by univariate and multivariate analyses. Intrahepatic recurrences were found in 13 patients (20%, 13/64) during the mean follow-up period of 18 months. Recurrences were found in the untreated liver in 11 patients and in both untreated liver and treated lesion in 2 patients. The cumulative intrahepatic recurrence rates were 15% at 1 year and 43% at 2 years. In the univariate analysis, multiple tumor burden and large tumor size (>5 cm) were significantly linked with higher probability of early intrahepatic recurrence. In the multivariate analysis, tumor number was the only independent factor having significant impact on early intrahepatic recurrence. The estimated 1- and 2-year survival rates were 100% and 93%, respectively. This combined therapy showed good early therapeutic effects on treated lesions and survival. Tumor number and maximum tumor size are important factors for early intrahepatic recurrence.

Aged↗

Diffuse leptomeningeal hyperintensity on fluid-attenuated inversion recovery MR images in neurocutaneous melanosis.

Neurocutaneous melanosis (NCM) is a rare neuroectodermal dysplasia characterized by large or multiple cutaneous congenital pigmented nevi and benign or malignant melanocytic tumors of the leptomeninges. Although the MR manifestations of this disease have been reported in a small series of cases, the usefulness of fluid-attenuated inversion recovery (FLAIR) MR findings has not been documented. We present a case of NCM that showed diffuse leptomeningeal hyperintensity on FLAIR images. This FLAIR finding may be a clue to the detection of leptomeningeal abnormalities in NCM.

Abnormalities, Multiple↗

[Simultaneous spatial resolution correction in SPECT reconstruction using OS-EM algorithm].

Single photon emission computed tomography (SPECT) is widely used for Nuclear Medicine. The low spatial resolution is mainly due to the limited collimator resolution. We have developed ordered subsets-expectation maximization (OS-EM) algorithm incorporating three dimensional spatial resolution correction (3D-SRC;horizontal and vertical direction) for distance-dependent blurring. In this paper we evaluate the fundamental properties of OS-EM algorithm including distance-dependent resolution correction using some phantoms (cubic phantom, cardiac and brain phantoms) and 12 patients performed 99mTc-tetrofosmin myocardial SPECT. In cubic phantom, the resolution in transaxial, coronal and sagital images are significantly improved by 3D-SRC. In short axial images of cardiac phantom, 3D-SRC shows more excellent images than no correction. In brain phantom, the blurring at the edge of the brain structure is improved by using OS-EM algorithm with 3D-SRC. In patients, the resolution in transaxial and short axial images is significant improved. These results suggest that this method improves the resolution in SPECT images and 3D-SRC is especially available in SPECT images of other axes in addition to transaxis. This method has advantage that both reconstruction and resolution correction are simultaneously performed. In the near future, we think that OS-EM algorithm incorporating attenuation, scatter and resolution correction will be used for quantitative SPECT images.

Algorithms↗

Noninfarcted myocardium: correlation between dynamic first-pass contrast-enhanced myocardial MR imaging and quantitative coronary angiography.

PURPOSE: To determine the accuracy of first-pass contrast material-enhanced stress myocardial magnetic resonance (MR) imaging for depiction of myocardial ischemia in patients without myocardial infarction. MATERIALS AND METHODS: First-pass contrast-enhanced MR images of the entire left ventricle were acquired in 104 patients at rest and during dipyridamole-induced stress by using an interleaved notched saturation technique. Coronary angiography was performed in all patients, and stress perfusion single photon emission computed tomography (SPECT) was performed in 69 patients. Receiver operating characteristic curve analysis was performed to compare the diagnostic accuracies of first-pass contrast-enhanced stress MR imaging and stress SPECT, with coronary angiography as the reference standard. RESULTS: The overall sensitivity of MR imaging for depicting at least one coronary artery with significant stenosis was 90% (69 of 77 patients). The sensitivities of MR imaging for depiction of single-, double-, and triple-vessel stenoses were 85% (33 of 39 patients), 96% (22 of 23 patients), and 100% (15 of 15 patients), respectively. The specificity of MR imaging for identification of patients with significant coronary artery stenoses was 85% (23 of 27 patients). The areas under the receiver operating characteristic curve for detection of significant stenosis in individual coronary arteries were 0.888 (observer 1) and 0.911 (observer 2) for MR imaging and 0.707 (observer 1, P <.001) and 0.750 (observer 2, P <.001) for SPECT. CONCLUSION: In patients without myocardial infarction, stress enhancement at dynamic MR imaging correlates more closely with quantitative coronary angiography results than does stress enhancement at SPECT.

Adult↗