Unusual MRI findings in primary central nervous system lymphoma presenting diffuse linear enhancements located in the perivascular space.
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Central Nervous System Neoplasms↗
Biomedical subjects
Kan Takeda
Publications and source records attributed to Kan Takeda.
Apparent diffusion coefficient in malignant lymphoma and carcinoma involving cavernous sinus evaluated by line scan diffusion-weighted imaging.
PURPOSE: To evaluate the apparent diffusion coefficient (ADC) of malignant lymphomas and carcinomas involving cavernous sinus by line scan diffusion-weighted imaging (LSDWI) and to determine the usefulness of this method for differentiating between the two tumors. MATERIALS AND METHODS: Four patients with malignant lymphomas and six patients with carcinomas were prospectively studied. LSDWI images were obtained with two different b values of 5 seconds/mm(2) and 1000 seconds/mm(2) in the coronal plane. The ADC values of the two types of tumors were calculated and compared. RESULTS: LSDWI provided diagnostic images with minimum susceptibility artifacts and enabled measurement of the ADC. The ADC value (mean +/- SD) was 0.51 +/- 0.06 x 10(-3) mm(2)/second in malignant lymphomas and 0.99 +/- 0.08 x 10(-3) mm(2)/second in carcinomas. A significant difference in ADC values was found between the two (P < 0.01). CONCLUSION: Malignant lymphomas showed significantly lower ADC value than carcinomas. ADC provides additional useful information about differentiation between these tumors.
Adult↗
Improvement of regional cerebral blood flow after oral intake of branched-chain amino acids in patients with cirrhosis.
AIM: To evaluate the effect of oral intake of branched-chain amino acids (BCAA) on brain perfusion in patients with liver cirrhosis. METHODS: Single photon emission computed tomography scans were performed in 43 patients with cirrhosis and in 15 age-matched healthy subjects. Twenty-nine out of forty-three patients were randomly treated with either BCAA granules or placebo, and single photon emission computed tomography was performed before and after the treatment. We measured the regional cerebral blood flow values using a three-dimensional stereotaxic region of interest template. RESULTS: Cirrhotic patients had regions of significant hypoperfusion in the bilateral central (right P=0.039, P<0.05; left P=0.006 P<0.01), parietal (right P=0.018, P<0.05; left P=0.009, P<0.01), angular (right P=0.039, P<0.05; left P 0.008, P<0.01), and left pericallosal segments (P=0.038 P<0.05) as compared with healthy subjects. A significant increase in cerebral perfusion was observed 70 min after the oral intake of BCAA in the angular (right P=0.012, P<0.05; left P=0.049, P<0.05), temporal (right P=0.012, P<0.05; left P=0.038, P<0.05), pericallosal segments (right P=0.025, P<0.05; left P=0.049, P<0.05) and left precentral (P=0.044, P<0.05), parietal (P=0.040, P<0.05) and thalamus (P=0.033, P<0.05). No significant change in perfusion was observed in the placebo group. CONCLUSION: Administration of BCAA rapidly improves cerebral perfusion.
Administration, Oral↗
Contrast-enhanced MR imaging for evaluation of coronary artery disease before elective repair of aortic aneurysm.
PURPOSE: To prospectively evaluate the accuracy of first-pass contrast material-enhanced magnetic resonance (MR) imaging during stress and delayed contrast-enhanced MR imaging in the detection of significant coronary artery disease in patients before elective repair of aortic aneurysm. MATERIALS AND METHODS: The study was approved by the institutional ethics committee, and informed consent was obtained from all patients. MR imaging was performed in 49 patients (42 men and seven women; mean age, 72.2 years; age range, 58-85 years) before the elective repair of atherosclerotic aortic aneurysms. Thirty-two patients had an abdominal aneurysm, 12 had a thoracic aneurysm, and five had a thoracoabdominal aneurysm. First-pass contrast-enhanced MR images were obtained with short-axis sections encompassing the entire left ventricular myocardium in the resting state and during pharmacologic stress. Inversion-recovery-prepared delayed contrast-enhanced MR images were obtained with breath holding to evaluate for the presence of infarction. All patients underwent coronary angiography within 2 weeks of MR imaging, and these findings were used as the standard of reference. The diagnostic results of first-pass contrast-enhanced MR imaging, delayed contrast-enhanced MR imaging, and a combination of both MR imaging methods in the detection of significant coronary artery disease were expressed as sensitivity, specificity, and accuracy. RESULTS: Coronary angiography depicted a clinically significant stenosis (>70% luminal diameter narrowing) in the coronary artery in 34 of the 49 patients (69%). First-pass contrast-enhanced MR imaging depicted stress-induced hypoenhancement in 27 of those 34 patients (79%). Delayed myocardial enhancement was observed in 17 of the 34 patients (50%). The overall sensitivity of rest-stress first-pass contrast-enhanced MR imaging and delayed contrast-enhanced MR imaging combined in the prediction of at least one coronary artery with significant stenosis was 88% (30 of 34 patients). The specificity and accuracy of MR imaging were 87% (13 of 15 patients) and 88% (43 of 49 patients), respectively. CONCLUSION: Contrast-enhanced MR imaging had an accuracy of 88% in the detection of significant coronary artery disease in patients with aortic aneurysm.
Aged↗
Assessment of coronary arteries with total study time of less than 30 minutes by using whole-heart coronary MR angiography.
This study had institutional review board approval, and all patients gave informed consent. The purpose of this study was to prospectively evaluate the use of whole-heart three-dimensional (3D) coronary magnetic resonance (MR) angiography in patients suspected of having coronary artery disease. Whole-heart coronary MR angiography was performed in 39 patients (30 men and nine women; mean age, 63.9 years +/- 15.6 [standard deviation]) by using a steady-state free precession sequence with free breathing. Twenty patients (16 men and four women; mean age, 64.9 years +/- 11.7) also underwent conventional coronary angiography. MR angiography was successfully completed in 34 of 39 patients (87%); the average imaging time was 13.8 minutes +/- 3.8. Sensitivity and specificity of MR angiography for detecting significant stenosis were 82% (14 of 17 arteries) and 91% (39 of 43 arteries), respectively. Whole-heart coronary MR angiography with a navigator-gated steady-state sequence can enable reliable 3D visualization of the coronary arteries in patients suspected of having coronary artery disease.
Coronary Angiography↗
[Cardiovascular MR imaging].
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Coronary Angiography↗
Changes in false lumen after transluminal stent-graft placement in aortic dissections: six years' experience.
BACKGROUND: Transluminal stent-graft placements (TSGPs) are a new, less invasive procedure now recognized as the choice for aortic disease repair. Treatment of aortic dissections with TSGPs has resulted in good early results, but the long-term results and changes in the false lumen have not been elucidated in detail. METHODS AND RESULTS: TSGPs were performed in 49 patients with primary tears in their descending aortas, and the follow-up period ranged from 4 months to 6 years. The patients were divided into 32 acute-onset and 17 chronic dissections; of the acute-onset cases, there were 15 Stanford type A retrograde dissections. Periodic enhanced spiral CT was conducted after TSGP. The false lumen in the ascending aorta in 14 (93%) of the Stanford type A cases was obliterated completely within 3 months. The CT study was continued for >2 years for 17 acute-onset dissection and 11 chronic dissection patients. The average false lumen diameters of the proximal, middle, and distal descending aorta before treatment were 15.9, 16.2, and 15.6 mm in the acute-onset dissection group and 28.1, 25.2, and 21.0 mm in the chronic dissection group, respectively. The false lumen diameters 2 years after treatment were 3.0, 3.7, and 3.1 mm in the acute-onset dissection group and 10.6, 10.5, and 11.9 mm in the chronic dissection group, respectively. Two years after TSGPs, the false lumen of the thoracic aorta totally disappeared in 76% of the acute-onset dissection group and 36% of the chronic dissection group. No cases showed rupture after TSGP. CONCLUSIONS: Complete obliteration of the false lumen is more likely in acute-onset cases than in chronic cases.
Aged↗
Risk factors for the recurrence of hepatocellular carcinoma after radiofrequency ablation of hepatocellular carcinoma in patients with hepatitis C.
AIM: To analyze the risk factors of hepatocellular carcinoma (HCC) recurrence after radiofrequency ablation (RFA) treatment with HCV-associated hepatitis. METHODS: Twenty-six patients with HCV-associated HCC who were followed-up for more than 12 mo were selected for this study. Risk factors for distant intrahepatic recurrences of HCC were evaluated for patients in whom complete coagulation was achieved without recurrence in the same subsegment as the primary nodule. Twelve clinical and tumoral factors were examined: Age, gender, nodule diameter, number of primary HCC nodule, Child-Pugh classification, serum platelet, serum albumin, serum AST, post RFA AST, serum ALT, post RFA ALT, post RFA treatment. RESULTS: Distant recurrences of HCC in remnant liver after RFA were observed in 14 cases and in the number of primary HCC nodules (P = 0.047), and the serum platelets (P = 0.030), the clear difference came out by the recurrence group and the non-recurrence group. The cumulative recurrence rates after 1 and 2 years were 30.8% and 86.8%, respectively for primary multinodular HCC, and 15.4% and 29.5% respectively, for primary uninodular HCC. In addition the 1-year recurrence rates for patients with serum albumin more than 3.4 g/dL and less than 3.4 g/dL were 23.1% for both, but the 2-years recurrence rates were 89.0% and 23.1%, respectively. The number of primary HCC nodules (relative risk, 6.970; P = 0.016) were found to be a statistically significant predictor for poor distant intrahepatic recurrence by univariate analysis. CONCLUSION: Patients who have multiple HCC nodules, low serum platelets and low serum albumin accompanied by HCV infection, should be carefully followed because of the high incidence of new HCC lesions in the remnant liver, even if coagulation RFA is complete.
Aged↗
Late gadolinium-enhanced magnetic resonance imaging in acute and chronic myocardial infarction. Improved prediction of regional myocardial contraction in the chronic state by measuring thickness of nonenhanced myocardium.
OBJECTIVES: We sought to determine serial changes of enhanced and nonenhanced tissue on late gadolinium-enhanced cardiac magnetic resonance (CMR) imaging in patients with a myocardial infarction (MI) and to assess whether thickness of nonenhanced myocardium can improve the detection of preserved contractile function in the chronic state. BACKGROUND: Previous studies demonstrated that enhancement on late gadolinium-enhanced CMR images indicates myocardial necrosis, and nonenhancement shows the presence of viable myocardium. METHODS: The CMR studies were performed within one week (scan 1) and more than five months (scan 2) after the onset of MI in 18 patients. The area and mean thickness of enhanced tissue and nonenhanced myocardium were measured by using a 30-segment model. Systolic wall thickening on cine CMR at scan 2 was assessed for evaluating regional contractile function. RESULTS: The amount of enhanced tissue significantly decreased from scan 1 to 2 (22.1 +/- 14.0 ml vs. 15.0 +/- 9.3 ml, p < 0.001). The averaged thickness of nonenhanced myocardium in the infarct segments significantly increased from scan 1 to 2 (5.2 +/- 3.0 mm vs. 6.6 +/- 3.2 mm, p < 0.001). Receiver operating characteristic analysis demonstrated that the measurement of thickness of nonenhanced myocardium, compared with measurement of percent transmural enhancement, had better diagnostic accuracy for predicting improved systolic wall thickening form scan 1 to 2 in dysfunctional segments (Az 0.650 vs. 0.594, p < 0.05). CONCLUSIONS: The amounts of enhanced tissue and nonenhanced myocardium significantly altered from the acute to chronic state in MI patients. The diagnostic performance of CMR imaging for detection of preserved contractile function can be significantly improved by measuring thickness of nonenhanced myocardium in MI patients.
Aged↗
Evaluation of cingulate gyrus blood flow in patients with liver cirrhosis.
Although neuropsychological tests are commonly applied to detect minimal hepatic encephalopathy (HE) in patients with liver cirrhosis (LC), they provide no information about the cerebral regions involved. Recently, it has been reported that some populations of alcoholic cirrhotics, with mild HE, have reduced cerebral metabolic rate for glucose in bifrontal cortices and in the anterior cingulate gyrus. We evaluated the degree of reduction in blood flow at the anterior cingulate gyrus and the frontal lobes in cirrhotic patients who underwent single photon emission computed tomography (SPECT). Data were obtained from 47 cirrhotic patients and 47 subjects without LC. Three radiologists unaware of the results of laboratory tests visually evaluated the transaxial, coronal, and sagittal views of SPECT. The area and the degree of blood flow reduction in the anterior cingulate gyrus and frontal lobes were scored. Reduced blood flow in the anterior cingulate gyrus was observed in most LC patients. In patients without overt HE, poor performance in neuropsychological tests was correlated with reduced cerebral blood flow in the anterior cingulate gyrus. Blood flow in the anterior cingulate gyrus as measured by SPECT may be a simple and good indicator of cerebral functional changes in patients with LC.
Aged↗
Prospective study of arterial infusion chemotherapy followed by radiofrequency ablation for the treatment of liver metastasis of gastric cancer.
This prospective study was conducted to evaluate the efficacy of hepatic arterial infusion chemotherapy (HAIC) with use of an implanted port followed by radiofrequency (RF) ablation for the treatment of liver metastasis of gastric cancer. Seven patients without extrahepatic metastasis were enrolled. The maximum tumor size was less than 3 cm in one patient and 3.2-6.0 cm in the other six patients (mean, 4.4 cm +/- 1.5). Two patients had single lesions and the other five patients had two to six lesions each. The maximum tumor size was reduced to 3 cm or less (mean, 2.4 cm +/- 0.4; P < .03) after HAIC in all patients. The total number of tumors was reduced from 25 to 16. RF ablation was performed for all residual liver tumors, resulting in complete tumor necrosis. All but one patient are still living without intrahepatic recurrence, with a median survival time of 16.5 months.
Adult↗
Radiofrequency ablation for the treatment of hemorrhagic vaginal cancer.
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Aged↗
Outflow block secondary to stenosis of the inferior vena cava following living-donor liver transplantation?
Although it is well known that outflow block is caused by stenosis or occlusion of hepatic vein anastomoses following living donor liver transplantation (LDLT), there have been few reports on inferior vena cava (IVC) stenosis following LDLT. In this paper, we report two cases of IVC stenosis and hepatic vein outflow block following right hepatic LDLT in the absence of stenosis of any of the anastomoses. Both patients presented with liver dysfunction, an ascitic fluid volume of approximately 2000 mL, and congestion in their biopsy specimens, and venocavography demonstrated IVC stenosis with gradients of more than 10 mmHg in patients with a dominant inferior right hepatic vein (IRHV) anastomosis. After a Gianturco expandable metallic stent successfully implanted in the IVC, the patient's liver function recovered and the volume of ascitic fluid decreased. The pathogenesis of hepatic vein outflow block secondary to IVC stenosis following LDLT may involve the anastomosis with the IRHV, which is the dominant draining vein of the graft and larger than the RHV, caudal to the IVC stenosis and a significant IVC pressure gradient that results in increased IRHV pressure. In conclusion, it is important to include hepatic vein outflow block in the differential diagnosis when patients who have undergone right hepatic LDLT in which anastomosis of the large IRHV has been performed develop manifestations of liver dysfunction.
Adult↗
Diagnostic accuracy of stress first-pass contrast-enhanced myocardial perfusion MRI compared with stress myocardial perfusion scintigraphy.
OBJECTIVE: The purpose of this study was to determine the diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery prepared turbo fast low-angle shot (turbo FLASH) compared with stress myocardial perfusion scintigraphy. Recent studies show that first-pass contrast-enhanced myocardial perfusion MRI can provide noninvasive detection of low-limiting stenosis in the coronary artery. MATERIALS AND METHODS: First-pass contrast-enhanced MR images were acquired at rest and during stress in 40 patients with suspected coronary artery disease. All patients underwent thallium-201 SPECT without attenuation correction and coronary angiography. Two reviewers independently assigned one of five confidence grades without knowing the results of coronary angiography for receiver operating characteristic (ROC) analysis. Luminal stenosis >70% on coronary angiography was used as a reference standard. RESULTS: On coronary angiography, 70% or greater diameter stenosis of the coronary artery was observed in 21 (52.5%) of 40 patients. The areas under the ROC curve for detection of significant stenosis in the individual coronary artery were 0.86 (observer 1) and 0.84 (observer 2) for MRI. These values were 0.79 (observer 1, p = not significant) and 0.72 (observer 2, p = not significant) for 201Tl SPECT. CONCLUSION: The diagnostic accuracy of stress perfusion MRI acquired with saturation-recovery-prepared turbo FLASH was comparable with that of stress 201Tl SPECT. Stress first-pass contrast-enhanced MRI is a noninvasive technique that can be used as an alternative to stress myocardial perfusion scintigraphy.
Contrast Media↗
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↗
Acute bilateral medial medullary infarction: a unique 'heart appearance' sign by diffusion-weighted imaging.
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Aged↗
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↗