Biomedical subjects
Publications and source records attributed to T Shimono.
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OBJECTIVE: To clarify whether patients with clinical diagnoses of encephalitis/encephalopathy with a reversible lesion in the splenium of the corpus callosum (SCC) share common clinical features. METHODS: Possible encephalitis/encephalopathy patients with a reversible isolated SCC lesion on MRI were collected retrospectively. Their clinical, laboratory, and radiologic data were reviewed. RESULTS: Fifteen encephalitis/encephalopathy patients with a reversible isolated SCC lesion were identified among 22 patients referred for this study. All 15 patients had relatively mild clinical courses. Twelve of the 15 patients had disorders of consciousness. Eight patients had seizures, and three of them received antiepileptic drugs. All 15 patients clinically recovered completely within 1 month (8 patients within a week) after the onset of neurologic symptoms. The SCC lesion was ovoid in six patients; it extended irregularly from the center to the lateral portion of SCC in the other eight patients. Homogeneously reduced diffusion was seen in all seven patients who underwent diffusion-weighted imaging. There was no enhancement in the five patients so examined. The SCC lesion had completely disappeared in all patients at follow-up MRI exams between 3 days and 2 months after the initial MRI (within 1 week in eight patients). CONCLUSION: The clinical features among the affected patients were nearly identical, consisting of relatively mild CNS manifestations and complete recovery within 1 month.
Hundred and forty-one small peripheral adenocarcinomas 2 cm or less in diameter were retrospectively studied to determine the rationale of limited resection with curative intent. We used a conventional computed tomography (CT) which used 2.5 mm thick sections to examine only the main tumor during from March 1985 to May 1999 and a spiral CT which produced 2.5 mm thick sections of the entire lung field during from June 1999 to July 2003. The incidence of small peripheral adenocarcinoma significantly increased from 12.6% to 29.1%, suggesting an increase in the rate of detection with spiral CTs. During the spiral CT era, the percentage of females, pathological stage I a tumors, predominant ground-glass opacity (GGO) tumors and limited resection were significantly higher. The incidence of multiple adenocarcinomas 2 cm or less in diameter significantly increased 2.6% to 14.1%. It increases to 21.9% in small adenocarcinomas and 63.6% in predominant GGO type, when minute GGO lesion which have been followed in 5 patients by a watch and wait policy would be bronchioloalveolar carcinoma (BAC). In conclusion, a paradigm shift of the treatment for small peripheral adenocarcinoma should be warrant, because localized BAC as noninvasive cancer is not rare and often found as multiple BACs.
A surgical case of acute purulent pericarditis in 1-year 2-month old boy who developed pericardial tamponade rapidly is reported. A subxiphoid pericardiectomy through a median incision was performed. Haemophilus influenzae was isolated from the effusion. He recovered successfully with an administration of antibiotics after the drainage procedures and did not develop constructive pericarditis. Our experience suggested that early subxiphoid pericardial drainage was effective in treatment of acute purulent pericarditis.
We studied multiple primary lung cancers (MPLCs) in 921 patients who had undergone operation for primary lung cancer since March 1979 in Mie University Hospital. There were 14 synchronous and 5 metachronous MPLCs. Combination of synchronous MPLCs were adenocarcinoma (ADC)/ADC in 7, squamous cell carcinoma (SCC)/SCC in 3, and ADC/adenosquamous cell carcinoma, ADC/small cell carcinoma, ADC/large cell carcinoma and multiple AAH in one. The incidence of synchronous MPLCs was 0.7% (6/815 pts) before May 1999 and 7.5% (8/106 pts) after June 1999 when HRCT was introduced for preoperative evaluation and postoperative follow-up. Six cases with multiple bronchioloalveolar carcinomas (BACs) have undergone operation for last 5 years. Most of them were roentgenographically occult and the operative outcome was good in spite of limited resection. In summary, we need new strategy of diagnosis and operative procedure for peripheral small adenocarcinoma, because multiple MPLCs of BAC are not rare.
UNLABELLED: [18F]fluorodeoxyglucose (FDG) and positron emission tomography (PET) may be used to examine changes in cerebral glucose metabolism in two physiological conditions. We proposed and evaluated a double injection-single session FDG method with biological constraints for this purpose. METHODS: Simulated brain time-radioactivity curves (TACs) generated by using a plasma TAC from an actual study and physiological combinations of input values in a kinetic model were analyzed to evaluate the accuracy of the proposed method. The reproducibility of the estimated values obtained by this method was tested in five normal volunteers who were studied with a dynamic PET scan and two injections of FDG in a single session while fasting. RESULTS: The simulation study showed that the estimated values obtained by the proposed method agreed well with the input values. In the human study, plasma glucose levels were 5.3 +/- 0.2 and 5.0 +/- 0.2 mM in the first and second measurements, respectively. The difference between the plasma glucose measurements was small but statistically significant (p < 0.05). Although no systematic deviations were noted in K*1 or rCMRglc, there were small deviations in K* (less than 10%) and LC (less than 5%) with a statistical significance (p < 0.01). CONCLUSION: The deviation between the measurements in K* and LC seemed to relate to the difference in the plasma glucose level. The double-injection FDG method with biological constraints can be used to estimate rCMRglc and LC sequentially in a single PET scanning session.
UNLABELLED: The purpose of this study was to validate a double-injection (DI) method with N-isopropyl-[123I]p-iodoamphetamine (IMP) to measure regional cerebral blood flow (rCBF) twice in a single session of dynamic SPECT and to elucidate a possible role of this method to identify patients with occlusive disease of major cerebral arteries, who might benefit from cerebral revascularization procedures (CR). MATERIALS AND METHODS: Fourteen patients with occlusion or severe stenosis of the internal carotid or middle cerebral artery were studied before and after CR to assess hemodynamic changes after revascularization treatment. We quantitatively measured rCBF before and after acetazolamide (ACZ) challenge along with cerebrovascular reserve capacity (CVR) with two injections of IMP in a single session of dynamic SPECT scans (DI method). The reliability and reproducibility of the DI method were validated by means of a simulation study and in eight patients who were examined without ACZ challenge to measure baseline rCBF twice. RESULTS: The analysis of simulated noisy data with realistic noise levels showed that the errors of the estimates for the first and the second rCBF and for the increase in rCBF were 2.6%, 8.1% and 10.4%, respectively. In the 8 patients examined by the DI method to measure baseline rCBF twice, the mean and the SD of percentage differences between the two consecutive measurements in rCBF were -1.3% and 5.5%, respectively. Eight out of 14 patients with occlusive disease had at least one region with a CVR less than 10%. They showed a significant increase in resting rCBF after CR, not only in the ipsilateral hemisphere (from 26.1 +/- 6.4 to 33.4 +/- 4.7) but also in the contralateral one (from 28.3 +/- 7.0 to 34.7 +/- 4.7) with a recovery of the ipsilateral CVR from 9.3 +/- 17.2 to 41.2 +/- 20.1%. The remaining six patients with good-moderate CVR did not show an increase in rCBF after CR (from 28.0 +/- 2.7 to 28.3 +/- 3.4). The three of them with a moderate CVR (10-25%) before CR showed normalization of CVR after CR. CONCLUSION: Patients with decreased rCBF and reduced CVR benefited from CR in terms of an increase in rCBF and recovery of CVR. The quantitative double-injection IMP-SPECT has the ability to identify those patients who may benefit from CR.
True aneurysm of the coronary artery in Marfan syndrome is very rare. We present a patient with Marfan syndrome who had aneurysms from the ascending aorta to the thoracoabdominal aorta and a large aneurysm of the left main coronary artery after an original Bentall operation. Prosthetic graft replacement of total aorta, coronary artery bypass grafting, and removal of the aneurysm of the left main coronary artery were successfully performed.
PURPOSE: To investigate efficacy of stent-graft repair for the treatment of patients with chronic aortic dissection. MATERIALS AND METHODS: Fifteen patients with chronic aortic dissection were treated with endovascular stent-grafts. Entry tears were located in the descending thoracic aorta in all patients. The mean maximum diameter of the descending thoracic aorta was 47 mm +/- 8. The mean diameter of the true lumen at the same level was 20 mm +/- 5. The mean interval between diagnosis and stent-graft procedure was 32 months +/- 91. Stent-grafts were fabricated from expanded polytetrafluoroethylene and Z-stents. RESULTS: Stent-grafts were placed successfully in all patients. Two stent-grafts were required in one patient. Entry closure and thrombosis of the false lumen of the descending thoracic aorta were also achieved in all patients. No procedure-related complications were observed except for postimplantation syndrome, including fever and leukocytosis. The diameter of the true lumen was significantly increased (mean, 31 mm +/- 6) at the level of the descending thoracic aorta (P <.01) and the diameter of the aorta was significantly decreased (mean, 44 mm +/- 8) at the same level (P <.01). There were no deaths and no instances of aortic rupture during the subsequent average follow-up period of 24 months. Secondary stent-graft procedures were required to treat the abdominal component of dissection during follow-up in one patient. CONCLUSIONS: Stent-graft repair of chronic aortic dissection is a safe and effective method and may be an alternative to surgical graft replacement in selected patients. However, further evaluation is mandatory before this method is widely employed.
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PURPOSE: Stent-graft repair of acute aortic dissection has only recently begun, and the true efficacy and safety of this technique have not yet been clarified. In this report, we describe a significant, previously unreported complication following stent-graft repair of acute aortic dissection. MATERIALS AND METHODS: Fourteen patients with acute aortic dissection underwent stent-graft repair. All of the entry tears were located in the descending thoracic aorta. Five patients had type A aortic dissection, and nine patients had type B aortic dissection. The entry tears were closed with stent-grafts, which were fabricated from expanded polytetrafluoroethylene and Z-stents. RESULTS: Stent-graft placement was successfully performed without any complications in all patients. Entry closure was achieved in 13 (93%) of 14 patients. The mean follow-up period was 18 months (range, 9 days to 36 months). During this period, four patients had saccular aneurysms in the proximal descending thoracic aorta. A saccular aneurysm was noted during a mean follow-up period of 63 days (range, 38-99 days). Two of these patients were treated with stent-grafts. Conventional surgical repair is planned in one patient. The other patient is being treated with conservative management. CONCLUSIONS: Stent-graft repair is a technically feasible and effective method for the treatment of acute aortic dissection in selected patients. However, careful follow-up is mandatory to check for the development of saccular aneurysms.
PURPOSE: The current therapy for type A aortic dissection is ascending aortic replacement. Operative mortality and morbidity rates have been markedly improved because of recent advances in surgical techniques and anesthesiology. However, type A aortic dissection with an entry tear in the descending thoracic aorta is still a surgical challenge because of the need for extensive aortic replacement. METHODS: Ten patients with type A aortic dissection were treated with endovascular stent-grafts. The false lumen of the ascending aorta was patent in five patients, and it was thrombosed in the other five patients. The entry tears were located in the descending thoracic aorta in all cases. Seven patients had acute dissection, and three patients had subacute dissection. Four patients had pericardial effusion. Stent-grafts were fabricated from expanded polytetrafluoroethylene and Z-stents. RESULTS: Entry closure was achieved in all patients. Complete thrombosis of the false lumen of the ascending aorta was observed after stent-grafting in all patients. A second stent-graft was required in two patients to obtain complete thrombosis of the false lumen of the descending thoracic aorta. No procedure-related complications were observed, with the exception of a minor stroke in one patient. During a mean follow-up period of 20 months, no aortic rupture or aneurysm formation was noted in either the ascending or descending thoracic aorta, and all patients were alive and doing well. The abdominal aortic aneurysm enlarged after stent-grafting in one patient, and this was treated by closing the fenestrations of the abdominal aorta with stent-grafts. CONCLUSION: Stent-graft repair of aortic dissection with an entry tear in the descending thoracic aorta is a safe and effective method and may be an alternative to surgical graft replacement in highly selected patients.
PURPOSE: To evaluate the sensitivity and specificity of breath-hold magnetic resonance (MR) flow measurement for detection of significant stenosis in internal mammary artery bypass grafts. MATERIALS AND METHODS: Twenty-six consecutive patients who had undergone coronary artery bypass surgery were examined. Breath-hold velocity-encoded cine MR images were obtained at the midpoint of the internal mammary artery between its origin from the subclavian artery and the distal anastomosis to the left anterior descending artery. RESULTS: MR images were obtained successfully in 24 patients. At conventional angiography, no significant stenosis was observed in 17 patients (group A), and significant stenosis (diameter > 70%) was observed in seven patients (group B). The mean diastolic-to-systolic peak velocity ratio in group B (0.61 +/- 0.44 [SD]) was significantly lower than that in group A (1.88 +/- 0.96; P <.01). Evaluation of graft stenosis with the diastolic-to-systolic peak velocity ratio revealed a sensitivity of 86% and a specificity of 88%. The mean blood flow rate at baseline in group B (16.9 mL/min +/- 5.5) was significantly lower than that in group A (79.8 mL/min +/- 38.2; P <.01). The sensitivity and specificity of MR blood flow measurement in predicting significant stenosis were 86% and 94%, respectively. The mean pharmacologic flow reserve ratios were 2.00 +/- 1.43 in group A and 1.39 +/- 1.46 in group B (P >.05). CONCLUSION: Fast MR blood flow measurement at baseline is highly useful for predicting significant stenosis in internal mammary arterial grafts.
The patient was a 59-year-old female who was admitted to the hospital due to acute pain of bilateral legs, a numbness of right hand and anarthria. Angiography of extremities revealed total occlusion of right ulnar artery, left radial artery and bilateral popliteal arteries. Brain MRI revealed multiple small infarctions. Echocardiography revealed a mass in the left atrium. She was diagnosed as multiple embolism including cerebral embolism caused by left atrial myxoma. Open heart surgery immediately after the attack is generally considered contraindicated due to problems of hemorrhagic infarction or brain edema. But, relapse of embolism may deteriorate the condition and miss the timing of surgery. Thus we performed removal of left atrial myxoma 4 days after the attack. The postoperative course was uneventful. This is a few report about open heart surgery immediately after the attack. We report about the indication and the optimal timing of open heart surgery following cerebral embolism.
A 60-year-old man, who had undergone implantation of a transvenous pacemaker system on the left chest wall for sick sinus syndrome 19 years ago, was admitted because of endocarditis with septicemia and lung abscess 2 months after reimplantation of the generator. His blood culture revealed Staphylococcus aureus. Following debridement of the infected pacemaker pocket and antibiotics therapy, we tried to remove the pacemaker system under cardiopulmonary bypass 1 month after admission. In intraoperative inspection, the electrodes had become firmly encased with fibrous tissue within the tricuspid valve and the right ventricle. After the operation, antibiotic therapy was performed for 4 weeks. His postoperative course was uneventful. Patients with pacemaker infection should undergo aggressive total removal of the pacemaker system, particularly incase with endocarditis and bacteremia.
The purpose of this study was to compare short inversion time inversion recovery (STIR) fast spin-echo (FSE), and fat-saturated T2-weighted FSE sequences in terms of uniformity of fat suppression and lesion conspicuity for magnetic resonance (MR) imaging of the neck and thorax. STIR FSE and fat-saturated T2-weighted FSE images were scored for uniformity of fat suppression (n = 40) and lesion conspicuity (n = 35). Five-point rank score analyses were utilized by three experienced radiologists. The mean scores of STIR and fat-saturated FSE techniques for uniformity of fat suppression were 4.3 and 2.3, respectively (P < 0.0001). The mean scores of STIR and fat-saturated FSE techniques for lesion conspicuity were 4.2 and 3.5, respectively (P < 0.0001). Insufficient fat suppression was prominent in the mandible, supraclavicular region, anterior mediastinum, epipericardial fat, and subdiaphragmatic fat. In addition, fat-saturated T2-weighted FSE showed inadvertent water suppression in 25%. The STIR FSE technique was superior to the fat-saturated FSE technique for cervical and thoracic MR imaging.
We developed and evaluated a method to measure rCBF without any blood sampling by using iodine- 123 IMP and SPECT. An integral of arterial input function, the integral taken from the value 0 to T of the variable Ca(t)dt, can be expressed as TC(T)/CO, where TC(T) is radioactivity delivered to the body in T minutes and CO is cardiac output. If T is acceptably small, rCBF can be determined by means of a microsphere model analysis with IMP as Cb(T)/(TC(T)/CO), where Cb(T) is cerebral radioactivity at T minutes. We derived TC(T) and CO from a chest dynamic scan. The method was applied to 45 patients who underwent rCBF studies (58 studies) with arterial blood sampling (ABS). Data from the chest scan were analyzed in comparison with ABS data in the first 28 studies, and equations for correction yielding an accurate TC(T)/CO were derived. The validity of the proposed method was evaluated in the subsequent 30 studies. The method yielded rCBF (rCBF-test) which agreed well with rCBF obtained by a two-compartment model analysis of dynamic SPECT and ABS data (rCBF-ref) with the mean and SD of differences between rCBF-test and rCBF-ref being 1.0 and 2.7 ml/100 g/min, respectively. In eleven subjects who underwent more than two studies, a percentage change in rCBF-test between the studies also closely approximated that of rCBF-ref (y = 1.11 x + 2.63, r = 0.92). The method can be used with acceptable reliability to measure rCBF without any blood sampling.
We report a 75-year-old man with a ruptured acute thoracic aortic dissecting hematoma treated using endovascular stent grafting and video-assisted thoracoscopic surgery. This less invasive therapy is a good therapeutic option even in ruptured acute aortic dissections, particularly given the difficulty of surgery.