PubMed Health⌕ Search

Biomedical subjects

Tadanori Hirano

Publications and source records attributed to Tadanori Hirano.

At least 19 recordsLinked to original sources
PubMed2006

Detection of coronary artery stenosis with whole-heart coronary magnetic resonance angiography.

OBJECTIVES: We sought to determine the diagnostic performance of whole-heart coronary magnetic resonance (MR) angiography for detecting significant coronary artery disease. BACKGROUND: The accuracy of whole-heart coronary MR angiography has not been determined in a large number of patients. METHODS: Three-dimensional coronary MR angiograms covering the entire heart were obtained during free breathing in 131 patients. Images were acquired during a patient-specific time window in the cardiac cycle with minimal motion of the coronary artery. Significant coronary artery disease was defined on X-ray coronary angiography as a diameter reduction of > or =50% in coronary arteries with a reference diameter of > or =2 mm. RESULTS: The acquisition of MR angiography was completed in 113 (86%) of 131 patients, with an imaging time averaged at 12.9 +/- 4.3 min. On a patient-based analysis, the sensitivity, specificity, positive and negative predictive value, and accuracy of MR angiography were 82% (95% confidence interval [CI] 69% to 91%), 90% (95% CI 79% to 96%), 88% (95% CI 74% to 95%), 86% (95% CI 75% to 93%), and 87% (95% CI 79% to 92%), respectively. These values in the individual segments were 78% (95% CI 68% to 85%), 96% (95% CI 95% to 97%), 69% (95% CI 60% to 77%), 98% (95% CI 96% to 98%), and 94% (95% CI 96% to 96%). CONCLUSIONS: Whole-heart coronary MR angiography allows for noninvasive detection of significant narrowing in coronary arterial segments with a diameter of > or =2 mm with moderate sensitivity and high specificity.

Aged↗
PubMed2005

Basket pattern blood flow signals discovered in a case of splenic hamartoma by power Doppler ultrasonography.

We present the gray-scale ultrasonography (GSUS), power Doppler ultrasonography (PDUS), abdominal computed tomography (CT), and magnetic resonance imaging (MRI) findings for a case of splenic hamartoma in a 27-year-old man, showing a phi 50 mm homogeneous, iso- and hypo-echoic splenic mass with evidence of a small plural cystic lesion. This splenic hamartoma showed increased vascularity on power Doppler sonograms. PDUS showed multiple circular blood flow signals inside the mass (i.e. a basket pattern), which was consistent with the small plural cystic lesion shown by GSUS. Spectral analysis also confirmed arterial and venous flow. CT scans showed that the mass had low-density relative to the normal spleen and MRI showed that the mass was isodense, relative to the normal spleen. Therefore, CT and MRI are not useful for the diagnosis of splenic hamartoma. Ultrasonography can be used to diagnose splenic hamartoma without administration of a contrast material and therefore is an indispensable method for the diagnosis of splenic hamartoma.

Adult↗
PubMed2005

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↗
PubMed2005

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↗
PubMed2005

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↗
PubMed2005

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↗
PubMed2004

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↗
PubMed2004

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↗
PubMed2004

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↗
PubMed2003

Stent-graft detachment from aortic wall after stent-graft repair of acute aortic dissection.

Preliminary studies have demonstrated that stent-graft repair is an attractive method for treatment of aortic dissection. However, few reports have described long-term results. A 72-year-old woman with acute type B aortic dissection underwent stent-graft repair. The entry was closed, and the false lumen disappeared completely. The postoperative course was uneventful for 4 years 5 months, when detachment of the stent graft from the aortic wall was noted. Because the device appears to be stable, follow-up is on an outpatient basis.

Aged↗
PubMed2003

Acute and contained rupture of the descending thoracic aorta: treatment with endovascular stent grafts.

PURPOSE: The purpose of this study was to evaluate feasibility and safety of endovascular stent grafting for the treatment of patients with rupture of the descending thoracic aorta. METHODS: Thirteen patients with rupture of the descending thoracic aorta were treated with endovascular stent grafting. Six patients were treated on the day of diagnosis because their vital signs were unstable, and the other seven patients were treated electively. Five patients had infection or potential infection, and the other eight patients did not. Expanded polytetrafluoroethylene-covered or polyester-covered Z stents were used in all patients. RESULTS: Stent grafts were successfully placed in all patients. No endoleaks were observed at the end of the procedure. However, rebleeding was observed within 2 weeks of the procedure in two patients with infection. Six patients (46%) died within 5 months of the procedure (mean survival period, 61 +/- 60 days). All five patients with infection (100%) died, and only one of eight patients without infection (13%) died (P <.01). The remaining seven patients are alive during the mean follow-up period of 21 months (overall survival rate, 54%), although additional surgical interventions, including surgical conversion in one case and upper extremity extraanatomic bypass in the other, were necessary in two of these patients. CONCLUSION: Endovascular stent grafting may be a safe and feasible method for the treatment of rupture of the descending thoracic aorta in selected patients without infection. However, its usefulness in terms of long-term prognosis appears to be extremely limited, especially in patients with infection.

Acute Disease↗
PubMed2003

Increased myocardial uptake of iodine-123 metaiodobenzylguanidine on delayed images, compared with early images, in patients with multiple system atrophy.

We present 2 interesting cases of multiple system atrophy in which increased myocardial iodine-123 metaiodobenzylguanidine uptake was observed on delayed images (3 hours after injection) compared with early images (15 minutes after injection). These findings have not been previously described. The duration of symptoms was less than 1 year in both these patients. The mechanism responsible for these findings is not clearly understood, but could be related to the pathophysiological changes in the early stage of multiple systemic atrophy.

3-Iodobenzylguanidine↗
PubMed2003

Acute myocardial infarction: myocardial viability assessment in patients early thereafter comparison of contrast-enhanced MR imaging with resting (201)Tl SPECT. Single photon emission computed tomography.

PURPOSE: To compare contrast material-enhanced magnetic resonance (MR) imaging with resting thallium 201 ((201)Tl) single photon emission computed tomography (SPECT) for predicting myocardial viability in patients early after acute myocardial infarction. MATERIALS AND METHODS: Inversion-recovery contrast-enhanced MR images and resting (201)Tl SPECT images were obtained in 22 patients after acute myocardial infarction. The (201)Tl SPECT images were obtained 4.3 days +/- 0.2 (standard error) after the onset of myocardial infarction. Contrast-enhanced MR imaging was performed 7.9 days +/- 1.6 after (201)Tl SPECT. Transmural extent of hyperenhancement on contrast-enhanced MR images and regional (201)Tl activity were quantitatively analyzed with a 12-segment model. Regional wall thickening on follow-up cine MR images obtained 67 days +/- 17 after contrast-enhanced MR imaging was used as an index for myocardial viability. Statistical analyses were performed with the chi(2) and two-tailed Student t tests. RESULTS: Both contrast-enhanced MR and resting (201)Tl SPECT images showed significant correlations with regional wall thickening on follow-up cine MR images. The sensitivity, specificity, and accuracy of contrast-enhanced MR imaging in the prediction of viable myocardium were significantly higher than those of resting (201)Tl SPECT (98.0% vs 90.3%, P <.01; 75.0% vs 54.4%, P <.05; and 92.0% vs 81.1%, P <.001, respectively). CONCLUSION: Delayed contrast-enhanced MR imaging can help predict myocardial viability as seen on follow-up cine MR images after acute myocardial infarction, with significantly improved sensitivity, specificity, and accuracy in comparison with those of resting (201)Tl SPECT.

Female↗
PubMed2002

Transluminal stent-graft placements for the treatments of acute onset and chronic aortic dissections.

BACKGROUND: Transluminal stent-graft placement (TSGP) for aortic dissection is a relatively new procedure. We performed TSGPs to seal the primary entry site to treat and prevent complications of aortic dissection. The early to mid-term outcomes were analyzed. METHODS AND RESULTS: Thirty-seven patients with a primary intimal tear in descending aorta underwent TSPG. TSGP was performed in 16 acute onset dissections (AOD) with dissection-related complications instead of emergency surgery. Eight AOD without complications were treated to prevent aneurysmal enlargement. Thirteen chronic dissections were treated to prevent rupture. TSGP was technically successful in all cases. One patient with prehospital rupture died. The hospital mortality rate was of 2.7% overall, 6.3% in AOD with complications, 0% in AOD without complications and in chronic dissections. One persistent endoleak required open surgery, and 1 intimal tear was caused by the stent-graft, necessitating an additional TSGP. The primary success rate was 94.4% overall. After hospital discharge, no patient died or suffered aortic rupture during an average follow-up of 24.5 months. New intimal tears caused by the stent-grafts and a secondary endoleak developed in 3 AOD patients. One open procedure and 2 additional TSGPs were performed. Actuarial survival rate and cardiovascular event-free rate at 2 years are 97.3% and 78.3% overall, 93.8% and 48.0% in AOD with complications, 100% and 87.5% in AOD without complications, and both 100% in chronic dissections. CONCLUSIONS: TSGP is a reasonable treatment option for aortic dissection. However, delayed intimal tear formations caused by the stent-graft is a problem that requires further investigation.

Acute Disease↗
PubMed2002

Aortic arch aneurysms: treatment with extraanatomical bypass and endovascular stent-grafting.

Endovascular repair of thoracic aortic aneurysms is emerging as an attractive alternative to surgical graft replacement. However, patients with aortic arch aneurysms are often excluded from the target of endovascular repair because of lack of suitable landing zones, especially at the proximal ones. In this paper we describe our method for treating patients with aortic arch aneurysms using a combination of extraanatomical bypass surgery and endovascular stent-grafting.

Aged↗