PURPOSE: To demonstrate the feasibility of using a combination of x-ray fluoro- scopic and magnet... more PURPOSE: To demonstrate the feasibility of using a combination of x-ray fluoro- scopic and magnetic resonance (MR) fluoroscopic (ie, x-ray/MR fluoroscopy) guid- ance for left ventricular (LV) catheterization and transendocardial delivery of extra- cellular tissue markers. MATERIALS AND METHODS: Experiments were performed in six dogs by using an x-ray/MR fluoroscopy system. The arterial guide wire and catheter were ad- vanced
In the last decade, spiral computed tomography (CT) and magnetic resonance (MR) angiography (MRA)... more In the last decade, spiral computed tomography (CT) and magnetic resonance (MR) angiography (MRA) have become a viable alternative to conventional angiography in the diagnosis of acute pulmonary embolism. However, patients with dyspnea are often unable to hold their breath for a longer time and thus image degradation is frequently observed. Consequently, an imaging sequence that allows free breathing is desirable. The aim of this animal study was to compare contrast-enhanced spiral CT, MRA and a real-time MR sequence, the latter without breath-hold, with pulmonary angiography as reference gold standard. Nine pigs with artificially induced pulmonary embolism underwent this multimodality comparison. All images were independently evaluated for the presence of pulmonary emboli by two reviewers. Forty-three filling defects were detected by conventional angiography on lobar and segmental levels. Sensitivity of CT images was 72.1 and 69.8% for Readers 1 and 2, respectively, and sensitivity of MRA images was 79.1 and 81.4%. With real-time MR imaging, however, the detection rate was 97.7% for both readers. We conclude that, under experimental conditions, real-time MR imaging without the use of radiation or iodinated contrast material is comparable with angiography in the detection of pulmonary emboli.
The aim of the study was to compare, in patients with chronic ischaemic cardiomyopathy, contrast-... more The aim of the study was to compare, in patients with chronic ischaemic cardiomyopathy, contrast-enhanced cardiovascular magnetic resonance (ce-CMR) imaging and a combined (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and (99m)Tc-sestamibi single-photon emission computed tomography (SPECT) protocols for the prediction of functional recovery after revascularization, as assessed by cine CMR. Twenty-nine patients with ischaemic cardiomyopathy (ejection fraction 32 +/- 10%) were investigated with ce-CMR and PET/SPECT. For the assessment of global and regional functions, cine CMR was performed at baseline and at 6 months follow-up. For ce-CMR, the segmental extent of hyperenhancement (SEH) was quantitated, and for PET/SPECT, different viability categories were defined according to a validated quantitative protocol. Functional improvement was related to the SEH by ce-CMR, as well as to the viability categories by PET/SPECT. Sensitivity and specificity for the prediction of functional recovery at follow-up was 97 and 68% for ce-CMR and 87 and 76% for PET/SPECT. The positive predictive value was identical for both techniques (73%). However, ce-CMR achieved a higher negative predictive value (93 vs. 77%, respectively), indicating that ce-CMR may be superior to PET/SPECT for the identification of segments unlikely to recover function after revascularization. Both methods had a similar yield in the prediction of global functional improvement. ce-CMR is comparable with a PET/SPECT imaging protocol for the prediction of regional and global functional improvement after revascularization. However, ce-CMR may be superior to nuclear imaging for the identification of segments that are unlikely to recover function at follow-up.
Zusammenfassung Die Tuba Eustachii regelt Belüftung, Protektion und die Drainage des Mittelohrs. ... more Zusammenfassung Die Tuba Eustachii regelt Belüftung, Protektion und die Drainage des Mittelohrs. Funktionsstörungen treten überwiegend im Kindesalter auf. Folgen sind Otitis und Hörminderung. Der wichtigste Tubenmuskel ist der M. tensor veli palatini. Die Komplexität der funktionellen Anatomie und der Physiologie der Tuba auditiva führen dazu, dass kein Untersuchungsverfahren allein in der Lage ist, allen diagnostischen Erfordernissen gerecht zu werden. Der prädiktive
The prevalence of systemic atherosclerosis and overactive bladder/detrusor overactivity increases... more The prevalence of systemic atherosclerosis and overactive bladder/detrusor overactivity increases almost simultaneously with age but an association between these diseases has not yet been proved. We evaluated changes in bladder function and morphology, including vascularization, in apoE(-/-)LDLR(-/-) double knockout mice with systemic atherosclerosis but without central nervous system involvement. Cystometry was performed in awake, freely moving 60-week-old apoE(-/-)LDLR(-/-) mice and C57BL/6N controls. The mice were sacrificed and perfused with Microfil® contrast medium. The bladder was excised, dissected and scanned by nano-computerized tomography, including 3-dimensional reconstruction. Samples then underwent histomorphological analysis. In apoE(-/-)LDLR(-/-) mice cystometry revealed a significant decrease in the peak-peak interval, micturition interval, functional bladder capacity and micturition volume. However, maximum bladder pressure increased. Nano-computerized tomography r...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2004
The aim of this study was to validate Quantitative Gated SPECT (QGS) and 4D-MSPECT for assessing ... more The aim of this study was to validate Quantitative Gated SPECT (QGS) and 4D-MSPECT for assessing left ventricular end-diastolic and systolic volumes (EDV and ESV, respectively) and left ventricular ejection fraction (LVEF) from gated (18)F-FDG PET. Forty-four patients with severe coronary artery disease were examined with gated (18)F-FDG PET (8 gates per cardiac cycle). EDV, ESV, and LVEF were calculated from gated (18)F-FDG PET using QGS and 4D-MSPECT. Within 2 d (median), cardiovascular cine MRI (cMRI) (20 gates per cardiac cycle) was done as a reference. QGS failed to accurately detect myocardial borders in 1 patient; 4D-MSPECT, in 2 patients. For the remaining 42 patients, correlation between the results of gated (18)F-FDG PET and cMRI was high for EDV (R = 0.94 for QGS and 0.94 for 4D-MSPECT), ESV (R = 0.95 for QGS and 0.95 for 4D-MSPECT), and LVEF (R = 0.94 for QGS and 0.90 for 4D-MSPECT). QGS significantly (P < 0.0001) underestimated LVEF, whereas no other parameter differ...
The objective was to assess visibility and anatomy of the petromastoid canal in high-resolution C... more The objective was to assess visibility and anatomy of the petromastoid canal in high-resolution CT. Computed tomography images of 188 patients were reviewed for delineation of the petromastoid canal. This bony canal connects the mastoid antrum with the cranial cavity and houses the subarcuate artery and vein. The diameter, obtained in the middle portion of the canal, was compared with the diameter of the vestibular and cochlear aqueduct in all patients, and absolute values measured in 20 cases. Collimation was 1 mm in 164 and 2 mm in 24 examinations. Additionally, temporal bone of a cadaver was imaged and microdissected. The petromastoid canal was identified bilaterally in all 164 scans that were obtained with a slice thickness of 1 mm. In 5 of the 24 patients imaged with a collimation of 2 mm, the canal was not visible, most probably due to partial-volume effects. The petromastoid canal had the same diameter as the cochlear aqueduct in 42/44 (right/left), exceeded it in 66/61 and w...
2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC), 2009
I. INTRODUCTION PET/MR has started gaining more interest recently because of its obvious advantag... more I. INTRODUCTION PET/MR has started gaining more interest recently because of its obvious advantages over PET/CT: firstly MRI offers much better soft-tissue contrast; secondly it does not cause patients' exposure to extra radiation dose. However, it is technically very ...
Nonalcoholic fatty liver disease has been linked to cardiovascular diseases and atherosclerosis. ... more Nonalcoholic fatty liver disease has been linked to cardiovascular diseases and atherosclerosis. The aim of the current study was to characterize the hepatic pathology leading to fibrosis and tumors in a murine model of atherosclerosis. Male apolipoprotein E/low-density lipoprotein receptor double-knockout mice (AL) mice were fed with a high fat and high cholesterol western diet for 35 weeks (AL mice on WD). Protein and mRNA analysis as well as micro-computed tomography (micro-CT) were performed to assess oxidative stress, liver damage, inflammation, fibrosis, signaling pathways, vascularization, and tumorigenesis. Controls were chosen to distinguish between genetically and dietary effects in steatohepatitis and associated tumorigenesis. Hepatic inflammation and dyslipidemia were increased in AL mice on WD compared with wild-type mice on WD. Uniquely, AL mice on WD showed a spontaneous development of tumors (30% of cases) and thickening of intrahepatic vessel walls. Functionally relevant underlying signaling pathways such as NF-κB, Stat3, JNK, and AKT were differentially regulated between AL and wild-type mice on WD. Micro-CT was capable of visualizing and quantitatively distinguishing tumor neovascularization from vascularization in non-neoplastic liver tissue. AL mice on WD diet represent a novel model combining atherosclerosis and nonalcoholic fatty liver disease. Signaling pathways of liver cell damage and compensatory liver regeneration in combination with enhanced inflammation appear to be crucial for the spontaneous development of tumors in AL mice on WD. Micro-CT represents a new and powerful technique for the ultrastructural and three-dimensional assessment of the vascular architecture of liver tumors.
CT- and MR-Guided Interventions in Radiology, 2009
Osteoid osteoma is a benign bone tumor which was first described by Jaffe (1935). Histologically ... more Osteoid osteoma is a benign bone tumor which was first described by Jaffe (1935). Histologically it consists of a centrally located nidus composed of osteoblasts and osteoid which is surrounded by an area of reactive sclerosis and/or periosteal new bone formation. Prostaglandins which are produced by the tumor induce a chronic inflammatory reaction and vasodilatation which results in stimulation of
To assess the value of different image reconstruction algorithms for assessment of the left ventr... more To assess the value of different image reconstruction algorithms for assessment of the left ventricular function using retrospectively ECG-gated multislice spiral computed tomography (MSCT) of the heart. MSCT and cine magnetic resonance (MR) imaging of the heart were performed in 15 patients. For MSCT, standard and multisegmental image reconstruction with improved temporal resolution were used. Standardized multiplanar reformats in the short axis and long axis views were reconstructed from MSCT data. End-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF) and myocardial mass (MM) were calculated. Left ventricular wall motion was assessed qualitatively. MSCT was in acceptable agreement with MR imaging for quantification of the ventricular function. According to the Bland-Altman approach the mean differences for the left ventricular volumes (ESV, EDV, SV) ranged from -9.6 ml to 3.1 ml with standard image reconstruction and from -0.6 ml to 1.9 ml utilizing multisegmental image reconstruction with limits of agreement ranging from -26.6 ml to 12.5 ml and -15.6 ml to 15.0 ml, respectively. Applying the multisegmental image reconstruction algorithm, a significantly improved agreement with the MR data was found for EDV, SV and EF. For wall motion analysis, standard image reconstruction showed a significant difference to MR imaging with a correspondence in 83.75% of the 240 assessed segments, while multisegmental image reconstruction agreed with MR imaging in 92.5% of the segments. Multisegmental image reconstruction improves the quantitative assessment of left ventricular function when compared to standard image reconstruction. Multisegmental image reconstruction allows qualitative wall motion analysis.
Nicorandil is an adenosine triphosphate-sensitive potassium channel opener with a nitrate-like ef... more Nicorandil is an adenosine triphosphate-sensitive potassium channel opener with a nitrate-like effect. It is approved for clinical use in Europe and Japan as an antianginal drug. The purpose of this investigation was to assess the acute effects of nicorandil therapy on microvascular injury using the blood pool MR contrast medium, NC100150 injection (Clariscan). Microvascular injury was produced in 24 rats using 45 min of coronary occlusion / 3 hr reperfusion. Nicorandil was infused at 15 min of occlusion and during reperfusion. Control animals received a saline solution. MR imaging was used to characterize microvascular permeability, quantify the extent of microvascular injury, LV volume, and wall thickness. Hyperenhancement at 30 min after administration of 0.05 mmol/kg Clariscan mapped the extent of ischemia-induced loss of microvascular integrity. The accumulation of Clariscan in the injured region was significantly suppressed in nicorandil compared to control rats. Nicorandil reduced the extent of microvascular injury from 44 +/- 2% to 18 +/- 2% (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) and true infarction size from 29 +/- 2% to 12 +/- 1%. The extent of the hyperenhanced region correlated with the true size of area at risk at autopsy. On spin-echo MRI during end-diastole, nicorandil reduced LV end-diastolic volume and preserved wall thickness in remote myocardium; both parameters are markers of LV dilatation caused by acute infarction (remodeling). In conclusion, blood pool contrast-enhanced MRI has the potential to depict and quantify the extent of microvascular permeability and injury. Nicorandil suppressed microvascular permeability, reduced infarction size, and improved LV function in early postinfarction reperfusion.
To assess the feasibility of using magnetic resonance (MR) imaging to guide stent deployment in t... more To assess the feasibility of using magnetic resonance (MR) imaging to guide stent deployment in the pulmonary valve and artery and evaluate, after stent deployment, the position and morphology of and blood flow through the stent. Angiography and 1.5-T MR imaging were performed in a dual-imaging suite. Nitinol stents were placed in the pulmonary valve and main pulmonary artery in five pigs by using MR imaging guidance. For interactive MR imaging monitoring of catheter manipulation and stent delivery, balanced fast field-echo and T1-weighted turbo field-echo sequences were used. Visualization of the delivery system was based on T2* (with air as the contrast material) or T1 (with gadodiamide as the contrast material). After stent deployment, the position and morphology of and flow through the stent were verified with multiphase multisection balanced fast field-echo and velocity-encoded cine MR imaging. Findings at angiography and postmortem examination also helped verify stent placement. The paired Student t test was used for data analysis. The stent was successfully deployed in all animals. The stent was placed distal to the pulmonary valve in four animals and across the pulmonary valve in one animal. The position and morphology of the stent were clearly depicted on balanced fast field-echo images. In the animal with the stent placed across the pulmonary valve, the pulmonary regurgitant fraction was 37%; this was not seen in the animals with stents placed distal to the pulmonary valve. No complication (eg, stent migration, intramural injury, or vascular perforation) was noted during the intervention. Findings at angiography and postmortem examination confirmed the position of the stents. MR imaging has the potential to guide stent placement in the pulmonary valve or artery and to evaluate flow volume within the stent lumen after the intervention.
PURPOSE: To demonstrate the feasibility of using a combination of x-ray fluoro- scopic and magnet... more PURPOSE: To demonstrate the feasibility of using a combination of x-ray fluoro- scopic and magnetic resonance (MR) fluoroscopic (ie, x-ray/MR fluoroscopy) guid- ance for left ventricular (LV) catheterization and transendocardial delivery of extra- cellular tissue markers. MATERIALS AND METHODS: Experiments were performed in six dogs by using an x-ray/MR fluoroscopy system. The arterial guide wire and catheter were ad- vanced
In the last decade, spiral computed tomography (CT) and magnetic resonance (MR) angiography (MRA)... more In the last decade, spiral computed tomography (CT) and magnetic resonance (MR) angiography (MRA) have become a viable alternative to conventional angiography in the diagnosis of acute pulmonary embolism. However, patients with dyspnea are often unable to hold their breath for a longer time and thus image degradation is frequently observed. Consequently, an imaging sequence that allows free breathing is desirable. The aim of this animal study was to compare contrast-enhanced spiral CT, MRA and a real-time MR sequence, the latter without breath-hold, with pulmonary angiography as reference gold standard. Nine pigs with artificially induced pulmonary embolism underwent this multimodality comparison. All images were independently evaluated for the presence of pulmonary emboli by two reviewers. Forty-three filling defects were detected by conventional angiography on lobar and segmental levels. Sensitivity of CT images was 72.1 and 69.8% for Readers 1 and 2, respectively, and sensitivity of MRA images was 79.1 and 81.4%. With real-time MR imaging, however, the detection rate was 97.7% for both readers. We conclude that, under experimental conditions, real-time MR imaging without the use of radiation or iodinated contrast material is comparable with angiography in the detection of pulmonary emboli.
The aim of the study was to compare, in patients with chronic ischaemic cardiomyopathy, contrast-... more The aim of the study was to compare, in patients with chronic ischaemic cardiomyopathy, contrast-enhanced cardiovascular magnetic resonance (ce-CMR) imaging and a combined (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and (99m)Tc-sestamibi single-photon emission computed tomography (SPECT) protocols for the prediction of functional recovery after revascularization, as assessed by cine CMR. Twenty-nine patients with ischaemic cardiomyopathy (ejection fraction 32 +/- 10%) were investigated with ce-CMR and PET/SPECT. For the assessment of global and regional functions, cine CMR was performed at baseline and at 6 months follow-up. For ce-CMR, the segmental extent of hyperenhancement (SEH) was quantitated, and for PET/SPECT, different viability categories were defined according to a validated quantitative protocol. Functional improvement was related to the SEH by ce-CMR, as well as to the viability categories by PET/SPECT. Sensitivity and specificity for the prediction of functional recovery at follow-up was 97 and 68% for ce-CMR and 87 and 76% for PET/SPECT. The positive predictive value was identical for both techniques (73%). However, ce-CMR achieved a higher negative predictive value (93 vs. 77%, respectively), indicating that ce-CMR may be superior to PET/SPECT for the identification of segments unlikely to recover function after revascularization. Both methods had a similar yield in the prediction of global functional improvement. ce-CMR is comparable with a PET/SPECT imaging protocol for the prediction of regional and global functional improvement after revascularization. However, ce-CMR may be superior to nuclear imaging for the identification of segments that are unlikely to recover function at follow-up.
Zusammenfassung Die Tuba Eustachii regelt Belüftung, Protektion und die Drainage des Mittelohrs. ... more Zusammenfassung Die Tuba Eustachii regelt Belüftung, Protektion und die Drainage des Mittelohrs. Funktionsstörungen treten überwiegend im Kindesalter auf. Folgen sind Otitis und Hörminderung. Der wichtigste Tubenmuskel ist der M. tensor veli palatini. Die Komplexität der funktionellen Anatomie und der Physiologie der Tuba auditiva führen dazu, dass kein Untersuchungsverfahren allein in der Lage ist, allen diagnostischen Erfordernissen gerecht zu werden. Der prädiktive
The prevalence of systemic atherosclerosis and overactive bladder/detrusor overactivity increases... more The prevalence of systemic atherosclerosis and overactive bladder/detrusor overactivity increases almost simultaneously with age but an association between these diseases has not yet been proved. We evaluated changes in bladder function and morphology, including vascularization, in apoE(-/-)LDLR(-/-) double knockout mice with systemic atherosclerosis but without central nervous system involvement. Cystometry was performed in awake, freely moving 60-week-old apoE(-/-)LDLR(-/-) mice and C57BL/6N controls. The mice were sacrificed and perfused with Microfil® contrast medium. The bladder was excised, dissected and scanned by nano-computerized tomography, including 3-dimensional reconstruction. Samples then underwent histomorphological analysis. In apoE(-/-)LDLR(-/-) mice cystometry revealed a significant decrease in the peak-peak interval, micturition interval, functional bladder capacity and micturition volume. However, maximum bladder pressure increased. Nano-computerized tomography r...
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2004
The aim of this study was to validate Quantitative Gated SPECT (QGS) and 4D-MSPECT for assessing ... more The aim of this study was to validate Quantitative Gated SPECT (QGS) and 4D-MSPECT for assessing left ventricular end-diastolic and systolic volumes (EDV and ESV, respectively) and left ventricular ejection fraction (LVEF) from gated (18)F-FDG PET. Forty-four patients with severe coronary artery disease were examined with gated (18)F-FDG PET (8 gates per cardiac cycle). EDV, ESV, and LVEF were calculated from gated (18)F-FDG PET using QGS and 4D-MSPECT. Within 2 d (median), cardiovascular cine MRI (cMRI) (20 gates per cardiac cycle) was done as a reference. QGS failed to accurately detect myocardial borders in 1 patient; 4D-MSPECT, in 2 patients. For the remaining 42 patients, correlation between the results of gated (18)F-FDG PET and cMRI was high for EDV (R = 0.94 for QGS and 0.94 for 4D-MSPECT), ESV (R = 0.95 for QGS and 0.95 for 4D-MSPECT), and LVEF (R = 0.94 for QGS and 0.90 for 4D-MSPECT). QGS significantly (P < 0.0001) underestimated LVEF, whereas no other parameter differ...
The objective was to assess visibility and anatomy of the petromastoid canal in high-resolution C... more The objective was to assess visibility and anatomy of the petromastoid canal in high-resolution CT. Computed tomography images of 188 patients were reviewed for delineation of the petromastoid canal. This bony canal connects the mastoid antrum with the cranial cavity and houses the subarcuate artery and vein. The diameter, obtained in the middle portion of the canal, was compared with the diameter of the vestibular and cochlear aqueduct in all patients, and absolute values measured in 20 cases. Collimation was 1 mm in 164 and 2 mm in 24 examinations. Additionally, temporal bone of a cadaver was imaged and microdissected. The petromastoid canal was identified bilaterally in all 164 scans that were obtained with a slice thickness of 1 mm. In 5 of the 24 patients imaged with a collimation of 2 mm, the canal was not visible, most probably due to partial-volume effects. The petromastoid canal had the same diameter as the cochlear aqueduct in 42/44 (right/left), exceeded it in 66/61 and w...
2009 IEEE Nuclear Science Symposium Conference Record (NSS/MIC), 2009
I. INTRODUCTION PET/MR has started gaining more interest recently because of its obvious advantag... more I. INTRODUCTION PET/MR has started gaining more interest recently because of its obvious advantages over PET/CT: firstly MRI offers much better soft-tissue contrast; secondly it does not cause patients' exposure to extra radiation dose. However, it is technically very ...
Nonalcoholic fatty liver disease has been linked to cardiovascular diseases and atherosclerosis. ... more Nonalcoholic fatty liver disease has been linked to cardiovascular diseases and atherosclerosis. The aim of the current study was to characterize the hepatic pathology leading to fibrosis and tumors in a murine model of atherosclerosis. Male apolipoprotein E/low-density lipoprotein receptor double-knockout mice (AL) mice were fed with a high fat and high cholesterol western diet for 35 weeks (AL mice on WD). Protein and mRNA analysis as well as micro-computed tomography (micro-CT) were performed to assess oxidative stress, liver damage, inflammation, fibrosis, signaling pathways, vascularization, and tumorigenesis. Controls were chosen to distinguish between genetically and dietary effects in steatohepatitis and associated tumorigenesis. Hepatic inflammation and dyslipidemia were increased in AL mice on WD compared with wild-type mice on WD. Uniquely, AL mice on WD showed a spontaneous development of tumors (30% of cases) and thickening of intrahepatic vessel walls. Functionally relevant underlying signaling pathways such as NF-κB, Stat3, JNK, and AKT were differentially regulated between AL and wild-type mice on WD. Micro-CT was capable of visualizing and quantitatively distinguishing tumor neovascularization from vascularization in non-neoplastic liver tissue. AL mice on WD diet represent a novel model combining atherosclerosis and nonalcoholic fatty liver disease. Signaling pathways of liver cell damage and compensatory liver regeneration in combination with enhanced inflammation appear to be crucial for the spontaneous development of tumors in AL mice on WD. Micro-CT represents a new and powerful technique for the ultrastructural and three-dimensional assessment of the vascular architecture of liver tumors.
CT- and MR-Guided Interventions in Radiology, 2009
Osteoid osteoma is a benign bone tumor which was first described by Jaffe (1935). Histologically ... more Osteoid osteoma is a benign bone tumor which was first described by Jaffe (1935). Histologically it consists of a centrally located nidus composed of osteoblasts and osteoid which is surrounded by an area of reactive sclerosis and/or periosteal new bone formation. Prostaglandins which are produced by the tumor induce a chronic inflammatory reaction and vasodilatation which results in stimulation of
To assess the value of different image reconstruction algorithms for assessment of the left ventr... more To assess the value of different image reconstruction algorithms for assessment of the left ventricular function using retrospectively ECG-gated multislice spiral computed tomography (MSCT) of the heart. MSCT and cine magnetic resonance (MR) imaging of the heart were performed in 15 patients. For MSCT, standard and multisegmental image reconstruction with improved temporal resolution were used. Standardized multiplanar reformats in the short axis and long axis views were reconstructed from MSCT data. End-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF) and myocardial mass (MM) were calculated. Left ventricular wall motion was assessed qualitatively. MSCT was in acceptable agreement with MR imaging for quantification of the ventricular function. According to the Bland-Altman approach the mean differences for the left ventricular volumes (ESV, EDV, SV) ranged from -9.6 ml to 3.1 ml with standard image reconstruction and from -0.6 ml to 1.9 ml utilizing multisegmental image reconstruction with limits of agreement ranging from -26.6 ml to 12.5 ml and -15.6 ml to 15.0 ml, respectively. Applying the multisegmental image reconstruction algorithm, a significantly improved agreement with the MR data was found for EDV, SV and EF. For wall motion analysis, standard image reconstruction showed a significant difference to MR imaging with a correspondence in 83.75% of the 240 assessed segments, while multisegmental image reconstruction agreed with MR imaging in 92.5% of the segments. Multisegmental image reconstruction improves the quantitative assessment of left ventricular function when compared to standard image reconstruction. Multisegmental image reconstruction allows qualitative wall motion analysis.
Nicorandil is an adenosine triphosphate-sensitive potassium channel opener with a nitrate-like ef... more Nicorandil is an adenosine triphosphate-sensitive potassium channel opener with a nitrate-like effect. It is approved for clinical use in Europe and Japan as an antianginal drug. The purpose of this investigation was to assess the acute effects of nicorandil therapy on microvascular injury using the blood pool MR contrast medium, NC100150 injection (Clariscan). Microvascular injury was produced in 24 rats using 45 min of coronary occlusion / 3 hr reperfusion. Nicorandil was infused at 15 min of occlusion and during reperfusion. Control animals received a saline solution. MR imaging was used to characterize microvascular permeability, quantify the extent of microvascular injury, LV volume, and wall thickness. Hyperenhancement at 30 min after administration of 0.05 mmol/kg Clariscan mapped the extent of ischemia-induced loss of microvascular integrity. The accumulation of Clariscan in the injured region was significantly suppressed in nicorandil compared to control rats. Nicorandil reduced the extent of microvascular injury from 44 +/- 2% to 18 +/- 2% (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) and true infarction size from 29 +/- 2% to 12 +/- 1%. The extent of the hyperenhanced region correlated with the true size of area at risk at autopsy. On spin-echo MRI during end-diastole, nicorandil reduced LV end-diastolic volume and preserved wall thickness in remote myocardium; both parameters are markers of LV dilatation caused by acute infarction (remodeling). In conclusion, blood pool contrast-enhanced MRI has the potential to depict and quantify the extent of microvascular permeability and injury. Nicorandil suppressed microvascular permeability, reduced infarction size, and improved LV function in early postinfarction reperfusion.
To assess the feasibility of using magnetic resonance (MR) imaging to guide stent deployment in t... more To assess the feasibility of using magnetic resonance (MR) imaging to guide stent deployment in the pulmonary valve and artery and evaluate, after stent deployment, the position and morphology of and blood flow through the stent. Angiography and 1.5-T MR imaging were performed in a dual-imaging suite. Nitinol stents were placed in the pulmonary valve and main pulmonary artery in five pigs by using MR imaging guidance. For interactive MR imaging monitoring of catheter manipulation and stent delivery, balanced fast field-echo and T1-weighted turbo field-echo sequences were used. Visualization of the delivery system was based on T2* (with air as the contrast material) or T1 (with gadodiamide as the contrast material). After stent deployment, the position and morphology of and flow through the stent were verified with multiphase multisection balanced fast field-echo and velocity-encoded cine MR imaging. Findings at angiography and postmortem examination also helped verify stent placement. The paired Student t test was used for data analysis. The stent was successfully deployed in all animals. The stent was placed distal to the pulmonary valve in four animals and across the pulmonary valve in one animal. The position and morphology of the stent were clearly depicted on balanced fast field-echo images. In the animal with the stent placed across the pulmonary valve, the pulmonary regurgitant fraction was 37%; this was not seen in the animals with stents placed distal to the pulmonary valve. No complication (eg, stent migration, intramural injury, or vascular perforation) was noted during the intervention. Findings at angiography and postmortem examination confirmed the position of the stents. MR imaging has the potential to guide stent placement in the pulmonary valve or artery and to evaluate flow volume within the stent lumen after the intervention.
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