Magnetic resonance myocardial perfusion imaging-First experience at 3.0T.

OBJECTIVE: MR myocardial perfusion imaging (MRMPI) is an established technique for the evaluation of the hemodynamical relevance of coronary artery disease. Perfusion imaging at 3.0T provides certain advantages compared to 1.5T. Aim of this study was to evaluate myocardial MR perfusion imaging at 3.0T. MATERIALS AND METHODS: Twelve patients with stable Angina pectoris and known or suspected coronary artery disease were examined at 3.0T. Myocardial perfusion was assessed using a saturation recovery gradient echo 2D sequence (TR 1.9ms, TE 1.0ms, FA 12 degrees ) with 0.05mmol Gd-DTPA per kg body weight at stress during injection of 140microg adenosine/kg body weight/min and at rest in short axis orientation. Perfusion analysis was based on a least square fit of the signal/time curve (peak signal intensity, slope). Perfusion series were assessed by two independent observers. Reference for the presence of relevant coronary artery stenoses was invasive coronary angiography. Two experienced observers evaluated the coronary angiograms in biplane projections for the presence and grade of stenoses. Results were compared with the MR perfusion analysis. RESULTS: All MR examinations could be safely performed and yielded high image quality. In eight patients stress-induced hypoperfusion was detected (stenosis >70% in coronary angiography). In four patients myocardial hypoperfusion was ruled out (stenosis <70%). The myocardial perfusion reserve index was significantly reduced in hypoperfused myocardium with 1.9+/-1.6 compared to 2.5+/-1.6 in regularly perfused myocardium (p<0.05). In coronary angiography, eight patients were found to suffer from coronary artery disease, whereas in four patients coronary artery disease was ruled out. CONCLUSION: Our initial results show that MRMPI at 3.0T provides reliably high-image quality and diagnostic accuracy.

MRI assessment of cardiac amyloidosis: experience of six cases with review of the current literature.

Cardiac MRI is known to be diagnostically valuable in cardiac amyloidosis. Several features are frequently found, including myocardial hypertrophy, diastolic dysfunction, a faster gadolinium blood wash out, pleural and pericardial effusions, and diffuse myocardial delayed enhancement. Cardiac MR facilitates the detection of cardiac amyloidosis and allows longitudinal assessment of myocardial function. This pictorial review focuses on cases with histologically proven systemic amyloidosis and cardiac involvement in order to illustrate typical findings.

Assessment of coronary artery bypass grafts by magnetic resonance imaging.

This study evaluated graft patency and flow at rest/stress in patients with coronary artery bypass grafts using MR flow measurements and MR angiography (MRA). 45 symptomatic patients with 86 grafts (46 arterial, 40 venous) were examined 5.5 years after surgery. MRA was used to assess bypass patency. Flow measurements were performed at rest and after stress induction with dipyridamole. All graft segments were evaluated at MRA for stenosis, and were additionally evaluated by the combination of flow measurements and MRA. Conventional coronary angiography or multidetector computed tomography was regarded as a reference standard. No significant stenosis was observed in 49 grafts (Group A), whereas significant stenosis was observed in 37 grafts (Group B). Sensitivity, specificity, and positive and negative predictive values for stenosis in arterial grafts were 95.2%, 96.8%, 80% and 99.4%, respectively, and in venous grafts were 100%, 97.8%, 87.5% and 100%, respectively. The mean blood flow rate at baseline/stress in Group B was significantly lower than that in Group A (p<0.002/p<0.001). With the combined MR method, 84 of 86 (97%) grafts could be correctly classified. In conclusion, MRI allows a combined assessment of graft status, including bypass patency and flow, in symptomatic patients after revascularization.

1 M Gd-chelate (gadobutrol) for multislice first-pass magnetic resonance myocardial perfusion imaging.

The aim of the study was to evaluate a 1 M gadolinium-chelate (gadobutrol) for first-pass MR myocardial perfusion examinations in patients with suspected coronary artery disease (CAD). In phantom studies, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) values of gadobutrol were compared with gadopentetate (Gd-DTPA). 25 consecutive patients with clinically suspected CAD were examined with dynamic rest/stress MR perfusion examinations using 0.05 mmol kg(-1) gadobutrol. Semi-quantitative evaluation of the myocardial perfusion was performed by calculating the myocardial perfusion reserve index (MPRI). Hypoperfused regions were correlated with data from X-ray coronary angiography. In phantom studies, SNR/CNR of gadobutrol-doped blood samples were consistently higher for all applied flip angles at concentrations < or =1.0 mmol L(-1) compared with Gd-DTPA. Assessment of 81 stress perfusion series with gadobutrol in 25 patients yielded a sensitivity of 82% and specificity of 91% for significant CAD. Combining the information from all perfusion series of one patient yielded a sensitivity of 89% and specificity of 94% on a per-vessel basis. Gadobutrol exhibited favourable signal properties in phantom studies. Rest/stress myocardial perfusion examinations using 1 M gadobutrol yielded high sensitivity and specificity in detection of malperfused areas (82% and 91%, respectively). This is comparable with recently published perfusion data using 0.5 M Gd-DTPA.

[Cardiovascular whole-body MR imaging in patients with symptomatic peripheral arterial occlusive disease]. / Kardiovaskuläre MR-Ganzkörperbildgebung bei Patienten mit symptomatischer Atherosklerose der peripheren Gefässe.

PURPOSE: To examine patients with peripheral-arterial-occlusive-disease (PAOD) for systemic effects associated with atherosclerosis using a comprehensive state-of-the-art whole-body MR examination protocol. The protocol comprises the assessment of the complete arterial vasculature (except coronary arteries), the brain, and the heart. MATERIALS AND METHODS: Multi-station whole-body 3D MR angiography was performed in sixty consecutive patients with clinical suspicion for PAOD at 1.5 T (Magnetom Avanto, Siemens, Erlangen, Germany). Functional and delayed enhancement cardiac images were acquired, as well as FLAIR images of the brain and TOF angiography of intracranial vessels. MR and DSA images were assessed by independent observers for atherosclerotic manifestations and other pathology. Sensitivity and specificity for the detection of vascular pathology was calculated for MR data using conventional DSA of the symptomatic region as standard-of-reference. RESULTS: Sensitivity and specificity for the detection of significant vascular stenosis (> 70 % luminal narrowing) was 94 % and 96 % (PPV 87 %, NPV 98 %). Significant microangiopathic tissue alterations (n = 7) and/or cerebral infarction (n = 18) were diagnosed in 23/60 patients. Thirty-eight of 60 patients presented with systolic left ventricular wall motion abnormalities. In 24 patients subendocardial or transmural delayed enhancement was detected in corresponding regions, indicating prior myocardial infarction. CONCLUSION: For patients with PAOD and suspected systemic atherosclerotic disease a comprehensive diagnosis of accompanying cardiovascular pathology and therefore staging of systemic atherosclerotic disease is feasible within one MR examination.

[MR angiography and determination of the flow reserve after minimal invasive direct coronary artery bypass (MIDCAB) surgery of the left internal mammary artery in comparison to multirow CT]. / MR-Angiographie und Flussreservenbestimmung nach minimalinvasiver direkter Koronararterien-Bypass(MIDCAB)-Operation der linken Arteria mammaria interna im Vergleich zur Mehrzeilen-CT.

PURPOSE: To evaluate graft patency, flow and flow reserve in patients with minimal invasive direct coronary artery bypass (MIDCAB) of internal mammary artery (IMA) grafts using a combined MR protocol with phase-contrast technique and MR angiography. MATERIAL AND METHODS: At a 1.5T Magnetom Sonata (SIEMENS), 19 symptomatic (angina CCS I-III, intermittent thoracic discomfort, scar disorders) patients (59.9 +/- 7.9 years old) with 19 left internal mammary artery (LIMA) grafts implanted in minimal invasive technique were examined 6.9 +/- 1.5 years post surgery. Contrast enhanced MR angiography (TR 2.5 ms, TE 1 ms, flip angle 20 (o), spatial resolution 1.4 x 0.9 x 1.0 mm(3), breath hold technique, no ECG-triggering, 25 ml Gd-DTPA) was performed to assess bypass patency. Phase-contrast flow measurements with retrospective gating (TR 41 msec, TE 3.2 msec, flip angle 30 degrees , spatial resolution 1.1 x 1.1 x 5 mm(3), temporal resolution 42 msec, venc 90 cm/sec) were applied in the IMA grafts at rest and after stress induction with dipyridamole (0.56 mg/kg/BW). For comparison, graft patency was evaluated by multidetector-row computed tomography (16-row CT). In 9 patients a selective catheter angiography was performed. RESULTS: MIDCAB grafts were occluded in 4/19 patients. In 4 patients the anastomosis to LAD was highly stenotic (> 70 %) at MDCT (2 experienced investigators in consensus reading). In MRA 9 grafts could be delineated completely including the distal anastomosis to LAD (47 %). In 9 patients the distal part could not be evaluated. In patients with patent grafts (MDCT), a significant improvement of graft flow (at rest 75.4 +/- 33.3 ml/min; after stress 202.7 +/- 49.6; P < 0.002) and flow reserve (patent grafts 3.0 +/- 1.1; stenotic grafts 1.5 +/- 0.2, P < 0.02; occluded grafts 0.9 +/- 0.2, P < 0.01) after stress induction was detected. Diastolic-to-systolic peak velocity ratios (D/S-PVR) at baseline were not significant between patent and stenotic grafts. Mean flow at baseline and after stress induction and flow reserve show a high sensitivity (91/92 /83 %) and specificity (86 /100/83 %) for detection of graft stenosis. MR angiography combined with flow reserve measurements could distinguish between occluded/stenotic and patent grafts in all MIDCAB grafts. CONCLUSION: MR imaging allows combined assessment of bypass patency and flow with flow reserve in patients after MIDCAB. The protocol of this study is applicable for the evaluation of graft patency in patients after revascularization.

Perioperative monitoring of flow and patency in native and grafted internal mammary arteries using a combined MR protocol.

The objective of this study was to evaluate graft flow (f) and patency (p) in patients with internal mammary artery (f,p) and venous (p only) grafts using a combined MR protocol with phase-contrast technique and MR angiography. 42 patients with 42 left internal mammary artery (LIMA) and 63 venous grafts were examined pre and 6 months post coronary artery bypass graft (CABG) surgery. Phase-contrast flow measurements were applied to the IMA. Post-operatively, a contrast enhanced MR angiogram was performed to assess bypass patency. LIMA/venous grafts were occluded in 3/42 and 13/63, respectively. Flow in LIMA decreased from 19.4+/-10.4 ml min(-1) m(-2) pre-operatively to 13.4+/-9.7 ml min(-1) m(-2) post-operatively (p<0.002). In contrast, flow in the native right IMA increased from 17.6+/-8.7 ml min(-1) m(-2) pre-operatively to 24.8+/-9.0 ml min(-1) m(-2) post-operatively (p<0.001). MRI allows a combined assessment of bypass patency and flow. This study protocol may be applicable to perioperative follow-up studies in patients after CABG surgery.

[Left ventricular functional parameters: comparison of 16-slice spiral CT with MRI]. / Bestimmung linksventrikulärer Funktionsparameter: Vergleich von 16-Zeilen-Mehrschicht-CT mit der MR-Tomographie.

PURPOSE: The quantitative measurement of left ventricular functional parameters using multislice computed tomography (MSCT) with retrospective ECG-gating and comparison of the results with magnetic resonance imaging (MRI). MATERIALS AND METHODS: Thirty-one patients with suspected or known coronary artery disease underwent MSCT angiography with retrospective ECG-gating (Sensation 16, Siemens). Based on the CT data set, short axis reformations of the left ventricle were performed for functional analysis. On a commercially available workstation, end-diastolic- (EDV), end-systolic- (ESV), stroke volume (SV), ejection fraction (EF) and myocardial mass (MM) were calculated from MSCT (temporal resolution 105 - 210 ms) data according to the modified Simpson's rule and compared to MRI (1.5 T scanner, temporal resolution 48 ms) using a 2D TrueFISP cine sequence with respiration hold. RESULTS: In all cases, the quality was adequate for both MSCT and MRI. MSCT and MRI had an excellent correlation for EDV (r = 0.86), ESV (r = 0.91), EF (r = 0.87) and MM (r = 0.88), and a good correlation for SV (r = 0.70). The mean difference was 13.2 +/- 21.9 ml for EDV, 8.7 +/- 15.9 ml for ESV, 4.6 +/- 12.3 ml for SV, 1.4 +/- 5.2 % for EF, and 11.9 +/- 13.8 g for MM. However, EDV (p = 0.002), ESV (p = 0.005), SV (p = 0.048), and MM (p < 0.0001) were significantly overestimated with MSCT compared to MRI. For EF, no significant difference between MSCT and MRI was found (p = 0.15). CONCLUSION: For left ventricular functional parameters, MSCT of the heart with retrospective ECG-gating showed a high correlation with MRI, which has an important implication when using MSCT for non-invasive cardiac imaging. Despite the high correlation, overestimation of EDV, EVS, SV, and MM with MSCT has to be taken into account when applying this technology in clinical practice. EF was not significantly different between both modalities.

[TrueFISP MR imaging to determine the influence of hemodialysis on the myocardial functional parameters in patients with terminal renal insufficiency]. / TrueFISP-MR-Bildgebung zur Bestimmung des Einflusses der Hämodialyse auf myokardiale Funktionsparameter bei Patienten mit terminaler Niereninsuffizienz.

PURPOSE: To assess the characteristic signs of uremic cardiomyopathy in patients with chronic renal failure (CRF) in comparison with healthy volunteers and to determine changes of left ventricular (LV) functional parameters in patients undergoing hemo-dialysis (HD). METHODS AND MATERIALS: Using a 1.5 T Magnetom Sonata system (Siemens, Erlangen), cardiac MR imaging was performed on 26 patients (20 men, 6 women, mean age 54.7 years) and 14 volunteers (8 men, 6 women, mean age 27.7 years). Single-slice true FISP sequences (TR 3.2 ms, TE 1.6 ms, flip angel 58 degrees, matrix 256 x 208, slice thickness 5 mm) were used to obtain contiguous short axis slices covering the whole left ventricle. Patients were examined before and immediately after HD. Cardiodynamic parameters [end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), myocardial mass (MM), cardiac output (CO)] were calculated using the modified Simpson's rule (Argus Software, Siemens). Patient data were compared to reference values taken from healthy volunteers. RESULTS: As a consequence of HD, significant differences (p < 0.01) were observed for EDV (150 + 47 ml/114 + 49 ml), ESV (71 + 46 ml/60 + 56 ml), SV (79 + 25 ml/57 + 27 ml) and CO (3.6 + 1.0 l/min*m (2)/2.6 + 1.1 l/min*m (2)). Although EF (56 + 15 %/53 + 18 %) was decreased after HD, values did not differ significantly (p > 0.05). MM (148 + 47 g/148 + 52 g) and myocardial mass index (80.7 +/- 27.4 g/m (2)/80.1 +/- 9.1 g/m (2)) did not change before and after HD. In all patients, signs of LV-hypertrophy (LVH) and increased CO were diagnosed compared to reference values. In 8 of 26 patients, additional pathology, such as valvular dysfunction or global cardiac insufficiency, was detected. CONCLUSION: Cardiac MRI is an accurate tool to identify uremic cardiomyopathy in patients with chronic renal failure undergoing HD. LV functional parameters could be monitored reliably.

[Multislice TrueFISP-MR imaging for identifying stress-induced myocardial functional disturbances in coronary heart disease]. / Multislice TrueFISP-MR-Bildgebung zur Erkennung stressinduzierter myokardialer Funktionsstörungen bei koronarer Herzerkrankung.

PURPOSE: This study assesses the left ventricular function using a new multislice cine sequence and determines the diagnostic accuracy of stress-induced wall motion abnormalities in patients with coronary artery disease (CAD). MATERIALS AND METHODS: 15 patients (mean age 57.7 years) with angiographically proven CAD were examined on a 1.5 T whole body system (Magnetom Sonata, Siemens, Erlangen) at rest and during dipyridamole-induced (0.56 mg/kg body weight) stress. Left ventricular function was determined using a multislice (steady-state) sequence (TR 2.3 ms, TE 1.15 ms, slice thickness 10 mm, temporal resolution 77 ms) as well as a standard single-slice true FISP 2D sequence (TR 3.2 ms, TE 1.6 ms, slice thickness 5 mm, temporal resolution 45 ms) as reference. RESULTS: Both cine sequences provide high sensitivity and excellent correlation (r = 0.95) with angiographic findings for the detection of regional wall motion abnormalities. However, the measurement of functional parameters yielded significant differences. End-systolic left ventricular volumes (ESV) were systematically overestimated in the multislice images (mean 78 ml, + 5.8 %) compared with the reference single-slice images (mean 74 ml) (p < 0.05). This resulted in underestimation of the ejection fraction with multislice images (mean 40 %, - 11.3 %) compared with single-slice images (mean 46 %) (p < 0.05). CONCLUSION: The multislice sequence results in a substantial reduction of imaging time and breath-hold periods necessary to cover the left ventricle for functional assessment. The multislice sequence yields adequate images, especially for qualitative determination of wall motion abnormalities. Due to the reduced spatial and temporal resolution of the multi-slice sequence, however, some uncertainty concerning the functional parameters has to be taken into account.

[2D-phase contrast flow evaluation and contrast-enhanced MR angiography for perioperative assessment of internal mammary artery grafts]. / 2D-Phasenkontrast-Flussquantifizierung und kontrastangehobene 3D-MR-Angiographie zur perioperativen Untersuchung des Arteria-mammaria-interna-Bypasses.

PURPOSE: To evaluate LV functional parameters, graft flow and patency in patients with IMA grafts using a combined MR protocol with phase-contrast technique and contrast enhanced MR angiography. MATERIAL AND METHODS: Using a 1.5 T MR system 27 patients with 27 left internal mammary artery (LIMA) and 41 venous grafts were examined before and 6 months after CABG surgery. A T(1)w-TSE sequence (slice thickness 5 mm) was applied for morphological imaging. LV function (EF, CO) was evaluated on cine images (segmented FLASH 2D, TR(eff) 11 ms, TE 4.8 ms, flip angle 25 degrees ). A phase-contrast FLASH 2D (TR 24 ms, TE 5 ms, flip angle 20 degrees ) sequence was applied for aortic and IMA flow measurements. Postoperatively, a contrast enhanced FLASH 3D MR angiography (TR 3.8 ms, TE 1.4 ms, flip angle 30 degrees ) with 25 ml Gd-DTPA was performed to assess bypass patency. RESULTS: In patients with reduced LV function (ejection fraction < 50 %) an improvement of the ejection fraction from 38.4 +/- 10.3 % to 49.8 +/- 15.3 % (p < 0.05) was found postoperatively. LIMA grafts were occluded in 1/27 patients, while 6/41 venous grafts were occluded. Distal LIMA anastomoses were demonstrated in 33 % by MRA. Flow of LIMA decreased from 21.2 +/- 11 ml/min/m(2) preoperatively to 14.4 +/- 9.6 ml/min/m(2) postoperatively (p < 0.01). CONCLUSION: MR imaging allows accurate combined assessment of LV function, bypass patency and flow. The protocol of this study may be applicable for perioperative follow-up studies in patients after CABG surgery.

Subacute myocardial infarction: assessment by STIR T2-weighted MR imaging in comparison to regional function.

PURPOSE: Increased T2 signal intensity (SI) can be regularly observed in myocardial infarction. However, there are controversial reports about the relationship of elevated T2 SI to myocardial viability and some authors propose that high T2 SI serves as a sign of irreversible myocardial injury. This study investigates increased T2 SI compared to myocardial function in patients with reperfused subacute myocardial infarction. Preserved function was used as criterion for viability. METHODS: Ten healthy volunteers and 17 patients with myocardial infarction and patent infarct related coronary artery were examined on a 1.5 T Magnetom Vision system (Siemens). For T2-weighted MR imaging a breath-hold STIR sequence with dark-blood preparation was used. Cine FLASH 2D imaging was applied to assess myocardial function. Signal-to-noise (S/N) in STIR T2 images was measured in normal and infarcted regions and subsequently identified by two independent observers. Based on a 20 segment model of the left ventricle findings were compared to regional myocardial function. RESULTS: Elevated STIR T2 SI was found in all 17 patients and observed in 27% (204/754) of segments. S/N of normal myocardium was 5.1 +/- 0.7 in volunteers and 4.9 +/- 0.8 in patients (P = NS). Infarcted myocardium presented with significantly increased S/N 12.8 +/- 1.9 (P < 0.0001). Significant transmural elevation of T2 SI was noted in 32% of segments with preserved systolic function. CONCLUSION: Increased STIR T2 SI can be observed transmurally in post-ischemic myocardial regions with preserved function. It therefore cannot be used as an exclusive marker for the non-viable region.

MRI diagnosis of a previously undiagnosed large trabecular ventricular septal defect in an adult after multiple catheterizations and angiocardiograms.

Ventricular septal defect (VSD) is the most frequent congenital heart disease (25-30%). The diagnosis of VSD is usually made echocardiographically by means of colour Doppler ultrasound, and is confirmed by angiocardiography in most cases. We describe a case in which an additional large trabecular VSD was demonstrated by MRI after previous cardiac catheterizations and angiocardiography in various hospitals. MRI allows an exact presentation of the anatomy, including areas that are difficult to assess, for instance the apical septum. Determination of cardiac output, regurgitation volume and the Qp/Qs quotient in patients with shunt volume in heart defects is also possible with one examination.

Fat- and water-selective MR cine imaging of the human heart: assessment of right ventricular dysplasia.

RATIONALE AND OBJECTIVES: The purpose of this study was to develop and implement MR sequences for chemical shift-selective breath-hold cine imaging of the heart. Fibroadipose conversion of myocardium in cases suspected of right ventricular dysplasia should be revealed in fat- and water-selective MR images of high quality. METHODS: Frequency-selective saturation of one chemical shift component was applied in modified k-space-segmented, electrocardiography-gated sequences, allowing high-quality cine imaging of the human heart in a single breath-hold. Phantom studies and human examinations in eight normal subjects (aged 24-62 years) and in seven patients (aged 31-47 years) with suspected right ventricular dysplasia were performed. The patients showed suspicious findings, such as a dyskinetic and dilated right ventricle combined with ventricular arrhythmia, and underwent MR imaging after exclusion of other possible reasons (eg, coronary artery disease or pulmonary hypertension). RESULTS: High selectivity to the desired chemical shift component was confirmed by test measurements in a phantom containing water and lipids. In the human subjects, minor problems with magnetic field inhomogeneities appeared in the thoracic walls only. Four patients with suspected right ventricular dysplasia showed clearly abnormal signal behavior of the right myocardial wall in both fat- and water-selective cine images. Bright transmural structures were exhibited in fat-selective images, but the origin of the fat (epicardium or infiltrated myocardium) was often difficult to assess. CONCLUSIONS: Right ventricular areas with fibrosis and fatty degeneration often show normal signal intensity in standard T1-weighted images but can be differentiated from normal tissue by the new chemical shift-selective breath-hold cine techniques.

MR angiography and flow quantification of the internal mammary artery graft after minimally invasive direct coronary artery bypass.

OBJECTIVE: Six patients who had undergone minimally invasive direct coronary artery bypass surgery were examined to evaluate an MR imaging protocol that provided information about cardiac function, bypass graft patency, and flow characteristics with a single examination. CONCLUSION: Preliminary results suggest that our imaging protocol allows accurate follow-up of patients after minimally invasive direct coronary artery bypass surgery. Bypass graft patency was correctly determined in all patients. In four patients, anastomoses were visualized by MR angiography, and flow measurements revealed a volume range of 28-84 ml/min (native and grafted internal mammary arteries) and a trend for the flow values of bypass grafts to be lower than those of native vessels. Interobserver reproducibility was good (r = .99; slope, .98).

[Optimization of numerical measurement parameters for ECG-triggered MRI snapshot-FLASH myocardial perfusion studies]. / Numerische Messparameteroptimierung für EKG-getriggerte MR Snapshot-FLASH Myokardperfusionsuntersuchungen.

BACKGROUND AND AIMS: In MR examinations of myocardial perfusion by the use of Snapshot-FLASH sequences it is of major importance that the achievable signal difference between pre- and normal postcontrast myocardium be maximized. METHODS: In ECG-triggered Snapshot-FLASH sequences the signal intensity of the myocardium depends on the flip angle alpha, the inversion time TI and the trigger delay TD (both depending on the cardiac frequency f) for unchanged slice thickness (SL), matrix size (MA), repetition time (TR) and echo time (TE). Therefore a simulation of the signal behavior of pre- and postcontrast myocardium based on Bloch's equations was performed by varying the flip angle alpha, TI and TD for different cardiac frequencies in order to determine an optimized combination of the measurement parameters. RESULTS: In normal heart rates (50-70 beats/min) maximal signal differences between pre- and normal postcontrast myocardium can be reached for inversion times TI = 170-200 ms and a flip angle alpha = 11 degrees. For higher heart rates again alpha = 11 degrees and TI = 200-220 ms with shortened TD (TD = 0 for f > 90 beats/min) were found to be optimal. The calculated values were semiquantitatively confirmed in phantom and volunteer measurements. CONCLUSIONS: The described method allows cardiac frequency dependent optimization of the Snapshot-FLASH measurement parameters alpha, TI and TD in order to reach a maximum in signal contrast between normal and malperfused myocardium.