First-pass Perfusion Sequence Research Articles

Novel implementation of cardiac magnetic resonance first-pass perfusion imaging for semi-quantitatively evaluating microvascular dysfunction in paediatric patients with Duchenne muscular dystrophy.

The current study aimed to assess myocardial microcirculation dysfunction via cardiac magnetic resonance (CMR) first-pass perfusion imaging in children with Duchenne muscular dystrophy (DMD). In total, 67 children with DMD and 15 controls who underwent contrast-enhanced CMR first-pass perfusion imaging were enrolled in this study. CMR first-pass perfusion and late gadolinium enhancement (LGE) sequences were acquired. Further, the global, regional, and coronary artery distribution area perfusion indexes (PI), upslope (%BL), maximum signal intensity (MaxSI), time to maximum signal intensity (TTM), and baseline SI were analysed. The perfusion parameters of the LGE positive (+), LGE negative (-), and control groups were compared. Pearson correlation analysis was performed to assess the association between myocardial microcirculation and conventional cardiac function and LGE parameters. The LGE+ group had a significantly lower global and apical-ventricular MaxSI than the control group (all P < .05). The left anterior descending arterial (LAD), left circumflex coronary arterial (LCX), and right coronary arterial (RCA) segments of the LGE+ group had a lower upslope and MaxSI than those of the control group (all P < .05). The LAD segments of the LGE- group had a lower MaxSI than those of the control group (41.10 ± 11.08 vs 46.36 ± 13.04; P < .001). The LCX segments of the LGE- group had a lower PI and upslope than those of the control group (11.05 ± 2.84 vs 12.46 ± 2.82; P = .001; 59.31 ± 26.76 vs 68.57 ± 29.99; P = .002). Based on the correlation analysis, the upslope, MaxSI, and TTM were correlated with conventional cardiac function and LGE extent. Paediatric patients with DMD may present with microvascular dysfunction. This condition may appear before LGE and may be correlated with coronary artery blood supply and LGE extent. First-pass perfusion parameters may reveal the status of myocardial microcirculation and reflect the degree of myocardial injury at an earlier time in DMD patients. Perfusion parameters should be analysed not only via global or base, middle, and apical segments but also according to coronary artery distribution area, which may detect myocardial microvascular dysfunction at an earlier stage, in DMD patients with LGE-.

809 A CASE OF CASEOUS MITRAL ANNULUS CALCIFICATION

Abstract Caseous mitral annular calcification (CMAC) is a rare variant of degenerative mitral annular calcification (MAC) with an echocardiographic prevalence of 0.6% of all MACs and an overall prevalence of up to 0.07% in the general population. It primarily affects older patients with hypertension and chronic kidney disease. Due to the general benign prognosis, conservative management of this lesion is recommended in most cases. Herein we describe the case of a 78-year-old female patient admitted for sustained ventricular tachycardia treated with Amiodaron infusion followed by electrical cardioversion for hemodynamically instability. Her past medical history was remarkable for hypertension, HFpEF and chronic kidney disease. Trans-thoracic echocardiogram showed the presence of an echo-dense mass with central echo-lucency surrounded by calcifications at the posterior peri-annular and leaflet region of the mitral valve, not associated with valvular disfunction. To define the etiology of the arrythmia, a coronary angiography was performed and excluded significant coronary artery disease. Nevertheless, a round-shape hyperdense mass was observed in the left atrium near the atrio-ventricular groove (figure 1): during injection through coronary vessels the contrast was not visible in the lesion. In order to better define the nature of the mass, a Trans-esophageal Echocardiogram was performed and showed a “toothpaste-like” echo-dense mass with central echo-lucency surrounded by a calcified envelope at the posterior peri-annular region of the mitral valve suggestive for CMAC (figure 2); 3D zoom imaging clarified its relationship with P2 scallop of posterior mitral valve leaflet (figure 3). For the best tissue characterization and to definitely exclude other mass-like lesions, such as myxoma, papillary fibroelastoma, myocardial abscess, vegetations, lipomatous hypertrophy, Cardiac Magnetic Resonance was performed and showed low-signal intensity in both T1- and T2-weighted sequences, reflecting its calcium content. First-pass perfusion sequence reveals no contrast enhancement, whereas late gadolinium enhancement depicts a peripheral rim of enhancement confirming our suspect. In Conclusion, CMAC is a rare disorder requiring a multimodal imaging approach to differentiate it with other intra-cardiac masses. Its course is generally benign and whether not associated with valvular or hemodynamic significance, it could be considered as a bystander. Figure 1 Figure 2 Figure 3

A papillary fibroelastoma with myxoma camouflage: a case report

BackgroundBenign cardiac tumours are infrequent in clinical practice and, of these, cardiac myxoma is the one with the highest incidence. Given that a left intraventricular presentation is rare, other differential diagnoses such as papillary fibroelastoma should be considered.Case summaryA 73-year-old woman patient with cardiac mass detected in transthoracic echocardiography (TTE) after a transient ischaemic attack. At TTE 2D–3D, a left intraventricular mass anchored at the level of the anterolateral papillary muscle was detected. Subsequently, cardiac magnetic resonance (CMR) was performed for mass characterization. This revealed behaviour in T1 (isointense with respect to myocardium), T2 (hyperintense), very prolonged T1-mapping (1848 msg), and T2-mapping (161 msg) values, without gadolinium uptake in the first-pass perfusion sequence, but with intense uptake in late enhancement sequences. Previous findings were compatible with a diagnosis of papillary fibroelastoma. The mass was resected intraoperatively and, although its macroscopic appearance pointed to a diagnosis of cardiac myxoma, it was finally confirmed to be a papillary fibroelastoma by pathological anatomy.DiscussionIn cases where the size of the mass and its mobility allow tissue characterization by CMR, a diagnosis of papillary fibroelastoma and its differentiation with cardiac myxoma are feasible by this cardiac imaging technique.

An MRI Image Analysis of Primary Cardiac Neoplasms.

ObjectiveThis study aimed to examine the magnetic resonance imaging (MRI) characteristics of primary cardiac neoplastic lesions.MethodsA retrospective investigation was conducted on 24 cases of primary cardiac neoplastic lesions as confirmed by surgery and pathology results. All the cases in this study received MRI multi-sequence and multi-dimension scanning, including the cardiac long-axis and short-axis cine sequences, parameter sequences of the cardiac long axis and short axis (T1WI, T2WI), first-pass perfusion sequence, and delayed enhancement sequence of the cardiac long axis and short axis. The age and gender of the patients and the location, size, signal characteristics, and relationship with the neighboring tissues of all the lesions were examined.ResultsTwenty-four cases of primary neoplastic lesions were examined in this study, the onset age was 11–72 years old, the median age was 53 years old, and the mean age was 46 years old. Among these cases, there were 8 cases including males and 16 cases including females, 19 cases were benign lesions; including 11 cases of myxoma, 4 cases of hemangioma, 1 case of paraganglioma, 1 case of PEcoma, 1 case of hamartoma, and 1 case of lipoma. The malignant lesions included 3 sarcomas and 2 lymphomas in 5 patients.ConclusionMRI imaging provides a great value in the preoperative classification of primary cardiac neoplastic lesions.

Differential and prognostic value of cardiovascular magnetic resonance derived scoring algorithm in cardiac tumors

ObjectivesTo establish a scoring algorithm based on cardiovascular magnetic resonance (CMR) parameters for differentiating between benign and malignant cardiac tumors and for predicting outcome. MethodsPatients referred for CMR for suspected cardiac tumors were prospectively enrolled. Tumors were categorized as benign or malignant based on pathology, imaging, and clinical information. The CMR protocol included cine, T1-weighted, T2-weighted, first-pass perfusion, and late gadolinium enhancement (LGE) sequences. Variables independently associated with malignancy in the multivariable logistic analysis were used to construct the scoring algorithm, and receiver operating characteristic analyses were used to assess the ability to discriminate malignant from benign tumors. The ability of the score to predict outcome (all-cause mortality) was also assessed by Kaplan–Meier survival analysis. ResultsAmong the 105 enrolled patients, 74 had benign and 31 had malignant tumors. In multivariable analysis, the independent predictors of malignant tumors were invasiveness (odds ratio, OR = 11.4, 2 points), irregular border (OR = 5.8, 1 point), and heterogenous LGE (OR 10.6, 2 points). The area under curves (AUC) of the scoring algorithm was 0.912 (cut-off score of 5) and showed significantly higher AUCs than individual variables (all P < 0.05) in differentiating benign and malignant tumors. After median follow-up of 18.2 months, mortality was significantly higher in patients with a score of 5 than in patients with score ≤ 4. ConclusionsThe scoring algorithm based on CMR-detected invasiveness, irregularity of border, and heterogenous LGE is an effective method for differentiating malignant from benign cardiac tumors and for predicting outcome.

Initial investigation of free-breathing 3D whole-heart stress myocardial perfusion MRI.

Objective: Myocardial first-pass perfusion imaging with MRI is well-established clinically. However, it is potentially weakened by limited myocardial coverage compared to nuclear medicine. Clinical evaluations of whole-heart MRI perfusion by 3D methods, while promising, have to date had the limit of breathhold requirements at stress. This work aims to develop a new free-breathing 3D myocardial perfusion method, and to test its performance in a small patient population.Methods: This work required tolerance to respiratory motion for stress investigations, and therefore employed a “stack-of-stars” hybrid Cartesian-radial MRI acquisition method. The MRI sequence was highly optimised for rapid acquisition and combined with a compressed sensing reconstruction. Stress and rest datasets were acquired in four healthy volunteers, and in six patients with coronary artery disease (CAD), which were compared against clinical reference information.Results: This free-breathing method produced datasets that appeared consistent with clinical reference data in detecting moderate-to-strong induced perfusion abnormalities. However, the majority of the mild defects identified clinically were not detected by the method, potentially due to the presence of transient myocardial artefacts present in the images.Discussion: The feasibility of detecting CAD using this 3D first-pass perfusion sequence during free-breathing is demonstrated. Good agreement on typical moderate-to-strong CAD cases is promising, however, questions still remain on the sensitivity of the technique to milder cases.

306 - First-pass perfusion imaging to improve the assessment of left ventricular thrombus following a myocardial infarction

Abstract Purpose To assess whether a first-pass perfusion sequence (FPP) improved the detection of left ventricular thrombus (LVT). Materials and methods Three hundred and twenty-nine patients with a first STEMI were prospectively included to undergo cardiac magnetic resonance (CMR) at baseline and after a 3-month follow-up. A CMR delayed analysis was performed by three blinded examiners (2 CMR experts and 1 novice) according to a two-step reading protocol. First, an analysis was performed on cine CMR and late gadolinium enhancement (routine stage). Then, the FPP stage was performed following initial protocol along with a FPP sequence. Results LVT was found in 31 out of a total of 638 (4.9%) CMR scans, affecting 30 (9.1%) individuals. All were located in the left ventricular apex. The FPP stage improved significantly the LVT diagnosis for all readers, in 10 and 13 cases (32% and 42%) of LVT suspicion for the experts and 16 cases (41%) for the novice. Respectively 1, 2 and 6 LVT were not detected during the routine stage by the CMR experts and the novice. For the novice, the FPP stage improved diagnosis sensitivity from 78.1 to 91.2%. Conclusions The prevalence of LVT following a myocardial infarction reached 9.1% and increased with the reading of FPP sequence. The FPP stage improved expert diagnostic certitude and the novice’s abilities to reach expert level.

First pass perfusion imaging to improve the assessment of left ventricular thrombus following a myocardial infarction

PurposeTo assess whether a first-pass perfusion sequence (FPP) improved the detection of left ventricular thrombus (LVT). Materials and methodsThree hundred and twenty-nine patients with a first STEMI were prospectively included to undergo cardiac magnetic resonance (CMR) at baseline and after a 3-month follow-up. A CMR delayed analysis was performed by three blinded examiners (2 CMR experts and 1 novice) according to a two-step reading protocol. First, an analysis was performed on cine CMR and late gadolinium enhancement (routine stage). Then, the FPP stage was performed following initial protocol along with a FPP sequence. ResultsLVT was found in 31 out of a total of 638 (4.9%) CMR scans, affecting 30 (9.1%) individuals. All were located in the left ventricular apex. The FPP stage improved significantly the LVT diagnosis for all readers, in 10 and 13 cases (32% and 42%) of LVT suspicion for the experts and 16 cases (41%) for the novice. Respectively 1, 2 and 6 LVT were not detected during the routine stage by the CMR experts and the novice. For the novice, the FPP stage improved diagnosis sensitivity from 78.1 to 91.2%. ConclusionsThe prevalence of LVT following a myocardial infarction reached 9.1% and increased with the reading of FPP sequence. The FPP stage improved expert diagnostic certitude and the novice’s abilities to reach expert level.

0083 : Hyperhemia on the first-pass MRI perfusion for the diagnosis of acute myocarditis

MRI is the current way for the diagnosis of acute myocarditis, based on the Lake Louise criteria (presence of at least two of the three following criteria: myocardial edema, hyperaemia and/or a late Gadolinium enhancement). The first-pass perfusion sequence, used for detecting myocardial ischemia, may also be used to highlight a myocardial hyperemia in acute myocarditis. The aim of our study was to assess subepicardial hyperemia, seen on the first pass perfusion sequence by MRI, as a new method for the diagnosis of acute myocarditis. 47 patients (mean age = 42.4±15,6 years; 35 men) with acute myocarditis were included and compared to 16 healthy controls (without heart disease). The first-pass perfusion was evaluated by two blinded observers and compared to myocardial late Gadolinium enhancement, considered the reference method for the diagnosis of acute myocarditis, using both a qualitative (visual analysis) and a semi-quantitative method (ratio of the signals: infarction hyperaemia / healthy myocardium). 24 (51.1%) patients with myocarditis exhibited detectable hyperemia. Qualitative analysis showed good inter-observer variability (kappa = 0.75). There was an increase of the signal intensity in the myocardium with hyperhemia as compared to the adjacent normal myocardium (myocarditis vs controls: 1.08±0.03 vs 0.95±0.05, p=0.03; myocarditis with hyperhemia vs myocarditis non hyperhemia: 1.22±0.04 vs 0.94 ±0.04, p<0.0001). The correlation between the first-pass perfusion and late Gadolinium enhancement was good (kappa = 0,70). Considering the late Gadolinium enhancement as gold standard, the calculated values of sensitivity and specificity were 85% and 94%, respectively. Hyperhemia on the First-pass perfusion sequence, is a valuable and reproducible tool for the diagnosis of acute myocarditis. The author hereby declares no conflict of interest

An extended 3D whole-heart myocardial first-pass perfusion sequence: alternate-cycle views with isotropic and high-resolution imaging

Background Simultaneously optimising parameters such as LV coverage, image resolution and contrast sensitivity is difficult in first-pass perfusion (FPP). 3D FPP shows potential (1) to improve coverage, but “whole-heart” coverage demands high acceleration forcing compromises such as loss of spatial resolution. 2D FPP shows high diagnostic ability with more slices distributed over alternate-RR cycles (2), relaxing acceleration requirements. This work proposes that 3D FPP could interleave two strategies with different 3D parameters in alternate cycles, in sum approaching the full set of desired FPP properties. This work also aims to improve specificity against artefacts by imaging the same myocardium with two different interleaved 3D scans (distinct from reformatting a single 3D FPP scan). Similar confirmation strategies are often used in CMR, such as repetition with swapped phaseencode direction in late-enhancement imaging.

Cardiovascular MR imaging at 3 T: opportunities, challenges, and solutions.

Although 3-T magnetic resonance (MR) imaging is well established in neuroradiology and musculoskeletal imaging, it is in the nascent stages in cardiovascular imaging applications, and there is limited literature on this topic. The primary advantage of 3 T over 1.5 T is a higher signal-to-noise ratio (SNR), which can be used as such or traded off to improve spatial or temporal resolution and decrease acquisition time. However, the actual gain in SNR is limited by other factors and modifications in sequences adapted for use at 3 T. Higher resonance frequencies result in improved spectral resolution, which is beneficial for fat suppression and spectroscopy. The higher T1 values of tissues at 3 T aid in myocardial tagging, angiography, and perfusion and delayed-enhancement sequences. However, there are substantial challenges with 3-T cardiac MR imaging, including higher magnetic field and radiofrequency inhomogeneities and susceptibility effects, which diminish image quality. Off-resonance artifacts are particularly challenging, especially with steady-state free precession sequences. These artifacts can be managed by using higher-order shimming, frequency scouts, or low repetition times. B1 inhomogeneities can be managed by using radiofrequency shimming, multitransmit coils, or adiabatic pulses. Chemical shifts are also increased at 3 T. The higher radiofrequency results in higher radiofrequency deposition power and a higher specific absorption rate. MR angiography, dynamic first-pass perfusion sequences, myocardial tagging, and MR spectroscopy are more effective at 3 T, whereas delayed-enhancement, flow quantification, and black-blood sequences are comparable at 1.5 T and 3 T. Knowledge of the relevant physics helps in identifying artifacts and modifying sequences to optimize image quality. Online supplemental material is available for this article.

Motion-corrected compressed-sensing enables robust spiral first-pass perfusion imaging with whole heart coverage

Background First-pass perfusion imaging using CMR is an important tool for diagnosing coronary artery disease (CAD), but most clinical techniques are limited in their spatial coverage. While compressed-sensing (CS) holds promise for highly accelerated perfusion spiral imaging, CS techniques suffer from blurring artifacts in the setting of respiratory motion. Spiral pulse sequences have multiple advantages for myocardial perfusion imaging including high acquisition efficiency, high signal to noise (SNR) and robustness to motion and for CS including a relatively incoherent aliasing pattern. Thus, we develop a whole heart spiral first-pass perfusion sequence combined with robust motion-correction.

Visualization of a Small Ventricular Septal Defect at First-pass Contrast-enhanced Cardiac Magnetic Resonance Imaging

Ventricular septal defect (VSD) is a congenital heart disease that accounts for up to 40% of all congenital cardiac malformations. VSD is a connection between right and left ventricle, through the ventricular septum. Echocardiography and magnetic resonance imaging (MRI) help identify this entity. This case presents a 12-year-old male diagnosed with a small muscular apical VSD of 3 mm in diameter, at echocardiography. Cardiac MRI using first-pass perfusion sequence, combining the right plane of acquisition with a short bolus of contrast material, clearly confirmed the presence of VSD.

Perfusion magnetic resonance imaging: Comparison of semiologic characteristics in first-pass perfusion of brain tumors at 1.5 and 3 Tesla

To investigate whether using 3 Tesla (T) instead of 1.5T modifies the data obtained from first-pass perfusion in relation to the quantitative values of cerebral blood volume (CBV) and estimation of micro-vascular leakage (MVL). To describe the differences in data in the setting of neuro-oncology cases and propose explanations based on the discrepancies. In total, 21 patients presenting an intracranial intra-axial space-occupying lesion underwent two MRI explorations, one at 1.5T and another at 3T, including a first-pass perfusion sequence using sequence parameters, defined by the manufacturer Philips. Using a gamma variate analysis, the ratio of cerebral blood volume (rCBV) in tumor, peritumoral, and normal appearing areas was first assessed. After a global analysis, a subgroup analysis was conducted according to the rCBV value measured at 1.5T. Lastly, MVL was assessed based on the signal intensity recorded above baseline after the passage of the contrast medium. At 3T, compared to 1.5T data that are currently the reference, rCBV was constantly and significantly over-evaluated (P=0.0041 for all tumors), while MVL was constantly and significantly under-evaluated (P<0.0001 for all tumors). The increase in magnetic field strength along with the associated modifications in sequence parameters led to variations in rCBV and MVL when measured using first-pass perfusion. In some cases, such as lymphomas, there was a loss of diagnostic information. It therefore appears necessary to optimize the acquisition parameters to allow for radiologic semiology to become relevant again.

Mouse myocardial first‐pass perfusion MR imaging

A first-pass myocardial perfusion sequence for mouse cardiac MRI is presented. A segmented ECG-triggered acquisition combined with parallel imaging acceleration was used to capture the first pass of a Gd-DTPA bolus through the mouse heart with a temporal resolution of 300-400 msec. The method was applied in healthy mice (N = 5) and in mice with permanent occlusion of the left coronary artery (N = 6). Baseline semiquantitative perfusion values of healthy myocardium showed excellent reproducibility. Infarct regions revealed a significant decrease in the semiquantitative myocardial perfusion values (0.05 ± 0.02) compared to remote myocardium (0.20 ± 0.04). Myocardial areas of decreased perfusion correlated well to infarct areas identified on the delayed-enhancement scans. This protocol is a valuable addition to the mouse cardiac MRI toolbox for preclinical studies of ischemic heart disease.

The Use of Cardiovascular Magnetic Resonance in Acute Myocardial Infarction

Acute myocardial infarction (MI) results in reversible and irreversible injury to the myocardium, including stunning, edema, myocyte necrosis, and microvascular obstruction. Because of its unique tissue characterization capabilities, cardiovascular magnetic resonance provides a reliable means of visualizing and quantifying the extent of these injuries. Such characterization is readily achieved through a comprehensive examination including function, first-pass perfusion, T2 (edema), and late enhancement imaging sequences. This helps to predict the prognosis, assess the success of reperfusion, detect acute phase complications, localize the area of the acute event, and confirm the diagnosis in clinical scenarios with clinical presentations similar to that of acute MI. Finally, one emerging application is the role cardiovascular magnetic resonance (CMR) may play in detecting some infarcts very early on in their evolution. This article covers the established and emerging clinical applications of CMR in the settings of reperfused and nonreperfused infarcts and in acute myocardial ischemia, the step immediately preceding actual irreversible injury.

The Current and Emerging Role of Cardiovascular Magnetic Resonance Imaging in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy with substantial heterogeneity in phenotypic expression and clinical course. Traditionally, two-dimensional echocardiography has been the easiest and most reliable technique for establishing a diagnosis of HCM. However, cardiovascular magnetic resonance (CMR) has emerged as a novel, three-dimensional tomographic imaging technique, which provides high spatial and temporal resolution images of the heart in any plane and without ionizing radiation. As a result, CMR is particularly well suited to provide detailed characterization of the HCM phenotype, including precise assessment of the location and distribution of left ventricular (LV) wall thickening. In this regard, CMR can identify hypertrophy (particularly in the anterolateral free wall and apex), not well appreciated (or underestimated) by two-dimensional echocardiography, with important implications for diagnosis. CMR can also provide detailed characterization of other myocardial structures such as the papillary muscles, which may impact on preoperative management strategies for patients who are candidates for surgical myectomy. Furthermore, CMR enables an accurate assessment of total LV mass, a robust marker of the overall extent of hypertrophy, which may have implications for risk stratification. In addition, a subgroup of HCM patients have normal LV mass (with focal hypertrophy), suggesting that a limited extent of hypertrophy is consistent with a diagnosis of HCM. Finally, following the intravenous administration of gadolinium, first-pass perfusion sequences can identify myocardial perfusion abnormalities, while late gadolinium enhancement (LGE) sequences can characterize areas of myocardial fibrosis/scarring. LGE is associated with systolic dysfunction and likelihood for ventricular tachyarrhythmias on ambulatory Holter monitoring in patients with HCM. However, the precise clinical implications of myocardial perfusion abnormalities and LGE in HCM are still uncertain; this information may have important implications with regard to identifying HCM patients at risk of sudden death and adverse LV remodeling associated with systolic dysfunction. Therefore, at present, CMR provides important information impacting on diagnosis and clinical management strategies in patients with HCM and will likely have an expanding role in the evaluation of patients with this complex disease.

Assessment of Microvascular Obstruction and Prediction of Short-term Remodeling after Acute Myocardial Infarction: Cardiac MR Imaging Study

To evaluate which cardiac magnetic resonance (MR) imaging technique for detection of microvascular obstruction (MVO) best predicts left ventricular (LV) remodeling after acute myocardial infarction (MI). This study had local ethics committee approval; all patients gave written informed consent. Sixty-three patients with first acute MI, treated with primary stent placement and optimal medical therapy, underwent cine MR imaging at 4-7 days and at 4 months after MI. Presence of MVO was qualitatively evaluated at baseline by using three techniques: (a) a single-shot saturation-recovery gradient-echo first-pass perfusion sequence (early hypoenhancement), mean time, 1.09 minutes +/- 0.07 (standard deviation) after contrast material administration; (b) a three-dimensional segmented saturation-recovery gradient-echo sequence (intermediate hypoenhancement), mean time, 2.17 minutes +/- 0.26; and (c) a two-dimensional segmented inversion-recovery gradient-echo late gadolinium enhancement sequence (late hypoenhancement), mean time, 13.32 minutes +/- 1.26. Contrast-to-noise ratios (CNRs) were calculated from the signal-to-noise ratios of the infarcted myocardium and MVO areas. Univariable linear regression analysis was used to identify the predictive value of each MR imaging technique. Early hypoenhancement was detected in 44 (70%) of 63 patients; intermediate hypoenhancement, in 39 (62%); and late hypoenhancement, in 37 (59%). Late hypoenhancement was the strongest predictor of change in LV end-diastolic and end-systolic volumes over time (beta = 14.3, r = 0.40, P = .001 and beta = 11.3, r = 0.44, P < .001, respectively), whereas intermediate and late hypoenhancement had comparable predictive values of change in LV ejection fraction (beta = -3.1, r = -0.29, P = .02 and beta = -2.8, r = -0.27, P = .04, respectively). CNR corrected for spatial resolution was significantly superior for late enhancement compared with the other sequences (P < .001). By using cardiac MR imaging, late hypoenhancement is the best prognostic marker of LV remodeling, with highest CNR between the infarcted myocardium and MVO regions.

3-Tesla MRI for the evaluation of myocardial viability: a comparative study with 1.5-Tesla MRI

We compared 3-Tesla (3-T) and 1.5-Tesla (1.5-T) cardiac magnetic resonance imaging (MRI) for the assessment of myocardial viability in nearly identical experimental conditions. Thirty-five patients (mean age 63+/-11; 94.2% men) submitted to primary coronary angioplasty underwent both 3-T and 1.5-T cardiac MRI, which was considered the gold standard. Comparison was performed on the basis of the same viability imaging protocol, which included resting cine-MR [balanced fast-field echo (B-FFE) sequence] followed by contrast-enhanced MR to evaluate perfusion and delayed enhancement (DE). We then performed functional index measurements and visual estimation of kinesis, perfusion and DE referring to a 5-point scale. Image quality was assessed on the basis of signal to noise ratio (SNR) and contrast to noise ratio (CNR). We found nonsignificant differences between the two scanners (P=NS) in measuring the functional and viability parameters. Myocardial SNR was significantly higher with 3-T MRI compared with 1.5-T MRI (61.3% gain). Even though a loss of CNR was recorded in B-FFE and in first-pass perfusion sequences (12.4% and 23.7%, respectively), on DE images, we quantified the increase of SNR and CNR of infarction of 387.8% and 330%, respectively. We found that 3-T MRI showed high concordance with 1.5-T MRI in the evaluation of functional and viability parameters and provided better evidence of damaged myocardium.

Detection of cardiac small vessel disease by adenosine-stress magnetic resonance

Background Patients testing positive for myocardial ischemia but without significant coronary artery (CA) stenosis in coronary angiography (CXA) are characterized as having “small vessel disease” (SVD). The aim of our study was to identify these patients by stress perfusion cardiac magnetic resonance (CMR). Methods 317 patients with suspected myocardial ischemia and clinical indication for CXA were scanned < 72 h before CXA in a whole-body 1.5T scanner. After 3 min of adenosine infusion (140 μg/kg/min), a myocardial first-pass perfusion sequence in 4–5 contiguous short-axis orientations using a Gadolinium-based contrast agent (0.1 mmol/kg) was performed. Images were analyzed qualitatively by two independent and blinded investigators. Results Perfusion deficits were detected in 93% of our patients. In 78% of patients with relevant perfusion delay, perfusion deficits extended to > 1/3 of the wall thickness in ≥ 2 myocardial segments, persisted for > 5 heartbeats and were regarded as relevant coronary macroangiopathy. All of these patients had significant CA stenosis (60% had luminal narrowing > 70% and 18% had 50–70%). 22% of the patients had perfusion deficits affecting ≤ 1/3 of wall thickness with persistence for ≤ 5 heartbeats and were regarded as having SVD. None of these patients had a CA stenosis of > 50% or received CA revascularization. These patients more frequently had hypertension ( p < 0.0001), diabetes ( p < 0.05) and circumferential perfusion deficits ( p < 0.0001) than other patients. Conclusion Stress perfusion CMR allows non-invasive differentiation between patients with significant CA stenosis and patients with SVD caused by hypertension and/or diabetes based on the temporal and spatial extent of perfusion deficits. Patients with SVD more often have diffuse perfusion deficits with shorter persistence than patients with significant CA disease.