Acute versus Chronic Myocardial Infarction: Diagnostic Accuracy of Quantitative Native T1 and T2 Mapping versus Assessment of Edema on Standard T2-weighted Cardiovascular MR Images for Differentiation.

Purpose To analyze the diagnostic accuracy of native T1 and T2 mapping compared with visual and quantitative assessment of edema on T2-weighted cardiac magnetic resonance (MR) images to differentiate between acute and chronic myocardial infarction. Materials and Methods This study had institutional ethics committee approval. Written informed consent was obtained from 67 consecutive patients (57 years ± 12; 78% men) with a first acute myocardial infarction, who were prospectively enrolled between April 2011 and June 2015. Four serial 1.5-T MR imaging examinations were performed at 8 days ± 5, 7 weeks ± 2, 3 months ± 0.5, and 6 months ± 1.4 after infarction and included T2-weighted, native T1/T2 mapping, and late gadolinium enhancement MR imaging. Complete follow-up data were obtained in 42 patients. Regional native T1/T2 relaxation time, T2-weighted ratio, and extracellular volume were serially measured in infarcted and remote myocardium. Receiver operating characteristic (ROC) analysis was used to determine the diagnostic accuracy of the MR imaging parameters for discriminating between acute and chronic myocardial infarction. Results Native T1 of infarcted myocardium decreased from 1286 msec ± 99 at baseline to 1077 msec ± 50 at 6 months (P < .0001), whereas T2 decreased from 84 msec ± 10 to 58 msec ± 4 (P < .0001). The T2-weighted ratio decreased from 4.1 ± 1.0 to 2.4 ± 0.6 (P < .0001). Of all the MR imaging parameters obtained, native T1 and T2 yielded the best areas under the ROC curve (AUCs) of 0.975 and 0.979, respectively, for differentiating between acute and chronic myocardial infarction. Visual analysis of the presence of edema at standard T2-weighted cardiac MR imaging resulted in an inferior AUC of 0.863 (P < .01). Conclusion Native T1 and T2 of infarcted myocardium are excellent discriminators between acute and chronic myocardial infarction and are superior to all other MR imaging parameters. Online supplemental material is available for this article.

Assessment of Left Ventricular Enlargement at Multidetector Computed Tomography.

PURPOSE: Because left ventricular (LV) enlargement (LVE) is indicative of an array of cardiac pathologies, including cardiomyopathic, ischemic, and valvular heart diseases, it is important to recognize it early in the course of these diseases. The recognition of LVE on nongated contrast-enhanced computed tomography (CT) scans should be facilitated by the availability of a dimensional index. To our knowledge, no CT index of LVE has been proposed. Therefore, the study aimed to define whether the maximum LV diameter (LVd) measured on nongated multidetector computed tomography can identify LVE when referencing echocardiography as the diagnostic standard. MATERIALS AND METHODS: The patient population consisted of 438 consecutive patients who had a contrast-enhanced, nongated 16- or 64-detector CT of the chest for evaluation of pulmonary embolism or aortic dissection between January 2006 and March 2008. One hundred fifty-five patients in this group also had an echocardiogram within 2 months of the CT study. The maximum LV cavity size, septal to lateral wall dimension, was measured perpendicularly to the long axis of the left ventricle on the axial CT scans by 2 observers blinded to the echocardiography data.An receiver operating characteristic analysis was performed to identify a highly specific cutoff for the diagnosis of LVE on CT, using echocardiogram as the standard of reference. Interobserver agreement was assessed using Bland-Altman analysis. RESULTS: A total of 84 females and 71 males were evaluated (female to male ratio of 1.09). The mean age for the 155 patients was 58 years. Six percent of these patients had a diagnosis of LVE on 2-dimensional echocardiography. The mean (SEM) LV internal diameter at nongated multidetector computed tomography between the group with normal LV and the group with LVE by echocardiography was 4.4 (0.7) cm for the normal LV and 5.9 (1.2) cm for the dilated LVs (P < 0.0001). With the use of threshold value of LVd of 5.6 cm, a sensitivity of 78%, specificity of 100%, positive likelihood ratio of 113.5, and negative likelihood ratio of 0.22 were calculated. The LVd measurements had an excellent agreement between observers on the Bland-Altman analysis. CONCLUSIONS: Left ventricular enlargement can be reliably identified on nongated contrast-enhanced multidetector CT when the maximum luminal diameter of the LV is greater than 5.6 cm. Nongated contrast-enhanced CT scan can be used to recognize LVE.

Advances in MR imaging assessment of adults with congenital heart disease.

Many novel cardiac MR sequences can be used for assessment of adult patients with congenital heart disease. Although most of these techniques are still primarily used in the research arena, there are many potential applications in clinical practice. Advanced cardiac MR assessment of myocardial tissue characterization, flow hemodynamics, and myocardial strain are promising tools for diagnostic and prognostic assessment late after repair of congenital heart diseases.

Cardiac radiology: centenary review.

During the past century, cardiac imaging technologies have revolutionized the diagnosis and treatment of acquired and congenital heart disease. Many important contributions to the field of cardiac imaging were initially reported in Radiology. The field developed from the early stages of cardiac imaging, including the use of coronary x-ray angiography and roentgen kymography, to nowadays the widely used echocardiographic, nuclear medicine, cardiac computed tomographic (CT), and magnetic resonance (MR) applications. It is surprising how many of these techniques were not recognized for their potential during their early inception. Some techniques were described in the literature but required many years to enter the clinical arena and presently continue to expand in terms of clinical application. The application of various CT and MR contrast agents for the diagnosis of myocardial ischemia is a case in point, as the utility of contrast agents continues to expand the noninvasive characterization of myocardium. The history of cardiac imaging has included a continuous process of advances in our understanding of the anatomy and physiology of the cardiovascular system, along with advances in imaging technology that continue to the present day.

Cardiovascular MR imaging after surgical correction of tetralogy of Fallot: approach based on understanding of surgical procedures.

Tetralogy of Fallot (TOF) is one of the most common congenital heart diseases for which patients are referred for postoperative magnetic resonance (MR) imaging evaluation. The most common surgical procedures for TOF repair include infundibulectomy, transannular pulmonary artery patch repair, and right ventricle-pulmonary artery conduit placement. In the past few decades, surgery has proved successful, but most patients require repeat imaging throughout their lives. MR imaging is now frequently used for morphologic and functional evaluation after TOF repair. The most common late postoperative sequelae and residual lesions include right ventricular outflow tract aneurysm and dyskinesis, conduit failure, pulmonary regurgitation, tricuspid regurgitation, right ventricular failure, residual main and branch pulmonary artery stenosis, branch pulmonary artery aneurysm, left pulmonary artery kinking, and residual or recurrent ventricular septal defect. The imaging approach for the evaluation of patients with repaired TOF should be guided by the surgical procedure used and the complications that are expected. Knowledge of the most common postoperative problems and their cardiovascular MR imaging appearances is essential for good radiology practice in this clinical setting.

CMR assessment of right ventricular function in patients with combined pulmonary stenosis and insufficiency after correction of tetralogy of Fallot.

BACKGROUND: Tetralogy of Fallot (TOF) is one of the most common types of congenital heart disease and requires prompt surgical correction. Post-correction pulmonary insufficiency (PI) often ensues in adulthood. At times, the PI is accompanied by residual pulmonary stenosis (PS). Little is known regarding right ventricular (RV) function in the setting of combined PS and PI. PURPOSE: To compare cardiac magnetic resonance (CMR) parameters for the assessment of RV function between patients with combined pulmonary stenosis and pulmonary insufficiency (PSPI) and isolated PI following surgical repair of TOF. MATERIAL AND METHODS: Retrospective review of patients with comparable corrected TOF and similar PI was performed. Seventeen patients (median age, 24 years; range, 10-52 years) had combined PSPI and 30 patients (median age, 30 years; range, 6-70 years) had isolated PI. Cine magnetic resonance (MR) images (Philips Medical Systems, Best, The Netherlands) in the short-axis plane were used to calculate end-systolic, end-diastolic, and stroke volumes (RVESV, RVEDV, RVSV) and to measure RV wall thickness. Velocity-encoded cine MR images were used to measure pulmonary regurgitation fraction (PRF) by calculating the ratio of backward flow and total forward flow, obtained from the main pulmonary flow analysis. Peak pressure gradient across the pulmonary valve was obtained from spectral Doppler echocardiography. RESULTS: RVEF was 51 ± 8% in the PSPI patients and 39 ± 11%, in the patients with isolated PI (P = 0.001). Additionally, RV wall thickness was 5.2 ± 0.8 mm in the PSPI patients compared to 2.6 ± 0.9 mm in the isolated PI patients (P = 0.001). RVESVi and RVEDVi were significantly lower (P < 0.05) in patients with combined PSPI (60 ± 21 mL/m(2), 121 ± 35 mL/m(2), respectively) compared to the patients with isolated PI (95 ± 48 mL/m(2), 152 ± 61 mL/m(2), respectively). CONCLUSION: RV function is preserved in patients with PSPI when compared to patients with PI following surgical repair of TOF.

Delayed enhancement magnetic resonance imaging in nonischemic myocardial disease.

This review highlights the role of delayed enhancement magnetic resonance imaging for the diagnosis of patients with nonischemic myocardial disease. The authors discuss the use of delayed enhancement for differentiation between ischemic and nonischemic myocardial disease and for narrowing the differential diagnosis when nonischemic etiologies are suspected. In addition, special focus is given to the prognostic applications of delayed enhancement magnetic resonance imaging.

Magnetic resonance imaging of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a genetically inherited disease with a wide spectrum of phenotypic presentations. It is crucial to establish an early diagnosis and identify patients at high risk for sudden death. Cardiac magnetic resonance can provide subclinical diagnosis, quantification of severity of known disease, risk stratification, and assessment of response to therapy for HCM. This pictorial review summarizes the main magnetic resonance appearances of HCM and its differential diagnosis.

Collateral flow measurement by phase-contrast magnetic resonance imaging for the assessment of systemic venous baffle patency after atrial switch repair for transposition of the great arteries.

PURPOSE: We aimed to describe and compare azygos vein flow patterns of patients with obstructed and unobstructed systemic venous baffle after atrial switch repair for d-transposition of the great arteries (TGA). We hypothesized that phase-contrast magnetic resonance imaging would enable characterization of retrograde collateral flow across the azygos vein in cases of systemic venous baffle obstruction. MATERIALS AND METHODS: This is a retrospective, cross-sectional study. Twelve patients with atrial switch repair for TGA were examined. Azygos flow index was measured with phase-contrast magnetic resonance imaging; comparison was made between patients with documented systemic venous baffle obstruction (n=3) and a control group of patients without baffle obstruction (n=9). RESULTS: Patients with systemic venous baffle obstruction had a distinctive azygos flow pattern that was retrograde and an increased amount of azygos flow compared with patients without obstruction [median (range), -436 (-455/-399) vs. 103 (51/125) mL/min/m2; P=0.01]. CONCLUSIONS: Patients with systemic venous baffle obstruction have a characteristic collateral flow across the azygos vein. Azygos vein flow measurement may be used for the assessment of baffle patency in patients after atrial switch repair for TGA. However, diagnostic accuracy needs to be tested in a larger population.

Impaired regional left ventricular strain after repair of tetralogy of Fallot.

PURPOSE: To test the potential of magnetic resonance imaging (MRI) in early detection of left ventricular (LV) dysfunction in patients with pulmonary regurgitation and normal LV ejection fraction after repair of tetralogy of Fallot. MATERIALS AND METHODS: Patients (n = 18) with repaired tetralogy of Fallot and pulmonary regurgitation were prospectively recruited. Healthy volunteers (n = 10) were used as control. Tagging MR images were acquired at the base, mid, and apical LV levels for assessing segmental rotation and circumferential strain. Cine MR images and velocity-encoded MR images were also acquired for assessment of biventricular volumes and biventricular function and pulmonary regurgitant fraction, respectively. Mean values were compared between groups using unpaired Student's t-test. RESULTS: Patients presented with preserved global LV function (LVEF of 59 ± 5%). A significant decrease in LV peak circumferential strain was seen in patients compared with normal volunteers at the basilar (-15.6 ± 4.5% vs. -17.6 ± 4.4%; P < 0.01) and apical (-14.4± 6.1% vs. -17.3± 5.1%, P < 0.01) slices. LV peak rotation was also delayed in patients compared with volunteers at the basilar (6.1 ± 2.6° vs. 4.2 ± 0.6°; P < 0.01) and mid (8.0 ± 1.7° vs. 4.9 ± 1.0°; P < 0.01) slices. CONCLUSION: MRI can detect early regional LV dysfunction in patients with preserved LVEF after repair of tetralogy of Fallot. MR may be a useful technique for guiding clinical decisions in these patients in order to prevent future global LV deterioration.

Heart as a source of stroke: imaging evaluation with computed tomography.

Stroke from cardiac sources is a major cause of cerebral infarctions and ischemia. Cardiac sources of stroke include intracardiac thrombus, right-to-left shunts, tumors, and slow-flow states resulting from hemodynamic compromise. Computed tomography angiography of the neck is currently used for the evaluation of a suspected stroke. The availability of longer multidetector computed tomography detector arrays and prospective echocardiography triggering techniques could permit evaluation of the chest, head, and neck during the same examination, streamlining patient evaluation and management.

Potential of delayed gadolinium enhancement magnetic resonance imaging for quantification of reverse remodeling of the peri-infarct zone in patients with ischemic cardiomyopathy treated with chronic vasodilator therapy: initial experience.

PURPOSE: The peri-infarct zone represents the morphologic substrate for reentry ventricular tachycardia after myocardial infarction, and its extent is a strong predictor of major cardiac events. Although delayed gadolinium enhancement magnetic resonance imaging (DGE-MRI) was shown to allow for detailed characterization of myocardial infarction by quantifying infarct core zone and peri-infarct zone volume, potentials of DGE-MRI for measuring changes in peri-infarct zone volume are unknown. Therefore, we aimed to assess changes in volume of the peri-infarct zone among patients with ischemic cardiomyopathy treated with chronic vasodilator therapy. MATERIALS AND METHODS: Core and peri-infarct zone volumes as assessed with DGE-MRI were measured in 5 patients at baseline and after 6 months treatment with sustained-release dipyridamole. RESULTS: Core zone volume remained stable during follow-up [median (range), 19 mL (9 to 42) vs. 16 mL (11 to 46); P=0.785]. The ratio between the peri-infarct zone and the core zone volume decreased significantly at 6 months compared with baseline [median (range), 0.22 (0.19 to 0.42) vs. 0.18 (0.09 to 0.32); P=0.043], and a trend toward reduction in peri-infarct zone volume was found [median (range), 5 mL (2 to 8) vs. 3 mL (2 to 6); P=0.059]. The peri-infarct zone volume decreased in all but 1 patient over the follow-up. CONCLUSIONS: This initial experience suggests that reverse remodeling of the peri-infarct zone with reduction in peri-infarct zone volume may take place in patients with ischemic cardiomyopathy. Quantification of this process may be feasible with DGE-MRI, but further studies are needed to confirm this hypothesis and to further clarify the role of DGE-MRI for the assessment of changes in peri-infarct zone volume in patients with ischemic cardiomyopathy.

Delayed contrast enhancement on MR images of myocardium: past, present, future.

Differential enhancement of myocardial infarction was first recognized on computed tomographic (CT) images obtained with iodinated contrast material in the late 1970s. Gadolinium enhancement of myocardial infarction was initially reported for T1-weighted magnetic resonance (MR) imaging in 1984. The introduction of an inversion-recovery gradient-echo MR sequence for accentuation of the contrast between normal and necrotic myocardium was the impetus for widespread clinical use for demonstrating the extent of myocardial infarction. This sequence has been called delayed-enhancement MR and MR viability imaging. The physiologic basis for differential enhancement of myocardial necrosis is the greater distribution volume of injured myocardium compared with that of normal myocardium. It is now recognized that delayed enhancement occurs in both acute and chronic (scar) infarctions and in an array of other myocardial processes that cause myocardial necrosis, infiltration, or fibrosis. These include myocarditis, hypertrophic cardiomyopathy, amyloidosis, sarcoidosis, and other myocardial conditions. In several of these diseases, the presence and extent of delayed enhancement has prognostic implications. Future applications of delayed enhancement with development of MR imaging and CT techniques will be discussed.

4D flow CMR in assessment of valve-related ascending aortic disease.

Blood flow imaging with 3-dimensional time-resolved, phase-contrast cardiac magnetic resonance (4-dimensional [4D] Flow) is an innovative and visually appealing method for studying cardiovascular disease that allows quantification of important secondary vascular parameters including wall shear stress. The hypothesis of this pilot study is that 4D Flow will become a powerful tool for characterizing the relationship of aortic valve-related flow dynamics, especially with bicuspid aortic valve (BAV), and progression of ascending aortic (AsAo) dilation. We identified 46 patients previously studied with 4D Flow: tricuspid aortic valve patients without valvular disease (n = 20), and BAV patients with either normal flow (n = 7) or eccentric systolic jets resulting in abnormal right-handed helical AsAo flow (n = 19). The subgroup of patients with BAV and eccentric systolic AsAo blood flow was found to have significantly and asymmetrically elevated wall shear stress. This increased hemodynamic burden may place them at risk for AsAo aneurysm.

Diagnostic value of the flow profile in the distal descending aorta by phase-contrast magnetic resonance for predicting severe coarctation of the aorta.

PURPOSE: To compare aortic flow profiles at the level of the proximal descending (PDAo) and distal descending aorta (DDAo) in patients investigated for coarctation of the aorta (CoA), and compare their respective diagnostic value for predicting severe CoA. Diastolic flow decay in the PDAo predicts severe CoA, but flow measurements at this level are limited by flow turbulence, aliasing, and stent-related artifacts. MATERIALS AND METHODS: We studied 49 patients evaluated for CoA with phase contrast magnetic resonance imaging (PC-MRI). Parameters of diastolic flow decay in the PDAo and DDAo were compared. Their respective diagnostic value was compared with the standard reference of transcatheter peak gradient ≥20 mmHg. RESULTS: Flow measurement in the PDAo required repeated acquisition with adjustment of encoding velocity or location of the imaging plane in 69% of patients; measurement in the DDAo was achieved in single acquisition in all cases. Parameters of diastolic flow decay in the PDAo and DDAo, including rate-corrected (RC) deceleration time and RC flow deceleration yielded a good correlation (r = 0.78; P < 0.01, and r = 0.92; P < 0.01), and a similar diagnostic value for predicting severe CoA. The highest diagnostic accuracy was achieved by RC deceleration time at DDAo (sensitivity 85%, specificity 85%). CONCLUSION: Characterization of aortic flow profiles at the DDAo offers a quick and reliable noninvasive means of assessing hemodynamically significant CoA.

Tetralogy of Fallot: impact of the excursion of the interventricular septum on left ventricular systolic function and fibrosis after surgical repair.

PURPOSE: To quantify the excursion of interventricular septum (IVS) in patients after repair of tetralogy of Fallot (TOF), a marker of interventricular interaction, and assess its association with left ventricular (LV) ejection fraction, LV septal wall thickening, and LV fibrosis. MATERIALS AND METHODS: The HIPAA-compliant protocol received institutional board review approval. IVS excursion was measured at cardiovascular magnetic resonance (MR) imaging in 82 patients after repair of TOF and in 10 healthy volunteers. IVS excursion was correlated with LV ejection fraction, LV septal wall thickening, and LV delayed gadolinium enhancement. Independent predictors of reduced LV ejection fraction were identified, including significant univariable predictors with use of a multivariable logistic regression model. RESULTS: IVS excursion was greater in patients than in healthy volunteers (5.3 mm ± 3.1 vs 1.2 mm ± 0.4, P < .01). Patients (n = 68) with abnormal excursion of the IVS had reduced LV ejection fraction (57% ± 7 vs 61% ± 4, P < .01) and reduced LV septal wall thickening (24% ± 10 vs 29% ± 5, P = .01) compared with patients with normal IVS excursion. Maximal IVS excursion (odds ratio = 1.27 per millimeter, P = .03) and right ventricular (RV) ejection fraction (odds ratio = 0.92 per percentage, P = .031) were independent predictors of reduced LV ejection fraction (<55%). Among the 44 patients with delayed enhancement images, those with abnormal excursion of the IVS had higher LV delayed enhancement scores (median, 1.5 [interquartile range, 0-2] vs 0 [interquartile range, 0-0]; P < .01] than patients with normal IVS excursion. Notably, in all but one patient the delayed enhancement was located at the RV-LV hinge points. CONCLUSION: Abnormal IVS excursion after repair of TOF is associated with reduced global and septal LV systolic function and LV fibrosis at the RV-LV hinge points, suggesting a mechanism of adverse interventricular interaction.

Cardiovascular MRI for the assessment of heart failure: focus on clinical management and prognosis.

Cardiovascular MR (CMR) has an emerging role in the noninvasive diagnostic assessment of heart failure (HF). Different imaging sequences allow for a detailed assessment of cardiac morphology, function, myocardial perfusion, tissue characterization, and blood flow measurement. This article reviews the key applications of CMR in HF, with special focus on how CMR may influence the diagnostic and therapeutic approach of HF patients.

Unroofing the diagnosis.

Unroofed coronary sinus is a rare congenital cardiac anomaly in which a communication occurs between the coronary sinus and the left atrium due to the partial or complete absence of roof of the coronary sinus. Its diagnosis is important to prevent pulmonary hypertension and brain abscess or cerebral emboli. We report a case of a symptomatic 35-year-old man in which no atrial septal defects were visualized by transesophageal echocardiography but MRI permitted the diagnosis of this rare cardiac anomaly and assessment of shunt severity.

Hypertrophic cardiomyopathy with restrictive phenotype and myocardial crypts.

This report describes a 22-year-old woman who has clinical and physiologic features of a restrictive cardiomyopathy. Magnetic resonance imaging showed myocardial delayed enhancement and interventricular septal crypts characteristic of hypertrophic cardiomyopathy (HCM). Transcatheter biopsy confirmed the diagnosis, revealing marked myocyte hypertrophy, interstitial fibrosis, and fiber disarray, which are findings consistent with HCM. A review of the literature suggests that this is the first case of HCM reported with a restrictive pattern and myocardial crypts.