Keyur Parekh

Extranodal Rosai-Dorfman Disease Involving the Left Atrium: Cardiac MRI, CT, and PET Scan Findings

Rosai-Dorfman disease (RDD) is a rare entity that usually involves the lymph nodes but extranodal involvements have been seen in numerous cases, although RDD with cardiovascular involvement is extremely rare. We describe a case of a young male who presented with intermittent palpitations and was found to have a left atrium mass. Our case not only emphasizes the rarity of the above lesion but also highlights the importance of modern-day imaging like computed tomography, Cardiac Magnetic Resonance Imaging (CMRI), and PET scan in characterizing such nonspecific lesions and directing appropriate line of treatment. RDD should be considered as one of the differentials even for isolated cardiac lesions.

Cross-sectional imaging of perforated gallbladder

Gallbladder perforation is a potentially life-threatening condition commonly seen as a complication of acute cholecystitis. Urgent surgical intervention is often needed to reduce serious morbidity and mortality. It presents a diagnostic challenge due to nonspecific symptoms, leading to a delay in diagnosis. Imaging plays a vital role in early identification of this potentially fatal condition and evaluation by more than one imaging modality may be required to make the diagnosis. Knowledge of specific and ancillary imaging findings is crucial to avoid misdiagnosis. In this article, we will review the risk factors, pathophysiology, and surgical classification of gallbladder perforation and discuss the role of multimodality imaging in its diagnosis. Differential diagnoses on imaging will also be discussed.

Assessment of myocardial motion in children and young adults using High-temporal resolution MR tissue phase mapping

Background MR Tissue phase mapping (TPM) is a non-invasive tool to detect regional and global myocardial wall motion. Evaluation of myocardial velocity in radial and longitudinal direction throughout the cardiac cycle may help us better understand myocardial mechanics. Our goal is to investigate regional and global left ventricular myocardial motion using respiratory-gated high temporal resolution TPM in children and young adults. Methods

Co-registered MR tissue phase mapping and speckle tracking echocardiography: inter-modality comparison of regional myocardial velocities in pediatric patients

Background MR tissue phase mapping (TPM) enables assessment of regional myocardial velocities. The purpose of this study was to compare regional myocardial velocities obtained by both TPM and speckle tracking echocardiography (STE) to assess agreement and potential systematic differences between modalities. Methods

Raghib Syndrome Presenting as a Cryptogenic Stroke: Role of Cardiac MRI in Accurate Diagnosis

Raghib Syndrome is a rare developmental complex, which consists of persistence of the left superior vena cava (PLSVC) along with coronary sinus ostial atresia and atrial septal defect. This Raghib complex anomaly has also been associated with other congenital malformations including ventricular septal defects, enlargement of the tricuspid annulus, and pulmonary stenosis. Our case demonstrates an isolated PLSVC draining into the left atrium along with coronary sinus atresia in a young patient presenting with cryptogenic stroke without the atrial septal defect. Majority of the cases reported in the literature were found to have the lesion during the postmortem evaluation or were characterized at angiography and/or echocardiography. We stress the importance of modern day imaging like the computed tomography (CT) angiography and cardiac MRI in diagnosis and surgical management of such rare lesions leading to cryptogenic strokes.

Quantitative non-contrast T1 mapping of left ventricle in children and young adults

Methods The HIPAA compliant prospective study was IRB approved. Sixteen patients (mean age 15.4 years; range 5-25 years) underwent cardiac magnetic resonance (CMR) (1.5-T) including non-contrast short axis T1 mapping (modified Look-Locker [MOLLI] sequence). Twelve patients with no intrinsic myocardial abnormality based on clinical history, standard biomarkers and echocardiographic criteria were compared with 3 patients having cardiac dysfunction and 1 patient with hypertrophic cardiomyopathy (HCM). Short axis images were manually contoured to outline the epicardium and endocardium using AHA 16-segment model yielding 192 normal myocardial segments, 48 segments in patients with cardiac dysfunction, and 16 segments in a patient with HCM. Patient groups were compared using one-way analysis of co-variance (ANOVA). Chi-squared test was performed to compare appropriateness of discrete data. Receiver operating characteristic (ROC) curve was used to obtain a cut-off value of T1 relaxation time. Statistical significance was defined as p < 0.05.

Incorporating time-resolved three-dimensional phase contrast (4D flow) MRI in clinical workflow: initial experiences at a large tertiary care medical center

Background Time-resolved three-dimensional phase contrast (4D flow) MRI allows for visualization of three-dimensional cardiovascular anatomy and pulsatile flow with full volumetric coverage in a single, easy to prescribe 3D acquisition. The technique provides comprehensive flow visualization and permits retrospective flow quantification at any user-defined region of interest. [1] To our knowledge, no center has incorporated 4D flow MRI as a part of standard clinical cardiovascular MRI (CMR). The goals of this study include: 1) reporting on the incorporation of 4D flow MRI acquisition and processing as part of clinical CMR workflow and 2) better understanding the clinical impact of 3D flow visualization and retrospective flow quantification derived from 4D flow MRI in CMR.

Native T1 mapping in children and young adults with hypertrophic cardiomyopathy

To assess the global and segmental left ventricular (LV) native T1 and extracellular volume fraction (ECV) in children and young adults with hypertrophic cardiomyopathy (HCM) compared to a control cohort. The study population included 21 HCM patients (mean 14.1 ± 4.6 years) and 21 controls (mean 15.7 ± 1.5 years). Native modified Look-Locker inversion recovery sequence was performed before and after contrast injection in 3 short axis planes. Global and segmental LV native T1 and ECV were quantified and compared between HCM patients and controls. Mean native T1 in HCM patients and controls was 1020.4 ± 41.2 and 965.6 ± 30.2 ms respectively (p < 0.0001). Hypertrophied myocardium had significantly higher native global T1 and global ECV compared to non-hypertrophied myocardium in HCM (p < 0.0001, = 0.14 and 0.048, = 0.01 respectively). In a subset of patients, ECV was higher in LV segments with LGE compared to no LGE (p < 0.0001). No significant correlation was identified between global native T1 and ECV and parameters of LV structure and function. Native T1 cut-off of 987 ms provided the highest sensitivity (95 %) and specificity (91 %) to separate HCM patients from controls. Global and segmental native T1 are elevated in HCM patients. LV segments with hypertrophy and/or LGE had higher ECV in a subset of HCM patients. LV native T1 and ECV do not correlate with parameters of LV structure and function. T1 in children and young adults may be used as a non-invasive tool to assess for HCM and related fibrosis.

Characterization of dilated cardiomyopathy using tissue phase mapping and extracellular volume measurement

Background Non-ischemic dilated cardiomyopathy (DCM) is a relatively common cause of left ventricular dysfunction. Microscopic scar may be a cause of regional and global left ventricular dysfunction in DCM patients. The aim of this study was to evaluate changes in regional myocardial structure, function, and dyssynchrony using a novel noninvasive MR imaging protocol. Methods Eleven patients with suspected non-ischemic cardiomyopathy underwent cardiac MRI (CMR) on a 1.5T magnet (Magnetom Avanto or Aera, Siemens Healthcare, Erlangen, Germany). In addition to the conventional CMR viability protocol, patients underwent both tissue phase mapping (TPM) and T1 mapping with a modified look-locker inversion recovery (MOLLI) technique pre and between 10 and 25 minutes post 0.2 mmol/kg adminstration of an extracellular gadolinium agent. These sequences were performed through the left ventricle in the short axis orientation at basal, mid-chamber, and apical levels. The hematocrit was collected within 48 hours of the CMR to calculate segmental ECV values as described by Kellman, et al., as a marker of microscopic fibrosis. TPM analysis was used to determine the degree of segmental wall motion abnormality. Radial, longitudinal and absolute velocities

Quantitative cardiac MR assessment of left ventricular diastology

Background Cardiac MR (CMR) is the accepted gold standard for the assessment of myocardial scar and biventricular systolic function. Bright blood cine imaging with phase-contrast mitral inflow assessment has shown promise for the evaluation of left ventricular (LV) diastology. The purpose of this study is to evaluate the accuracy of LV diastolic function grading by CMR, using Doppler echocardiography as the reference standard. We hypothesize that quantitative CMR analysis of diastolic function coupled with left atrial volume (LAV) assessment is accurate in characterizing LV diastology. Methods 83 patients without mitral valve disease (47 men, average age 53 years) underwent CMR imaging on a 1.5T scanner for evaluation of myocardial viability or infiltrative heart disease. All patients underwent 2-D phase-contrast (PC) imaging of the mitral valve (TR/TE 48/2.2, FA 30 degrees, VENC 80 cm/s, 20 phases, bw 554). Brightblood (BB) 4- and 2-chamber cine imaging was performed (TR/TE 13/1.1, FA 69 degrees, 40 to 50 phases, BW 933) for lateral mitral annular and left atrial volume (LAV) assessment. Peak E and A velocities were obtained from PC data. 4-chamber BB cine images were analyzed using prototype software evaluating deformation fields to automatically identify and track the mitral base plane at the lateral and septal insertions, extracting lateral e’ values (Siemens Corp., Corporate Technology, Princeton, New Jersey). LAV was obtained using the lengtharea method. LV diastolic function was graded using established echocardiographic criteria. Differences in means were assessed using the student’ st -test. Results