Publications by authors named "Krishnam M"

Aneurysms of the interventricular membranous septum are a rare anatomical feature that can be detected incidentally on computed tomography or echocardiography. Such aneurysms can pose challenges in the treatment of patients with aortic valve stenosis. A case series of 2 patients with membranous septal aneurysms treated successfully with current-generation balloon-expandable and self-expanding transcatheter heart valves is presented here.

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Background: Cardiac magnetic resonance is a useful clinical tool to identify late gadolinium enhancement in heart failure patients with implantable electronic devices. Identification of LGE in patients with CIED is limited by artifact, which can be improved with a wide band radiofrequency pulse sequence.

Objective: The authors hypothesize that image quality of LGE images produced using wide-band pulse sequence in patients with devices is comparable to image quality produced using standard LGE sequences in patients without devices.

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Microvascular injury immediately following reperfusion therapy in acute myocardial infarction (MI) has emerged as a driving force behind major adverse cardiovascular events in the postinfarction period. Although postmortem investigations and animal models have aided in developing early understanding of microvascular injury following reperfusion, imaging, particularly serial noninvasive imaging, has played a central role in cultivating critical knowledge of progressive damage to the myocardium from the onset of microvascular injury to months and years after in acute MI patients. This review summarizes the pathophysiological features of microvascular injury and downstream consequences, and the contributions noninvasive imaging has imparted in the development of this understanding.

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Purpose: Widely used conventional 2D T * approaches that are based on breath-held, electrocardiogram (ECG)-gated, multi-gradient-echo sequences are prone to motion artifacts in the presence of incomplete breath holding or arrhythmias, which is common in cardiac patients. To address these limitations, a 3D, non-ECG-gated, free-breathing T * technique that enables rapid whole-heart coverage was developed and validated.

Methods: A continuous random Gaussian 3D k-space sampling was implemented using a low-rank tensor framework for motion-resolved 3D T * imaging.

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There is emerging evidence that the cardiac interatrial septum has an important role as a thromboembolic source for ischemic strokes. There is little consensus on treatment of patients with different cardiac interatrial morphologies or pathologies who have had stroke. In this paper, we summarize the important background, diagnostic, and treatment considerations for this patient population as presented during the Federation of American Societies for Experimental Biology (FASEB) Virtual Catalytic Conference on the Cardiac Interatrial Septum and Stroke Risk, held on December 7, 2022.

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Purpose: The objective is to show that TR-MRA is a useful non-invasive technique without ionizing radiation of traditional angiography in evaluating VMs.

Materials And Methods: Retrospective search utilizing M-Power for MRA studies done at 3 T (Trio, Siemens) with both 3D contrast enhanced TR-MRA and 3D CE-MRA sequences from 2009 to 2018 were obtained after IRB approval. The images were blindly reviewed by two experienced cardiovascular radiologists for informations regarding vascular malformations with the ability to separate arteries and veins without any overlay or contamination in real time.

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Sudden blockage of arteries supplying the heart muscle contributes to millions of heart attacks (myocardial infarction, MI) around the world. Although re-opening these arteries (reperfusion) saves MI patients from immediate death, approximately 50% of these patients go on to develop chronic heart failure (CHF) and die within a 5-year period; however, why some patients accelerate towards CHF while others do not remains unclear. Here we show, using large animal models of reperfused MI, that intramyocardial hemorrhage - the most damaging form of reperfusion injury (evident in nearly 40% of reperfused ST-elevation MI patients) - drives delayed infarct healing and is centrally responsible for continuous fatty degeneration of the infarcted myocardium contributing to adverse remodeling of the heart.

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Article Synopsis
  • - This text discusses a patient with pericardial amyloidosis linked to lymphoplasmacytic lymphoma, experiencing ongoing shortness of breath and coughing.
  • - It emphasizes the diverse ways cardiac amyloidosis can present in patients, showcasing that symptoms can differ widely.
  • - Additionally, it points out the uncommon but significant instances of light-chain and heavy-chain amyloidosis affecting the pericardium, which is the fibrous sac surrounding the heart.
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Intracardiac metastasis of the testicular cancer is very rare phenomenon. A 30-year-old-man with a history of testicular rhabdomyosarcoma and lung metastases was found to have an intracardiac filling defect in a surveillance computed tomography scan 3 years after the initial diagnosis. A cardiac magnetic resonance imaging study was performed for further evaluation and demonstrated a lobulated, heterogeneously enhancing mobile mass within the right ventricle attaching to the anterior papillary muscle.

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Unilateral absence of pulmonary artery is a rare developmental anomaly. Infrahepatic inferior vena cava interruption is a well-recognized but uncommon developmental anomaly. Presence of both these anomalies in a single individual is extremely rare.

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Objectives: To evaluate coronary artery calcification (CAC) on routine CT chest in hospitalised HIV patients and to assess individual risk factors.

Methods: Routine CT chests, May 2010-November 2015, of 143 hospitalised HIV-positive patients were reviewed for qualitative assessment of calcification in major coronary arteries by two radiologists. Presence, location and burden of calcification were evaluated on 3 mm axial images of CT chest.

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Magnetic resonance imaging (MRI) plays an increasingly important role in the non-invasive evaluation of the pulmonary vasculature. MR angiographic (MRA) techniques provide morphological information, while MR perfusion techniques provide functional information of the pulmonary vasculature. Contrast-enhanced MRA can be performed at high spatial resolution using 3D T1-weighted spoiled gradient echo sequence or at high temporal resolution using time-resolved techniques.

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Aim: This study aimed to define the relationship between pulse pressure (PP) and coronary artery calcification (CAC), a proven surrogate marker for coronary heart disease.

Patients And Methods: A total of 170 participants 50-70 years of age from 11 villages of Yunnan Province of China were enrolled randomly into this study. They were examined routinely for diastolic and systolic blood pressure, PP, and CAC.

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Aim: Postmyocardial infarction ventricular septal defect (VSD) is a rare complication that can lead to rapid hemodynamic patient decompensation. The type of VSD repair relies on several factors including: size, location, timing and surgical expertise.

Case: A 63-year-old man with a ST-elevation myocardial infarction underwent percutaneous coronary intervention of the right coronary artery.

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Background: Coronary artery calcium (CAC) is an established predictor of future major adverse atherosclerotic cardiovascular events in asymptomatic individuals. However, limited data exist as to how CAC compares with functional testing (FT) in estimating prognosis in symptomatic patients.

Methods: In the PROMISE trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain), patients with stable chest pain (or dyspnea) and intermediate pretest probability for obstructive coronary artery disease were randomized to FT (exercise electrocardiography, nuclear stress, or stress echocardiography) or anatomic testing.

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Importance: Radiation doses for computed tomography (CT) vary substantially across institutions.

Objective: To assess the impact of institutional-level audit and collaborative efforts to share best practices on CT radiation doses across 5 University of California (UC) medical centers.

Design, Setting, And Participants: In this before/after interventional study, we prospectively collected radiation dose metrics on all diagnostic CT examinations performed between October 1, 2013, and December 31, 2014, at 5 medical centers.

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Purpose To determine patient, vendor, and institutional factors that influence computed tomography (CT) radiation dose. Materials and Methods The relevant institutional review boards approved this HIPAA-compliant study, with waiver of informed consent. Volume CT dose index (CTDI) and effective dose in 274 124 head, chest, and abdominal CT examinations performed in adult patients at 12 facilities in 2013 were collected prospectively.

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Purpose: To summarize data on computed tomographic (CT) radiation doses collected from consecutive CT examinations performed at 12 facilities that can contribute to the creation of reference levels.

Materials And Methods: The study was approved by the institutional review boards of the collaborating institutions and was compliant with HIPAA. Radiation dose metrics were prospectively and electronically collected from 199 656 consecutive CT examinations in 83 181 adults and 3871 consecutive CT examinations in 2609 children at the five University of California medical centers during 2013.

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Objectives: Quantitative assessment of left ventricular (LV) functional parameters in cardiac MR requires time-consuming contour tracing across multiple short axis images. This study assesses global LV functional parameters using 3-slice segmentation on steady state free precision (SSFP) cine short axis images and compares the results with conventional multi-slice segmentation of LV.

Methods: Data were collected from 61 patients who underwent cardiac MRI for various clinical indications.

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Objective: Dynamic changes in anatomic geometry of the inferior vena cava from changes in intravascular volume may cause passive stresses on inferior vena cava filters. In this study, we aim to quantify variability in inferior vena cava dimensions and anatomic orientation to determine how intravascular volume changes may impact complications of inferior vena cava filter placement, such as migration, tilting, perforation, and thrombosis.

Methods: Retrospective computed tomography measurements of major axis, minor axis, and horizontal diameters of the inferior vena cava at 1 and 5 cm below the lowest renal vein in 58 adult trauma patients in pre-resuscitative (hypovolemic) and post-resuscitative (euvolemic) states were assessed in a blinded fashion by two independent readers.

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Introduction: Median arcuate ligament syndrome (MALS) is a rare disorder defined by compression and narrowing of the celiac artery by the median arcuate ligament. The increased blood flow through the pancreaticoduodenal arcade can lead to the aneurysmal formation within the vessel. We report 3 cases of pancreaticoduodenal arterial aneurysms (PDAAs) in patients with MALS whose aneurysms were occluded, but celiac artery revascularization was not performed.

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Objective: To assess the role of CT angiography in the evaluation of patients with lower extremity gunshot wounds in the emergency room.

Materials And Methods: Eighty patients (73 male, 7 female, mean age 26 years) underwent CT angiography for the evaluation of lower extremity gunshot injuries. Imaging was conducted on the basis of standardized protocols utilizing 16-slice and 64-slice multidetector systems and images were qualitatively graded and assessed for various forms of arterial injury.

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The increase in radiation exposure due to CT scans has been of growing concern in recent years. CT scanners differ in their capabilities, and various indications require unique protocols, but there remains room for standardization and optimization. In this paper, the authors summarize approaches to reduce dose, as discussed in lectures constituting the first session of the 2013 UCSF Virtual Symposium on Radiation Safety and Computed Tomography.

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