Clinical experiences of delayed contrast enhancement with cardiac computed tomography: case series

Sidhu et al. BMC Research Notes 2013, 6:2 http://www.biomedcentral.com/1756-0500/6/2 SHORT REPORT Open Access Clinical experiences of delayed contrast enhancement with cardiac computed tomography: case series Manavjot S Sidhu*†, Brian B Ghoshhajra†, Shanmugam Uthamalingam, Niamh Kilcullen, Leif-Christopher Engel, Hector M Medina, Vikram Venkatesh, Yongkasem Vorasettakarnkij, Udo Hoffmann, Ricardo C Cury, Suhny Abbara and Thomas J Brady Abstract Background: Myocardial delayed enhancement (MDE) by gadolinium-enhanced cardiac MRI is well established for myocardial scar assessment in ischemic and non-ischemic heart disease. The role of MDE by cardiac CT (CT-MDE) is not yet defined. Findings: We reviewed all clinical cases of CT-MDE at a tertiary referral center to present the cases as a case series. All clinical cardiac CT exams which utilized CT-MDE imaging between January 1, 2005 and October 1, 2010 were collected as a series and their findings were also compared with available myocardial imaging to assess for myocardial abnormalities, including echocardiography (wall motion, morphology), cardiac MRI (delayed enhancement, morphology), SPECT MPI (perfusion defects). 5,860 clinical cardiac CT exams were performed during the study period. CT-MDE was obtained in 18 patients and was reported to be present in 9 patients. The indications for CT-MDE included ischemic and non-ischemic heart diseases. In segments positive for CT-MDE, there was excellent agreement of CT with other modalities: echocardiography (n=8) demonstrated abnormal morphology and wall motion (k=1.0 and k=0.82 respectively); prior MRI (n=2) demonstrated abnormal delayed enhancement (MR-MDE) (k=1.0); SPECT MPI (n=1) demonstrated fixed perfusion defects (k=1.0). In the subset of patients without CT-MDE, no abnormal segments were identified by echocardiography (n=8), MRI (n=1) and nuclear MPI (n=0). Conclusions: CT-MDE was performed in rare clinical situations. The indications included both ischemic and non-ischemic heart disease and there was an excellent agreement between CT-MDE and abnormal myocardium by echocardiography, cardiac MRI, and nuclear MPI. Findings We reviewed all clinical cases of CT-MDE at a tertiary referral center to present the cases as a case series. All clinical cardiac CT exams which utilized CT-MDE imaging between January 1, 2005 and October 1, 2010 were collected as a series and their findings were also compared with available myocardial imaging to assess for myocardial abnormalities, including echocardiography (wall motion, morphology), cardiac MRI (delayed * Correspondence: † Equal contributors Department of Cardiovascular Imaging, Cardiac MR PET CT Program, Department of Radiology and Division of Cardiology, Massachusetts General Hospital and Harvard Medical School, 165 Cambridge Street, Suite 400, Boston, MA 02114, USA enhancement, morphology), SPECT MPI (perfusion defects) 5,860 clinical cardiac CT exams were performed during the study period. CT-MDE was obtained in 18 patients and was reported to be present in 9 patients. The indications for CT-MDE included ischemic and non-ischemic heart diseases. In segments positive for CT-MDE, there was excellent agreement of CT with other modalities: echocardiography (n=8) demonstrated abnormal morphology and wall motion (k=1.0 and k=0.82 respectively); prior MRI (n=2) demonstrated abnormal delayed enhancement (MR-MDE) (k=1.0); SPECT MPI (n=1) demonstrated fixed perfusion defects (k=1.0). In the subset of patients without CT-MDE, no abnormal segments were identified by echocardiography (n=8), MRI (n=1) and nuclear MPI (n=0). © 2013 Sidhu et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Sidhu et al. BMC Research Notes 2013, 6:2 http://www.biomedcentral.com/1756-0500/6/2 Introduction Cardiac magnetic resonance imaging (MRI) with gadolinium can detect myocardial delayed enhancement (MDE) [1] and has become the clinical imaging standard for the evaluation of myocardial infarction and scar. MDE is also useful in identifying myocardial injury and in the assessment of infiltrative, inflammatory diseases of the heart , ischemic heart disease and even in cardiac neoplasm [2]. However, there are numerous contraindications to cardiac MRI, including severe claustrophobia, several arrhythmias, metal implants and severe renal insufficiency (a risk factor for nephrogenic systemic fibrosis). In these patients, the clinical need for an alternative diagnostic tool for scar/injury imaging occasionally arises. Cardiac computed tomography (CT) can identify MDE with iodinated contrast material because the pharmacokinetics of iodinated agents are very similar to those of gadolinium-DTPA [3,4]. Both agents are retained in tissue with an increased volume of distribution including myocardial infarction and scar. A number of studies are underway to assess the role of cardiac CT using MDE. In this report, we review our clinical experience where CT-MDE was performed to yield insights into application of this novel technique. We retrospectively reviewed all clinical cases of CTMDE at a tertiary care referral center to present our experience as a series of cases. Methods Study design A waiver was obtained from our Institutional Review Board (Partners Healthcare IRB) for this retrospective study. All clinical cardiac CT exams performed from January 1, 2005 to October 1, 2010 were included, regardless of indication. Cases performed for research purposes were excluded. The text of all reports was screened for the use of a delayed enhancement protocol. Reports were then manually reviewed to refine the list to those patients who underwent delayed imaging purely for the purpose of MDE assessment. For example, early or immediate delayed phase images obtained for thrombus detection in the cardiac chambers were excluded (i.e. 2-minute delayed scans for atrial appendage thrombus exclusion). The cardiac CT images, reports and electronic records were also reviewed for technique, technical parameters (tube voltage, tube current, gating, timing, slice thickness), radiation dose (dose length product as obtained from the dose exposure record), and image quality (subjective assessment as dictated by interpreting reader). Images were analyzed to determine the contrast-to-noise ratio using regions of interest in the abnormal myocardium and the remote normal myocardium. Page 2 of 7 Using the AHA 17 segment model [5], myocardial segments on CT images were then identified. To corroborate CT-MDE findings in patients, all cardiac imaging modalities performed within a period of three months were retrieved and reviewed. These included 2-dimensional echocardiography, cardiac MRI, and single photon emission cardiac tomogram (SPECT (...truncated)