Cardiac Multidetector CT Research Articles

A rare cause of abnormal pulmonary venous drainage: septum primum malposition.

This study aimed to evaluate the clinical features of patients with septum primum malposition, imaging tools used for diagnosis, and their effects on the surgical approach. Patients diagnosed with septum primum malposition in our paediatric cardiac centre between 1 January, 2015 and 1 January, 2019 were included in the study. In all patients, the age, reason for admission, transthoracic echocardiography, cardiac multidetector CT angiography findings, and subsequent surgical data were evaluated. Fifteen patients were diagnosed with septum primum malposition during the study period. The median age was 12 months (2 months-10 years). Six patients were left isomeric, and the rest were situs solitus; 80% of the patients (n = 12) had additional secundum atrial septal defect. There was cardiac pathology in 46% of the patients (n = 7) in addition to the abnormal pulmonary venous drainage, ventricular septal defect (n = 3), left ventricularhypoplasia (n = 2), cortriatriatum sinister (n = 2), double outlet right ventricle (n = 1), and atrioventricular septal defect (n = 1). There was bilateral superior caval vein in three patients, right-sided superior caval vein in 11 patients, and left-sided superior caval vein in one patient. All three patients with total abnormal pulmonary venous drainage were left atrial isomeric. There were differences between the results of transthoracic echocardiography and CT angiographies in two patients. The surgical strategy was changed in three patients after the preoperative diagnosis of septum primum malposition. Septum primum malposition should be kept in mind during the imaging of complex CHDs specifically during the segmental analysis of the pathologies with heterotaxy syndromes; it should be differentiated from other aetiologies of abnormal pulmonary venous drainage as accurate diagnosis would facilitate the ideal surgery in these complex pathologies requiring a detailed preoperative preparation.

Intermodality agreement between TTE and low kVp ECG-gated MDCTA in diagnosis of complex CHD in pediatrics

BackgroundTransthoracic echocardiography (TTE) is considered the primary diagnostic modality in congenital heart disease (CHD). However, it has limited role in evaluation of extra-cardiac major vessels abnormalities. Cardiac catheterization angiography is considered the gold standard investigation, yet, it is invasive. The aim of this study is to evaluate the agreement between TTE and low kVp ECG-gated cardiac multi-detector CT angiography (MDCTA) in detecting cardiac and extra-cardiac findings of complex congenital heart disease in a sample size of 36 patients (19 males and 17 females) with an age ranged between 30 days and 12 years (mean age 25.5 months). All cases were diagnosed to have complex CHD clinically and by TTE then referred to undergo cardiac low kVp ECG-gated MDCTA to confirm diagnosis and for better assessment of extra-cardiac major vessels abnormalities. Data derived from both modalities were then compared to calculate the inter-technique variability by using Cohen’s kappa statistics.ResultsTTE diagnosed 96% of intra-cardiac anomalies and only 54% of extra-cardiac major vessels anomalies detected by MDCTA, with variable degrees of intermodality agreement in detection different anomalies ranging between perfect agreement in diagnosing most of intra-cardiac lesions and very poor agreement in diagnosing extra-cardiac SVC anomalies.ConclusionLow kVp ECG-gated cardiac MDCTA is a rapid, non-invasive and reliable diagnostic modality in complex congenital heart diseases. It confirms TTE findings in intra-cardiac anomalies and significantly surpasses TTE reliability in diagnosis of extra-cardiac major vessels anomalies. So, it is indispensable as part of adequate preoperative assessment algorithm in cases of complex CHD and can't be replaced by TTE even with the later providing accurate assessment of intra-cardiac anomalies.

Assessing right ventricular function in patients with pulmonary artery hypertension based on noninvasive measurements: correlation between cardiac MRI, ultrasonic cardiogram, multidetector CT and right heart catheterization

Objective: To compare the value of cardiac MRI (CMRI), ultrasonic cardiogram (UCG), multidetector CT (MDCT) in assessing right ventricular function (RV) in patients with PAH. Methods: A total of 31 consecutive patients with PAH (17 males and 14 females, 55±12 years) in Beijing Chao-Yang Hospital from August 2012 to February 2014 were prospectively enrolled. All patients underwent CMRI to get parameters including right ventricular end-systolic volume (ESV), end-diastolic dimension (EDV), stroke volume (SV), ejection fraction (EF), ventricular mass index (VMI). UCG parameters included Tei index, RV fractional area change (FAC), ESV, EDV. MDCT parameters included right /left ventricular internal diameter (RVd/LVd), right /left ventricular diastole maximum area (RVa/LVa), Cobb angle.These parameters obtained by MRI, UCG and MDCT were correlated with those of RHC respectively by Spearman or Pearson correlation analysis. Results: Six minutes walk distance had moderate negative correlation with CMRI-EF (40±9), VMI 44-115(71±20) g/m(2,) Cobb angle(67°±12°); RHC-SV had moderate negative correlation with CMRI-SV(57±21) ml, EF, VMI, UCG-EF(41±14), Tei(0.82±0.29), FAC(30±9), RVd(45±7) mm, RVa(2 484±596) mm(2), Cobb angle ; Right cardiac work index had moderate negative correlation with CMRI-EF, RVd and Cobb angle. Conclusions: MRI-EF is the best parameter to reflect RV function. CMRI is the optimal method to assess RV function, and then is the MDCT and the last is UCG.

Significant reduction of left atrial volume concomitant with clinical improvement after percutaneous transluminal septal myocardial ablation for drug-refractory hypertrophic obstructive cardiomyopathy, and its precise detection with multidetector CT

ObjectiveIn patients with hypertrophic obstructive cardiomyopathy (HOCM), left atrial (LA) volume measurement is very important to provide prognostic information. Recent studies demonstrated that multidetector CT (MDCT) is useful to assess...

Assessing right ventricular function in patients with pulmonary hypertension based on noninvasive measurements: correlation between cardiac MRI, ultrasonic cardiogram, multidetector CT and right heart catheterization

Assessing right ventricular function in patients with pulmonary hypertension based on noninvasive measurements: correlation between cardiac MRI, ultrasonic cardiogram, multidetector CT and right heart catheterization

Hemitruncus with large patent ductus arteriosus simulating d-transposition of great arteries

This report describes a rare case with hemitruncus with large left sided patent ductus arteriosus with severe pulmonary hypertension with reversal of shunt across patent ductus simulating transposition of great arteries. The case illustrates the role of echocardiography and cardiac multidetector CT in diagnosing such complex congenital heart disease.

An incidentally detected huge coronary arteriovenous fistula: Comprehensive evaluation using noninvasive imaging modalities

A 58-year-old woman presenting with atypical chest pain showed a turbulent color Doppler signal at the interatrial septum on a transthoracic echocardiography and was found to have a huge coronary arteriovenous fistula originating from the middle right coronary artery and draining into right atrium with a very tortuous course using cardiac multidetector CT. A trivial echocardiographic finding should not be overlooked and could be evaluated thoroughly and noninvasively by multidetector CT.

Current Role of Cardiac and Extra-Cardiac Pathologies in Clinically Indicated Cardiac Computed Tomography with Emphasis on Status Before Pulmonary Vein Isolation

The aim of this study was to assess the incidence of cardiac and significant extra-cardiac findings in clinical computed tomography of the heart in patients with atrial fibrillation before pulmonary vein isolation (PVI). 224 patients (64 ± 10 years; male 63 %) with atrial fibrillation were examined by cardiac 64-slice multidetector CT before PVI. Extra-cardiac findings were classified as "significant" if they were recommended to additional diagnostics or therapy, and otherwise as "non-significant". Additionally, cardiac findings were documented in detail. A total of 724 cardiac findings were identified in 203 patients (91 % of patients). Additionally, a total of 619 extra-cardiac findings were identified in 179 patients (80 % of patients). Among these extra-cardiac findings 196 (32 %) were "significant", and 423 (68 %) were "non-significant". In 2 patients (1 %) a previously unknown malignancy was detected (esophageal cancer and lung cancer, local stage, no metastasis). 203 additional imaging diagnostics followed to clarify the "significant" findings (124 additional CT, costs 38 314.69 US dollars). Overall, there were 3.2 cardiac and 2.8 extra-cardiac findings per patient. Extra-cardiac findings appear significantly more frequently in patients over 60 years old, in smokers and in patients with a history of cardiac findings (p <0.05). Cardiac CT scans before PVI should be screened for extracardiac incidental findings that could have important clinical implications for each patient.

Cardiac multidetector CT: method, indications and applications

•. Cardiac CT is a rapidly developing field offering a viable non-invasive alternative to conventional coronary angiography. •. The development of CT technology often outpaces evaluation of its benefit; however 64 slice multidetector CT is now considered as a reference standard for cardiac CT examination. •. Careful selection of patients and optimisation of CT technique is essential to obtain high-quality images and minimise the radiation dose to the patients. •. Although cardiac CT is primarily used for the assessment of coronary artery disease in low- and intermediate-risk patients, it can be used in a range of other indications, including assessment of coronary artery bypass grafts (CABGs), cardiac valves, congenital cardiac anomalies, the left atrium prior to electrophysiology treatment and assessment of suitability for trans-catheter aortic valve implantation. •. The scope of cardiac CT continues to expand and future developments where cardiac CT is likely to be useful include coronary plaque assessment and perfusion imaging. The potential to non-invasively image the heart has led to the rapid development and dissemination of cardiac CT. With the advent of 64 slice systems, cardiac multidetector CT continues to evolve as an essential tool in the investigation of many cardiac conditions. It is now routinely used to provide accurate information about coronary artery disease, cardiac anatomy and congenital anomalies, coronary artery bypass grafts, cardiac valves and pulmonary vein/left atrial anatomy. However, its value in the assessment of coronary stents, ventricular function and coronary plaque morphology remains limited and requires further research. Although cardiac CT is a robust technique, it requires careful patient selection and close interaction between radiologists and cardiologists. It is also considered a radiation-intensive examination and requires careful planning to consistently achieve low levels of radiation exposure to patients. In this review we describe the optimal technique of performing cardiac CT. We also summarise the current indications of cardiac CT and discuss the evidence for various applications.

ACR Appropriateness Criteria® Acute Nonspecific Chest Pain—Low Probability of Coronary Artery Disease

This document outlines the usefulness of available diagnostic imaging for patients without known coronary artery disease and at low probability for having coronary artery disease who do not present with classic signs, symptoms, or electrocardiographic abnormalities indicating acute coronary syndrome but rather with nonspecific chest pain leading to a differential diagnosis, including pulmonary, gastrointestinal, or musculoskeletal pathologies. A number of imaging modalities are available to evaluate the broad spectrum of possible pathologies in these patients, such as chest radiography, multidetector CT, MRI, ventilation-perfusion scans, cardiac perfusion scintigraphy, transesophageal and transthoracic echocardiography, PET, spine and rib radiography, barium esophageal and upper gastrointestinal studies, and abdominal ultrasound. It is considered appropriate to start the assessment of these patients with a low-cost, low-risk diagnostic test such as a chest x-ray. Contrast-enhanced gated cardiac and ungated thoracic multidetector CT as well as transthoracic echocardiography are also usually considered as appropriate in the evaluation of these patients as a second step if necessary. A number of rest and stress single-photon emission CT myocardial perfusion imaging, ventilation-perfusion scanning, aortic and chest MR angiographic, and more specific x-ray and abdominal examinations may be appropriate as a third layer of testing, whereas MRI of the heart or coronary arteries and invasive testing such as transesophageal echocardiography or selective coronary angiography are not considered appropriate in these patients. Given the low risk of these patients, it is mandated to minimize radiation exposure as much as possible using advanced and appropriate testing protocols. The ACR Appropriateness Criteria® are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Abstract MP007: Epicardial Fat Thickness: Distribution of and Associations With Cardiovascular Risk Factors in the Framingham Heart Study

Introduction: High pericardial fat volume (fatVOL) is associated with excess cardiovascular disease (CVD), but analyses for true fat volume can be time-consuming and require specialized software. Linear epicardial fat thickness (fatTHK) can be measured quickly from cardiac magnetic resonance (MRI) images and may serve as a surrogate for fatVOL. We sought to determine the distribution and CVD risk factor correlates of high fatTHK and to compare fatTHK with fatVOL in a community-dwelling adult cohort. Methods: Participants were drawn from the Framingham Heart Study Offspring cohort (N=995, aged 65±9 years, 54% women) and underwent cardiac MRI (SSFP sequence) and multidetector CT during 2002-2005. Clinical and risk factor covariates were obtained at the preceding cycle 7 examination (1998-2001). FatVOL was determined from volumetric MDCT data. FatTHK was measured from the MRI 4-chamber view over the midlevel right ventricular free wall at end-diastole. A healthy referent subsample (N=328), free of major CVD risk factors, was used to determine sex-specific cut points for high fatTHK. Odds ratios for high (&gt;90th percentile) fatVOL and fatTHK versus common CVD risk factors were determined. Results: FatTHK was greater in men than women and increased with age in both sexes. FatTHK correlated with fatVOL at r=0.45 (p less than 0.001) High fatTHK was &gt;=16.0 mm in men and &gt;=13.3 mm in women, with 20.1% prevalence in men and 18.1 % in women. In both sexes, high fatVOL was associated ( Table ) with obesity, metabolic syndrome, dysglycemia, hypertension, prevalent CVD and hypertriglyceridemia. Similar associations, with slightly lower odds ratios, were seen for fatTHK. Conclusions: Greater fatTHK is associated with an excess burden of multiple CVD risk factors. Although correlation between linear fatTHK and true fatVOL was relatively modest, both measures appear to have similar associations with common CVD risk factors. FatTHK may be advantageous in that it can be determined quickly using standard MRI sequences for ventricular function. Table. Odds Ratios for High Pericardial Fat vs. Common CVD Risk Factors fatVOL: Men fatVOL: Women fatTHK: Men fatTHK: Women Obesity, BMI &gt;=30 kg/m2 4.34 (2.78–6.78) 3.13 (2.03–4.82) 2.52 (1.77–3.60) 2.62 (1.84–3.74) Metabolic Syndrome 3.72 (2.38–5.83) 2.60 (1.65–4.08) 2.59 (1.75–3.84) 2.21 (1.53–3.17) Dysglycemia, FPG &gt;=100 mg/dL 2.64 (1.72–4.06) 3.05 (1.98–4.68) 1.75 (1.22–2.50) 1.56 (1.10–2.23) Hypertension, S&gt;=140 or D&gt;=90 mmHg 2.51 (1.66–3.78) 1.96 (1.30–2.97) 2.10 (1.48–2.98) 1.58 (1.13–2.22) Prevalent CVD 1.94 (1.17–3.21) 2.48 (1.41–4.38) 1.73 (1.17–2.55) 1.83 (1.19–2.81) Triglycerides &gt;=150 mg/dL 1.89 (1.25–2.86) 2.21 (1.43–3.42) 1.64 (1.15–2.34) 1.98 (1.38–2.82) Low HDL: M&lt;40, W&lt;50 mg/dL 1.57 (1.03–2.38) 1.44 (0.91–2.28) 1.40 (0.98–1.99) 2.57 (1.80–3.67)

Evidence for prospective ECG-triggering coronary CT angiography in routine practice

Over the past decade, cardiac multidetector row CT (MDCT) has evolved, and the technology is poised to potentially alter the indications for diagnostic invasive coronary angiography (ICA) [1–10]. However, ionizing radiation concerns as related to increased cancer risks, initially applied to other organ systems [11, 12], have been translated to coronary CT angiography (CTA) and compared to ICA [13–17], while the dose dependent relation between low-radiation-dose exposure from cardiac procedures and subsequent risk of cancer has been reported [18]. Several strategies including ECG-triggered current modulation [19], lower tube voltage settings [13, 17, 20], and prospective ECG-triggering [21, 22] have progressively lowered patient radiation doses. One of the most applied approaches is prospective ECGtriggering [23, 24], where the exposure is confined to a predefined fraction of the time points of the cardiac cycle, rather than over the entire cycle. Depending on the details of the acquisition, the reduction in radiation dose can be as high as 80% [21, 22]. The effective dose of coronary CTA using prospective ECG-triggering (0.9–3.3 mSv) [2, 5] is comparable to, or lower than, diagnostic ICA (typical value of 7 mSv) [25]. However, there are unresolved concerns regarding diagnostic performance related to the limited phases of acquisition, and to date these methods have been most widely applied to patients with little risk of variations in cardiac cycle length and heart rates less than 70 beats per minute during the CT acquisition. In the current issue of the International Journal of Cardiovascular Imaging, Sun and Ng [26] performed a systematic review and meta-analysis of diagnostic value for coronary artery disease (CAD) using CTA with prospective ECG-triggering in comparison to ICA, and the authors also investigated the effective radiation dose. The 19 studies selected on primary selection criteria were reduced to fourteen that underwent the meta-analysis. Seven studies used singlesource 64-slice CT, four studies were performed with dual source 64-slice CT, two studies with 320-slice CT, and one with second generation of dual-source CT (128-slice). In 14 studies included in patient level (n = 910) analysis, pooled sensitivity for detection of significant CAD was 99% (95% CI: 98%, 100%) with specificity of 91% (95% CI: 88%, 94%) and the median negative predictive value (NPV) and positive predictive value (PPV) across studies were 94% (95% CI: 91%, 96%) and 99% (95% CI: 97%, 100%), respectively. Pooled positive (?LR) and negative (-LR) likelihood ratios were not reported at any of patient, vessel, or segment levels. Because observed heterogeneities were significant between 11 studies included in the vessel level (n = 3,531) and the segments level (n = 12,056) A. Salavati F. J. Rybicki (&) Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women’s Hospital, Harvard Medical School, RA024, 75 Francis Street, Boston, MA 02115, USA e-mail: frybicki@partners.org

Multidetector Row CT Detection of a Patent Foramen Ovale Causing Neurologic Deficits in an Adolescent: A Case Report

A patent foramen ovale (PFO) is a congenital cardiac lesion that can cause migraines with aura and stroke (1). Echocardiography is a first line diagnostic imaging modality for PFO (2). However, CT techniques have been improving, and some interesting papers demonstrating that PFO can be diagnosed by ECG-gated cardiac CT angiography have been published (3, 4). They reported that it is less sensitive to detect PFO by CT than by echocardiography. Recently, using cardiac multidetector row CT (MDCT), we detected PFO in a male adolescent patient. The PFO had been the hidden cause of a longstanding migraine.

Reference Values for Normal Pulmonary Artery Dimensions by Noncontrast Cardiac Computed Tomography

Background— Main pulmonary artery diameter (mPA) and ratio of mPA to ascending aorta diameter (ratio PA) derived from chest CT are commonly reported in clinical practice. We determined the age- and sex-specific distribution and normal reference values for mPA and ratio PA by CT in an asymptomatic community-based population. Methods and Results— In 3171 men and women (mean age, 51±10 years; 51% men) from the Framingham Heart Study, a noncontrast, ECG-gated, 8-slice cardiac multidetector CT was performed. We measured the mPA and transverse axial diameter of the ascending aorta at the level of the bifurcation of the right pulmonary artery and calculated the ratio PA. We defined the healthy referent cohort (n=706) as those without obesity, hypertension, current and past smokers, chronic obstructive pulmonary disease, history of pulmonary embolism, diabetics, cardiovascular disease, and heart valve surgery. The mean mPA diameter in the overall cohort was 25.1±2.8 mm and mean ratio PA was 0.77±0.09. The sex-specific 90th percentile cutoff value for mPA diameter was 28.9 mm in men and 26.9 mm in women and was associated with increase risk for self-reported dyspnea (adjusted odds ratio, 1.31; P =0.02). The 90th percentile cutoff value for ratio PA of the healthy referent group was 0.91, similar between sexes but decreased with increasing age (range, 0.82–0.94), though not associated with dyspnea. Conclusions— For simplicity, we established 29 mm in men and 27 mm in women as sex-specific normative reference values for mPA and 0.9 for ratio PA.

Evaluation of carcinoid heart disease using delayed enhancement imaging

We read with interest the case report by Martos et al. [1] entitled ‘‘Cardiac carcinoid: tricuspid delayed hyperenhancement on cardiac 64-slice multidetector CT and magnetic resonance imaging’’, published in the Irish Journal of Medical Science. Imaging characteristics of this rare disorder can be found in the literature; especially those features obtained using echocardiography and magnetic resonance imaging (MRI). The main morphological characteristics of the disease are thickening and restricted mobility of the tricuspid leaflets and subvalvular apparatus with consequent tricuspid stenosis and insufficiency. Although Martos et al. [2, 3] cite papers where characteristics of tricuspid-delayed enhancement were previously described, after careful reading we did not find any of them in the cited articles. Delayed-MRI enhancement can delineate zones of fibrous tissue 10–30 min after intravenous administration of gadolinium chelate contrast agent [4]. Similar depiction of scar and fibrous tissue can be obtained using computed tomography by delayed scanning after intravenous administration of iodinated contrast material [5]. In the case report Martos et al. describe delayed enhancement of tricuspid annulus in a patient with carcinoid heart disease, but, unfortunately, they did not give their explanation why they observed late enhancement in this region. We believe that in patients with carcinoid heart disease delayed enhancement should be seen only in endocardial region of the right cardiac chambers including tricuspid leaflets. This type of late enhancement would represent distribution of endocardial fibrous deposits that can be seen on pathological specimens. Considering that tricuspid annulus consists mainly of fibrous tissue, we believe that its late enhancement could be physiological, rather than related to carcinoid heart disease. For better understanding of the case report, we would like to add that figures 3B and 4A were mixed, so that figure 3B represents MDCT exam and figure 4A delayed enhancement on MRI examination. Furthermore, references 5 and 6 are the same with incorrectly spelled last name of the first author in the reference 6.

A comparison of radiation doses between state-of-the-art multislice CT coronary angiography with iterative reconstruction, multislice CT coronary angiography with standard filtered back-projection and invasive diagnostic coronary angiography

ObjectiveTo accurately compare the radiation dose between prospectively gated cardiac multidetector CT (with and without iterative reconstruction) and diagnostic invasive coronary angiography using the latest International Commission on Radiological Protection...

Applications of cardiac multidetector CT beyond coronary angiography

Noninvasive imaging of the coronary arteries using multidetector CT (MDCT) represents one of the most promising diagnostic imaging advances in contemporary cardiology. This challenging application has driven a rapid and impressive advancement in CT technology over the past 10 years; leading to increased spatial and temporal resolution, decreased scan times and substantial reductions in radiation dose. Recent technological improvements have not only improved the status of CT coronary angiography but have also enabled new functional myocardial applications that are gaining a foothold in clinical practice as adjuncts or replacements for conventional coronary angiographic studies. Wide-detector CT designs along with prospective ECG-triggered protocols have opened the possibility of performing multiple complementary myocardial measurements during a coronary CT exam with acceptable radiation and contrast exposure. In this Review, we discuss recent technical developments in cardiac MDCT and outline newly enabled noncoronary cardiac applications including viability assessment, myocardial perfusion and molecular imaging.

Pulmonary artery sling: an unexpected finding on cardiac multidetector CT

A 38-year-old woman with a 6-month history of breathlessness and intermittent central chest pain was referred for an ECG-gated cardiac CT examination. This excluded significant coronary artery disease, but revealed...

Multidetector-row computed tomographic evaluation of myocardial perfusion in reperfused chronic myocardial infarction: value of color-coded perfusion map in a porcine model

We aimed to develop color-coded CT perfusion maps (CPM) of infarcted myocardium and assess the utility of CPM in evaluating ischemic heart disease on a cardiac multi-detector CT (MDCT) in a porcine reperfused-myocardial-infarction model. Myocardial infarctions were induced by 30 min occlusions of the proximal left anterior descending coronary artery (LAD) in 17 healthy adult female pigs. First-pass and 5 min-delayed cardiac MDCTs were performed after 4 weeks of LAD occlusion. Myocardial CPMs were obtained by using the CPM program. Triphenyltetrazolium chloride (TTC)-staining was performed on the cardiac specimens. We analyzed the intermodality agreement on the size and location of the myocardial infarctions. TTC staining revealed myocardial infarction in 16 of 17 pigs, and 15 of these (94%) showed matched infarcts on the CPM and first-pass images. The areas of perfusion deficit noted in early arterial phase images and CPM coincided exactly with the areas of poor TTC staining in 12 of 15 pigs (80%). In the three remaining pigs, the areas of poor TTC staining were larger than those of a perfusion deficit demonstrated by either early arterial phase images or CPM. The agreement between these tests is calculated to be moderate to good (k = 0.736, P < 0.05). Ten myocardial segments in 4 of the 15 pigs (27%) with hypoattenuated myocardium showed a delayed enhancement on the 5 min-delayed images. Contrast-enhanced MDCT was useful and accurate in detecting chronic myocardial infarction; CPM was helpful in visualizing the infarcted myocardium.

Method for Automatic Tube Current Selection for Obtaining a Consistent Image Quality and Dose Optimization in a Cardiac Multidetector CT

ObjectiveTo evaluate a quantitative method for individually adjusting the tube current to obtain images with consistent noise in electrocardiogram (ECG)-gated CT cardiac scans.Materials and MethodsThe image noise from timing bolus and cardiac CT scans of 80 patients (Group A) who underwent a 64-row multidetector (MD) CT cardiac examination with patient-independent scan parameters were analyzed. A formula was established using the noise correlation between the timing bolus and cardiac scans. This formula was used to predict the required tube current to obtain the desired cardiac CT image noise based on the timing bolus noise measurement. Subsequently, 80 additional cardiac patients (Group B) were scanned with individually adjusted tube currents using an established formula to evaluate its ability to obtain accurate and consistent image noise across the patient population. Image quality was evaluated using score scale of 1 to 5 with a score of 3 or higher being clinically acceptable.ResultsUsing the formula, we obtained an average CT image noise of 28.55 Hounsfield unit (HU), with a standard deviation of only 1.7 HU, as opposed to a target value of 28 HU. Image quality scores were 4.03 and 4.27 for images in Groups A and B, respectively, and there was no statistical difference between the image quality scores between the two groups. However, the average CT dose index (CTDIvol) was 30% lower for Group B.ConclusionAdjusting the tube current based on timing bolus scans may provide a consistent image quality and dose optimization for cardiac patients of various body mass index values.