Multidetector-row Computed Tomography Coronary Angiography Research Articles

Association between plasma levels of PCSK9 and the presence of coronary artery disease in Japanese.

The ability of pro-protein convertase subtilisin/kexin type 9 (PCSK9) levels to predict the presence or severity of coronary artery disease (CAD) remains controversial. The purpose of this study was to investigate these associations. We enrolled 393 patients who were clinically suspected to have CAD or who had at least one cardiac risk factor and underwent multidetector-row computed tomography coronary angiography. The presence of CAD (≥50% coronary stenosis), the number of significantly stenosed coronary vessels, and plasma levels of PCSK9 by ELISA were analyzed. Plasma PCSK9 levels (log-transformed data) were significantly associated with the presence of CAD. Next, we divided the patients into two groups (non-statin and statin groups) according to statin treatment. PCSK9 levels in the non-statin group were significantly lower than those in the statin group. There were no significant differences in PCSK9 levels between the absence and presence of CAD in the statin group. However, in the non-statin group, PCSK9 levels in patients with CAD were significantly higher than those in patients without CAD. PCSK9 levels, in addition to age, gender, BMI, DM and HDL-C, were independently associated with the presence of CAD by a multivariable analysis. In conclusion, our results demonstrated that plasma PCSK9 levels may be a marker for evaluating the presence of CAD.

Safety of Landiolol Hydrochloride as a Premedication for Producing an Appropriate Heart Rate for Multidetector-Row Computed Tomography Coronary Angiography.

BackgroundWe evaluated the safety of a bolus injection of landiolol hydrochloride, an ultrashort-acting β1-selective antagonist, as a premedication prior to multidetector-row computed tomography coronary angiography (CTA).MethodsThe subjects consisted of 176 patients (M/F = 64:112, 67 ± 11 years) who had heart rate (HR) at rest ≥ 70 beats/min (bpm) and underwent CTA. Systolic/diastolic blood pressure (SBP/DBP) and HR were measured before and after the administration of landiolol.ResultsSBP/DBP and HR upon entry to the CT room were 136 ± 17/80 ± 11 mm Hg and 83 ± 10 bpm, respectively. HR was significantly reduced at the time of CTA scan (62 ± 7 bpm). Next, we divided the patients into three groups according to HR upon entry to the CT room: 70 - 79 bpm (n = 76), 80 - 89 bpm (n = 60) and ≥ 90 bpm (n = 40). HR at the time of CTA scan was significantly lower than that upon entry to the CT room in all three groups: 70 - 79 bpm (74 ± 3 bpm upon entry to the CT room to 61 ± 6 bpm at the time of CAT scan), 80 - 89 bpm (84 ± 3 to 63 ± 7 bpm) and ≥ 90 bpm (98 ± 6 to 65 ± 7 bpm). Although SBP/DBP was significantly decreased after the CTA scan (123 ± 18/72 ± 12 mm Hg), landiolol had no severe adverse events throughout CTA.ConclusionIn conclusion, a bolus injection of landiolol reduced HR by about 20 bpm without any severe adverse effects. Thus, a bolus injection of landiolol hydrochloride may be a suitable pretreatment for controlling HR in CTA.

Prevalence and characteristics of coronary artery anomalies in an adult population undergoing multidetector-row computed tomography for the evaluation of coronary artery disease.

BackgroundCongenital coronary anomalies are uncommon with an incidence ranging from 0.17 % in autopsy cases to 1.2 % in angiographically evaluated cases. The recent development of ECG–gated multi–detector row computed tomography (MDCT) coronary angiography allows accurate and noninvasive depiction of coronary artery anomalies.MethodsThis retrospective study included 2572 patients who underwent coronary 64-slice MDCT coronary angiography from January 2008 to March 2012. Coronary angiographic scans were obtained with injection of 80 ml nonionic contrast medium. Retrospective gating technique was used to synchronize data reconstruction with the ECG signal. Maximum intensity projection, multi-planar reformatted, and volume rendering images were derived from axial scans.ResultsOf the 2572 patients, sixty (2.33 %) were diagnosed with coronary artery anomalies (CAAs), with a mean age of 53.6 ± 11.8 years (range 29–80 years). High take-off of the RCA was seen in 16 patients (0.62 %), of the left main coronary artery (LMCA) in 2 patients (0.08 %) and both of them in 2 patients (0.08 %). Separate origin of the left anterior descending artery (LAD) and left circumflex artery (LCx) from left sinus of Valsalva (LSV) was found in 15 patients (an incidence of 0.58 %). In 9 patients (0.35 %) the right coronary artery (RCA) arose from the opposite sinus of Valsalva with a separate ostium. In 6 patients (0.23 %) an abnormal origin of LCX from the right sinus of Valsalva (RSV) was found with a further posterior course within the atrioventricular groove. A single coronary artery was seen in 3 patients (0.12 %). It originated from the right sinus of Valsalva in one patient and from LSV in two patients. In two other patients (0.08 %) the left coronary trunk originated from the RSV with separate ostium from the RCA. LCA originating from the pulmonary artery was found in one patient (0.04 %). A coronary artery fistula, which is a termination anomaly, was detected in 4 patients (0.15 %).DiscussionAlthough these anomalies, which are remarkably different from the normal structure, exist as early as birth, they are incidentally encountered during selective angiography or at autopsy. The incidence in reported angiographic series ranges from 0.6 % to 1.3 %. Variations in the frequency of primary congenital coronary anomalies may possibly have a genetic background. The largest angiographic series of 126595 patients, by Yamanaka and Hobbs, reported a 1.3 % incidence of anomalous coronary artery.ConclusionThe results of this study support the use MDCT coronary angiography as a safe and effective noninvasive imaging modality for defining CAAs in an appropriate clinical setting, providing detailed three-dimensional anatomic information that may be difficult to obtain with invasive angiography.

Safety and Efficacy of a Bolus Injection of Landiolol Hydrochloride as a Premedication for Multidetector-Row Computed Tomography Coronary Angiography

We evaluated the safety and efficacy of a bolus injection of landiolol hydrochloride, an ultrashort-acting β1-selective antagonist, as an additional treatment after premedication with an oral β-blocker to reduce heart rate prior to multidetector-row computed tomography (MDCT) coronary angiography (CAG). A total of 458 patients who underwent MDCT CAG were retrospectively enrolled. Image quality and hemodynamic parameters were compared in patients before and after approval of landiolol hydrochloride. If heart rate reduction was insufficient after premedication with an oral β-blocker, a bolus injection of landiolol hydrochloride (n=66) or other drugs (n=30) was used. The percentage of evaluable images per segment in patients after approval of landiolol (99.3%) was greater than that in patients before approval of landiolol (97.4%, P<0.01). Heart rates before scanning in patients receiving landiolol hydrochloride were similar to those receiving other drugs. Heart rate was significantly reduced approximately 5 min after injection of landiolol hydrochloride and increased shortly. No decrease in systolic blood pressure or other adverse effects was observed. Bolus injection of landiolol hydrochloride sufficiently reduced heart rate without significantly reducing systolic blood pressure and produced a high percentage of evaluable images, suggesting that bolus injection of landiolol hydrochloride as an additional pretreatment is feasible in MDCT CAG.

Non-Coronary Applications of Cardiac Computed Tomography

Multi-detector row computed tomography coronary angiography (MDCT-CA) has been incorporated in the diagnostic algorithm of patients with suspected coronary artery disease due to its significant negative predictive value. In addiction, volume acquisition and ECG-cardiac gating allow submillimeter reconstructions in all possible angles at different time positions within the cardiac cycle. This produces a favorable scenario for the morphological and functional evaluation, and opens the possibility of using this technique in other territories; most of them can be evaluated during the study of the coronary arteries without requiring additional contrast agents or radiation. The capability of the method for the simultaneous evaluation or morphology and function allows a comprehensive approach of wide scope of conditions within the same study.

Prognostic outcome of routine clinical noninvasive multidetector-row computed tomography coronary angiography in patients with suspected coronary artery disease: a 2-year follow-up study

The aim of the study was to assess the prognostic value of multidetector-row CT coronary angiography (MDCT-CA) in patients with suspected coronary artery disease (CAD) in a routine clinical context. A total of 125 patients (82 men, age 57.4±10.3 years) with suspected CAD underwent MDCT-CA. All patients were assessed for cardiovascular risk factors, symptoms and coronary calcium score. A 2-year follow-up study for the occurrence of major adverse cardiac events was performed. According to the Morise pretest score, 76 patients (60.8%) were at intermediate risk. Patients with suspected CAD presented the following prognostic outcome (p<0.0001): in 41 patients with normal coronary arteries at MDCT-CA, the event rate was 0%; five of 49 patients with nonobstructive CAD had major cardiac events; two of 35 patients with obstructive CAD suffered cardiac death and 19 underwent revascularisation. At multivariate analysis, the presence of obstructive CAD is the only significant independent prognostic variable (hazard ratio, 10.1393; 95% confidence interval 3.2189-31.9379; p<0.0001). Routine clinical MDCT-CA provides an excellent prognostic value at 2-year follow-up in patients with normal coronary arteries. The cardiac event rate increases with CAD severity.

Anomalous Double Right Coronary Arteries

To evaluate the characteristic multidetector-row computed tomography (MDCT) findings of anomalous double right coronary arteries (RCAs), an extremely rare variant. During a 3-year period, 2569 patients with chest pain underwent MDCT coronary angiography. Five patients (0.2%) with anomalous double RCAs were found (mean age, 66 years; range, 43-81 years; 3 women). The location and number of orifice, anatomical distribution of the RCA and its branches, and presence of atherosclerosis were analyzed. All the 5 cases of double RCAs originated from the right sinus of Valsalva and could be classified into 3 types according to the characteristics. One patient (type 1) had a double RCA arising from 2 separated orifices in the right sinus of Valsalva; another patient (type 2) had 2 separate RCAs originating from a common orifice in the sinus of Valsalva; the other 3 patients with double RCAs (type 3) had a common main RCA in the sinus of Valsalva with a proximal bifurcation, like the usual left coronary arterial system. Our data showed that although a double RCA is a rare anomaly, it is easily detected using MDCT and can be classified into 3 types.

Choice strategy of different dose-saving protocols in 64-slice MDCT coronary angiography

Multidetector-row computed tomography coronary angiography (MDCT-CA) produces high-level radiation dose because of submillimetre slice thickness and short scan time. As a result, manufacturers have produced different dose-saving protocols that may, however, reduce image quality and thus diagnostic accuracy. The aim of our study was to assess the diagnostic quality of MDCT-CA using different dose-saving protocols. Between April and August 2008, we examined 65 patients with 64-slice MDCT-CA: 6/65 using the step-and-shoot dose-saving protocol, 45/65 the cardiac dose right protocol and 14/65 using a standard protocol. Image quality was evaluated on a per-patient and per-segment basis, and the effective dose of each protocol was recorded. In the per-patient analysis, image quality was excellent in 100% of the step-and-shoot protocols, in 91.1% of the cardiac dose right protocols and in 85.8% of the standard protocols. Effective dose to the patient considering the whole study (i.e. scout, calcium score, triggering and MDCT-CA) was 20.49 mSv in the standard protocol, 14.8 mSv in the cardiac dose right protocol and 6.63 mSv in the step-and-shoot protocol. The radiologist should apply the appropriate protocol in relation to the clinical indications, type of patient and information required in order to spare as much dose as possible while maintaining high image quality.

Diagnostic accuracy of MDCT coronary angiography in patients referred for heart valve surgery

The aim of our study was to evaluate the role of multidetector-row computed tomography (MDCT) in patients referred for heart valve surgery. We studied the diagnostic performance of CT coronary angiography (CTCA) compared with conventional coronary angiography (CCA) before valve surgery. During a 13-month period, 55 consecutive patients under evaluation for aortic (40/55) or mitral valve (15/55) disease before potential valve replacement underwent CTCA using a 64-detector-row scanner within 2 months of CCA for comparative purposes. All 17 major coronary artery segments were evaluated by one observer and compared with the reference standard. Patient-based, vessel-based and segment-based analyses of the data were performed. Prevalence of significant coronary artery disease, defined as having at least one stenosis >/=50% per patient, was 36%. On a patient-based analysis, sensitivity, specificity and positive and negative predictive values were 100%, 91%, 83% and 100%, respectively. The diagnostic accuracy of 64-row CTCA for ruling out the presence of significant coronary stenoses in patients undergoing valve surgery is excellent and allows CTCA to be used as a gatekeeper for invasive CCA in these patients. MDCT is a necessary preoperative examination that provides useful information for identifying potential operative complications of surgical procedures.

Assessment of left main coronary artery atherosclerotic burden using 64-slice CT coronary angiography: correlation between dimensions and presence of plaques

The aim of this study was to correlate left main (LM) coronary artery dimensions with the presence of atherosclerosis by multidetector-row computed tomography (MDCT) coronary angiography (CA) and to assess coronary atherosclerotic plaques with a semiquantitative method. Sixty-two consecutive patients (41 men, mean age 60+/-11) with suspected coronary artery disease underwent 64-MDCT coronary angiography. LM dimensions (length, ostial and bifurcation diameters), quantitative [location, Hounsfield unit (HU) attenuation] and qualitative (composition, shape) analysis of plaques within the LM were performed. All patients underwent conventional CA. Thirty patients (mean age 55+/-10) without plaques in the LM presented the following average dimensions: length 10.6+/-6.1 mm, ostial diameter 5.5+/-0.7 mm, bifurcation diameter 4.9+/-0.9 mm. LM plaques (n=36) were detected in 32 patients (mean age 64+/-10) with the following LM average dimensions: length 11.3+/-4.0 mm, ostial diameter 6.0+/-1.2 mm and bifurcation diameter 6.0+/-1.2 mm. Plaques were calcified (40%, mean attenuation 742+/-191 HU), mixed (43%, mean attenuation 387+/-94 HU) or noncalcified (17%, mean attenuation 56+/-14 HU) and were frequently eccentric (77%). Age was significantly different in the two groups (p<0.05). LM diameters of patients with plaques were improved (p<0.05). A moderate correlation was found between the LM bifurcation diameter and the corresponding plaque area (r=0.56). Significant conventional CA lesions of the LM were present in just three patients (5%). Increased LM diameters are associated with the presence of atherosclerosis. MDCT CA indicates relevant features of LM atherosclerotic burden, as rupture and subsequent thrombosis of vulnerable plaques may develop from lesions characterised as nonsignificant at conventional CA.

Computed Tomographic Coronary Angiography for Diagnosing Stable Coronary Artery Disease A Cost-Utility and Cost-Effectiveness Analysis

To evaluate the lifetime potential benefits and cost-effectiveness of using 64 multidetector-row computed tomography coronary angiography (CTCA) as a noninvasive imaging modality for patients at risk for coronary artery disease (CAD). A decision and cost-effective analysis using a Markov model was performed to compare 4 strategies: (1) no examination, (2) routine coronary angiography (CAG), (3) CTCA, or (4) medication without CAG or CTCA in persons at risk for stable CAD. Compared with the no examination and no treatment strategies, CTCA gained 0.551 quality-adjusted life-years (QALYs) with an incremental cost-effectiveness ratio (ICER) of US$15,581 (in 2007) per QALY. Routine CAG gained 0.012 QALYs compared with the CTCA strategy, with an ICER of US$445,276 per QALY. Using CTCA as the first-line examination for 60-year-old men at risk for stable CAD achieved gains of QALY comparable to that of routine CAG, but at a lower cost.

Congenital coronary artery anomalies: Diagnosis with 64 slice multidetector row computed tomography coronary angiography: A single‐centre study

Retrospective review of the congenital coronary artery (CA) anomalies detected by a 64-slice multidetector row computed tomographic (MDCT) angiography. The type of the anomaly, imaging characteristics, clinical relevance and the superiority of the MDCT over conventional coronary angiography are discussed. Multidetector row computed tomographic coronary angiography was carried out by the usual technique with 70 cc of non-ionic contrast agent and retrospective electrocardiogram gating. The volume data obtained were reconstructed in axial plane, along with volume-rendered three-dimensional reconstruction and virtual angioscopy in selected patients. The images were analysed by a radiologist, experienced in cardiac CT, and an experienced cardiologist. A retrospective review of the records was carried out, and subjects with congenital coronary anomalies were included in the study. Between 15 November 2005 and 27 February 2007, 1495 MDCT coronary angiograms were carried out. Eleven of them were found to have coronary anomalies. Five had absent left main CA. Two had interarterial course of the left main CA artery passing in between the right ventricular outflow tract and the root of aorta. In one patient, there was aberrant origin of right CA from the left aortic sinus with subsequent interarterial course and another one had aberrant origin of circumflex artery from the right aortic sinus. One patient each of congenitally absent circumflex artery and atresia of the right CA were found. Sixty-four slice MDCT coronary angiography provided accurate depiction of anomalous vessel origin and course along with the complex anatomical relation with the adjacent structures. CT can be considered as a first-line imaging method for delineating coronary arterial anomalies.

ECG-Edit Function in Multidetector-Row Computed Tomography Coronary Arteriography for Patients With Arrhythmias

ECG-gating is necessary for cardiac computed tomography, but is not suitable for arrhythmias, so the aim of this study was to evaluate the usefulness of the ECG-edit function for this purpose. Of 1,221 patients undergoing 64-row multidetector-row computed tomography coronary angiography (coronary MDCT), 123 patients (28 atrial fibrillation (Af), 39 premature atrial contractions (PAC), 42 premature ventricular contractions (PVC), 3 PAC + PVC, 10 sinus arrhythmias (SA), and a second-degree atrioventricular block (2 degrees AVB)) had arrhythmias necessitating the ECG-edit function. Short R-R interval was deleted and mid-diastolic phases were selected from the long R-R intervals using the "R+absolute time" method. In the present study, the reconstructed images were evaluated using a triple-grade scale A-C, representing excellent, acceptable, and unacceptable image quality. Image quality, categorized as A, B and C, respectively, was 50%, 36% and 14% for the 28 patients with Af; 56%, 36% and 8% for the 39 PAC patients, and 65%, 33% and 2% in the 42 PVC patients. None of the scans of the PAC + PVC, SA, and 2 degrees AVB patients was ranked as C. The ECG-edit function is useful for reconstructing coronary MDCT images in many arrhythmias, and provides clinically acceptable images in most cases.

Assessing Culprit Lesions and Active Complex Lesions in Patients With Early Acute Myocardial Infarction by Multidetector Computed Tomography

Accurate, non-invasive characterization of culprit lesions in patients after acute myocardial infarction (AMI) remains challenging. In this prospective study, multidetector row computed tomography (MDCT) is used to assess culprit and active complex lesions in patients early after AMI. We enrolled 103 patients with first non ST-elevation AMI who underwent 64-slices MDCT and conventional coronary angiography (CCAG). The definition of culprit lesion, stable non-culprit lesions and non-culprit active complex lesions was based on the findings of CCAG. The lesions were analyzed with MDCT data. In culprit lesions (n=103), luminal artery stenosis, remodeling index, plaque area and burden were significantly higher than non-culprit lesions (n=129). Multivariate discriminant analysis showed that MDCT density could discriminate culprit from non-culprit lesions. Receiver-operator characteristic curve analysis identified the optimal cutoff value of lesion density for discrimination between culprit and non-culprit lesion as 49.6 Hounsfield units (HU); this value was associated with a sensitivity, specificity and accuracy of 88.4%, 87.4%, and 87.9%, respectively. The MDCT in the stable non-culprit lesions (81.8+/-15.5 HU) was significantly higher than that in culprit lesions or non-culprit active complex lesions (33.2+/-13.8 and 48.3+/-15.7 HU, p<0.001). MDCT can predict culprit lesions in patients early after AMI, and identify multiple complex lesions.

Impaired left ventricular function has a detrimental effect on image quality in multi-detector row CT coronary angiography

To determine whether there is a relationship between left ventricular (LV) haemodynamic parameters, circulation times, and arterial contrast opacification that might affect the image quality of computed tomography (CT) coronary angiography. Thirty-six patients were included in the study: 18 with cardiomyopathy (CM) and LV dilatation of suspected ischaemic aetiology [age 57.9+/-13.7 years, range 30-77 years; 14 male, four female; body mass index (BMI)=27.7+/-4.5, range 25.5-31.8] and 18 controls (age 62.3+/-9.4 years, range 47-89 years; 10 male, eight female; BMI 27.8+/-6.6; range 19.2-33.6). Coronary artery image quality was assessed using a three-point visual scale; contrast medium circulation times, aortic root contrast attenuation, and LV functional parameters were studied. Visually reduced contrast opacification impaired image quality more often in the CM group than the control group (27.4 versus 5.1%). A total of 55.6% CM patients had a contrast transit time ranging from 30-75 s; the number of "unassessable" segments increased with increasing transit time conforming to a fitted quadratic model (R2=0.74). The relationship between LV ejection fraction and contrast attenuation may also conform to a quadratic model (R2=0.71). LV haemodynamics influence coronary artery opacification using cardiac CT, and users imaging this subgroup must do so with the knowledge of this potential pitfall. The results indicate the need for further studies examining CT protocols in this clinical subgroup.

Multi-detector row CT coronary angiography in patients with cardiomyopathy – initial single-centre experience

To evaluate the diagnostic accuracy of computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients with cardiomyopathy (CM). Eighteen patients with CM were approached to undergo CT coronary angiography to evaluate the use of this technique for investigating the presence of significant coronary artery disease (CAD), and also to compare the findings with catheter angiography. On a segment-by-segment analysis the sensitivity, specificity, positive and negative predictive values in the CM group were 66.7, 96.5, 40 and 98.8%, respectively, with 100% accuracy in "whole-patient terms". Non-invasive, 16-detector row CT coronary angiography in patients with presumed CM would seem to be a useful clinical tool for the exclusion of significant coronary artery disease. However, the presence of suboptimal contrast opacification in this patient group means that the implication of these results must be interpreted with caution.

Multidetector-Row Computed Tomography Coronary Angiography Optimization of Image Reconstruction Phase According to the Heart Rate

To optimize the image reconstruction phase of multidetector-row computed tomography (MDCT) coronary angiography according to the heart rate is crucial. Scan data were reconstructed for 10 different phases in 58 sequential patients who underwent 8-row cardiac MDCT. The obtained images were scored and compared in terms of motion artifacts and visibility of the vessels, and moreover, ECG record-based evaluations were added for clarification of the temporal relationships among these 10 phases. In the cases with lower heart rates (<65 beats/min), the best quality images were obtained when the end of the image reconstruction phase was positioned at the peak of the P wave. In some cases with higher heart rates (>65 beats/min), they were obtained in the late systolic period. As the heart rate increased, the optimal image reconstruction phase changed from mid diastole to late systole. However, it is recommended to try to decrease the heart rate of patients before data acquisition.

Giant coronary artery aneurysm secondary to Kawasaki disease: diagnosis in an adult by multi-detector row CT coronary angiography

We present the case of an adult female patient with a giant coronary artery aneurysm secondary to Kawasaki disease diagnosed for the first time, as far as the authors are aware, on multi-detector row computed tomography (MDCT). The long-term complications relate to the persistence of these aneurysms with giant coronary aneurysms having the lowest regression rate, the highest risk of stenosis and strongest association with myocardial infarction. MDCT coronary angiography represents an ideal, alternative non-invasive imaging modality for the diagnosis and follow-up of the coronary arterial complications of Kawasaki disease, thereby avoiding invasive coronary imaging, and its use in the management algorithm should be considered. We also aim to contribute to the expanding clinical role of MDCT coronary imaging.

16-Detector row computed tomographic coronary angiography in patients undergoing evaluation for aortic valve replacement: comparison with catheter angiography

To evaluate the diagnostic accuracy of 16-detector row computed tomography (CT) in assessing haemodynamically significant coronary artery stenoses in patients under evaluation for aortic stenosis pre-aortic valve replacement. Forty consecutive patients under evaluation for severe aortic stenosis and listed for cardiac catheterization before potential aortic valve replacement underwent coronary artery calcium (CAC) scoring and retrospective electrocardiogram (ECG)-gated multi-detector row computed tomographic coronary angiography (MDCTA) using a GE Lightspeed 16-detector row CT within 1 month of invasive coronary angiography (ICA) for comparative purposes. All 13 major coronary artery segments of the American Heart Association model were evaluated for the presence of > or =50% stenosis and compared to the reference standard. Data were analysed on a segment-by-segment basis and also in "whole patient" terms. A total of 412/450 segments from 35 patients were suitable for analysis. The overall accuracy of MDCTA for detection of segments with > or =50% stenosis was high, with a sensitivity of 81.3%, specificity 95.0%, positive predictive value (PPV) 57.8%, and negative predictive value (NPV) 98.4%. On a "whole-patient" basis, 100% (19/19) of patients with significant coronary disease were correctly identified and there were no false-negatives. Excluding patients with CAC >1000 from the analysis improved the accuracy of MDCTA to: sensitivity 90%, specificity 98.1%, PPV 60%, NPV 99.7%. Non-invasive 16-detector row MDCTA accurately excludes significant coronary disease in patients with severe aortic stenosis undergoing evaluation before aortic valve replacement and in whom ICA can therefore be avoided. Its segment-by-segment accuracy is improved further if CAC>1000 is used as a gatekeeper to MDCTA.

Multi–Detector Row CT Coronary Angiography: Influence of Reconstruction Technique and Heart Rate on Image Quality

To prospectively evaluate to what extent image quality in 16-detector row computed tomographic (CT) coronary angiography is a function of the heart rate and the image reconstruction technique used. A total of 70 patients (49 men, 21 women; mean age, 59.1 years +/- 5.8 [standard deviation]) consecutively underwent multi-detector row CT coronary angiography; 49 patients additionally underwent coronary angiography. Image reconstruction was based on both relative and absolute timing. A total of 20 equidistant relative and absolute image reconstructed intervals were assessed by applying a four-step grading scale. Cluster and discrimination analysis, Spearman correlation analysis, and Wilcoxon and chi2 tests were used for statistical analysis. Institutional review board approval and written informed consent were obtained. Though significantly (P < .001) better image quality was observed for image reconstruction based on absolute timing and in patients with lower heart rates, influence on diagnostic accuracy was not significant. Irrespective of the reconstruction technique used, best image quality was observed in patients with a low heart rate for middiastolic reconstruction intervals (starting points: 61% of R-R interval [range, 40%-75%] and 599.3 msec after R [range, 450-840 msec]) and in patients with a high heart rate for end-systolic or early-diastolic intervals (starting points: 27.3% of R-R interval [range, 10%-45%] and 202.3 msec after R [range, 82-336 msec]). With regard to the vessel section and reconstruction technique, cutoff heart rates of the intervals were 64.0-68.5 beats per minute. Patients with stenoses of more than 50% were identified with 86% sensitivity and specificity, and there was no significant difference between relative and absolute timing (P = .99). In multi-detector row CT coronary angiography, image quality depends on the choice of a suited reconstruction interval. In patients with high heart rates, the best image quality can be obtained with end-systolic and early-diastolic intervals; in patients with low heart rates, the best results are achieved with middiastolic intervals.