Nathan Peled

Usefulness of 64-Slice Cardiac Computed Tomographic Angiography for Diagnosing Acute Coronary Syndromes and Predicting Clinical Outcome in Emergency Department Patients With Chest Pain of Uncertain Origin

Background— Multidetector computed tomography (MDCT) has high diagnostic value for detecting or excluding coronary artery stenosis. We examined performance characteristics of MDCT for diagnosing or excluding an acute coronary syndrome in patients presenting to the emergency department (ED) with possible ischemic chest pain and examined relation to clinical outcome during a 15-month follow-up period. Methods and Results— We prospectively studied 58 patients (56±10 years of age, 36% female) with chest pain possibly ischemic in origin and no new ECG changes or elevated biomarkers. The patients underwent 64-slice contrast-enhanced MDCT, which showed normal coronary vessels (no or trivial atheroma) in 15 patients, nonobstructive plaque in 20 (MDCT-negative patients), and obstructive coronary disease (≥50% luminal narrowing) in 23 (MDCT-positive group). By further investigation (new elevation of cardiac biomarkers, abnormal myocardial perfusion scintigraphy and/or invasive angiography), acute coronary syndrome was diagnosed in 20 of the 23 MDCT-positive patients (ED MDCT sensitivity 100% [20/20], specificity 92% [35/38], positive predictive value 87% [20/23], negative predictive value 100% [35/35]). During a 15-month follow-up period, no deaths or myocardial infarctions occurred in the 35 patients discharged from the ED after initial triage and MDCT findings. One patient underwent late percutaneous coronary intervention (late major adverse cardiovascular events rate, 2.8%). Overall, ED MDCT sensitivity for predicting major adverse cardiovascular events (death, myocardial infarction, or revascularization) during hospitalization and follow-up was 92% (12/13), specificity was 76% (34/45), positive predictive value was 52% (12/23), and negative predictive value was 97% (34/35). Conclusions— We found that 64-slice cardiac MDCT is a potentially valuable diagnostic tool in ED patients with chest pain of uncertain origin, providing early direct noninvasive visualization of coronary anatomy. ED MDCT had high positive predictive value for diagnosing acute coronary syndrome, whereas a negative MDCT study predicted a low rate of major adverse cardiovascular events and favorable outcome during follow-up.

Noninvasive evaluation of arterial grafts with newly released multidetector computed tomography

BACKGROUNDnHigh-quality postoperative imaging of bypass conduits is essential when evaluating different types of conduits, anastomoses, and surgical techniques. We investigated the potential value of the newest generation of multidetector-row computer tomographic scanners in assessing bypass grafts.nnnMETHODSnFrom June to September 2002, 14 patients underwent scanning with a newly released 16-slice computed tomographic scanner (Mx8000 IDT; Philips Medical Systems) after coronary artery bypass grafting. Four patients had had minimally invasive direct coronary artery bypass grafting and 3, redo coronary artery revascularization. Contrast-enhanced computed tomographic angiography was performed using retrospective electrocardiographic gating. Scan length was 22 to 30 cm, and total scan time was 27 to 37 seconds.nnnRESULTSnOf the 14 patients, 8 were scanned within 1 week after operation and 6, 1 month to 12 months postoperatively. Average heart rate during the scan was 82 beats per minute (range, 60 to 97 beats per minute), and all patients were able to hold their breath for the required time. Thirty conduits were studied: 26 arterial (18 in situ left and right internal mammary artery grafts, five free right internal mammary and radial artery grafts, and three in situ right gastroepiploic artery grafts) and four vein grafts. Excellent visualization of all 30 grafts was achieved. Thirty-four of the 35 distal anastomoses were patent; one vein graft was occluded.nnnCONCLUSIONSnThis new technology is a promising noninvasive measure to evaluate patency of bypass conduits, including the gastroepiploic artery where catheterization is usually difficult. The ability to display the vessel wall as well as its lumen might distinguish radial artery spasm from intimal hyperplasia. The superb resolution and increased scan length required to cover the entire internal mammary artery grafts-from origin to distal anastomoses-can be achieved easily in a single breath-holding owing to the increased number of slices per rotation and shortening of the gantry rotation time.

Combined Assessment of Coronary Anatomy and Myocardial Perfusion Using Multidetector Computed Tomography for the Evaluation of Coronary Artery Disease

Multidetector computed tomography (MDCT) is increasingly used as an alternative to invasive coronary angiography. Although computed tomographic coronary angiography (CTCA) has been validated against invasive coronary angiography and nuclear myocardial perfusion imaging, the potential of MDCT to evaluate perfusion has not been fully explored. We sought to (1) develop a new technique for quantitative assessment of myocardial enhancement based on analysis of MDCT images acquired for CTCA, (2) identify the underlying causes of myocardial hypoenhancement detected by MDCT, and (3) determine the added diagnostic value of the MDCT perfusion index when combined with CTCA. We studied 84 patients undergoing clinical CTCA (64 patients with invasive coronary angiogram and a control group of 20 patients). MDCT perfusion index was calculated from x-ray attenuation measured in 16 myocardial segments. Hypoenhancement was automatically detected using comparisons with the normal range obtained in the control group, and its added value was determined against invasive coronary angiographic findings combined with known previous myocardial infarction. Myocardial hypoenhancement was detected in 29 of 64 patients in 47 vascular territories, of which 36 (77%) were abnormal by the reference technique. Of these 36 abnormalities, 10 (28%) were associated with previous myocardial infarction, whereas 26 (72%) corresponded to significant coronary stenosis. The addition of MDCT perfusion index to CTCA improved its diagnostic accuracy (sensitivity 0.87 to 0.96, accuracy 0.84 to 0.88, despite a decrease in specificity 0.79 to 0.68). In conclusion, myocardial hypoenhancement is a potentially valuable addition to MDCT evaluation of coronary artery disease without additional cost in radiation dose or contrast load.

Cardiac computed tomographic angiography for risk stratification and prediction of late cardiovascular outcome events in patients with a chest pain syndrome

BACKGROUNDnContrast-enhanced multidetector cardiac computed tomographic angiography (CCTA) has high sensitivity and specificity for diagnosing anatomic coronary stenoses, but its role in predicting late clinical outcome events has not been well studied.nnnMETHODSnWe examined predictive value of CCTA for late major adverse cardiovascular (CV) outcome events (MACE)(CV death, myocardial infarction, myocardial revascularization) (follow-up 18.2+/-6.3, range 9-30 months) in 545 consecutive symptomatic patients (368 (68%) men, 177 (32%) women) with clinical suspicion, but without previously diagnosed, coronary artery disease (CAD) who underwent 40- or 64-channel CCTA.nnnRESULTSnMACE occurred in 53/545 (9.7%) patients (early 30 day CCTA-driven events excluded): CV death/myocardial infarction in 3/327 (0.9%) patients with no coronary luminal narrowing >25% (group 1), in 3/127 (2.4%) with >or=1 luminal narrowing(s) of 26-69% (group 2) and in 9/91 (9.9%) with >or=1 coronary luminal narrowing(s) of >or=70% (group 3) (p<0.0001). CV death/myocardial infarction/revascularization occurred in 5/327 (1.5%) group 1 patients, 19/127 (14.9%) group 2 and 29/91 (31.9%) group 3 (p<0.0001). Multivariate analysis (adjusting for age, gender, coronary risk factors and coronary calcium score) identified CCTA stenosis (>25%) as a powerful independent predictor of MACE (HR 10.9, 95%CI 4.1-29.0, p<0.0001).nnnCONCLUSIONSnCCTA was useful to predict late clinical outcome events in patients undergoing evaluation of a chest pain syndrome.

Computer-aided simple triage (CAST) for coronary CT angiography (CCTA)

PurposeFollowing a recent introduction of computer-aided simple triage (CAST) as a new subclass of computer-aided detection/diagnosis (CAD), we present a CAST software system for a fully automatic initial interpretation of coronary CT angiography (CCTA). We show how the system design and diagnostic performance make it CAST-compliant and suitable for chest pain patient triage in emergency room (ER).MethodsThe processing performed by the system consists of three major steps: segmentation of coronary artery tree, labeling of major coronary arteries, and detection of significant stenotic lesions (causing >xa050% stenosis). In addition, the system performs an automatic image quality assessment to discards low-quality studies. For multiphase studies, the system automatically chooses the best phase for each coronary artery. Clinical evaluation results were collected in 14 independent trials that included more than 2000 CCTA studies. Automatic diagnosis results were compared with human interpretation of the CCTA and to cath lab results.ResultsThe presented system performs a fully automatic initial interpretation of CCTA without any human interaction and detects studies with significant coronary artery disease. The system demonstrated higher than 90% per patient sensitivity and 40–70% per patient specificity. For the chest pain, ER population, the specificity was 60–70%, yielding higher than 98% NPV.ConclusionsThe diagnostic performance of the presented CCTA CAD system meets the CAST requirements, thus enabling efficient, 24/7 utilization of CCTA for chest pain patient triage in ER. This is the first fully operational, clinically validated, CAST-compliant CAD system for a fully automatic analysis of CCTA and detection of significant stenosis.

Misplaced parotid glands: bilateral agenesis of parotid glands associated with bilateral accessory parotid tissue

Agenesis of the parotid is a rare entity. It is usually unilateral but bilateral cases have been described as a rare cause of xerostomia. Accessory parotid tissue is also uncommon and is not normally associated with aplasia of the parotid gland. The embryological, histological, clinical and radiological findings of these two entities will be discussed in addition to the report of an obscure case of bilateral parotid agenesis together with bilateral accessory parotid tissue.

Value of multidetector computed tomography evaluation of myocardial perfusion in the assessment of ischemic heart disease: comparison with nuclear perfusion imaging

MDCT-derived myocardial perfusion has not yet been validated against accepted standards. We developed a technique for quantification of myocardial perfusion from MDCT images and studied its diagnostic value against SPECT myocardial perfusion imaging (MPI). Ninety-eight patients were studied. Abnormal perfusion was detected by comparing normalized segmental x-ray attenuation against values obtained in 20 control subjects. Disagreement with resting MPI was investigated in relationship to MDCT image quality, severity of MPI abnormalities, and stress MPI findings. Resting MPI detected mild or worse abnormalities in 20/78 patients. MDCT detected abnormalities in 15/20 patients (sensitivity of 0.75). Most abnormalities missed by MDCT analysis were graded as mild on MPI. Additional abnormalities found in 16/78 patients were not confirmed on resting MPI (specificity of 0.72). However, 8 of these 16 apparently false positive MDCT perfusion tests had abnormal stress MPI; of these 8 patients, 7 had optimal MDCT image quality, while in 6/8 remaining patients, image quality was suboptimal. When compared with resting MPI, MDCT detected perfusion abnormalities with high accuracy. Moreover, half of MDCT perfusion abnormalities not confirmed by resting MPI were associated with abnormal stress MPI. Importantly, this information can be obtained without additional radiation dose or contrast agent.

Sacroiliac joint bridging: demographical and anatomical aspects.

Study Design. A descriptive study of the association between sacroiliac joint bridging (SIB) and age, gender, laterality, and ethnic origin in a normal skeletal population. The effectiveness of radiographs in identifying SIB was also evaluated. Objectives. To characterize the phenomenon of SIB demographically and anatomically and to evaluate the validity of diagnosis based on roentgenograms. Summary and Background Data. Although SIB is an important diagnostic parameter in many spinal diseases, the type of association between them has never been established. Furthermore, the extent of SIB in humans and its relationship to demographic parameters await osteological research as radiograph studies hamper the results. Methods. Two thousand eight hundred and forty-five skeleton pelves were examined for SIB. Extent and laterality were recorded. Ten pelves (5 with SIB and 5 without) were X-rayed and the roentgenograms given to radiologists for evaluation. Results. Sacroiliac bridging was present in 12.27% of all males, contrasted with only 1.83% of females (P < 0.001). SIB was independent of ethnic origin (P = 0.0535) but was age-dependent (r = 0.985; P = 0.0001). Bridging was present bilaterally in 38.6% of the individuals and in the superior region in 72.4%. Diffuse bridging (areas 1–6) was present in only 2.3% of the individuals. Radiologic examination was insensitive to diagnosis of SIB. Conclusions. SIB is a common, but predominantly male phenomenon. Its occurrence is age-dependent and ethnicity independent. Bridging occurs mainly on the superior aspect of the sacroiliac joint. The irregular shape and orientation of sacroiliac joints preclude definitely distinguishing normal versus bridged joints from roentgenograms. Our findings also negate the belief that bridging/fusion of the sacroiliac joint represents the most severe form of osteoarthritis and mandate that they be separately recorded and that their significance be determined.

Visceral abdominal adipose tissue and coronary atherosclerosis in asymptomatic diabetics

BACKGROUNDnVisceral abdominal adipose tissue (VAT) may play an active role in the progression of coronary atherosclerosis. We examined the relation between VAT, non-alcoholic fatty liver disease and extent of coronary atheroma in patients with type 2 diabetes mellitus but no known coronary artery disease.nnnMETHODSnCoronary artery calcium and area, distribution and thickness of upper abdominal fat were measured in selected axial cross-sections from non-enhanced computed tomography (CT) scans of the chest. Coronary atheroma was assessed visually on a per vessel basis from 64 slice CT angiography using axial views and multi-format reconstructions. Fatty liver was diagnosed when liver density was <40 Hounsfield units (HU) or ≥10 HU below spleen density.nnnRESULTSnThe area of VAT was increased in patients with versus without multi-vessel coronary artery plaque (237.0 ± 101.4 vs 179.2 ± 79.4 mm(2), p<0.001). Waist circumference (101.6 ± 12.3 versus 95.3 ± 13.8 cm) and internal abdominal diameter (218.7 ± 33.0 vs 194.6 ± 25.7 mm) (both p<0.001) were increased in patients with multi-vessel plaque whereas subcutaneous fat was unrelated to coronary plaque. Presence of fatty liver (93/318 patients, 29.2%) did not correlate with presence or extent of coronary plaque. The correlation of VAT with multi-vessel plaque although nominally independent of the metabolic syndrome (p=0.04) was not independent of waist circumference.nnnCONCLUSIONnIn asymptomatic subjects with DM and no history of CAD area of VAT correlated with the presence and extent of coronary atheroma but as a risk predictor added little independent information to that obtained by more readily obtainable measures of adiposity-waist circumference and internal abdominal diameter.

Uses and Limitations of 40 Slice Multi-Detector Row Spiral Computed Tomography for Diagnosing Coronary Lesions in Unselected Patients Referred for Routine Invasive Coronary Angiography

Background and Aims: The value of multi-detector row computed tomography (MDCT) in routine cardiology practice is uncertain. We examined the applicability of MDCT imaging for the diagnosis of obstructive coronary artery disease in a routine clinical setting. Methods: MDCT scanning (40 slice) was performed in 111 unselected patients referred for invasive coronary angiography (ICA) and findings were compared to an independent quantitative assessment of the ICA on a segmental, vessel and patient basis. Results: Sensitivity and positive predictive value for segmental disease (72.2 and 70.9% respectively, overall) were higher in patients aged ≧60 years and history of disease ≧1 year, whereas specificity and negative predictive value were high in all groups. In the patient-based analysis, sensitivity and positive predictive value (84.7 and 87.8%, respectively) were higher, the latter in keeping with the high-patient prevalence of disease, but specificity and negative predictive value (61.5 and 55.2%) were low. Conclusions: Usefulness of MDCT was significantly influenced by age, duration of coronary artery disease and female gender, and on a patient-based analysis its diagnostic accuracy was not sufficient to replace ICA in a routine clinical setting.