Felipe S. Torres

Role of MDCT coronary angiography in the evaluation of septal vs interarterial course of anomalous left coronary arteries

BACKGROUND Conventional coronary angiography (CCA) may be inaccurate to distinguish between interarterial and septal subtypes of anomalous left coronary arteries (CAs). OBJECTIVE We compared the classification of anomalous left CA arising from the right sinus of Valsalva (RSV) or right CA on the basis of multidetector computed tomography coronary angiography (MDCTCA) with the classification derived from CCA. METHODS A retrospective review of 6000 consecutive electrocardiographic-gated MDCTCAs identified 15 cases of anomalous left main or left anterior descending CA arising from the RSV or right CA coursing between the aorta and the main pulmonary artery. On the basis of MDCTCA findings, the proximal course of each vessel was classified into 3 subtypes: 1, interarterial; 2, septal; and 3, mixed. CCA was reviewed in 5 cases (33%) and classified according to traditional criteria. When CCA images were not available, 3-dimensional volume-rendered reconstructions were used to simulate CCA. RESULTS On the basis of MDCTCA, subtypes were distributed as type 1 (n = 2), type 2 (n = 4), and type 3 (n = 8). One case could not be classified into any of these subtypes and was classified as type 4, right ventricular infundibulum (RVI). Applying CCA criteria, 2 cases would have been classified as interarterial and 14 as septal without appreciation of the mixed or RVI subtypes. CONCLUSIONS Classification of anomalous left CAs into either septal or interarterial may be too simplistic. There is an anatomic spectrum of anomalous left CAs detected by MDCTCA that challenges the traditional classification based on CCA.

Abolition of Respiratory-Motion Artifact in Computed Tomography Coronary Angiography with Ultrafast Examinations: A Comparison Between 64-row and 320-row Multidetector Scanners

Purpose To compare the incidence of respiratory artifact in computed tomography (CT) coronary angiography performed with 64-row and 320-row multidetector scanners and to assess its effect on coronary evaluability. Methods A retrospective review of consecutive coronary angiograms performed on a 64-row multidetector CT from March to April 2007 (group 1: 115 patients, 63 men; mean age [standard deviation] 59.6 ± 12.8 years) and on a 320-row multidetector CT from March to April 2008 (group 2: 169 patients, 89 men; mean [SD] age 57.9 ± 11.6 years). Two cardiac radiologists assessed the occurrence of respiratory artifact and coronary evaluability in studies with respiratory artifacts. Unevaluable coronary segments because of motion at the same anatomical level of the respiratory artifact were considered unevaluable because of this artifact. The association between the occurrence of respiratory artifact and patient biometrics, medication, and scan parameters was examined. Results Respiratory artifacts were detected in 9 of the 115 patients from group 1 (7.8%) and in none of the 169 patients from group 2 (P < .001). Group 1 had longer scan times (median, 9.3 seconds; range, 7.5−14.4 seconds) compared with group 2 (median, 1.5 seconds; range, 1.1−3.5 seconds; P < .001). In group 1, 4 patients (3.5%) showed unevaluable coronary segments because of respiratory artifacts, and the CT coronary angiography was repeated in 1 patient (0.9%). Conclusions Respiratory artifacts are important in CT coronary angiography performed with 64-row multidetector scanners and impair the diagnostic utility of the examination in up to 3.5% of the studies. These artifacts can be virtually eliminated with a faster scan time provided by 320-row multidetector CT.

The value of stress perfusion cardiovascular magnetic resonance imaging for patients referred from the adult congenital heart disease clinic: 5-year experience at the Toronto General Hospital

BACKGROUND Vasodilator stress perfusion cardiovascular magnetic resonance imaging is a clinically useful tool for detection of clinically significant myocardial ischaemia in adults. We report our 5-year retrospective experience with perfusion cardiovascular magnetic resonance in a large, quarternary adult congenital heart disease centre. METHODS We reviewed all cases of perfusion cardiovascular magnetic resonance in patients referred from the adult congenital heart disease service. Dipyridamole stress perfusion cardiovascular magnetic resonance was undertaken on commercially available 1.5 and 3 T cardiovascular magnetic resonance scanners. Late gadolinium enhancement imaging was performed 8-10 minutes after completion of the rest perfusion sequence. Navigator whole-heart coronary magnetic resonance angiography was also performed where feasible. RESULTS of stress cardiovascular magnetic resonance were correlated with complementary imaging studies, surgery, and clinical outcomes. RESULTS Over 5 years, we performed 34 stress perfusion cardiovascular magnetic resonance examinations (11 positive). In all, 84% of patients had further investigations for ischaemia in addition to cardiovascular magnetic resonance. Within a subgroup of 19 patients who had definitive alternative assessment of their coronary arteries, stress perfusion cardiovascular magnetic resonance demonstrated a sensitivity of 82% and specificity of 100%. Of the 34 studies, two were false negatives, in which the aetiology of ischaemia was extrinsic arterial compression rather than intrinsic coronary luminal narrowing. Coronary abnormalities were identified in 71% of cases who had coronary magnetic resonance angiography. CONCLUSION Stress perfusion cardiovascular magnetic resonance is a useful and accurate tool for investigation of myocardial ischaemia in an adult congenital heart disease population with suspected non-atherosclerotic coronary abnormalities.

Strategies for Radiation-dose Reduction and Image-quality Optimization in Multidetector Computed Tomographic Coronary Angiography

The technological evolution of computed tomography (CT) in the last decade has placed CT coronary angiography (CTCA) in the spotlight of imaging modalities available to evaluate patients with coronary artery disease. Widespread utilisation of CTCA has generated concern from the medical community regarding potential health issues related to the significant radiation exposure associated with this method, and several modifications of the CTCA technique have been proposed to reduce the radiation exposure without affecting the diagnostic image quality. This review will discuss a practical approach to performing CTCA to ensure that the radiation dose is minimized while maintaining diagnostic image quality.

Coronary Calcium Scan Acquisition Before Coronary CT Angiography: Limited Benefit or Useful Addition?

OBJECTIVE This article reviews the role of coronary calcium quantification in symptomatic patients and the pros and cons of acquiring an unenhanced coronary calcium scan in every patient with suspected coronary artery disease referred for coronary CT angiography. CONCLUSION The acquisition of a coronary calcium scan in every symptomatic patient referred for coronary CT angiography requires a case-by-case approach.

β-Blockers to Control Heart Rate during Coronary CT Angiography

We are grateful for the opportunity offered by Dr Darge in his letter to acknowledge the important nonvascular applications of microbubble contrast agents for US. While our review focused on the role of these agents in providing intravascular contrast for diagnosis ( 1 ), Dr Darge describes CE voiding urosonography, one of several established nonvascular applications of microbubbles. These include hysterosalpingo– contrast sonography ( 2 ), which is reported to be as accurate as hysterosalpingography in determining fallopian tube patency ( 3 ), and sentinel node US with intradermal injections of microbubbles, which has been validated in animal models ( 4 ) and recently demonstrated successfully in patients with breast cancer ( 5 ).

Extracardiac Findings in Cardiac CT

AJR 2014; 202:W411 0361–803X/14/2024–W411

Aneurysm and dissection in a patient with syphilitic aortitis

In the antibiotic era, aortic aneurysm is a rare complication of syphilis, what makes the diagnostic assumption even more difficult. Nonetheless, this condition should be suspected in patients with aortic aneurysm. Reports of aortic dissection complicating syphilitic aortitis have been distinctly rare in the literature, and their cause-effect relationship has not been definitely established. In this case report, we present a 62-year-old woman with aortic aneurysm and dissection associated with an unexpected diagnosis of syphilitic aortitis.

Cardiac MR imaging for the evaluation of autoimmune myocarditis

I read with great interest the article from Toong and colleagues regarding the use of cardiac magnetic resonance (MR) imaging to evaluate the presence of myocarditis in 3 cases with autoimmune myositis (1). In case number 2, cardiac MR imaging was performed and showed ‘‘patchy mid-wall late gadolinium enhancement in the basal aspect of the lateral and septal walls of the left ventricle, consistent with localized myocarditis’’. However, Fig. 2 demonstrates a static frame of a balanced-steady state free precession image (b-SSFP) of a 2-chamber view and, in contrary to the figure description, it does not reveal localized myocarditis and does not show the septal or lateral walls, where, according to the authors, there were abnormalities on late gadolinium enhancement (LGE) acquisitions. Cardiac MR imaging has an established value in the evaluation of suspected myocarditis, particularly in patients with elevated troponins and normal coronary arteries (2). Myocardial edema and hyperemia, as assessed by T2weighted images and early myocardial gadolinium enhancement, respectively, and, in more severe cases, irreversible myocardial damage, as assessed by LGE, have demonstrated its usefulness in the diagnosis of myocarditis (3). Cine b-SSFP sequences, the working horse of cardiac MR imaging, can demonstrate global or regional wall motion abnormality (WMA) but, in isolation, cannot demonstrate localized myocarditis, since regional WMA has a low specificity for the underlying pathophysiology. All these sequences, in conjunction, are indicated for the evaluation of patients with myocarditis (3). It would have been more useful if the authors had shown the abnormal MR images of the reported cases (cases 2 and 3), particularly the LGE images, since, as the authors point out, cardiac MR imaging with the use of gadolinium in cases of autoimmune myocarditis is still limited to small case series.

Low diagnostic yield of Late Gadolinium Enhancement (LGE) in screening patients with suspected Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) by Cardiovascular Magnetic Resonance (CMR)

Background ARVC is a rare potentially life-threatening inherited disease of the desmosome. Right ventricular wall motion abnormalities combined with right ventricular dilatation or impaired function on CMR are diagnostic criteria for this disease. The role of LGE in this disease is still under debate. This study was performed to investigate the yield of LGE by CMR in patients referred with suspected ARVC. Methods