An Updated Comparison of Conventional Coronary Angiography With Cardiac Magnetic Resonance Imaging to Diagnose the Origin and Proximal Course of Anomalous Coronary Arteries.

BACKGROUND: Anomalous coronary arteries (ACAs) may present increased risk for adverse cardiac events. We sought to evaluate the accuracy of conventional coronary angiography (CCA), as it is currently used in clinical practice, compared with expert interpretation and cardiac magnetic resonance imaging (CMR) in determining the site of origin and proximal course of ACAs. METHODS: Fifty consecutive patients without concomitant congenital heart disease, who were referred for CMR to diagnose the course of an ACA, were retrospectively evaluated. Original CCA reports were reviewed. Angiography images were available in all patients and were interpreted by 2 experts blinded to the prior interpretation and CMR results. The accuracy of interpretation in each group was then compared to the current gold standard of CMR. RESULTS: Identification of the site of origin (ie, aortic sinus) by referring angiographers was similar to that of expert angiographers (sensitivity, 89% vs 98%, respectively; P=.10). However, referring angiographers were less likely to correctly identify the proximal course as compared with expert angiographers (sensitivity, 27% vs 98%, respectively; P<.001). CONCLUSIONS: As it is used in current practice, CCA does not provide sufficient diagnostic accuracy for identifying the proximal course of an ACA. Review by expert angiographers added sensitivity, improving the accuracy to nearly 100%. Expert consultation may be nearly as accurate as advanced imaging, and should be considered in cases of ACA in which there is diagnostic uncertainty.

Cardiac transplant patients response to the (31)P MRS stress test.

BACKGROUND: Previous studies showed low resting phosphocreatine/adenosine triphosphate (PCr/ATP) ratios within this patient population compared with controls; however, these low PCr/ATP did not correlate with endomyocardial biopsy rejection. One possible explanation is the presence of cardiac allograft vasculopathy (CAV), which might be manifested as a transient ischemic event in the mildly stressed transplanted heart. If transient ischemia is invoked through the (31)P magnetic resonance spectroscopy (MRS) stress test, monitoring of such an event should be achievable and thus implicating possible ischemic involvement. METHODS: Heart transplant patients (n = 25) and normal controls (n = 11) were studied using the (31)P MRS stress test; 10 patients tested positive (> 2 standard deviations [SDs] from control values). Patients also were monitored for heart rate and blood pressure with the handgrip exercise generating a small increase in the rate-pressure product. RESULTS: The percent change (%Delta) in the PCr/ATP ratio in the control group was 1.50% +/- 10.6; the transplant population showed an overall change of -6.7% +/- 18.5. The responders, those that were at or below the 2 SD line from control, had a -25.6 +/- 3.6% Delta PCr/ATP; whereas the non-responders reflect a 5.1 +/- 13.4%. The responders' response is quite striking when considering the threshold for an abnormal PCr/ATP %Delta in response to stress testing was -19.7%, which was the 2 SD mark below the mean value for the reference population. DISCUSSION: The (31)P MRS stress test showed that a possible transient ischemic event occurred in a subset of patients, thus implicating possible CAV in the cardiac transplant patient. Such an approach may provide an early diagnosis of this disease.

X-ray angiography and magnetic resonance imaging to distinguish interarterial from septal courses of anomalous left coronary artery: an ex vivo heart model.

OBJECTIVE: We sought to demonstrate the distinguishing features between interarterial and intraseptal courses of an anomalous left coronary artery from the right sinus of Valsalva (RSV) on X-ray angiography, using an ex vivo model. BACKGROUND: An anomalous left main coronary artery (LMCA) arising from the RSV can take prepulmonary, retro-aortic, interarterial (IA) or intraseptal (IS) courses, of which only the IA course is associated with sudden death. Anomalous LMCA is usually identified during catheter angiography. On Xray angiography, IA and IS courses have common characteristics that makes their distinction challenging. We hypothesized that the cranialcaudal orientation of the vessel on X-ray angiography allows these pathways to be distinguished, and tested this hypothesis using an ex vivo heart model. METHODS: Plastic tubing was inserted along the IA and IS courses in an ex vivo normal pig heart. X-ray imaging in standard views and MRI on a 3-T scanner were performed. RESULTS: In a normally formed heart, an anomalous LMCA with IA path must take a cephalad course, superior to the pulmonary valve. Conversely, an IS vessel will pass caudally, at or below the level of the infundibular septum. These findings were demonstrated in the X-ray angiograms and confirmed by magnetic resonance imaging. CONCLUSIONS: X-ray angiography can differentiate IA and IS courses of an anomalous LMCA in the normally formed heart. This may obviate the need for further cross-sectional imaging in many cases.

Executive function is associated with brain proton magnetic resonance spectroscopy in amnestic mild cognitive impairment.

Persons with amnestic mild cognitive impairment (MCI) show deficits on executive function measures, although the neuroanatomic basis of executive function in MCI is unknown. We investigated cognitive correlates of 3-tesla proton magnetic resonance spectroscopy (MRS) of the posterior cingulate gyrus in 26 MCI patients. Posterior cingulate ratio of myo-inositol to creatine (mI/Cr) was negatively correlated (-.51) with spontaneous clock drawing. This relationship was not attenuated after accounting for age, overall cognitive function, or memory performance. This finding suggests a role for the posterior cingulate in executive function in MCI. Proton MRS may offer a means to track neurometabolic changes associated with cognitive impairment in MCI.

Elevated brain scyllo-inositol concentrations in patients with Alzheimer's disease.

in vivo (1)H MRS reveals reduced N-acetylaspartate (NAA) and elevated myo-inositol (mI) in patients with mild Alzheimer's disease (AD) and patients with amnestic mild cognitive impairment (MCI). We are unaware of studies that have documented abnormal scyllo-inositol (sI) levels in patients with AD or patients with MCI, although a previous MRS study in older adults has indicated that sI is a peak of interest to measure in AD. Fifteen patients with mild AD, 26 patients with amnestic MCI, and 19 healthy older adults were recruited to this study. All underwent (1)H MRS of the posterior cingulate gyrus of the brain using a 3 T MRI scanner. Increases in the sI/creatine (Cr) ratio were observed in patients with mild AD (P < 0.05). The mI/Cr ratio was raised in patients with mild AD (P < 0.01) and MCI (P < 0.05). Reduced NAA/Cr was detected in patients with mild AD (P < 0.05). The sI/Cr ratio correlated negatively (r = -0.60, P < 0.05) with a measure of clock drawing in patients with mild AD, indicating that impaired cognitive ability in AD is associated with higher concentrations of sI/Cr. In vivo measurement of sI/Cr in the posterior cingulate gyrus of patients with mild AD revealed increases compared with cognitively healthy older adults. Further research on the mechanisms of sI increase in AD is needed. Future studies on the longitudinal course of sI/Cr in MCI and AD appear warranted.

PCr overshoot': a study of the duration in canine myocardium.

The phosphocreatine (PCr) overshoot is a well-documented phenomenon and is readily observable by 31P MRS. In addition, a second 31P MRS observation during ischemia with reperfusion is a diminution in ATP levels. Combining these two as the 'PCr Overshoot' the PCr/ATP ratio may provide an index of viability. However little information is available regarding the duration of this 'overshoot'. For this approach to be useful clinically, the duration of this phenomenon must be ascertained. An open chest canine model of 12 min of ischemia followed by reperfusion (6h) was used. A 2 cm surface coil was sutured to the myocardium and spectra were acquired at 4.7 T. Gated spectra were acquired in <2.5 min with an interpulse delay of 5 s. Integrals of the PCr and ATP (beta) resonances were analyzed using a line-fitting routine. Overall, the PCr signal increased from 22.0+/-0.8 to 25.5+/-0.9 and ATP decreased from 11.7+/-0.4 to 10.0+/-0.4 (arbitrary units). The PCr remained elevated for the entire 6h period and the percentage increase was 15.9%. The ATP remained depleted for the entire 6h period and the percentage decrease was 17.0%. Thus, the clinically relevant and readily observable PCr/ATP is a product of both an increase in PCr and a decrease in ATP for a calculated net increase in PCr/ATP of 39.6%. The PCr/ATP ratio of the ischemia group for baseline, ischemia, 6h reflow, were: 2.33+/-0.18, 1.04+/-0.29 and 3.22+/-0.21. We demonstrate that the 'PCr overshoot' is readily observable and can be monitored noninvasively and nondestructively for 6h. Therefore, the 'PCr overshoot' may be a viable marker of reversible injury in this model and may prove to be applicable for detecting myocardial viability in patients.