Comparison of coronary flow reserve estimated by dynamic radionuclide SPECT and multi-detector x-ray CT.

BACKGROUND: Recent technical advances in multi-detector computed tomography (MDCT) allow for assessment of coronary flow reserve (CFR). We compared regional CFR by dynamic SPECT and by dynamic MDCT in patients with suspected or known coronary artery disease (CAD). METHODS: Thirty-five patients, (29 males, mean age 69 years) with greater than average Framingham risk of CAD, underwent dipyridamole vasodilator stress imaging. CFR was estimated using dynamic SPECT and dynamic MDCT imaging in the same patients. Myocardial perfusion findings were correlated with obstructive CAD (≥50% luminal narrowing) on CT coronary angiography (CA). RESULTS: Mean CFR estimated by SPECT and MDCT in 595 myocardial segments was not different (1.51 ± 0.46 vs. 1.50 ± 0.37, p = NS). Correlation of segmental CFR by SPECT and MDCT was fair (r 2 = 0.39, p < 0.001). Bland-Altman analysis revealed that MDCT in comparison to SPECT systematically underestimated CFR in higher CFR ranges. By CTCA, 12 patients had normal CA, 11 had non-obstructive, and 12 had obstructive CAD. CFR by both techniques was significantly higher in territories of normal CA than in territories subtended by non-obstructive or obstructive CAD. SPECT CFR was also significantly different in territories subtended by non-obstructive and obstructive CAD, whereas MDCT CFR was not. CONCLUSION: Despite relative underestimation of high CFR values, MDCT CFR shows promise for assessing the pathophysiological significance of anatomic CAD.

MELAS Syndrome with Cardiac Involvement: A Multimodality Imaging Approach.

A 49-year-old man presented with chest pain, dyspnea, and lactic acidosis. Left ventricular hypertrophy and myocardial fibrosis were detected. The sequencing of mitochondrial genome (mtDNA) revealed the presence of A to G mtDNA point mutation at position 3243 (m.3243A>G) in tRNALeu(UUR) gene. Diagnosis of cardiac involvement in a patient with Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes syndrome (MELAS) was made. Due to increased risk of sudden cardiac death, cardioverter defibrillator was implanted.

Stress Computed Tomography Myocardial Perfusion Imaging: A New Topic in Cardiology.

Since its introduction about 15 years ago, coronary computed tomography angiography has become today the most accurate clinical instrument for noninvasive assessment of coronary atherosclerosis. Important technical developments have led to a continuous stream of new clinical applications together with a significant reduction in radiation dose exposure. Latest generation computed tomography scanners (≥ 64 slices) allow the possibility of performing static or dynamic perfusion imaging during stress by using coronary vasodilator agents (adenosine, dipyridamole, or regadenoson), combining both functional and anatomical information in the same examination. In this article, the emerging role and state-of-the-art of myocardial computed tomography perfusion imaging are reviewed and are illustrated by clinical cases from our experience with a second-generation dual-source 128-slice scanner (Somatom Definition Flash, Siemens; Erlangen, Germany). Technical aspects, data analysis, diagnostic accuracy, radiation dose and future prospects are reviewed.

Transient left ventricular and stomach apical ballooning syndromes: when the trigger is also a clinical emergency.

A 59-year-old woman was referred to our emergency department because of epigastric pain and incoercible vomit. Electrocardiogram showed ST-segment elevation in anterior-lateral leads, but coronary angiogram revealed normal coronary tree and left ventricular angiography showed apical and midventricular akinesis with preserved basal systolic function: a diagnosis of apical ballooning syndrome was made. During the following days, the patient complained about persistent abdominal pain, and a nasogastric tube drained more than 1000 cc of dark fecaloid material. Urgent abdominal computed tomography scan showed a mural thrombus in the apex of the left ventricle and a huge diaphragmatic hernia through which more than one-half of the stomach was herniated and presented a sort of "apical stomach ballooning." Gastropexy was done; surgical diagnosis was a type IV giant diaphragmatic hernia complicated by recent gastric volvulus caused by rotation along the longitudinal cardiopyloric axis. Type IV giant diaphragmatic hernia is relatively rare, representing only about 5% to 7% of all hernias. Gastric volvulus is a severe complication, with acute mortality reported to be as high as 30% to 50%. In our case, a severe life-threatening condition as gastric volvulus triggered an apical ballooning syndrome, a transient cardiomyopathy, usually induced by emotional stressors with a long-term good prognosis. Apical ballooning syndrome must be considered an epiphenomenon of other organic diseases that may have an important role in the prognosis of the patient not only in acute but also in chronic setting. Only early determination of the true cause of apical ballooning syndrome ensures a proper treatment.