Detection of myocardial bridging by 64-row computed tomography angiography of the coronaries

INTRODUCTION: Myocardial bridging is a congenital condition in which a section of coronary artery is surrounded by myocardium. Historically, myocardial bridging has been diagnosed by catheter angiography. This study investigates the effectiveness of electrocardiogram-gated 64-slice multidetector computed tomography in detecting myocardial bridging. MATERIALS AND METHODS: We retrospectively reviewed 167 consecutive patients referred for coronary computed tomography angiography between January 4, 2005, and May 24, 2006. We recorded the number of coronary segments exhibiting myocardial bridging and described the location of each according to the American Heart Association classification system. Association of bridging with factors influencing image quality (body mass index and heart rate) was analyzed. RESULTS: Of 152 eligible participants, 49 (32%) showed myocardial bridging. The mid-left anterior descending coronary artery (segment 7) was the most common location accounting for 69% of positive cases. Body mass index and heart rate did not affect detection rates. CONCLUSION: Electrocardiogram-gated 64-slice multidetector computed tomography is a feasible, noninvasive method of detecting myocardial bridging which may offer higher sensitivity than catheter angiography for this diagnosis.     

Quantification of myocardial ischemia and infarction with single photon emission computed tomography

To evaluate the feasibility of ²⁰¹Tl single photon emission computed tomography (SPECT) for quantitative detection of myocardial infarction and ischemia, scintigraphic studies were related to angiographic findings. In study A infarct sizes with SPECT were compared with the angiographic infarct sizes of 30 patients. A linear correlation was found for the % infarct of the left ventricular circumference between both methods (r=0.73; P< 0.001; mean infarct size 20.7%±10.5% (angio) vs 19.8%±12.9% (SPECT), mean±SD). Furthermore, a significant inverse correlation between scintigraphic infarct size and left ventricular ejection fraction (r=-0.87, P< 0.001) was obtained. In study B exercise/rest ²⁰¹Tl SPECT was used for quantification of myocardial ischemia. Forty-three patients underwent both stress ²⁰¹Tl SPECT and biplane exercise left ventriculography. Ischemia was expressed as % defect size of the left ventricular circumference. Sensitivity and specificity for detection of ischemia were 96% and 100% respectively with stress SPECT. Extent of myocardial ischemia correlated significantly with both methods (r=0.63; SPECT defect=1.0 angiographic ischemia +2%; P< 0.001). The regression followed the line of identity and the mean sizes of ischemia were identical (SPECT 12.2±7.6% vs 14.6±12.4% ventriculography, mean±SD) demonstrating the agreement of both methods. However, there was some intraindividual variance between the scintigraphic and the angiographic study. The sensitivity and specificity in single regions with SPECT were lower compared to the global test results. The correlation between the non invasive SPECT and the ventriculography in detection of myocardial infarction and ischemia indicates the clinical value of ²⁰¹Tl SPECT for diagnosis of coronary heart disease.Parts of the results were presented at the 58th sessions of the American Heart Association at Washington, DC (1985)     

Quantification of myocardial ischemia and infarction with single photon emission computed tomography

To evaluate the feasibility of 201Tl single photon emission computed tomography (SPECT) for quantitative detection of myocardial infarction and ischemia, scintigraphic studies were related to angiographic findings. In study A infarct sizes with SPECT were compared with the angiographic infarct sizes of 30 patients. A linear correlation was found for the % infarct of the left ventricular circumference between both methods (r = 0.73; P less than 0.001; mean infarct size 20.7% +/- 10.5% (angio) vs 19.8% +/- 12.9% (SPECT), mean +/- SD). Furthermore, a significant inverse correlation between scintigraphic infarct size and left ventricular ejection fraction (r = -0.87, P less than 0.001) was obtained. In study B exercise/rest 201Tl SPECT was used for quantification of myocardial ischemia. Forty-three patients underwent both stress 201Tl SPECT and biplane exercise left ventriculography. Ischemia was expressed as % defect size of the left ventricular circumference. Sensitivity and specificity for detection of ischemia were 96% and 100% respectively with stress SPECT. Extent of myocardial ischemia correlated significantly with both methods (r = 0.63; SPECT defect = 1.0 angiographic ischemia +2%; P less than 0.001). The regression followed the line of identity and the mean sizes of ischemia were identical (SPECT 12.2 +/- 7.6% vs 14.6 +/- 12.4% ventriculography, mean +/- SD) demonstrating the agreement of both methods. However, there was some intraindividual variance between the scintigraphic and the angiographic study. The sensitivity and specificity in single regions with SPECT were lower compared to the global test results.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of computed tomography in vertebrobasilar ischemia

Summary Precise delineation of vertebrobasilar ischemia by computed tomography (CT) appears difficult due to the numerous variations in distribution of the posterior fossa arterial supply. While pontine and upper brainstem infarctions can be readily demonstrated, medullary infarction remains beyond the scope of present CT scanners. CT findings in cases of basilar artery occlusion include bilateral pontine infarction or extensive brainstem ischemia, associated with cerebellar and posterior cerebral vascular damage. Demonstration of basilar artery occlusion using routine CT is only rarely achieved. In cerebellar ischemia, CT, in conjunction with clinical syndromes, helps in the recognition of the arterial territory involved. CT provides useful guidelines for the treatment of cerebellar stroke, leading to surgery in cases of massive cerebellar infarction.     

Differentiation of myocardial ischemia and infarction assessed by dynamic computed tomography perfusion imaging and comparison with cardiac magnetic resonance and single-photon emission computed tomography

Objectives

To evaluate the feasibility of myocardial blood flow (MBF) by computed tomography from dynamic CT perfusion (CTP) for detecting myocardial ischemia and infarction assessed by cardiac magnetic resonance (CMR) or single-photon emission computed tomography (SPECT).

Methods

Fifty-three patients who underwent stress dynamic CTP and either SPECT (n?=?25) or CMR (n?=?28) were retrospectively selected. Normal and abnormal perfused myocardium (ischemia/infarction) were assessed by SPECT/CMR using 16-segment model. Sensitivity and specificity of CT-MBF (mL/g/min) for detecting the ischemic/infarction and severe infarction were assessed.

Results

The abnormal perfused myocardium and severe infarction were seen in SPECT (n?=?90 and n?=?19 of 400 segments) and CMR (n?=?223 and n?=?36 of 448 segments). For detecting the abnormal perfused myocardium, sensitivity and specificity were 80 % (95 %CI, 71-90) and 86 % (95 %CI, 76-91) in SPECT (cut-off MBF, 1.23), and 82 % (95 %CI, 76-88) and 87 % (95 %CI, 80-92) in CMR (cut-off MBF, 1.25). For detecting severe infarction, sensitivity and specificity were 95 % (95 %CI, 52-100) and 72 % (95 %CI, 53-91) in SPECT (cut-off MBF, 0.92), and 78 % (95 %CI, 67-97) and 80 % (95 %CI, 58-86) in CMR (cut-off MBF, 0.98), respectively.

Conclusions

Dynamic CTP has a potential to detect abnormal perfused myocardium and severe infarction assessed by SPECT/CMR using comparable cut-off MBF.

Key Points

? CT-MBF accurately reflects the severity of myocardial perfusion abnormality. ? CT-MBF provides good diagnostic accuracy for detecting myocardial perfusion abnormalities. ? CT-MBF may assist in stratifying severe myocardial infarction in abnormal perfusion myocardium.

     

Detection of basilar artery thrombosis by computed tomography

Thrombosis of the basilar artery is not uncommon and occurs in the elderly as well as in younger patients. The clinical diagnosis may be supported by the appearance on computed tomography enabling appropriate investigations and therapeutic measures to be taken which may lead to a favourable outcome. Four cases of basilar artery thrombosis are described in which the clinical diagnosis was assisted by computed tomography. The basilar artery, which is normally isodense in unenhanced studies, was seen as a hyperdense structure. Follow-up scans demonstrated a decrease in the density and size of the vessel consistent with resolution of a thrombus.     

Detection of pulmonary nodules by computed tomography.

In 11 of 23 patients, computed tomography of the chest detected pulmonary nodules that were not detected by conventional chest radiography or whole lung tomography. CT is recommended for patients suspected of having pulmonary metastasis and those with a solitary pulmonary nodule.     

Detection of retroperitoneal hemorrhage by computed tomography.

Retroperitoneal hemorrhage can be directly documented by computed tomography. In patients with confusing clinical findings, CT scans may provide a definite diagnoses and direct appropriate therapy. This contention is supported by seven illustrative cases.     

Detection of subcutaneous metastases by computed tomography.

Subcutaneous fat provides excellent contrast for water density tissue. Five patients with subcutaneous metastases visualized on computed tomography (CT) scans are presented. In some cases, CT proved to be the optimal diagnostic modality for visualizing these lesions and documenting their response to therapy.     

Detection of myocardial bridge and evaluation of its anatomical properties by coronary multislice spiral computed tomography

BACKGROUND: Myocardial bridge (MB) is a common anatomical condition, under which a part of the coronary artery running in the epicardial adipose tissue, is covered with myocardial tissue. It regulates atherosclerosis development and sometimes evokes coronary heart disease through haemodynamic alterations. We attempted to efficiently detect MB and evaluate the anatomical properties of MB by coronary multislice spiral computed tomography (MSCT). METHODS: Sixteen-row MSCT was conducted on 148 patients with coronary heart disease. MSCT images were reconstructed and reformed with transverse scans, curved planar reformat and three-dimensional volume-rendered images. The MB, over 1.0 mm in thickness, was identified by the presence of the "step-down and step-up" appearance. After "trial and error" essays, we could consistently examine the frequency of MB and evaluate the anatomical properties of MB, especially its thickness, together with coronary wall lesions. RESULTS: Twenty-three patients (15.8%) had MB over 1.0 mm in thickness: 21 MBs (87.5%) were located in the left anterior descending artery with a mean thickness and length of 1.8+/-0.7 and 20.0+/-8.6 mm. Moreover, although the tunneled segment beneath MB was always free of coronary wall lesions, 79.2% (19/24) of the segments proximal to MB demonstrated coronary wall lesions. Of special significance were three symptomatic MB patients without any atherosclerotic lesion throughout all the coronary arteries. CONCLUSION: Coronary MSCT is a new imaging technique that provides a non-invasive diagnostic tool for MB and yields much better results of MB detection than previous imaging methods.     

Epicardial adipose tissue and myocardial ischemia assessed by computed tomography perfusion imaging and invasive fractional flow reserve

Background

Epicardial adipose tissue (EAT) is a metabolically active fat depot that is associated with incident coronary artery disease (CAD) and major adverse cardiovascular events. The relationship between EAT and myocardial ischemia remains unclear. This study investigated the relationship between EAT volume and the presence of perfusion defects on myocardial computed tomographic perfusion imaging (CTP) and functional stenoses on invasive fractional flow-reserve (FFR).

Detection of mild emphysema by computed tomography density measurements

Purpose: To assess the ability of a conventional density mask method to detect mild emphysema by high-resolution computed tomography (HRCT); to analyze factors influencing quantification of mild emphysema; and to validate a new algorithm for detection of mild emphysema.

Material and Methods: Fifty-five healthy male smokers and 34 never-smokers, 61-62 years of age, were examined. Emphysema was evaluated visually, by the conventional density mask method, and by a new algorithm compensating for the effects of gravity and artifacts due to motion and the reconstruction algorithm. Effects of the reconstruction algorithm, slice thickness, and various threshold levels on the outcome of the density mask area were evaluated.

Results: Forty-nine percent of the smokers had mild emphysema. The density mask area was higher the thinner the slice irrespective of the reconstruction algorithm and threshold level. The sharp algorithm resulted in increased density mask area. The new reconstruction algorithm could discriminate between smokers with and those without mild emphysema, whereas the density mask method could not. The diagnostic ability of the new algorithm was dependent on lung level. At about 90% specificity, sensitivity was 65-100% in the apical levels, but low in the rest of the lung.

Conclusion: The conventional density mask method is inadequate for detecting mild emphysema, while the new algorithm improves the diagnostic ability but is nevertheless still imperfect.     

双源双能量CT心肌灌注成像的研究进展

近年来,双源双能量CT心肌灌注成像在临床中的应用及研究逐渐增多,能够反映心肌微循环状况,定性及定量地评价心肌血流状态,检测心肌微循环及心肌活性,并且可以在评估冠状动脉的同时评估由于心肌缺血导致的心肌受损情况。其诊断心肌损伤的灵敏度、特异度、阴性预测值和阳性预测值与组织病理学检查的一致性好。相对于其他检查技术,双能量心肌灌注成像能便捷地提供更丰富的临床信息。笔者对双源双能量CT心肌灌注成像的研究进展进行综述。