Combined use of 64-slice computed tomography angiography and gated myocardial perfusion SPECT for the detection of functionally relevant coronary artery stenoses. First results in a clinical setting concerning patients with stable angina.

AIM: In patients with stable angina pectoris both morphological and functional information about the coronary artery tree should be present before revascularization therapy is performed. High accuracy was shown for spiral computed tomography (MDCT) angiography acquired with a 64-slice CT scanner compared to invasive coronary angiography (ICA) in detecting "obstructive" coronary artery disease (CAD). Gated myocardial SPECT (MPI) is an established method for the noninvasive assessment of functional significance of coronary stenoses. Aim of the study was to evaluate the combination of 64-slice CT angiography plus MPI in comparison to ICA plus MPI in the detection of hemodynamically relevant coronary artery stenoses in a clinical setting. PATIENTS, METHODS: 30 patients (63 +/- 10.8 years, 23 men) with stable angina (21 with suspected, 9 with known CAD) were investigated. MPI, 64-slice CT angiography and ICA were performed, reversible and fixed perfusion defects were allocated to determining lesions separately for MDCT angiography and ICA. The combination of MDCT angiography plus MPI was compared to the results of ICA plus MPI. RESULTS: Sensitivity, specificity, negative and positive predictive value for the combination of MDCT angiography plus MPI was 85%, 97%, 98% and 79%, respectively, on a vessel-based and 93%, 87%, 93% and 88%, respectively, on a patient-based level. 19 coronary arteries with stenoses > or =50% in both ICA and MDCT angiography showed no ischemia in MPI. CONCLUSION: The combination of 64-slice CT angiography and gated myocardial SPECT enabled a comprehensive non-invasive view of the anatomical and functional status of the coronary artery tree.

Pressure-guided nonsurgical myocardial reduction induced by small septal infarctions in hypertrophic obstructive cardiomyopathy.

OBJECTIVES: We sought to assess the safety and efficacy of pressure-guided nonsurgical myocardial reduction (NSMR) with the induction of small septal infarctions in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Nonsurgical myocardial reduction has been shown to decrease left ventricular outflow tract (LVOT) obstruction and to improve symptoms in patients with HOCM. Infarct sizes differ considerably among studies published so far. METHODS: In 50 patients, the LVOT gradient was invasively determined at the time of the intervention, four to six months (n = 49) and 12 to 18 months (n = 25) after NSMR. New York Heart Association functional class and quality of life were assessed by using a standard questionnaire. Exercise capacity was tested by spiro-ergometry. Left ventricular (LV) mass was determined by electron beam computed tomography. RESULTS: Small septal infarctions (mean creatine kinase value 413 +/- 193 U/l) resulted in a sustained decrease in LVOT gradients, from 80 +/- 33 to 18 +/- 17 mm Hg after four to six months (p < 0.001, n = 49) and to 17 +/- 15 mm Hg (p < 0.001, n = 25) after 12 to 18 months. Nonsurgical myocardial reduction was followed by a decrease in LV hypertrophy, which was associated with a sustained increase in exercise capacity, as well as improvement in quality of life. CONCLUSIONS: Pressure-guided NSMR inducing small septal infarctions was sufficient to result in a sustained decrease in LVOT obstruction and to improve symptoms. The incidence of complications, such as complete heart block with necessary permanent pacemaker implantation (<10%), seems to be diminished by minimizing the infarct size.

Correlation of coronary calcification and angiographically documented stenoses in patients with suspected coronary artery disease: results of 1,764 patients.

OBJECTIVES: This study correlated the electron beam computed tomographic (EBCT) calcium scores with the results of coronary angiography in symptomatic patients in order to assess its value to predict or exclude significant coronary artery disease (CAD). BACKGROUND: Electron beam computed tomography is a sensitive method to detect coronary calcium. However, it is unclear whether it may play a role as a filter before invasive procedures in symptomatic patients. METHODS: A total of 1,764 patients (1,225 men and 539 women) with suspected CAD from a single center were included in our study. All patients underwent calcium screening with EBCT (C150XP Imatron) and conventional coronary angiography. RESULTS: Fifty-six percent of men and 47% of women revealed significant coronary stenoses (> or =50%). Total exclusion of coronary calcium (14% of the study group) was associated with an extremely low probability of stenosis (<1%). With calcium scores > or =20th, > or =100th or > or =75th percentile of age groups, the sensitivity to detect stenoses decreased to 97%, 93% and 81%, respectively, in men and to 98%, 82% and 76%, respectively, in women. At the same time, the specificity increased up to 77% in men and women. There was a significant difference in coronary calcium between men and women in all age groups; however, receiver-operating characteristic curves indicated that the test can be performed with equal accuracy in all of these subgroups. CONCLUSIONS: Calcium screening with EBCT is a highly sensitive and moderately specific test to predict stenotic disease. Exclusion of coronary calcium defines a substantial subgroup of patients, albeit symptomatic, with a very low probability of significant stenoses.

Usefulness of calcium scoring using electron beam computed tomography and noninvasive coronary angiography in patients with suspected coronary artery disease.

The aim of this study was to investigate the reliability of calcium scoring (CS) and electron beam computed tomographic angiography (EBCTA) as a noninvasive tool in the diagnosis of coronary artery disease (CAD): 93 consecutive patients (aged 59 +/- 9 years) with symptoms suspicious for CAD underwent CS. In 87 of these subjects, an additional EBCTA investigation was performed. Using receiver-operating characteristic curve analysis, we determined a calcium score cut point providing an overall sensitivity of 80% and a specificity of 72% in detecting patients with CAD. For clinical purposes the use of cut points is difficult. We therefore determined score ranges providing >80% specificity (high score range) and >85% sensitivity (low score range) and determined the scores between these ranges as equivocal borderline scores. Calculated on a per-segment basis in assessable proximal and midcoronary segments, the sensitivity for detecting coronary stenoses >50% was 78%, and the specificity was 93%. Thus, 32 of 44 patients with significant CAD and 24 of 49 patients without CAD were correctly classified. The combination of CS and EBCTA predicted CAD in 77% (72 of 93) of patients. No or low calcium scores provided high specificity for ruling out CAD. The addition of EBCTA in those patients improved sensitivity. In patients with high calcium scores, accuracy of EBCTA was not significantly different from CS alone (72% vs 83%), whereas in patients with borderline scores it was significantly superior (80% vs 58%, p <0.03). Thus, the complementary use of CS and EBCTA appears beneficial, particularly in patients with borderline scores, and could improve sensitivity in the low score range. In the presence of high scores, no major diagnostic gain from an additional EBCTA versus CS alone could be observed.

Accuracy of spiral computed tomography for identifying arterial and venous coronary graft patency.

Late outcome after coronary artery bypass grafting (CABG) mainly depends on the status of graft patency. The recent generation of spiral computed tomography (SCT) scanners may have potential in the long-term follow-up of CABG. In this study, graft patency in patients with internal mammary (IMA) and venous CABG was investigated using SCT and angiography. Forty-nine consecutive patients (age 61 +/- 8 years, 45 men) who had undergone CABG were examined by SCT and angiography 22 +/- 6 months after CABG. In total, 134 bypass grafts (42 IMA and 92 venous grafts) were analyzed. The angiographically determined patency rate of grafts was 86% for IMA (n = 36 of 42) and 74% for venous grafts (n = 68 of 92). By SCT, 32 IMA and 64 venous grafts were diagnosed correctly as patent. Sensitivity was 89% (IMA) and 94% (venous); overall sensitivity was 92%. None of the truly occluded venous grafts was diagnosed falsely patent by SCT (specificity 100%), whereas the specificity of IMA graft visualization was somewhat lower (88%, p = NS [overall 97%]). The accuracy for a patent graft was 88% (IMA) and 96% (venous CABG, p = NS). Compared with previous studies, these data suggest that SCT using one of the recent generation scanners (single scan time 0.75 second) is a highly accurate and relatively noninvasive approach for assessing not only saphenous vein graft patency, but also IMA graft patency. To date, this technique has only limited use in visualizing graft stenosis or distal anastomosis site patency.

Coronary calcification in long-term type 1 diabetic patients -- a study with multi slice spiral computed tomography.

The risk for cardiovascular disease in diabetes is excessive. Multislice spiral computed tomography (MSCT) is a new technique for the assessment of coronary calcification in coronary artery disease. The aim of the study was to evaluate the presence of coronary calcium in asymptomatic long-term type 1 diabetic patients. Seventy-one type 1 diabetic patients (age 48 +/- 9 y, HbA1c 7.7 +/- 1.2, BMI 24.4 +/- 2.8, duration of diabetes 26 +/- 9 y) without clinical evidence for coronary artery disease were assessed with MSCT. A volumetric score was used to calculate the coronary calcification (CC) score. Five cardiac reflex tests were performed to study patients for cardiac autonomic neuropathy. Coronary calcifications were detectable in 22 (31 %) type 1 diabetic patients (CC-score > 0, mean CC-score 174 +/- 228 [X+/-SD]). Fourty-nine (69 %) type 1 diabetic patients demonstrated no coronary calcifications (CC-score= 0). In patients with coronary calcifications, both cardiac autonomic neuropathy and retinopathy were detected more frequently than in those without (64 % vs. 29 %, p < 0.02; 59 % vs. 31 %; p < 0.02). Duration of diabetes was longer in patients with than without coronary calcification (32 +/- 10 y vs. 24 +/- 8 y, p < 0.01). Age, BMI, and HbA1c were not significantly different between patients with and without coronary calcification. The study demonstrates that nearly one third of asymptomatic long-term type 1 diabetic patients present with coronary calcifications. In the patients, there is evidence for an association between coronary calcification and both cardiac autonomic neuropathy and retinopathy. MSCT is a promising non-invasive approach to analyze early alterations of the coronary system in diabetic patients.

Non-invasive coronary bypass graft imaging after multivessel revascularisation.

Non-invasive imaging techniques for the detection of graft patency after multivessel coronary revascularisation may be useful for follow-up after surgery. Forty consecutive asymptomatic patients (38 men, age 59.9+/-1.3 years) who had undergone coronary bypass surgery with at least three grafts were examined by spiral computed tomography or magnetic resonance angiography 24.9+/-0.3 months after surgery, using conventional angiography as reference. In total, 133 grafts (37 internal mammary artery, 96 venous grafts) were analysed. Spiral computed tomography studies were performed with a subsecond scanner; for magnetic resonance angiography, a three-dimensional contrast-enhanced gradient echo technique with ultrashort echo time during breath holding was used. For spiral computed tomography, sensitivities were 76% (internal mammary artery) and 100% (venous graft). This was compared with 100% (internal mammary artery) and 92% (venous graft) assessed by magnetic resonance angiography (P=ns). The positive predictive values were 100% for internal mammary artery and venous graft (spiral computed tomography) and 100% (internal mammary artery), 92% for venous grafts studied by magnetic resonance angiography (P=ns). Both subsecond spiral computed tomography and contrast-enhanced magnetic resonance angiography are highly accurate and relatively non-invasive approaches of assessing coronary graft patency after multivessel revascularisation and have potential for follow-up assessment in the long term.

Assessment of myocardial perfusion using multisection first-pass MRI and color-coded parameter maps: a comparison to 99mTc Sesta MIBI SPECT and systolic myocardial wall thickening analysis.

The most recently reported magnetic resonance first-pass myocardial perfusion studies were restricted to single slice imaging or a data analysis based on interactively placed regions of interest. This study was designed to investigate a new saturation recovery TurboFLASH sequence for multisection myocardial perfusion imaging and to develop a pixel-based software tool to calculate qualitative perfusion parameters. The findings of perfusion imaging were compared to percent systolic myocardial wall thickening analysis and 99mTc Sesta MIBI SPECT. Six healthy volunteers and twelve patients with proven coronary artery disease (CAD) or chronic myocardial infarction were examined. Diagnostic images were acquired for all volunteers and patients with the multisection saturation recovery TurboFLASH sequence. Perfusion defects could be visualized on parameter maps for signal intensity increase over baseline and signal intensity upslope. Sensitivity and specificity were 76.9% and 97.1% for first-pass perfusion MRI, and respectively 84.6% and 94.3% for CINE imaging. All perfusion defects determined with 99mTc Sesta MIBI SPECT were identified by the combined analysis of myocardial perfusion and wall thickening. The presented software demonstrated a pixel-based analysis of first-pass perfusion studies and simplified image interpretation in a clinical setting. The combination of perfusion and wall motion imaging provided complementary information for the treatment of patients suffering from CAD.

Analysis of beat-to-beat variability of frequency contents in the electrocardiogram using two-dimensional Fourier transforms.

Late potentials are very small signals (1-20 microV) in the surface ECG with high-frequency components, which are found in patients prone to sustained ventricular tachycardia. Evaluation of these signals requires either very sophisticated recording techniques for single-beat analysis or signal averaging. Signal averaging, however, might disregard information about risk stratification. Therefore, we developed the Single-Beat Spectral Variance (SBSV) based on two-dimensional (2-D) Fourier transform of 80 ms segments of 128 consecutive beats. This approach depicts the beat-to-beat variability of the frequency contents of these ECG segments. An index function enables an objective detection of late potentials. We investigated 35 patients after myocardial infarction and sustained ventricular tachycardia (Group 1), 50 patients after myocardial infarction without ventricular arrhythmias (Group 2) and ten healthy volunteers. SBSV classified 29 of 35 patients (83%) of Group 1 as pathologic, 14 of these 29 patients (48%) exclusively on the basis of marked Wenckebach-like conduction pattern. In Group 2, only five of 50 patients showed abnormal SBSV. In Group 3, we found no pathologic result. Thus, SBSV is a promising new method to investigate late potentials in patients after myocardial infarction. SBSV contains not only the results of frequency analysis after signal averaging, but also evaluates variable ECG components.

[Contrast media enhanced magnetic resonance angiography for determining patency of a coronary bypass. A comparison with coronary angiography]. / Kontrastmittelverstärkte Magnetresonanzangiographie zur Uberprüfung der Durchgängigkeit koronarer Bypasses. Vergleich zur Koronarangiographie.

AIM: Assessment of graft patency with current non-invasive MRA techniques is particularly difficult for evaluating internal mammary artery grafts. Our aim is to determine the accuracy of a contrast enhanced MRA technique is assessing graft patency. METHODS: We examined 19 patients with a total of 53 grafts (32 venous/21 arterial), using an ultrafast contrast enhanced 3D gradient-echo technique and compared this with the results of selective angiography. RESULTS: Sensitivity of the contrast enhanced method was 95.2% for venous grafts, 94.4% for IMA grafts and 94.8% overall. Specificity was 85.7% overall, 90.9% for venous and 66.7% for IMA grafts. Positive predictive value was 94.4%. CONCLUSION: Compared with previous studies, visualisation of IMA grafts was improved by using contrast enhanced MRA. In this preliminary study, contrast enhanced MRA proved promising for the assessment of graft patency.

[A comparison of ultrafast computed tomography, magnetic resonance angiography and selective angiography for the detection of coronary bypass patency]. / Vergleich von ultraschneller Computertomographie, Magnetresonanzangiographie und selektiver Angiographie zum Nachweis der Durchgängigkeit koronarer Bypasses.

PURPOSE: Validation of ultrafast-CT and MR-angiography (MRA) in comparison with angiography for detection of early postsurgical arterial and venous coronary artery bypass graft (CABG) patency. METHODS: 21 patients with a total of 55 CABG (34 venous and 21 arterial) were studied with angiography, ultrafast-CT (EBT), and MRA. RESULTS: With EBT, patency of 43/45 angiographically patent CABG could be correctly assessed (sensitivity: 96%). With MRA 26 CABG (17 venous and 9 arterial) were identified as patent (sensitivity: 67%). It was not possible to quantify proximal stenosis of three grafts (> 40%) and to evaluate the distal bypass anastomosis with both EBT and MRA. CONCLUSIONS: Ultrafast-CT is a promising minimal invasive screening method for the evaluation of venous and arterial CABG patency. The diagnostic significance of MRA is remarkably reduced.

[Coronary calcifications and the diagnosis of coronary artery disease]. / Screeningmethode bei asymptomatischen Risikopatienten. Kalkscore als früher Marker der Koronarsklerose.

Coronary calcium is a sensitive marker of coronary atherosclerosis, even at an early stage. With the aid of multislice computed tomography, noninvasive visualization of the microcalcification is possible. This enables the identification of asymptomatic patients at risk of developing future cardiovascular disease, and the initiation of effective preventive measures. In addition, in symptomatic patients, CT angiography with calcium scoring is of high negative predictive value in the exclusion of coronary artery disease.

[Technique and possibilities of cardiac computed tomography]. / Kardiale Mehrzeilen-Computertomographie. Koronarangiographie--ein Auslaufmodell?

Electron beam computed tomography no longer has a role to play in Germany. In contrast, multidetector spiral CT has great potential for replacing some coronary catheter studies, in particular for the exclusion of coronary artery disease, and this in particular since the forthcoming introduction of a 64-slice MDCT scanner promises a further improvement in temporal and special resolution. Currently, however it is no alternative to invasive angiography, since quantification of coronary stenoses is not possible; nor can a diagnostic evaluation be made in the presence of coronary calcifications or intracoronary stents. In particular, however, before applying CT angiography to the heart, the patient groups that can benefit from this method must be defined, especially in light of the fact that radiation exposure is three times as high as with diagnostic coronary catheterization.

[Angiography with multi-slice spiral CT. Detecting plaque, before it causes symptoms]. / Angiographie mit dem Mehrschicht-Spiral-CT. Plaques erkennen, bevor sie Beschwerden machen.

The short imaging time of 1/4 second, renders the new generation of multiple-slice spiral CT devices with ECG gating enables the investigation of the heart without disturbing motion artefacts. With this method, calcifications of the coronary arteries can be detected or excluded. Certain amounts of coronary "chalk" in asymptomatic patients with risk factors point to coronary artery disease and thus a need to modulate the risk factors. With the aid of intravenous injection of contrast medium during the examination, non-calcified plaques in the coronary arteries can also be visualized. A limiting factor is that the patient's heart rate should not exceed 60 beats per minute. Indications for this examination are visualization of coronary vessels with the aim of excluding coronary artery disease, pre-operative planning and monitoring of bypass vessels, and non-invasive follow-up after PTCA and stenting.

[Detection and characterization of atherosclerotic coronary plaques with multislice spiral computed tomography]. / Kardiale Risikostratifizierung: Den atherosklerotischen Plaque im Blick.

Provided that adequate image quality is achieved, contrast-enhanced multislice spiral computed tomography enables the identification and characterisation of calcified and non-calcified coronary plaques. This is a major advance in the non-invasive assessment of coronary atherosclerosis that promises to open up new opportunities for a better understanding and risk stratification of this condition, with visualization of non-calcified hypodense lesions in particular appearing to be of prognostic importance. Current limitations of the technique relating mainly to temporal and spatial resolution may be eliminated by the introduction of a new generation of scanners enabling 64 slices and more.

[Quantification of coronary artery stenoses: comparison of 64-slice and dual source CT angiography with cardiac catheterization]. / Quantifizierung von Stenosen der Koronararterien: 64-Zeilen-CT-Angiographie und Dual Source vs. Herzkatheter.

BACKGROUND: Until now stenoses of the coronary arteries have been evaluated visually with CT angiography. Therefore, the results were highly dependent on subjective factors inherent in the examiner. New software tools for semiquantitative analysis (CT-QCA, quantitative coronary assessment) might be adequate to improve the diagnostic accuracy und reproducibility. MATERIAL AND METHODS: CTAs of 20 patients were analyzed. Ten patients each were evaluated using 64-slice CT (64SCT) and dual source CT (DSCT) (Somatom Sensation 64 and Somatom Definition, Siemens Medical Solutions, Forchheim), respectively. Two radiologists independently evaluated the data visually and with the help of a software tool (Syngo Circulation, Siemens Medical Solutions, Forchheim). The results of the quantitative assessment of the invasive heart catheterization served as the reference standard. Sensitivity and specificity as well as the correlation coefficient, the systematic error, and the interobserver agreement (kappa) were determined. RESULTS: In each of both patient groups 12 stenoses were detected. For the detection of stenoses >75%, sensitivity and specificity for the visual evaluation using the 64SCT were 100% and 90%, and with the CT-QCA both were 100%. For the DSCT sensitivity and specificity were 100% for both the visual and semiautomated evaluation. The Bland-Altman plot of the results of the 64SCT showed an overestimation of 3.3% (+/-62.7%/56.2%) compared to the heart catheterization. The results of the DSCT exhibited an overestimation of 6.2% (+/-33.1%/19.8%). The interobserver agreement of the CT-QCA and the visual evaluation showed a kappa value of 0.75 and for DSCT of 1.0. CONCLUSION: The results showed a good correlation of grading stenosis between the software-assisted evaluation and the results of the coronary catheter angiography. The promising results of the DSCT are due to a superior temporal resolution compared to the 64SCT. Confirmation of these data by trials in larger patient collectives is warranted.

[Dual-source CT in chest pain diagnosis]. / Dual-source-CT in der Diagnostik des Thoraxschmerzes.

BACKGROUND: With the depiction of pulmonary arteries, coronary arteries, and the aorta, CT angiography of the chest offers a comprehensive diagnostic work-up of unclear chest pain. The aim of this study was to assess the diagnostic accuracy of dual-source CT in this patient group. MATERIALS AND METHODS: A total of 47 patients suffering from unclear chest pain were examined with a Siemens Somatom Definition. Volume and flow of contrast media (Ultravist, Schering) were adapted to the body weight. The examinations were evaluated with regard to image quality and contrast opacification and to the diagnostic accuracy with reference to the final clinical diagnosis. RESULTS: Adequate contrast opacification was achieved in all examinations. The depiction of the coronary arteries was diagnostic in all cases. The cause of chest pain could be identified in 41 cases. Among the diagnoses were coronary and myocardial pathologies, valvular disease, aortic aneurysms and dissections, pulmonary embolism, and pneumonic consolidation. CONCLUSION: DSCT angiography of the chest offers a very good image quality even at high heart rates so that a high diagnostic accuracy is achieved in patients with acute chest pain.