Discordance between anatomical and functional coronary stenosis severity.

BACKGROUND.: New developments have made 16-slice multidetector computed tomography (MDCT) a promising technique for detecting significant coronary stenoses. At present, there is a paucity of data on the relation between fractional flow reserve (FFR) measurement and MDCT stenosis detection. OBJECTIVE.: The aim of this study was to investigate the relation between the anatomical severity of coronary artery disease detected by MDCT and functional severity measured by fractional flow reserve (FFR). METHODS.: We studied 53 patients (39 men and 14 women, age 62.5+/-8.1 years) with single-vessel disease scheduled for percutaneous coronary intervention (PCI). All patients underwent MDCT scanning one day prior to PCI and FFR was measured before PCI in the target vessel. RESULTS.: MDCT analysis could be performed in 52 of 53 patients (98.1%) and all patients had adequate FFR and quantitative coronary angiography (QCA) measurements. The mean stenosis diameters calculated by MDCT and QCA were 67.0+/-11.6% and 60.8+/-11.6% respectively. No significant relation was found between MDCT and QCA (r=0.22, p=0.12) The mean FFR in all patients was 0.67+/-0.18. A relation of r=-0.46 (p=0.0006) between QCA and FFR was found. In contrast, no relation between MDCT and FFR could be demonstrated (r=-0.09, p=0.50). Furthermore, a high incidence of false-positive and false-negative findings was present in both diagnostic modalities. CONCLUSION.: There is no clear relation between the anatomical and functional severity of coronary artery disease as defined by MDCT and FFR. Therefore, functional assessment of coronary artery disease remains mandatory for clinical decisionmaking. (Neth Heart J 2007;15:5-11.).

Assessment of coronary artery bypass graft patency by multidetector computed tomography and electron-beam tomography.

This case report describes the use of retrospectively ECG-gated 16-slice multidetector computed tomography (MDCT) and electron-beam tomography (EBT) for assessing bypass graft patency in two patients with recurrent angina after coronary artery bypass graft surgery. The results of each tomographic modality were compared to the findings of traditional coronary angiography. In the first patient MDCT showed occlusion of the left internal mammary artery (LIMA) and saphenous vein graft after the second anastomosis. Coronary angiography confirmed these findings. In the second patient EBT showed patency of the LIMA and saphenous vein graft. After the first anastomosis of the saphenous vein graft, the connected vessel filled poorly. Coronary angiography confirmed both grafts to be patent, and detected an occlusion distal to the first anastomosis. These findings support the evidence that both MDCT and EBT are suitable techniques for establishing bypass graft patency by non-invasive means.

A 16-slice multidetector computed tomography protocol for evaluation of the gastroepiploic artery grafts in patients after coronary artery bypass surgery.

Arterial coronary bypass grafts [internal mammary arteries and gastroepiploic artery (GEA)] are in widespread use for coronary surgery. Since selective catheterisation of the GEA graft to monitor patency, is often unsuccessful, a non-invasive protocol to visualise the GEA-graft from origin to anastomosis is presented using 16-slice multidetector computed tomography (MDCT). Twenty-six male patients (mean age 58.1+/-6.7 years) with GEA grafts were scanned according to a protocol of an ECG-synchronised cardiac scan followed by a thoracoabdominal scan. To terminate the scan at the correct anatomical level, the lowest level of the GEA was coded based on the lumbar vertebrae level. Scores ranging from one (excellent) to four (bad) were assigned to evaluate visualisation quality of the grafts. GEA grafts were assessable in 62% of the thoracoabdominal scans and 69% of the cardiac scans. On average, the lowest part of the GEA corresponded with a level between L1 and L2, in two cases in the upper part of L3. Mean visualisation score in the thoracoabdominal scans and cardiac scans was good (respectively 1.4+/-0.6 and 1.4+/-1.0). Sixteen-slice MDCT is a promising alternative for catheterisation in evaluating patency of GEA grafts, using the presented protocol with thoracoabdominal scan including L3 for complete coverage of the GEA graft.

Multidetector computed tomography-guided treatment strategy in patients with non-ST elevation acute coronary syndromes: a pilot study.

Patients with non-ST elevation acute coronary syndrome (ACS) and evidence of myocardial ischaemia are scheduled for coronary angiography (CAG). In most patients CAG remains a single diagnostic procedure only. A prospective study was performed to evaluate whether 16-slice multidetector CT (MDCT) could predict treatment of the patients and to determine how many CAGs could have been prevented by MDCT scanning prior to CAG. Twenty-two patients with ACS were scanned prior to CAG. Based on MDCT data, a fictive treatment was proposed and compared to CAG-based treatment. Excellent accuracy was observed to detect significant stenoses using MDCT (sensitivity 94%, specificity 96%). In 45%, no PCI was performed during CAG, because of the absence of significant coronary artery disease (27%) or severe coronary artery disease, demanding CABG (18%). MDCT predicted correct treatment in 86%. By using MDCT data, 32% of the CAGs could have been prevented.

[The role of multidetector computed tomography in the diagnosis in 3 patients with ischaemic heart complaints]. / De rol van multidetector-CT in de diagnostiek bij 3 patiënten met ischemische hartklachten.

Multidetector CT (MDCT) can provide important information before or after coronary angiography (CAG). This is illustrated by three cases. In a 21-year-old female with ventricle fibrillation CAG demonstrated an anomalous right coronary artery, the exact course of which could not be evaluated. MDCT demonstrated a course between the aorta and pulmonary trunk with vessel compression during systole. After a bypass operation and subsequent pacemaker implantation, she was asymptomatic at follow-up six weeks after hospital discharge. In a 46-year-old male with chest pain, MDCT showed triple vessel disease after which percutaneous coronary intervention (PCI) with stent implantation of the three main branches was performed. Two months after discharge, the patient did not report any complaints. In a 51-year-old male scheduled for PCI of the left anterior descending coronary artery (LAD), MDCT detected a LAD thrombus with 90% occlusion prior to PCI. The occlusion was confirmed during CAG and treated with angioplasty. The next day he was discharged. MDCT offers a practical solution for different cardiac problems through its high diagnostic value.

[Multidetector computed tomography of the coronary arteries]. / Multidetectorcomputertomografie van de kransslagaderen.

In the past decade, improvements in CT techniques have enabled non-invasive visualization of the coronary arteries. Multidetector CT (MDCT) is currently the generally accepted technique for the follow-up of coronary stents and by-pass grafts, and for the evaluation of anomalous coronary arteries and coronary artery disease. Both the degree of stenosis, as well as plaque composition can be determined by MDCT. Plaque composition has proven to be a more important predictor for acute coronary syndromes than the degree of stenosis. In addition, MDCT has less risks of complication and lower costs. Limitations of MDCT are: sensitivity to rhythm- and breathing artefacts, a lower spatial and time resolution than coronary angiography (CAG), and difficulties in coronary evaluation close to high density structures such as calcifications and stents. Coronary angiography is still indicated when functional information has to be obtained about coronary flow. MDCT should be considered in all cases in which diagnostic CAG is performed.

Taekling the challenges of interpretation of conventional coronary angiography using multidetector CT coronary angiography.

BACKGROUND: Although conventional catheter angiography is still regarded as the gold standard for anatomical visualisation of the coronary artery tree, it faces a number of challenges and pitfalls concerning the interpretation of the acquired images. AIM: The aim of this review is to demonstrate that multidetector computed tomography (MDCT) can provide information that is not or only partially acquired by coronary angiography (CAG). METHODS: For different interpretation issues and pitfalls, we establish whether MDCT can provide better, i.e. more standardised and reproducible, information on the basis of both the properties of the technique and clinical examples. RESULTS: Advantages of MDCT are full three- and four-dimensional coverage of the heart and contrast enhancement of all vascular compartments together with a superior low contrast resolution. MDCT shortcomings are the low temporal resolution and related to this the lack of flow information compared with catheter coronary angiography. MDCT is shown to meet most of the blind spots and pitfalls described for catheter coronary angiography. CONCLUSION: Cardiac and coronary MDCT provides diagnostic information, which equals CAG diagnosis in most cases, and in some cases even provides a better diagnosis. This could influence the value of the sensitivity and specificity numbers published comparing noninvasive techniques with catheter coronary angiography (gold standard). Due to the added advantages of CT and its continuous improvement of temporal and spatial resolution, it might eventually replace diagnostic catheter coronary angiography.