Interuniversity Cardiology Institute of the Netherlands
CT
imaging
of
the heart
J.D. Schuijf, J.W. Jukema, J.J. Bax
Figure 1. Noninvasive visualisation of the coronaty artries with 64-slice MSCT. Leftpanel: curped multiplanar reconstrction of the left anterior descending coronary artery, sbowing the abwnce ofsignificantstenosis. Middk panek 3D volume rendered reconstrction. Right panel:coespondinginvaivecoronaryangiogram, confirmingthe absnce ofsignifpcantswenis. 3D VR-3D volume renderd reconmsttion, CAG-conventional coronary angiograpky, cMPR=curved multiplanar rconstruction, Difirst diagona4 LAD-left anterior descending coronaryartery, LCA=lkft coronaryartry, LCxI kft circumflexcoronaryartey, LM=lkft main coronaryartery, RCA=rightcoronaryartery.
Considering the fact that up to 40% of diagnostic catheterisations are not followed by an intervention, noninvasive visualisation ofthe coronary arteries has long been the ultimate goal of noninvasive imaging techniques. J.D. Schulif J.W. Jukema JJ. Bax Department of Cardiology, Leiden University Medical Centre, Leiden, and the Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands
Correspondence to: J.W. Jukema Department of Cardiology, Leiden University Medical Centre, PO Box 9600, 2600 RC Leiden, the Netherlands E-mail: [email protected]
440
In the project 'Cardiac MRI and MSCT in the noninvasive assessment of coronary artery disease' supported by the International Cardiology Institute of the Netherlands and the Netherlands Heart Foundation, both magnetic resonance imaging (MRI) and computed tomography techniques are under investigation for this purpose. At present the latter appears to be the most robust technique, as recently underlined by a meta-analysis of the available literature on noninvasive coronary angiography with MRI and multi-slice computed tomography (MSCT) to detect significant stenoses as compared with invasive coronary angiography.1 Comparison of average weighted sensitivities and specificities based on 51 studies demonstrated significantly higher values for MSCT (weighted average 85%, 95% CI 86-88%, and 95%, 95% CI 95%) as compared with MRI (weighted average 72%, 95% CI 69-75%, and 87%, 95% CI 86-88%). Also, a significantly higher odds ratio (16.9-fold) for the presence of signifiNethrlandls Heart Journal, Volue 14, Number 12, Dccembcr 2006
Interuniversity Cardiology Institute of the Netherlands cant stenosis was obtained for MSCT versus MRI (6.4-fold) (p< 0.0001), indicating that at present, MSCT is more accurate in detecting significant coronary artery stenoses compared with MRI. More recently, the diagnostic accuracy of64-slice MSCT was evaluated in 61 patients, one ofwhom had to be exduded due to a heart rate >90 beats/min.2 In the remaining patients, 854 segments were available for evaluation. Ofthese segments 842 (99%) were of sufficient image quality. Conventional coronary angiography identified 73 lesions, 62 ofwhich were detected by MSCT. Corresponding sensitivity and specificity were 85 and 97%, respectively. On a patient basis, sensitivity and specificity were 94 and 97% respectively, indicating that 64-slice MSCT enables accurate and noninvasive evaluation of significant coronary artery stenoses. In figure 1, an example of a patient without significant stenosis imaged with 64-slice MSCT is provided.
However, it is important to realise that thus far, the majority ofdata on this technique have been obtained in patients with a high pretest likelihood of CAD, as only patients were evaluated who had already been referred for invasive coronary angiography. In contrast the technique is more likely to be implemented in patients with a lower pre-test likelihood; patients who are referred for further evaluation because of the presence ofatypical symptoms in combination with several risk factors for CAD. Accordingly, it is important to establish whether risk factors may influence the diagnostic accuracy of MSCT. Recently, this issue was addressed in a combined investigation performed by the Erasmus Medical Centre and the Leiden University Medical Centre.3 In 197 patients, referred for invasive coronary angiography, an overall sensitivity and specificity of 99 and 86% were observed for 16-slice MSCT. Importantly, no significant differences were observed in the presence of diabetes, hypertension, hypercholesterolaemia or obesity, indicating that coronary risk factors may not influence coronary assessment with MSCT.
Still, this investigation was also performed predominantly in patients with a high pretest likelihood, as reflected by the high prevalence (83%) of CAD during invasive coronary angiography. In addition, few data are available on how the technique relates to functional imaging, which constitutes the traditional first-line imaging step in patients presenting with suspected CAD. To answer these questions, a total of 114
Netherlands Heart Journal, Volume 14, Number 12, December 2006
patients, 50 of whom were females, at intermediate risk for CAD were prospectively enrolled at the Leiden University Medical Centre and the Cardiovascular Centre of Aalst.4 All patients underwent both myocardial perfusion imaging by means of gated single photon emission CT (SPECT) and MSCT. A good agreement was shown between a completely normal MSCT examination and myocardial perfusion imaging (MPI) results as normal myocardial perfusion was observed in patients without any evidence of atherosclerosis on MSCT. In patients with atherosclerosis on MSCT (regardless of severity), however, an abnormal MPI was obtained in 45%. Still, even when patients with at least one significant stenosis were considered, normal perfusion was encountered in 50%. In a subset of58 patients, invasive coronary angiography was also performed showing an excellent agreement of 90% between invasive coronary angiography and MSCT, confirming the accuracy ofMSCT in populations with a lower pre-test likelihood. Importantly, all patients classified as either normal or having nonobstructive CAD were correctly identified, supporting the role ofMSCT to rule out significant lesions. However, as only halfof observed stenoses on MSCT may have haemodynamic relevance, the current observations indicate that in patients with abnormal MSCT examinations functional testing remains mandatory to determine further clinical management. Clearly further investigations are needed to support these observations, while also follow-up data need to be acquired to allow optimal integration ofMSCT coronary angiography in the clinical work-up of patients with suspected CAD. . References Schuijf JD, Bax JJ, Shaw LJ, de Roos A, Lamb HJ, van der Wall EE, et al. Meta-analysis of comparative diagnostic performance of magnetic resonance imaging and multislice computed tomography for noninvasive coronary angiography. Am HeartJ2006;151:404-11. 2 Schuijf JD, Pundziute G, Jukema JW, Lamb HJ, van der Hoeven BL, de Roos A, et al. Diagnostic accuracy of64-slice multislice computed tomography in the noninvasive evaluation ofsignificant coronary artery disease. Am JCardiol2006;98:145-8. 3 Schuijf JD, Mollet NR, Cademartiri F, Jukema JW, Lamb HJ, de Roos A, et al. Do risk factors influence the diagnostic accuracy of noninvasive coronary angiography with multislice computed tomography? JNucl Cardiol 2006;13:635-41. 4 Schuijf JD, Wijns W, Jukema JW, Atsma, DE, Lamb HJ, Stokkel MP, et al. Relationship between non-invasive coronary angiography with multislice computed tomography and myocardial perfusion imaging. JAm Coll CardioI2006 [in press]. 1
441
CT
imaging
of
the heart
J.D. Schuijf, J.W. Jukema, J.J. Bax
Figure 1. Noninvasive visualisation of the coronaty artries with 64-slice MSCT. Leftpanel: curped multiplanar reconstrction of the left anterior descending coronary artery, sbowing the abwnce ofsignificantstenosis. Middk panek 3D volume rendered reconstrction. Right panel:coespondinginvaivecoronaryangiogram, confirmingthe absnce ofsignifpcantswenis. 3D VR-3D volume renderd reconmsttion, CAG-conventional coronary angiograpky, cMPR=curved multiplanar rconstruction, Difirst diagona4 LAD-left anterior descending coronaryartery, LCA=lkft coronaryartry, LCxI kft circumflexcoronaryartey, LM=lkft main coronaryartery, RCA=rightcoronaryartery.
Considering the fact that up to 40% of diagnostic catheterisations are not followed by an intervention, noninvasive visualisation ofthe coronary arteries has long been the ultimate goal of noninvasive imaging techniques. J.D. Schulif J.W. Jukema JJ. Bax Department of Cardiology, Leiden University Medical Centre, Leiden, and the Interuniversity Cardiology Institute of the Netherlands, Utrecht, the Netherlands
Correspondence to: J.W. Jukema Department of Cardiology, Leiden University Medical Centre, PO Box 9600, 2600 RC Leiden, the Netherlands E-mail: [email protected]
440
In the project 'Cardiac MRI and MSCT in the noninvasive assessment of coronary artery disease' supported by the International Cardiology Institute of the Netherlands and the Netherlands Heart Foundation, both magnetic resonance imaging (MRI) and computed tomography techniques are under investigation for this purpose. At present the latter appears to be the most robust technique, as recently underlined by a meta-analysis of the available literature on noninvasive coronary angiography with MRI and multi-slice computed tomography (MSCT) to detect significant stenoses as compared with invasive coronary angiography.1 Comparison of average weighted sensitivities and specificities based on 51 studies demonstrated significantly higher values for MSCT (weighted average 85%, 95% CI 86-88%, and 95%, 95% CI 95%) as compared with MRI (weighted average 72%, 95% CI 69-75%, and 87%, 95% CI 86-88%). Also, a significantly higher odds ratio (16.9-fold) for the presence of signifiNethrlandls Heart Journal, Volue 14, Number 12, Dccembcr 2006
Interuniversity Cardiology Institute of the Netherlands cant stenosis was obtained for MSCT versus MRI (6.4-fold) (p< 0.0001), indicating that at present, MSCT is more accurate in detecting significant coronary artery stenoses compared with MRI. More recently, the diagnostic accuracy of64-slice MSCT was evaluated in 61 patients, one ofwhom had to be exduded due to a heart rate >90 beats/min.2 In the remaining patients, 854 segments were available for evaluation. Ofthese segments 842 (99%) were of sufficient image quality. Conventional coronary angiography identified 73 lesions, 62 ofwhich were detected by MSCT. Corresponding sensitivity and specificity were 85 and 97%, respectively. On a patient basis, sensitivity and specificity were 94 and 97% respectively, indicating that 64-slice MSCT enables accurate and noninvasive evaluation of significant coronary artery stenoses. In figure 1, an example of a patient without significant stenosis imaged with 64-slice MSCT is provided.
However, it is important to realise that thus far, the majority ofdata on this technique have been obtained in patients with a high pretest likelihood of CAD, as only patients were evaluated who had already been referred for invasive coronary angiography. In contrast the technique is more likely to be implemented in patients with a lower pre-test likelihood; patients who are referred for further evaluation because of the presence ofatypical symptoms in combination with several risk factors for CAD. Accordingly, it is important to establish whether risk factors may influence the diagnostic accuracy of MSCT. Recently, this issue was addressed in a combined investigation performed by the Erasmus Medical Centre and the Leiden University Medical Centre.3 In 197 patients, referred for invasive coronary angiography, an overall sensitivity and specificity of 99 and 86% were observed for 16-slice MSCT. Importantly, no significant differences were observed in the presence of diabetes, hypertension, hypercholesterolaemia or obesity, indicating that coronary risk factors may not influence coronary assessment with MSCT.
Still, this investigation was also performed predominantly in patients with a high pretest likelihood, as reflected by the high prevalence (83%) of CAD during invasive coronary angiography. In addition, few data are available on how the technique relates to functional imaging, which constitutes the traditional first-line imaging step in patients presenting with suspected CAD. To answer these questions, a total of 114
Netherlands Heart Journal, Volume 14, Number 12, December 2006
patients, 50 of whom were females, at intermediate risk for CAD were prospectively enrolled at the Leiden University Medical Centre and the Cardiovascular Centre of Aalst.4 All patients underwent both myocardial perfusion imaging by means of gated single photon emission CT (SPECT) and MSCT. A good agreement was shown between a completely normal MSCT examination and myocardial perfusion imaging (MPI) results as normal myocardial perfusion was observed in patients without any evidence of atherosclerosis on MSCT. In patients with atherosclerosis on MSCT (regardless of severity), however, an abnormal MPI was obtained in 45%. Still, even when patients with at least one significant stenosis were considered, normal perfusion was encountered in 50%. In a subset of58 patients, invasive coronary angiography was also performed showing an excellent agreement of 90% between invasive coronary angiography and MSCT, confirming the accuracy ofMSCT in populations with a lower pre-test likelihood. Importantly, all patients classified as either normal or having nonobstructive CAD were correctly identified, supporting the role ofMSCT to rule out significant lesions. However, as only halfof observed stenoses on MSCT may have haemodynamic relevance, the current observations indicate that in patients with abnormal MSCT examinations functional testing remains mandatory to determine further clinical management. Clearly further investigations are needed to support these observations, while also follow-up data need to be acquired to allow optimal integration ofMSCT coronary angiography in the clinical work-up of patients with suspected CAD. . References Schuijf JD, Bax JJ, Shaw LJ, de Roos A, Lamb HJ, van der Wall EE, et al. Meta-analysis of comparative diagnostic performance of magnetic resonance imaging and multislice computed tomography for noninvasive coronary angiography. Am HeartJ2006;151:404-11. 2 Schuijf JD, Pundziute G, Jukema JW, Lamb HJ, van der Hoeven BL, de Roos A, et al. Diagnostic accuracy of64-slice multislice computed tomography in the noninvasive evaluation ofsignificant coronary artery disease. Am JCardiol2006;98:145-8. 3 Schuijf JD, Mollet NR, Cademartiri F, Jukema JW, Lamb HJ, de Roos A, et al. Do risk factors influence the diagnostic accuracy of noninvasive coronary angiography with multislice computed tomography? JNucl Cardiol 2006;13:635-41. 4 Schuijf JD, Wijns W, Jukema JW, Atsma, DE, Lamb HJ, Stokkel MP, et al. Relationship between non-invasive coronary angiography with multislice computed tomography and myocardial perfusion imaging. JAm Coll CardioI2006 [in press]. 1
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