Circulation. 2006;114:e237-e239
doi: 10.1161/CIRCULATIONAHA.105.601369
(Circulation. 2006;114:e237-e239.)
© 2006 American Heart Association, Inc.
Images in Cardiovascular Medicine |
Hybrid Cardiac Single Photon Emission Computed Tomography/Computed Tomography Imaging With Myocardial Perfusion Single Photon Emission Computed Tomography and Multidetector Computed Tomography Coronary Angiography for the Assessment of Unstable Angina Pectoris After Coronary Artery Bypass Grafting
Eduard Ghersin, MD;
Zohar Keidar, MD, PhD;
Shmuel Rispler, MD, PhD;
Diana Litmanovich, MD;
Rachel Bar-Shalom, MD;
Ariel Roguin, MD;
Adrian Soil, MSc;
Ora Israel, MD;
Ahuva Engel, MD
From the Departments of Diagnostic Imaging (E.G., D.L., A.E.), Nuclear Medicine (Z.K., R.B.-S., O.I.), and Cardiology (S.R., A.R.), Rambam Health Care Campus, B. Rapaport School of Medicine, Technion, Israel, and Institute of Technology (E.G., Z.K., R.B.-S., A.R., O.I., A.E.) and GE Healthcare Technologies (A.S.), Haifa, Israel.
Correspondence to Eduard Ghersin, MD, Department of Diagnostic Imaging, Rambam Medical Center, 6 Haalya Hashnia St, Haifa 31096, Israel. E-mail e_ghersin{at}rambam.health.gov.il
A 73-year-old man was admitted to the cardiology department because of recent-onset angina pectoris. The patient had undergone coronary artery bypass graft surgery 10 years earlier with a left internal mammary artery graft to the left anterior descending artery and 4 saphenous vein grafts to the distal right coronary, first marginal, ramus intermedius, and first diagonal coronary arterial segments, respectively. Three years before the current admission, the patient developed recurrent angina pectoris and underwent angioplasty with stenting of the saphenous vein graft to the first diagonal artery. Because of recurrent symptoms on admission, the patient was referred for noninvasive assessment of the current status of his coronary artery disease with the use of a combined single photon emission computed tomography (SPECT)/computed tomography (CT) research system (Infinia LightSpeed, GE Healthcare Technologies, Milwaukee, Wis) that includes a dual-head variable-angle gamma camera and a 16-slice CT scanner. These components share a common table and are spatially aligned to enable sequential acquisition of both myocardial perfusion imaging and CT coronary angiography (CTCA) without patient motion between the procedures. Myocardial perfusion-gated SPECT studies were acquired using 130 MBq (3.5 mCi) Thallium for rest imaging and 925 MBq (25mCi) technetium 99m sestamibi for stress scintigraphy. The CTCA component of the examination was acquired during a 20-second breathhold at full inspiration with the use of a detector collimation of 16x1.25 mm, a rotation time of 0.5 sec, a tube voltage of 120 kV, and a current of 420 mA.
The Tl-201/technetium 99m sestamibi SPECT study was processed on an Xeleris workstation and the multidetector CT study on an Advantage Workstation (both GE Healthcare Technologies).
Curved multiplanar reformats of CTCA depicted a tight, irregular stenosis of the proximal saphenous vein graft to the first diagonal artery, just proximal to a patent stent that had been inserted 3 years earlier. The other 4 grafts were demonstrated to be patent across their entire lengths (Figures 1 and 2
). Myocardial perfusion SPECT images demonstrated the presence of a reversible perfusion defect involving the anterolateral segment, consistent with myocardial ischemia in that area (Figure 3).
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Figure 1. Focused image of a volume-rendered CT angiogram demonstrates 3 out of 5 bypass grafts, including saphenous vein grafts to the first marginal (white dotted arrow), ramus intermedius (white arrowhead), and first diagonal (black arrowhead) coronary arterial segments, respectively. Note a suggested stenosis in the proximal portion of the graft to the first diagonal artery (black arrowhead) proximal to an endovascular stent (black dotted arrow).
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Figure 2. A and B, Corresponding curved planar reformations in 2 different projections of the saphenous vein graft to the first diagonal artery demonstrate severe irregular stenosis (solid white arrow) proximal to a patent stent (black arrow). Note the patent diagonal artery distal to the anastomosis with the saphenous vein graft (dotted white arrow).
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Figure 3. Cardiac perfusion SPECT study at stress (first and third rows) and rest (second and forth rows) shows reversible perfusion defect in the anterolateral wall (arrows) consistent with myocardial ischemia. The perfusion study has been corrected for attenuation by using maps computed from low-dose CT scans. The color convention used shows normal perfusion in brighter colors and decreased perfusion in darker colors.
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Fusion of the native coronary arterial tree extracted from the CTCA study with the left ventricle epicardial surface derived from the myocardial perfusion SPECT study was performed using the application HeartFusion (Emory University, Atlanta, Ga). The fused images associated the large reversible perfusion defect in the anterolateral LV wall with the vascular territory of the first diagonal artery (Figure 4). On the basis of this information, revascularization of the severely stenosed bypass graft was performed with balloon angioplasty and stenting (Figure 5). The patient was discharged 24 hours after the procedure after complete clinical recovery.
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Figure 4. Combined data of myocardial perfusion (represented on the left ventricle epicardial surface extracted from the SPECT study) and the native left coronary tree. The left image, at stress, shows decreased perfusion in the anterolateral wall (blue region, arrow) corresponding to the vascular territory of the first diagonal artery (arrow head). Fused data at rest (right) show normal perfusion to the same area (dotted arrow). The fused information generated from the perfusion SPECT study and the coronary CT angiography is consistent with myocardial ischemia related to a tight, irregular stenosis of the proximal saphenous vein graft to the first diagonal artery (shown in Figure 2). LAD indicates left anterior descending coronary; D1, first diagonal branch; R, ramus intermedius coronary; and LCX, left circumflex coronary.
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Figure 5. Selective invasive angiography of the saphenous vein graft to the first diagonal artery confirms severe stenosis of the graft (arrow) proximal to a patent coronary stent (dotted arrow).
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Acknowledgments
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Disclosures
A. Soil is an employee of and Dr Israel is a consultant for GE Healthcare Technologies.
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