DOI: 10.1148/rg.252045098
Pitfalls in 16–Detector Row CT of the Coronary Arteries1
Tadashi Nakanishi, MD,
Yasuyo Kayashima, MD,
Rintaro Inoue, MD,
Kotaro Sumii, MD and
Yukihiko Gomyo, MD
1 From the Departments of Radiology (T.N., Y.K.) and Cardiology (R.I., K.S., Y.G.), Mazda Hospital, Mazda Motor Corporation, 2–15 Aosakiminami, Fuchu-cho, Aki-gun, Hiroshima 735-8585, Japan. Presented as an education exhibit at the 2003 RSNA Scientific Assembly. Received May 3, 2004; revision requested June 16 and received July 28; accepted July 29. All authors have no financial relationships to disclose.
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Figure 1a. High-quality MPR images obtained from coronary CT angiographic data sets with excellent structural consistency. The patient, a 41-year-old woman, had an average heart rate of 48 bpm during CT angiography. (a) Axial image obtained at the midventricular level shows a round enhanced area representing the right coronary artery (RCA). No motion artifact is seen. (b, c) Coronal (b) and sagittal (c) images show no undulating contours at the cardiac border.
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Figure 1b. High-quality MPR images obtained from coronary CT angiographic data sets with excellent structural consistency. The patient, a 41-year-old woman, had an average heart rate of 48 bpm during CT angiography. (a) Axial image obtained at the midventricular level shows a round enhanced area representing the right coronary artery (RCA). No motion artifact is seen. (b, c) Coronal (b) and sagittal (c) images show no undulating contours at the cardiac border.
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Figure 1c. High-quality MPR images obtained from coronary CT angiographic data sets with excellent structural consistency. The patient, a 41-year-old woman, had an average heart rate of 48 bpm during CT angiography. (a) Axial image obtained at the midventricular level shows a round enhanced area representing the right coronary artery (RCA). No motion artifact is seen. (b, c) Coronal (b) and sagittal (c) images show no undulating contours at the cardiac border.
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Figure 2. Volume-rendered (VR) images obtained from coronary CT angiographic data sets with excellent structural consistency. The main coronary artery branches can be easily visualized once the main pulmonary artery, right atrium (RA), and left atrial appendage (LAA) are removed. VR findings can be compared with and used to validate findings at catheter angiography, since an arbitrary view angle can be set. RV = right ventricle.
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Figure 3a. Pulsation artifacts. (a, b) Left anterior oblique (a) and anterior (b) MPR images clearly demonstrate a kymographic gap along the RCA with moderate motion artifacts at the mid-RCA. (c) Left anterior oblique thin-slab maximum-intensity-projection (MIP) image is suspicious for mild stenosis at the mid-RCA (arrow). (d) Anterior thin-slab MIP image shows definite motion artifacts (arrows), which appear to create pseudostenosis at the mid-RCA. In theory, MIP obscures a kymographic gap perpendicular to the slab plane, since the appearances of thin-slab MIP images depend on slab thickness and the orientation of the vessel of interest relative to the slab plane.
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Figure 3b. Pulsation artifacts. (a, b) Left anterior oblique (a) and anterior (b) MPR images clearly demonstrate a kymographic gap along the RCA with moderate motion artifacts at the mid-RCA. (c) Left anterior oblique thin-slab maximum-intensity-projection (MIP) image is suspicious for mild stenosis at the mid-RCA (arrow). (d) Anterior thin-slab MIP image shows definite motion artifacts (arrows), which appear to create pseudostenosis at the mid-RCA. In theory, MIP obscures a kymographic gap perpendicular to the slab plane, since the appearances of thin-slab MIP images depend on slab thickness and the orientation of the vessel of interest relative to the slab plane.
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Figure 3c. Pulsation artifacts. (a, b) Left anterior oblique (a) and anterior (b) MPR images clearly demonstrate a kymographic gap along the RCA with moderate motion artifacts at the mid-RCA. (c) Left anterior oblique thin-slab maximum-intensity-projection (MIP) image is suspicious for mild stenosis at the mid-RCA (arrow). (d) Anterior thin-slab MIP image shows definite motion artifacts (arrows), which appear to create pseudostenosis at the mid-RCA. In theory, MIP obscures a kymographic gap perpendicular to the slab plane, since the appearances of thin-slab MIP images depend on slab thickness and the orientation of the vessel of interest relative to the slab plane.
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Figure 3d. Pulsation artifacts. (a, b) Left anterior oblique (a) and anterior (b) MPR images clearly demonstrate a kymographic gap along the RCA with moderate motion artifacts at the mid-RCA. (c) Left anterior oblique thin-slab maximum-intensity-projection (MIP) image is suspicious for mild stenosis at the mid-RCA (arrow). (d) Anterior thin-slab MIP image shows definite motion artifacts (arrows), which appear to create pseudostenosis at the mid-RCA. In theory, MIP obscures a kymographic gap perpendicular to the slab plane, since the appearances of thin-slab MIP images depend on slab thickness and the orientation of the vessel of interest relative to the slab plane.
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Figure 4a. Pulsation artifacts. (a) Left anterior oblique coronary catheter angiogram demonstrates no significant stenosis at the RCA. Image reformation was performed to optimize coronary CT angiography. (b, c) Thin-slab MIP images created from data obtained in different cardiac cycles show different findings. In data sets with the reformation window starting 400 msec prior to the next R wave, apparent section gaps are observed (arrowheads in b), whereas mild stenosis seems to exist in data sets with the reformation window starting 200 msec prior to the next R wave (arrowhead in c).
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Figure 4b. Pulsation artifacts. (a) Left anterior oblique coronary catheter angiogram demonstrates no significant stenosis at the RCA. Image reformation was performed to optimize coronary CT angiography. (b, c) Thin-slab MIP images created from data obtained in different cardiac cycles show different findings. In data sets with the reformation window starting 400 msec prior to the next R wave, apparent section gaps are observed (arrowheads in b), whereas mild stenosis seems to exist in data sets with the reformation window starting 200 msec prior to the next R wave (arrowhead in c).
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Figure 4c. Pulsation artifacts. (a) Left anterior oblique coronary catheter angiogram demonstrates no significant stenosis at the RCA. Image reformation was performed to optimize coronary CT angiography. (b, c) Thin-slab MIP images created from data obtained in different cardiac cycles show different findings. In data sets with the reformation window starting 400 msec prior to the next R wave, apparent section gaps are observed (arrowheads in b), whereas mild stenosis seems to exist in data sets with the reformation window starting 200 msec prior to the next R wave (arrowhead in c).
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Figure 5a. Artifacts due to increased heart rate in a 46-year-old woman. The patient experienced alterations in heart rate in normal sinus rhythm during scanning, which was performed shortly after the sublingual administration of nitroglycerin. The patient’s average heart rate was 51 bpm, increasing to 69 bpm in the last third of the acquisition. Coronal (a) and sagittal (b) reformatted images of the heart obtained from CT data demonstrate banding artifacts (arrowheads), which were observed only in the last third.
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Figure 5b. Artifacts due to increased heart rate in a 46-year-old woman. The patient experienced alterations in heart rate in normal sinus rhythm during scanning, which was performed shortly after the sublingual administration of nitroglycerin. The patient’s average heart rate was 51 bpm, increasing to 69 bpm in the last third of the acquisition. Coronal (a) and sagittal (b) reformatted images of the heart obtained from CT data demonstrate banding artifacts (arrowheads), which were observed only in the last third.
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Figure 6a. Excellent coronary angiograms of the RCA (a) and LAD artery (b) obtained in a 65-year-old woman in atrial fibrillation. The fibrillation was causing a variable R-R interval, probably because of the relatively long R-R interval.
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Figure 6b. Excellent coronary angiograms of the RCA (a) and LAD artery (b) obtained in a 65-year-old woman in atrial fibrillation. The fibrillation was causing a variable R-R interval, probably because of the relatively long R-R interval.
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Figure 7a. Artifacts due to incomplete breath holding. (a) Contiguous sections demonstrate almost no motion artifacts when each image is observed separately. (b, c) Coronal (b) and sagittal (c) reformatted images demonstrate banding artifacts with kymographic contours at the cardiac border. The patient had a heart rate of 58 bpm in normal sinus rhythm during scanning. Later, it was discovered that a microphone in the CT room was out of order and that breath-holding instructions had not been given to the patient.
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Figure 7b. Artifacts due to incomplete breath holding. (a) Contiguous sections demonstrate almost no motion artifacts when each image is observed separately. (b, c) Coronal (b) and sagittal (c) reformatted images demonstrate banding artifacts with kymographic contours at the cardiac border. The patient had a heart rate of 58 bpm in normal sinus rhythm during scanning. Later, it was discovered that a microphone in the CT room was out of order and that breath-holding instructions had not been given to the patient.
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Figure 7c. Artifacts due to incomplete breath holding. (a) Contiguous sections demonstrate almost no motion artifacts when each image is observed separately. (b, c) Coronal (b) and sagittal (c) reformatted images demonstrate banding artifacts with kymographic contours at the cardiac border. The patient had a heart rate of 58 bpm in normal sinus rhythm during scanning. Later, it was discovered that a microphone in the CT room was out of order and that breath-holding instructions had not been given to the patient.
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Figure 8a. Partial volume averaging effect. (a) Right anterior oblique catheter angiogram of the left coronary artery shows no stenosis. (b, c) MPR images depict no significant stenosis but do show a small calcification, which appears larger than it proved to be in reality. (d) Virtual endoscopic image of the coronary arteries reveals a calcified deposit at the LAD artery (arrow) without luminal stenosis.
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Figure 8b. Partial volume averaging effect. (a) Right anterior oblique catheter angiogram of the left coronary artery shows no stenosis. (b, c) MPR images depict no significant stenosis but do show a small calcification, which appears larger than it proved to be in reality. (d) Virtual endoscopic image of the coronary arteries reveals a calcified deposit at the LAD artery (arrow) without luminal stenosis.
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Figure 8c. Partial volume averaging effect. (a) Right anterior oblique catheter angiogram of the left coronary artery shows no stenosis. (b, c) MPR images depict no significant stenosis but do show a small calcification, which appears larger than it proved to be in reality. (d) Virtual endoscopic image of the coronary arteries reveals a calcified deposit at the LAD artery (arrow) without luminal stenosis.
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Figure 8d. Partial volume averaging effect. (a) Right anterior oblique catheter angiogram of the left coronary artery shows no stenosis. (b, c) MPR images depict no significant stenosis but do show a small calcification, which appears larger than it proved to be in reality. (d) Virtual endoscopic image of the coronary arteries reveals a calcified deposit at the LAD artery (arrow) without luminal stenosis.
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Figure 9a. Partial volume averaging effect. (a, b) Coronary catheter angiograms show wall irregularity of the LAD artery (arrowheads) without significant stenosis. (c, d) On thin-slab MIP (c) and curved MPR (d) images, the patency of the vessel lumen in the coronary arteries is difficult to appreciate due to diffuse and dense calcification. This blooming effect can lead to the creation of nonassessable segments or to pseudostenosis, depending on interpretation.
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Figure 9b. Partial volume averaging effect. (a, b) Coronary catheter angiograms show wall irregularity of the LAD artery (arrowheads) without significant stenosis. (c, d) On thin-slab MIP (c) and curved MPR (d) images, the patency of the vessel lumen in the coronary arteries is difficult to appreciate due to diffuse and dense calcification. This blooming effect can lead to the creation of nonassessable segments or to pseudostenosis, depending on interpretation.
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Figure 9c. Partial volume averaging effect. (a, b) Coronary catheter angiograms show wall irregularity of the LAD artery (arrowheads) without significant stenosis. (c, d) On thin-slab MIP (c) and curved MPR (d) images, the patency of the vessel lumen in the coronary arteries is difficult to appreciate due to diffuse and dense calcification. This blooming effect can lead to the creation of nonassessable segments or to pseudostenosis, depending on interpretation.
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Figure 9d. Partial volume averaging effect. (a, b) Coronary catheter angiograms show wall irregularity of the LAD artery (arrowheads) without significant stenosis. (c, d) On thin-slab MIP (c) and curved MPR (d) images, the patency of the vessel lumen in the coronary arteries is difficult to appreciate due to diffuse and dense calcification. This blooming effect can lead to the creation of nonassessable segments or to pseudostenosis, depending on interpretation.
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Figure 10a. Streak artifacts. (a) On an image obtained after the administration of saline solution, no streak artifacts are observed around the RCA because attenuation of the right atrial appendage is lowered. (b) On an image obtained in a different patient without the administration of saline solution, streak artifacts produced by high-attenuation contrast material at the right atrial appendage (arrow) affect the visibility of the proximal RCA.
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Figure 10b. Streak artifacts. (a) On an image obtained after the administration of saline solution, no streak artifacts are observed around the RCA because attenuation of the right atrial appendage is lowered. (b) On an image obtained in a different patient without the administration of saline solution, streak artifacts produced by high-attenuation contrast material at the right atrial appendage (arrow) affect the visibility of the proximal RCA.
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Figure 11a. (a) Coronary catheter angiogram obtained after insertion of a Radius stent (SciMED Live Systems, Maple Grove, Minn) (arrowheads) depicts a patent RCA. (b, c) Curved planar reformatted images obtained in two perpendicular planes from CT data clearly demonstrate patency of the mid-RCA with coronary stent insertion. Note that almost no streak artifacts or blooming artifacts are observed.
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Figure 11b. (a) Coronary catheter angiogram obtained after insertion of a Radius stent (SciMED Live Systems, Maple Grove, Minn) (arrowheads) depicts a patent RCA. (b, c) Curved planar reformatted images obtained in two perpendicular planes from CT data clearly demonstrate patency of the mid-RCA with coronary stent insertion. Note that almost no streak artifacts or blooming artifacts are observed.
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Figure 11c. (a) Coronary catheter angiogram obtained after insertion of a Radius stent (SciMED Live Systems, Maple Grove, Minn) (arrowheads) depicts a patent RCA. (b, c) Curved planar reformatted images obtained in two perpendicular planes from CT data clearly demonstrate patency of the mid-RCA with coronary stent insertion. Note that almost no streak artifacts or blooming artifacts are observed.
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Figure 12a. Streak artifacts in a patient who had undergone stent placement 5 years earlier, although the kind of stent is unknown. (a, b) Thin-slab MIP (a) and MPR (b) images show apparent streak artifacts caused by a coronary stent in the left circumflex artery (arrows in a) despite the fact that almost no motion artifacts are seen. Streak artifacts due to very high attenuation contrast material completely obscure the intracoronary lumen. (c) Even on a CT scan obtained with a very wide window setting, only metallic structures can be recognized.
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Figure 12b. Streak artifacts in a patient who had undergone stent placement 5 years earlier, although the kind of stent is unknown. (a, b) Thin-slab MIP (a) and MPR (b) images show apparent streak artifacts caused by a coronary stent in the left circumflex artery (arrows in a) despite the fact that almost no motion artifacts are seen. Streak artifacts due to very high attenuation contrast material completely obscure the intracoronary lumen. (c) Even on a CT scan obtained with a very wide window setting, only metallic structures can be recognized.
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Figure 12c. Streak artifacts in a patient who had undergone stent placement 5 years earlier, although the kind of stent is unknown. (a, b) Thin-slab MIP (a) and MPR (b) images show apparent streak artifacts caused by a coronary stent in the left circumflex artery (arrows in a) despite the fact that almost no motion artifacts are seen. Streak artifacts due to very high attenuation contrast material completely obscure the intracoronary lumen. (c) Even on a CT scan obtained with a very wide window setting, only metallic structures can be recognized.
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Figure 13. Graph illustrates how inappropriate scan pitch and bradycardia create structural gaps (and, thus, artifacts) due to the shortage of data from the same cardiac cycle. Recon = reconstruction (reformation). At coronary artery imaging, data sets from the same cardiac cycle should be obtained from the entire heart.
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Figure 14a. Image blurring due to data shortage. A 60-year-old man underwent coronary CT angiography at standard pitch, during which his heart rate was 48 bpm. (a) Contiguous sections obtained at the level of the LAD and left circumflex arteries show blurring (arrowheads at left) in the left coronary artery as well as in the ascending aorta, pulmonary artery, right ventricle, and left atrium. Note that the images on the right show no motion artifacts. (b) Thin-slab MIP image shows pseudostenosis (arrow) and blurring (arrowheads) of the RCA. (c) Coronary catheter angiogram helps confirm the findings in b.
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Figure 14b. Image blurring due to data shortage. A 60-year-old man underwent coronary CT angiography at standard pitch, during which his heart rate was 48 bpm. (a) Contiguous sections obtained at the level of the LAD and left circumflex arteries show blurring (arrowheads at left) in the left coronary artery as well as in the ascending aorta, pulmonary artery, right ventricle, and left atrium. Note that the images on the right show no motion artifacts. (b) Thin-slab MIP image shows pseudostenosis (arrow) and blurring (arrowheads) of the RCA. (c) Coronary catheter angiogram helps confirm the findings in b.
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Figure 14c. Image blurring due to data shortage. A 60-year-old man underwent coronary CT angiography at standard pitch, during which his heart rate was 48 bpm. (a) Contiguous sections obtained at the level of the LAD and left circumflex arteries show blurring (arrowheads at left) in the left coronary artery as well as in the ascending aorta, pulmonary artery, right ventricle, and left atrium. Note that the images on the right show no motion artifacts. (b) Thin-slab MIP image shows pseudostenosis (arrow) and blurring (arrowheads) of the RCA. (c) Coronary catheter angiogram helps confirm the findings in b.
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Figure 15. VR images obtained with different window width and level settings show the LAD artery and a diagonal branch (arrow). Note that the change in the caliber of the diagonal branch is greater than that in the caliber of the LAD artery, indicating that smaller-caliber vessels tend to be more affected by the use of inappropriate settings.
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Figure 16a. Anatomic variant of the RCA in a 79-year-old woman who complained of chest pain. (a, b) Coronary CT angiograms clearly show the origin of the RCA from the left coronary sinus by simultaneously demonstrating the LAD artery and the RCA. (c, d) Images reveal that the RCA (arrows) is compressed between the ascending aorta and the right ventricle.
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Figure 16b. Anatomic variant of the RCA in a 79-year-old woman who complained of chest pain. (a, b) Coronary CT angiograms clearly show the origin of the RCA from the left coronary sinus by simultaneously demonstrating the LAD artery and the RCA. (c, d) Images reveal that the RCA (arrows) is compressed between the ascending aorta and the right ventricle.
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Figure 16c. Anatomic variant of the RCA in a 79-year-old woman who complained of chest pain. (a, b) Coronary CT angiograms clearly show the origin of the RCA from the left coronary sinus by simultaneously demonstrating the LAD artery and the RCA. (c, d) Images reveal that the RCA (arrows) is compressed between the ascending aorta and the right ventricle.
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Figure 16d. Anatomic variant of the RCA in a 79-year-old woman who complained of chest pain. (a, b) Coronary CT angiograms clearly show the origin of the RCA from the left coronary sinus by simultaneously demonstrating the LAD artery and the RCA. (c, d) Images reveal that the RCA (arrows) is compressed between the ascending aorta and the right ventricle.
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Figure 17. Proposed work flow chart for coronary CT angiography in terms of data creation, postprocessing, and image interpretation. It is essential to check for motion artifacts and consistency of data sets before proceeding to postprocessing, since a coronary artery segment imaged with motion artifacts or inconsistent data sets cannot be accurately diagnosed. The next step is to find high-attenuation areas for choosing the appropriate postprocessing methods. These steps allow reliable and effective interpretation of findings at coronary CT angiography.
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Copyright © 2005 by the Radiological Society of North America.
