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Right coronary artery ischemia

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History

An obese 55 year-old male presented with persistent chest pressure following a normal SPECT myocardial perfusion imaging study performed 1 month prior at an outside institution. He has a strong family history of early cardiac death and a personal history of hypertension and hyperlipidemia. He presents for evaluation with 82RbCl PET/CT.


Findings

Image 2: Wall motion at rest demonstrates normal findings with a LVEF of 73%. The cavity is normal in size.

Image 3: Wall motion images at stress demonstrate abnormal mild hypokinesis of the inferior wall motion and a stress LVEF of 70%.                                                                                                                                                                       Image 4: Coronary flow reserve information matches the abnormality seen on the perfusion images. The CFR value for the right coronary artery is 1.76, which is well below other regions.                                                                                                                                                                                                          Image 5: Coronary artery catheterization image demonstrating a 90% proximal RCA lesion (red arrow) and a right posterior descending artery lesion of 90% (yellow arrow).                                                                                                                                                                                                                         Image 6: Coronary artery catheterization image with additional view of the 90% proximal RCA lesion (red arrow).


Diagnosis

Right coronary artery ischemia


Discussion

Myocardial perfusion PET/CT is a technique which affords overall high sensitivity and accuracy for detecting coronary artery disease. The sensitivity for detecting single vessel disease is 92% and multivessel disease is 95% [1]. In the appropriate clinical setting, as with this patient, further evaluation of possible ischemia can be performed after SPECT MPI because of its higher sensitivity. It also allows for better imaging of patients who are obese, womeon with large breasts or breast augmentation and other situations where there can be increased attenuation on SPECT. In addition to these benefits, this technique also gives an overall lower radiation dose as compared with SPECT, providing that the attenuation correction CT dose is kept  low [1]. Quantitification of coronary flow reserve can also be performed with this technique. This allows the reader to assess the ability of the heart muscle to increase blood flow during stress. This quantification in the global sense has been found to be prognostic in some studies [2,3]. For this test, we see that there is regionally reduced flow reserve in the region of ischemia visualized on the stress images. This correlates well with the subsequent coronary angiogram images. 


Key points

PET myocardial perfusion imaging has higher overall accuracy compared to SPECT.  Quantification of coronary flow reserve can be used to assess at risk myocardium.



Author
Dr Erin Grady, MD, FACNM
Channel
ACNM Clinical cases channel
Right coronary artery ischemia Image 2

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Right coronary artery ischemia Image 3

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Right coronary artery ischemia Image 4

Image 4

Right coronary artery ischemia Image 5

Image 5

Right coronary artery ischemia Image 6

Image 6

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