Welcome everyone, I'm Azimullah Akram, Houston Methodist, and I'm tasked to talk to you now about the exam interpretation and case-based review. So when we're looking at a PET exam, first, these are my disclosures. All right, so when we're looking at a PET exam, the focus is primarily to identify first of all the quality. So we want to make sure that we have a good quality exam. We want to look at the images, and we have multiple images that we can obtain from PET. So we look at the static images to identify perfusion defects. We look at the gated images to look at LV function and regional one motion abnormalities. We also look at CT images to look for coronary calcifications. And finally, we look at the dynamic images to get the blood flow data. So I will demonstrate that in a couple of cases over the coming few minutes and try to highlight the importance of looking at all this data. So the first case is a seven-year-old male who presented with chest pain, and this patient had multiple comorbidities or risk factors, including hypertension, dyslipidemia, and diabetes. He was obese. His BMI is 37 kilograms per meter square. The patient underwent a pharmacologic stress with vasodilator stress using rigadenosone. The tracer we use in this exam is this new tracer that was just approved by the FDA, which is called F18 floperidaz. And we use a low-dose at rest and then high-dose stress protocol. The patient tolerated the test very well. He did not have any chest pain or shortness of breath during the test, and he had no EKG changes on the EKG tracings. These are his quality images that first we look at because we are using a PET CT in this patient. So we want to look for multiple quality measures. One of them is looking for registration and making sure that the myocardium is not overlaid by any of the lung tissue. So what I usually say is, well, the heart is where it should be, and it is well placed in there. And this looks like a good quality study. There is no overlaying of the lung by the heart tissue or vice versa. So when we look at the images, we're going to start with, we have multiple displays of the coronary of the myocardium. On top, you see the stress images. The second row are the rest images. And then we display them in multiple ways. The first one is a short axis, that's the first four rows. And this will be anterior wall, septum, lateral wall, and inferior wall. And then we also present them in the horizontal long axis where we have the septum and the lateral wall here. And then we also display them in the vertical long axis where we have the anterior wall and the inferior wall mostly displayed. Now we go from septal to lateral wall. So we look for the homogeneity of the uptake, and you can see at rest there was homogeneous uptake all through. But on stress, which is on the top row, you can see that there is a perfusion defect. It is large because it's more than five segments, and out of the 17 segments, and it is moderate. It's actually severe in the inferior, infralateral, and infrared septal segments, basal, and also the middes involved and the apical. So it's a large perfusion defect. We also noted on this patient the normal apical thinning artifact that we see with path myocardial perfusion imaging more pronounced because of the better resolution. So you can see here another display with the polar maps to kind of give us a good example about the defect there. And we also can get the gating, and you will see here with using a different color display or black and white, we look at the gating and we see some hypokinesis in the inferior wall compared to rest imaging where the inferior wall is contracting. So there is a perfusion defect in the inferior wall, inferior, infrared septal, and infralateral. There is wall motion abnormality already. When we look at the CT images, there are extensive coronary calcifications noted in the LAD in the left circumflex. I'm only showing you a quick snapshot of that, and we also see extensive coronary calcifications in the RCA. So there are severe three-vessel coronary calcifications that we see here. And when we look at blood flow, so we are able to quantify blood flow, and you can see nearly homogeneous blood flow at rest. But now at peak stress, we see that the inferior wall has reduced hyperemic myocardial blood flow there compared, for example, to the anterior wall, septal, and anterolateral segments. And the flow reserve, although globally normal, it is significantly reduced in these segments compared to what we see in the other territories, further confirming our abnormalities that we see here, but also telling us that there is probably, although there are a ton of calcifications in the other segment, there's probably no hemodynamically significant disease in the LAD and left circumflex. Our final impression that there is large area of severe ischemia in the RCA territory, and there are severe coronary calcifications in this patient, and this patient went ahead for angiography, and he has a large RCA, which has 99% stenosis. He had moderate lesions, but not flow-limiting in the distal LAD and the mid-circumflex, despite the heavy coronary calcifications that we see here. And the last few minutes, I want to show you another quicker case. This is a 59-year-old male who came in with chest pain. The patient had history of dyslipidemia and overweight and mild obesity there with a BMI of 32. The patient underwent exercise using Bruce protocol. We were able to do exercise because we used the FAT-inflapillidase tracer, which is a new venue or new opportunity to do exercise, but that was not possible with prior tracers. We also used a low-dose rest, high-dose stress, no chest pain during stress, and again, negative EKG response. When we look at quality here, I'm showing it to you in different display, but we also confirmed that there are no misregistrations, maybe a tiny bit, a small segment there, but no significant misregistration that we see. So from a quality standpoint, this is a good study, and we're happy with the quality that we see. And again, when we are looking at the perfusion, you can see the images, homogeneous uptake at rest. So this row here, I see homogeneous uptake continues on this row. Same thing at the rest images, and same thing applies to the vertical long axis. But that stress, we're also seeing a defect smaller than the prior patient, but also involving the inferior infraroceptal wall, and this was quantified to be around 9% of the entire LV. So it's a small to moderate-sized defect, and you can see here, we can quantify it. It's involving like two to three segments in there, and when we look at gated, we see some hypokinesis in the area of the perfusion defect, and we could not obviously quantify blood flow, because this was an exercise test, and this is one of the areas that there is research going on to quantify that. We see some calcifications in this case on the attenuation scan, but not as significant as a prior case. And in this patient, the conclusion is that there is moderate area of severe ischemia in the RCA territory. There are moderate coronary calcifications, and this patient was referred for coronary angiography, and we found out that the patient had a mid-RCA, which was 100%, and mid-LAD, 40%, and proximal circumflex was 15%. So I hope these two cases showed you how we can able, how we systematically evaluate and interpret cardiac path cases, and one was with pharmacologic stress, and the other one was with exercise using floperidaz as a radiotracer. Thank you very much for listening.

PET scans

imaging techniques

perfusion defects

coronary calcifications

F18 floperidaz