DIP Episode 611 - Imaging and The USMLEs (Part 2)

All right, welcome to episode 611 of the Divine Intervention Podcast. In today's podcast, we're going to continue discussion on the image and the USMELIS. Image and the USMELIS. And honestly, in today's podcast, I'm going to focus on the nuclear medicine tests. Again, you may think that these topics are low yield, but by time I'm done with this podcast, you'll be like, oh, this stuff is actually pretty high yield to know for my exams. The thing is, there is a lot of nuclear medicine tests that are done in, honestly, in medicine. And there's a reason the USMELIS love to test them. And one thing I'm going to say is, you know, this is probably like, if you're a person that is very physiology inclined, if you're going into diagnostic radiology, this is probably going to be one of the most fun parts of diagnostic radiology you're going to see. And fact, actually, there's a specialty called nuclear medicine, like literally on its own, although it's rapidly dying. It's one of those disciplines that's pretty much common to the umbrella of just regular diagnostic radiology. All right. But many radiology residents hate this material because it's kind of hard. But honestly, it's really not hard if you just put in a little bit of work and effort to try to understand it. But again, we're going to focus on this from the USMELIS perspective, but I'll try to give you some bit of logic so that this stuff just kind of makes sense in your brain. All right.

So again, a lot of nuclear medicine tested on the USMELIS, right? So let's kind of start off with one that many of us are familiar with. That's the thyroid. Right. So what if they give you a question about like a 35-year-old man? And this man, you're told that for the last month, he's been having shortness or breath, having populations. They tell you that on physical exam, you notice that he has increased deep tendon reflexes has lead lag, right? With his eyes, lead lag. And then they tell you that which of the following is the most and you notice that the pressing has an irregularity of them on cardiac or scotation. And the pressing's heart rate is like 120 beats per minute, right? And then they say what's the most likely a theology of the patient's presentation? Well, I'll hope you're picking the answer that talks about a thyroid stimulating immune globulence, right? This person clearly has graves disease. Remember, graves disease is the most common cause of hyperthyroidism in the US, right? So whenever pressing has graves, the first thing you're going to hopefully check is the TSH, right? For many thyroid disorders, first thing you're going to check is TSH. And the TSH is going to be decreased in this person, right? Because you have these thyroid stimulating immune globulence that are literally stimulating the thyroid gland to make a lot of T3 and T4. If you make a lot of T3 and T4, that's going to suppress this is going to suppress TSH production, right?

So how do we diagnose graves disease? Well, one of the ways we diagnose it is to do a rio scan, a radioactive iodine-optic scan, right? A radioactive iodine-optic scan, you know, sometimes on the exams they'll call it thyroid's-integrity, thyroid's-integrity, right? So basically, we know that the thyroid gland takes up a lot of iodine. So the thing we're going to do is to basically give I-131, iodine-131, that's a radio nuclei, is going to be taken out by the thyroid, right? Now the thing is for USMD purposes, one of the better ways to learn this is to ask yourself, what causes increased optic with a rio scan and what causes decreased optic, right? So increased optic, and I'm going to provide like, hey, this is why you get increased optic and this is the reasoning. I think having that understanding of the reason will just make it make more sense to you and you can stick in your brain better, right? But like, for example, if a person has a toxic multi-nodular goiter, you're going to see increased optic, right? Because in a multi-nodular goiter, you have like an autonomous group of cells that are literally just making their own thyroid hormone, right? Same thing with toxic adenomins. You just have a bunch of cells making their own thyroid hormone. So since these cells are just on their own, of their own volition making a ton of thyroid hormone, that's going to cause them to take up this I-131. Because again, the thyroid loves to have it lead to take up I-131.

So you're going to see increased optic in a toxic adenoma in a multi-nodular goiter, right? And you're going to see that as well in gravestis, right? So if a person has gravestis, these thyroid stimulating immune globulins, they literally stimulate the TSH receptor. They're pretty much acting like TSH on the thyroid gland. So because you're having this continuous stimulation of the thyroid gland, the entire thyroid is going to light up, right? So make sure you can distinguish that from a toxic adenoma and a toxic multi-nodular goiter, where just subsections of the thyroid light up, right? The affected parts, increases the entire thyroid lights up, right? Now, typically on the USML Es, you're going to get a decreased optic on a riu scan when you have two things going on. Either you have your TSH suppressed or you have inflammation in the thyroid gland. Your TSH suppressed or you have inflammation in the thyroid gland. But that TSH suppressed situation is a big exception there is going to be grieves disease. It's going to be grieves disease. And again, I've explained to why, but I'm going to explain it again, right? But let's talk about the inflammation part, and then I'll talk about the TSH part. When you have inflammation, right? The thyroid gland is just heavily inflamed, heavily inflamed, heavily inflamed. Right? So like, for example, in the querving's thyroiditis, in those circumstances, in those circumstances, the thyroid is not going to be taken up iodine, right?

So you're not going to see any optic on a riu scan. So if your thyroid is going through an inflammatory cycle, it's not going to thick up radioactive iodine, right? So remember, decovines, right? Which we also call subacute thyroiditis, which also call granulomodostyroiditis. I remember, basically, the way that works is you have like a viral URI, and then a while after that, you have like very painful thyroid. And usually they're going to start off with thyroid toxic symptoms, right? Because all that inflammation is going to lead to the release of preform thyroid hormone. And then over time, they will recover, right? So because of that inflammation, right? The thyroid cannot thick up iodine, you're going to have decreased optic on a riu scan, right? But I also said that, man, if you have decreased TSH, you also have decreased optic on a riu scan, right? Because think about it. If you have low TSH, then your thyroid gland is not being stimulated. Remember, TSH literally stimulates the thyroid gland to take up iodine for the production of thyroid hormone. So if your TSH is low for any reason, then your thyroid gland will not be stimulated to make to take up that iodine to make thyroid hormone, right? So say, for example, you're using thyroid hormone exogenously, you know, like fictitious hyperthyroidism, then you're not going to have any good optic on a riu scan, right? Because you're taking thyroid hormone exogenously, that's going to suppress your TSH.

So your thyroid gland is not being stimulated. Since it's not being stimulated, you're going to have a decreased optic, right? Or let's say a person has like a teratoma that is making thyroid hormone, right? Like stromal varii. Now, basically, a stromal varii, right? Your thyroid gland, you know, you have this teratoma making a ton of thyroid hormone. Your T34 is high. Your TSH is going to be suppressed. So your actual thyroid gland will not be stimulated. That's going to cause decreased optic. But I said that all that gravestisiesis and exception where your TSH should be low, but you actually have increased optic on a radioactive iodine optic scan. The reason in there is that the thyroid stimulating immune globulins that we see in griffes disease they pretty much work like TSH receptor agonists. It's not they're pretty much. They're essentially TSH receptor agonists. So they are pretty much working like TSH, right? That's what's stimulating the thyroid to make tons of T3 and T4. And then that's what presses TSH production, all right? So again, that's why the TSH may be low, but you have increased optic on a riu scan, right? And the thing is there are a few quirks with the I-131 business that they love to test on the exams, right? First things first again, make sure you can identify these different riu scan findings like, hey, what does griffes disease look like? What does a multi-nodalagoidal look like? Where you're going to see many spots of increased optic?

What does a toxic adenoma look like? You're not going to see one focus of increased optic, right? And don't forget that you can also do what I want 31 for like ablation, you know, you can use that for griffes disease. That's actually how we treat griffes disease or toxic multi-nodalagoidal. Just give I-131 to update the thyroid gland, right? Because those riu also tell us they make radiation that can destroy the thyroid, right? So you give I-131, obviously a bigger dose than the imaging dose, right? And that will update the pressing thyroid in griffes or toxic multi-nodalagoidal. And then I guess I just want to discuss this as a side point, actually two side points, right? First things first, they can give you a question about griffes disease in a pregnant woman and ask you how you should treat it. I'm really hope that you're not picking the answer that involves giving I-131 in pregnancy, please. Do not give I-131 in pregnancy. It is very dangerous, right? It's going to deliver radiation to mom and the baby and that's not good, right? And also they can actually give you a preventive medicine question. After a pressing gets I-131 radioablation, if you get I-131 radioablation, you need to basically stay away from people for a while. You need to stay away from people for a while because basically that I-131 that's in your thyroid, you are just rediting it out to other people, right? So you just kind of want to be careful about that, right?

And one of the side points, I don't know why this is just kind of in my heart to talk about. But it's actually pretty high yield to know for you exams. If for example a person has, you get a scenario in your test and a person has got in I-131 radioablation. And then down the line, you're trying to check for recurrence. So you know, let's say they got the I-131 ablation for something, right? Let's say for like thyroid cancer or whatever, right? How can you check for recurrence of the thyroid cancer? Well, I really hope you're saying, ooh, divine, I'm gonna check the thyroid globulin levels. Because remember, thyroid globulin is like the CPAP type of the thyroid gland. So if you have functioning thyroid tissue that has come back, you know, like cancer that has come back or recurrence of like thyroid disease, you'll be making a lot of T3, T4, you'll also be making a lot of thyroid globulin. So your thyroid globulin may be elevated, right? So checking thyroid globulin levels is actually a pretty great way to assess a person for like recurrence of thyroid cancer, right? So just something you want to keep at the back of your mind for, for example. All right. Now the next thing we're gonna talk about, right? What if they give you a question about a person that is pregnant and over the last three hours, she has been having like significant shortness of breath? And you're told that, you know, you get an EKG and you notice that the EKG is completely normal.

But the person's heart rate is pretty high, right? This person probably has a PE, right? You're probably seeing the sinus tachycardia on an EKG, right? So typically what kind of imaging tests do we like to use for P Es on the USML Es? Well, I'd really hope you're saying that, especially for P Es in pregnant women, I want you to think of a VQ scan, a ventilation profusion scan, right? So who are the people that get these VQ scans? Number one, it's gonna be people that are pregnant that have a PE, right? They suspect the PE in. And other group of people that you do this with are people that have like allergies to iodinated contrast, because remember the contrast that we use for, you know, CT, chest, and diagrams, the mid of iodine. If you have allergies to that, then obviously you can do that other study, you need to do a VQ scan instead. Or let's say for whatever reason, you have renal failure, right? Because remember, I do need a contrast can torture your kidneys. If you have renal failure, then in that case, a VQ scan will be indicated if you're trying to rule out a PE, right? So a VQ scan, basically, what you do is that you, there are actually two phases to the study. There's a reason it's called a VQ scan, right? It assesses ventilation, that's the V, and profusion, that's the Q, right? Q is a just general term in physiology for profusions, right? So the thing that happens is first, you inhale a radioisotope, right?

You inhale the radioisotope, and then we take scans of your lungs, right? We take scans of your lungs. So we assess the ventilation, right? Because you're just inhaling that stuff. And then after that, we give you a tracer, that's injected intravenously, right? And that tracer, just because of its size and stuff, it gets trapped in the pulmonary, like your pulmonary capillaries, right? So that gives us an idea of, hey, how well is blood flowing in your lungs? How well are your lungs being profused, right? So let's look at the normal situation. The normal situation is that what you see from the scans, the radioisotope scans with ventilation should roughly match what you see with that radioisotope that you injected with profusion. There should be a match, right? Ventilation and profusion in the lungs tend to match, generally. And you can see this beautifully on the image. I've actually seen a lot of these kinds of images, right? So the V scan should match the Q scan, right? So the thing is, P is something I'm gonna worry about. When the V scan does not match the Q scan. So you see good ventilation with the V, the ventilation scan. But you notice that man, there are these like defects, like these areas that did not take up the tracer. When you do the scan, after you've injected that radioisotope intravenously, the Q part of the scan, right? So you're gonna see things like wet-shaped infarcts, for example. If you see that, right, think of a PE, right?

You'll be, you know, basically you're getting good ventilation for your simple profusion. That tells you that, oh, this person probably has a PE, right? This person probably has a PE. Because remember, a PE is a profusion issue, right? In fact, sometimes our friends at the MBM is, instead of using the term Pomonairem bolos, they can just use the term Pomonaire profusion defect. Pomonaire profusion defect to talk about a Pomonairem bolos on your exams, right? So again, when do we use VQ scans, Rural L Ps and pregnant women, people that have like really bad allergies to either the needed contrast or people that have renal failure, right? And the thing is, VQ scans tend to report results in probabilities. When a VQ scan tells you that you have a high probability for a PE, then yeah, we're pretty worried that person has a PE, right? Most of the other probabilities are not as useful, right? But if he says high probability for a PE, yeah, you definitely probably have some kind of PE. All right, now let's look at, what if they give you a question about a person? And they tell you that this is a 55 year old male, you know, the has chest pain that is kind of worsened by activity, right? Kind of worsened by activity. You know, but when he rests for a few minutes, he feels better, right? So this person has angina, right? Probably has stable angina, right? Typically when people have angina, it's usually reasonable to do some kind of stress test, right? To do some kind of stress test.

Now remember, stress tests involve two things, right? There is a method of stress in the heart, you know, either like exercise or do you the mean or a denocene or diperidomal or, you know, whatever. And then there is a method of assessing the cardiac response to that stress, right? You can do an EKG, right? To assess the heart response to the stress, you can do an echo cardiogram or you can do these a nuclear medicine test. So let's focus on the nuclear medicine tests. The nuclear medicine tests, they usually use things like magnesium, 99 M or phallium 2001, magnesium 99 M or phallium 2001, right? So use these for cardiac scanning as a part of a stress test, right? To assess the cardiac response to that stress. So the thing is, technician 99 M, we kind of prefer that to phallium because phallium 2001 delivers like just tons and tons and tons of radiation, right? And the thing is, you may wonder like, man, define, like these tests are like a black box in my brain. Why do we even do that? Let me give you like a little bit of context. I'm not gonna go into detail on this, like honestly, this can easily be like a one plus our lecture just on this stuff, right? But just to give you a little bit of context, right? We use these tests to determine if we're dealing with ischemia of the heart or we're just dealing with straight up infarction of the heart, right? We're dealing with ischemia infarction, right?

Because the thing is, when you inject these radio tracers, you then try to look at the flow, you know, like in your coronary vessels and your myocardium, right? Amongst your myocardium and stuff, right? So we're looking for flow defects basically. And we're doing this at rest and at stress, right? So typically we're gonna take images, and we're gonna give, you know, we're gonna take images at rest and at stress, right? So say for example, if you see flow defects, at rest and during stress, at rest and during stress, then that tells you that, oh, this is probably an infarcted myocardial tissue because it's like at rest, you're not seeing any flow. During stress, you're not seeing any flow. You're getting the same results at rest and stress. This is myocardial tissue that is infarcted, that is probably scar tissue, right? That tissue is no longer viable. It's not re-vascularizable. But if you see flow defects only during stress, well you notice that, oh, those flow defects are not present at rest. So when you're resting at your heart is not working as hard. You notice that there is no flow defect. But when you're stressed, right? When you're running on a treadmill or your heart is being stressed pharmacologically, you notice that there's a flow defect. That tells us that there is some kind of ischemia going on, right? Some kind of ischemia going on, right? So that tells you that, oh, okay, so at rest, profusion is good. What at during stress, profusion is bad.

This heart is at risk. This myocardial is at risk, right? That's a good candidate for re-vascularization. That tells you that, oh, you're dealing more with ischemia than infarction, right? Then you're dealing more with ischemia than infarction, right? So again, trust me, there is way more permutations than there's like viable, non-viable, blah, blah, blah. Right? But again, that's more for ideology residents who are nuclear medicine residency. I'm not gonna go into those details at all in this podcast. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. I'm not gonna go into those details. Right? So I'm gonna keep at the back of your mind for, for example. Right. Now, the next one I wanna talk about, right? So what if they give you a question about a patient? And this patient presents with like significant right upper quadrant pain and fever. Right? But the patient has like no jaundice, but they have luchositis and things like that. Right? Clearly this person has like cutelessly stitis.

And we know that when a person has like cutelessly stitis, the first thing you're gonna do is a right upper quadrant ultrasound. Right? But what if that right upper quadrant ultrasound is unremarkable? It's negative. Are you done ruling out a cutelessly stitis? Well, the answer to that is gonna be no. Right? In that case, what kind of scan are you gonna do? Well, you're gonna do a hyda scan, a hyda scan. Right? Remember, another name for a hyda scan on the USML Es is hepato biliore scintigraphy. Hepato biliore scintigraphy. Right? Hepato biliore scintigraphy. Right? Again, the typical use on your exams is when a person has, when you suspect that cutelessly stitis, and the right upper quadrant ultrasound is negative. Right upper quadrant ultrasound is negative. So, how does this test even work? Again, let me give you a little bit of context. If notice, my context, I'm not spending too much time on that. But let me give you a little bit of context. So, you pretty much inject the tracer intravenously. Right? And this tracer is conjugated to a protein that is taking up very heavily by your hepato sites, by your liver cells. So, the thing is, after it's taken up by hepato sites, well, we know that stuff that's taken up by hepato sites, they're gonna excrete it into a bile. Right? And bile is gonna be excreted into like the gallbladder, for example. Right? And into the biliary tree. So, you know, so this test takes a while. Right?

So, you notice that, oh, you wait like an hour or whatever. Right? So, you would hope at that point that, hey, by that time, your hepato sites have excreted this thing in two-byel. Right? So, what's gonna be the normal situation? Well, the normal situation is that this radio tracer should be taken up by the gallbladder, because when the hepato sites excrete it into the biliary ducts, it then goes into the cystic duct, and then goes into the gallbladder. So, after like an hour or so, you should be able to visualize the gallbladder pretty well with a high-dascant, because that tracer has gone through that patent cystic duct and entered into the gallbladder. Right? Entered into the gallbladder. So, if you notice, however, that's wait. I can't visualize the gallbladder like a few hours after I've injected this tracer, you know, with like the specialized nuclear imaging. Then that tells you that the cystic duct must not be patent. It means the cystic duct must be obstructed. It means that, ooh, the cystic duct is obstructed, so that's why I cannot see the gallbladder. Right? It pretty much means that the patient has a cure-cullisistitis. Right? It means the patient has a cure-cullisistitis. Right?

So, again, on your exams, if they tell you that, and they can literally use this terminology, they say that, ooh, a high-dascant or hepato-biliris integrity feels to disclose optic in the gallbladder, or they tell you that the gallbladder is not visualizable, like a few hours after you give that tracer, you know, like one hour or more after you give that tracer. Then that tells us that, ooh, this pressing probably has a cure-cullisistitis. Right? Now, what are some other uses of the high-dascant emission you exams? High-dascant is used to detect like biolics, you know, post-operatively, right? You know, see, for example, you have gallbladder surgery. Sometimes you can have a biolic, right? You can see that if you inject that tracer, right? That, again, kind of floats around in biol. If there's a biolic, you'll see that tracer going beyond the confines, beyond the boundaries of your biliric tree. All right. And then, as I wrap up, let me just maybe talk about a few more quick tests here and there, right? So don't forget the Mechel scan, right? Is the Technician 99 M scan, used for Mechels, that I've particular on, right? Remember Mechels is going to be a young boy, you know, that for, you know, has been having just these painless, bloody stools and things like that, right? Another one you miss your exams is a Somatos-statinsentigraphy. Somatos-statinsentigraphy. This one is very, very good for neuroendocrine tumors, right?

Especially like gastrinomas and carcinoid tumors, right? Somatos-statinsentigraphy is amazing, amazing, amazing for those kinds of tumors, right? Another one you miss your exams is an M-I-B-G scan, right? An M-I-B-G scan. We tend to use this for things like fiochromositomas or for, like, neuroblastomas. You can also occasionally use them for medallary thyroid cancer. But typically, on the exams, fields and neuroblastomas, especially when you're trying to look for, like, distant metastasis, right? Or let's say you do, like, a CT on MRI of the abdomen, and you can find the field. And M-I-B-G scan is going to be very helpful. And maybe one train divine. Why does the M-I-B-G scan help? Well, the thing is M-I-B-G is a neuropinephrine analog. It's literally a non-epinephrine analog, right? So we know that, you know, fiochromositomas, neuroblastomas, these things may produce caracolamines, right? They may make and produce caracolamines, right? So you notice that, ooh, on M-I-B-G scan, you're seeing a lot of optic, a lot of optic, right? Many of these nucleomedicine tests were just looking for optic, optic, optic, right? And then don't forget, if, for example, they give you a question about a person that has, like, you know, like, they feel dizzy, they have abdominal pain, you know, like 20 to 30 minutes after they eat a meal, and they tell you that this person recently had gastric bypass. You want to think of a person that has dumping syndrome.

You want to think of a person that has dumping syndrome, right? That dumping syndrome is associated with rapid gastric emptying. One of the ways we can test your gastric emptying is by doing something called literally a gastric emptying study. Sometimes on the US Emily exams, they call this gastric sinthigraphy, gastric sinthigraphy, gastric sinthigraphy, gastric sinthigraphy, right? It's basically a kind of emptying study. To see how rapidly, so there are normals for how quickly your bowel should, you know, your bowel should not empty, you know, your stomach should empty, but, you know, there's, when it goes beyond those boundaries, right? It tells you that it's either slow gastric emptying, which you may see in certain disorders like diabetic gastroparesis, or you may see rapid gastric emptying in situations like a dumping syndrome, for example, right? And then the next test I want to talk about, right? So what if a person, for example, has been treated for H. Pylori, and you want to do a test of cure, right? A test of cure for H. Pylori, right? Remember, if you want to do a test of cure, you don't want to do an antibody-based test against H. Pylori, because those antibodies, once positive, they'll always be positive, so they cannot really help you differentiate between a primary infection, and oh, wow, you've been cured or whatever, right? So it's not very helpful. You can use them to initially try to diagnose H.

Pylori, but once those antibodies are positive, they'll always be positive. You cannot use them as a test of cure, right? One common test of cure are friends that the NBM is love to use. It's something called the urea-breath test, the urea-breath test, right? You use it to make, you know, either a diagnosis of H. Pylori, but you can also use it to confirm that the presence H. Pylori has been eradicated, right? So how does this test work? Again, let me give you some context, right? Basically, the thing that happens is that you get carbon-14, a radio-liboled urea, right? Carbon-14 is a radioisotope of carbon. I'm probably remember that from organic chemistry, but we're going to go into chemistry here. Can you guys tell that I really love chemistry, but we're not going to go into chemistry here, right? So you give radio-liboled carbon-14, and then, so radio-liboled urea that contains carbon-14, right? And then, you know, the H. Pylori in your GI tract is literally going to, because it's urea-is-positive, it's going to break down that radio, you know, 14 carbon-14 radio-liboled urea. It's going to break it up into carbon dioxide and ammonia, right? And then that carbon dioxide is detected in your breath, right? If you detect that carbon dioxide in the presence breath, it tells you that, ooh, there must be some kind of urea-is-positive organism in the presence of GI tract. And who's going to be the big culprit most of the time? It's going to be what? It's going to be H. Pylori.

So H. Pylori. So you can use the urea-breath test to either diagnose H. Pylori. And you can also use it as a test of cure. All right. And then, you know, don't forget your bone scans, right? Don't forget your bone scans, you know, sometimes on the example, they call it bone-syntigraphy. You pretty much give like a tracer. I'm not going to talk about a tracer, but it's like a derivative of technician 99 M. That tracer binds to the hydroxyapatite in bone, right? It binds to the hydroxyapatite in bone, right? Usually we're going to use a bone scan for Paget's disease, for Paget's disease of the bone. Now, one thing I want to say here is that you can also use a bone scan for bone mites of cancer, especially if a person has plastic lesions, plastic lesions. Generally, when you have lady collisions of the bone, you're not going to get very great optic, right, with a bone scan, right? So, you know, lady collisions, like, for example, like if a person has multiple myeloma, it makes very limited sense to do a bone scan, because multiple myeloma is going to cause a lady collision, right? That doesn't really make sense in that circumstance. All right. So I think we're going to go ahead and stop here. Again, I think I've kind of talked about a lot of stuff here, but again, please, this podcast is pretty high-yielding, honestly. If you understand these mechanics behind these different tests, you notice that these things actually pretty easy.

You don't have to, like, endlessly memorize, memorize, memorize, memorize, memorize. So thank you for listening to me today. I will see you in episode 612. Again, there's still more meat on this imaging bone. To be honest with you, I'm just basically, I made up my mind that, hey, imaging is a hard concept for many people on the USML Es. So let me just make a series that thoroughly addresses it. If you listen to this series, I don't see why you should struggle with much of any much in the way of imaging questions on your exams. And then, if you're interested in my classes, if you love the way I teach, I do offer many classes for step 1 to 3, level 1 to 3. Like, today this evening, I do have a five-hour social sciences, quality improvement, ethics, and hospital medicine class. It's for step 1 to 3. Many people have taken this class and found it to be exceedingly helpful for their exams. And then, tomorrow for step 2 and 3, specifically, I have a three-hour last mini review, like a last mini primer for step 2 and 3. And then, next week, from Monday to Friday, four hours every day, so 20 hours total, I have a 20-hour class for step 2, seeking step 3. Again, many people have taken these classes and found it to be helpful. I've literally had people take the classes as recently as within the last few weeks and get like in the high 270s on their exams. Again, I tell you, these classes are well put together. They're pretty thorough. Many people find them to be exceedingly helpful.

So take these classes, they're really going to help you in preparing for your exams. And then, I also have a test taking class and a bio stats class. I'm going to be offering those the first two days of next month. Alright, and then I have this podcast on Apple Google on Spotify, so please check those out. I also have a You Tube channel you can check out. That's where I post the videos that I make. And then, remember, I also offer one or one tutoring for all the US Milion Complex exams. And I also help with like, era's applications, personal statements, mock interviews, and things of that nature. And then, I have another website titled, Divine Intervention Lifelessens.com. Basically, every week, many of you know I'm a Christian, every week I post like two to three podcasts from a biblical perspective, address a life lesson. Many people have actually listened to these podcasts and found them to be really helpful. There's actually an Apple podcast associated with this called, the Divine Intervention Life Lessons podcast, Divine Intervention Life Lessons podcast. Alright, it's an Apple podcast. So, thank you for listening to me today. I will see you God willing episode 612. Have a wonderful day. God bless you and the wife right now. Thank you.

Low TSH + Diffuse, high uptake throughout the entire thyroid gland.

Pregnancy, severe contrast allergy to iodine, or renal failure (contraindications to CTPA).

Obstruction of the cystic duct, suggesting cholecystitis.

Urea breath test (detects $\text{CO}_2$ from urea breakdown).

Ischemia (viable tissue at risk), indicating potential for revascularization.

Technetium-99m ($\text{Tc}-99\text{m}$).

Low TSH and increased, diffuse uptake.

Increased uptake localized to multiple distinct nodules/areas.

Suspected acute cholecystitis when RUQ ultrasound is negative.

V/Q scan (Ventilation/Perfusion).

$\text{CO}_2$ in expired breath resulting from urease activity.

Thyroid cancer (since TSH-independent functioning tissue is present).

Low TSH and increased, diffuse uptake.

Increased uptake localized to multiple distinct nodules/areas.

Suspected acute cholecystitis when RUQ ultrasound is negative.

V/Q scan (Ventilation/Perfusion).

$\text{CO}_2$ in expired breath resulting from urease activity.

Thyroid cancer (since TSH-independent functioning tissue is present).