Latest / Heart Health, Reimagined with Dr. Mona Shah, MD / Coronary Calcium, CIMT, or CTA - Which Test Actually Answers Your Question?

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Coronary Calcium, CIMT, or CTA - Which Test Actually Answers Your Question? · Heart Health, Reimagined with Dr. Mona Shah, MD

• 0:00
  SPEAKER_00: I get asked this question all the time.
• 0:03
  SPEAKER_00: Should I get a calcium score?
• 0:04
  SPEAKER_00: Should I get a carotid ultrasound or CIMT?
• 0:09
  SPEAKER_00: Or should I get a coronary CT angiogram?
• 0:12
  SPEAKER_00: Before we go any further, what is CIMT?
• 0:16
  SPEAKER_00: CIMT stands for carotid intima media thickness.
• 0:20
  SPEAKER_00: It's an ultrasound measurement of the thickness of the inner layers of the carotid artery wall, the arteries in your neck that carry blood to your brain.
• 0:29
  SPEAKER_00: That's different from a regular carotid ultrasound that looks for actual plaque or narrowing in those arteries.
• 0:37
  SPEAKER_00: So already we're talking about very different things.
• 0:40
  SPEAKER_00: A calcium score looks for calcified plaque in the heart arteries.
• 0:45
  SPEAKER_00: CIMT measures carotid artery wall thickness.
• 0:50
  SPEAKER_00: A carotid ultrasound can look for actual plaque in the neck arteries.
• 0:55
  SPEAKER_00: And a coronary CT angiogram lets us look directly at the heart arteries and see both calcified hard plaque and non-calcified soft plaque.
• 1:06
  SPEAKER_00: And then I hear, but plaque is plaque.
• 1:08
  SPEAKER_00: If you find plaque in my carotid artery, aren't you going to treat me anyways?
• 1:12
  SPEAKER_00: Yes, if I actually find carotid plaque, I absolutely care.
• 1:17
  SPEAKER_00: Atherosclerosis simply means plaque buildup in the arteries.
• 1:21
  SPEAKER_00: And if it's in your carotid artery, I know it's already present.
• 1:25
  SPEAKER_00: But I also want to know what's happening in your heart arteries because I want to understand both your stroke risk and your heart attack risk.
• 1:34
  SPEAKER_00: And those two don't always match.
• 1:37
  SPEAKER_00: Here's a part people often miss: the reverse doesn't work.
• 1:41
  SPEAKER_00: If your carotid arteries are clean, that does not prove your heart arteries are clean.
• 1:47
  SPEAKER_00: And if your calcium score is zero, that doesn't completely prove it either.
• 1:53
  SPEAKER_00: Up to about one in six people with no symptoms of heart disease and a calcium score of zero still turn out to have soft non-calcified plaque hiding in their coronary arteries that they didn't even know was there.
• 2:09
  SPEAKER_00: So these tests are not interchangeable.
• 2:12
  SPEAKER_00: By the end of this video, I want you to really understand exactly what each test can tell you, what it can miss, and what questions you should take to your doctor.
• 2:21
  SPEAKER_00: I'm Dr.
• 2:22
  SPEAKER_00: Mona Shaw, cardiologist, board certified in cardiology, holistic medicine, and cardiac CT.
• 2:29
  SPEAKER_00: I actually read coronary CT angiograms myself.
• 2:32
  SPEAKER_00: If you've watched this channel, you know my approach to prevention isn't just do you have a huge blockage?
• 2:40
  SPEAKER_00: I want to know if atherosclerosis or plaque buildup is already there.
• 2:45
  SPEAKER_00: Because for many people, the first time they find out they even have coronary disease is when something happens.
• 2:53
  SPEAKER_00: And many heart attacks arise from plaque that wasn't causing a severe blockage beforehand.
• 3:00
  SPEAKER_00: So prevention can't only be about finding an 80 or 90% narrowing.
• 3:05
  SPEAKER_00: I want to identify disease earlier while we still have the opportunity to change the trajectory.
• 3:12
  SPEAKER_00: I already have full videos on coronary calcium scoring called the 10-second heart scan that detect heart disease early, and I have one on coronary CT angiograms, the scan that shows all plaque, where I go deeper into why non-calcified soft plaque matters.
• 3:28
  SPEAKER_00: I'll link them below in the comments.
• 3:30
  SPEAKER_00: So today I'm not reteaching either tests.
• 3:33
  SPEAKER_00: Today we're comparing them.
• 3:36
  SPEAKER_00: So let's start with CIMT, probably the least understood of the three.
• 3:41
  SPEAKER_00: Again, CIMT means carotid intima media thickness.
• 3:47
  SPEAKER_00: It's measured by ultrasound, and it measures the combined thickness of the inner layers of the carotid artery wall.
• 3:55
  SPEAKER_00: Historically, CIMT was used as a marker of cardiovascular risk.
• 4:01
  SPEAKER_00: But here's an important distinction.
• 4:03
  SPEAKER_00: CIMT is not the same thing as finding actual carotid plaque.
• 4:08
  SPEAKER_00: Wall thickness can be influenced by aging, high blood pressure, and other changes.
• 4:13
  SPEAKER_00: Actual plaque means atherosclerosis is present.
• 4:17
  SPEAKER_00: And when researchers have compared these tests, CIMT simply hasn't performed as well as coronary calcium for predicting coronary events.
• 4:28
  SPEAKER_00: That's a well-established finding from research using the Mesa cohort, one of the largest studies on this question.
• 4:36
  SPEAKER_00: This is one of the major reasons cardiovascular guidelines no longer recommend routine CIMT measurement as a standard way of assessing heart attack risk.
• 4:48
  SPEAKER_00: Now that doesn't mean carotid ultrasound is useless.
• 4:52
  SPEAKER_00: If you have actual carotid plaque, that's very important to me.
• 4:56
  SPEAKER_00: It tells me that you already have athosclerosis building up in your carotid arteries.
• 5:01
  SPEAKER_00: And it makes me more interested, not less, in what your coronary arteries look like.
• 5:06
  SPEAKER_00: But if your carotids are completely clean, I cannot say there's therefore no plaque in your heart arteries.
• 5:15
  SPEAKER_00: That test simply can't answer that question.
• 5:19
  SPEAKER_00: One practical note: not every center performing a standard carotid ultrasound actually measures CIMT.
• 5:27
  SPEAKER_00: A regular carotid study may evaluate plaque and narrowing without a standardized CIMT measurement.
• 5:34
  SPEAKER_00: So if you're considering it, ask specifically whether they're measuring CIMT or doing a standard carotid ultrasound looking for plaque.
• 5:43
  SPEAKER_00: And if actual carotid plaque is found, that's where it becomes much more meaningful to me.
• 5:49
  SPEAKER_00: Because your carotid arteries tell me about stroke risk and your coronary arteries tell me about heart attack risk.
• 5:55
  SPEAKER_00: And those two vascular territories don't always match up.
• 5:59
  SPEAKER_00: So again, if I find carotid plaque, I very much want to know whether there's coronary plaque as well.
• 6:06
  SPEAKER_00: This is exactly why I created this channel.
• 6:09
  SPEAKER_00: Not because I want you to order every available heart test and to be clear, most people don't need a coronary CT angiogram, but so you understand enough to have a better conversation with your doctor.
• 6:22
  SPEAKER_00: Instead of asking which test is best, I want you asking, what is this test actually looking for?
• 6:29
  SPEAKER_00: What could it miss?
• 6:31
  SPEAKER_00: And would knowing the answer change what we do?
• 6:34
  SPEAKER_00: If this kind of practical preventive cardiology is helpful, subscribe and send this to someone debating between a calcium score, CIMT, carotid ultrasound, or coronary CT angiogram.
• 6:46
  SPEAKER_00: A coronary calcium score is a quick CT scan that doesn't require IV contrast.
• 6:52
  SPEAKER_00: It measures calcified hard plaque in the coronary arteries.
• 6:56
  SPEAKER_00: And a calcium artery calcium score is a strong predictor of future cardiovascular risk.
• 7:02
  SPEAKER_00: When CAC and CIMT have been compared head to head, calcium scoring has consistently done a better job predicting coronary events.
• 7:12
  SPEAKER_00: Calcium scoring is a very good test for the question it answers.
• 7:16
  SPEAKER_00: But here's the key: it only identifies plaque that's already hard and calcified.
• 7:22
  SPEAKER_00: It does not directly show non-calcified soft plaque.
• 7:27
  SPEAKER_00: And especially in younger patients, sometimes plaque may be present long before significant calcium develops.
• 7:34
  SPEAKER_00: And I want to be clear, this isn't just a younger patient issue.
• 7:38
  SPEAKER_00: I read these coronary CT angiograms myself, and even in patients in their 60s and 70s, I'll sometimes see a lot more non-calcified plaque than calcified plaque.
• 7:49
  SPEAKER_00: It's not something you simply age out of.
• 7:52
  SPEAKER_00: So when your calcium score is zero, what does it actually mean?
• 7:56
  SPEAKER_00: It means we did not detect calcified coronary plaque.
• 8:01
  SPEAKER_00: It does not mean there's no coronary plaque at all.
• 8:05
  SPEAKER_00: And this isn't a small number.
• 8:07
  SPEAKER_00: Up to about one in six people with no symptoms of heart disease and a calcium score of zero still have non-calcified plaque when we actually look at it with a coronary CT angiogram.
• 8:21
  SPEAKER_00: That's not rare.
• 8:22
  SPEAKER_00: That's a real number of people walking around with a reassuring zero and plaque they don't have.
• 8:29
  SPEAKER_00: Most of these patients don't have a dangerous 90% blockage, a major blockage in someone with no symptoms, and a CAC of zero is uncommon.
• 8:39
  SPEAKER_00: So I'm not trying to take a reassuring zero and turn it into something scary.
• 8:44
  SPEAKER_00: A calcium score of zero is reassuring.
• 8:46
  SPEAKER_00: It identifies a low-risk group overall, but low risk is not the same thing as no plaque.
• 8:53
  SPEAKER_00: And sometimes that distinction matters.
• 8:55
  SPEAKER_00: Let me spend a minute on why both soft non-calcified plaque and hard calcified plaque matter.
• 9:03
  SPEAKER_00: I already actually have an entire video on plaque itself.
• 9:06
  SPEAKER_00: I'll link it below in the comments.
• 9:09
  SPEAKER_00: People sometimes hear soft plaque and hard plaque and think soft is bad and calcified as good.
• 9:15
  SPEAKER_00: That's too simplistic.
• 9:17
  SPEAKER_00: Calcified plaque is still plaque, it's still athosclerosis.
• 9:21
  SPEAKER_00: Plaque changes over time.
• 9:24
  SPEAKER_00: Some is predominantly non-calcified, and it can become more calcified as it evolves, heals, and remodels.
• 9:32
  SPEAKER_00: Some of the plaque features associated with greater vulnerability, meaning a higher chance that piece of plaque could rupture and trigger a clot, show up specifically within the non-calcified soft portion of that plaque.
• 9:48
  SPEAKER_00: So my point isn't that calcium doesn't matter.
• 9:52
  SPEAKER_00: It's that if I only measure calcium, I'm only seeing one component of the total plaque burden.
• 9:58
  SPEAKER_00: And many times I want the whole picture.
• 10:01
  SPEAKER_00: That's why I made the scan that shows all plaque linked below.
• 10:05
  SPEAKER_00: And this isn't just theoretical.
• 10:07
  SPEAKER_00: We also have growing evidence that the soft plaque, a coronary CT angiogram C's, beyond calcium, carries real information.
• 10:16
  SPEAKER_00: In a 2025 analysis from the iconic study, which followed people who already had symptoms and later went on to have a heart attack, close to one in five had a calcium score of zero at the start.
• 10:31
  SPEAKER_00: And the ones who went on to have an event had a lot more soft plaque on their scan than similar people whose score was also zero, but who stayed fine.
• 10:42
  SPEAKER_00: This was in people who already had symptoms, not a healthy screening population.
• 10:47
  SPEAKER_00: But the point stands a calcium score can miss soft plaque that actually matters.
• 10:53
  SPEAKER_00: So what does a coronary CT angiogram actually add?
• 10:58
  SPEAKER_00: It uses contrasts and lets us look directly at the coronary arteries.
• 11:02
  SPEAKER_00: We can see hard plaque, calcified plaque, non-calcified and soft plaque, mixed plaque, where it is, how much there is, and whether it's narrowing the artery.
• 11:13
  SPEAKER_00: And we're getting better and better at actually measuring how much plaque is there and what kind it is.
• 11:18
  SPEAKER_00: And this is where the evidence has genuinely moved forward.
• 11:22
  SPEAKER_00: And I want you to actually sit with this next stat for a second.
• 11:28
  SPEAKER_00: In the large scapus study, nearly 25,000 people with no symptoms of heart disease, researchers just published follow-up results after tracking this group for close to eight years.
• 11:41
  SPEAKER_00: Adding coronary CT angiogram plaque information read by a human radiologist or cardiologist, not AI, to the calcium score and the usual risk factors correctly caught roughly one additional person out of every seven who went on to have a coronary event.
• 12:01
  SPEAKER_00: People with just the calcium score and risk factors alone would have missed, without meaningfully increasing false alarms in people who never had one.
• 12:11
  SPEAKER_00: In medicine, that is a big jump in accuracy from a single added test.
• 12:16
  SPEAKER_00: Most things we add to a workup don't move the needle nearly that much.
• 12:20
  SPEAKER_00: So this wasn't just giving us more pictures.
• 12:23
  SPEAKER_00: The additional plaque information actually helped identify people at higher risk that calcium scoring alone missed.
• 12:31
  SPEAKER_00: Now, I'm not saying everybody needs a coronary CT angiogram.
• 12:34
  SPEAKER_00: I'm just saying it can provide real, meaningful information beyond the calcium score in the right patient.
• 12:41
  SPEAKER_00: Now let's talk about how I actually use this information in my own practice.
• 12:46
  SPEAKER_00: So why do I prefer a coronary CT angiogram?
• 12:49
  SPEAKER_00: This is where my approach may differ from someone who uses calcium scoring as their main imaging tool.
• 12:54
  SPEAKER_00: I very rarely order a calcium score anymore alone.
• 12:58
  SPEAKER_00: Though I absolutely can, and there are patients I definitely do.
• 13:03
  SPEAKER_00: Maybe someone doesn't want contrast, it's not a good they're not a good candidate for a CT angiogram, or the clinical question can genuinely be answered with the calcium score.
• 13:12
  SPEAKER_00: But generally, when I want to know whether someone actually has coronary atherosclerosis, I prefer to look at the coronaries themselves.
• 13:20
  SPEAKER_00: Cardiac CTs is one of my board certifications, and I routinely see people with a calcium score of zero or very low calcium who still have non-calcified plaque.
• 13:30
  SPEAKER_00: I've had patients who would not have treated themselves based on their calcium score.
• 13:36
  SPEAKER_00: They see a zero and they think they're fine.
• 13:39
  SPEAKER_00: Then I show them the corner CT angiogram and there's plaque and non-calcified plaque, the more vulnerable soft kind.
• 13:46
  SPEAKER_00: Now the conversation is completely different.
• 13:50
  SPEAKER_00: We're no longer talking about theoretical risk factors.
• 13:53
  SPEAKER_00: We know plaque is already present.
• 13:56
  SPEAKER_00: So how does that actually change my plan?
• 13:58
  SPEAKER_00: When I say it changes management, I don't mean everybody gets the same medication because I find one tiny plaque.
• 14:04
  SPEAKER_00: Once I know there's plaque, I go back to the buckets I've already talked about before.
• 14:10
  SPEAKER_00: Cholesterol particles like APOB, insulin resistance and metabolic health, inflammation, blood pressure, genetics, and lifestyle.
• 14:18
  SPEAKER_00: And I figure out which of these buckets is actually driving it for that specific person.
• 14:25
  SPEAKER_00: Then we build a prevention plan together.
• 14:28
  SPEAKER_00: Finding coronary plaque may change how aggressive I want to be with that LDL or APOB lowering.
• 14:35
  SPEAKER_00: It may change the goals I'm aiming for, or make me investigate why someone is developing plaque despite fairly normal conventional labs.
• 14:43
  SPEAKER_00: And it may change a patient's own willingness to treat their risk factors.
• 14:48
  SPEAKER_00: There's a very different conversation between your cholesterol may increase your future risk, and we can actually see coronary plaque already developing in your artery.
• 14:58
  SPEAKER_00: This is exactly why early detection matters so much to me.
• 15:02
  SPEAKER_00: I want to find coronary disease before someone develops a major blockage in the first place.
• 15:08
  SPEAKER_00: A heart attack doesn't necessarily come from a plaque that was 90% blocked for years.
• 15:12
  SPEAKER_00: Many acute coronary events arise from lesions and blockages that weren't severely obstructive beforehand.
• 15:20
  SPEAKER_00: In the Promise trial, more than half of the major cardiac events occurred in patients whose baseline narrowing was under 50%.
• 15:30
  SPEAKER_00: They had no symptoms at all.
• 15:32
  SPEAKER_00: We've historically spent so much time asking, do you have a severe blockage?
• 15:36
  SPEAKER_00: But the better prevention question may sometimes be, do you have coronary atherosclerosis at all?
• 15:42
  SPEAKER_00: I'd much rather know about that disease early enough to treat it than have the first clue be an acute event.
• 15:49
  SPEAKER_00: And for many people, that heart attack is the first time they ever even know they have coronary disease.
• 15:55
  SPEAKER_00: So, does everyone need a coronary CT angiogram?
• 15:58
  SPEAKER_00: Absolutely not.
• 15:59
  SPEAKER_00: I talk about them a lot and I use them frequently, but that doesn't mean everyone watching should schedule one tomorrow.
• 16:05
  SPEAKER_00: Before ordering any test, I want a good discussion.
• 16:08
  SPEAKER_00: What are we trying to learn?
• 16:09
  SPEAKER_00: What do we already know?
• 16:11
  SPEAKER_00: What's the patient's age and overall risk?
• 16:13
  SPEAKER_00: Family history, labs, are there any symptoms?
• 16:17
  SPEAKER_00: And most importantly, will the results actually change what I do?
• 16:22
  SPEAKER_00: There are real considerations too.
• 16:24
  SPEAKER_00: It requires contrast, kidney function matters, contrast allergy history matters, heart rate and rhythm can affect the image quality, and very heavy calcium can sometimes make interpretation harder.
• 16:38
  SPEAKER_00: And there's also radiation.
• 16:40
  SPEAKER_00: Actually, one of the questions I get asked most often.
• 16:42
  SPEAKER_00: So I have an entire dedicated video coming soon on radiation from cardiac CT and coronary CT angiograms, what those numbers actually mean and how I think about risk versus benefit.
• 16:54
  SPEAKER_00: So, what should you actually ask your doctor?
• 16:58
  SPEAKER_00: This may be the most practical part of the video.
• 17:01
  SPEAKER_00: I'm not telling you to walk in and demand a coronary CT angiogram.
• 17:05
  SPEAKER_00: I want you to know what conversations to have.
• 17:09
  SPEAKER_00: Ask, what exactly are we trying to find out with this test?
• 17:13
  SPEAKER_00: If a calcium score is recommended, then ask, if my score is zero, could I still have non-calcified plaque?
• 17:21
  SPEAKER_00: If you're considering carotid imaging, ask, are we looking for actual plaque or specifically measuring CIMT?
• 17:30
  SPEAKER_00: If carotid plaque is found, you want to ask, since I already have plaque in one artery, should we also look at my coronary arteries?
• 17:39
  SPEAKER_00: If your carotid ultrasound is normal, you want to ask, does this actually tell us anything definitive about my coronary arteries?
• 17:48
  SPEAKER_00: And if you have a strong family history, elevated lipoprotein A, or other significant risk factors, I would ask, would knowing whether I already have coronary plaque change how aggressively we manage my risk?
• 18:02
  SPEAKER_00: If a coronary CT angiogram is being considered, also ask whether there's a center nearby that does high-quality coronary CT angiograms regularly.
• 18:12
  SPEAKER_00: The scanner, the protocol, the heart rate preparation, and the experience of the people performing and interpreting these scans all genuinely matter.
• 18:21
  SPEAKER_00: Here's a bottom line.
• 18:23
  SPEAKER_00: CIMT, carotid ultrasound, calcium scoring, and a coronary CT angiogram are not substitutes for one another.
• 18:31
  SPEAKER_00: CIMT measures carotid wall thickness.
• 18:33
  SPEAKER_00: Actual carotid plaque tells me plaque is present in the carotids.
• 18:38
  SPEAKER_00: And if I find it, I also want to understand what the heart arteries look like.
• 18:42
  SPEAKER_00: A calcium score looks directly at the heart, but only at calcified plaque.
• 18:46
  SPEAKER_00: And again, up to one in six people with no symptoms of heart disease and a calcium score of zero still have non-calcified soft plaque.
• 18:55
  SPEAKER_00: A coronary CT angiogram can show both.
• 18:58
  SPEAKER_00: So advocate for yourself.
• 18:59
  SPEAKER_00: Ask your doctor what test is going to be best for you.
• 19:02
  SPEAKER_00: Make sure you get the labs checked.
• 19:05
  SPEAKER_00: And if you're interested for more videos on early detection and prevention, subscribe to my YouTube channel and like for more.
• 19:13
  SPEAKER_00: Next up is my video on menopause and women's heart disease and what happens during menopause.
• 19:21
  SPEAKER_00: See you in the next one.