Acute Myocardial Infarction on Chest CT: The Proximal LAD Occlusion and Subendocardial Perfusion Defect That Radiologists Must Not Miss
A Radiologist’s Guide to Recognizing Myocardial Ischemia on Contrast-enhanced CT
Clinical Hook
A man in his late 40s arrived with sudden chest pain.
The initial clinical question was not necessarily “Can CT diagnose myocardial infarction?” In an emergency department, the more immediate concern in a patient with acute chest pain may be to exclude other life-threatening conditions such as aortic dissection, pulmonary embolism, or another acute thoracic process.
But the CT contained a second, potentially decisive message.
The myocardium was not enhancing uniformly.
A relatively hypoenhancing region extended through the left ventricular anterior wall toward the apex, with involvement of the interventricular septal and apical inferior myocardial regions. More importantly, the myocardial abnormality followed a recognizable coronary distribution. At the same time, the proximal left anterior descending artery demonstrated occlusion associated with noncalcified plaque.
The diagnosis was acute myocardial infarction, and the patient was transferred immediately for coronary angiography and stent placement in the LAD.
This is precisely the kind of case in which the radiologist can change the trajectory of care.
The lesson is not that chest CT replaces ECG, high-sensitivity cardiac troponin, echocardiography, CCTA, or invasive coronary angiography.
The lesson is simpler—and more important:
When a patient presents with acute chest pain, the heart itself must be part of the CT search pattern.
Learning Objectives
After reading this case, the reader should be able to:
Recognize subendocardial myocardial hypoenhancement as an important CT clue to myocardial ischemia or infarction.
Understand why the combination of myocardial perfusion abnormality and proximal LAD occlusion is clinically powerful.
Distinguish incidental myocardial abnormalities on routine chest CT from findings that require urgent communication.
Understand the complementary roles of conventional chest CT, CCTA, cardiac MRI, and invasive coronary angiography.
Recognize the limitations of CT-based diagnosis and avoid delaying reperfusion therapy in patients with suspected acute coronary syndrome.
Understand how AI, radiomics, automated plaque analysis, and workflow orchestration may augment—but not replace—the radiologist.
1. Anatomy Review: Why the LAD Matters
The left anterior descending artery is one of the most clinically important coronary arteries because it supplies a substantial portion of the left ventricular myocardium.
Its branches provide blood flow to much of the:
anterior left ventricular wall,
interventricular septum,
anteroseptal myocardium,
and apex.
Therefore, a proximal LAD occlusion can threaten a relatively large myocardial territory.
The anatomy becomes especially important when interpreting CT.
A focal myocardial perfusion abnormality should not be interpreted in isolation. The radiologist should ask whether the abnormality conforms to a vascular territory.
In this case, the perfusion abnormality extended from the anterior wall toward the apex, while the proximal LAD was occluded. The anatomical relationship between the culprit vessel and affected myocardium is therefore a critical diagnostic clue.
Figure 1. Coronary Anatomy Relevant to Proximal LAD Occlusion
2. Case Presentation
History
A man in his late 40s presented with acute chest pain. The case description emphasizes the sudden nature of the chest discomfort and the subsequent CT evaluation.
Symptoms
Acute myocardial infarction classically presents with:
pressure-like or squeezing retrosternal chest pain,
radiation to the arm, shoulder, neck, or jaw,
diaphoresis,
dyspnea,
nausea or vomiting.
However, myocardial infarction does not always produce textbook symptoms. Older adults and patients with diabetes may present with dyspnea, fatigue, or less characteristic symptoms.
Physical Examination
Specific physical examination findings were not provided in the case material and should therefore not be invented.
In real-world practice, assessment of hemodynamic stability, signs of heart failure, arrhythmia, shock, and ongoing ischemia would be essential.
Clinical Question
The immediate clinical question in a patient with acute chest pain is whether acute coronary syndrome is present and whether urgent reperfusion is required.
The standard diagnostic framework integrates:
clinical presentation,
ECG,
high-sensitivity cardiac troponin,
imaging,
and the temporal evolution of the suspected ischemic event.
The Fourth Universal Definition of Myocardial Infarction emphasizes that myocardial infarction is diagnosed through integration of clinical, electrocardiographic, biochemical, and imaging evidence rather than through one isolated test.
Laboratory Findings
The case material identifies high-sensitivity cardiac troponin as the key biomarker for myocardial injury but does not provide a numerical troponin value.
Therefore, the appropriate interpretation is:
hs-cTn would be expected to be a critical component of the diagnostic work-up, but the actual value is not available in this case.
This distinction matters. Troponin elevation indicates myocardial injury, but myocardial infarction requires clinical evidence of ischemia. Other conditions can also produce elevated troponin.
CT Findings
The major CT abnormalities were:
Subendocardial hypoenhancement/perfusion defect of the left ventricular myocardium.
Extension from the anterior wall toward the apex.
Additional involvement of the interventricular septal and apical inferior myocardial regions.
Proximal LAD occlusion associated with noncalcified plaque.
MRI Findings
No cardiac MRI examination was documented in the case material.
Therefore, MRI findings should not be presented as findings from this patient.
However, cardiac MRI would be particularly valuable if performed because late gadolinium enhancement can characterize the distribution and transmural extent of myocardial infarction and can help distinguish acute/subacute infarction from chronic scar.
Pathology
No histopathologic specimen was reported.
The diagnosis was established clinically and radiologically, followed by coronary intervention.
Final Diagnosis
Acute myocardial infarction associated with proximal LAD occlusion and corresponding subendocardial myocardial perfusion abnormality.
The patient subsequently underwent urgent coronary angiography and LAD stent placement.
3. Pathophysiology
The fundamental mechanism of acute myocardial infarction is interruption of myocardial blood supply sufficient to produce myocardial injury.
In the most common Type 1 myocardial infarction, atherosclerotic plaque disruption—through rupture or erosion—can lead to thrombus formation and coronary artery obstruction. The Fourth Universal Definition distinguishes Type 1 MI from Type 2 MI, in which myocardial ischemia results from an oxygen supply-demand mismatch without the same primary plaque-disruption mechanism.
From Plaque to Infarction
The sequence can be conceptualized as:
Initially, ischemia may be reversible.
With persistent severe reduction in coronary flow, cellular energy failure progresses. The subendocardial myocardium is particularly vulnerable because it experiences relatively high wall stress and is exposed to lower perfusion pressure during the cardiac cycle.
This explains an important imaging principle:
Subendocardial involvement is not an arbitrary imaging pattern. It reflects the biology of myocardial ischemia.
As ischemic injury progresses, the region of necrosis may extend from the subendocardium toward the epicardium.
This concept is central to understanding myocardial infarction on both CT and cardiac MRI.
Figure 2. From Proximal LAD Occlusion to Subendocardial Infarction
Proximal LAD occlusion reduces blood flow to the anterior wall, septum, and apex. Persistent ischemia produces myocardial injury, with the subendocardium particularly vulnerable to ischemic damage.
4. Epidemiology
The source case cites a systematic review estimating global myocardial infarction prevalence at approximately 4% among individuals younger than 60 years and approximately 9.5% among individuals aged 60 years or older.
The precise prevalence varies according to study design, population, diagnostic definition, age structure, and healthcare access.
Table 1. Epidemiologic and Clinical Risk Profile
| Parameter | Key Point |
|---|---|
| Age | Risk increases with age, but middle-aged adults can develop acute MI |
| Sex | Historically higher incidence in men at younger ages |
| Hypertension | Major modifiable cardiovascular risk factor |
| Diabetes | Strongly associated with coronary artery disease |
| Dyslipidemia | Important contributor to atherosclerotic plaque formation |
| Smoking | Major preventable risk factor |
| Obesity | Associated with cardiometabolic risk |
| Family history | Important marker of inherited risk |
| Chronic kidney disease | Associated with increased cardiovascular risk |
| Previous CAD | Strong predictor of future events |
The clinical message from this particular case is important: age alone should never be used to dismiss acute coronary syndrome.
5. Clinical Presentation and Red Flags
The classic presentation is acute pressure-like chest discomfort.
However, the diagnostic threshold should be lower when chest pain is accompanied by:
diaphoresis,
dyspnea,
nausea,
radiation to the arm or jaw,
syncope,
hemodynamic instability,
new ECG abnormalities,
or elevated hs-cTn.
Red Flags for Immediate Action
A radiologist reviewing CT should become particularly concerned when three elements converge:
acute chest symptoms + myocardial perfusion abnormality + culprit coronary abnormality
This combination has a substantially different clinical significance from an isolated, equivocal myocardial density difference.
6. Imaging Features: The Core Radiology Analysis
This is where the case becomes particularly valuable.
The CT was not simply “abnormal.”
It contained a recognizable physiological pattern.
Figure 3. Axial CT
The axial contrast-enhanced CT demonstrates relatively reduced myocardial attenuation involving the left ventricular myocardium, particularly along the subendocardial region.
Radiologist Interpretation
The abnormality is characterized by:
focal myocardial hypoenhancement,
subendocardial predominance,
left ventricular distribution,
and a pattern that should be assessed against coronary anatomy.
The key question is not simply:
“Is this part of the myocardium darker?”
The more useful question is:
“Does this myocardial hypoenhancement represent a vascular-territory abnormality?”
When the answer is yes, myocardial ischemia or infarction rises substantially in the differential.
Clinical Imaging Interpretation
Myocardial attenuation on contrast CT depends on blood flow and contrast delivery.
A region supplied by an acutely occluded coronary artery may receive less contrast during the acquisition and consequently appear relatively hypoenhancing.
The finding is therefore a functional consequence of vascular obstruction.
Diagnostic Imaging Pearls
Compare adjacent myocardial segments.
Look specifically for subendocardial involvement.
Determine whether the abnormality follows a coronary territory.
Inspect the LAD, LCX, and RCA when technically feasible.
Use multiplanar reconstructions.
Consider motion artifact before calling subtle coronary abnormalities.
7. Coronal CT: Why Multiplanar Reconstruction Matters
Figure 4. Coronal CT
The coronal reconstruction demonstrates the continuity of the myocardial perfusion abnormality from the anterior wall toward the apex.
Radiologist Interpretation
A finding that appears nonspecific on a single axial image can become much more convincing when demonstrated across multiple planes.
Coronal reconstruction is particularly helpful for assessing:
cranio-caudal extent,
continuity of myocardial involvement,
relationship to the ventricular apex,
and the distribution of the abnormality.
Clinical Significance
Multiplanar assessment reduces the risk of dismissing a real lesion as an artifact.
In cardiac CT, this is particularly important because cardiac motion can create misleading attenuation differences.
8. Sagittal CT: Identifying the Apex
Figure 5. Sagittal CT
Sagittal reconstruction demonstrates the longitudinal extension of the myocardial abnormality toward the left ventricular apex.
The apex is an important anatomical landmark in LAD-territory ischemia.
When a myocardial perfusion abnormality extends toward the apex and a proximal LAD lesion is present, the radiologist should actively correlate these two observations.
This is more clinically meaningful than reporting either finding independently.
9. Proximal LAD Occlusion: The Critical Vascular Finding
An additional axial CT image demonstrates the coronary abnormality, with the final interpretation identifying proximal LAD occlusion associated with noncalcified plaque.
The diagnostic power comes from the combination:
Proximal LAD occlusion + matching myocardial perfusion abnormality
A coronary lesion without myocardial consequences may represent chronic disease.
A myocardial perfusion abnormality without a visible coronary culprit may require a broader differential.
But when the vascular and myocardial abnormalities map onto the same territory, the probability of a clinically meaningful acute coronary event becomes much higher.
10. Why Subendocardial Hypoenhancement Matters
The subendocardium is especially susceptible to ischemia.
Therefore, subendocardial hypoenhancement in an appropriate clinical setting is a biologically meaningful pattern.
The radiologist should ask:
Is the abnormality real?
Is it reproducible across planes?
Does it follow a coronary territory?
Is there a culprit coronary lesion?
Is the clinical presentation compatible with ACS?
Are ECG and hs-cTn supportive?
Is urgent clinical communication required?
The source case emphasizes that a regional myocardial perfusion abnormality should not be dismissed simply because the CT was originally acquired for another thoracic indication.
11. CT Is Not the Same as CCTA
This distinction is essential.
A conventional contrast-enhanced chest CT and coronary CT angiography are not interchangeable examinations.
CCTA is optimized for coronary assessment through factors such as:
ECG synchronization,
appropriate temporal resolution,
contrast timing,
dedicated acquisition,
and optimized reconstruction.
CAD-RADS 2.0 was specifically developed to standardize CCTA reporting and incorporates stenosis severity, plaque burden, and optional ischemia assessment through CT-FFR or myocardial CT perfusion.
Therefore, the presence of a coronary abnormality on a routine chest CT should not be interpreted as equivalent to a formally acquired diagnostic CCTA.
At the same time, a technically imperfect examination can still contain a clinically decisive finding.
That is the practical lesson of this case.
12. Multimodal Imaging Comparison
| Modality | Major Strength | Major Limitation | Clinical Value |
|---|---|---|---|
| Conventional Chest CT | Rapid assessment of thoracic structures and incidental myocardial abnormalities | Not optimized for coronary arteries | Can reveal unexpected myocardial ischemia/infarction |
| CCTA | Excellent noninvasive coronary anatomical assessment | Requires optimized acquisition and may be limited by motion/calcification | Coronary stenosis, plaque, and selected acute chest pain pathways |
| CT Perfusion | Functional myocardial perfusion information | Radiation and contrast considerations | Anatomical-functional integration |
| Cardiac MRI | Excellent tissue characterization | Availability, time, contraindications | Infarct extent, viability, scar, edema |
| DWI | Tissue water diffusion assessment | Technical challenges in cardiac imaging | Limited but evolving role |
| ADC | Quantitative diffusion information | Susceptible to technical variability | Research/adjunctive tissue characterization |
| SWI | Sensitive to susceptibility effects | Not a routine MI sequence | Limited role in myocardial infarction |
| Contrast MRI/LGE | Excellent infarct distribution and transmurality assessment | Gadolinium and MRI limitations | Myocardial viability and scar characterization |
Cardiac MRI remains particularly important for tissue characterization. Late gadolinium enhancement can demonstrate infarct distribution and transmurality, while CT is particularly useful when rapid anatomical assessment is required.
13. Acute versus Chronic Myocardial Infarction
This distinction is clinically important.
The case material specifically highlights myocardial wall changes and calcification as potential clues to chronic infarction and notes the value of delayed enhancement imaging for distinguishing acute from chronic injury.
14. Imaging Differential Diagnosis
Table 2. Differential Diagnosis of Regional Myocardial Hypoenhancement on CT
| Diagnosis | CT | MRI | Pathology/Mechanism | Key Differentiating Point |
|---|---|---|---|---|
| Acute MI | Regional hypoenhancement, possible coronary occlusion | LGE, edema, infarct pattern | Acute ischemic necrosis | Coronary-territory distribution |
| Chronic MI | Possible thinning/calcification | LGE scar, wall thinning | Fibrosis/scar | Chronic remodeling |
| Motion artifact | Irregular or inconsistent attenuation | Variable | Technical | Disappears or changes across planes |
| Nonischemic cardiomyopathy | Variable | Characteristic noncoronary LGE patterns | Myocardial disease | Distribution does not follow one coronary artery |
| Myocarditis | Variable | Often subepicardial or mid-wall LGE | Inflammatory injury | Noncoronary distribution |
| Takotsubo syndrome | Usually nonspecific | Typical wall-motion pattern, usually no classic infarct LGE | Stress-mediated myocardial dysfunction | Distribution extends beyond one coronary territory |
The most important discriminator in this case is the concordance between the myocardial abnormality and proximal LAD occlusion.
15. Radiologist Reading Report
Findings
Contrast-enhanced CT demonstrates regional hypoenhancement of the left ventricular myocardium, predominantly involving the subendocardial aspect of the anterior wall and extending toward the apex. Additional myocardial involvement is present in the interventricular septal and apical inferior regions.
A proximal LAD occlusion associated with noncalcified plaque is identified.
The myocardial perfusion abnormality corresponds anatomically to the LAD territory.
Impression
1. Regional subendocardial myocardial hypoenhancement involving the anterior wall and apex, highly suspicious for acute myocardial ischemic injury/infarction in the appropriate clinical setting.
2. Proximal LAD occlusion associated with noncalcified plaque.
3. Given acute chest pain and the concordant myocardial and coronary findings, urgent cardiology/interventional cardiology evaluation is warranted.
This is a situation in which the radiologist should consider direct communication with the clinical team rather than relying solely on routine report delivery.
16. Clinical Correlation
The final diagnosis cannot rest on CT alone.
The Fourth Universal Definition of MI requires integration of clinical evidence, ECG, biomarkers, and imaging.
In this case, the clinical presentation, CT myocardial abnormality, proximal LAD occlusion, and subsequent urgent PCI form a coherent diagnostic chain.
The case therefore illustrates a critical principle:
Imaging should not be interpreted as an isolated anatomical exercise.
The radiologist's job is to identify the abnormality, understand its pathophysiology, determine its clinical significance, and communicate appropriately.
17. Treatment Strategy
The therapeutic priority in acute coronary syndrome with an occluded culprit artery is timely reperfusion.
The case patient underwent coronary angiography followed by LAD stent placement.
The 2025 ACC/AHA/ACEP/NAEMSP/SCAI guideline emphasizes rapid reperfusion strategies for appropriate patients with acute coronary syndromes, including primary PCI when indicated. The source case also highlights the importance of minimizing treatment delay.
The 2023 ESC guideline similarly provides a comprehensive ACS pathway covering diagnosis, risk stratification, invasive management, and long-term secondary prevention.
A crucial operational principle follows:
If the clinical picture strongly indicates an occlusive MI requiring immediate reperfusion, additional imaging should never become the reason for delaying reperfusion.
CCTA is valuable in appropriately selected patients, particularly intermediate-risk patients without diagnostic ECG findings and with uncertain initial biomarker results. A 2026 Radiology review emphasizes this role while distinguishing it from patients who already require immediate intervention.
18. Prognosis and Why Time Matters
Persistent coronary occlusion increases the amount of irreversible myocardial injury.
Potential complications include:
left ventricular systolic dysfunction,
heart failure,
ventricular arrhythmia,
cardiogenic shock,
papillary muscle dysfunction,
myocardial rupture,
recurrent hospitalization,
and long-term adverse cardiovascular outcomes.
Thus, the phrase “time is myocardium” remains clinically meaningful.
The radiologist may not perform the PCI, but the radiologist can shorten the interval between image acquisition and treatment.
That is a real clinical contribution.
19. A Practical Six-Step CT Search Pattern
For acute chest pain, a structured CT review can reduce the risk of overlooking myocardial abnormalities.
This workflow is directly aligned with the practical approach described in the case.
20. Artificial Intelligence Perspective
AI is increasingly entering cardiovascular CT, but the most useful applications are not necessarily “AI diagnosis of myocardial infarction” in isolation.
The more realistic future is an integrated workflow.
Radiomics
Radiomics can quantify myocardial and coronary characteristics that may be difficult to appreciate visually.
Potential features include:
attenuation heterogeneity,
texture,
plaque morphology,
calcium burden,
remodeling,
perivascular characteristics,
and myocardial enhancement patterns.
However, radiomic signatures are highly sensitive to acquisition parameters, reconstruction methods, scanner characteristics, and preprocessing.
A radiomic feature is therefore not automatically a clinically validated biomarker.
AI Plaque Quantification
Recent work has focused on automated plaque quantification from CCTA.
AI-based quantitative plaque analysis can potentially estimate plaque volume and composition and may improve risk stratification. However, current evidence still requires further validation regarding incremental prognostic value, reproducibility across scans, and clinically meaningful thresholds.
This distinction is important:
Automation is not the same as clinical validation.
Foundation Models
Future cardiovascular imaging systems may integrate:
CT images,
ECG,
troponin,
clinical history,
medication data,
previous imaging,
and outcomes.
A multimodal foundation model could theoretically estimate the probability of ACS and identify high-risk imaging patterns.
But such systems require rigorous external validation.
Vision-Language Models
A vision-language model could potentially:
identify myocardial hypoenhancement,
localize coronary abnormalities,
map the myocardial defect to a coronary territory,
generate a preliminary structured report,
identify a potential emergency,
and trigger a communication workflow.
The final decision, however, should remain under appropriate clinical oversight.
21. AI Workflow Architecture
Figure 6. AI-Augmented Acute Chest Pain Imaging Workflow
A future clinical AI system could integrate anatomical CT findings with myocardial perfusion abnormalities and clinical information. The AI should prioritize detection and workflow support rather than independently determine treatment.
22. PACS, HL7, FHIR and Enterprise AI
A clinically useful AI system cannot exist as an isolated algorithm.
The real architecture is:
DICOM is essential for image interoperability.
HL7 and FHIR can facilitate exchange of clinical information, including:
laboratory results,
ECG information,
medications,
encounter data,
diagnoses,
and clinical observations.
The future enterprise system should therefore connect imaging AI to the broader clinical workflow rather than creating another disconnected workstation.
For example:
CT shows possible myocardial ischemia → AI prioritizes study → radiologist confirms → structured alert generated → clinical team receives urgent notification.
That is substantially more valuable than simply placing a probability score next to an image.
23. AI Limitations
AI can fail in precisely the situations that matter most.
Potential failure modes include:
cardiac motion artifact,
poor contrast timing,
low cardiac output,
unusual coronary anatomy,
heavy calcification,
incomplete cardiac coverage,
scanner variability,
reconstruction differences,
dataset shift,
false-positive myocardial hypoenhancement,
and false-negative subtle ischemic changes.
An AI model may also detect an abnormality without understanding whether it is acute, chronic, incidental, or clinically relevant.
Therefore:
AI should identify, quantify, prioritize, and communicate—but the radiologist must interpret and contextualize.
24. Future of Precision Medicine
The next stage of cardiovascular imaging will likely move from anatomical diagnosis toward integrated phenotyping.
Radiogenomics
Imaging phenotypes may eventually be combined with genetic risk information to characterize individual susceptibility to coronary disease.
Digital Twin
A cardiovascular digital twin could theoretically integrate:
coronary anatomy,
myocardial perfusion,
ventricular function,
hemodynamics,
biomarkers,
treatment history,
and longitudinal outcomes.
Such a model could simulate disease progression and treatment response.
Federated Learning
Hospitals could potentially train AI systems across multiple institutions without centrally pooling all patient data.
This may improve generalizability while addressing some privacy concerns.
Synthetic Data
Synthetic cardiovascular CT datasets could help address data scarcity and enable controlled model development.
However, synthetic data cannot automatically reproduce the complexity of real-world disease.
Multimodal AI
The most clinically meaningful future model may not be a CT-only model.
It may be:
This is the direction in which precision cardiovascular imaging is likely to evolve.
Clinical Pearls
Acute chest pain should always trigger a deliberate review of the myocardium on contrast-enhanced CT.
Subendocardial hypoenhancement is an important clue to myocardial ischemia or infarction.
A coronary-territory distribution is more meaningful than isolated low attenuation.
Proximal LAD occlusion can threaten a large myocardial territory.
Always correlate myocardial abnormalities with coronary anatomy.
Review axial, coronal, and sagittal images.
Cardiac motion can mimic coronary and myocardial abnormalities.
Conventional chest CT is not equivalent to CCTA.
CCTA should not delay emergent reperfusion when an occlusive MI is already clinically evident.
hs-cTn is essential but should be interpreted in clinical context.
Chronic infarction may demonstrate myocardial thinning and calcification.
Cardiac MRI is particularly valuable for tissue characterization and infarct transmurality.
CAD-RADS standardizes CCTA reporting but does not replace individualized clinical judgment.
AI-based plaque quantification is promising but still requires broader validation.
The most important radiology contribution may be reducing the time from image recognition to clinical action.
Quiz
Question 1
A man in his late 40s presents with acute chest pain. Contrast-enhanced CT demonstrates a subendocardial perfusion defect extending from the anterior wall toward the apex and proximal LAD occlusion. Which laboratory marker is most directly relevant to myocardial injury?
① Hemoglobin
② Lipase
③ Cardiac troponin
④ CA 19-9
⑤ Amylase
Answer: ③ Cardiac troponin
Explanation: Cardiac troponin is a key biomarker of myocardial injury and is central to modern ACS diagnostic pathways. However, troponin elevation must be interpreted together with clinical and ECG evidence and cannot by itself establish Type 1 MI.
Question 2
Which is the most appropriate action when acute chest pain is accompanied by a coronary-territory myocardial perfusion defect and proximal LAD occlusion?
① Discharge the patient
② Repeat CT in one month
③ Urgent cardiology/interventional cardiology evaluation
④ Treat only with analgesics
⑤ Start antibiotics
Answer: ③ Urgent cardiology/interventional cardiology evaluation
Explanation: The combination of acute symptoms, myocardial perfusion abnormality, and culprit coronary occlusion is highly concerning for acute myocardial infarction. The case proceeded to urgent coronary angiography and LAD stenting.
Question 3
Which imaging feature is more suggestive of chronic myocardial infarction?
① Acute coronary occlusion with new myocardial hypoenhancement
② Myocardial wall thinning and calcification
③ Normal coronary arteries in every case
④ Absence of myocardial abnormalities
⑤ Normal cardiac MRI in all patients
Answer: ② Myocardial wall thinning and calcification
Explanation: Chronic infarction can produce remodeling, myocardial thinning, fibrosis, and calcification. Cardiac MRI with late gadolinium enhancement can further characterize established scar.
Question 4
Which statement about CCTA is most accurate?
① CCTA and conventional chest CT are identical examinations.
② CCTA is optimized for coronary artery evaluation.
③ CCTA should always be performed before PCI.
④ CCTA replaces ECG and troponin.
⑤ CCTA eliminates the need for clinical judgment.
Answer: ② CCTA is optimized for coronary artery evaluation.
Explanation: CCTA uses dedicated acquisition and reconstruction strategies for coronary assessment. CAD-RADS 2.0 provides a standardized framework for reporting CCTA findings.
Question 5
What is an important limitation of AI-based coronary plaque quantification?
① It cannot process CT data.
② It is never reproducible.
③ Its incremental prognostic value and reproducibility still require further validation.
④ It has completely replaced radiologists.
⑤ It cannot identify coronary plaque.
Answer: ③
Explanation: Current AI-QP systems are promising, but further evidence is required regarding reproducibility, meaningful progression thresholds, and incremental clinical value beyond established measurements.
FAQ
1. Can acute myocardial infarction be detected on a routine chest CT?
Yes. A routine contrast-enhanced chest CT may reveal myocardial hypoenhancement or other abnormalities suggestive of ischemia or infarction, particularly when the abnormality follows a coronary distribution.
2. Is chest CT the standard first-line test for acute myocardial infarction?
No. The diagnosis is based on clinical assessment, ECG, high-sensitivity cardiac troponin, and appropriate imaging. CT may reveal important findings incidentally or may be used in selected chest-pain pathways.
3. What is the most important CT finding in this case?
The combination of subendocardial myocardial perfusion abnormality and proximal LAD occlusion.
4. Why is subendocardial involvement important?
The subendocardium is particularly vulnerable to ischemia because of its physiological perfusion characteristics.
5. Does a coronary occlusion automatically prove acute myocardial infarction?
No. Clinical context, ECG, biomarkers, and imaging must be integrated.
6. What is the role of cardiac MRI?
Cardiac MRI is particularly useful for tissue characterization, infarct distribution, viability, edema, and scar assessment.
7. What is CAD-RADS?
CAD-RADS is a standardized reporting system for CCTA that categorizes stenosis, plaque burden, and selected modifiers such as ischemia assessment.
8. Can AI diagnose myocardial infarction automatically?
AI can assist with detection, segmentation, plaque quantification, prioritization, and decision support, but fully autonomous diagnosis remains inappropriate for many real-world clinical situations.
9. Should CCTA delay PCI?
No. When immediate reperfusion is indicated, additional imaging should not create an avoidable treatment delay.
10. What should a radiologist do after identifying a suspicious CT pattern?
Correlate the finding with the clinical context and communicate urgently with the appropriate clinical team when acute myocardial infarction is strongly suspected.
Conclusion
The most dangerous finding on a chest CT is not always located in the lungs.
Sometimes the critical abnormality is in the myocardium.
This case demonstrates why.
A man in his late 40s presented with acute chest pain. CT demonstrated a subendocardial myocardial perfusion defect extending toward the apex and a proximal LAD occlusion. The findings were anatomically concordant, the clinical suspicion was high, and the patient proceeded rapidly to coronary angiography and LAD stenting.
The case therefore illustrates an important radiology principle:
Do not interpret the CT indication instead of the CT itself.
A scan obtained to investigate chest pain may contain evidence of several different life-threatening diseases.
For the radiologist, the practical questions are straightforward:
Is myocardial enhancement symmetric?
Does any perfusion defect follow a coronary territory?
Is there a culprit coronary lesion?
Could this represent acute myocardial ischemia?
And finally:
Does the clinical team need to know now?
Modern CCTA has moved beyond simple stenosis measurement toward plaque characterization, ischemia assessment, CT-FFR, perfusion analysis, and standardized CAD-RADS reporting. The 2026 Radiology literature further emphasizes the growing role of CCTA in appropriately selected patients with acute chest pain.
AI will increasingly help identify these abnormalities, quantify plaque, prioritize cases, and integrate multimodal data. But AI does not eliminate the radiologist's responsibility.
The future is not:
AI versus radiologist.
It is:
AI detection → radiologist interpretation → clinical communication → timely intervention.
In acute myocardial infarction, that final interval may determine how much myocardium survives.
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[13] European Society of Cardiology, “2023 ESC Guidelines for the Management of Acute Coronary Syndromes,” 2023.
[14] American College of Cardiology/American Heart Association and collaborating societies, “2025 Guideline for the Management of Patients With Acute Coronary Syndromes,” 2025.
[15] R. Vliegenthart, M. Francone, M. C. Williams, and R. Salgado, “Coronary CT Angiography for Acute Chest Pain in the Emergency Department,” Radiology, 2026.
Medical Disclaimer
This article is intended for medical education and professional discussion. It does not replace clinical assessment, ECG, laboratory testing, specialist consultation, or established emergency management pathways. Individual patients with suspected acute coronary syndrome require immediate clinical evaluation and treatment according to current local protocols and guidelines.
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