Is a myocardial positron emission tomography (PET) scan with computed tomography (CT) medically necessary for a patient with elevated low-density lipoprotein (LDL) levels, impaired glucose regulation (A1C 6.4%), borderline elevated diastolic blood pressure, and potential cardiac issues on electrocardiogram (EKG), but no symptoms of chest pain or shortness of breath, and normal left ventricular systolic function with an ejection fraction (EF) of 60-64%?

Medical Necessity Assessment: PET Myocardial Perfusion Imaging

Direct Answer

PET myocardial perfusion imaging is NOT medically necessary for this patient and does not meet established appropriateness criteria. This asymptomatic patient with risk factors but no symptoms, normal LV function (EF 60-64%), and no evidence that exercise treadmill testing would be unreliable should undergo standard exercise stress testing first, not advanced imaging. 1

Why This Request Does Not Meet Criteria

Patient Does Not Have Symptoms Requiring Advanced Imaging

• The patient explicitly denies chest pressure, tightness, heaviness, or discomfort, and has shortness of breath only on severe exertion—this does not constitute anginal symptoms requiring functional imaging. 1
• Asymptomatic patients with risk factors alone are specifically NOT candidates for myocardial perfusion imaging according to multiple guidelines. 2, 1
• The 2011 systematic review of imaging guidelines found that for asymptomatic populations, guidelines were either against or found insufficient evidence for SPECT/PET imaging. 2

Exercise Treadmill Testing Has Not Been Performed or Proven Inadequate

• The patient jogs almost daily and has "very good" functional status—there is no indication that exercise treadmill testing would be unreliable or insufficient. 1
• The ACG criteria explicitly require that "exercise treadmill testing alone is or would be unreliable or inconclusive" before advanced imaging is appropriate—none of the listed conditions apply to this patient. 1
• The patient does NOT have: left bundle branch block, electronically paced rhythm, baseline ST depression ≥1mm, left ventricular hypertrophy with repolarization abnormalities, pre-excitation syndrome, atrial fibrillation, or inability to exercise. 1
• First-degree AV block alone does NOT make exercise testing unreliable. 1

Anterior T-Wave Changes on ECG Do Not Automatically Warrant PET

• While the patient has anterior T-wave changes on one ECG, this finding in an asymptomatic patient with normal LV function and excellent exercise capacity does not meet criteria for advanced imaging without first performing exercise stress testing. 1
• The European Society of Cardiology recommends MPI for patients with moderate to high pre-test likelihood (>15-85%) of obstructive CAD, but this patient's pre-test probability needs formal assessment through standard stress testing first. 1

Risk Factors Alone Are Insufficient Justification

• Elevated LDL (154 mg/dL), borderline elevated A1C (6.4%), and borderline diastolic hypertension are cardiovascular risk factors requiring medical management, not advanced cardiac imaging. 1
• The 2011 guideline review found that for asymptomatic patients at intermediate risk based on Framingham Risk Score, guidelines recommended AGAINST stress imaging or found insufficient evidence. 2
• Even coronary calcium scoring would be more appropriate than PET for risk stratification in this asymptomatic patient. 1

What Should Be Done Instead

Initial Appropriate Testing Pathway

• Perform standard exercise treadmill testing (Bruce protocol) as the initial diagnostic test. 1
• The patient's excellent functional status (jogs daily) makes him an ideal candidate for exercise ECG testing. 1
• Only if exercise testing is positive, equivocal, or demonstrates high-risk features should functional imaging be considered. 1

If Exercise Testing Were Truly Contraindicated or Unreliable

• Even if exercise testing were inappropriate (which it is not in this case), the patient would need to meet specific criteria for PET over other modalities. 1
• Pharmacologic stress echocardiography or cardiac MRI would be reasonable alternatives to PET and are less expensive. 1
• PET is preferred over SPECT when both are available due to higher diagnostic accuracy, but this preference does not override the requirement for appropriate patient selection. 1, 3

Critical Pitfall in This Case

The physician's statement that "PET stress would be best since this also screens for coronary calcium" reveals a fundamental misunderstanding. Coronary calcium scoring is performed with non-contrast CT and does not require PET imaging. 1 This conflation of two separate tests (calcium scoring via CT and perfusion imaging via PET) suggests the ordering physician may not fully understand the indications for these modalities.

Addressing the Specific CPT Codes

CPT 78431 (Myocardial PET Rest & Stress with CT)

• Not medically necessary: Patient does not meet criteria for stress imaging as first-line test. 1

CPT 78434 (Absolute Quantification of Myocardial Blood Flow)

• Not medically necessary: Quantitative flow reserve assessment is valuable when perfusion imaging is indicated, but does not expand indications to asymptomatic patients. 1, 4
• While research shows abnormal coronary flow reserve can be detected in asymptomatic high-risk patients, this remains a research application, not a clinical indication for routine testing. 4

Summary of Guideline-Based Recommendation

This patient requires aggressive medical management of his cardiovascular risk factors (statin therapy for LDL >150, diabetes management for A1C 6.4%, blood pressure control) and standard exercise treadmill testing if there is clinical concern for CAD. 1 Advanced imaging with PET should be reserved for patients who meet established appropriateness criteria, which this patient clearly does not. 2, 1