LCD L39521: Positron Emission Tomography (PET) Scan for Inflammation and Infection

Positron emission tomography (PET) is a non-invasive diagnostic imaging procedure utilized to assess the level of metabolic activity and perfusion of the organ systems. The positron camera (tomograph) produces cross-sectional tomographic images which are obtained from intravenously administered positron emitting radioactive tracer substances (radiopharmaceuticals) such as 2-[F-18] fluoro-d-glucose (FDG).

The noncoverage NCD for PET scan used for inflammation and infection (220.6.16) retired effective January 1 st 2021. 1 This NCD addressed the use of PET scan for non-oncological indications specific to inflammatory or infectious etiologies including fever of unknown origin, several cardiac conditions, osteomyelitis and infected artificial joints.

Definitions

First-line therapy is an agent used in the initial treatment of a condition.

An adverse event is a documented event that contraindicates further use of the medication or side effects that are not likely to be transient and resolve with further treatment or impair functional capacity and/or daily living activities.

Lack of efficacy is the lack of an expected or desired effect related to therapy when the dosage and duration of therapy meet published standards.

Refractory disease is when the patient fails to respond to all first-line therapies that are standard of care for the condition.

Relapse disease is a recurrence of the disease condition that does not respond to first-line treatments and/or standard of care therapies.

Fever of unknown origin defined as fever higher than 38.3 Celsius (101 degrees Fahrenheit) on several occasions, duration of at least three weeks and uncertain diagnosis after evaluation. 2

Fever- temperature of 101 degrees Fahrenheit or 38.3 Celsius

Immunocompromised (defined as neutropenia for at least one week in the three months before the start of the fever, known HIV infection, hypogammaglobulinemia or use of 10 milligrams Prednisone or equivalent for at least two weeks in the three months before the start of the fever) 3

Coverage

A. Fever of Unknown Origin (FUO)

PET Scan will be considered reasonable and medically necessary for patients ≥ 18 years old for FUO when all of the following conditions are met:

• Fever higher than 38.3 Celsius (101 degrees Fahrenheit) 2,4 AND

• Present for ≥ 21 days defined by fever on ≥ 2 occasions with repeating episodes for ≥ 2 weeks prior to study 4,5 AND

• The patient is not immunocompromised 3,4 AND

• Investigation including history, physical, laboratory analysis and standard imaging is non-diagnostic 6 AND

• Patient does not have any conditions that would limit the ability to interpret the PET scan 7

B. Cardiac

PET scan for evaluation of cardiac sources of infection and inflammation is considered reasonable and medically necessary when:

• Clinical exam and laboratory evaluation lead to clinical suspicion of the condition and this is documented in the medical record AND

• Non-specific or inconclusive imaging from echocardiography and/or CT 6 AND

• PET scan is conducted with cardiac preparation protocol 8,9 AND

• Patient does not have any conditions that would limit the ability to interpret the PET scan (such as recent cardiac/vascular surgery) 10 AND

• The patient is being evaluated for one of the following conditions and the specific criteria has been met:

• Infective Endocarditis: the patient has a prosthetic valve

Device Infections (pacemaker, defibrillators, LVAD, metallic implants) suspected.

Cardiac Sarcoidosis:

The patient has risk factor cardiac sarcoidosis (such as systemic sarcoidosis with cardiac findings) OR

A patient 11 OR

idiopathic sustained ventricular tachycardia unexplained by other causes 12 AND/OR

For guiding subsequent treatment of proven cardiac sarcoidosis if PET scan is the primary test used to follow the patient for the cardiac aspect of sarcoidosis/inflammatory cardiomyopathies (additional studies such cardiac MRI, CT or other nuclear imaging studies for the same purpose are non-covered). 13

Infection of cardiovascular implantable electronic devices:

Diagnosis is inconclusive on standard imaging (echo/CT)

Additional diagnostic studies would impact clinical care (such as decision to remove device or support prolonged antibiotic therapy or not)

Vascular graft infection

• Diagnosis is inconclusive with one of CTA or MRA

• Patient does not have any conditions that would limit the ability to interpret the PET scan

• Additional diagnostic studies would impact clinical care

• Aortitis and Systemic Vasculitis

• Diagnosis is inconclusive with one of CTA or MRA

• Patient does not have any conditions that would limit the ability to interpret the PET scan

• Additional diagnostic studies would impact clinical care

C. Osteomyelitis and Spondylodiscitis

PET Scan will be considered reasonable and medically necessary for diagnosis of equivocal cases of suspected osteomyelitis or spondylodiscitis (with abnormal radiographs or CT findings) when all of the following conditions are met:

• MRI cannot be performed or is non-diagnostic or inconclusive AND

• Patient does not have any conditions that would limit the ability to interpret the PET (such as post-operative or post-traumatic, uncontrolled blood sugars) AND

• Not in conjunction with bone scintigraphy, leukocyte scintigraphy, and/or MOAB scintigraphy

Limitations:

1. The need for PET scan and labeled WBC scan as part of diagnostic evaluation is rare. Individual consideration may be given on redetermination (appeal) for payment in rare, unique circumstances if the medical necessity of both studies and clearly documented in the medical record. Frequent reporting of these services together may trigger focused medical review.

2. The need for PET scan and 67Ga SPECT/CT as part of diagnostic evaluation is rare. Individual consideration may be given on redetermination (appeal) for payment in rare, unique circumstances if the medical necessity of both studies and clearly documented in the medical record. Frequent reporting of these services together may trigger focused medical review.

3. The need for PET scan and cardiac MRI as part of diagnostic evaluation is rare. Individual consideration may be given on redetermination (appeal) for payment in rare, unique circumstances if the medical necessity of both studies and clearly documented in the medical record. Frequent reporting of these services together may trigger focused medical review.

4. Endocarditis- PET scan is not reasonable and necessary for use in native value.

5. PET and PET/CT is not a first-line test and reserved for equivocal diagnostic cases. Use as a first-line study is not considered reasonable and necessary.

6. 18F-PET and PET/CT is not well-established to monitoring response to treatment and use outside of diagnosis is not considered reasonable and necessary with the exception cardiac sarcoidosis.

The following is not considered reasonable and medically necessary:

The use of PET scan for inflammation and infection of other conditions not specifically addressed above will be considered investigational.

Throughout the evidence review (18)F-fluorodeoxyglucose positron emission tomography-computed tomography will be referred to as 18F-PET or 18F-PET/CT.

Contractor Advisory Meeting (CAC)

A CAC meeting on “Pet Scans for Inflammation and Infection” was held on 11/09/22 and subject matter experts (SMEs) reviewed pertinent literature and provided input for the development of this policy. The transcripts and recording are available in the CGS Administrators website: https://www.cgsmedicare.com/partb/medicalpolicy/lcd_discussion_recordings.html. Reference to the SME input will be included throughout the policy.

Fever of Unknown Origin (FUO)