ACRAD41 – Use of Quantitative Criteria for Oncologic FDG PET Imaging

Measure Title: Use of Quantitative Criteria for Oncologic FDG PET Imaging

Measure Description Percentage of final reports for all patients, regardless of age, undergoing non-CNS oncologic FDG PET studies that include at a minimum:
a. Serum glucose (e.g., finger stick at time of injection)
b. Uptake time (interval from injection to initiation of imaging)
c. One reference background (e.g., volumetric normal liver or mediastinal blood pool) SUV measurement, along with description of the SUV measurement type (e.g., SUVmax) and normalization method (e.g., BMI)
d. At least one lesional SUV measurement OR diagnosis of “”no disease-specific abnormal uptake””

Denominator: All final reports for all patients, regardless of age, undergoing non-CNS oncologic FDG PET studies

Numerator: Final reports for FDG PET scans that include at a minimum:
a. Serum glucose (e.g., finger stick at time of injection)
b. Uptake time (interval from injection to initiation of imaging)
c. One reference background (e.g., volumetric normal liver or mediastinal blood pool) SUV measurement, along with description of the SUV measurement type (e.g., SUVmax) and normalization method (e.g., BMI)
d. At least one lesional SUV measurement OR diagnosis of “”no disease-specific abnormal uptake””

Denominator Exclusions: None

Denominator Exceptions: None

Numerator Exclusions: None

Published Specialty: Radiology

High Priority Measure: Yes

Measure Type: Process

Include Telehealth: No

Inverse Measure: No

Proportional Measure: Yes

Continuous Variable Measure: No

Ratio Measure: No

Score Range: N/A

Number of Performance Rates: 1

Performance Rate Description: Percentage of final reports for all patients, regardless of age, undergoing non-CNS oncologic FDG PET studies that include at a minimum:
a. Serum glucose (e.g., finger stick at time of injection)
b. Uptake time (interval from injection to initiation of imaging)
c. One reference background (e.g., volumetric normal liver or mediastinal blood pool) SUV measurement, along with description of the SUV measurement type (e.g., SUVmax) and normalization method (e.g., BMI)
d. At least one lesional SUV measurement OR diagnosis of “”no disease-specific abnormal uptake””

Risk Adjusted Status: No

MIPS Reporting Options: Traditional MIPS

Care Setting: Hospital Inpatient; Hospital Outpatient; Imaging Facility

Clinical Recommendation Statement: The following evidence statements are quoted verbatim from the referenced clinical guidelines and other sources, where applicable:
The technique section of the report should contain the radiopharmaceutical (eg, 18F-FDG), the administered activity, route and site of administration, as well as any pharmaceuticals administered (eg, diuretics, benzodiazepines). The serum glucose level at the time of radiopharmaceutical administration should be reported as well as patient weight, time from injection to scanning, and technique for calculating SUVs (ie, body weight, lean body weight, or body surface criteria). (ACR, 2016)
The findings section should include description of the location, extent, and intensity of abnormal FDG uptake in relation to normal comparable tissues and should describe the relevant morphological findings on the CT images. Ideally, image and series numbers should also be included. Additionally, background activity (eg, mediastinal blood pool and/or volumetric normal liver) should be measured to help compare SUV values. Often injection-site infiltrates, such as arms, or attenuation-correction errors can significantly alter SUV values in lesions, leading to false conclusions. An estimate of the intensity of FDG uptake can be provided with the SUV; however, the intensity of uptake may be described as mild, moderate, or intense in relation to the background update in normal hepatic parenchyma or the mediastinal blood pool. (ACR, 2016)

Measure Rationale: Importance/variation in care:

Results of imaging studies play an increasingly major role in oncology for diagnostic evaluation, development of treatment plans, and monitoring of treatment response. Results of FDG PET scans are communicated to referring health care providers and patients primarily via the diagnostic imaging report. However, there is significant variation in the format and content of ?nal reports. Many important components of PET studies are often missing from final reports including blood glucose level, SUV measurement, and the time from radiopharmaceutical injection to imaging. Such information also helps with contextual interpretation of SUV measurements for abnormal lesions. These measurements are important for technical comparisons between studies and from one center to another for a more reliable diagnosis. Excluding these components may adversely affect comparison with subsequent and prior studies.

Including the quantitative criteria in the report for a current exam provides important technical details that are the basis for many of the physiologic manifestations seen on the study. There are accepted and established standards for how PET/CTs should be optimally performed and varying from these parameters can affect the physiology and therefore the imaging findings. Including technical information like glucose level and time from injection can help interpreting clinicians know if the study was performed optimally and if the findings are anticipated to be reliable.

Second, particularly for cancer imaging, evaluation of change in disease/response to therapy is often dependent not only on size measurements of lesions, but also on the metabolic activity. The measurement of SUV values is a surrogate measure of relative metabolic activity and comparing SUV values between scans is frequently performed. However, the SUV measurement is a normalized value so it is important to mention the method of normalization (by weight, total mass etc.). Furthermore, it is very dependent technical variables including glucose level, time for injection of FDG, scanner and processing algorithm etc. As such, it can be tricky to compare SUV values between scanners/imaging centers unless similar techniques and protocols are employed.

One of the methods used to assess if, generally speaking, scans are acceptably similar and SUV values can be compared with decent reliability is by comparing a reference background measurement. This reference background measurement should always be obtained and ideally is one that is less susceptible to drug/disease related issues etc., such as the cerebellum as a standard measure.

The reporting of these data helps ensure that standard and appropriate protocol was performed and hence the study is believed to be interpretable and the findings are assumed to be real. It also is primarily helpful for comparisons among many studies. On occasion, such numbers and data may influence interpretation of certain findings (ie SUV value [and implied aggressiveness] of a particular lesion etc.) on the given scan.

If the SUV is measured for a lesion, most physicians will automatically include a prior comparative SUV measurement to demonstrate any change. This is standard practice and not the intent of this measure. Furthermore, at the discretion of physicians in some cases there may not be a good comparison measurement or size changes may be most relevant (and the SUV values may be misleading), so they may choose to not include certain comparative measures.