Fluorodeoxyglucose positron emission tomography/computed tomography: a “one stop shop” for diagnosing polymyalgia rheumaticaBMJ 2014; 348 doi: https://doi.org/10.1136/bmj.f7705 (Published 06 January 2014) Cite this as: BMJ 2014;348:f7705
- Michael S Hofman, physician in nuclear medicine and molecular imaging1
In their clinical review Mackie and Mallen highlight that the diagnosis of polymyalgia rheumatica can be challenging and dependent on clinical experience and expertise, underscoring the need for better diagnostic algorithms.1 Given the various differential diagnoses, including occult infection, cancer, and myositis, patients are often subjected to an array of investigations before the diagnosis is established (often by exclusion), resulting in delayed diagnosis and costs associated with misdirected investigations.
Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) enables whole body imaging of glycolytic metabolism and is widely used for cancer imaging.2 Acute and chronic inflammatory processes also use glycolytic metabolism, making this technique extremely useful for imaging inflammatory diseases. It essentially enables “imaging of erythrocyte sedimentation rate” defining the location, pattern, and degree of inflammation.
Scans in polymyalgia rheumatica have a characteristic appearance (figure⇓), with visualisation of distinctive interspinous bursitis, widespread enthesopathy, synovitis, and background vasculitis of large or medium large vessels.3 4 PET/CT has specific patterns for the differential diagnoses including infection, cancer, and myositis, thereby providing a “one stop shop” for diagnosis.
Although FDG PET/CT is perceived as expensive, use of an accurate and high yield test upfront can pinpoint the appropriate investigations to be performed. This can prove more cost effective than performing an array of non-specific tests, which can lead to incorrect diagnosis and misdirected patient management. PET also provides more accurate and earlier assessment of response because glycolytic activity dissipates rapidly with effective treatment. The time has come for rheumatologists to embrace this technology to improve patient outcomes.
Cite this as: BMJ 2014;348:f7705
Competing interests: None declared.