The role of dual energy computed tomography in the differentiation of acute gout flares and acute calcium pyrophosphate crystal arthritis

Abstract

Objectives To analyse the diagnostic impact of dual energy computed tomography (DECT) in acute gout flares and acute calcium pyrophosphate (CPP) crystal arthritis when compared to the gold standard of arthrocentesis with compensated polarised light microscopy. Microscopy results were also compared to musculoskeletal ultrasound (MUS), conventional radiographs, and the suspected clinical diagnosis (SCD). Methods Thirty-six patients with a suspected gout flare (n = 24) or acute CPP crystal arthritis (n = 11, n = 1 suffered from neither) who received a DECT and underwent arthrocentesis were included. Two independent readers assessed DECT images for signs of monosodium urate crystals or calcium pyrophosphate deposition. Results Sensitivity of DECT for gout was 63% (95% CI 0.41–0.81) with a specificity of 92% (0.41–0.81) while sensitivity and specificity for acute CPP arthritis were 55% (0.23–0.83) and 92% (0.74–0.99), respectively. MUS had the highest sensitivity of all imaging modalities with 92% (0.73–0.99) and a specificity of 83% (0.52–0.98) for gout, while sensitivity and specificity for acute CPP crystal arthritis were 91% (0.59–1.00) and 92% (0.74–0.99), respectively. Conclusion DECT is an adequate non-invasive diagnostic tool for acute gout flares but might have a lower sensitivity than described by previous studies. Both MUS and SCD had higher sensitivities than DECT for acute gout flares and acute CPP crystal arthritis. Key Points• DECT offers a lower sensitivity for acute gout flares than previously described.• DECT sensitivity for acute CPP crystal arthritis is less than the already validated ultrasound.

Systematic literature review to inform the EULAR recommendations for the use of imaging in crystal-induced arthropathies in clinical practice

“…Among studies assessing the diagnostic capacity of DECT for the diagnosis of gout, 21/28 (75%)6 18 19 21–38 and 21/28 (75%)6 18 19 21–24 26 29–31 33–36 38–43 reported sensitivity and specificity, respectively of ≥80%. The sensitivity ranged from 52.8% to 100.0%, the specificity from 50.0% to 100.0%.…”

“…Three out of these five studies (60%)6 38 41 found numerically lower sensitivity (35.7% vs 92.9%, 38.0% vs 77.6% and 55% vs 81%) with similar specificity in the group with shorter disease duration of 1 year or less while two studies (40%)31 44 found no difference between the subgroup with a shorter disease duration and the overall cohort. In 16/28 (57.1%) studies performing DECT, only the (previously) symptomatic side was assessed,18 19 22 26–28 33 37–41 43–46 in 5/28 (17.9%) studies, a predefined set of joints was assessed21 24 25 29 34 and in the remaining 1/28 study (3.6%), the (most) symptomatic joint or recently symptomatic joint as well as the contralateral metatarsophalangeal one joint was assessed 42. The remaining studies23 30–32 35 47 were meta-analyses without data on the assessed joints.…”

“…Of the 23 included studies reporting on the diagnostic value of US in the detection of gout, 16 (69.6%)20 23 28 29 31 32 34 40 48–55 reported on overall diagnosis, while several studies reported (additionally) on the diagnostic value of specific findings: 17 (73.9%) on double contour (DC) sign,31 32 34 45 48–54 56–61 15 (65.2%) tophi,20 31 32 34 48 49 51–54 56 57 59–61 11 (47.8%) aggregates,20 32 45 48 49 51–54 56 57 5 (21.7%) erosions20 48 51 56 57 and 3 (13.0%)20 53 56 inflammation. Only affected joint(s) were assessed in 12/23 (52.2%) studies,20 28 34 40 45 48 50 52 53 57 60–62 while 2/23 (8.7%) studies49 55 assessed the symptomatic site as well as additional joints and in 5 studies29 34 56 58 59 a predefined set of sites was assessed. The remaining four studies23 31 32 51 were meta-analyses.…”

Gouty Arthropathy: Review of Clinical Manifestations and Treatment, with Emphasis on Imaging

“…The presence of tophi on imaging suggests gouty arthropathy rather than an infectious or inflammatory arthropathy. Imaging, particularly DECT, can help differentiate acute calcium pyrophosphate arthropathy from gouty arthropathy, although a recent study showed that DECT may have a lower sensitivity for acute gout flares than previously described, and that DECT sensitivity for acute calcium pyrophosphate crystal arthritis is lower than that of US [ 60 ].…”

Rheumatologische Patienten in der Notaufnahme – Notfälle und Management

“…Diese Methode erlaubt eine Abgrenzung von Natriumurat-Kristallen gegenüber ihrer Umgebung in der CT-Bildgebung und eine farbkodierte Darstellung zur Befundung (▶ Abb. 5)[7]. Die konventionelle Röntgenaufnahme als weiteres bildgebendes Verfahren präsentiert sich im akuten Gichtanfall meist unauffällig und kommt in erster Linie zur Differenzialdiagnostik oder bei chronischer Gicht zur Darstellung von Gelenkerosionen oder röntgendichter Uratablagerungen (Tophi) infrage.Sofern dem Patienten (z.…”