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Purpose: Our aim was to analyze the prevalence of occult destructive arthropathy in subjects with gout and normal x-rays by utilizing MRI and Ultrasound (US).
Methods: All subjects were diagnosed with gout either by i) the presence of monosodium urate (MSU) crystals in the joint fluid or ii) fulfilling at least 6 of the 12 diagnostic criteria. The study consisted of two visits. At visit #1, standard demographics, bloodwork, and an x-ray of the “index joint” were obtained. The “index joint” was defined as that joint which has had the most acute attacks of gout historically. The index joint x-ray was assessed independently by two readers; both readers had to agree that there was no evidence of erosive damage in order for the subject to qualify for visit #2. At visit #2, the subject had an MRI (1.5 Tesla) with contrast and an US (8 MHz) of the index joint. Each subject also had an MRI and US of an “asymptomatic joint” (defined as a joint that had never experienced an attack of gout [determined by standard protocol]). The primary endpoint was erosive changes on the MRI and/or US of the index joint. Secondary endpoints included erosive changes on the asymptomatic joint; as well as bone marrow edema (BME), synovial pannus (SP), soft tissue tophi (STT) or edema (STE) on either the index or asymptomatic joint.
Results: 27 subjects (26 M; 1 F) completed both visits. Their average age and disease duration were 55.1 years (range 21 - 75) and 6.8 years (range 0.25 - 25 years), respectively. 8 subjects (30%) had documented MSU crystals and the other 19 met at least 6 of the 12 diagnostic criteria for gout. The average number of total attacks of gout was 13.48 (range 1 - 41) and those involving the index joint was 6.2 (range 1 - 20). The subjects average serum uric acid level over the past 5 years was 8.1mg/dL (range 4.1 - 12.8); their average on the day of visit #1 was 8.0mg/dL (range 4.6 - 13.9). The 1st metatarsalphalangeal (MTP) was the most common index joint (17) followed by the ankle (5), midtarsal (2), knee (2), and wrist (1). The knee was the most common asymptomatic joint (21) followed by the wrist (3), MTP (2), ankle (1). All subjects had both MRI’s; one subject refused the US. 16/27 subjects (60%) had erosions on MRI of their index joint (p < 0.0001); only 1 subject (4%) had erosions identified in the index joint by US (p = ns). Regarding the secondary endpoints on the index joint, the MRI detected SP (16), BME (5), STE (3), STT (0); the US detected SP (3), STT (1), BME (0), and STE (0). Regarding the MRI of the asymptomatic joint, positive findings included SP (4), BME (3), STE (2); US of this joint revealed SP (1).
Conclusions: A large percentage of patients with gout and normal x-rays have occult destructive arthropathy that is only detected by advanced imaging such as MRI and/or US. However, MRI appears to be much more sensitive than US at detecting these findings.
Methods: All subjects were diagnosed with gout either by i) the presence of monosodium urate (MSU) crystals in the joint fluid or ii) fulfilling at least 6 of the 12 diagnostic criteria. The study consisted of two visits. At visit #1, standard demographics, bloodwork, and an x-ray of the “index joint” were obtained. The “index joint” was defined as that joint which has had the most acute attacks of gout historically. The index joint x-ray was assessed independently by two readers; both readers had to agree that there was no evidence of erosive damage in order for the subject to qualify for visit #2. At visit #2, the subject had an MRI (1.5 Tesla) with contrast and an US (8 MHz) of the index joint. Each subject also had an MRI and US of an “asymptomatic joint” (defined as a joint that had never experienced an attack of gout [determined by standard protocol]). The primary endpoint was erosive changes on the MRI and/or US of the index joint. Secondary endpoints included erosive changes on the asymptomatic joint; as well as bone marrow edema (BME), synovial pannus (SP), soft tissue tophi (STT) or edema (STE) on either the index or asymptomatic joint.
Results: 27 subjects (26 M; 1 F) completed both visits. Their average age and disease duration were 55.1 years (range 21 - 75) and 6.8 years (range 0.25 - 25 years), respectively. 8 subjects (30%) had documented MSU crystals and the other 19 met at least 6 of the 12 diagnostic criteria for gout. The average number of total attacks of gout was 13.48 (range 1 - 41) and those involving the index joint was 6.2 (range 1 - 20). The subjects average serum uric acid level over the past 5 years was 8.1mg/dL (range 4.1 - 12.8); their average on the day of visit #1 was 8.0mg/dL (range 4.6 - 13.9). The 1st metatarsalphalangeal (MTP) was the most common index joint (17) followed by the ankle (5), midtarsal (2), knee (2), and wrist (1). The knee was the most common asymptomatic joint (21) followed by the wrist (3), MTP (2), ankle (1). All subjects had both MRI’s; one subject refused the US. 16/27 subjects (60%) had erosions on MRI of their index joint (p < 0.0001); only 1 subject (4%) had erosions identified in the index joint by US (p = ns). Regarding the secondary endpoints on the index joint, the MRI detected SP (16), BME (5), STE (3), STT (0); the US detected SP (3), STT (1), BME (0), and STE (0). Regarding the MRI of the asymptomatic joint, positive findings included SP (4), BME (3), STE (2); US of this joint revealed SP (1).
Conclusions: A large percentage of patients with gout and normal x-rays have occult destructive arthropathy that is only detected by advanced imaging such as MRI and/or US. However, MRI appears to be much more sensitive than US at detecting these findings.
J.D. Carter, Takeda Pharmaceuticals; R.P. Kedar, None; A.H. Osorio, None; N.L. Albritton, None; S. Gnanashanmugam, None; J. Valeriano, None; F.B. Vasey, None; L. Ricca, None.