Correlation of intra-articular bleeding using Tc-99m RBC scintigraphy with synovial thickness measured on ultrasound in haemophiliac arthropathy

Objectives: Haemophiliac arthropathy is debilitating joint condition due to repeated intra-articular bleeding. The synovial membrane proliferates and thickens due to repeated bleeding causing arthropathy. In advanced stages synovium may undergo atrophy. The synovial thickness is well studied on ultrasound.(1-4) The purpose of the study was to correlate intra-articular bleeding on Tc-99m RBC and synovial thickness on the Ultrasound.

Methods: 84 joints(48 knees, 24 elbows, 9 ankles, 2 shoulders and one interphalangeal joint of foot) in 40 haemophiliac patients (age 8-37 yrs) with repeated intra-articular bleeding were included. Target joint was defined as a recurrently bleeding joint with at least 蠅 3 clinically detected bleeding episodes in 6 months. Mean 370MBq of Tc-99m RBC using in vivo method of labelling was injected intravenously. Perfusion of target joint and delayed static images of all joints were acquired. The findings of Tc-99m RBC study was divided in three groups as no intra-articular bleeding with normal perfusion, increased perfusion with no intra-articular bleeding and increased perfusion with intra-articular bleeding. The ultrasound for target joints was done to assess the mean synovial membrane thickness and intra-articular collection of fluid. For the purpose of this study; the synovial thickness was grades as grade I (≤ 3mm) and grade II (>3mm) based on synovial thickness. (1) Three groups assessed on Tc-99m RBC scan were compared with synovial thickness on ultrasound, no of bleeding episodes in last 6 months and Pettersson joint score on X ray. (5)

Results: No intra-articular bleeding or increased perfusion was noted in 23 joints on Tc-99m RBC scintigraphy and 87% of these joints had grade I (≤ 3mm) synovial thickness. 27/39 (69%) joints showed increased perfusion and intra-articular bleeding on Tc-99m RBC scintigraphy had grade II (>3mm) thickness of synovium. The grade II (>3mm) thickness of synovium was associated with more incidence of bleeding (p=0.0062). However possibility of active bleeding was demonstrated better as evident on Tc-99m RBC scan when compared to ultrasound in grade I (≤ 3mm) thickness of synovium. Tc-99m RBC scan finding correlated well with the number of clinical bleeding episodes 6 months prior to the study (p=0.001). There was evidence of more bleeding episodes noted with advanced grade of arthritis as seen on Pettersson radiological scoring (p=0.04). Tc-99m RBC scan revealed increased perfusion and intra-articular bleeding in 25% patients in additional joints; that did not have history of clinically evident bleed as reported by the patient.

Conclusion: Tc-99m RBC scan scored better in demonstrating intra-articular bleeding with grade I (≤ 3mm) and grade II (>3mm) thickening of synovium. The higher grade of arthropathy demonstrated more bleeding episodes. Tc-99m RBC scan detected bleeding in joints before it was clinically evident in 25% patients. Research Support: nil

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