Arthrosonographie: Langzeitbeurteilung und Inter-reader-Reliabilität am Beispiel der rheumatoiden Arthritis

Abstract

Die Promotionsarbeit hat die Auswertung zweier Studien zum Inhalt. Die erste Studie (Studie 1) stellt eine vergleichende Langzeitverlaufsuntersuchung über einen Zeitraum von sieben Jahren dar, die systematisch die Aussagefähigkeit der Arthrosonographie-Methode im Vergleich zu laborchemischen (CRP, BSG), klinischen (druckschmerzhafte/geschwollene Gelenke) und anderen bildgebenden Verfahren (konventionelles Röntgen, MRT) ermittelt. In diese Studie sind 16 Patienten mit einer rheumatoiden Arthritis (RA) eingeschlossen worden, deren radiologischer Verlauf unter einer konstanten Basistherapie mit DMARDs ermittelt wird, insbesondere unter dem Gesichtspunkt der Entwicklung von initial per US und MRT detektierten Erosionen, die sieben Jahre später im Röntgen gesehen werden. Die zweite Studie (Studie 2) ist eine Reliabilitätsstudie, die die Übereinstimmung zwischen unterschiedlich erfahrenen Untersuchern (zehn Jahre US-Erfahrung vs. zehn Monate bzw. einen Monat US-Erfahrung) in der arthrosonographischen Beurteilung typischer RA- Pathologien von Finger-, Schulter-, Knie- und Sprunggelenken untersucht. Sie hat damit zum Ziel, die als sehr untersucherabhängig geltende Methode des Gelenkultraschalls zu überprüfen. In dieser Studie wird außerdem die wachsende Kompetenz des US-Anfängers anhand einer Lernkurve in Abhängigkeit zur Anzahl der Untersuchungszyklen ermittelt.

Studie 1 Abstract OBJECTIVE: To perform a prospective long term follow up study comparing conventional radiography (CR), ultrasonography (US), and magnetic resonance imaging (MRI) in the detection of bone erosions and synovitis in rheumatoid arthritis (RA) finger joints. METHODS: The metacarpophalangeal and proximal interphalangeal joints II-V (128 joints) of the clinically dominant hand of 16 patients with RA were included. Follow up joint by joint comparisons for erosions and synovitis were made. RESULTS: At baseline, CR detected erosions in 5/128 (4 %) of all joints, US in 12/128 (9 %), and MRI in 34/128 (27 %). Seven years later, an increase of joints with erosions was found with CR (26 %), US (49 %) (p < 0.001 each), and MRI (32 %, NS). In contrast, joint swelling and tenderness assessed by clinical examination were decreased at follow up (p = 0.2, p < 0.001). A significant reduction in synovitis with US and MRI (p < 0.001 each) was seen. In CR, 12 patients did not have any erosions at baseline, while in 10/12 patients erosions were detected in 25/96 (26 %) joints after 7 years. US initially detected erosions in 9 joints, of which two of these joints with erosions were seen by CR at follow up. MRI initially found 34 erosions, of which 14 (41 %) were then detected by CR. CONCLUSION: After 7 years, an increase of bone erosions was detected by all imaging modalities. In contrast, clinical improvement and regression of synovitis were seen only with US and MRI. More than one third of erosions previously detected by MRI were seen by CR 7 years later. Studie 2 Abstract OBJECTIVE: To assess interreader agreements and a learning curve between three (senior, junior and beginner) musculoskeletal ultrasonographers with different experience. Senior served as the imaging “gold standard”. METHODS: Clinically dominant joints (finger, shoulder, knee, tibiotalar, talonavicular) of 15 rheumatoid arthritis (RA) patients were examined by three differently experienced ultrasonographers (senior 10 years, junior 10 months, beginner one month experience). Each patient’s ultrasonographical findings were reported unaware of the other investigators’ results. The junior’s and beginner’s results were compared with the senior’s results using κ coefficients, overall agreements, sensitivities and specificities. RESULTS: 120 joints of 15 RA patients were evaluated. Comparing junior’s and beginner’s results each to the senior’s findings, the overall κ for all examined joints was 0.83 (93 %) for junior and 0.43 (76 %) for beginner. If the focus is on different joint regions, junior’s findings agreed very well with the senior’s findings (finger joints:  = 0.82; shoulder:  = 0.9; knee:  = 0.74; tibiotalar joint:  = 0.84; talonavicular joint:  = 0.84) while beginner’s findings showed moderate agreements (finger joints:  = 0.4; shoulder:  = 0.42; knee:  = 0.4; tibiotalar joint:  = 0.59; talonavicular joint:  = 0.35). Junior reached perfect κ = 1 in detecting rotator cuff rupture and baker’s cyst. In total, beginner’s results clearly improved from κ = 0.34 (agreement of 67 %) at baseline to κ = 0.78 (agreement of 89 %) at the end of the evaluation period. CONCLUSION: Ultrasonographical evaluation of a ten months experienced investigator in comparison to a senior ultrasonographer was of substantial agreement. Agreements between a beginner and a highly experienced ultrasonographer were only moderate at the beginning but during the study period including ultrasonographical sessions of 15 patients with RA the beginner clearly improved in musculoskeletal ultrasonography.