Dynamic assessment of the double contour sign by ultrasonography helps to distinguish between gout and calcium pyrophosphate deposition disease.

OBJECTIVE: To test whether the double contour (DC) sign has a different dynamic behaviour in gout and calcium pyrophosphate deposition (CPPD) and whether the dynamic assessment of the DC sign increases its accuracy in gout diagnosis. METHODS: This cross-sectional analysis included patients with gout meeting the 2015 ACR/EULAR classification criteria and patients with crystal-proven diagnosis of CPPD. Hyaline cartilages were explored by ultrasound (US) to detect the DC sign (ie, abnormal hyperechoic band over the superficial margin of hyaline cartilages) and its dynamic behaviour during joint movement was evaluated ((ie, movement of the DC sign together with subchondral bone (DC sign), or in the opposite direction (pseudo DC sign)). RESULTS: Eighty-one patients with gout and 84 patients with CPPD underwent US assessment. Among them, 47 patients with gout and 9 patients with CPPD had evidence of the DC sign. During dynamic assessment, in all 47/47 patients with gout there was a DC sign. Conversely, in 7/9 (77.8%) patients with CPPD, there was a pseudo DC sign (p<0.01).The presence of DC sign during static assessment had a sensitivity, specificity and accuracy of 58.0% (95% CI 46.5% to 68.9%), 89.3% (95% CI 80.6% to 95.0%) and 73.9% (95% CI 66.5% to 80.5%) for gout, respectively. The dynamic evaluation improved the DC sign's diagnostic performance (p=0.01) as the specificity (97.6% (95% CI 91.7% to 99.7%)) and the accuracy (78.2% (95% CI 71.1% to 84.2%)) increased without loss in sensitivity. CONCLUSION: The dynamic US assessment of the DC sign may help to differentiate the DC sign due to MSU crystals from the pseudo DC sign seen in CPPD, as they move in opposite directions.

Sonographic assessment of calcium pyrophosphate deposition disease at wrist. A focus on the dorsal scapho-lunate ligament.

OBJECTIVES: To investigate the diagnostic accuracy of ultrasound and conventional radiography in the evaluation of calcium pyrophosphate crystal deposits at wrist level. METHODS: Consecutive patients with a "definite" diagnosis of calcium pyrophosphate deposition disease and disease-controls were prospectively included in this cross-sectional single-centre study. Scapho-lunate ligament, triangular fibrocartilage complex, and volar recess of the radio-lunate joint were explored using ultrasound, conventional radiography and computed tomography. RESULTS: Sixty one patients and 39 disease controls were enrolled. Two-hundred wrists were evaluated using both conventional radiography and ultrasound and 26 using computed tomography. Ultrasound findings indicative of crystal deposits were found in at least one wrist in 95.1% of patients and in 15.4% of controls (P<0.001). Scapho-lunate ligament calcifications were reported in 83.6% of patients and in 5.1% of controls (P<0.001). On conventional radiography, calcifications were found in at least one wrist in 72.1% of patients and in 0% of controls (P<0.001). Using the Ryan-McCarty criteria as a gold standard, sensitivity, specificity and diagnostic accuracy were 0.72 (0.59-0.83), 1.0 (0.91-1.0) and 0.83 (0.74-0.90) for conventional radiography and 0.95 (0.86-0.99), 0.85 (0.69-0.94) and 0.91 (0.84-0.96) for ultrasound. The agreement between ultrasound and computed tomography was substantial when assessing triangular fibrocartilage complex (kappa=0.70; 0.43-0.97) and scapho-lunate ligament (kappa=0.69; 0.41-0.97), and moderate for radio-lunate joint (kappa=0.46; 0.12-0.80). CONCLUSIONS: This study supports the diagnostic accuracy of ultrasound in evaluating wrist involvement in calcium pyrophosphate deposition disease. The inclusion of the scapho-lunate ligament in a disease-oriented scanning protocol could improve the diagnostic performance of ultrasound.

Diagnostic accuracy of musculoskeletal ultrasound and conventional radiography in the assessment of the wrist triangular fibrocartilage complex in patients with definite diagnosis of calcium pyrophosphate dihydrate deposition disease.

OBJECTIVES: To compare the diagnostic accuracy of musculoskeletal ultrasound (MSUS) and x-ray in evaluating wrist triangular fibrocartilage complex (TFCC) in patients with calcium pyrophosphate dihydrate deposition disease (CPPD) and to investigate the agreement between the extent of the calcium pyrophosphate dihydrate (CPP) crystal deposits assessed by MSUS and the radiographic findings. METHODS: We enrolled 84 patients: 36 patients with "definite" CPPD and 48 controls. The Ryan and McCarty diagnostic criteria were used. A rheumatologist performed bilateral MSUS examinations of the TFCC in all patients, assessing both the presence and absence of CCP crystals deposits and their extent (0-3; 0: absent; 1: 1-2 spots; 2: more than two spots covering <50% of the volume of the structure; 3: deposits covering >50% of the volume of the structure). A radiologist evaluated the presence/absence of x-ray calcifications at TFCC level in both groups. RESULTS: MSUS and x-ray sensitivity was 77.8% and 76.4%, respectively, whereas MSUS and x-ray specificity was 90.6% and 96.9%, respectively. Total agreement between MSUS and radiographic findings indicative of calcifications at TFCC level was 88.7%. CONCLUSIONS: This study supports the diagnostic accuracy of MSUS and x-ray in evaluating TFCC crystal deposits in patients with CPPD. Sensitivity and specificity of MSUS and x-ray resulted comparable. The highest MSUS score of the extent of the deposits correlated better with x-ray findings.

Definition and Reliability Assessment of Elementary Ultrasonographic Findings in Calcium Pyrophosphate Deposition Disease: A Study by the OMERACT Calcium Pyrophosphate Deposition Disease Ultrasound Subtask Force.

OBJECTIVE: To define the ultrasonographic characteristics of calcium pyrophosphate crystal (CPP) deposits in joints and periarticular tissues and to evaluate the intra- and interobserver reliability of expert ultrasonographers in the assessment of CPP deposition disease (CPPD) according to the new definitions. METHODS: After a systematic literature review, a Delphi survey was circulated among a group of expert ultrasonographers, who were members of the CPPD Ultrasound (US) Outcome Measures in Rheumatology (OMERACT) subtask force, to obtain definitions of the US characteristics of CPPD at the level of fibrocartilage (FC), hyaline cartilage (HC), tendon, and synovial fluid (SF). Subsequently, the reliability of US in assessing CPPD at knee and wrist levels according to the agreed definitions was tested in static images and in patients with CPPD. Cohen's κ was used for statistical analysis. RESULTS: HC and FC of the knee yielded the highest interobserver κ values among all the structures examined, in both the Web-based (0.73 for HC and 0.58 for FC) and patient-based exercises (0.55 for the HC and 0.64 for the FC). Kappa values for the other structures were lower, ranging from 0.28 in tendons to 0.50 in SF in the static exercise and from 0.09 (proximal patellar tendon) to 0.27 (triangular FC of the wrist) in the patient-based exercise. CONCLUSION: The new OMERACT definitions for the US identification of CPPD proved to be reliable at the level of the HC and FC of the knee. Further studies are needed to better define the US characteristics of CPPD and optimize the scanning technique in other anatomical sites.

Ultrasound imaging for the rheumatologist. XXV. Sonographic assessment of the knee in patients with gout and calcium pyrophosphate deposition disease.

The knee is a frequent target for gout and calcium pyrophosphate dihydrate (CPPD) disease with involvement of both articular and peri-articular structures. The aims of the present study were to investigate the relationship between clinical and ultrasound (US) findings and to describe the prevalence and distribution of crystal deposits in the knee in patients with gout and CPPD disease. Thirty patients with gout and 70 patients with CPPD disease were enrolled in the study. Prior to US assessment all patients underwent a clinical examination by an expert rheumatologist who recorded the presence/absence of pain, tenderness (evocated by palpation and/or active or passive mobilisation of the knee), and knee swelling. US examinations were performed using a Logiq 9 (General Electric Medical Systems, Milwaukee, WI) equipped with a multifrequency linear probe, working at 9 MHz. Two hundred knee joints were investigated in a total of 100 patients. Fifty-one (25.5%) knee joints were found clinically involved, while at least one US finding indicative of joint inflammation was obtained in 73 (36.5%) knee joints.The most frequent US finding indicative of knee joint inflammation was joint effusion, detected in 21 (35%) out of 60 knees and in 52 (37%) out of 140 knees, in gout and CPPD disease, respectively. Ten (17%) out of 60 knees and 21 (15%) out of 140 knees were found positive for synovial hypertrophy with or without intra-articular power Doppler, in gout and CPPD disease respectively. Sonographic evidence of crystal deposition within joint cartilage (hyaline and fibrocartilage) was more frequently seen than in the soft tissue in the knee.This study demonstrated that US detected a higher number of inflamed knee joints than clinical assessment in patients with crystal related arthropathies and that the distribution of crystal deposits at joint cartilage level permitted distinction between gout and CPPD disease. Further studies are required to investigate both sensitivity and specificity of US features indicative of crystal aggregates at both tendon and entheseal level.

[The current role of ultrasound in the assessment of crystal-related arthropathies]. / Il ruolo attuale dell'ecografia nelle artropatie da microcristalli.

Over last few years, the ultrasonography (US) generated an increasing popularity among rheumatologists due to excellent potentiality and numerous applications in rheumatology. Most of the published papers focus mainly to demonstrate the utility of US in early and chronic arthritis, short-term therapy monitoring and guidance for invasive procedures. Less attention has been paid to the potential of this technique in the field of crystal-related arthropathies. By virtue of the high resolution of "new generation" equipments, minimal crystal deposits can be detected even sometime when the radiography was negative. The aim of this paper was to present the principal findings in patients with crystal-related arthropathies.

"Crystal clear"-sonographic assessment of gout and calcium pyrophosphate deposition disease.

OBJECTIVES: To date, high-resolution ultrasound (US) has not been fully exploited in the field of crystalline arthropathy. Both gout and calcium pyrophosphate deposition (CPPD) disease are significant diseases within the purview of the rheumatologist. The aim of this pictorial review was to present the principal findings in patients with crystal deposition in gout and CPPD. METHODS: US pictures were obtained from 60 consecutive patients, 34 with CPPD disease and 26 with gout, whose diagnosis was confirmed by synovial fluid analysis. The US examinations were performed using the following US systems: Diasus (Dynamic Imaging, Livingstone, UK) and Logiq 9 (General Electric Medical Systems, Milwaukee, WI). RESULTS: Pictorial evidence of the principal US findings in gout includes monosodium urate (MSU) deposition on the surface of articular cartilage, various patterns within synovial fluid ranging from completely anechoic fluid to collections filled with aggregates of variable shape and echogenicity, microdeposition within tendons, and tophus formation. In CPPD, the hallmark US features include crystal deposition within articular cartilage, calcification of fibrocartilage, together with focal crystal deposition within tendons. CONCLUSION: US is an impressive imaging modality in crystalline arthropathy. The anatomical location of the crystal deposits, clearly depictable by US, allows differentiation between MSU and CPPD aggregates.

Xeroradiographic techniques applied to assessment of Achilles tendon in inflammatory or metabolic diseases.

Ten patients with inflammatory disease (rheumatoid arthritis, ankylosing spondylitis, Reiter's disease) or metabolic disease (gout, pseudogout, tendinous xanthomatosis) affecting the Achilles tendons are presented and discussed. Radiological lateral views of heel were obtained with xeroradiographic techniques, which permitted the recording on the same image of details of both bone and soft tissue and the evaluation and quantification of the changes in the Achilles tendons. Xeroradiography seems to be a very suitable radiological technique for routine use in the evaluation and follow up of rheumatic diseases of the foot.