MRI of the sacroiliac joints in spondyloarthritis: the added value of intra-articular signal changes for a 'positive MRI'.

OBJECTIVE: To determine if intra-articular signal changes at the sacroiliac joint space on MRI have added diagnostic value for spondyloarthritis, when compared to bone marrow edema (BME). MATERIALS AND METHODS: A retrospective study was performed on the MRIs of sacroiliac joints of 363 patients, aged 16-45 years, clinically suspected of sacroiliitis. BME of the sacroiliac joints was correlated to intra-articular sacroiliac joint MR signal changes: high T1 signal, fluid signal, ankylosis and vacuum phenomenon (VP). These MRI findings were correlated with final clinical diagnosis. Sensitivity (SN), specificity (SP), likelihood ratios (LR), predictive values and post-test probabilities were calculated. RESULTS: BME had SN of 68.9%, SP of 74.0% and LR+ of 2.6 for diagnosis of spondyloarthritis. BME in absence of intra-articular signal changes had a lower SN and LR+ for spondyloarthritis (SN = 20.5%, LR+ 1.4). Concomitant BME and high T1 signal (SP = 97.2%, LR + = 10.5), BME and fluid signal (SP = 98.6%, LR + = 10.3) or BME and ankylosis (SP = 100%) had higher SP and LR+ for spondyloarthritis. Concomitant BME and VP had low LR+ for spondyloarthritis (SP = 91%, LR + =0.9). When BME was absent, intra-articular signal changes were less prevalent, but remained highly specific for spondyloarthritis. CONCLUSION: Our results suggest that both periarticular and intra-articular MR signal of the sacroiliac joint should be examined to determine whether an MRI is 'positive' or 'not positive' for sacroiliitis associated with spondyloarthritis.

Forensic age estimation based on development of third molars: a staging technique for magnetic resonance imaging.

BACKGROUND: The development of third molars can be evaluated with medical imaging to estimate age in subadults. The appearance of third molars on magnetic resonance imaging (MRI) differs greatly from that on radiographs. Therefore a specific staging technique is necessary to classify third molar development on MRI and to apply it for age estimation. AIM: To develop a specific staging technique to register third molar development on MRI and to evaluate its performance for age estimation in subadults. MATERIALS AND METHODS: Using 3T MRI in three planes, all third molars were evaluated in 309 healthy Caucasian participants from 14 to 26 years old. According to the appearance of the developing third molars on MRI, descriptive criteria and schematic representations were established to define a specific staging technique. Two observers, with different levels of experience, staged all third molars independently with the developed technique. Intra- and inter-observer agreement were calculated. The data were imported in a Bayesian model for age estimation as described by Fieuws et al. (2016). This approach adequately handles correlation between age indicators and missing age indicators. It was used to calculate a point estimate and a prediction interval of the estimated age. Observed age minus predicted age was calculated, reflecting the error of the estimate. RESULTS: One-hundred and sixty-six third molars were agenetic. Five percent (51/1096) of upper third molars and 7% (70/1044) of lower third molars were not assessable. Kappa for inter-observer agreement ranged from 0.76 to 0.80. For intra-observer agreement kappa ranged from 0.80 to 0.89. However, two stage differences between observers or between staging sessions occurred in up to 2.2% (20/899) of assessments, probably due to a learning effect. Using the Bayesian model for age estimation, a mean absolute error of 2.0 years in females and 1.7 years in males was obtained. Root mean squared error equalled 2.38 years and 2.06 years respectively. The performance to discern minors from adults was better for males than for females, with specificities of 96% and 73% respectively. CONCLUSION: Age estimations based on the proposed staging method for third molars on MRI showed comparable reproducibility and performance as the established methods based on radiographs.

MR signal in the sacroiliac joint space in spondyloarthritis: a new sign.

OBJECTIVES: To determine the diagnostic value of MR signal within the sacroiliac (SI) joint space in spondyloarthritis (SpA). METHODS: A retrospective analysis of MRIs of SI joints was performed in 363 patients, aged 16-45 years, clinically suspected of sacroiliitis. Intra-articular SI joint MR signals were categorized as normal, high T1 signal, fluid signal, ankylosis or vacuum phenomenon (VP). These MRI findings were correlated with the final diagnosis, according to the ASAS criteria. Sensitivity, specificity, and positive and negative likelihood ratios (LR) and predictive values were calculated. RESULTS: Presence of intra-articular high T1 signal, fluid signal and ankylosis had a specificity of 95.8 %, 95.3 % and 99.5 % for SpA. High T1 signal, fluid signal and ankylosis were present in 38.4 %, 19.2 % and 17.9 % of SpA patients and in 4.2 %, 4.7 % and 0.5 % of patients without SpA, resulting in LR+ of 9.0, 4.1 and 37.9, respectively. VP was present in 13.2 % of SpA patients and in 20.8 % of patients without SpA, resulting in an LR+ of 0.6. CONCLUSIONS: Presence of high T1 signal, fluid signal and ankylosis within the SI joint on MRI have high specificity for SpA. High T1 signal is the most sensitive MRI feature within the SI joint for SpA. KEY POINTS: • MRI of the SI joints is typically obtained for diagnosis of spondyloarthritis. • The MR signal within the SI joint itself reflects features of spondyloarthritis. • Intra-articular high T1 signal, fluid signal and ankylosis are seen in spondyloarthritis. • The vacuum phenomenon makes spondyloarthritis less likely.

Diagnositic value of pelvic enthesitis on MRI of the sacroiliac joints in enthesitis related arthritis.

BACKGROUND: To determine the prevalence and diagnostic value of pelvic enthesitis on MRI of the sacroiliac (SI) joints in enthesitis related arthritis (ERA). METHODS: We retrospectively studied 143 patients aged 6-18 years old who underwent MRI of the SI joints for clinically suspected sacroiliitis between 2006-2014. Patients were diagnosed with ERA according to the International League of Associations for Rheumatology (ILAR) criteria. All MRI studies were reassessed for the presence of pelvic enthesitis, which was correlated to the presence of sacroiliitis on MRI and to the final clinical diagnosis. The added value for detection of pelvic enthesitis and fulfilment of criteria for the diagnosis of ERA was studied. RESULTS: Pelvic enthesitis was seen in 23 of 143 (16 %) patients. The most commonly affected sites were the entheses around the hip (35 % of affected entheses) and the retroarticular interosseous ligaments (32 % of affected entheses). MRI showed pelvic enthesitis in 21 % of patients with ERA and in 13 % of patients without ERA. Pelvic enthesitis was seen on MRI in 7/51 (14 %) patients with clinically evident enthesitis, and 16/92 (17 %) patients without clinically evident enthesitis. In 7 of 11 ERA-negative patients without clinical enthesitis but with pelvic enthesitis on MRI, the ILAR criteria could have been fulfilled, if pelvic enthesitis on MRI was included in the criteria. There is a high correlation between pelvic enthesitis and sacroiliitis, with sacroiliitis present in 17/23 (74 %) patients with pelvic enthesitis. CONCLUSIONS: Pelvic enthesitis may be present in children with or without clinically evident peripheral enthesitis. There is a high correlation between pelvic enthesitis and sacroiliitis on MRI of the sacroiliac joints in children. As pelvic enthesitis indicates active inflammation, it may play a role in assessment of the inflammatory status. Therefore, it should be carefully sought and noted by radiologists examining MRI of the sacroiliac joints in children.

Diagnostic value of MRI features of sacroiliitis in juvenile spondyloarthritis.

AIM: To determine the diagnostic utility of magnetic resonance imaging (MRI) features of sacroiliitis in juvenile spondyloarthritis (JSpA). MATERIALS AND METHODS: This was a prospective study of 80 paediatric patients who underwent MRI of the sacroiliac joints that were clinically suspected to have sacroiliitis. The prevalence of MRI features of active and structural lesions of sacroiliitis was recorded. Patients were classified according to the International League of Association for Rheumatology criteria. The MRI findings were compared to the final clinical diagnosis. RESULTS: Sacroiliitis was seen in 25/80 (31%) patients. MRI showed active inflammation in 23 patients (29%): synovial enhancement (28%), high short tau inversion recovery (STIR)-signal in the joint space (29%), bone marrow oedema (BMO; 20%), and capsulitis (8%). Structural changes were present in 14 patients (18%): erosion (14%), fat infiltration (13%), sclerosis (8%), and ankylosis (1%). Of all MRI features, ankylosis (100%), capsulitis (98%), BMO (96%), and erosion (96%) had the highest specificity for JSpA; global diagnostic impression (55%) and synovial enhancement (52%) were the MRI features with the highest sensitivity. The likelihood ratios (LR+) for diagnosis of JSpA were high for BMO (10.5), capsulitis (7.5), global diagnostic impression (6.9), and erosions (6.75), but greater for BMO concomitant with synovial enhancement (LR+ 19.5) and for erosion concomitant with BMO (LR+ 12) or synovial enhancement (LR+ 13.5). CONCLUSION: There are multiple features of active inflammation and structural damage visible at MRI of the sacroiliac joints that can provide a specific diagnosis of JSpA when present in children with suspected sacroiliitis. Synovial enhancement is the MRI feature with the highest sensitivity for JSpA. If BMO is seen concomitant with synovial enhancement or erosion, the diagnosis of JSpA is very likely. Ankylosis, capsulitis, bone marrow oedema, and erosion all have a high specificity for JSpA. Absence of MRI findings of sacroiliitis does not exclude the diagnosis of JSpA.

ISCHIOFEMORAL IMPINGEMENT DUE TO A SOLITARY EXOSTOSIS.

Ischiofemoral impingement is a rare cause of hip pain related to narrowing of the space between the ischial tuberosity and the lesser trochanter. It is usually seen in middle-aged women. We report a rare case of a young male patient presenting with ischiofemoral impingement due to a solitary exostosis at the lesser trochanter. Imaging, especially Magnetic Resonance Imaging (MRI), is an excellent tool to confirm the diagnosis by demonstrating narrowing of the ischiofemoral space and soft tissue edema in the muscle belly of the quadratus femoris muscle.

OSTEOCHONDROMA OF THE PROXIMAL HUMERUS WITH FRICTIONAL BURSITIS AND SECONDARY SYNOVIAL OSTEOCHONDROMATOSIS.

We report a case of multiple hereditary exostosis in a 33-year old patient with clinical symptoms of pain and impression of a growing mass of the left shoulder alerting potential risk of malignant transformation of an osteochondroma. Imaging studies illustrated perilesional bursitis surrounding an osteochondroma of the proximal humerus. Malignant transformation was excluded with MRI. Fragments of the osteochondroma were dislocated in the inflammatory synovial bursa illustrating a case of secondary synovial osteochondromatosis.

Limited role of gadolinium to detect active sacroiliitis on MRI in juvenile spondyloarthritis.

OBJECTIVE: The aim of this study is to determine the added diagnostic value of contrast-enhanced (CE) magnetic resonance imaging (MRI) compared to routine non contrast-enhanced MRI to detect active sacroiliitis in clinically juvenile spondyloarthritis (JSpA). MATERIALS AND METHODS: A total of 80 children clinically suspected for sacroiliitis prospectively underwent MRI of the sacroiliac (SI) joints. Axial and coronal T1-weighted (T1), Short-tau inversion recovery (STIR) and fat-saturated T1-weighted gadolinium-DTPA (Gd) contrast-enhanced (T1/Gd) sequences were obtained. The presence of bone marrow edema (BME), capsulitis, enthesitis, high intra-articular STIR signal, synovial enhancement and a global diagnostic impression of the MRI for diagnosis of sacroiliitis was recorded. RESULTS: STIR and T1/Gd sequences had 100% agreement for depiction of BME, capsulitis and enthesitis. High intra-articular STIR signal was seen in 18/80 (22.5%) patients, 15 (83%) of whom also showed synovial enhancement in the T1/Gd sequence. Sensitivity (SN) and specificity (SP) for a clinical diagnosis of JSpA were similar for high STIR signal (SN = 33%, SP = 85%) and T1/Gd synovial enhancement (SN = 36%, SP = 92%). Positive likelihood ratio (LR+) for JSpA was twice as high for synovial enhancement than high STIR signal (4.5 compared to 2.2). Global diagnostic impression was similar (STIR: SN = 55%, SP = 87%, LR + =4 .2; T1/Gd: SN = 55%, SP = 92%, LR + = 6.9). CONCLUSION: MRI without contrast administration is sufficient to identify bone marrow edema, capsulitis and retroarticular enthesitis as features of active sacroiliitis in juvenile spondyloarthritis. In selected cases when high STIR signal in the joint is the only finding, gadolinium-enhanced images may help to confirm the presence of synovitis.

Direct comparison of conventional radiography and cone-beam CT in small bone and joint trauma.

OBJECTIVE: To compare the diagnostic value of cone-beam computed tomography (CBCT) and conventional radiography (CR) after acute small bone or joint trauma. MATERIALS AND METHODS: Between March 2013 and January 2014, 231 patients with recent small bone or joint trauma underwent CR and subsequent CBCT. CR and CBCT examinations were independently assessed by two readers, blinded to the result of the other modality. The total number of fractures as well as the number of complex fractures were compared, and inter- and intraobserver agreement for CBCT was calculated. In addition, radiation doses and evaluation times for both modalities were noted and statistically compared. RESULTS: Fracture detection on CBCT increased by 35% and 37% for reader 1 and reader 2, respectively, and identification of complex fractures increased by 236% and 185%. Interobserver agreement for CBCT was almost perfect, as was intraobserver agreement for reader 1. The intraobserver agreement for reader 2 was substantial. Radiation doses and evaluation time were significantly higher for CBCT. CONCLUSION: CBCT detects significantly more small bone and joint fractures, in particular complex fractures, than CR. In the majority of cases, the clinical implication of the additionally detected fractures is limited, but in some patients (e.g., fracture-dislocations), the management is significantly influenced by these findings. As the radiation dose for CBCT substantially exceeds that of CR, we suggest adhering to CR as the first-line examination after small bone and joint trauma and keeping CBCT for patients with clinical-radiographic discordance or suspected complex fractures in need of further (preoperative) assessment.

Imaging Findings of the Distal Radio-Ulnar Joint in Trauma.

Traumatic lesions of the distal radio-ulnar joint (DRUJ) occur frequently in conjunction with fractures of the distal radius. They are a common cause of pain and limited range of motion after distal radial fractures. Due to the complex anatomy they are however often ignored or underappreciated. Distal radial fractures and luxations of the DRUJ often disturb the normal curvature of the radial notch and cause damage to the cartilage of this joint. The growth of the radius may be disrupted, resulting in a positive ulnar variance, and possibly give rise to complications such as ulnar abutment and motion restriction. Ulnar styloid fractures - sometimes barely visible on plain film - may give rise to symptomatic bony pseudarthrosis, dislocation and laceration of the tendon of the m. extensor carpi ulnaris and a rare posttraumatic deformity of the ulnar epiphysis. Also the possibility of lesions at the adjacent triangular fibrocartilage complex and the joint capsule should be kept in mind. This paper presents a pictorial review of the complex functional anatomy and pathologic conditions of this joint and emphasises why the DRUJ should be evaluated independently and thoroughly. The merit of each imaging modality is mentioned. A correction article relating to Fig. 2 and Fig. 27 can be found here: http://dx.doi.org/10.5334/jbr-btr.966.

Absent Anterior Cruciate Ligament.

This case report presents the MRI findings of aplasia of the anterior cruciate ligament with associated hypoplasia of the posterior cruciate ligament (Manner type 2). Radiographically the presence of a shallow femoral notch and hypoplastic tibial spines (the so-called "dromedar" sign) can aid in the diagnosis. Operative treatment is often not indicated since the congenital absence of the ACL implies longstanding altered biomechanics to which the knee has well adapted in the majority of cases.

Correction: Imaging Findings of the Distal Radio-Ulnar Joint in Trauma.

This article details a correction to: Mespreuve, M, Vanhoenacker, F and Verstraete, K 2015 Imaging Findings of the Distal Radio-Ulnar Joint in Trauma. Journal of the Belgian Society of Radiology, 99(1), pp. 1-20, DOI: http://dx.doi.org/10.5334/jbr-btr.846.

Lunotriquetral coalition, a normal variant that may rarely cause ulnar sided wrist pain.

Lunotriquetral coalition (LTC), the most frequent and often bilateral type of carpal coalition, is in general considered as asymptomatic. In rare cases - however - fibrocartilaginous LTC may be an uncommon cause of ulnar sided pain in the wrist due to the pseudarthrosis or a post-traumatic disruption of LTC. Two rare cases of symptomatic LTC are presented and the role of MRI is emphasized. MRI shows the pseudarthrosis and may additionally show bone marrow edema and subcortical cysts. In symptomatic cases surgical lunotriquetral fusion may be considered as treatment option.

Mounier-Kuhn Syndrome.

BACKGROUND: A 38-year-old male with no medical history complains about hemoptysis, chest pain, dyspnea on exertion and a cough. He has a history of occasional smoking, but had quitted smoking 1 year previously. There is a normal saturation and normal spirometry. Clinical examination and auscultation are also normal. Because of these complaints CT scan of the thorax was performed. For further diagnostic workup bronchoscopy was performed afterwards.

A rare case of diffuse alveolar hemorrhage following oral amphetamine intake.

Diffuse alveolar hemorrhage (DAH) is a clinical syndrome, which refers to injury to the capillaries, arterioles and venules, leading to red blood cell accumulation in the distal air spaces. It is defined by the clinical triad of hemoptysis, anemia and progressive hypoxemia. Chest radiographs reveal non-specific patchy or diffuse bilateral pulmonary consolidation. Multiple conditions are associated with DAH, of which Wegener's granulomatosis is the most frequent, and underlying disease determines the prognosis and treatment. This case describes DAH as a result of oral amphetamine abuse in a young patient of which the diagnosis was established by laboratory, clinical and radiologic findings. The patient experienced a rapid recovery without significant sequelae.

Diagnostic value of pelvic enthesitis on MRI of the sacroiliac joints in spondyloarthritis.

OBJECTIVE: To determine the prevalence and diagnostic value of pelvic enthesitis on MRI of the sacroiliac (SI) joints in spondyloarthritis (SpA). MATERIALS AND METHODS: A retrospective study in 444 patients aged 17-45 years old with MRI of the SI joints and with clinically suspected sacroiliitis was performed. Patients were classified as having SpA if they fulfilled the Assessment of Spondyloarthritis International Society (ASAS) criteria. Pelvic enthesitis on MRI was correlated with the final diagnosis. Sensitivity, specificity, positive and negative likelihood ratio (LR) and predictive values (PV) of pelvic enthesitis for the diagnosis of SpA were calculated. RESULTS: MRI showed pelvic enthesitis in 24.4 % of patients with SpA and in 7.1 % of patients without SpA. Presence of any enthesitis had sensitivity, specificity, LR+, LR-, PPV and NPV of 24.4 %, 92.9 %, 3.45, 0.81, 69.4 % and 65.2 % for the diagnosis of SpA, respectively. The most commonly affected entheses were the longitudinal ligament insertion (4.5 %), the retroarticular ligaments (4.1 %) and the pubic symphysis (4.1 %). The sites of enthesitis with the highest PPV for SpA were the iliac crest/wing (85.7 %) and the retroarticular ligaments (81.3 %). CONCLUSION: Nearly one fourth of SpA patients with suspected sacroiliitis showed pelvic enthesitis on MRI. Such pelvic enthesitis has a high specificity for the diagnosis of spondyloarthritis. KEY POINTS: • Enthesitis is the primary clinical feature of spondyloarthritis. • Magnetic resonance imaging of the sacroiliac joints can demonstrate pelvic enthesitis. • Pelvic enthesitis has a high specificity for the diagnosis of spondyloarthritis.