Jean-Luc Drapé

Diagnostic Imaging of Solitary Tumors of the Spine: What to Do and Say

Metastatic disease, myeloma, and lymphoma are the most common malignant spinal tumors. Hemangioma is the most common benign tumor of the spine. Other primary osseous lesions of the spine are more unusual but may exhibit characteristic imaging features that can help the radiologist develop a differential diagnosis. Radiologic evaluation of a patient who presents with osseous vertebral lesions often includes radiography, computed tomography (CT), and magnetic resonance (MR) imaging. Because of the complex anatomy of the vertebrae, CT is more useful than conventional radiography for evaluating lesion location and analyzing bone destruction and condensation. The diagnosis of spinal tumors is based on patient age, topographic features of the tumor, and lesion pattern as seen at CT and MR imaging. A systematic approach is useful for recognizing tumors of the spine with characteristic features such as bone island, osteoid osteoma, osteochondroma, chondrosarcoma, vertebral angioma, and aneurysmal bone cyst. In the remaining cases, the differential diagnosis may include other primary spinal tumors, vertebral metastases and major nontumoral lesions simulating a vertebral tumor, Paget disease, spondylitis, echinococcal infection, and aseptic osteitis. In many cases, vertebral biopsy is warranted to guide treatment.

Virtual Monochromatic Spectral Imaging with Fast Kilovoltage Switching: Reduction of Metal Artifacts at CT

With arthroplasty being increasingly used to relieve joint pain, imaging of patients with metal implants can represent a significant part of the clinical work load in the radiologists daily practice. Computed tomography (CT) plays an important role in the postoperative evaluation of patients who are suspected of having metal prosthesis-related problems such as aseptic loosening, bone resorption or osteolysis, infection, dislocation, metal hardware failure, or periprosthetic bone fracture. Despite advances in detector technology and computer software, artifacts from metal implants can seriously degrade the quality of CT images, sometimes to the point of making them diagnostically unusable. Several factors may help reduce the number and severity of artifacts at multidetector CT, including decreasing the detector collimation and pitch, increasing the kilovolt peak and tube charge, and using appropriate reconstruction algorithms and section thickness. More recently, dual-energy CT has been proposed as a means of reducing beam-hardening artifacts. The use of dual-energy CT scanners allows the synthesis of virtual monochromatic spectral (VMS) images. Monochromatic images depict how the imaged object would look if the x-ray source produced x-ray photons at only a single energy level. For this reason, VMS imaging is expected to provide improved image quality by reducing beam-hardening artifacts.

Variability in knee radiographing: implication for definition of radiological progression in medial knee osteoarthritis

OBJECTIVES (1) To assess reproducibility of medial knee joint space width (JSW) measurement in healthy subjects and osteoarthritic (OA) patients. (2) To define minimal relevant radiological change in knee JSW based on the reproducibility of its measurement. PATIENTS AND METHODS (1) Healthy volunteers: in the first part of the study, 20 knees of healthy adult volunteers were radiographed in the weightbearing, anteroposterior extended view, twice, two weeks apart, using three different radiographic procedures: (a) without guidelines, (b) with guidelines and without fluoroscopy, (c) with guidelines and fluroroscopy. (2) Knee OA patients: in the second part of the study, 36 knees of OA patients were radiographed twice with guidelines and without fluoroscopy. JSW was measured blindly using a graduated magnifying glass. Based on the Bland and Altman graphic approach, cut off points defining minimal relevant radiological change are proposed. RESULTS Standard deviation (SD) of differences in JSW measurement between two sets of knee radiographs in healthy subjects were 0.66 mm for radiography performed without guidelines, 0.37 mm for radiography performed with guidelines and without fluoroscopy, and 0.31 mm for radiography with guidelines and fluoroscopy. SD of differences in JSW measurement in OA patients were 0.32 mm for radiography performed with guidelines and without fluoroscopy. A minimal relevant change in JSW between two radiographs performed in healthy subjects can be defined by a change of at least 1.29 or 0.59 mm when radiographs are taken without guidelines, and with guidelines and fluoroscopy, respectively. When radiographs are taken with guidelines and without fluoroscopy, the change must be at least 0.73 mm. A similar figure, 0.64 mm was observed in knee OA patients. CONCLUSION Definition of radiological progression varies greatly according to the radiographic procedure chosen. Use of guidelines reduces the threshold of progression required to consider that change between two measures is relevant.

Sonographic Appearance of Trigger Fingers

Objective. The purpose of this study was to describe the sonographic appearance of the first annular (A1) pulley–flexor tendon complex in patients with trigger fingers. Methods. Thirty‐three trigger fingers in 33 patients were examined with a 7‐ to 15‐MHz probe. A control group consisted of 20 patients without trigger fingers. The study included systematic measurement of the thickness of the A1 pulley and a power Doppler assessment of the pulleys, tendons, and tendon sheaths. Results. Thickening and hypoechogenicity of the A1 pulley were found in all patients with trigger fingers. Measurements of A1 pulley thickness were significantly different (P < .0001) between the groups without trigger fingers (mean, 0.5 mm; range, 0.4–0.6 mm) and with trigger fingers (mean, 1.8 mm; range, 1.1–2.9 mm). Hypervascularization of the A1 pulley on power Doppler imaging was found in 91% of the trigger fingers but was never found in the healthy control group. Flexor tendinosis was found in 48% of the trigger fingers; tenosynovitis was found in 55%; and both were found in 39%. In the control group, tenosynovitis and tendinosis were not found. Conclusions. Thickening and hyper‐vascularization of the A1 pulley are the hallmarks of trigger fingers on sonography. Other frequently observed features include distal flexor tendinosis and tenosynovitis.

Standard and high resolution magnetic resonance imaging of glomus tumors of toes and fingertips

BACKGROUND High-resolution magnetic resonance imaging (MRI) of subungual glomus tumors has been recently reported. OBJECTIVE Our purpose was to compare high-resolution MRI and standard MRI for the diagnosis of 44 glomus tumors of the toes and fingertips. METHODS Glomus tumors (11 cases) were first examined by MRI with a commercial surface coil (set 1). Thirty-three other glomus tumors and one tumor from set 1 were then examined with a high-resolution module designed for skin imaging (set 2). RESULTS All 44 glomus tumors were identified with MRI. The limits of the tumors were detected in 54% of set 1 and 100% of set 2. A capsule was present in most cases, but was incomplete or absent in eight cases. Subtypes of glomus tumors were more easily differentiated in set 2. CONCLUSION Standard MRI was adequate to detect glomus tumors, but high-resolution MRI assessed tumor characteristics more accurately.

Longitudinal stress fractures of the tibia: comparative study of CT and MR imaging.

Abstract. The aim of this study was to compare the performance of CT and MRI in the diagnosis of longitudinal stress fracture of the tibia (LSFT). A retrospective study of imaging findings was performed in 15 patients with LSFT. The CT and MR images were compared for detection of fracture line, callus, bone marrow edema, and soft tissues changes. The CT and MRI techniques allowed the detection of the fracture line in 82 and 73 % of cases, respectively. The callus was always visualized with CT or MRI. The MRI technique had a markedly higher sensitivity than CT in the detection of bone marrow edema (73 vs 18 %) and soft tissue lesions (87 vs 9 %). This may cause a misleading aggressive appearance on MRI. Computed tomography remains the best imaging modality for diagnosis of LSFT. However, MRI findings should be known to obviate the performance of CT or bone biopsy.

Predictive factors of hand radiographic lesions in systemic sclerosis: a prospective study

Objective To examine the outcomes of hand radiographic x-rays in patients with systemic sclerosis (SSc) and to identify risk factors for the progression of hand radiographic lesions in a prospective cohort. Methods Dual time-point x-rays were systematically performed after a median interval of 5 years (range 4–7 years) in 103 consecutively recruited patients with SSc. Univariate and multivariate Cox proportional hazards models evaluated predictors of progression of hand radiographic lesions. Results Radiographic progression of erosive arthritis, acro-osteolysis, calcinosis and flexion contracture occurred in 24, 22, 27 and 18 patients, respectively. Multivariate Cox regression analysis did not identify any predictor of the progression of erosive arthritis. Digital ulcers were shown independently to predict the progression of acro-osteolysis and calcinosis (HR 12.43, 95% CI 1.97 to 88.40 and 3.16, 95% CI 1.22% to 9.43%, respectively). The diffuse cutaneous subset was shown to be an independent predictor of the progression of flexion contracture (HR 7.52, 95% CI 1.21 to 43.93). Conclusion The results highlight the striking level of hand radiographic lesions in SSc and suggest close monitoring of patients with the diffuse cutaneous subset for the occurrence or worsening of this complication. The results also show that severe peripheral vascular involvement predicts both acro-osteolysis and calcinosis, highlighting their vascular background.

Comparative study of MRI and power Doppler ultrasonography of the heel in patients with spondyloarthritis with and without heel pain and in controls

Introduction Imaging of heel enthesopathy in spondyloarthritis (SpA) could potentially be useful for diagnosis and monitoring. The aim of this study was to assess the diagnostic capacities of MRI and power Doppler ultrasonography (PDUS) of the heel to distinguish patients with SpA from controls and to distinguish between patients with SpA with and without enthesopathy. Methods A cross-sectional single-centre study was performed in 51 patients (102 heels) with definite SpA according to Amors criteria. Patients with degenerative non-inflammatory low back pain (n=24, 48 heels) were included as controls. Bilateral heel MRI and PDUS were performed by two senior musculoskeletal radiologists blinded to the clinical and biological data on the same day as the clinical evaluation. The data were analysed by patient and by heel. Results Neither MRI nor PDUS could discriminate between patients with SpA and controls; bone oedema on MRI was the only abnormality specific to SpA (94%), but with a poor sensitivity (22%). However, among patients with SpA, painful heels had more inflammatory abnormalities (81% by MRI, 58% by PDUS) than heels with no pain (56% at MRI, 17% at PDUS). Conclusion Heel MRI and PDUS frequently show inflammatory lesions in SpA, particularly in painful heels. However, they were also often abnormal in controls. These results suggest that heel MRI and PDUS cannot be used for the diagnosis of SpA. However, PDUS and MRI may be useful for the depiction and assessment of enthesis inflammatory lesions in patients with SpA with heel pain.

Cervical spine and crystal-associated diseases: imaging findings

The cervical spine may be specifically involved in crystal-associated arthropathies. In this article, we focus on the three common crystals and diseases: hydroxyapatite crystal deposition disease, calcium pyrophosphate dihydrate (CPPD) deposition disease, and monosodium urate crystals (gout). The cervical involvement in crystal-associated diseases may provoke a misleading clinical presentation with acute neck pain, fever, or neurological symptoms. Imaging allows an accurate diagnosis in typical cases with calcific deposits and destructive lesions of the discs and joints. Most of the cases are related to CPPD or hydroxyapatite crystal deposition; gout is much less common.

MRI Assessment of Recurrent Carpal Tunnel Syndrome After Open Surgical Release of the Median Nerve

OBJECTIVE The purpose of this study was to retrospectively determine the accuracy of MRI in identification of the morphologic features of median nerve dysfunction after surgical release of the median nerve for carpal tunnel syndrome. MATERIALS AND METHODS Two blinded readers independently evaluated axial 1.5-T MR images for retinacular regrowth, morphologic characteristics of the median nerve, and presence of mass effect, fibrosis, and carpal tunnel decompression. All 47 patients (11 men, 36 women; mean age, 55 years; range, 27-81 years) had undergone open surgical release of the median nerve for carpal tunnel syndrome. Thirty-five patients had electromyographic evidence of recurrent carpal tunnel syndrome. The other 12 patients did not have electrophysiologic evidence of recurrent carpal tunnel syndrome and were the control group. RESULTS A statistically significant difference between the recurrent carpal tunnel syndrome and control groups was found for fibrosis (p = 0.009), nerve enhancement (p = 0.04), and median nerve width (p = 0.008) and ratio (p = 0.01) at the pisiform level. CONCLUSION MRI may be used in association with electromyography for accurate postoperative evaluation of the carpal tunnel.