Search

Conventional radiography is the first modality to investigate the radio-ulno-carpal joint in the event of trauma or instability. This study sought to determine the reliability of cone beam computer tomography (CBCT) and scout of view in evaluating carpal alignment compared with conventional radiographs in order to assess the influence of wrist kinematics on usual measurements.We prospectively recruited 305 patients who successively underwent plain radiography and CBCT. 51 patients with prior acute unilateral wrist trauma were eligible for entry into the study (mean age of 39 years). Three blinded readers performed the measurements separately. The axial method and bony axial lines defined previously in the literature were applied, with three categories of measurements performed, consisting of distal radio-ulnar, radiocarpal, and radio/carpometacarpal measurements. Intraclass correlation coefficients (ICCs) for paired t-test were calculated to assess inter- and intra-observer agreements.Inter-observer agreement was very high (0.94) for all modalities. Intra-observer reliability between scout view and CBCT was almost perfect for all measurements. Intra-observer reliability between radiograph and scout view/CBCT was perfect for distal radio-ulnar measurements, substantial for radio-carpal, and moderate for radio/carpometacarpal measurements.In the absence of a strict position control between two imaging acquisitions, only distal radio-ulnar measurements were shown perfectly reliable when using these two imaging methods, which is suggestive of a minor relevance of ulnar/radial deviation. Excepting for some angles, the radio-carpal and radio-carpometacarpal measurements were shown to differ according to wrist position, being thus more sensitive to flexion/extension of the wrist.

Although the nail is a small anatomical structure, it can be affected by various tumors and tumor-like conditions. Because of the distinctive nail anatomy, the clinical presentation of tumors is modified, thus rendering the diagnosis challenging. As nail biopsy and surgery are painful procedures associated with an increased risk of permanent onychodystrophy, pre-operative diagnosis is desirable. Although conventional radiographs are still the first-line radiologic examination for the assessment of bony structures beneath the nail matrix, they do not allow detailed evaluation of the phalangeal soft tissues. High resolution MRI allows accurate detection and mapping of nail lesions and can suggest a specific diagnosis. This review focuses on high resolution MRI of nail tumors and tumor-like lesions. We review the nail anatomy and the optimal MRI protocol. We then discuss a variety of tumors and tumor-like lesions in relation to the clinical presentation, anatomic location, histological features and imaging characteristics. We herewith describe common benign tumors (glomus tumor, onychomatricoma, keratoakanthoma, fibroma, subungual exostosis, hemangioma, chondroma, pyogenic granuloma), malignant tumors (subungual melanoma, subungual squamous cell carcinoma), as well as tumor mimics (mucoid cyst, epidermoid cyst). Although not entirely specific, MRI is a valuable tool in treatment planning of these tumors.

Imaging plays an essential role for the detection and analysis of pathologic conditions of the brachial plexus. Currently, several new techniques are used in addition to conventional 2D MR sequences to study the brachial plexus: the 3D STIR SPACE sequence, 3D heavily T2w MR myelography sequences (balanced SSFP=CISS 3D, True FISP 3D, bFFE and FIESTA), and the diffusion-weighted (DW) neurography sequence with fiber tracking reconstruction (tractography). The 3D STIR sequence offers complete anatomical coverage of the brachial plexus and the ability to slice through the volume helps to analyze fiber course modification and structure alteration. It allows precise assessment of distortion, compression and interruption of postganglionic nerve fibers thanks to the capability of performing maximum intensity projections (MIP) and multiplanar reconstructions (MPRs). The CISS 3D, b-SSFP sequences allow good visualization of nerve roots within the spinal canal and may be used for MR myelography in traumatic plexus injuries. The DW neurography sequence with tractography is still a work in progress, able to demonstrate nerves tracts, their structure alteration or deformation due to pathologic processes surrounding or located along the postganglionic brachial plexus. It may become a precious tool for the understanding of the underlying molecular pathophysiologic mechanisms in diseases affecting the brachial plexus and may play a role for surgical planning procedures in the near future.