Magnetic Resonance Imaging (MRI) Analysis of Tissue Sodium Concentration in Chronic Kidney Disease.

Human body sodium is regulated by the kidneys and extrarenal mechanisms. Stored skin and muscle tissue sodium accumulation is associated with kidney function decline, hypertension, and a pro-inflammatory and cardiovascular disease profile. In this chapter, we describe the use of sodium-hydrogen magnetic resonance imaging (23Na/1H MRI) to dynamically quantify tissue sodium concentration in the lower limb of humans. Real-time quantification of tissue sodium is calibrated against known sodium chloride aqueous concentrations. This method may be useful for investigating in vivo (patho-)physiological conditions associated with tissue sodium deposition and metabolism (including in relation to water regulation) to enlighten our understanding of sodium physiology.

Oblique proximal locking screw in tibial fracture intramedullary nailing: a clinical imaging study of proximity to common peroneal nerve.

Intramedullary nailing (IMN) is the treatment of choice in the surgical management of most tibia shaft fractures. The aim of the study was to evaluate the proximity of the common peroneal nerve (CPN) to the oblique proximal locking screw inserted from the anteromedial to the posterolateral direction. We identified all the patients who underwent the IMN of the tibia between 2008 and 2018. Patients who underwent post-operative computed tomography for any reason were identified. Patients were included if the CPN was visible on the axial slices, the proximal oblique locking screw was used, or the line of the drilling could be reconstructed. Twenty-nine patients met the inclusion criteria. The median length of the intramedullary nail was 345 mm. The median nail diameter was 10 mm. The median number of proximal interlocking screws was 2. All scans were reviewed by the musculoskeletal radiologist for verifying the visibility and marking of the CPN. The mean screw trajectory angle to the CPN was 9° (± 9°). Most of the drilling trajectories passed posterior to the CPN (79%). The depth of the intramedullary nail was on average - 8 mm (± 10 mm). A negative correlation was observed between the depth of the nail and the distance from the CPN (P < 0.001). During the insertion of the oblique proximal locking screw from the anteromedial to the posterolateral direction, the CPN is potentially at risk if the drill is allowed to plunge or an incorrectly long screw is used. Sinking the nail provides a better margin of safety.

Focal lesions on magnetic resonance imaging in aplastic anaemia: multiple metastases or haemopoietic marrow.

We describe the imaging findings in the spine of a 26-year-old man with aplastic anaemia who is undergoing immunosuppressive therapy. Magnetic resonance imaging of the thoracolumbar spine revealed multiple focal low signal intensity lesions involving most of the thoracic and lumbar vertebral bodies. A CT-guided biopsy of one of these lesions was performed at the level of L2, demonstrating normal haemopoietic tissue, with no evidence of lymphoma or metastases. Magnetic resonance imaging of bone marrow has been widely described previously, but few reports have examined the pattern of marrow regeneration following immunosuppressive therapy. The presence of low signal intensity lesions scattered through high signal intensity fatty marrow usually raises suspicion of pathology such as lymphoma, metastases or myeloma. In this case, the low signal intensity lesions represent regenerating, expanding haemopoietic marrow.

The outcome of clinical parameters in adults with severe Type I Gaucher disease using very low dose enzyme replacement therapy.

Enzyme replacement therapy is now well established as the treatment of choice in Type I Gaucher disease. Historically higher dosage regimens have been used in preference to lower doses despite the little clinical evidence in the way of large controlled clinical trials to support this. Moreover, the extraordinary cost of therapy means that not all eligible patients are able to be treated at the higher dose. Twelve type I adult patients with relatively severe disease were commenced on a very low dose of 7.5U of alglucerase/imiglucerase per kg every two weeks (initially given thrice weekly and later weekly). Follow-up 5 year data reveal a good visceral and haematological response with outcomes consistent with recently published treatment guidelines. Satisfactory clinical and radiological skeletal improvement was also demonstrated in most patients. Three patients had an inadequate overall skeletal response to therapy. Biomarkers also steadily improved although perhaps not quite at the same rate as that seen in higher doses. Very low dose enzyme replacement therapy may be appropriate for adult type I Gaucher patients with mild-moderate skeletal disease.