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Imaging, and particularly MRI, plays a crucial role in the assessment of inflammation in rheumatic disease, and forms a core component of the diagnostic pathway in axial spondyloarthritis. However, conventional imaging techniques are limited by image contrast being non-specific to inflammation and a reliance on subjective, qualitative reader interpretation. Quantitative MRI methods offer scope to address these limitations and improve our ability to accurately and precisely detect and characterise inflammation, potentially facilitating a more personalised approach to management. Here, we review quantitative MRI methods and emerging quantitative imaging biomarkers for imaging inflammation in axial spondyloarthritis. We discuss the potential benefits as well as the practical considerations that must be addressed in the movement toward clinical translation of quantitative imaging biomarkers.

Objective: To investigate the use of a quantitative diffusion-weighted imaging (DWI) tool for measuring inflammation of the sacroiliac joints (SIJs) in enthesitis-related arthritis (ERA). Methods: A retrospective study was performed with institutional review board approval. Subjects were adolescents who had undergone MRI of the SIJs since January 2010. 10 patients with a clinical diagnosis of ERA and 10 controls with a clinical diagnosis of mechanical back pain were assessed. Axial T1 weighted, short tau inversion recovery (STIR) and DWI (b-values 0, 50, 100, 300 and 600 mm2 s−1) images were acquired. Apparent diffusion coefficient (ADC) maps were generated using a monoexponential fit. On each of four slices, two to three linear regions-of-interest were placed on each joint. Normalized ADC (nADC) values were defined as joint ADC divided by a reference ADC derived from normal sacral bone. STIR images were scored using a modification of an established technique. The correlation between nADC values and STIR scores was evaluated using Spearman's rank correlation. Results: Mean nADC values were significantly higher in cases than in controls (p = 0.0015). There was a strong correlation between STIR scores and nADC values (R = 0.85). Conclusion: ADC values are significantly increased in inflamed SIJs compared with controls. There is a good correlation between this diffusion-based method and STIR scores of inflammation. Advances in knowledge: We have described and provisionally validated a method for quantifying the severity of inflammation in the SIJs in ERA using ADC measurements. This method is quick, is reproducible and could potentially be automated.

Back pain is common in adult patients with homozygous thalassaemia, and degenerative disc disease is increasingly recognised as a cause. Ultrashort echo time (UTE) pulse sequences, which are sensitive to the presence of short T(2) relaxation components in tissue produced by iron deposition and other processes, were used to examine the lower thoracic and lumbar spine in symptomatic patients with beta-thalassaemia major or intermedia. Three patients were studied with fat suppressed as well as both fat suppressed and long T(2) suppressed UTE (TE=0.08 ms) pulse sequences. Conventional 2D Fourier transformation T(1) and T(2) weighted scans were also performed for comparison. Normal controls showed narrow high signal areas in the region of the end-plate and annulus fibrosus. Patients showed hyperintense bands adjacent to the vertebral end plate in lower thoracic and lumbar spine discs using a UTE sequence with both long T(2) component and fat suppression. The extent of the changes was most marked in the patient with the most severe degenerative change. In the patient with minimal disease, findings of this type were present in discs which did not show evidence of degeneration with conventional MR imaging. High signal changes of a type previously not described were observed in each patient. The effect may be due to organic iron entering the disc and decreasing its T(1) and T(2), but susceptibility effects from iron in the vertebral bodies, fibrosis and other causes also need to be considered.

Adipose cells have traditionally been viewed as a simple, passive energy storage depot for triglycerides. However, in recent years it has become clear that adipose cells are highly physiologically active and have a multitude of endocrine, metabolic, haematological and immune functions. Changes in the number or size of adipose cells may be directly implicated in disease (e.g. in the metabolic syndrome), but may also be linked to other pathological processes such as inflammation, malignant infiltration or infarction. MRI is ideally suited to the quantification of fat, since most of the acquired signal comes from water and fat protons. Fat fraction (FF, the proportion of the acquired signal derived from fat protons) has, therefore, emerged as an objective, image-based biomarker of disease. Methods for FF quantification are becoming increasingly available in both research and clinical settings, but these methods vary depending on the scanner, manufacturer, imaging sequence and reconstruction software being used. Careful selection of the imaging method—and correct interpretation—can improve the accuracy of FF measurements, minimize potential confounding factors and maximize clinical utility. Here, we review methods for fat quantification and their strengths and weaknesses, before considering how they can be tailored to specific applications, particularly in the gastrointestinal and musculoskeletal systems. FF quantification is becoming established as a clinical and research tool, and understanding the underlying principles will be helpful to both imaging scientists and clinicians.

Patient movement is the most common cause of image degradation when performing magnetic resonance scans in children. This is a particular problem scanning at high field, as noise levels of up to 90 dB may be reached. Movement can be reduced by adequate sedation. We present the results of two sedation protocols when scanning with a 1.5T Magnetom scanner. Optimal scan quality can be achieved in up to 85% of scans using Pethco combined with triclofos in children aged 1 month–2 years, and trimeprazine combined with papaveretum in children over 2 years. When heavy sedation is used, patient selection must be cautious, and there is a minimum acceptable level of monitoring including close physical observation, electrocardiographic and apnoea monitoring.

The aim of this study was to develop a method for simultaneous 3D visualization of a new type of artificial urethral sphincter (AUS) and adjacent urinary structures. Serial MR tomograms were acquired from seven men after AUS implantation. 3D reconstruction was performed by thresholding original (positive) and inverted (negative) image intensity and by subsequently fusing positive and negative images. Results show that the bladder, cuff and balloons of the AUS of originally high intensity were imaged in 3D by thresholding the positive datasets. The urethrae and corpora cavernosa penis of originally low intensity were displayed in 3D by thresholding the negative datasets. Fusion of the positive and negative datasets allowed simultaneous visualization of the AUS complex and adjacent urinary structures. All the structures of interest were also clearly seen by interactive multiplanar reformatting. Coronal tomographic datasets provided better 3D and reformatted 2D images than sagittal and transverse datasets. This technique offers a simple means for evaluating the complex urethral anatomy and the AUS, and has potential for improved 3D visualization of many other complex morphological and pathological conditions.

Extension of intravascular tumour thrombus into the right atrium is a well recognized but rare complication of Wilms' tumour (Ritchey et al, 1988). We described the first such case demonstrated by Magnetic Resonance (MR) imaging. A 5-year-old girl was admitted to hospital with a 1-month history of lethargy and one episode of haematuria. Physical examination revealed a large mass in the right loin and elevation of the jugular venous pressure. Abdominal ultrasound demonstrated a 10 cm echogenic, right renal mass. The inferior vena cava (IVC) was expanded by intraluminal thrombus which extended up to the right atrium. Computerized tomography (CT) confirmed a right renal mass and caval thrombus.

A prospective, randomised study on 60 legs in 45 patients examined by ascending lower-limb phlebography was conducted to compare Hexabrix 320 (May and Baker Ltd), iohexol 300 and iohexol 240. The quality of opacification of the veins, side-effects, cost and amount of contrast agent used were compared. All three agents produced adequate examinations. Iohexol 300 was preferred for its denser opacification. Iohexol 240 was associated with the lowest incidence of side-effects and Hexabrix 320 cost the least per examination.

We report the case of a male homosexual known to have the human immunodeficiency virus (HIV) and who presented with an acutely painful mass in the right iliac fossa. The initial clinical diagnosis was of an appendix abscess but subsequent investigation and ultimately laparotomy proved this to be a tuberculous ileal mass. A 30-year-old white English homosexual presented with a 2-week history of pain in the right iliac fossa, fever and general malaise. On examination he was found to have a tender mass in the right iliac fossa and a provisional diagnosis of an appendix abscess was made. In the past he had had several sexually transmitted infections including hepatitis B, syphilis, gonorrhoea, and genital herpes. He had not travelled outside Europe but had recently been found positive for the HIV using the standard Wellcozyme test.