Comparison of lumbar degenerative disc disease using conventional fast spin echo T2W MRI and T2 fast spin echo dixon sequences.

OBJECTIVES: To compare the grading of lumbar degenerative disc disease (DDD), Modic end-plate changes (MEPC) and identification of high intensity zones (HIZ) on a combination of sagittal T1weighted turbo spin echo (T1W TSE), T2weighted fast spin echo (T2W FSE) and short tau inversion recovery (STIR) sequences (routine protocol) with a single sagittal T2W FSE Dixon MRI sequence which provides in-phase, opposed-phase, water only and fat only images in a single acquisition (Dixon protocol). METHODS: 50 patients underwent lumbar spine MRI using the routine protocol with the addition of a T2W FSE Dixon sequence. DDD grade, MEPC and HIZ for each disc level were assessed on the routine and Dixon protocols. Each protocol was reviewed independently by three readers (consultant musculoskeletal radiologists with 26-, 8- and 4 years' experience), allowing assessment of inter-reader agreement and inter protocol agreement for each assessed variable. RESULTS: The study included 17 males and 33 females (mean age 51 years; range 8-82 years). Inter-reader agreement for DDD grade on the routine protocol was 0.57 and for the Dixon protocol was 0.63 (p = 0.08). Inter-reader agreement for MEPC on the routine protocol was 0.45 and for the Dixon protocol was 0.53 (p = 0.02), and inter-reader agreement for identification of the HIZ on the routine protocol was 0.52 and for the Dixon protocol was 0.46 (p = 0.27). Intersequence agreement for DDD grade ranged from 0.61 to 0.97, for MEPC 0.46-0.62 and for HIZ 0.39-0.5. CONCLUSION: A single sagittal T2W FSE Dixon MRI sequence could potentially replace the routine three sagittal sequence protocol for assessment of lumbar DDD, MEPC and HIZ resulting in ~60% time saving. ADVANCES IN KNOWLEDGE: Grading of lumbar DDD, presence of Modic changes and high intensity zones were compared on sagittal T1W TSE, T2W FSE and STIR sequences with a T2W FSE Dixon sequence, with fair-to-good correlation suggesting that three conventional sequences could be replaced by a single Dixon sequence.

An assessment of fluid-fluid levels on magnetic resonance imaging of spinal tumours.

OBJECTIVE: To assess the degree of fluid-fluid levels on MRI in spinal tumours compared with final diagnosis, and the outcome of needle biopsy in such cases. MATERIALS AND METHODS: Retrospective review of patients with a spinal tumour that contained fluid-fluid levels. Data collected included age, sex, spinal location, and final diagnosis. The outcome of needle biopsy was investigated. RESULTS: Forty-two patients were included (19 males; 24 females; mean age 27.5 years, range 5-80 years), the commonest diagnoses being aneurysmal bone cyst (n = 25; 59.5%) and metastasis (n = 5; 11.9%). All patients with a malignant diagnosis were > 50 years of age apart from 2 who had metastases from a known primary cancer, while all patients apart from 1 with aneurysmal bone cyst were < 35 years of age. Needle biopsy was undertaken in 29 cases (69%) and diagnostic in 18 (62%). Patients with FFL occupying > 2/3 of the lesion were significantly more likely to have an aneurysmal bone cyst (p = 0.008) while those with FFL occupying < 2/3 of the lesion were more likely to have a malignant tumour (p = 0.001). The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of > 2/3 FFLs occupying the lesion were 97.1%, 75%, 94.3%, 85.7%, and 92.9% respectively for differentiating a benign from a malignant spinal tumour. CONCLUSIONS: Children and younger adults with spinal lesions containing > 2/3 FFLs were very unlikely to have malignancy. However, in patients > 50 years of age or those with lesions containing < 2/3 FFLs, a malignant lesion is much more likely.

Skeletal staging in Langerhans cell histiocytosis: a multimodality imaging review.

Evaluating the extent of skeletal disease in Langerhans cell histiocytosis (LCH) is a major predictor of patient outcome. Traditionally, whole-body skeletal staging consists of plain radiography and bone scintigraphy. However, more recently whole-body MRI has been shown to be accurate in detecting osseous and extra-osseous lesions, but no large-scale studies analysing its role within the diagnostic algorithm of LCH skeletal staging currently exist. In addition, FDG PET-CT provides useful information regarding disease activity and treatment response, but has an inherent radiation dose which is not ideal in children. Currently, radiographic skeletal survey remains the gold standard with cross-sectional imaging only performed for further characterisation. However, radiographs have shown a wide sensitivity range for skeletal staging and have clear limitations in detecting extra-skeletal disease, a crucial component of stratification in identifying 'at risk' organs. We aim to highlight the various appearances of bony LCH across all the imaging modalities for primary skeletal staging. We will also review the advantages, disadvantages, sensitivity and specificity of each, and establish their role in staging skeletal LCH. Recent studies using whole-body MRI have shown promising results, with radiographs and other modalities playing a more complementary role.

Intrapartum spontaneous pneumomediastinum and surgical emphysema (Hamman's syndrome) in a 30-year-old woman with asthma.

The authors report a case of a 30-year-old nulliparous woman with a prior medical history of asthma who developed intrapartum pneumomediastinum with surgical emphysema during the second stage of labour. She was managed conservatively with supportive care and there was complete resolution of symptoms within 4 days. Clinical and radiological findings were consistent with Hamman's syndrome (spontaneous pneumomediastinum). This case reiterates the possibility of childhood asthma or a family history of asthma as being an associated risk factor for Hamman's syndrome and reminds us of the need to distinguish such clinical findings from more important and potentially life-threatening conditions such as oesophageal rupture, pulmonary embolism and aortic dissection that can present with similar findings.