MRI scanning without magnet removal is safe and well tolerated in NF2 patients with auditory implants. With appropriate MRI sequences, the image quality is not significantly impaired.
A survey of the 2075 cases in the Leeds Bone Tumour Registry showed that 54 cases of Primary Lymphoma of Bone that had been registered since data collection began in 1958 (2.6% of primary bone tumours). The overall sex ratio was 1.5 males: 1 female, largely due to the preponderance of males in the under 40 age group. The age distribution was bimodal, the second peak of incidence demonstrating a significant reversal of the sex ratio with females being more commonly affected in the older group. The clinical features and radiological findings were non-specific, diagnosis relying principally on tissue histology. The overall survival at five years was 46% and was not affected by the interval from the onset of symptoms until the final diagnosis.
ObjectiveAccurate and precise measurement of vestibular schwannoma (VS) size is key to clinical management decisions. Linear measurements are used in routine clinical practice but are prone to measurement error. This study aims to compare a semi-automated volume segmentation tool against standard linear method for measuring small VS. This study also examines whether oblique tumour orientation can contribute to linear measurement error.Study designExperimental comparison of observer agreement using two measurement techniques.SettingTertiary skull base unit.ParticipantsTwenty-four patients with unilateral sporadic small (< 15 mm maximum intracranial dimension) VS imaged with 1 mm-thickness T1-weighted Gadolinium enhanced MRI.Main outcome measures(1) Intra and inter-observer intraclass correlation coefficients (ICC), repeatability coefficients (RC), and relative smallest detectable difference (%SDD). (2) Mean change in maximum linear dimension following reformatting to correct for oblique orientation of VS.ResultsIntra-observer ICC was higher for semi-automated volumetric when compared with linear measurements, 0.998 (95% CI 0.994–0.999) vs 0.936 (95% CI 0.856–0.972), p < 0.0001. Inter-observer ICC was also higher for volumetric vs linear measurements, 0.989 (95% CI 0.975–0.995) vs 0.946 (95% CI 0.880–0.976), p = 0.0045. The intra-observer %SDD was similar for volumetric and linear measurements, 9.9% vs 11.8%. However, the inter-observer %SDD was greater for volumetric than linear measurements, 20.1% vs 10.6%. Following oblique reformatting to correct tumour angulation, the mean increase in size was 1.14 mm (p = 0.04).ConclusionSemi-automated volumetric measurements are more repeatable than linear measurements when measuring small VS and should be considered for use in clinical practice. Oblique orientation of VS may contribute to linear measurement error.
Although the survival figures in this series are comparable with the best outcomes from other units, our experience would suggest improvements can still be achieved by reconsidering the selection of patients for neck dissection and temperomandibular joint excision in early stage disease. We also conclude that postoperative radiotherapy should be delivered to all patients, including surgical salvage cases who may have received previous irradiation. Finally, the minority of patients with poor prognostic features should be offered a more palliative therapeutic approach.
By following a policy of treating VS in NF2 patients where tumor growth is observed, complete tumor resection can be achieved through a translabyrinthine approach while achieving comparable facial nerve outcomes to published series. We advocate proactive hearing rehabilitation in all patients with timely assessment for auditory implantation to maintain quality of life.
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