Computed tomography and/or magnetic resonance imaging for pre-operative planning for inverted nasal papilloma: review of evidence

Background:Inverted nasal papilloma is a benign tumour with variable biological behaviour. It is a unique neoplasm and is often difficult to manage, being characterised by a tendency to recur following excision, an association with malignancy and an ability to destroy bone. Radiological diagnosis has traditionally been based on computed tomography, but it is often impossible to differentiate between polyps with entrapped debris and inverted nasal papilloma. Magnetic resonance imaging, especially T2-weighted images, is perhaps a better tool in differentiating inverted nasal papilloma from other nasal lesions, and has recently been advocated as the imaging modality of choice.Aims:To review the evidence on the ideal imaging modality for pre-operative planning of surgery for patients with histologically proven inverted nasal papilloma.Materials and methods:A systematic review of studies was undertaken, focusing on radiological assessment of inverted nasal papilloma (primary and recurrent). All English language articles were potentially included in the review. However, we excluded single case reports, case series, pictorial essays, ‘teaching’ reviews and reviews of inverted nasal papilloma not focusing on pre-operative imaging.Results:Sixteen studies were identified based on our search strategy. Only 10 fulfilled our criteria. Computed tomography scanning was the standard imaging modality of choice for assessing sinus involvement of inverted papilloma and for planning the extent of surgery. T2-weighted magnetic resonance imaging scans were able to distinguish tumour (intermediate signal) from inflammatory tissues (bright signal), but not post-operative scarring from recurrent tumour. No studies were found which compared the specificity and sensitivity of magnetic resonance imaging and computed tomography in the accurate pre-operative identification of the extent of inverted papilloma.Conclusions:There is currently not enough evidence to suggest one sole modality as providing optimum imaging for inverted nasal papilloma. Computed tomography remains the imaging modality of first choice for inverted nasal papilloma, despite certain disadvantages. Magnetic resonance imaging is able to distinguish tumour from inflammation and is advocated as a better tool for recurrent tumour, but bone destruction of sinus walls is less easy to recognise, compared with computed tomography. Evaluation of sinus tumours usually involves both imaging modalities, and inverted nasal papilloma should be included within this pathological group. The cohort of patients is usually small, so cost-effectiveness should not generally be an issue when considering whether to use computed tomography, magnetic resonance imaging or both. A well structured, prospective study is needed to evaluate the efficacy of magnetic resonance imaging versus computed tomography for pre-operative planning of histologically proven inverted nasal papilloma.