Role Of Multidetector Computed Tomography In The Evaluation Of Diseases Of Paranasal Sinuses

Abstract

Diseases of the Paranasal sinuses include wide spectrum ranging from inflammatory conditions to neoplasms, both benign and malignant. The conventionalplain radiographyreadilydemon- strates maxillary and frontal sinus disease they provide limited views of the anterior ethmoid cells, the upper thirds of the nasal cavity and the frontal recess. Imaging of the PNS has progressed from conventional radiographs (plain films) almost exclusively into the realms of computed tomography (CT) and magnetic resonance imaging (MRI). Technological advances in these two imaging modalities have provided more precise differential diagnosis and greater detail about the anatomic extent of the diseases of PNS. These provide sufficient information for diagnosis and surgical planning for the otolaryngologist. CT has replaced conventional radiographs as imaging modality of choice for assessment of PNS diseases. CT resulted in the widespread development of endoscopic sinus surgery (ESS) for inflammatory sinonasal diseases. CT Plays an important role in the evaluation of pre-operative patients considered for FESS called SSCT (Screening sinus CT). It is now mandatory and a medico legal requirement to evaluate PNS and nose before FESS, guides the otolaryngologist during surgery and serves to direct the surgical approach. CT determines the distribution and extent of disease and detect those anatomic variations (like septal deviation, spur formation, concha bullosa, paradoxical curve of middle turbinate etc.) which places patients at increased risk for intra operative and post operative FESS complications and also reducing the morbidity and mortality of patients. 2 CT excels over MRI at evaluating fine bone details, assessment of fibro- osseous lesions of PNS and sino facial trauma. Orbital and brain anatomy is visualized better at MR imaging than at CT. With the unique ability of CT to image both the bones and soft tissues, direct coronal scanning and sagittal reconstruction, imaging the space occupying lesions has been revolutionalised. Accurate extent of disease and micro anatomic locales provide a reliable preoperative guide for endoscopic sinus surgery. A combination of CT and diagnostic endoscopy has become the corner stone in evaluation of the paranasal sinus diseases. Hence CT has immense value and offers standard imaging of paranasal sinus diseases.