No abstract

Of 293 patients who underwent computed tomography (CT), surgery, and pathologic examination for chronic sinusitis, 25 had a diagnosis of fungal sinusitis at pathologic examination. Of these, 22 had foci of increased attenuation at CT (in four patients the mean representative CT number [Hounsfied unit] was 122.2 HU [SD, 8.2 HU]), and three did not. Of the 22, 19 patients (76%) met the CT criterion of this study (there was a 12% false-positive and a 12% false-negative diagnostic rate). Six of the 19 patients and one additional patient underwent magnetic resonance (MR) imaging, and all demonstrated remarkably hypointense signal characteristics on T2-weighted images. The findings at MR imaging therefore appear more characteristic of fungal sinusitis than the findings at CT. Furnace atomic absorption spectrometry showed increased concentrations of iron and manganese in mycetoma compared with their concentrations in bacterially infected mucus. This finding and the presence of calcium in the fungal concretion may explain the hypointense T2-weighted signal on MR images.

Recent advances in the understanding of mucociliary activity and the pathophysiology of the nasal cavity and paranasal sinuses have revolutionized the surgical management of chronic and/or recurrent sinusitis. Meticulous radiographic delineation of the small structures in this region, coupled with endoscopic evaluation, provides detailed preoperative information regarding morphology and pathology. This information has led to more focused endoscopic surgical procedures, which have dramatically reduced patient morbidity. As a consequence, there is now worldwide interest among otolaryngologists in the radiologic definition of paranasal regional anatomy. For effective interactions between radiologist and otolaryngologist, the former must be prepared to render interpretations that address these "microanatomic" locales. This communication is directed at familiarizing the radiologist with these observations and concepts, considering both normal and disturbed anatomy with their attendant pathophysiologic and therapeutic implications.

No abstract

Computed tomography (CT) has become the first modality to provide the patient's self-brain map for stereotactic neurosurgery. This paper describes our development of a nearly artifact-free stereotactic frame designed for CT imaging. The surgical procedure is performed within the CT scanner itself. The scanner's computer, via a new software program, spatially integrates the new stereotactic frame with the CT images of the patient and with the scanner gantry to provide rapid coordinate determinations, calculate potential probe trajectories, obtain target accuracy within 1 mm, and observe for any procedural complications. Our initial clinical experience with this system is described.