Hrct

high resolution computed tomography, a CT technique using thin collimation and image reconstruction with a high resolution algorithm in order to obtain detailed images of lung morphology. HRCT is used to image diffuse lung disease and focal lung lesions, and to obtain accurate measurements of the attenuation of a solitary pulmonary nodule or masses.

In patients with diffuse lung disease, HRCT is obtained at selected or spaced levels (e.g. at 1-2 cm intervals) in order to sample lung anatomy. In comparison to plain radiographs, HRCT has greater sensitivity and specificity, and allows a more accurate diagnosis to be made. It is often obtained in patients with suspected chronic diffuse infiltrative lung disease, as it is able to show lung abnormalities when chest films are normal, clearly characterize morphological abnormalities which are present and help determine if lung disease is active or inactive, and is of value in localizing specific sites for biopsy. Scanning is usually obtained in the supine position at full inspiration, but prone and expiratory images are sometimes obtained.

In patients with a focal lesion or solitary nodule, high resolution images are often obtained through the lesion in order to assess morphology and detect calcium or fat.

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