Paranasal sinuses: low-dose CT.

Abstract

While computed tomography (CT) has become an important imaging modality in the evaluation of the paranasal sinuses, the radiation dose remains higher than is necessary. With use of a head phantom and constant kilovolt peak setting, axial and coronal CT scans of the paranasal sinuses were obtained at each of six successively lower milliampere second settings than are commonly used in clinical practice. Although noise, as measured by the standard deviation of the CT numbers, did increase, images were of diagnostic quality even when dose levels were reduced by a factor of 28. In the same incremental manner, the milliampere second settings used in scanning 90 patients were reduced, with no loss of diagnostic quality. The authors discuss the methods of analysis and the advantages of use of lower milliampere second settings at CT scanning of the sinuses.

Comparison of Image Quality and Radiation Dose between Fixed Tube Current and Combined Automatic Tube Current Modulation in Craniocervical CT Angiography

“…However, a reduction of radiation dose will increase image noise, which may compromise image quality to a variable extent. 2,12,17,19,21,22 Previous studies on CT of the head and neck, chest, abdomen, and pediatric pelvis have suggested the possibility of reducing tube currents without jeopardizing imaging quality, 17,19,[23][24][25][26][27][28] but the tube current in those studies was adjusted manually. Such manual adjustment of tube current, based on patient weight or dimensions, can aid in establishing an appropriate balance between image noise and radiation exposure.…”

Radiation Dose Reduction in Paranasal Sinus CT Using Model-Based Iterative Reconstruction

“…1,2 Greater attention has been directed toward adjusting CT parameters, most commonly through the reduction of milliampere-second (mAs) (tube current time product), to allow reduced radiation exposure while maintaining acceptable image quality. [3][4][5][6][7][8][9][10][11][12][13] Recently, high-pitch dual source multidetector CT systems have shown promise of even greater dose reduction. 14,15 Nevertheless, because of progressively decreasing signal-to-noise, a threshold for tube output is invariably reached, below which imaging becomes unacceptable.…”

CT Radiation Dose for Computer-Assisted Endoscopic Sinus Surgery: Dose Survey and Determination of Dose-Reduction Limits

“…First, we used a dedicated low-dose protocol for sinusitis (sinusitis CT, 30 mAs) as amply described in the literature. [9][10][11] Second, we used a high-dose protocol for optimal soft-tissue delineation (140 mAs). Third, we had a dedicated protocol for CAS-CT (210 mAs).…”