Aims and objectives
Multidector helical computed tomography (MDCT) is considered the reference exam for imaging of inflammatory disease in the paranasal sinuses thanks to its high spatial resolution. It is performed to rule out sinusitis (both acute and chronic),
to differentiate mucosal disease patterns and to plan surgery. Because paranasal imaging is often performed in young patients without life-limiting disease and repetitive exams may be required,
radiation dose is of special concern. According to ALARA...
Methods and materials
Twenty patients (median age 47,
range 32-60 years) were randomly selected for an ultra-low-dose protocol,
instead of a low-dose protocol. All patients signed a written informed consent before image acquisition. Scans were performed with a CT General Electric Revolution EVO,
64 slices. Technical parameters used in the standard low-dose protocol were: 100 kV,
64x0.625 mm slice collimation; while the ultra-low-dose protocol was set as follows: 80 kV,
64x0.312 mm slice collimation....
All scans were considered to be of adequate diagnostic quality (median score was 4.6). Regarding radiation exposure,
in both protocols we evaluated Size and Size-Specific Dose Estimates in CT (SSDE),
Computer Tomography Dose Index (CTDI vol) and Dose Lenght protocol (DLP). Results are shown in Fig 1. Radiation exposure was significant smaller in the ultra-low-dose protocol group,
decreasing radiation dose approximately to 50% with respect to the standard low-dose protocol.
In a small group of patients,
we demonstrated radiation exposure from low-dose CT can be further reduced by 50% in maxillofacial CT,
without losing diagnostic image quality. This achievement is of paramount importance,
in particular when dealing with young patients.
1. Wuest W,
Lell M (2016).
Low-Dose CT of the Paranasal Sinuses: minimizing X ray Exposure with Spectral Shaping.
Eur Radiol 26:4155-4161. 2. Duvoisin B,
Schnyder P (1991) Low-dose CT and inflammatory disease of the paranasal sinuses.
Neuroradiology 33:4036 3. Tack D,
De Maertelaer V,
Gevenois PA (2003) Comparison between low-dose and standard-dose multidetector CT in patients with suspected...