Sofiane Bendaoud, Presenter: Nothing to Disclose

Martine J. Remy-Jardin MD, PhD, Abstract Co-Author: Nothing to Disclose

Benoit Wallaert MD, PhD, Abstract Co-Author: Nothing to Disclose

Nunzia Tacelli MD, Abstract Co-Author: Nothing to Disclose

Andrei Bogdan Gorgos MD, Abstract Co-Author: Nothing to Disclose

Jacques Remy MD, Abstract Co-Author: Nothing to Disclose

To compare diagnostic information and radiation dose between volumetric and sequential scanning in the follow-up of chronic diffuse lung diseases.

43 patients (mean age: 33.5 yr) underwent a noncontrast high-resolution volumetric CT examination of the entire chest on a 64-slice MDCT scanner (Definition, Siemens) as part of the follow-up of cystic fibrosis (n=17) and diffuse infiltrative lung disease (n=26). Each volumetric scan was obtained with an individually-adapted selection of the kilovoltage and milliamperage, completed by 4D tube current modulation. Thin-collimated lung images of volumetric scans were interpreted by consensus between two radiologists to assess the presence and extent of lung parenchyma and airways abnormalities which was considered the reference standard. A second set of thin-collimated lung images, spaced 10 mm apart, was created from each volumetric scan (i.e., the sequential scan), leading to a second reading session, several weeks apart. The DLP value of each volumetric scan was recorded; the DLP value of the corresponding sequential scan was retrospectively calculated.

The mean patients’ weight was 60.9 kg (80 kV: n=9; 100 kV: n=29; 120 kV: n=5). No statistically significant difference was observed between volumetric and sequential scans in (a) the identification of abnormal bronchial wall thickening (p=0.32), bronchiectasis (p=1), areas of ground glass attenuation (p=1), airspace consolidation (p=1), lung infiltrates (p=1), emphysema (p=0.32) and cystic lesions (p=1); (b) the regional distribution of lung changes (focal vs diffuse abnormalities; p=1; upper-middle-lower lobe abnormalities; p=1; uni- or bilateral abnormalities; p=1), leading to similar diagnostic information from each series of images. The mean radiation dose of sequential scans (mean DLP: 14.8 +/- 8.4 mGy.cm) was significantly lower than that of the volumetric scans (DLP: 75.5 +/- 42.8 mGy.cm) (p=0.001).

The magnitude of dose reduction without loss of diagnostic information achievable with sequential scans suggests reconsidering sequential scanning in the follow-up of chronic diffuse lung diseases in young adults.

Continuous scanning can be efficiently replaced by sequential HRCT enabling substantial minimization of the radiation dose without compromising diagnostic information.

Bendaoud, S, Remy-Jardin, M, Wallaert, B, Tacelli, N, Gorgos, A, Remy, J, Follow-up of Chronic Diffuse Lung Diseases in Young Adults: Is Volumetric CT Scanning of the Chest Justified?.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6010775.html