John Mikey Troupis MBBS, FRANZC, Presenter: Nothing to Disclose

Sundeep Singh Pasricha MBBS, Abstract Co-Author: Nothing to Disclose

Stephen Leonard Stuckey MBBS, Abstract Co-Author: Nothing to Disclose

Julian Smith, Abstract Co-Author: Nothing to Disclose

Cliff Choong MBBS, Abstract Co-Author: Nothing to Disclose

Dynamic 4D 320 MDCT is useful in the evaluation of possible surgical respectability of initially suspected inoperable lung cancer.

When a lung cancer is contiguous with adjacent structures on routine spiral CT and lacks a cleavage plane, determination of operability may be difficult. We investigate a novel technique utilising 16cm z axis coverage of 320MDCT which provides high resolution scanning in the non spiral mode. If continuous scanning is used without table feed, high resolution 4D imaging which can be assessed as a motion volume data set in any plane. We investigated the possibility of detection of differential motion between two adjacent non tethered structures suggesting resectability.

8 patients with lung cancers adjacent to vital structures or chest wall were examined. Three cases were abutting the chest wall, three adjacent to major vessels, and two in the lung apex. Differential motion between the tumour and adjacent structure on 4-D CT was considered indicative of the absence of frank invasion. 4D CT imaging revealed differential motion between cancer and the adjacent structure in all cases, on real time (motion) workstation analysis. Intraoperative assessment confirmed resectability of the cancers in all 8patients.

Tube rotation, 350 msec, 180 degree interpolation, with 175 milliseconds temporal resolution. Approximately six ‘phases’(images) per second were obtained. The 16cm z-axis volume was centred over the mass. The patient's breathing rate was adjusted until one full respiratory cycle occurred every 3.5 seconds.Each scan volume was reconstructed using contiguous 0.5mm slices. Intravenous iodine contrast administration varied depending on the exact site of the mass. If in the right lung apex, enhancement of the SVC was deemed optimal and IV contrast was administered with appropriate dilution and volume. The aorta and SVC were therefore simultaneously enhanced. If the mass was located directly adjacent to a calcified aorta, no contrast was utilised. The calcified plaques in the aortic wall were used as a landmark to determine if the mass moved independently. If adjacent to ribs, contrast was not required.

Troupis, J, Pasricha, S, Stuckey, S, Smith, J, Choong, C, Four-Dimensional 320 MDCT for Determination of Operability of Lung Cancer.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12026597.html