Digital tomosynthesis and ground glass nodules: Optimization of acquisition protocol. A phantom study.

INTRODUCTION: Ground-glass nodules may be the expression of benign conditions, pre-invasive lesions or malignancies. The aim of our study was to evaluate the capability of chest digital tomosynthesis (DTS) in detecting pulmonary ground-glass opacities (GGOs). METHODS: An anthropomorphic chest phantom and synthetic nodules were used to simulate pulmonary ground-glass nodules. The nodules were positioned in 3 different regions (apex, hilum and basal); then the phantom was scanned by multi-detector CT (MDCT) and DTS. For each set (nodule-free phantom, nodule in apical zone, nodule in hilar zone, nodule in basal zone) seven different scans (n = 28) were performed varying the following technical parameters: Cu-filter (0.1-0.3 mm), dose rateo (10-25) and X-ray tube voltage (105-125 kVp). Two radiologists in consensus evaluated the DTS images and provided in agreement a visual score: 1 for unidentifiable nodules, 2 for poorly identifiable nodules, 3 for nodules identifiable with fair certainty, 4 for nodules identifiable with absolute certainty. RESULTS: Increasing the dose rateo from 10 to 15, GGOs located in the apex and in the basal zone were better identified (from a score = 2 to a score = 3). GGOs located in the hilar zone were not visible even with a higher dose rate. Intermediate density GGOs had a good visibility score (score = 3) and it did not improve by varying technical parameters. A progressive increase of voltage (from 105 kVp to 125 kVp) did not provide a better nodule visibility. CONCLUSION: DTS with optimized technical parameters can identify GGOs, in particular those with a diameter greater than 10 mm. IMPLICATIONS FOR PRACTICE: DTS could have a role in the follow-up of patients with known GGOs identified in lung apex or base region.

Radiological-pathological correlation in intratumoural tissue components of solid lung tumours.

The aim of this paper is to describe the intratumoural tissue components of solid lung tumours evidenced by macroscopic and/or microscopic examination of the autopsy or surgical specimen and visible on computed tomography (CT) without and with contrast material administration. Seven intratumoural tissue components can be identified both at CT and at pathology: (1) solid component, (2) haemorrhagic component, (3) coagulation necrosis, (4) liquefaction necrosis, (5) parenchymal consolidation, (6) diffuse peripheral component and (7) fibrotic component. Necrotic and haemorrhagic components are typically observed in malignant lesions, whereas solid and fibrotic components may be seen both in solid lung malignancies and in benign lesions.