Mx8000

Details about the imaging procedure have previously been published and are briefly described below [20 (link), 22 (link)]. Examination of the screening group used a multi-slice CT system (16 rows Philips Mx 8000, Philips Medical Systems) performed supine at full inspiration with a low-dose technique (120 kV and 40mAs). Thin slices were reconstructed with a hard algorithm before visual assessment. Two different sets of all scans in random order were created before evaluation by two independent observers (LHT and MMWW) who were blinded to person identification and date of scan. Interstitial lung abnormalities were registered as either absent or present. If present, ILA were categorized as centrilobular, pleural, or paraseptal nodules, ground-glass attenuation, reticulation or honeycombing (Supplementary Table 3) [22 (link)]. The interobserver agreement in the detection of ILA was fair to nearly substantial (kappa 0.60) and has previously been published in more detail [22 (link)]. Statistical analyses were performed on a combined ILA variable, classifying participants as having ILA if at least one observer noted a finding of ILA.

Contrast-enhanced CT examinations were performed using 16- (n = 4), 64- (n = 17), or 256- (n = 5) detector-row scanners (Mx 8000, Brilliance 64, or iCT256; Philips Medical Systems, Cleveland, OH). Each patient was asked to drink 1000 mL of tap water for gastric distension 10 min before the CT examination. Intravenous nonionic contrast material (2 mL/kg; iomeprol, Iomeron 350; Bracco, Milano, Italy) was administered via the antecubital vein, using a power injector (Stellant D, Medrad, Indianola, PA) at a rate of 3 mL/s. Bolus-tracking software (Brilliance; Philips Medical Systems) was used to trigger the scanning 60 s after the aortic enhancement reached a threshold of 150-HU. Helical scan data were acquired using 16×1.5, 64×0.625, or 128×0.625 mm collimation; a rotation speed of 0.5 s; a pitch of 1.25, 0.641, or 0.993; and a kvP of 120 kVp). Using an automatic tube current modulation technique (Dose-Right; Philips Medical Systems), effective mAs ranged from 69 to 379 mAs. Transverse and coronal section datasets were reconstructed with 4-mm thick sections at 3-mm increments.

Imaging of patients in the training data set was performed on one of three Philips scanners: MX8000, Brilliance iCT 256, or Brilliance 40 (Philips Medical Systems, Best, Netherlands). Patients were imaged in the supine position at full inspiration. Scanning parameters were as follows: detector collimation: 0.625–0.75; rotation time: 0.5–0.75 s; tube voltage: 120 kVp; tube current: 34–229 mAs. 100–150 ml iopromide 300 (300 mg I/mL Ultravist, Bayer Pharma, Berlin, Germany) was administered intravenously at a rate of 2–4 ml s⁻¹ after a 30–70 s delay.

All CT scans were performed using volumetric acquisition (16 rows Philips Mx 8000, Philips Medical Systems, Eindhoven, The Netherlands) and a low-dose protocol (120 kV, 40 mAs) with a section collimation of 16 x 0.75 mm, pitch 1.5 and rotation time 0.5 s. The scans were obtained after full inspiration and without the use of contrast. Images were reconstructed with thin (1 mm) sections and a sharp filter algorithm (kernel D) [19 (link)].