Somatom spirit

Each subject was asked to lie in a supine position with knees fully extended so that the patella pointed straight up. Each subject was scanned with a CT scanner (SOMATOM Spirit, Siemens, Germany) from the distal femur to the ankle joint with a slice thickness of 0.5 mm. From the CT images, a 3D model of the PTFJ was constructed for each knee from both groups in Mimics 21.0 (Materialise, Leuven, Belgium). The method for reconstructing the 3D model was validated with cadaveric bone in a previous report by the authors (Zhang et al., 2020 (link)). The models in this current study consisted of a tibia and fibula, while soft tissues including ligaments, cartilage and menisci were excluded.

All CT scans were obtained in the supine position using one of the following scanners: SOMATOM Perspective, SOMATOM Spirit, or SOMATOM Definition AS+ (Siemens Healthineers, Forchheim, Germany). Scans were conducted from the level of the upper thoracic inlet to the inferior level of the costophrenic angle, and images were reconstructed with a slice thickness of 1 or 1.5 mm.
For each patient, predominant CT patterns such as GGO, consolidation, reticulation, emphysema, thickening of the adjacent pleura, pleural effusion, presence of nodules or masses, honeycombing, bronchiectasis, and interlobar pleural traction were independently reviewed by two experienced observers according to the Fleischner Society glossary (21 (link)). CT evidence of fibrotic-like changes was defined as the presence of traction bronchiectasis, parenchymal bands (22 (link)), and/or honeycombing (21 (link), 23 (link), 24 (link)). To quantify the extent of pulmonary abnormalities (GGO, consolidation, reticulation, and fibrotic-like changes), a semiquantitative CT score (25 (link)) was assigned on the basis of the area involved in each of the five lung lobes (right upper, middle, and lower, and left upper and lower lobes): 0, no involvement; 1, <5%; 2, 5–25%; 3, 26–49%; 4, 50–75%, and 5, >75%. Total CT score was calculated by summing the individual lobar scores (possible scores range from 0 to 25).

All chest CT were acquired by using 16- or 64-multidector CT scanners (GE LightSpeed 16, GE VCT LightSpeed 64, GE Optima 680, GE Healthcare; Philips Brilliant 16, Philips Healthcare; Somatom Sensation 64, Somatom AS, Somatom Spirit, Siemens Healthcare). Patients were scanned in the supine position from the level of the upper thoracic inlet to the inferior level of the costophrenic angle with the following parameters: tube voltage of 120 kVp, current intelligent control (auto mA) of 30–300 mA, and slice thickness reconstructions of 0.625–1.5 mm.

Of the eight patients who underwent CT examination, seven underwent plain and contrast-enhanced chest CT images and one underwent non-enhanced CT images alone. The scans were performed using a dual-source CT (Somatom Definition; Siemens Healthcare, Malvern, PA, USA) and a double-slice spiral CT scanners (Somatom Spirit; Siemens Healthcare). The CT parameters were as follows: A tube voltage of 120 kVp, a tube current of 150 mAs, a reconstruction interval of 2 mm, a slice thickness of 2 mm, a field of view of 250–350 mm and a matrix size of 512×512. The contrast-enhanced CT scan was performed with an intravenous injection of 100 ml iopamidol or 80 ml omnipaque at a rate of 2.5 ml/s, administered by a high-pressure autoinjector. CT enhancement was obtained in the arterial and venous phases, 20 and 50 sec after the injection of the contrast agent, respectively. The chest CT images were evaluated by the consensus of two experienced radiologists for the location, shape, size, density, margin and contrast enhancement of the lesions.