64 slice spiral ct scanner

All patients received cardiac CT scans using the 64-slice spiral CT scanner (General Electric Healthcare, Milwaukee, WI, USA). The scan was electrocardiogram gated and began when the heart rates of patients were less than 70 times/min according to the protocol with a tube voltage of 120 kVp, tube current of 80 mA, 3.0 mm slice thickness, and displayed field of 1.5. Calcium deposits in the coronary arteries were independently identified by two radiologists with level 2 competence and over 9 years of experience in performing cardiac CT. The degree of CAC was reflected by CAC scores expressed in Agatston units (AUs) [23 (link)]. Total CAC scores were calculated after summing the CAC scores of the left main artery, the left anterior descending artery, the left circumflex artery, and the right coronary artery. The MHD patients with CACs <100 were arranged into the mild group, those with 100–400 CACs into the moderate group, and those with CACs >400 into the severe group.

Preoperative non-contrast (NC) and contrast-enhanced CT scans were performed for each patient at the two institutions. Institution I performed CT scans using two CT scanners: a 64-slice spiral CT scanner (Siemens, Germany) or a 256-slice spiral CT scanner (Philips, Netherlands). Institution II performed CT scans using four CT scanners: a 16-slice spiral CT scanner (Siemens, Germany), a 64-slice spiral CT scanner (GE, USA), a 64-slice spiral CT scanner (Toshiba, Japan), or a 256-slice spiral CT scanner (Philips, Netherlands).
The parameters for the CT scan were as follows: tube voltage, 100 or 120 kV; tube current, 180–400 mA·s; reconstruction section thickness, 1.25–5.00 mm; pitch, 0.97–1.5; and matrix, 512×512. The scan range was from the skull base to the subclavian region. After routine plain CT scans, contrast-enhanced CT scans were performed after a delay of 20–30 s (arterial phase [AP]) following an intravenous administration of 80–100 mL of iodinated nonionic contrast agent at a rate of 3.0–3.5 mL/s using a high-pressure syringe. The nonionic contrast agent used was iohexol (Yangtze River, China; GE Healthcare, Ireland).

All chest CTs were taken within 24 hours after being admitted to the hospital. When available, CT scans were compared to baseline images to determine the presence of new abnormalities. CT scans were conducted on a 64-slice spiral CT scanner (GE, USA) at 120 kV, automated mAs, and a reconstructed slice thickness of 1.25 mm. Coronal and sagittal reformations were made available. All chest CT images were reviewed retrospectively by two pulmonary radiologists with ten years of expertise. Consensus was established on the final judgments. The Fleischner Society Nomenclature Committee descriptors were used to interpret radiographic CT scans: ground-glass opacities, consolidation, reticular opacities, nodular opacities, and lymphadenopathy. The abnormalities were distributed unilaterally and bilaterally. The presence of an air bronchogram, thickening of the adjacent pleura, and pleural effusions were noted.