Ge advantage workstation 4

FDG PET/CT images were analyzed by two experienced nuclear medicine physicians on a dedicated GE Advantage workstation 4.4 (GE Healthcare). From transaxial PET tomographs of the torso, a SUV threshold-based isocontour method was used to depict the boundaries of each lymphoma lesion. The volumes of interest (VOIs) were automatically drawn around each lymphoma lesion by applying a 41% threshold of the local SUVmax. Volumes were manually edited to remove physiological activity including that of the brain, heart, liver, kidney, and bladder. Mild diffuse bone marrow uptake consistent with reactive hyperplasia was not included. The metabolic tumor volume (MTV) was the summed volume (ml) of voxels with FDG uptake exceeding the threshold. TLG was the sum of the product of MTV and average SUV (SUVave) of all lesions. Our analyses focused on TLG that represents the total quantity of glycolytic tumor tissue rather than MTV that is simply its volume.
Brain FDG uptake was measured from transaxial PET tomographs with the orbitomeatal line as a reference. Volumes of interest (VOIs) were manually placed over bilateral frontal and temporal lobes, and boundaries of cerebral cortices were defined as 40% of maximum activity (Fig. 3a). From these VOIs, SUVave of the frontal and temporal cortices was measured.

Two radiologists with rich experience in the diagnosis of musculoskeletal system imaging read the films. a) DWI: The images were transferred to a GE Advantage Workstation 4.6 to generate ADC images using the MADC calculation. The images with b=800 s/mm² and T2WI images were registered (Fig.1a). The ROI was placed at the largest level of the lesion on the image after registration. The ROI area was about 15-30 mm². The ADC values of the edema area, sclerosis area (Fig.1b), fat deposit area, and normal-appearing bone marrow were recorded as ADC(BME), ADC (sclerosis), ADC (fat deposit) and ADC(NABM), respectively.
b) MT: The viewer function in the GE Advantage Workstation 4.6 was used to analyze the image before applying the pre-saturation pulse (M0) (Fig.1c) and the image after applying the pre-saturation pulse (Ms) (Fig.1d). The ROI was placed in the same place as the ventral articular cartilage in the anterior lower part of the bilateral SIJ. The area was 1-3 mm². The signal intensity of the articular cartilage of the SIJ at the same layer was measured before and after applying the pre-saturation pulse. According to the MTR formula, the magnetization transfer rate of the cartilage (MTRc) was calculated: MTR=(M0-Ms)/M0×100%.

All patients were scanned with the same 64-section dual-energy scanner (GE Discovery CT750HD; GE Healthcare, Milwaukee, WI). Scans were obtained at 25, 55, and 85 s after injection of 100 mL of iopamidol at 3.5 mL/s. The 25 and 55 s acquisitions were acquired in dual-energy rapid 80–140-kVp switching mode using the gemstone spectral imaging protocol [13 (link)]. These were acquired with a GSI preset 1, with a large scan field of view (up to 50 cm), 40-mm beam collimation, 0.6-second rotation time, and 0.984:1 helical pitch, resulting in a maximal tube current of approximately 640 mA. Images were reconstructed into 1.25 mm sections with 25-cm display field of view and 512 × 512 matrix. 70 keV VMIs, the VMI believed to simulate the standard 120 kVp single energy acquisition by extrapolation from abdominal CT studies, were reconstructed and transferred to PACS for interpretation. Source spectral images were transferred to a dedicated workstation (GE Advantage workstation 4.6; GE Healthcare, Milwaukee, WI) where virtual unenhanced image reconstruction or more advanced spectral analysis could be performed.

Volumetric and densitometry measurements were obtained at baseline and at each follow-up CT scan using a dedicated GE Advantage Workstation 4.6 (GE Healthcare, Inc., Waukesha, WI, USA). Volumetric assessment was performed on late arterial phase by manually tracing the lesion margins on each axial slice, with automatic calculation of the total tumor volume, (TTV) (cm³) by the software. The same workstation was used to obtain densitometry measurements by tracing a region of interest (ROI) within the lesion in unenhanced and each post-contrastographic scans. A tumor vascularization index (TVI) was defined by the difference between the average density measured in Hounsfield units (HUs) during the arterial phase in the tumor mass and in non-tumor liver.