Improved Delineation of Pulmonary and Splenic Metastases using FlowMotion Technology
Dustin Osborne, PhD and Yong Bradley, MD, University of Tennessee, Knoxville, TN, USA | 2013-12-01
An 83-year-old male with a history of peripheral vascular disease, aortic aneurysm, myocardial infarction, hypertension and chronic obstructive pulmonary disease presented with altered mental status. Native CT of the brain showed multiple scattered parenchymal lesions with surrounding edema and mild local mass effect consistent with metastatic disease. CT of the thorax confirmed the diagnosis of non-small-cell lung cancer. The patient was referred for PET/CT imaging for primary staging.A PET•CT scan was performed using FlowMotion™* acquisition with variable table speed an hour after an IV injection of 8 mCi of Fludeoxyglucose F 18* (18F FDG). A 3-zone FlowMotion protocol was used, which applied a table speed of 1.5 mm/sec for the head, 0.4 mm/sec in the chest with respiratory gating and 1.5 mm/sec for the abdomen, pelvis and extremities. List mode acquisition with respiratory gating was performed throughout the whole-body acquisition with a slower table speed for the thorax to enable integrated reconstruction of HD•Chest images for the thorax. The whole-body data was initially reconstructed as a whole-body 200x200 matrix reconstruction. Subsequently, the same data was reconstructed using the respiratory gated list mode data with histogramming to define the phases with least motion. The resulting HD•Chest images for the thorax were deemed free of significant respiratory motion. FlowMotion enabled a slower table speed to be used during the chest acquisition, thus ensuring high count statistics and providing high-quality HD•Chest images.
*Siemens' PETNET Solutions is a manufacturer of fludeoxyglucose F 18 injection (18F FDG). Indication and important safety information as approved by the US Food and Drug Administration can be found at the bottom of the page for 18F FDG, adult dose 5-10 mCi, administered by intravenous injection.
The non-gated study showed a hypermetabolic, posteromedial right lung mass, as well as a small focal hypermetabolic lesion in the medial left lower lobe along with multiple mediastinal lymph node metastases. The pulmonary nodule located in the posterior left lung was identified as having only mildly increased 18 F FDG avidity with a max SUV of 2.2 and suffered from significant respiratory motion artifacts measuring approximately 26 mm. There were no significant abdominal, pelvic or skeletal findings except for a large subphrenic space, which appears hypodense on a CT scan that does not show 18 F FDG avidity. HD•Chest images show sharp definition of pleural nodule free of respiratory motion. When SUVmax was measured using HD•Chest reconstructed data, all secondary lesions showed at least a 10% increase in SUVmax with a maximum increase of 46%. A posterior left lung lesion previously identified as having mild 18 F FDG avidity showed a 23% increase in SUVmax to 2.7, placing it above common threshold limits and slightly above liver background of 2.4. The respiratory motion artifacts in this lesion were eliminated with the use of HD•Chest, showing the tumor measurement to be only 11 mm. The HD•Chest images also show two areas of focal uptake in the superior portion of the spleen not visible on conventional whole-body PET. These lesions, previously not seen on CT or conventional PET, showed both had SUVmax values of approximately 2.4 with measurements of 10 mm and 7 mm respectively.
PET/CT confirmed a hypermetabolic primary lung mass with multiple metastases in the mediastinal lymph nodes, opposite lung, pleura and spleen. HD•Chest images sharply defined left-lower-lobe metastases in the lung base, as well as pleural and splenic lesions. HD•Chest reconstruction for the entire thorax with high image quality made possible by Flow- Motion’s variable table speed enabled respiratory gated acquisition with high count statistics due to the ability to precisely define a lower table speed for the thorax and upper abdomen.
Scanner: FlowMotion Technology
Scan Dose: 8mCi (298 MBq/kg) 18 F FDG
Scan Delay: 60 minutes post injection
Parameters: 1.5 mm/sec; 0.4 mm/sec;
*Fludeoxyglucose F 18 Injection
INDICATIONS AND USAGE
Fludeoxyglucose F 18 injection (18F FDG) is indicated for positron emission tomography (PET) imaging in the following setting:
Oncology: For assessment of abnormal glucose metabolism to assist in the evaluation of malignancy in patients with known or suspected abnormalities found by other testing modalities, or in patients with an existing diagnosis of cancer.
IMPORTANT SAFETY INFORMATION
Radiation-emitting products, including fludeoxyglucose F 18 injection, may increase the risk for cancer, especially in pediatric patients. Use the smallest dose necessary for imaging and ensure safe handling to protect the patient and health care worker.
Blood Glucose Abnormalities
In the oncology and neurology setting, suboptimal imaging may occur in patients with inadequately regulated blood glucose levels. In these patients, consider medical therapy and laboratory testing to assure at least two days of normoglycemia prior to fludeoxyglucose F 18 injection administration.
Hypersensitivity reactions with pruritus, edema and rash have been reported; have emergency resuscitation equipment and personnel immediately available.
Fludeoxyglucose F 18 injection is manufactured by Siemens' PETNET Solutions, 810 Innovation Drive, Knoxville, TN 39732
*Biograph mCT Flow is not commercially available in all countries. Due to regulatory reasons its future availability cannot be guaranteed. Please contact your local Siemens organization for further details
**Based on competitive information available at time of publication. Data on file.