TUMOR FDG-PET/CT IMAGING
EXAMINATION: TUMOR FDG-PET/CT IMAGING
SCANNER: Biograph mCT flow PET/CT
RADIOPHARMACEUTICAL: 9.9 mCi F-18 Fluorodeoxyglucose (FDG) I.V.
HISTORY: 43 – year – old male with intra-abdominal leiomyosarcoma. S/P laparotomy exploration and removal of tumor on 10/7/2018, followed by 2 cycles of chemotherapy.
Restaging CT dated 17/9/2018 showed peripherally enhancing rounded necrotic residual lesion in the left upper quadrant has decreased from 6.3 x 5.4 cm to 4.8 x 3.6 cm, and stable multiple (at least 5) hypodense hepatic lesions in both liver lobes measuring up to 2.5 x 2.3 cm. The study is requested for restaging , and monitoring response to therapy.
TECHNIQUE: The patient fasted for more than 6 hours. His fasting blood glucose level, measured by glucometer before injection of FDG, was 79 mg/dL. While he lay quietly in a room Plain water (1.2 L) was given as a negative contrast after the FDG injection. A low dose – noncontrast CT scan was acquired for attenuation correction and for fusion with emission PET images to allow for anatomical localization of PET findings, and not for diagnostic purposes. Emission PET images were then obtained. The area imaged spanned the region from the skull vertex to the proximal thighs with the arms positioned above the head. The time from injection of FDG to start of imaging was 40 minutes. Transverse image reconstruction using an iterative algorithm was performed with reoriented tomograms displayed in the transaxial, coronal and sagittal planes.
ABDOMEN AND PELVIS:
- 1walled hypodense left hydrochondrial mesenteric cystic lesion noted abutting the wall of splenic flexure of colon. It measures about 4.4 x 3.4 cm and showed only mild peripheral FDG-avidity at its thick wall (SUV max of about 2) with cold non-FDG-avid center.
- 2Preexisting multiple hypodense hepatic lesions noted at both liver lobes, currently has no corresponding pathological FDG-avidity, probably benign i.e. hemangioma.
- 3Mildly FDG-avid midline upper anterior abdominal wall healing surgical scar noted.
- 4The Spleen, pancreas, and adrenal glands are unremarkable regarding any pathological FDG avid lesions.
- 5Both kidneys showing physiological FDG excretion that drains into urinary bladder.
- 6The stomach and bowel show physiological FDG-activity.
- 7There is no sizable FDG-avid lymphadenopathy seen in the abdomen and pelvis
HEAD AND NECK:
- 1On the PET study, physiological FDG activity in the surveyed parts of brain gray matter is noted
- 2Bilateral FDG uptake in the medial and lateral rectus extraoccular muscles, and mylohyoid muscles which is physiological in nature.
- 3Foci of brown fat uptake noted at the neck
- 4Diffuse physiological FDG uptake is noted in the soft palate, tonsils, parotid, submandibular salivary glands, and vocal cords.
- 5No significant FDG-avid sizable cervical or supraclavicular lymph nodes, apart from few small, mildly FDG avid likely reactive nodes.
- 6FDG-avid hypodense right thyroid lobe nodule measures about 1 x 0.7 cm cm and has SUV max of 5.97 noted.
- 1The chest wall is devoid of any metabolic activity or sizable FDG avid pathological lesions
- 2Both lung fields show unremarkable FDG metabolic activity, with no FDG-avid sizable lung nodules.
- 3No FDG-avid sizable lymphadenopathy in the mediastinal, hilar or axillary regions.
- 4Physiological uptake is seen in the myocardium.
- 1There are no FDG-avid osseous lesions at the surveyed parts of the skeleton.
- 2Non-FDG-avid few small sclerotic densities noted both iliac wings and neck of left femur, probably benign bone islands for follow up.
The current PET/CT study demonstrates: