PET-CT TUMOR IMAGING SKULL BASE TO THIGH, PET-BRAIN POST WB (COUNT/NR)

CLINICAL INDICATION: The patient is a 57-year-old male with a history of sigmoid resection in 2007 4 moderately differentiated adenocarcinoma. Fine-needle aspiration of a rectal mass performed on 20/2/2014 demonstrated adenocarcinoma. The patient completed chemoradiation 2/20/2015 followed by colectomy 4/10/2015 or there was no evidence of malignancy in the rectum or sigmoid colon and no evidence in the sampled lymph nodes. Tissue from the left lateral wall did demonstrate malignant glandular cells. PET/CT is requested for restaging.

COMPARISON: CT of the thorax/abdomen/pelvis 3/11/2016, MRI of the abdomen 1/8/2015, CT of the abdomen/pelvis 11/10/2014

TECHNIQUE: The patient was studied in a fasting state and 11.5 mCi of fluorine 18 labeled deoxyglucose was given intravenously. The patient's blood sugar was 98 mg/dL at the time of injection. Approximately 60 minutes post injection, tomographic imaging from the vertex through the thighs was performed. A low dose CT scan was acquired for attenuation correction and anatomic localization of the PET images. The CT scan portion of the study is not for diagnostic purposes. No contrast agent was given and no breath hold technique was performed. A separate referral should be made if a diagnostic CT is required.

FINDINGS: There is normal FDG uptake seen throughout the cerebrum, cerebellum, and basal ganglia without focal abnormality in the brain. High physiologic background FDG uptake within the cortical gray matter limits the sensitivity of PET for detection of metastatic disease in the brain.

There is no evidence of malignancy seen in the nasopharynx, oropharynx, larynx, or bilaterally in the cervical and supraclavicular regions. The thyroid gland is grossly normal in appearance.

Normal FDG uptake is seen bilaterally in the lungs without evidence of hypermetabolic or noncalcified nodules. A subcentimeter calcified granuloma is seen in the right lower lobe. There are no pleural pericardial effusions. There is no evidence of malignancy seen in the mediastinum, bilateral hilar regions, bilateral axillary regions, or throughout the remainder of the thorax and bilateral upper cavities. Non-FDG avid calcified right hilar and mediastinal lymph nodes are consistent with a history of granulomatous disease. A chemotherapy port is seen in the right anterior chest wall with a right internal jugular central venous catheter tip ending in the SVC. Multivessel coronary calcifications are noted.

There is no evidence of malignancy seen in the stomach, liver, spleen, pancreas, adrenals, or abdominal, pelvic, and inguinal nodal stations. A right pleural calcified mass demonstrates no increased FDG uptake is unchanged when compared to prior studies, most consistent with a benign process. Punctate calcifications within liver and spleen are consistent with prior history of granulomatous disease. Postsurgical changes are seen consistent with a recent ventral abdominal incision and hemicolectomy. Mild increased FDG uptake is seen surrounding the sutures in the rectal stump an ileostomy is seen in the left lower quadrant.

Normal FDG uptake is seen throughout the visualized osseous structures without suspicious sclerotic or lytic lesions on CT to suggest evidence of osseous malignant involvement.

Impression
1. There is no definite evidence of malignancy.
2. Mild FDG uptake surrounding sutures in the rectal stump are within the limits of inflammatory postoperative changes, however a small component of residual viable malignancy cannot be completely excluded and attention is recommended this region on followup studies.