F18-FDG whole body positron emission tomography with CT scan

Department of Nuclear medicine and Molecular imaging

Whole body PET CT scan was done following intravenous administration of F18 - FDG. Imaging was perfomed on an integrated Phillips True flight select time of Flight PET scanner with 40 slice/sec Multidetector Computerised Tomography (MDCT), scanning from eyes to mid-thigh. A separate sequence with breath hold was perfomed for lung and a delayed series for brain examination. A semiquantitative analysis of FDG uptake was performed by calculating SUV corrected for dose administered and patient body weight. The blood sugar at the time of tracer injection was 98 mg/dl. The uptake time was 90 mins.

Indication: Patient is being evaluated for right thoracic mass. PET CT scan is being done for pretreatment evaluation.

The overall bio distribution of FDG is within normal physiological limits.

Brain: the supra and infra tentorial brain parenchyma appears unremarkable. There is no ICSOL seen. The ventricular system appears normal. The brain parenchyma demonstrates normal FDG uptake.

Head and Neck: Both lobes of the thyroid gland appear normal in size and demonstrate physiological FDG uptake. Rest of head and neck structures appear unremarkable. There is no FDG avid cervical lymphadenopathy seen.

Thorax: The heart and mediastinal vascular structures appear normal. The trachea and both main bronchi appear normal.

A large lobulated soft tissue attenuation mass lesion is noted in right side of mediastinum which measures approximately 13.0 (AP) x 13.2 (TS) x 17.5 (CC) cm in size and shows mild FDG uptake (SUV Max: 3). Anteriorly the mass is reaching upto the anterior chest wall and posteriorly is reaching upto the paravertebral location. The mass shows heterogenous post contast enhancement likely due to necrosis and is causing mass affect on mediastinal great vessels and heart. Mediastinal shift is noted towards left. The mediastinal mass is compressing the right upper, middle and lower lobar bronchus which appear draped around the mass with subsegmental atelectasis of middle and lower lobes seen. There is infiltration of lateral chest wall seen with cortical erosion of 5th and 6th ribs with evidence of periosteal reaction seen. Rim of right pleural effusion is noted. A mildly FDG avid pleural based nodule is noted along right upper lobe coastal pleural measuring 1.5 x 1.6 cm in size. Rest of bilateral lung fields appear unremarkable. Minimal pericardial effusion is noted.

Abdomen: The liver appears normal in size. The hepatic parenchyma demonstrates normal attenuation. The intra hepatic biliary radicals are not dilated. The portal vein is normal. No abnormal FDG accumulation is seen in the liver parenchyma.

Spleen, Pancreas and both Adrenal glands appear normal in bulk and demonstrate physiological FDG uptake.

There is no FDG avid abdominal or retroperitoneal lymphadenopathy noted.

Bilateral kidneys appear normal in size. Bilateral ureters are defined. Urinary bladder is normal in shape, size and distention. The stomach is well distended with the orally administerd contrast media. The small and large bowel loops appear normal in caliber and fold pattern and shows physiological FDG uptake. The prostate appears unremarkable. Bilateral testicles appear unremarkable and show physiological FDG uptake. There is no pelvic lymphadenopathy seen.

Skeleton: Non FDG avid focal sclerosis is noted in left iliac bone. Degenerative changes are noted in the spine. Rest of the bones under survey appear normal and ahow normal FDG uptake.

Opinion: PET CT scan findings are suggestive of mildly FDG avid right sided mediastinal mass causing mass effect on mediastinal vessels, causing mediastinal ghift and causing compressive subsegmental atelectasis of right lung segments as detailed above with mildly FDG avid pleural based nodules along right upper lobe and rim of right pleural effusion. There is an absence of FDG avid disease in rest of the body survey. Please correlate clinically.