Clinical History

The patient is a 35-year-old male who was first diagnosed with bronchial carcinoid tumor of the left upper lobe in 1991. This tumor is now thought to be recurrent and we have been asked to rule out other sites of disease prior to external beam radiation therapy.

Technique

The patient received an intravenous injection of 10 millicuries of F18 FDG and 45 minutes later whole body PET imaging was carried out from the upper cervical region to the upper femoral region. Coronal, axial, sagittal, volume displays were created and regions of interest placed about selected regions for the measurement of standard uptake values (SUV).

Findings

There is diffuse radiotracer accumulation throughout the posterior left hemithorax extending from apex to diaphragm. The maximum SUV of this rather uniform increase in activity is 1.7. Using current technique and equipment, this SUV is related to inflammatory rather neoplastic origin. Imbedded this somewhat uniform inflammatory background are three focal regions of increased FDG uptake. The most inferior focus is approximately 5 cm in the craniocaudal direction with a generally basically vertical orientation and is approximately 2 cm in the lateral dimension and 2 cm in the AP direction. The SUV of this site is 3.1. The second focus is slightly superior and medial to the previously-mentioned site. It is approximately 2 cm in diameter with an SUV of 2.5. Superior and medial to the second site and approximately 4 cm superior to the first mentioned site is another focus of activity with an SUV of 2.7. Also it has approximately a 2 cm diameter. The liver and adrenals are free of obvious metastasis. There is, however, a region of focal uptake measuring 3 cm in the superior inferior direction, 2 cm laterally and 3 cm in the AP direction with an SUV of 7.0. This occurs at the intersection of coronal 68, axial 120, and sagittal 58. It is just anterior and to the right of the inferior aspect of the L5 vertebra. It has an SUV of 7.0. This is probably a site of focal neoplasia as it appears the ureter can be identified as a separate structure in that vicinity.

Impressions

1.THREE FOCI OF ACTIVE NEOPLASIA ARE IDENTIFIED IN THE POSTERIOR AND INFERIOR ASPECT OF THE LEFT HEMITHORAX IMBEDDED THE INFLAMMATORY CHANGES CONSISTENT WITH A PRIOR LEFT LOWER LOBE PNEUMONECTOMY.
2.THERE IS A HIGHLY SUSPICIOUS REGION OF INCREASED FOCAL TRACER RETENTION AT THE LEVEL OF THE INFERIOR ASPECT OF L5 VERTEBRA JUST ANTERIOR AND TO THE RIGHT OF THE L5 VERTEBRA. THIS IS THOUGHT TO BE DISTINCT FROM THE URETER. A MASS IN THIS REGION COULD NOT BE IDENTIFIED ON THE ACCOMPANYING ABDOMINAL CT'S. ACTIVE TUMOR NEOPLASIA IN THIS REGION IS SUSPECTED.
3.SUV'S OF GREATER THAN 2.3-2.5 ARE MORE LIKELY TO BE ASSOCIATED WITH ACTIVE NEOPLASIA. VALUES BELOW THOSE FIGURES ARE MORE LIKELY TO BE ASSOCIATED WITH INFLAMMATORY CHANGE.

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