Oleg Blagosklonov MD, Presenter: Nothing to Disclose

Réka Zsigmond, Abstract Co-Author: Nothing to Disclose

Orland Angoue, Abstract Co-Author: Nothing to Disclose

Jean-François Bonneville MD, Abstract Co-Author: Nothing to Disclose

Jean Claude Cardot, Abstract Co-Author: Nothing to Disclose

Hatem Boulahdour MD, PhD, Abstract Co-Author: Nothing to Disclose

The value of delayed or dual-time-point (2 to 3 hours after the injection) FDG-PET imaging for detection of abdominal lesions is well-established. Recent reports showed that very delayed acquisition (6 hours after the injection) may be useful for delineation of gliomas from gray and for detection of cerebral lymphoma. We generalized this technique to all cerebral FDG-PET scans performed in our department.

After 6-hours fasting, a dose of 4 to 5 MBq/kg of FDG was administered intravenously. The PET images were acquired twice (1h and 6 h after the injection) using a PET/CT device (Siemens Biograph Duo, CTI, Knoxville, TN). The CT scan was performed in a spiral mode with 2mm slice thickness. Then, the FDG images were acquired with an axial field of view of 12 cm (15 min/bed). From January 2005 to march 2007, 58 cerebral FDG-PET scans were performed in 44 patients with following diagnosis: cerebral metastasis suspected on MRI (15), glioma (12), pituitary adenoma or Cushing’s syndrome (6), epilepsy (4), cerebral lymphoma (2), and unknown (5).

Standard 1-hour PET scan showed no lesion in 1 case, one or more high-uptake lesions in 18 cases, and one or more low-uptake lesions in 39 cases. The delayed acquisition revealed additional 11 high-uptake lesions, not visible on the standard PET images, allowing the detection of 6 recurrent cerebral metastasis, 3 high-grade gliomas, 1 pituitary microadenoma, and 1 focus of epilepsy. We observed enhanced contrast between grey matter and hypermetabolic as well hypometabolic lesions on the delayed PET images.

Our results proved clinical importance of very delayed cerebral FDG-PET scan. We consider that the value of this easy-to-perform and well-accepted technique is comparable to that of FGD-PET scan without attenuation correction in lung cancer diagnosis.

Very delayed cerebral FDG-PET scan can reveal hypemetabolic and hypometbalic lesion in oncological and non-oncological patients.

Blagosklonov, O, Zsigmond, R, Angoue, O, Bonneville, J, Cardot, J, Boulahdour, H, Very Delayed Cerebral FDG-PET Imaging.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5001400.html