Abstract
BackgroundBrain metastases (BM) are the most common intracranial tumors in adults outnumbering all other intracranial neoplasms. Positron emission tomography combined with computed tomography (PET/CT) is a widely used imaging modality in oncology with a unique combination of cross-sectional anatomic information provided by CT and the metabolic information provided by PET using the [18F]-2-fluoro-2-deoxy-d-glucose (FDG) as a tracer. The aim of the study is to assess the role and diagnostic performance of brain-included whole-body PET/CT in detection and evaluation of BM and when further imaging is considered necessary. The study was conducted over a period of 12 months on 420 patients suffering from extra-cranial malignancies utilizing brain-included whole-body PET/CT.ResultsThirty patients with 71 brain lesions were detected, 18 patients (60%) had BM of unknown origin while 12 patients (40%) presented with known primary tumors. After brain-included whole-body FDG-PET/CT examination, the unknown primaries turned out to be bronchogenic carcinoma in 10 patients (33.3%), renal cell carcinoma in 2 patients (6.7%), and lymphoma in 2 patients (6.7%), yet the primary tumors remained unknown in 4 patients (13.3%). In 61 lesions (85.9%), the max SUV ranged from 0.2- < 10, while in 10 lesions (14.1%) the max SUV ranged from 10 to 20. Hypometabolic lesions were reported in 41 (57.7%) lesions, hypermetabolic in 3 lesions (4.2%), whereas 27 lesions (38.0%) showed similar FDG uptake to the corresponding contralateral brain matter. PET/CT overall sensitivity, specificity, positive and negative predictive, and accuracy values were 78.1, 92.6, 83.3, 90, and 88% respectively.ConclusionBrain-included whole-body FDG-PET/CT provides valuable complementary information in the evaluation of patients with suspected BM. However, the diagnostic performance of brain PET-CT carries the possibility of false-negative results with consequent false sense of security. The clinicians should learn about the possible pitfalls of PET/CT interpretation to direct patients with persistent neurological symptoms or high suspicion for BM for further dedicated CNS imaging.
Highlights
Brain metastases (BM) are the most common intracranial tumors in adults outnumbering all other intracranial neoplasms
Patients presented with systemic metastases along with BM were 16 patients (53.3%) and detected as bony, nodal, lung, suprarenal, hepatosplenic, and subcutaneous deposits while 14 patients (46.7%) presented with BM without systemic metastases
These results showed that bronchogenic carcinoma was the most common primary tumor both in the previously diagnosed patients and as more commonly presenting metastases of unknown origin
Summary
Brain metastases (BM) are the most common intracranial tumors in adults outnumbering all other intracranial neoplasms. The study was conducted over a period of 12 months on 420 patients suffering from extra-cranial malignancies utilizing brain-included whole-body PET/CT. Brain metastases (BM) are the most common intracranial tumors in adults outnumbering all other intracranial tumors [1, 2]. The biological characteristics of the tumors are expected to affect the spatial distribution of their BM by a theory called “seed and soil.”. This theory suggested a non-random distribution of metastases by special tumor cell properties and variances in microenvironments of different organs [8, 9]. BM in systemic cancers portends poor prognosis with a median survival of less than 6 months [12]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call