Staging of lung cancer. do we need a diagnostic ct of the brain after an integrated pet/ct for the detection of brain metastases?

Abstract

Brain CT has been recommended in staging of patients with lung cancer because of its usefulness in the detection of metastases. Purpose of this study is to examine if a diagnostic brain CT (CT1) can be obviated when an integrated PET/CT (PET/CT ) is available. 87 consecutive patients underwent a diagnostic brain CT and a whole-body PET/CT within a period of 3 weeks to stage a known primary tumour. CT examinations were evaluated by two experienced neuroradiologists on the detection of brain lesions (benign and malignant). The results of PET/CT and CT reading were compared and both readings were compared with the clinical results. Statistical analysis was done by measuring sensitivity, specificity, PPV, NPV and accuracy. The relative accuracies were compared by a McNemar (exact) test for correlated proportions. Considering the CT1 as standard of reference, sensitivity, specificity, PPV, NPV and accuracy for the brain CT of PET/CT (CT2) and PET/CT were respectively 83%, 96%, 77%, 97%, 94% and 69%, 98%, 90%, 95%, 94%. Considering the clinical diagnosis as standard of reference these figures were for CT1, CT2 and PET/CT respectively 80%, 100%, 100%, 96%, 96% and 66%, 95%, 77%, 93%, 90% and 66%, 97%, 83%, 93%, 91%. There was no statistical difference between CT1 and CT2. The comparison of the additional CT in PET/CT with a diagnostic CT of the brain did not yield a statistical difference in the detection of brain lesions despite the inferior quality of the CT component of PET/CT. A diagnostic brain CT can be obviated when a PET/CT is available.

Methods for Staging Non-small Cell Lung Cancer

“…55 However, in one series, the accuracy of integrated PET-CT scanning for brain metastases rivaled that of diagnostic brain CT scanning, and the need for a separate brain CT scan was obviated. 56 But, importantly, others have found that MRI improves detection when added to PET-CT scanning. 57 Biannual follow-up MRI may detect early brain metastases, thereby providing opportunities for radiosurgery.…”

Integrated PET/CT in the Staging of NSCLC

“…The observation of distant metastases in patients with NSCLC has major implications for management and prognosis. In total, 40% of patients with NSCLC have distant metastases at presentation, most commonly in the adrenal glands, bones, liver or brain [46,47]. After radical treatment for seemingly localized disease, 20% of these patients develop an early distant relapse, probably due to systemic micro-metastases that were present at the time of initial staging [48].…”

Functional Dynamic Contrast-Enhanced Magnetic Resonance Imaging in an Animal Model of Brain Metastases: A Pilot Study

“…Of the available diagnostic methods for brain metastases, imaging modalities play an important role in non-invasive diagnosis and treatment management [1] , [3] , [6] – [9] . Computed tomography (CT) has been widely used in the diagnosis, staging, monitoring, therapeutic effect evaluation and follow-up due to its accessibility and affordability [6] , [7] . Routine cranial CT and contrast-enhanced CT (CECT) can delineate lesions for larger tumor metastases.…”

“…However, for small metastases or those located in special locations, such as the posterior fossa, CT cannot achieve ideal delineation. Studies have shown that both routine CT and CECT have a limited sensitivity, which is approximately 80% [6] . Positron emission tomography (PET) and its hybrid integrated image techniques, including PET/CT and PET/magnetic resonance imaging (MRI), are now important imaging modalities for diagnosis and staging as well as for providing prognostic information based on the response to treatment [9] – [11] .…”