Évaluation par la TEMP–TDM des lésions classées indéterminées en scintigraphie osseuse chez les patients de cancérologie

Abstract

The aim of the present study was to investigate the contribution of the single photon emission computed tomography/computed tomography (SPECT/CT) in cancer patients and to evaluate its ability to correctly classify indeterminate lesions on planar bone scintigraphy (PBS). Methods From November 2006 to August 2007, all patients with confirmed malignancy, whose PBS showed indeterminate lesions, underwent without delay a SPECT/CT. The study included 120 patients (67 men, 53 women), with a mean age of 69 ± 12 years (range 42–96 years). The patients with obvious metastases, important pains or who did not accept the examination were excluded from the study. The location of the lesions was described either as precise, probable or indeterminate. The lesions were classified either as definitely malignant, definitely benign or indeterminate. Results Breast, prostate, lung and kidney neoplasms represented approximately 80% of all cancers. The PBS highlighted 267 lesions of location either as precise ( n = 29), probable ( n = 129) or indeterminate ( n = 109), classified either as definitely malignant ( n = 28), definitely benign ( n = 27) or indeterminate ( n = 212). The SPECT/CT revealed 440 lesions, of location either as precise ( n = 353), likely ( n = 39) or indeterminate ( n = 48), classified either as definitely malignant ( n = 84), definitely benign ( n = 305) or indeterminate ( n = 51). Thoracic and lumbar spine and pelvis were the locations of 79% of the scintigraphic lesions and of 88% of the osseous metastases. SPECT/CT modified the final report of 80 patients, by excluding from metastases ( n = 2), by showing metastases ( n = 23) and by showing the benign character of indeterminate lesions ( n = 55). Moreover, 69 patients out of 120 (> 57%) had an evolution confirmed with 35 true positives, 31 true negatives, one false negative and two patients with indeterminate lesions on SPECT/CT, without osseous metastasis. Conclusion The assessment of the indeterminate scintigraphic lesions of oncologic patients benefits from the SPECT/CT. The lesion-based analysis showed that the SPECT/CT detected more lesions (+64%) and correctly classified 88% of the detected lesions. The patient-based analysis highlighted that SPECT/CT modified the final report for more than 66% of the patients. The follow-up showed that SPECT/CT correctly classified for more than 95% of the patients.