ABSTRACT
PURPOSE: To determine whether parameters generated by Dual-Energy Computed Tomography (DECT) can distinguish malignant from benign lung lesions. METHODS: A prospective review of 125 patients with 126 lung lesions (23 benign and 103 malignant) who underwent lung DECT during arterial phase. All lesions were confirmed by tissue sampling. A radiologist semi-automatically contoured lesions and placed regions of interest (ROIs) in paravertebral muscle (PVM) for normalization. Variables related to absorption in Hounsfield units (HU), effective atomic number (Zeff), iodine concentration (ρI) and spectral CT curves were assessed. Receiver operating characteristic (ROC) curves were generated to calculate sensitivity and specificity as predictors of malignancy. Multivariate logistic regression analysis was performed. RESULTS: Reproducibility of measures normalized with PVM was poor. Bivariate analysis showed minimum Zeff and normalized mean Zeff to be statistically significant (p=0.001), with area under the curve (AUC) values: 0.66 (CI 95% 0.54-0.80) and 0.72 (CI 95%, 0.60-0.84), respectively. Logistic regression models showed no differences between raw and normalized measurements. In both models, minimum HU (OR: 0.9) and size (OR: 0.1) were predictive of benign lesions. CONCLUSIONS: A quantitative approach to DECT using raw measurements is simpler than logistic regression models. Normalization to PVM was not clinically reliable due to its poor reproducibility. Further studies are needed to confirm our findings.
Subject(s)
Lung Neoplasms/diagnostic imaging , Lung/diagnostic imaging , Multidetector Computed Tomography , Radiographic Image Interpretation, Computer-Assisted , Adult , Aged , Aged, 80 and over , Diagnosis, Differential , Female , Humans , Image Processing, Computer-Assisted , Lung/pathology , Lung Neoplasms/pathology , Male , Middle Aged , Prospective Studies , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is characterized by asymmetrical and poorly defined growth. Magnetic resonance imaging (MRI) has been proposed for the delimitation of this tumor. OBJECTIVES: To study the utility of MRI in evaluating the depth of infiltration in DFSP and to compare the efficiency of clinical palpation with that of MRI in delimiting the invasiveness of DFSP. METHODS: Observational, prospective study of DFSP cases. The MRI scans for all cases were compared with the exact histological infiltration plane obtained using modified Mohs micrographic surgery (MMS). RESULTS: Forty-three DFSPs were included: 22 primary, nine recurrent, and 12 extirpated with positive margins. Sensitivity for detecting deep invasion was 58% on examination using palpation and 67% using MRI. CONCLUSIONS: We present the largest series of DFSP cases studied using MRI published to date. In primary cases, MRI has greater sensitivity than palpation for detecting depth of infiltration (67% vs 58%). MRI seems to be useful in primary DFSP in locations other than the head, neck, and upper part of the thorax. MRI is not useful for confirming tumor persistence in extirpated DFSP with positive margins or for studying lateral extension in primary DFSP.
