The importance of diffusion apparent diffusion coefficient values in the evaluation of soft tissue sarcomas after treatment.

PURPOSE: In our study, we aimed to show the efficiency of diffusion-weighted images at different b-values and apparent diffusion coefficient (ADC) values in the differentiation of recurrent tumours from post-treatment tissue changes. MATERIAL AND METHODS: The conventional and diffusion magnetic resonance images (MRIs) of 42 patients operated for soft tissue sarcomas between June 2012 and March 2015 followed up with MRIs that were evaluated by 2 radiologists retrospectively. Diffusion MRIs were acquired at 4 different b-values (50, 400, 800, 1000 s/mm2). The lesions were classified according to conventional MRI findings as post-treatment changes and recurrent tumours. RESULTS: When the patient group with recurrent tumours was compared with the patient group with postoperative changes the ADC calculations were statistically significantly lower for the recurrent tumours at all b-levels (p < 0.001 for all b-levels). The sensitivity of b-50 values lower than 3.01 × 103 mm2/s in showing recurrent tumours was 100% and the specificity was 77.78%. The sensitivity of b-400 values lower than 2.1 × 103 mm2/s in showing recurrent tumours was 80% and the specificity was 96.3%. The sensitivity of b-800 values lower than 2.26 × 103 mm2/s in showing recurrent tumours was 100% and the specificity was 88.89%. The sensitivity of b-1000 values lower than 2 × 103 mm2/s in showing recurrent tumours was 93.3% and the specificity was 92.5%. CONCLUSIONS: The ADC values obtained from diffusion-weighted images have high sensitivity and specificity in differentiating recurring soft tissue sarcomas during monitoring after treatment from postoperative changes.

Diffusion weighted magnetic resonance imaging in the diagnosis of parotid masses. Preliminary results.

OBJECTIVE: To demonstrate the diagnostic potentials of MRI, diffusion weighted imaging (DWI), and apparent diffusion coefficient (ADC) mapping in the detection of parotid masses correlated to the histopathological results. Methods: Study design was retrospective. Fifteen patients with parotid gland masses were included as the study group and contralateral normal parotis glands of same patients were taken as the control group. Patients with bilateral parotid gland tumors were excluded, 7 right-sided and 8 left-sided parotid masses were included in the research. The study took place at the Department of Radiology, Ankara, Turkey, between May 2012 and September 2014. Results: Apparent diffusion coefficient measurements of 15 parotis tumors in 1000 and 750 sec/mm2 b-values with comparison to the contralateral normal gland  parenchyma were demonstrated. Neurofibromas was predicted as the highest, and lipomas as the lowest ADC values. Pleomorphic adenomas, Warthin's tumor, and normal parotid parenchyma indicate significant statistical differences from each other on the basis of mean ADC values (p less than 0.05). Conclusion: The DWI and ADC mapping of parotis gland could aid in the differential diagnosis  of benign and malignant masses.

Imaging of Cystic and Cyst-like Lesions of the Mediastinum with Pathologic Correlation.

Cystic masses of the mediastinum are a heterogenous group of asymptomatic or symptomatic, congenital, infectious, or neoplastic lesions. For early and correct diagnosis, evaluation, and optimal patient management of cystic mediastinal masses in infants, children, or adults imaging plays an important role. A non-invasive and sensitive imaging modality is an efficient and cost-effective tool. Multidetector computed tomography (MDTC) with volumetric acquisition provides fast acquisition of high resolution images and multiplanar reconstruction. Both 2D and 3D imaging in mediastinal imaging help in surgical planning and assessing resectability of mediastinal lesions. MR imaging has many advantages over other modalities for detecting and identifying cystic, or fluid-filled mediastinal masses, because of its intrinsic high soft tissue contrast and direct multiplanar imaging capabilities. However, histological tissue analysis may be required to differentiate a cystic lesion from other cyst-like or low-attenuation lesions.