الفهرس 
PathologyOnly 14 pages are availabe for public view
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Abstract
This study included 70 patients ranging in age from 3 to 72 years with mean age 39.3 16.85. They were 40 males and 20 females. Forty patients had mediastinal lesions, 20 had lung lesions and 10 had chest wall and pleural lesions.
All of them had CT chest showing mass lesion and were sent to radiology department to do MRI before CT guided or surgical biopsy. Diffusion weighted MRI was done for all patient with ADC map reconstruction and measuring of ADC value. Dynamic contrast enhanced MRI was done for only 30 patients with anterior mediastinal mass and TIC was reconstructed.
The mediastinal lesions were 24 malignant lesions in 24 patients and 20 benign lesions in 16 patients. The mean ADC value for the malignant lesions was 1.10± 0.24 x 10-3 mm2/s while the mean ADC value for the benign lesions was 1.73± 0.55 x 10-3 mm2/s. Comparison between the mean ADC value of the benign and malignant mediastinal lesions was highly significant with P value <0.001.
The receiver operator curve (ROC) analysis showed that the cutoff point of the ADC value differentiating malignant mediastinal tumors from benign mediastinal lesions was 1.23 x 10-3 mm2/s with sensitivity of 91.7%, specificity of 90%, PPV of 91.7%, NPV of 90% and accuracy of 90.9%.
At Dynamic contrast MRI the time intensity curve (TIC) was persistent (Type I) in 7 lesions, plateau (Type II) in 14 lesions and washout (Type III) in 9 lesions. Type III washout curve was seen only in thymic epithelial tumors.
The twenty pulmonary lesions were 14 malignant lesions and 6 benign lesions. The mean ADC value of malignant lesions was 1.33±0.30 x10-3 mm2/sec and mean ADC value for benign lesions was 2.19±0.78 x10-3 mm2/sec. There was significant difference between mean ADC value of malignant and benign pulmonary lesion with p value=0.003.
The mean lesion to cord ratio (LCR) was 1.37±0.47 for malignant lung lesions and 0.59±0.09 for benign ones. The difference between mean LCR of malignant and benign pulmonary lesions was highly significant (p<0.001).
Using a cutoff value of 1.13x10-3 mm2/sec, the ADC showed sensitivity of 85.7%, specificity of 83.3%, positive predictive value of 92.3%, negative predictive value of 71.4%, and an accuracy of 85 % in the detection of cancer lesions. However, by using a cutoff value of 0.81, the LCR had sensitivity of 92.9%, specificity of 90%, positive predictive value of 90%, negative predictive value of 85.7%, and an accuracy of 91 % for the detection of lung malignancies.
The 10 chest wall and pleural lesions were 6 benign and 4 malignant. The mean ADC value for benign lesions was 1.68 ±0.17 x10-3 mm2/s and mean ADC value for the malignant lesion was 1.24 ±0.19 x10-3 mm2/s. The mean ADC value of the malignant lesions was significantly different from mean ADC value of benign lesion with p < 0.001.