Diffusion-weighted MRI in cervical lymph nodes: differentiation between benign and malignant lesions.

OBJECTIVE: Purpose of our study was to assess the potential role of diffusion-weighted imaging (DWI) in the differential diagnosis between benign and malignant nodes. SUBJECT AND METHODS: We enrolled 32 subjects: 14 with benign lymphadenopathy, 17 patients with histologically proved malignant disease before beginning treatment and 1 patient with lymphoma after chemotherapeutic treatment. In all patients we used fast spin echo T2-weighted images in axial and coronal planes, fast spin echo T1-weighted images before and after contrast medium of administration in axial and coronal planes. Before contrast administration diffusion sequences were acquired on the axial and coronal plane (b factor of 0.500 and 1000 s/mm(2)) and then apparent diffusion coefficient (ADC) maps were reconstructed. RESULTS: On diffusion images, 13/14 patients with benign nodes showed low signal intensity and had high signal on ADC maps, whereas all patients with malignant diseases appeared hyperintense on diffusion images and with low signal intensity on ADC maps. Only a patient with tuberculosis showed a low ADC value. The mean ADC value of malignant nodes was about 0.85 × 10(-3)mm(2)/s, the mean value of benign nodes was 1.448 × 10(-3)mm(2)/s; this difference was statistically significant (p < 0.01). The mean ADC value of treated nodes was 1.75 × 10(-3)mm(2)/s. The best threshold value was 1.03 × 10(-3)mm(2)/s, obtaining a sensitivity of 100% and a specificity of 92.9%. CONCLUSIONS: Diffusion imaging could be considered an important supportive tool for the diagnosis of enlarged cervical lymphadenopathies.

Diffusion-weighted MR imaging and apparent diffusion coefficient of the normal fetal lung: preliminary experience.

OBJECTIVE: To assess if a correlation is present between apparent diffusion coefficient (ADC) values and normal lung maturation during gestation to define potential reference values as indicators of the lung development. METHODS: Our study included 50 pregnant women (gestational age, GA: 18-36 weeks), with normal fetal development of lungs assessed by a previous obstetric ultrasound (US), and then confirmed by our magnetic resonance (MR) examination. We used T2-weighted sequences, diffusion-weighted imaging sequences (DWI) and ADC maps for studying pulmonary tissue. In all cases the resulting ADC values were related to GA using Pearson correlation. RESULTS: ADC values ranged from 1,2 microm(2)/ms at 18 weeks' gestation to 3,9 microm(2)/ms at 36 weeks' gestation with a mean value, regardless for the gestational age, of 2, 352 +/- 0,623106 microm(2)/ms. We found a significant correlation between ADC and gestational age (Pearson correlation = 0,816). CONCLUSION: The ADC values correlate with gestational age since alveolar fluid secretion and angiogenesis increase gradually. Therefore, ADC can be considered as a new parameter for studying lung maturity.

MDCT of the breast.

OBJECTIVE: The purpose of this study was to evaluate retrospectively the accuracy of low-dose MDCT in the differentiation of breast lesions suspected on mammography and sonography. MATERIALS AND METHODS: MDCT was performed on 61 patients with mammographic or sonographic findings suggestive of breast cancer who could not undergo MR mammography. For each lesion, morphologic features, attenuation, and time-attenuation curve pattern were evaluated. The 1-minute cut point of attenuation was analyzed on the images. CT findings were compared with histopathologic results, which were the reference standard. RESULTS: Forty-seven of 61 patients underwent surgery, and the pathologic findings revealed 27 malignant and 20 benign lesions. With CT 25 of 27 malignant lesions and all 20 benign lesions were diagnosed correctly. CT had a sensitivity of 92.6%, specificity of 100%, positive predictive value of 100%, negative predictive value of 90.9%, and accuracy of 95.74%. The cutoff attenuation value, which had the best validity for differentiating malignant and benign lesions, was calculated to be 90 H on the 1-minute images. CONCLUSION: Our results confirm and strengthen the importance of all imaging parameters and not one in particular. Dynamic MDCT can be used in the evaluation of selected patients with suspected breast tumors.