Contrast-enhanced and unenhanced diffusion-weighted imaging of the breast at 3 T.

AIM: To evaluate the effect of intravenous gadolinium contrast agent on diffusion-weighted sequences and apparent diffusion coefficient (ADC) measurements at 3 T. MATERIALS AND METHODS: Sixty-two biopsy-proven breast lesions were included in this prospective study. Magnetic resonance imaging (MRI) was performed at 3 T, using four echo-planar diffusion-weighted sequences (7,100 ms repetition time, 84 ms echo time) with b-values of 0 and 850, and 0 and 1,000 s/mm2. The first pair of DWI sequences was taken before intravenous contrast medium injection. The second pair of sequences was taken 6.5 minutes after intravenous contrast medium administration (right after the dynamic T1 sequence). A freeform region of interest (ROI) was drawn inside the lesion excluding adjacent normal tissue, necrotic, or cystic components and ADC values were calculated. The paired samples t-test was used to assess differences between ADC measurements before and after intravenous contrast medium administration. Sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve were calculated for each diffusion sequence. RESULTS: Twenty-seven malignant and 35 benign lesions were analysed. Fifty-eight lesions were masses, and four lesions were non-mass-like enhancements (NMLEs). Two of the NMLEs were malignant, and two were benign lesions. The contrast-enhanced ADC measurements were lower than the unenhanced measurements on b=850 and 1,000 s/mm2 (p<0.05). The receiver operating characteristic (ROC) analysis displayed similar area under the curve values between the different diffusion sequences. CONCLUSION: The injection of intravenous contrast medium reduces ADC values; however, the effect of contrast medium is modest. Sensitivity and specificity are not significantly affected.

Reproducibility of apparent diffusion coefficient measurements evaluated with different workstations.

AIM: To evaluate apparent diffusion coefficient (ADC) measurements of breast lesions on different computer platforms to address post-processing influences on ADC measurement reproducibility. MATERIALS AND METHODS: One hundred biopsy-proven breast lesions were included in this prospective study. MRI examination was performed at 3 T using standard sequences and an echo planar diffusion-weighted imaging sequence with b-values of 0 and 850 s/mm2. The images were reviewed by two radiologists in consensus. Regions of interest were placed manually within the lesion, following its contour. Care was taken to exclude adjacent normal tissue or necrotic tissue and cystic components within the lesion. The mean ADC value was measured for each lesion on two different platforms: On the MRI workstation that came with the scanner and on a commercially available DICOM (digital imaging and communication in medicine) viewer. Agreement between workstation measurements was evaluated using intraclass correlation coefficient and Bland-Altman plots. RESULTS: Fifty-nine malignant and 41 benign lesions were analysed. Of the benign lesions, 28 were mass lesions and 13 were non-mass-like enhancements. In addition, 46 of the malignant lesions were masses and 13 were non-mass-like enhancements. Agreement between the two workstation measurements was high (intraclass correlation coefficients=0.981). Using Bland-Altman plots, no systematic differences were identified between workstations. Limits of agreement ranged between a minimum of -0.071×10-3 mm2/s and a maximum of 0.102×10-3 mm2/s. CONCLUSION: ADC measurements are reproducible among the workstations considered in this study.

Celiomesenteric trunk demonstrated by multi-detector computed tomography angiography: two cases of a rare vascular variation.

We present two cases of patients with celiomesenteric trunk in whom the celiac trunk and the superior mesenteric artery arise off a common vessel from the ventral part of the aorta, which was demonstrated by multi-detector (16 slices) computed tomography angiography (MDCTA) and confirmed by digital subtraction angiography (DSA). This is a very rare congenital vascular anomaly and its imaging demonstration is of great importance in several interventional procedures. These cases demonstrate the capability of MDCTA in the evaluation of abdominal aorta and its branches and shows that this method might replace diagnostic DSA.

Tele-ophthalmology and conventional ophthalmology using a mobile medical unit in remote Greece.

We evaluated the quality of medical services delivered to remote glaucoma patients from a mobile unit. A four-wheel-drive vehicle containing the necessary equipment visited five different remote locations in Greece. During a three-year prospective study, 1205 patients were examined, of whom 230 had glaucoma. The majority of the subjects were examined by the unit's medical staff using the available instrumentation (e.g. slit-lamp and tonometer), while 56 glaucoma subjects were telemedically examined by consultants at the Patissia General Hospital, in Athens. Control data were obtained from a random sample of 260 urban glaucoma patients. A significantly greater proportion of the remote patients had an inadequate awareness of glaucoma (77%) compared with the urban patients (20%). Significantly more remote patients had poorer compliance (68%) in comparison with urban patients (23%). A significantly larger proportion of the remote patients had high intra-ocular pressure (21%) compared with the urban patients (5%). Technical difficulties occurred in the 13 of the 56 telemedical examinations. Mobile medical units can enhance access to medical services and contribute to the health-care of under-served populations.