BACKGROUND AND PURPOSE: Our aim was to determine the value of echo-planar diffusion-weighted MR imaging (epiDWI) in differentiating various types of primary parotid gland tumors.

Diffusion-weighted echo-planar MRI seems to be a valuable tool for differentiating benign from malignant primary parotid gland tumors.

Purpose: To evaluate differences in apparent diffusion coefficient (ADC) values between head, body, and tail regions and the impact of sets of b-values used in diffusion weighted imaging (DWI) of the normal pancreas. Materials and Methods:In 51 healthy volunteers echoplanar DWI of the pancreas was prospectively performed with b-values of 50, 400, and 800 s/mm 2 . All four possible combinations of b-values were used to calculate ADC values in a total of 587 regions in the pancreas head, body, and tail regions. Dependency of ADC values on the anatomical regions and on the applied sets of b-values was calculated using multivariate analysis of variance (ANOVA). Results:Mean ADC values differed significantly between the anatomical regions with the lowest values measured in the pancreatic tail (head 1.13 6 0.20, body 1.05 6 0.20, and tail 0.94 6 0.18 Â 10 À3 mm 2 /s; P < 0.05). ANOVA showed no dependency of ADC values on the sets of b-values used.Conclusion: ADC values differed significantly between the pancreatic head, body, and tail region, with decreasing ADC values toward the tail. Cautious interpretation of DWI results with adjusted, normalized values adapted to the anatomical region seems advisable. The knowledge of such differences may enhance the method's capability to differentiate between different pancreatic pathologies.

Study results confirmed the feasibility of fast breath-hold 3D GRE MR imaging of the lung.

BACKGROUND AND PURPOSE: Our aim was to compare different field strengths monitoring physiologic changes due to oral stimulation of parotid glands by using diffusion-weighted (DW) echo-planar imaging (EPI).

No abstract

No abstract

The aim of this study was to evaluate feasibility and limitations of two MR sequences for imaging of the lung using a semi-quantitative rating scale. Ten healthy volunteers were assessed with a breath-hold T1-weighted gradient-recalled-echo (TR/TE=129/2.2 ms, matrix 173 x 256) and a T2-weighted turbo spin-echo (TSE) sequence with respiratory triggering (TR/TE=3000-5000/120 ms, matrix 270 x 512) in axial 6-mm slices. The T1-weighted GRE protocol included a pre-saturation pulse over the mediastinal structures. Artefacts and resolution of vessel/airway structures in each lung segment were evaluated by two observers (10 volunteers, 180 segments). Cardiac and vessel pulsation artefacts predominated on T1-weighted GRE, respiration artefacts on T2-weighted TSE (lingula and middle lobe). Pre-saturation of the mediastinum reduced pulsation artefacts on T1-weighted GRE. T1-weighted GRE images were improved by bright flow signal of vessels, whereas image quality of T2-weighted TSE was reduced by black-blood effects in central parts of the lung. Delineation of lung periphery and the mediastinum was superior with T2-weighted TSE. Segmental/sub-segmental vessels (up to fourth/fifth order) and bronchi (up to third order) were identified. All 180 lung segments were imaged in diagnostic quality with at least one of the two sequences (T1-weighted GRE not diagnostic in 9 of 180, T2-weighted TSE in 4 of 180). Both sequences were found to be complementary: superior identification of gross lung anatomy with T1-weighted GRE and higher detail resolution in the periphery and the mediastinum with T2--weighted TSE.