Purpose: To investigate the T2 decay in prostate tissue for multiexponentiality and to assess how the biexponential model relates to established T2W contrast. Materials and Methods:A 32-echo spin-echo sequence was performed on 16 volunteers. Six single-voxel decay curves were sampled from each prostate. Prediction accuracies were assessed by jackknifing for the mono-, bi-, and triexponential models. The differences were evaluated by cross-validated analysis of variance (CVANOVA). Multiple linear regression was performed to assess the relation between parameters in the biexponential model and the contrast in T2W images.Results: Mono-, bi-, and triexponential models were preferred in 8 (10%), 72 (86%), and 4 (5%) cases, respectively. The biexponential short T2 was 64 msec (range 43 to 92 msec) and the long T2 was 490 msec (range 161 to 1319 msec). The fitted signal fraction, f, of the long T2 component was 27% (range 3% to 80%). The adjusted R 2 was 75.1% for the full regression model and decreased by 0.9%, 1.3%, and 39.2% when short T2, long T2, and f were removed from the model, respectively. Conclusion:Prostatic T2 decay was, in general, biexponential. The differences between the T2 components were large enough for accurate quantification. The T2W image contrast was primarily predicted by the biexponential signal fractions.

MRU has the potential to replace traditional diagnostic methods which use ionising radiation in paediatric patients. Further studies are needed before definite conclusions can be drawn.

Purpose: To assess image quality, vessel visualization, preliminary diagnostic properties, and interobserver variability of a novel balanced turbo field echo (b-TFE) sequence and contrast-enhanced T1 fast field echo (CE-FFE) sequence with blood pool agent (BPA). Materials and Methods:A total of 15 healthy volunteers and six patients with ultrasound-verified proximal deep vein thrombosis (DVT) were examined from the inferior vena cava (IVC) to the proximal calf veins.Results: The great majority of deep veins were completely visualized on both sequences. In healthy volunteers the IVC was completely visualized in five b-TFE and 11 CE-FFE scans, and partially in seven b-TFE and four CE-FFE scans (P ¼ 0.008). Poorest image quality was in the pelvis. Contrast-to-noise ratio (CNR) was higher on b-TFE compared to CE-FFE, with significant difference in calf images (P ¼ 0.036). Sensitivity was 100% for proximal DVT with both methods. Specificity was 70% (CE-FFE) and 80% (b-TFE) for proximal femoral DVT; 100% in distal femoral. Interobserver reliability was kappa 1.0 (b-TFE), 0.9 (CE-FFE) for proximal, and overall poor for distal DVT.Conclusion: Contrast-enhancement did not add valuable information in visualizing deep veins of the lower limbs compared to b-TFE, though the IVC was slightly better visualized. Diagnostic properties and interobserver reliability of both sequences were good for proximal DVT and poor for distal DVT.

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Purpose To assess the accuracy of magnetic resonance imaging (MRI) measurements in locally advanced oestrogen receptor-positive and human epidermal growth factor receptor 2-negative breast tumours before, during and after neoadjuvant endocrine treatment (NET) for evaluation of tumour response in comparison with clinical and pathological assessments. Methods This prospective study enrolled postmenopausal patients treated neoadjuvant with letrozole and exemestane given sequentially in an intra-patient cross-over regimen. Fifty-four patients were initially recruited, but only 35 fulfilled the inclusion criteria and confirmed to participate with a median age of 77. Tumours were scanned with MRI prior to treatment, during the eighth week of treatment and prior to surgery. Additionally, changes in longest diameter on clinical examination (CE) and tumour size at pathology were determined. Pre- and post-operative measurements of tumour size were compared in order to evaluate tumour response. Results The correlation between post-treatment MRI size and pathology was moderate and higher with a correlation coefficient (r) 0.64 compared to the correlation between CE and pathology r = 0.25. Post-treatment MRI and clinical results had a negligible bias towards underestimation of lesion size. Tumour size on MRI and CE had 0.82 cm and 0.52 cm lower mean size than tumour size measured by pathology, respectively. Conclusions The higher correlation between measurements of residual disease obtained on MRI and those obtained with pathology validates the accuracy of imaging assessment during NET. MRI was found to be more accurate for estimating complete responses than clinical assessments and warrants further investigation in larger cohorts to validate this finding.