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Objective: To describe the appearances of colorectal liver metastases on diffusionweighted MRI (DW-MRI) and to compare these appearances with histopathology. Methods: 43 patients with colorectal liver metastases were evaluated using breathhold DW-MRI (b values 0, 150 and 500 s mm-2). The b=500 s mm-2 DW-MRI were reviewed consensually for lesion size and appearance by two readers. 18/43 patients underwent surgery allowing radiological-pathological comparison. Tissue sections were reviewed by a pathologist, who classified metastases histologically as cellular, fibrotic, necrotic or mixed. The frequency of DW-MRI findings and histological features were compared using the χ² test. Results: 84 metastases were found in 43 patients. On b=500 s mm-2 DW-MRI, metastases showed three high signal intensity patterns: rim (55/84), uniform (23/84) and variegate (6/84). Of the 55 metastases showing rim pattern, 54 were .1 cm in diameter (p<0.01, χ² test). 25/84 metastases were surgically resected. Of these, 11/22 metastases .1 cm in diameter showed rim pattern and demonstrated central necrosis at histopathology (p=atterns with histology. Conclusion: Rim high signal intensity was the most common appearance of colorectal liver metastases .1 cm diameter on DW-MRI at b values of 500 s mm-2, a finding attributable to central necrosis. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To determine the T 2 relaxation time of colorectal hepatic metastases and changes in T 2 relaxation times following chemotherapy. Materials and methods: 42 patients with 96 hepatic colorectal metastases underwent baseline MRI. Axial T 1, T 2 and multi-echo GRASE sequences were acquired. ROIs were drawn on T 2 relaxation maps, obtained from GRASE images, encompassing metastasis and normal liver to record T 2 relaxation time values. In 11 patients with 28 metastases, MRI was repeated using same protocol at 6 weeks following chemotherapy. The median pre-treatment T 2 values of metastases and normal liver were compared using the Mann–Whitney test. The pre- and post-treatment median T 2 values of metastases were compared using the Wilcoxon–Rank test for responding (n =16) and non-responding (n =12) lesions defined by RECIST criteria. The change in T 2 values (ΔT 2) were compared and correlated with percentage change in lesion size. Results: There was no difference in the pre-treatment median T 2 of metastases between responding (67.3±8.6) and non-responding metastases (71.4±16.5). At the end of chemotherapy, there was a decrease in the median T 2 of responding lesions (61.6±12.6) p =0.83, and increase in non-responding lesions (76.2±18.4) p =0.03, but these were not significantly different from the pre-treatment values. There was no significant difference in ΔT 2 of responding and non-responding lesions (p =0.18) and no correlation was seen between size change and ΔT 2 (coefficient=0.3). Conclusion: T 2 relaxation time does not appear to predict response of colorectal liver metastasis to chemotherapy. [Copyright &y& Elsevier]

Objective. Image quality in whole-body MRI (WB-MRI) may be degraded by faulty radiofrequency (RF) coil elements or mispositioning of the coil arrays. Phantom-based quality control (QC) is used to identify broken RF coil elements but the frequency of these acquisitions is limited by scanner and staff availability. This work aimed to develop a scan-specific QC acquisition and processing pipeline to detect broken RF coil elements, which is sufficiently rapid to be added to the clinical WB-MRI protocol. The purpose of this is to improve the quality of WB-MRI by reducing the number of patient examinations conducted with suboptimal equipment. Approach. A rapid acquisition (14 s additional acquisition time per imaging station) was developed that identifies broken RF coil elements by acquiring images from each individual coil element and using the integral body coil. This acquisition was added to one centre's clinical WB-MRI protocol for one year (892 examinations) to evaluate the effect of this scan-specific QC. To demonstrate applicability in multi-centre imaging trials, the technique was also implemented on scanners from three manufacturers. Main results . Over the course of the study RF coil elements were flagged as potentially broken on five occasions, with the faults confirmed in four of those cases. The method had a precision of 80% and a recall of 100% for detecting faulty RF coil elements. The coil array positioning measurements were consistent across scanners and have been used to define the expected variation in signal. Significance . The technique demonstrated here can identify faulty RF coil elements and positioning errors and is a practical addition to the clinical WB-MRI protocol. This approach was fully implemented on systems from two manufacturers and partially implemented on a third. It has potential to reduce the number of clinical examinations conducted with suboptimal hardware and improve image quality across multi-centre studies., (Creative Commons Attribution license.)

Background: Medical Imaging and radiotherapy (MIRT) are at the forefront of artificial intelligence applications. The exponential increase of these applications has made governance frameworks necessary to uphold safe and effective clinical adoption. There is little information about how healthcare practitioners in MIRT in the UK use AI tools, their governance and associated challenges, opportunities and priorities for the future., Methods: This cross-sectional survey was open from November to December 2022 to MIRT professionals who had knowledge or made use of AI tools, as an attempt to map out current policy and practice and to identify future needs. The survey was electronically distributed to the participants. Statistical analysis included descriptive statistics and inferential statistics on the SPSS statistical software. Content analysis was employed for the open-ended questions., Results: Among the 245 responses, the following were emphasised as central to AI adoption: governance frameworks, practitioner training, leadership, and teamwork within the AI ecosystem. Prior training was strongly correlated with increased knowledge about AI tools and frameworks. However, knowledge of related frameworks remained low, with different professionals showing different affinity to certain frameworks related to their respective roles. Common challenges and opportunities of AI adoption were also highlighted, with recommendations for future practice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: The Myeloma Response Assessment and Diagnosis System (MY-RADS) guidelines establish a standardised acquisition and analysis pipeline for whole-body MRI (WB-MRI) in patients with myeloma. This is the first study to assess image quality in a multi-centre prospective trial using MY-RADS., Methods: The cohort consisted of 121 examinations acquired across ten sites with a range of prior WB-MRI experience, three scanner manufacturers and two field strengths. Image quality was evaluated qualitatively by a radiologist and quantitatively using a semi-automated pipeline to quantify common artefacts and image quality issues. The intra- and inter-rater repeatability of qualitative and quantitative scoring was also assessed., Results: Qualitative radiological scoring found that the image quality was generally good, with 94% of examinations rated as good or excellent and only one examination rated as non-diagnostic. There was a significant correlation between radiological and quantitative scoring for most measures, and intra- and inter-rater repeatability were generally good. When the quality of an overall examination was low, this was often due to low quality diffusion-weighted imaging (DWI), where signal to noise ratio (SNR), anterior thoracic signal loss and brain geometric distortion were found as significant predictors of examination quality., Conclusions: It is possible to successfully deliver a multi-centre WB-MRI study using the MY-RADS protocol involving scanners with a range of manufacturers, models and field strengths. Quantitative measures of image quality were developed and shown to be significantly correlated with radiological assessment. The SNR of DW images was identified as a significant factor affecting overall examination quality., Trial Registration: ClinicalTrials.gov, NCT03188172 , Registered on 15 June 2017., Critical Relevance Statement: Good overall image quality, assessed both qualitatively and quantitatively, can be achieved in a multi-centre whole-body MRI study using the MY-RADS guidelines., Key Points: • A prospective multi-centre WB-MRI study using MY-RADS can be successfully delivered. • Quantitative image quality metrics were developed and correlated with radiological assessment. • SNR in DWI was identified as a significant predictor of quality, allowing for rapid quality adjustment., (© 2023. European Society of Radiology (ESR).)

Objectives: To investigate whether MRI-based measurements of fibro-glandular tissue volume, breast density (MRBD), and background parenchymal enhancement (BPE) could be used to stratify two cohorts of healthy women: BRCA carriers and women at population risk of breast cancer., Methods: Pre-menopausal women aged 40-50 years old were scanned at 3 T, employing a standard breast protocol including a DCE-MRI (35 and 30 participants in high- and low-risk groups, respectively). The dynamic range of the DCE protocol was characterised and both breasts were masked and segmented with minimal user input to produce measurements of fibro-glandular tissue volume, MRBD, and voxelwise BPE. Statistical tests were performed to determine inter- and intra-user repeatability, evaluate the symmetry between metrics derived from left and right breasts, and investigate MRBD and BPE differences between the high- and low-risk cohorts., Results: Intra- and inter-user reproducibility in estimates of fibro-glandular tissue volume, MRBD, and median BPE estimations were good, with coefficients of variation < 15%. Coefficients of variation between left and right breasts were also low (< 25%). There were no significant correlations between fibro-glandular tissue volume, MRBD, and BPE for either risk group. However, the high-risk group had higher BPE kurtosis, although linear regression analysis did not reveal significant associations between BPE kurtosis and breast cancer risk., Conclusions: This study found no significant differences or correlations in fibro-glandular tissue volume, MRBD, or BPE metrics between the two groups of women with different levels of breast cancer risk. However, the results support further investigation into the heterogeneity of parenchymal enhancement., Key Points: • A semi-automated method enabled quantitative measurements of fibro-glandular tissue volume, breast density, and background parenchymal enhancement with minimal user intervention. • Background parenchymal enhancement was quantified over the entire parenchyma, segmented in pre-contrast images, thus avoiding region selection. • No significant differences and correlations in fibro-glandular tissue volume, breast density, and breast background parenchymal enhancement were found between two cohorts of women at high and low levels of breast cancer risk., (© 2023. The Author(s).)

Objective: This study aims to determine local treatment response and long-term survival outcomes in patients with localised muscle-invasive bladder cancer (MIBC) patients receiving neoadjuvant chemotherapy (NAC) using diffusion-weighted MRI (DWI) and apparent diffusion coefficient (ADC) analysis., Methods: Patients with T2-T4aN0-3M0 bladder cancer suitable for NAC were recruited prospectively. DWI was performed prior to NAC and was repeated following NAC completion. Conventional response assessment was performed with cystoscopy and tumour site biopsy. Response was dichotomised into response (all ) and high b-values (ADC b100 ). Mean ADC, percentiles, skew, kurtosis, and their change (ΔADC and %ΔADC) were determined. Threshold predictive of response with highest specificity was ascertained using receiver operating characteristic (ROC) analysis. Median overall survival (OS), bladder-cancer-specific survival (bCSS), progression-free survival (PFS), and time to cystectomy were estimated using Kaplan-Meier method. Significant area under the curve (AUC) cut points were used to determine relationship with long-term endpoints and were compared using log-rank test., Results: Forty-eight patients (96 DWI) were evaluated. NAC response was associated with significant increase in mean ΔADC and %ΔADC compared to poor response (ΔADC all 0.32×10 -3 versus 0.11×10 -3 mm 2 /s; p=0.009, and %ΔADC all 21.70% versus 8.23%; p=0.013). Highest specificity predicting response was seen at 75th percentile ADC (AUC, 0.8; p=0.01). Sensitivity, specificity, positive predictive power, and negative predictive power of %ΔADC b100 75th percentile was 73.7%, 90.0%, 96.6%, and 52.9%, respectively. %ΔADC b100 75th percentile >15.5% was associated with significant improvement in OS (HR, 0.40; 95% CI, 0.19-0.86; p=0.0179), bCSS (HR, 0.26; 95% CI, 0.08-0.82; p=0.0214), PFS (HR, 0.16; 95% CI, 0.05-0.48; p=0.0012), and time to cystectomy (HR, 0.19; 95% CI, 0.07-0.47; p=0.0004)., Conclusions: Quantitative ADC analysis can successfully identify NAC response and improved long-term clinical outcomes. Multi-centre validation to assess reproducibility and repeatability is required before testing within clinical trials to inform MIBC treatment decision making., Advances in Knowledge: We successfully demonstrated that measured change in DWI can successfully identify NAC response and improved long-term survival outcomes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hafeez, Koh, Jones, Ghzal, D’Arcy, Kumar, Khoo, Lalondrelle, McDonald, Thompson, Scurr, Sohaib and Huddart.)

Background: Whole-body (WB) MRI, which includes diffusion-weighted imaging (DWI) and T 1 -w Dixon, permits sensitive detection of marrow disease in addition to qualitative and quantitative measurements of disease and response to treatment of bone marrow. We report on the first study to embed standardised WB-MRI within a prospective, multi-centre myeloma clinical trial (IMAGIMM trial, sub-study of OPTIMUM/MUKnine) to explore the use of WB-MRI to detect minimal residual disease after treatment., Methods: The standardised MY-RADS WB-MRI protocol was set up on a local 1.5 T scanner. An imaging manual describing the MR protocol, quality assurance/control procedures and data transfer was produced and provided to sites. For non-identical scanners (different vendor or magnet strength), site visits from our physics team were organised to support protocol optimisation. The site qualification process included review of phantom and volunteer data acquired at each site and a teleconference to brief the multidisciplinary team. Image quality of initial patients at each site was assessed., Results: WB-MRI was successfully set up at 12 UK sites involving 3 vendor systems and two field strengths. Four main protocols (1.5 T Siemens, 3 T Siemens, 1.5 T Philips and 3 T GE scanners) were generated. Scanner limitations (hardware and software) and scanning time constraint required protocol modifications for 4 sites. Nevertheless, shared methodology and imaging protocols enabled other centres to obtain images suitable for qualitative and quantitative analysis., Conclusions: Standardised WB-MRI protocols can be implemented and supported in prospective multi-centre clinical trials. Trial registration NCT03188172 clinicaltrials.gov; registration date 15th June 2017 https://clinicaltrials.gov/ct2/show/study/NCT03188172., (© 2022. The Author(s).)

Objective: To present and evaluate an automated method to correct scaling between Dixon water/fat images used in breast density (BD) assessments., Methods: Dixon images were acquired in 14 subjects with different T 1 weightings (flip angles, FA, 4°/16°). Our method corrects intensity differences between water ( W ) and fat ( F ) images via the application of a uniform scaling factor (SF), determined subject-by-subject. Based on the postulation that optimal SFs yield relatively featureless summed fat/scaled-water ( F + W S F ) images, each SF was chosen as that which generated the lowest 95th-percentile in the absolute spatial-gradient image-volume of F + W S F . Water-fraction maps were calculated for data acquired with low/high FAs, and BD (%) was the total percentage water within each breast volume., Results: Corrected/uncorrected BD ranged from, respectively, 10.9-71.8%/8.9-66.7% for low-FA data to 8.1-74.3%/5.6-54.3% for high-FA data. Corrected metrics had an average absolute increase in BD of 6.4% for low-FA data and 18.4% for high-FA data. BD values estimated from low- and high-FA data were closer following SF-correction., Conclusion: Our results demonstrate need for scaling in such BD assessments, where our method brought high-FA and low-FA data into closer agreement., Advances in Knowledge: We demonstrated a feasible method to address a main source of inaccuracy in Dixon-based BD measurements.

CT-based radiotherapy workflow is limited by poor soft tissue definition in the pelvis and reliance on rigid registration methods. Current image-guided radiotherapy and adaptive radiotherapy models therefore have limited ability to improve clinical outcomes. The advent of MRI-guided radiotherapy solutions provides the opportunity to overcome these limitations with the potential to deliver online real-time MRI-based plan adaptation on a daily basis, a true "plan of the day." This review describes the application of MRI guided radiotherapy in two pelvic tumour sites likely to benefit from this approach.

Purpose: To propose a method to quantify T 1 and contrast agent uptake in breast dynamic contrast-enhanced (DCE) examinations undertaken with standard clinical fat-suppressed MRI sequences and to demonstrate the proposed approach by comparing the enhancement characteristics of lobular and ductal carcinomas., Methods: A standard fat-suppressed DCE of the breast was performed at 1.5 T (Siemens Aera), followed by the acquisition of a proton density (PD)-weighted sequence, also fat suppressed. Both sequences were characterized with test objects (T 1 ranging from 30 ms to 2,400 ms) and calibration curves were obtained to enable T 1 calculation. The reproducibility and accuracy of the calibration curves were also investigated. Healthy volunteers and patients were scanned with Ethics Committee approval. The effect of B 0 field inhomogeneity was assessed in test objects and healthy volunteers. The T 1 of breast tumors was calculated at different time points (pre-, peak-, and post-contrast agent administration) for 20 patients, pre-treatment (10 lobular and 10 ductal carcinomas) and the two cancer types were compared (Wilcoxon rank-sum test)., Results: The calibration curves proved to be highly reproducible (coefficient of variation under 10%). T 1 measurements were affected by B 0 field inhomogeneity, but frequency shifts below 50 Hz introduced only 3% change to fat-suppressed T 1 measurements of breast parenchyma in volunteers. The values of T 1 measured pre-, peak-, and post-contrast agent administration demonstrated that the dynamic range of the DCE sequence was correct, that is, image intensity is approximately directly proportional to 1/T 1 for that range. Significant differences were identified in the width of the distributions of the post-contrast T 1 values between lobular and ductal carcinomas (P < 0.05); lobular carcinomas demonstrated a wider range of post-contrast T 1 values, potentially related to their infiltrative growth pattern., Conclusions: This work has demonstrated the feasibility of fat-suppressed T 1 measurements as a tool for clinical studies. The proposed quantitative approach is practical, enabled the detection of differences between lobular and invasive ductal carcinomas, and further enables the optimization of DCE protocols by tailoring the dynamic range of the sequence to the values of T 1 measured., (© 2017 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.)

An Active Breathing Coordinator (ABC) can be employed to induce breath-holds during CT imaging and radiotherapy of lung, breast and liver cancer, and recently during lung cancer MRI. The apparatus measures and controls respiratory volume, hence subject lung volume reproducibility is its principal measure of effectiveness. To assess ABC control quality, the intra-session reproducibility of ABC-induced lung volumes was evaluated and compared with that reached by applying the clinical standard of operator-guided self-sustained breath-holds on healthy volunteers during MRI. Inter-session reproducibility was investigated by repeating ABC-controlled breath-holds on a second visit. Additionally, lung volume agreement with ABC devices used with different imaging modalities in the same institution (MR, CT), or for a breast trial treatment, was assessed. Lung volumes were derived from three-dimensional (3D) T1-weighted MRI datasets by three observers employing semiautomatic lung delineation on a radiotherapy treatment planning system. Inter-observer variability was less than 6% of the delineated lung volumes. Lung volume agreement between the different conditions over all subjects was investigated using descriptive statistics. The ABC equipment dedicated for MR application exhibited good intra-session and inter-session lung volume reproducibility (1.8% and 3% lung volume variability on average, respectively). MR-assessed lung volumes were similar using different ABC equipment dedicated to MR, CT, or breast radiotherapy. Overall, lung volumes controlled by the same or different ABC devices agreed better than with self-controlled breath-holds, as suggested by the average ABC variation of 1.8% of the measured lung volumes (99 mL), compared to the 4.1% (226 mL) variability observed on average with self-sustained breath-holding., (© 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.)

MRI has been extensively used in breast cancer staging, management and high risk screening. Detection sensitivity is paramount in breast screening, but variations of signal-to-noise ratio (SNR) as a function of position are often overlooked. We propose and demonstrate practical methods to assess spatial SNR variations in dynamic contrast-enhanced (DCE) breast examinations and apply those methods to different protocols and systems. Four different protocols in three different MRI systems (1.5 and 3.0 T) with receiver coils of different design were employed on oil-filled test objects with and without uniformity filters. Twenty 3D datasets were acquired with each protocol; each dataset was acquired in under 60 s, thus complying with current breast DCE guidelines. In addition to the standard SNR calculated on a pixel-by-pixel basis, we propose other regional indices considering the mean and standard deviation of the signal over a small sub-region centred on each pixel. These regional indices include effects of the spatial variation of coil sensitivity and other structured artefacts. The proposed regional SNR indices demonstrate spatial variations in SNR as well as the presence of artefacts and sensitivity variations, which are otherwise difficult to quantify and might be overlooked in a clinical setting. Spatial variations in SNR depend on protocol choice and hardware characteristics. The use of uniformity filters was shown to lead to a rise of SNR values, altering the noise distribution. Correlation between noise in adjacent pixels was associated with data truncation along the phase encoding direction. Methods to characterise spatial SNR variations using regional information were demonstrated, with implications for quality assurance in breast screening and multi-centre trials.

A commercial active breathing coordinator (ABC) device, employed to hold respiration at a specific level for a predefined duration, was successfully adapted for magnetic resonance imaging (MRI) use for the first time. Potential effects of the necessary modifications were assessed and taken into account. Automatic MR acquisition during ABC breath holding was achieved. The feasibility of MR-ABC thoracic and abdominal examinations together with the advantages of imaging in repeated ABC-controlled breath holds were demonstrated on healthy volunteers. Five lung cancer patients were imaged under MR-ABC, visually confirming the very good intra-session reproducibility of organ position in images acquired with the same patient positioning as used for computed tomography (CT). Using identical ABC settings, good MR-CT inter-modality registration was achieved. This demonstrates the value of ABC, since application of T1, T2 and diffusion weighted MR sequences provides a wider range of contrast mechanisms and additional diagnostic information compared to CT, thus improving radiotherapy treatment planning and assessment.

Purpose: To document the apparent diffusion coefficient (ADC) of fibroglandular breast tissue in women at high-risk of developing breast cancer and investigate the relationship between ADC and breast density., Materials and Methods: Local research ethics approval was obtained. A total of 33 high-risk women including 17 BRCA1/2 mutation carriers (mean age, 43 years) and 16 women postmantle irradiation (mean age 40 years) underwent diffusion-weighted MRI between days 6 and 16 of their menstrual cycle. ADC histograms from a region of interest in fibroglandular tissue and mammographic breast density measurements were obtained. Mean, percentile ADC values (10th, 25th, 50th, 75th, 90th) and skew were compared for the two groups; ADC and mammographic breast density were correlated., Results: Mean ADC values (×10(-6) mm(2) /s) were 2017 ± 197 in postmantle irradiated women and 1827 ± 289 in BRCA1/2 mutation carriers (P = 0.035) with significant differences at all percentiles (P < 0.0001) but not skew (P = 0.44). ADC values showed weak positive correlation with mammographic breast density in BRCA1/2 mutation carriers (r = 0.51, P = 0.043) but not in postmantle radiotherapy patients (r = 0.49, P = 0.13)., Conclusion: Higher ADC values seen in fibroglandular tissue postmantle irradiation compared with BRCA1/2 mutation carriers has potential to improve tumor detection in these patients. Lack of correlation between ADC and breast density postmantle irradiation may be a result of microstructural changes., (Copyright © 2013 Wiley Periodicals, Inc.)

Aim: To assess the feasibility of using cine-MR to study intra-fractional time-volume and volume-deformity patterns of the bladder during radiotherapy as initial methodology for Predictive Organ Localization (POLO)., Methods: Nine patients receiving radiotherapy for localized muscle invasive bladder cancer were prospectively studied. Each had an MR scan performed on an empty bladder using a T1 weighted cine sequence over a period of 20 min. Scans were taken prior to, and repeated towards the end of, radiotherapy treatment. Time-volume sequences were determined and compared before and during radiotherapy. Absolute bladder volumes were then correlated with changes in bladder wall position., Results: The mean post void residual bladder volume prior to radiotherapy at time 0 was 113 cm(3) [SD 53] and this did not differ significantly during radiotherapy -106 cm [SD 40] (p=0.24, paired t-test analysis). A linear relationship was observed for the rate bladder filling over a 20 min period, which did not significantly change on the cine-MR during radiotherapy (regression coefficient 2.1 vs 1.6, respectively, p=0.51). Significant positive relationships were seen between volume and anterior (p=0.02), superior (p<0.001), and inferior (p=0.03) wall motion. These relationships were complex, though linearity was observed for volumes up to 150 cm(3). The 1.5 cm CTV-PTV margin was sufficient to account for expansion in the majority of cases with the only breach occurring on the anterior wall in one patient., Conclusions: This study confirms the feasibility of using cine-MR for POLO. The development of such predictive methodology may compensate for the need to use an isotropic CTV-PTV margin to simply cover bladder filling when using image-guided radiotherapy.

Objective: The purposes of this study were to determine whether the pretreatment apparent diffusion coefficients (ADCs) of hepatic metastatic lesions from colorectal cancer are predictive of response to chemotherapy and to compare the ADCs of metastatic lesions before and after chemotherapy., Subjects and Methods: Twenty patients with potentially operable hepatic lesions larger than 1 cm in diameter metastatic from colorectal carcinoma were prospectively evaluated with diffusion-weighted imaging at three b values before and after chemotherapy. Quantitative ADC maps were calculated with images with b values of 0, 150, and 500 s/mm2 (ADC0-500) and with images with b values of 150 and 500 s/mm2 (ADC150-500). Regions of interest were drawn around metastatic lesions and randomly over liver. The mean ADC0-500 and mean ADC150-500 of metastatic lesions before and after chemotherapy were compared according to response defined by Response Evaluation Criteria in Solid Tumors criteria., Results: Twenty-five responding and 15 nonresponding metastatic lesions were evaluated. Nonresponding lesions had a significantly higher pretreatment mean ADC0-500 and mean ADC150-500 than did responding lesions (Mann-Whitney U test, p < 0.002). There was a linear regression relation (r2 = 0.34, p = 0.02) between percentage size reduction of metastatic lesions and pretreatment mean ADC150-500. After chemotherapy, responding lesions had a significant increase in mean ADC0-500 and ADC150-500 (Wilcoxon's signed rank, p = 0.025). No significant change was observed in nonresponding metastatic lesions (Wilcoxon's signed rank, p > 0.5) or in normal liver parenchyma (Wilcoxon's signed rank, p > 0.4)., Conclusion: High pretreatment mean ADC0-500 and mean ADC150-500 of colorectal hepatic metastatic lesions were predictive of poor response to chemotherapy. A significant increase in mean ADC0-500 and ADC150-500 was observed in metastatic lesions that responded to chemotherapy. These findings may have implications for development of individualized therapy.

The aim of this work was to determine the potential of diffusion weighted magnetic resonance imaging (DW-MRI) for identifying prostate cancer by comparing apparent diffusion coefficients (ADCs) from malignant peripheral zone (PZ) nodules with values from the non-malignant PZ and the predominantly benign central gland (CG). 33 patients with elevated prostate specific antigen (PSA) aged 52-78 years (30 patients with biopsy proven prostate cancer) underwent endorectal MRI with T2 weighted and echo planar diffusion weighting (b = 0 mm2 s(-1), 300 mm2 s(-1), 500 mm2 s(-1) and 800 mm2 s(-1)) sequences. ADCs were measured from 30 malignant PZ nodules (identified on T2 weigting and positive biopsy; median region of interest (ROI) size 41 mm2), 33 CG regions (predominantly benign nodules; median ROI size 218 mm2) and 18 non-malignant PZ regions (ipsilateral biopsies all benign; median ROI size 54.5 mm2). ADCs were (mean+/-standard deviation (SD); mm2 s(-1)): malignant PZ nodules 1.30+/-0.30x10(-3), CG 1.46+/-0.14x10(-3) and non-malignant PZ 1.71+/-0.16x10(-3). Differences between all three groups were statistically significant (p = 0.01 malignant PZ vs CG; p = 0.0001 malignant PZ vs non-malignant PZ and p = 0.0001 CG vs non-malignant PZ). Using receiver operating characteristic curves, cut-off values of 1.39x10(-3) mm2 s(-1) differentiated malignant PZ nodules from predominantly benign CG (sensitivity 60%, specificity 76%) and of 1.6x10(-3) mm2 s(-1) identified malignant from non-malignant PZ (sensitivity 86.7%, specificity 72.2%). These results suggest that DW-MRI has the potential to increase the specificity of prostate cancer detection because ADCs are significantly lower in malignant compared with non-malignant prostate tissue.

This paper describes the development and optimization of an innovative technique using an external surface coil to obtain high resolution, thin section MR images of the oesophagus using volunteers. T2 weighted fast spin echo sequences were performed with and without cardiac gating. The field of view (FOV), matrix size, slice thickness, number of signal averages (NSA), and repetition time (TR)/echo time (TE) were altered to optimize signal to noise ratio (SNR) whilst maintaining spatial resolution. The effect of cardiac gating was also investigated. Workstation images were evaluated on the ability to visualize: individual oesophageal wall layers; perioesophageal fat; the azygos vein and wall of the descending aorta, giving qualitative assessment of image clarity. The optimum sequence enabled the layers of the oesophageal wall and perioesophageal tissues to be demonstrated in an acceptable scan time of 7.07 min. A FOV of less than 250 mm degraded image quality so that individual oesophageal wall layers could not be depicted and noise within the image impaired visualization of posterior mediastinal structures. The results indicate that high resolution imaging of the oesophagus using an external surface coil can depict anatomic structures clearly and that the use of cardiac gating improves image clarity. The technique offers an alternative, non-invasive method of detailed imaging of the oesophagus.

Mangafodipir trisodium (MnDPDP) is a contrast agent for use in magnetic resonance imaging (MRI) of the liver. The agent is taken up by normal hepatocytes resulting in increased signal on T1-weighted imaging, and is excreted in the biliary system. Hepatocyte-containing liver neoplasms such as hepatomas or focal nodular hyperplasia (FNH), take up MnDPDP and demonstrate varying degrees of enhancement. Metastatic liver deposits and primary liver tumours of non-hepatocyte origin do not typically enhance with MnDPDP thus increasing their conspicuity compared with pre-contrast T1-weighted images. Metastases may demonstrate rim enhancement particularly on delayed imaging at 24 h, which can increase their conspicuity, thus allowing better visualization of small lesions. Functional biliary obstruction due to liver metastases can also result in wedge shaped areas of parenchymal enhancement. The MRI features of various focal liver after continuance with lesions following MnDPDP are discussed and illustrated including primary lesions such as hepatoma and secondary metastases.

Magnetic resonance (MR) imaging and MR cholangiopancreatography are useful, noninvasive techniques for the assessment of pancreatic and hepatobiliary complications in cystic fibrosis. Abnormalities of the pancreas in cystic fibrosis are typically characterized by fat deposition, which has increased signal intensity on T1-weighted MR images, and pancreatic fibrosis, which has low signal intensity on both T1- and T2-weighted images. Pancreatic cysts are a relatively common finding; these cysts are typically quite small but are well demonstrated at MR imaging and MR cholangiopancreatography. Pancreatic duct abnormalities are also occasionally seen. Hepatic manifestations range from hepatomegaly and diffuse fatty infiltration to severe cirrhosis with fibrotic change, regenerative nodules, and portal hypertension. Splenomegaly is often characterized by siderotic nodules that manifest as multiple focal areas of abnormal low signal intensity within the spleen. Biliary manifestations include cholelithiasis, stricturization, and narrowing or dilatation of intra- and extrahepatic bile ducts. Gallbladder abnormalities including microgallbladder are also readily demonstrated. MR cholangiopancreatography can be used to help determine the presence and severity of biliary complications without resorting to more invasive procedures and, in conjunction with MR imaging, may prove useful in the assessment of patients with cystic fibrosis who present with abdominal symptoms that suggest hepatobiliary involvement.