• MABp1 as a novel antibody treatment for advanced colorectal cancer: a randomised, double-blind, placebo-controlled, phase 3 study.

      Hickish, T; Andre, T; Wyrwicz, L; Saunders, Mark P; Sarosiek, T; Kocsis, J; Nemecek, R; Rogowski, W; Lesniewski-Kmak, K; Petruzelka, L; et al. (2017-02)
      MABp1, an antibody that targets interleukin 1α, has been associated with antitumour activity and relief of debilitating symptoms in patients with advanced colorectal cancer. We sought to establish the effect of MABp1 with a new primary endpoint in patients with advanced colorectal cancer.
    • Machine learning and radiomics applications in esophageal cancers using non-invasive imaging methods—a critical review of literature.

      Xie, C-Y; Pang, Chun-Lap; Chan, B; Yuen-yuen Wong, E; Du, Q; Vardanabhuti, V; Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China. (2021)
      Esophageal cancer (EC) is of public health significance as one of the leading causes of cancer death worldwide. Accurate staging, treatment planning and prognostication in EC patients are of vital importance. Recent advances in machine learning (ML) techniques demonstrate their potential to provide novel quantitative imaging markers in medical imaging. Radiomics approaches that could quantify medical images into high-dimensional data have been shown to improve the imaging-based classification system in characterizing the heterogeneity of primary tumors and lymph nodes in EC patients. In this review, we aim to provide a comprehensive summary of the evidence of the most recent developments in ML application in imaging pertinent to EC patient care. According to the published results, ML models evaluating treatment response and lymph node metastasis achieve reliable predictions, ranging from acceptable to outstanding in their validation groups. Patients stratified by ML models in different risk groups have a significant or borderline significant difference in survival outcomes. Prospective large multi-center studies are suggested to improve the generalizability of ML techniques with standardized imaging protocols and harmonization between different centers.
    • Machine QA for the Elekta Unity system: a report from the Elekta MR-Linac consortium

      Roberts, D. A.; Sandin, C.; Vesanen, P. T.; Lee, H.; Hanson, I. M.; Nill, S.; Perik, T.; Lim, S. B.; Vedam, S.; Yang, J.; et al. (2021)
      Over the last few years magnetic resonance image guided radiotherapy systems have been introduced into the clinic, allowing for daily online plan adaption. While quality assurance (QA) is similar to conventional radiotherapy systems, there is a need to introduce or modify measurement techniques. As yet, there is no consensus guidance on the QA equipment and test requirements for such systems. Therefore, this report provides an overview of QA equipment and techniques for mechanical, dosimetric, and imaging performance of such systems and recommendation of the QA procedures, particularly for a 1.5 T MR-Linac device. An overview of the system design and considerations for QA measurements, particularly the effect of the machine geometry and magnetic field on the radiation beam measurements is given. The effect of the magnetic field on measurement equipment and methods is reviewed to provide a foundation for interpreting measurement results and devising appropriate methods. And lastly, a consensus overview of recommended QA, appropriate methods and tolerances is provided based on conventional QA protocols. The aim of this consensus work is to provide a foundation for QA protocols, comparative studies of system performance, and for future development of QA protocols and measurement methods.
    • Macroglobulinaemia and intestinal lymphangiectasia: a rare association.

      Harris, Martin; Burton, I E; Scarffe, J Howard; Department of Histopathology, Christie Hospital and Holt Radium Institute, Manchester (1983-01)
      Two cases in which macroglobulinaemia was associated with intestinal lymphangiectasia are recorded. Immunoperoxidase stains demonstrated a high content of monoclonal IgM in the intestinal lymph. The seven previously recorded examples of this association are reviewed. It is concluded that the concurrence of these two conditions is not merely fortuitous, and that increased viscosity of the lymph consequent on its high IgM content may be important in the pathogenesis of the intestinal lymphangiectasia.
    • A macropencil beam model: clinical implementation for conformal and intensity modulated radiation therapy.

      Phillips, Mark H; Singer, Karen M; Hounsell, Alan R; Department of Radiation Oncology, University of Washington Medical Center, Seattle 98195-6043, USA. (1999-04)
      The increasing use of irregularly shaped, off-centre fields in advanced treatment techniques, particularly intensity modulated radiation therapy, has strained the limits of conventional, broad-beam dose calculation algorithms. More recent models, such as kernel-based pencil beams and Monte Carlo methods, are accurate but suffer from the time needed for calculations and from the lack of clearly established methods for determining the parameters needed to match calculations with the particular dosimetric characteristics of an individual machine. This paper presents the implementation of a model that uses an extended source model to calculate the variation of fluence at the patient surface for any arbitrarily shaped field. It uses a macropencil beam model to calculate phantom scatter. Both head scatter and phantom scatter models use exponential functions fit to a series of measurements to determine the model's parameters. The means by which the model can be implemented in a clinical setting using standard dosimetric equipment is presented. Results for two separate machines and three energies are presented. Comparisons with measurements for a set of regular and irregular fields demonstrate the accuracy of the model for conventional, conformal and intensity modulated treatments. For rectangular and irregular fields at depths up to 20 cm, the accuracy was better than < or =1.5%, compared with errors of up to 7.5% with a standard algorithm. For a 20-step intensity modulated field, the accuracy was 3.4% compared with 18% with the conventional algorithm. The advantages of this model for IMRT are discussed.
    • Macrophage inflammatory protein 1alpha attenuates the toxic effects of temozolomide in human bone marrow granulocyte-macrophage colony-forming cells.

      Clemons, Mark; Watson, Amanda J; Howell, Anthony; Chang, James; Heyworth, Clare M; Lord, Brian I; Testa, Nydia G; Dexter, T Michael; Margison, Geoffrey P; Cancer Research Campaign Department of Medical Oncology, Manchester, United Kingdom. markclemons@sprint.ca (2000-03)
      Macrophage inflammatory protein 1alpha (MIP-1alpha) is a chemokine that may act principally by preventing hemopoietic cells from entering G1, thereby attenuating the cytotoxic effects of cell cycle-specific chemotherapeutic agents. Here we examine the effect of MIP-1alpha on the sensitivity of human granulocyte-macrophage hemopoietic progenitor cells (granulocyte-macrophage colony-forming cells; GM-CFCs) with the cytotoxic effects of antitumor agents that act mainly via alkylation at the O6 position of guanine in DNA. Mononuclear cell preparations from human bone marrow were used in an in vitro GM-CFC colony-forming assay. The GM-CFC survival from individual patients displayed a range of sensitivities to the methylating agent temozolomide [(Tz) 20-55% survival at 10 microg/ml Tz]. However, in all 16 cases, MIP-1alpha (50 ng/ml) protected against GM-CFC killing: survival in the presence of MIP-1alpha ranged from 65-97% at 10 microg/ml Tz, with GM-CFCs being 1.5-4.5-fold more resistant than control cells from the same patient. The highest levels of protection were seen in the GM-CFCs with the highest sensitivity in the absence of MIP-1alpha. Similar degrees of protection were seen for the methylating agent streptozotocin, but no protection was detected for the chloroethylating agents carmustine or mitozolomide in the samples for which there was protection against the toxic effects of Tz. Whereas the mechanism of this effect remains to be established, the results may have potential immediate clinical application in the attenuation of hematological toxicity after administration of methylating antitumor agents.
    • Macular translocation surgery: computer simulation of visual perception.

      Wong, D; Liazos, S; Mehta, J; Farnell, Damian J J; St. Paul's Eye Unit, Royal Liverpool University Hospital Trust, Liverpool L7 8XP, UK. (2008-06)
      BACKGROUND: Macular translocation can be associated with visual improvement, but patients often experience symptoms of confusion or diplopia. There is a high incidence of suppression of the operated or the fellow eye. The aim of this study is to use computer software to examine the pre- and post-operative fundal images, in order to better understand how patients see after macular translocation surgery. METHODS: We created a graphical user interface that allowed a user to identify and record common landmark points in pre- and post-operative fundal images. We used these points to carry out interpolations using two algorithms, namely bilinear and thin-plate spline transformations. The transformations were applied to the Mona Lisa in order to appreciate how patients might see. RESULTS: Given two sets of corresponding points, both algorithms were able to approximate the effect of the surgery. Bilinear transformation was able to account for changes to the retina as a whole, including rotation, stretches, compression and shear. The thin-plate spline algorithm additionally accounted for the considerable regional and uneven local effects. Applying the later algorithm to the Mona Lisa produced inconsistent and warped images. CONCLUSIONS: Our results confirmed that neurosensory redistribution was associated with most cases of MT360. We infer from these results that corresponding retinal elements between two eyes would no longer correspond after surgery. The distortion of images from the operated eye could not be completely corrected by squint surgery, and this may account for the high incidence of suppression of the fellow or the operated eye after surgery.
    • Made to measure survey.

      Eardley, Anne; Lancaster, Gillian; Elkind, Andrea; Christie Hospital and Holt Radium Institute, Manchester. (1990-11-29)
    • Magnetic order in a spin-half interpolating square-triangle Heisenberg antiferromagnet

      Bishop, R F; Li, P H Y; Farnell, Damian J J; Campbell, C E; School of Physics and Astronomy, Schuster Building, The University of Manchester, Manchester, M13 9PL, UK (2009)
    • Magnetic resonance appearance of normal inguinal nodes.

      Grey, Alistair C; Carrington, Bernadette M; Hulse, Paul; Swindell, Ric; Yates, W; Department of Diagnostic Radiology, Christie Hospital NHS Trust, Wilmslow Road, Withington, Manchester, M20 4BX, U.K. (2000-02)
      AIM: To identify adult inguinal lymph node anatomical subgroups using magnetic resonance imaging (MRI), to derive a normal range for nodal number and size and to describe their morphology. MATERIALS AND METHODS: Eighty-three oncology patients with low stage pelvic tumours had inguinal lymph node assessment by MRI. Nodes were divided into proximal superficial (PS), distal superficial (DS) and deep inguinal (DI) subgroups, their number counted in two planes, and their transaxial short axis diameter recorded. Consistency of the largest node was recorded for each anatomical subgroup and two vertical distances measured, between the skin surface and the ipsilateral pubis, and between the skin surface and the deepest node. RESULTS: Transaxial plane maximum nodal number at the three sites was: PS 5, DS 8, DI 3; and in the coronal plane: PS 7, DS 5, DI 3. Nodal size ranges were: PS 3-10 mm (mean 4 mm), DS 3-15 mm (mean 6 mm) and DI3-10 mm (mean 6 mm). There was no correlation between nodal size or number and age or gender. Nodes were usually uniformly solid (PS 44%; DS 37%, DI 45%), or fatty (PS 39%; DS 33%; DI 25%). The range of distances between the skin and deepest lymph node was 2.5-16 cm depending on patient fatness. CONCLUSION: The mean number of nodes counted in the axial plane was six and in the coronal plane five. A maximum short axis diameter of 15 mm was recorded for inguinal lymph nodes.
    • Magnetic resonance guided adaptive Radiotherapy (MRgRT) for localised prostate cancer: The first result from a prospective international registry for the evidence-based Introduction of MRgRT

      Teunissen, F. R.; Willigenburg, T.; Tree, A. C.; Hall, W. A.; Choi, S. L.; Choudhury, Ananya; Christodouleas, J. P.; De Boer, J. C. J.; De Groot-Van Breugel, E. N.; Kerkmeijer, L. G. W.; et al. (2021)
      Introduction & Objectives: Magnetic Resonance (MR) guided adaptive radiotherapy (MRgRT) is a new technique for treatment of localised Prostate Cancer (PCa). MR-guided linear accelerator (MR-Linac) systems have been implemented in radiotherapy departments around the world. However, the theoretical benefits of MRgRT still need to be confirmed in clinical practice. We report the short-term outcomes for the first PCa patients treated within an international consortium on a 1.5T MR-Linac system with ultrahypofractionated radiotherapy. Materials & Methods: Patients treated with 5x7.25 Gray were identified within the registry. Prostate Specific Antigen (PSA), Common Terminology Criteria for Adverse Events (CTCAE) and Patient Reported Outcome (PRO) using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ)-PR25, EORTC QLQ-C30 and the EuroQol EQ5D-5L were prospectively recorded at baseline and at 3 and 6 months follow-up (FU). Descriptive and pairwise comparative statistics were conducted. Results: One-hundred-and-fifty-six consecutive patients with localised PCa (13.2% low-, 77.2% intermediate-, and 9.6% high-risk [National Comprehensive Cancer Network risk groups]) were included. Thirty-one patients (19.9%) received neoadjuvant Androgen Deprivation Therapy (ADT). A significant decline of PSA in non-ADT patients was observed between baseline (median: 7.8 ng/mL), 3 months FU (median: 2.7 ng/ mL) and 6 months FU (median: 1.7 ng/mL) (p<0.001). No grade ≥3 Genitourinary (GU) and Gastrointestinal (GI) toxicity was reported (table). No significant deterioration of PRO scores were observed. The percentage of men reporting no difficulty getting or maintaining an erection remained constant throughout FU (44.4% at baseline, 40.0% at 3 months FU, and 42.9% at 6 months FU). Conclusions: Ultrahypofractionated 1.5T MR-Linac treatment of localised PCa is effective and safe (no grade ≥3 GU and GI toxicity). In the first 6 months following treatment, patients reported stable erectile function. No significant deterioration of PROs at 3- and 6-months FU was observed.
    • Magnetic resonance imaging and detection of metastases in prostate cancer: learning lessons from history.

      Hoyle, Alex P; Clarke, Noel W; The Christie and Salford Royal Hospitals, Manchester, UK (2017-06-08)
    • Magnetic resonance imaging in precision radiation therapy for lung cancer.

      Bainbridge, H; Salem, Ahmed; Tijssen, R; Dubec, Michael; Wetscherek, A; Van Es, C; Belderbos, J; Faivre-Finn, Corinne; McDonald, F; The Institute of Cancer Research and The Royal Marsden Hospital NHS Foundation Trust, London, UK (2017-12)
      Radiotherapy remains the cornerstone of curative treatment for inoperable locally advanced lung cancer, given concomitantly with platinum-based chemotherapy. With poor overall survival, research efforts continue to explore whether integration of advanced radiation techniques will assist safe treatment intensification with the potential for improving outcomes. One advance is the integration of magnetic resonance imaging (MRI) in the treatment pathway, providing anatomical and functional information with excellent soft tissue contrast without exposure of the patient to radiation. MRI may complement or improve the diagnostic staging accuracy of F-18 fluorodeoxyglucose position emission tomography and computerized tomography imaging, particularly in assessing local tumour invasion and is also effective for identification of nodal and distant metastatic disease. Incorporating anatomical MRI sequences into lung radiotherapy treatment planning is a novel application and may improve target volume and organs at risk delineation reproducibility. Furthermore, functional MRI may facilitate dose painting for heterogeneous target volumes and prediction of normal tissue toxicity to guide adaptive strategies. MRI sequences are rapidly developing and although the issue of intra-thoracic motion has historically hindered the quality of MRI due to the effect of motion, progress is being made in this field. Four-dimensional MRI has the potential to complement or supersede 4D CT and 4D F-18-FDG PET, by providing superior spatial resolution. A number of MR-guided radiotherapy delivery units are now available, combining a radiotherapy delivery machine (linear accelerator or cobalt-60 unit) with MRI at varying magnetic field strengths. This novel hybrid technology is evolving with many technical challenges to overcome. It is anticipated that the clinical benefits of MR-guided radiotherapy will be derived from the ability to adapt treatment on the fly for each fraction and in real-time, using 'beam-on' imaging. The lung tumour site group of the Atlantic MR-Linac consortium is working to generate a challenging MR-guided adaptive workflow for multi-institution treatment intensification trials in this patient group.
    • Magnetic resonance imaging in the management of suspected spinal canal disease in patients with known malignancy.

      Loughrey, Gareth J; Collins, Conor D; Todd, Susan M; Brown, Nicola M; Johnson, Richard J; Department of Diagnostic Radiology, Christie Hospital NHS Trust, Wilmslow Road, Withington, Manchester, UK. (2000-11)
      AIM: The aim of this study was to examine the spectrum of spinal canal disease in patients with known malignancy using magnetic resonance imaging (MRI). MATERIALS AND METHODS: One hundred and fifty-five patients underwent a total of 159 spinal MRI examinations over a three-year period. Patients were examined using a 1.0T magnet and a phased array surface spine coil. Sagittal T1 weighted spin echo and STIR sequences were routinely employed. Axial T1 and T2 weighted spin echo images were obtained at sites of identified pathology. Contrast enhanced sagittal and axial T1 weighted spin echo images were acquired when the unenhanced appearances did not correlate with the clinical findings or when the images suggested intradural or intramedullary disease. RESULTS: Malignant disease affecting the spinal cord or cauda equina was noted in 104/159 (65%) patients (extradural n= 78, intradural n= 20, intramedullary n= 7); one patient had evidence of both intradural and intramedullary deposits. Multiple levels of extradural cord/cauda equina compression were present in 18/78 patients (23%). The thoracic spine was the most frequently affected (74%). Bone elements were the major component of extradural compression in 11/78 patients (14%). Intradural metastases were multiple in 15/20 patients (75%). Four of the six solitary intramedullary metastases were situated in the conus medullaris. CONCLUSION: Magnetic resonance imaging of the entire spine is the investigation of choice in patients with known malignancy and suspected spinal canal disease. Contrast-enhanced images should be acquired when the unenhanced appearances do not correlate with the clinical findings or when they suggest intradural or intramedullary disease.Loughrey, G. J. (2000). Clinical Radiology55, 849-855.
    • Magnetic resonance imaging of anal cancer.

      Roach, S C; Hulse, Paul; Moulding, F J; Wilson, R; Carrington, Bernadette M; Department of Diagnostic Radiology, Christie Hospital, Manchester, UK. (2005-10)
      AIM: The purpose of this study was to evaluate the magnetic resonance imaging (MRI) appearances of primary and recurrent anal carcinoma, and to demonstrate the commonest patterns of local and distant disease spread. METHODS: A retrospective review was performed of 27 cases of biopsy-proven anal carcinoma, where MRI was used for primary staging (9 patients) or suspected recurrence (18 patients). Two oncological radiologists reviewed the MR images, following a standardized approach. The size, extent and signal characteristics of the anal tumour were documented. Metastatic disease spread to lymph nodes, viscera and bone was recorded. In all, 7 patients with recurrent disease underwent surgery and subsequent histological correlation was performed. RESULTS: Primary and recurrent tumours were of high signal intensity relative to skeletal muscle on T2-weighted images (T2WI), and of low to intermediate signal intensity on T1-weighted images (T1WI). Lymph node metastases were of similar signal intensity to the anal cancer. Recurrent tumours were more locally advanced than primary tumours and extended into adjacent organs and the pelvic skeleton. Recurrent lymph node disease involved perirectal, presacral and internal iliac nodes more commonly than did primary lymph node disease. CONCLUSION: MRI can be useful in the primary staging of bulky tumours or of those with a long craniocaudal extent. MR has a role in the preoperative evaluation and surgical planning of cases of recurrent disease following radiotherapy.
    • Magnetic resonance imaging of bone metastases: a diagnostic and screening technique.

      Downey, S E; Wilson, M; Boggis, C; Baildam, Andrew D; Howell, Anthony; Bundred, Nigel J; University Department of Surgery, University Hospital of South Manchester, UK. (1997-08)
    • Magnetic resonance imaging of primary vaginal carcinoma.

      Taylor, Malcolm B; Dugar, N; Davidson, Susan E; Carrington, Bernadette M; Department of Diagnostic Radiology, Christie Hospital NHS Trust, Withington, Manchester, UK. ben.taylor@christie-tr.nwest.nhs.uk (2007-06)
      AIMS: To describe the magnetic resonance imaging (MRI) features of vaginal carcinoma and to suggest a role for MRI in its management. MATERIALS AND METHODS: Twenty-five patients with primary vaginal carcinoma treated at our institution between 1996 and 2005 were included in the study. The MRI examinations were reviewed and tumour dimensions, signal characteristics and involvement of pelvic structures were documented, as were sites of enlarged lymph nodes and metastases. Details of patient treatment and outcome were obtained from the clinical notes. RESULTS: The median patient age was 54 years (range 31-86 years). Tumour maximum diameter ranged from 1.6-11.3 cm (mean 3.7 cm). Most tumours were of iso-intense signal to muscle on T1-weighted images and hyper-intense to muscle on T2-weighted images. Eighty-eight percent of patients had tumour extending beyond the vagina and 56% of patients had Figo stage III or above tumours. Sixteen patients were treated with radiotherapy (two with chemoradiotherapy), five with surgery and four with supportive care. Ten patients (40%) died of their disease during the study period. The MRI stage of the tumour correlated with survival. CONCLUSION: MRI identified over 95% of primary vaginal tumours in the present study, enabled radiological staging, which correlated with outcome, and provided information of use in treatment planning.
    • Magnetic resonance imaging screening in women at genetic risk of breast cancer: imaging and analysis protocol for the UK multicentre study. UK MRI Breast Screening Study Advisory Group.

      Brown, J; Buckley, D; Coulthard, A; Dixon, A; Dixon, J; Easton, D; Eeles, Rosalind; Evans, D Gareth R; Gilbert, F; Graves, M; et al. (2000-09)
      The imaging and analysis protocol of the UK multicentre study of magnetic resonance imaging (MRI) as a method of screening for breast cancer in women at genetic risk is described. The study will compare the sensitivity and specificity of contrast-enhanced MRI with two-view x-ray mammography. Approximately 500 women below the age of 50 at high genetic risk of breast cancer will be recruited per year for three years, with annual MRI and x-ray mammography continuing for up to 5 years. A symptomatic cohort will be measured in the first year to ensure consistent reporting between centres. The MRI examination comprises a high-sensitivity three-dimensional contrast-enhanced assessment, followed by a high-specificity contrast-enhanced study in equivocal cases. Multiparametric analysis will encompass morphological assessment, the kinetics of contrast agent uptake and determination of quantitative pharmacokinetic parameters. Retrospective analysis will identify the most specific indicators of malignancy. Sensitivity and specificity, together with diagnostic performance, diagnostic impact and therapeutic impact will be assessed with reference to pathology, follow-up and changes in diagnostic certainty and therapeutic decisions. Mammography, lesion localisation, pathology and cytology will be performed in accordance with the UK NHS Breast Screening Programme quality assurance standards. Similar standards of quality assurance will be applied for MR measurements and evaluation.
    • Magnetic resonance imaging sequence evaluation of an MR Linac system; early clinical experience

      Eccles, Cynthia L; Adair, SG; Bower, L; Hafeez, S; Herbert, T; Hunt, A; McNair, HA; Ofuya, M; Oelfke, U; Nill, S; et al. (2019)
      OBJECTIVES: To systematically identify the preferred magnetic resonance imaging (MRI) sequences following volunteer imaging on a 1.5 Tesla (T) MR-Linear Accelerator (MR Linac) for future protocol development. METHODS: Non-patient volunteers were recruited to a Research and Ethics committee approved prospective MR-only imaging study on a 1.5T MR Linac system. Volunteers attended 1-3 imaging sessions that included a combination of mDixon, T1w, T2w sequences using 2-dimensional (2D) and 3-dimensional (3D) acquisitions. Each sequence was acquired over 2-7 minutes and reviewed by a panel of 3 observers to evaluate image quality using a visual grading analysis based on a 4-point Likert scale. Sequences were acquired and modified iteratively until deemed fit for purpose (online image matching or re-planning) and all observers agreed they were suitable in 3 volunteers. RESULTS: 26 volunteers underwent 31 imaging sessions of six general anatomical regions. Images were acquired in one or two of six general anatomical regions: male pelvis (n = 9), female pelvis (n = 4), chestwall/breast (n = 5), lung/oesophagus (n = 5), abdomen (n = 3) and head and neck (n = 5). Images were acquired using a pre-defined exam-card that on average, included six sequences (range 2-10), with a maximum scan time of approximately one hour. The majority of observers preferred T2-weighted sequences. The thorax teams were the only groups to prefer T1-weighted imaging. CONCLUSIONS: An iterative process identified sequence agreement in all anatomical regions. These sequences will now be evaluated in patient volunteers. ADVANCES IN KNOWLEDGE: This manuscript is the first publication sharing the results of the first systematic selection of MRI sequences for use in on-board MRI-guided radiotherapy by end-users (therapeutic radiographers and clinical oncologists) in healthy volunteers.
    • Magnetic resonance imaging with Gadolinium-DTPA for assessment of bladder carcinoma and its response to treatment.

      Hawnaur, J M; Johnson, Richard J; Read, G; Isherwood, I; Department of Diagnostic Radiology, University of Manchester. (1993-05)
      Magnetic Resonance Imaging (MRI) with intravenous Gadolinium-DTPA (Gd-DTPA, Magnevist, Schering-AG) was performed in 44 patients, 32 with primary bladder carcinoma and 12 with suspected recurrence after treatment. Gd-DTPA often increased diagnostic confidence in the identification and staging of tumours confined to the bladder wall and was necessary to assess depth of bladder wall invasion when T2-weighted images were suboptimal. Enhancement after Gd-DTPA enabled distinction between necrotic and viable tumour and blood clot. There was little advantage in its use for tumours infiltrating perivesical fat or with metastases to lymph nodes or bone, in the absence of a fat suppression sequence. Gd-DTPA may therefore be useful in selected patients with tumours of Stage T3a or less in whom information about depth of bladder wall invasion is inadequately shown on pre-contrast sequences. Artefacts due to variable and inhomogeneous urine signal intensity, however, often degraded post-Gd-DTPA images of the bladder. Changes in the bladder due to radiotherapy were observed on MRI 3-4 months after treatment in patients referred for routine follow-up and in some patients with suspected recurrence. Mucosal hyperintensity, thickening and abnormal signal intensity of the muscular layers of the bladder wall, with enhancement after Gd-DTPA were demonstrated. Such changes obscured small volume or superficial recurrence of tumour after radiotherapy. Abnormal enhancement was also observed in pelvic organs and soft tissues irradiated several years earlier. Enhancement after Gd-DTPA does not therefore reliably distinguish between recurrent tumour and radiotherapy change.