N M deSouza

Publications (48)138.18 Total impact

• Article: Characterisation of mobile lipid resonances in tissue biopsies from patients with cervical cancer and correlation with cytoplasmic lipid droplets.

  D Zietkowski, N M Desouza, R L Davidson, G S Payne
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  ABSTRACT: The aims of this study were to characterise the major saturated and unsaturated lipid peaks in histologically normal cervical epithelium and stroma, dysplastic epithelium (low-grade cervical intraepithelial neoplasia, CIN) and cancer-containing tissue samples from patients with cervical cancer using diffusion-weighted (1) H high-resolution magic angle spinning MRS, to determine whether mobile lipid resonances (MLRs) distinguish tissue types and to test for a correlation between MLRs and the number of cytoplasmic lipid droplets. Diffusion-weighted spectra of tissue biopsies were acquired using a stimulated echo sequence with bipolar gradients. Major saturated and unsaturated MLRs were identified and multivariate analysis of peak combinations was used to determine the best separation between tissue classes. Lipid droplets were visualised with Nile red staining and fluorescence microscopy. Correlations of saturated lipid resonances (0.9 and 1.3 ppm), polyunsaturated resonances (2.8 ppm), triglycerides (4.3 ppm) and unsaturated resonances (5.3 ppm) with average droplet number (per image) were investigated using a Spearman rank test. A large heterogeneity in lipid content among samples was observed, resulting in no significant differences in MLR intensities of individual peaks between the three tissue classes. Linear discriminant analysis separated 'no cancer' from 'cancer' based on the intensities at 0.9, 1.3, 2.2 and 2.8 ppm [area under the curve (AUC) = 0.939, p < 0.001], 'low-grade CIN' from 'cancer' based on the intensities at 0.9, 4.1, 4.3 and 5.3 ppm (AUC = 0.987, p < 0.001) and 'no cancer' from 'low-grade CIN' based on intensities at 0.9, 2.2 and 4.3 ppm (AUC = 0.984, p < 0.001). The distribution of cytoplasmic lipid droplets was nonuniform and was not related to the presence of epithelial or stromal components. On average, there were more droplets visible in low-grade CIN and cancer-containing tissues. Significant correlations between MLR peaks and lipid droplet number were seen for 0.9 (p = 0.002), 1.3 (p = 0.003) and 2.8 ppm (p = 0.018). MLR combinations indicative of average lipid structure efficiently separated tissue classes. Increased lipid resonances correlated with increased numbers of cytoplasmic lipid droplets. Copyright © 2013 John Wiley & Sons, Ltd.
  NMR in Biomedicine 02/2013; · 3.21 Impact Factor
• Article: Assessing response of myeloma bone disease with diffusion-weighted MRI.

  C Messiou, S Giles, D J Collins, S West, F E Davies, G J Morgan, N M Desouza
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  ABSTRACT: Objectives To measure apparent diffusion coefficient (ADC) values in patients with active myeloma and remission and to determine whether changes differ in those responding/progressing on treatment. The relationship between changes in marrow fat and ADC was also explored. Methods 20 patients were recruited. T(1 )weighted, T(2) weighted, short tau inversion-recovery, diffusion-weighted and two-point Dixon MRI of the lumbar spine and pelvis were performed at baseline, 4-6 weeks and 20 weeks. Results ADC values of active disease (mean 761.2±255×10(-6) mm(2) s(-1)) were significantly higher (p=0.047) than marrow in remission (mean 601.8±459×10(-6) mm(2) s(-1)). Changes in ADC in responders showed a significant increase at 4-6 weeks (p=0.005) but no significant change between baseline and 20 weeks (p=0.733). ADCs in progressing and stable patients did not change significantly between either time point. Pearson's correlation coefficient between change in fat fraction and change in the number of pixels with an ADC of ≤655×10(-6) mm(2) s(-1) was 0.924, indicating a significant correlation (p<0.001). Conclusion ADC values in active myeloma are significantly higher than marrow in remission, indicating the potential for diffusion-weighted MRI to quantify the transition from active disease to remission and vice versa. This study confirms significant changes in ADC in patients responding to treatment and indirect evidence from two-point Dixon MRI suggests that these changes are influenced by changes in marrow fat. Advances in knowledge ADC of active myeloma is significantly higher than marrow in remission; the direction of ADC changes on treatment is dependent on the timing of measurements and is influenced by changes in marrow fat.
  The British journal of radiology 12/2012; 85(1020):e1198-203. · 2.11 Impact Factor
• Article: Optimising diffusion weighted MRI for imaging metastatic and myeloma bone disease and assessing reproducibility.

  C Messiou, D J Collins, V A Morgan, N M Desouza
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  ABSTRACT: To establish normal bone marrow values of apparent diffusion coefficient (ADC) over an age range, compare them with metastatic and myelomatous involvement, to establish reproducibility and to optimise b values. The ADCs of bone marrow in 7 volunteers (mean age 29.7 years), 34 volunteers (mean age 63.3 years) and 43 patients with metastatic and myelomatous involvement (mean age 65.5 years) were measured. In 9 volunteers diffusion weighted MRI was repeated within 7 days. b values were derived to optimise contrast between normal and pathological marrow. The mean ADC of bone marrow in younger volunteers was significantly higher than that of older volunteers. The coefficient of reproducibility was 14.8%. The ADC mean of metastatic and myeloma bone disease was 1054 + / -456 x 10⁻⁶mm²s⁻¹. An ADC threshold of 655 × 10(-6) mm(2)s(-1) separated normal and abnormal marrow with a sensitivity and specificity of 90% and 93% respectively. Contrast between normal and abnormal marrow was optimal at b = 1389 smm(-2). The reproducibility of ADC measurements in bone is equivalent to published data for soft tissue with a high sensitivity and specificity for separating abnormal from age matched normal bone marrow. A b value of around 1,400 smm(-2) is optimal for imaging bone marrow.
  European Radiology 04/2011; 21(8):1713-8. · 3.22 Impact Factor
• Article: Diffusion-weighted magnetic resonance imaging for monitoring prostate cancer progression in patients managed by active surveillance.

  V A Morgan, S F Riches, K Thomas, N Vanas, C Parker, S Giles, N M Desouza
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  ABSTRACT: We studied patients managed by active surveillance to determine whether there was a difference over time in apparent diffusion coefficients (ADCs) derived from diffusion-weighted MRI in those who progressed to radical treatment (progressors, n = 17) compared with those who did not (non-progressors, n = 33). 50 consecutive patients (Stage T1/2a, Gleason grade ≤ 3+4, prostate-specific antigen (PSA) <15 ng ml⁻¹, <50% cores positive) were imaged endorectally (baseline and 1-3 years follow-up) with T₂ weighted (T₂W) and echo-planar diffusion-weighted MRI sequences. Regions of interest drawn on ADC maps with reference to the T₂W images yielded ADC(all) (b = 0-800), ADC(fast) (b = 0-300) and ADC(slow) (b = 300-800) for whole prostate (minus tumour) and tumour (low signal-intensity peripheral zone lesion in biopsy-positive octant). Tumour and whole prostate ADC(all) and ADC(fast) were significantly reduced over time in progressors (p = 0.03 and 0.03 for tumours, respectively; p = 0.02 and 0.007 for the whole prostate, respectively). There were no significant changes in ADC over time in non-progressors. A 10% reduction in tumour ADC(all) indicated progression with a 93% sensitivity and 40% specificity (A(z) of receiver operating characteristic (ROC) curve = 0.68). Percentage reductions in whole prostate ADC(all), ADC(fast) and ADC(slow) were also significantly greater in progressors than in non-progressors (p = 0.01, 0.03 and 0.008, respectively). This pilot study shows that DW-MRI has potential for monitoring patients with early prostate cancer who opt for active surveillance.
  The British journal of radiology 01/2011; 84(997):31-7. · 2.11 Impact Factor
• Article: Quantifying sclerotic bone metastases with 2D ultra short TE MRI: a feasibility study.

  C Messiou, D J Collins, V A Morgan, M D Robson, J S deBono, G M Bydder, N M deSouza
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  ABSTRACT: Ultra Short TE MRI allows signal to be detected from tissues with a very short T2.The aims of this study were to optimize a 2D UTE MRI sequence for imaging and quantification of sclerotic bone metastases, establish T2* values of sclerotic components and investigate the feasibility of using the method to assess changes in T2* of sclerotic metastases and their relation to attenuation values in patients on treatment. Twenty-two subjects were recruited in 3 cohorts. Cohort 1 was used to optimize the 2-D UTE sequence, cohort 2 was used to establish T2* measurements using a range of TEs and cohort 3 was used to assess T2* changes with treatment response and relate them to changes on electron density as measured by CT Hounsfield Units. Sagittal 2D UTE MRI of the lumbar spine is feasible demonstrating short T2 components in normal volunteers. In patients with bone metastases secondary to prostate carcinoma T2* can be measured and mean T2* of sclerotic metastases measured with TEs of 0.07, 0.27, 0.47 and 0.67 ms was 8.5 ms.T2* shortened by 20.0% in responders and increased by 24.4% in progressors. The significant linear relationship between percentage change in T2* as derived from UTE MRI and percentage change in HU from corresponding CT studies is indirect evidence that they are measuring effects of the same process.If the relationship between T2* and electron density holds true in further studies it offers potential for MR guided radiotherapy planning as well as attenuation correction for PET/MRI.
  Cancer biomarkers: section A of Disease markers 01/2010; 7(4):211-8. · 1.08 Impact Factor
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  Available from: icr.ac.uk

  Article: Diffusion Weighted Magnetic Resonance Imaging of metastatic bone disease: A biomarker for treatment response monitoring.

  C Messiou, N M deSouza
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  ABSTRACT: Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) combined with conventional MRI can provide a whole body assessment of metastatic bone disease, improved lesion detection compared to other imaging techniques and a direct quantitative assessment of treatment response. In bone marrow, the presence of fat and bone trabeculae and their changing contributions with disease progression and response to treatment present unique challenges for data acquisition and image interpretation. This article discusses these challenges and reviews the potential of DW-MRI to provide a biomarker of response in metastatic bone disease.
  Cancer biomarkers: section A of Disease markers 01/2010; 6(1):21-32. · 1.08 Impact Factor
• Article: Detection of cancer in cervical tissue biopsies using mobile lipid resonances measured with diffusion-weighted (1)H magnetic resonance spectroscopy.

  D Zietkowski, R L Davidson, T R Eykyn, S S De Silva, N M Desouza, G S Payne
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  ABSTRACT: The purpose of this study was to implement a diffusion-weighted sequence for visualisation of mobile lipid resonances (MLR) using high resolution magic angle spinning (HR-MAS) (1)H MRS and to evaluate its use in establishing differences between tissues from patients with cervical carcinoma that contain cancer from those that do not. A stimulated echo sequence with bipolar gradients was modified to allow T(1) and T(2) measurements and optimised by recording signal loss in HR-MAS spectra as a function of gradient strength in model lipids and tissues. Diffusion coefficients, T(1) and apparent T(2) relaxation times were measured in model lipid systems. MLR profiles were characterised in relation to T(1) and apparent T(2) relaxation in human cervical cancer tissue samples. Diffusion-weighted (DW) spectra of cervical biopsies were quantified and peak areas analysed using linear discriminant analysis (LDA). The optimised sequence reduced spectral overlap by suppressing signals originating from low molecular weight metabolites and non-lipid contributions. Significantly improved MLR visualisation allowed visualisation of peaks at 0.9, 1.3, 1.6, 2.0, 2.3, 2.8, 4.3 and 5.3 ppm. MLR analysis of DW spectra showed at least six peaks arising from saturated and unsaturated lipids and those arising from triglycerides. Significant differences in samples containing histologically confirmed cancer were seen for peaks at 0.9 (p < 0.006), 1.3 (p < 0.04), 2.0 (p < 0.03), 2.8 (p < 0.003) and 4.3 ppm (p < 0.0002). LDA analysis of MLR peaks from DW spectra almost completely separated two clusters of cervical biopsies (cancer, 'no-cancer'), reflecting underlying differences in MLR composition. Generated Receiver Operating Characteristic (ROC) curves and calculated area under the curve (0.962) validated high sensitivity and specificity of the technique. Diffusion-weighting of HR-MAS spectroscopic sequences is a useful method for characterising MLR in cancer tissues and displays an accumulation of lipids arising during tumourigenesis and an increase in the unsaturated lipid and triglyceride peaks with respect to saturated MLR.
  NMR in Biomedicine 12/2009; 23(4):382-90. · 3.21 Impact Factor
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  Available from: PubMed Central

  Article: Imaging metastatic bone disease from carcinoma of the prostate.

  C Messiou, G Cook, N M deSouza
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  ABSTRACT: Imaging bone metastases from prostate cancer presents several challenges. The lesions are usually sclerotic and appear late on the conventional X-ray. Bone scintigraphy is the mainstay of lesion detection, but is often not suitable for assessment of treatment response, particularly because of a 'flare' phenomenon after therapy. Magnetic resonance imaging is increasingly used in assessment, and newer techniques allow quantitation. In addition to (18)F-fluorodeoxyglucose ((18)FDG), newer PET isotopes are also showing promise in lesion detection and response assessment. This article reviews the available imaging modalities for evaluating prostatic bony metastases, and links them to the underlying pathological changes within bone lesions.
  British Journal of Cancer 09/2009; 101(8):1225-32. · 5.04 Impact Factor
• Article: Combined MRI and fibreoptic colonoscopy: technical considerations and clinical feasibility

  N. M. Desouza, G. A. Courts, D. J. Larkman, D. J. Gilderdale, A. D. Williams, A. Thillainagayam, I. R. Young
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  ABSTRACT: A method of fibre-optic colonoscopy with simultaneous high resolution MRI has been developed to obtain cross-sectional information of the intramural and extramural extent of lesions, for diagnostic and therapeutic purposes. An MR-compatible colonoscope with receiver coil was designed, developed and used in ex vivo studies to scan a section of large bowel in transverse and longitudinal planes with T1 and T2 weighted spin-echo sequences. In vivo five patients were followed-up after excision of large bowel cancer. The patients were three men and two women aged 50-77 years, (mean 65.6 years) who were studied on a 0.5 T scanner (Picker Asset, OH, USA). The coil and colonoscope were inserted into the rectum. After routine visual inspection of the colon, T1 weighted spin-echo images and radio-frequency spoiled gradient-echo images of the bowel wall were obtained. Ex vivo: three layers of bowel wall were identified: an intermediate to high signal-intense mucosa, a high signal intensity layer on T1 weighting which corresponded to the submucosa, and a low signal intensity muscularis propria. In vivo: On T1 weighted images three layers could be identified that corresponded to the layers seen on the ex vivo imaging. This pilot study demonstrates that MR colonoscopy is feasible and allows delineation of bowel wall structure, thus providing a useful adjunct to conventional colonscopy.
  07/2009; 9(1):25-30.
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  Available from: icr.ac.uk

  Article: Diffusion-weighted magnetic resonance imaging: a potential non-invasive marker of tumour aggressiveness in localized prostate cancer.

  N M deSouza, S F Riches, N J Vanas, V A Morgan, S A Ashley, C Fisher, G S Payne, C Parker
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  ABSTRACT: To evaluate diffusion-weighted magnetic resonance imaging (DW-MRI) as a marker for disease aggressiveness by comparing tumour apparent diffusion coefficients (ADCs) between patients with low- versus higher-risk localized prostate cancer. Forty-four consecutive patients classified as low- [n = 26, stageT1/T2a, Gleason score < or = 6, prostate-specific antigen (PSA)< 10 (group 1)] or intermediate/high- [n = 18, stage > or = T2b and/or Gleason score > or = 7, and/or PSA > 10 (group 2)] risk, who subsequently were monitored with active surveillance or started neoadjuvant hormone and radiotherapy, respectively, underwent endorectal MRI. T2-weighted (T2W) and DW images (5 b values, 0-800 s/mm(2)) were acquired and isotropic ADC maps generated. Regions of interest (ROIs) on T2W axial images [around whole prostate, central gland (CG), and tumour] were transferred to ADC maps. Tumour, CG, and peripheral zone (PZ = whole prostate minus CG and tumour) ADCs (fast component from b = 0-100 s/mm(2), slow component from b = 100-800 s/mm(2)) were compared. T2W-defined tumour volume medians, and quartiles were 1.2 cm(3), 0.7 and 3.3 cm(3) (group 1); and 6 cm(3), 1.3 and 16.5 cm(3) (group 2). There were significant differences in both ADC(fast) (1778 +/- 264 x 10(-6) versus 1583 +/- 283 x 10(-6) mm(2)/s, p = 0.03) and ADC(slow) (1379 +/- 321 x 10(-6) versus 1196 +/- 158 x 10(-6) mm(2)/s, p = 0.001) between groups. Tumour volume (p = 0.002) and ADC(slow) (p = 0.005) were significant differentiators of risk group. Significant differences in tumour ADCs exist between patients with low-risk, and those with higher-risk localized prostate cancer. DW-MRI merits further study with respect to clinical outcomes.
  Clinical Radiology 07/2008; 63(7):774-82. · 1.95 Impact Factor
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  Available from: european-radiology.org

  Article: Detection of colorectal hepatic metastases using MnDPDP MR imaging and diffusion-weighted imaging (DWI) alone and in combination.

  D M Koh, G Brown, A M Riddell, E Scurr, D J Collins, S D Allen, I Chau, D Cunningham, N M deSouza, M O Leach, J E Husband
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  ABSTRACT: To compare the diagnostic accuracy of MnDPDP MR imaging and diffusion-weighted imaging (DWI), alone and in combination, for detecting colorectal liver metastases in patients with suspected metastatic disease. Thirty-three consecutive patients with suspected colorectal liver metastases underwent MR imaging. Three image sets (MnDPDP, DWI and combined MnDPDP and DWI) were reviewed independently by two observers. Lesions were scored on a five-point scale for malignancy and the areas (Az) under the receiver operating characteristic curves were calculated for each observer and image set. The sensitivity and specificity for lesion detection were calculated for each image set and compared. There were 83 metastases, 49 cysts and 1 haemangioma. Using the combined set resulted in the highest diagnostic accuracy for both observers (Az=0.94 and 0.96), with improved averaged sensitivity of lesion detection compared with the DWI set (p=0.01), and a trend towards improved sensitivity compared with the MnDPDP set (p=0.06). There was no difference in the averaged specificity using any of the three image sets (p>0.5). Combination of MnDPDP MR imaging and DWI resulted in the highest diagnostic accuracy and can increase sensitivity without loss in specificity.
  European Radiology 05/2008; 18(5):903-10. · 3.22 Impact Factor
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  Available from: icr.ac.uk

  Article: Evaluation of the potential of diffusion-weighted imaging in prostate cancer detection.

  V A Morgan, S Kyriazi, S E Ashley, N M DeSouza
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  ABSTRACT: Conventional T2-weighted (T2W) imaging alone has a poor sensitivity for prostate cancer detection. To evaluate combined T2W and diffusion-weighted magnetic resonance imaging (DW-MRI) versus T2W MRI alone for identifying tumor in patients with prostate cancer. Fifty-four consecutive patients with prostate cancer (46 stage 1 and 2, 8 stage 3) and sextant biopsies within the previous 3 months were studied. Endorectal MR images were analyzed by two radiologists (1 experienced, 1 trainee) blinded to patient information and histopathology. T2W images were scored first, followed by combined T2W and isotropic apparent diffusion coefficient (ADC) maps calculated from DW-MRI (b = 0, 300, 500, and 800 s/mm(2)). Gland apex, middle, and base for each side were scored negative, indeterminate, or positive for tumor. Imaging data for each sextant were compared with histology. Sensitivity, specificity, and interobserver agreement were calculated. Sensitivity and specificity for tumor identification significantly improved from 50% and 79.6% (T2W alone, experienced observer) to 73.2% and 80.8% (P<0.001), respectively. For the trainee observer, there was no improvement (44.3% and 72% T2W alone vs. 45.1% and 69.2% T2W plus ADC maps). Interobserver agreement was moderate for T2W imaging alone (kappa 0.51) and fair for T2W plus ADC maps (kappa 0.33). In an experienced observer, DW-MRI together with T2W imaging can significantly improve tumor identification in prostate cancer.
  Acta Radiologica 07/2007; 48(6):695-703. · 1.37 Impact Factor
• Article: Magnetic resonance imaging in prostate cancer: the value of apparent diffusion coefficients for identifying malignant nodules.

  N M desouza, S A Reinsberg, E D Scurr, J M Brewster, G S Payne
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  ABSTRACT: 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.
  The British journal of radiology 03/2007; 80(950):90-5. · 2.11 Impact Factor
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  Available from: PubMed Central

  Article: Use of neoadjuvant chemotherapy prior to radical hysterectomy in cervical cancer: monitoring tumour shrinkage and molecular profile on magnetic resonance and assessment of 3-year outcome.

  N M deSouza, W P Soutter, G Rustin, M M Mahon, B Jones, R Dina, G A McIndoe
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  ABSTRACT: The objective of this study is to assess tumour response to neoadjuvant chemotherapy prior to radical hysterectomy in cervical cancer using magnetic resonance (MR) to monitor tumour volume and changes in molecular profile and to compare the survival to that of a control group. Eligibility included Stage Ib-IIb previously untreated cervical tumours >10 cm(3). Neoadjuvant chemotherapy in 22 patients (methotrexate 300 mg x m(-2) (with folinic acid rescue), bleomycin 30 mg x m(-2), cisplatin 60 mg m(-2)) was repeated twice weekly for three courses and followed by radical hysterectomy. Post-operative radiotherapy was given in 14 cases. A total of 23 patients treated either with radical surgery or chemoradiotherapy over the same time period comprised the nonrandomised control group. MR scans before and after neoadjuvant chemotherapy and in the control group documented tumour volume on imaging and metabolites on in vivo spectroscopy. Changes were compared using a paired t-test. Survival was calculated using the Kaplan-Meier method. There were no significant differences between the neoadjuvant chemotherapy and control groups in age (mean, s.d. 43.3+/-10, 44.7+/-8.5 years, respectively, P=0.63) or tumour volume (medians, quartiles 35.8, 17.8, 57.7 cm(3) vs 23.0, 15.0, 37.0 cm(3), respectively, P=0.068). The reduction in tumour volume post-chemotherapy (median, quartiles 7.5, 3.0, 19.0 cm(3)) was significant (P=0.002). The reduction in -CH(2) triglyceride approached significance (P=0.05), but other metabolites were unchanged. The 3-year survival in the chemotherapy group (49.1%) was not significantly different from the control group (46%, P=0.94). There is a significant reduction in tumour volume and -CH(2) triglyceride levels after neoadjuvant chemotherapy, but there is no survival advantage.
  British Journal of Cancer 06/2004; 90(12):2326-31. · 5.04 Impact Factor
• Article: Adenomyoma mimicking an aggressive uterine neoplasm on MRI.

  A M Connors, N M deSouza, G A McIndoe
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  ABSTRACT: This case report concerns a nulliparous female with prolonged vaginal bleeding, where MRI demonstrated a mass with an aggressive, tumour like appearance involving the posterior aspect of the uterus. Histological examination confirmed that this was an adenomyoma. The unusual imaging appearance of this lesion and its differential diagnosis are discussed. Adenomyoma should be considered in the differential diagnosis of aggressive-appearing uterine masses.
  British Journal of Radiology 02/2003; 76(901):66-8. · 1.31 Impact Factor
• Article: Evaluation of dysfunction following reconstruction of an anorectal anomaly.

  M Hettiarachchi, G Garcea, N M deSouza, A D Williams, G S Clayden, H C Ward
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  ABSTRACT: To evaluate the utility of anorectal manometry (ARM) and magnetic resonance imaging (MRI) with an endocoil in the assessment of dysfunction in children with repaired anorectal anomalies (ARA), 15 patients aged 1 to 15 years with repaired ARAs and chronic faecal incontinence or constipation were prospectively recruited. They underwent clinical assessment using a modified Wingfield score (MWS). ARM and MRI with an endocoil and conventional external coil were carried out. The results of ARM alone, MRI alone, and a combination of ARM and MRI were correlated with the MWS. Manometric internal anal sphincter (IAS) scores determined from sphincter length and activity correlated with MWS (r = 0.56, P = 0.02); manometric scores of rectal peristaltic activity did not. Overall manometric score (IAS and rectal scores combined) showed a correlation with MWS (r = 0.55, P = 0.02). Endoanal MRI sphincter scores did not correlate with MWS, but the presence of a megarectum on MRI did (r = 0.44, P = 0.05). Overall MRI score did not correlate with MWS. Minor neurosacral anomalies were shown on MRI in 3 children who had poor functional scores. Combined manometric and MRI scores showed a correlation with MWS (r = 0.58, P = 0.01). ARM and MRI are potentially useful in the assessment of dysfunction of children with repaired ARAs. Both modalities require refinement and further assessment in the context of directing management.
  Pediatric Surgery International 10/2002; 18(5-6):405-9. · 1.25 Impact Factor
• Article: Resection of recurrent bulky gynaecological side wall malignancy with iliac vessel reconstruction.

  R J Gornall, N Standfield, N M deSouza, V R Aachi, G A McIndoe
  BJOG An International Journal of Obstetrics & Gynaecology 01/2002; 108(12):1305-8. · 3.41 Impact Factor
• Article: An investigation into the use of sensitivity-encoded techniques to increase temporal resolution in dynamic contrast-enhanced breast imaging.

  D J Larkman, N M deSouza, M Bydder, J V Hajnal
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  ABSTRACT: Gadolinium-enhanced dynamic magnetic resonance (MR) imaging is playing an increasingly important diagnostic role in patients with breast cancer. Because of the multi-focal nature of the disease, it is mandatory to cover all of both breasts, not only in the initial scan, but also at subsequent follow-up. This requires volume acquisitions with a temporal resolution limited to 60-80 seconds, which is insufficient to clearly discriminate malignant from benign rates of contrast uptake. In this work, we performed sensitivity-encoded imaging using a commercially available four-channel breast coil (MRI Devices Corporation) on a commercial 0.5-T scanner with moderate gradient performance to give increased temporal resolution in these dynamic contrast-enhanced scans. A two-fold increase in temporal resolution was readily achievable with this coil. Image reconstruction was robust and image quality was assessed qualitatively to be good. We also investigated higher speed-up factors using two directions of sensitivity-encoded reduction and discussed some of the potential artifacts associated with such imaging.
  Journal of Magnetic Resonance Imaging 10/2001; 14(3):329-35. · 2.70 Impact Factor
• Article: Detection of pelvic lymph node metastases in gynecologic malignancy: a comparison of CT, MR imaging, and positron emission tomography.

  A D Williams, C Cousins, W P Soutter, M Mubashar, A M Peters, R Dina, F Fuchsel, G A McIndoe, N M deSouza
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  ABSTRACT: Accurate assessment of lymph node status before treatment is critical in the treatment of gynecologic cancers because the 5-year survival and treatment of women is influenced by lymph node involvement. The aims of this study were to investigate the ability of X-ray CT, MR imaging, and (18)F-FDG positron emission tomography (PET) to detect pelvic lymph node metastases by comparing imaging with histopathologic findings after lymph node dissection. Eighteen patients with gynecologic cancers were studied by all three imaging methods before surgery. The images were initially reviewed with routine diagnostic conditions and then, subsequently, by two observers who were unaware of the clinical and histopathologic findings of the patients. The nodal sites were split into upper (aortic to common iliac bifurcations) and lower (common iliac bifurcations to inguinal ligament) iliac chains. All observers' results were statistically analyzed with specificity, sensitivity, positive and negative predictive values, Fisher's exact test (individual observers) or chi-square test (combined observers), and Cohen's kappa test. Eight of 18 patients had lymph node metastases at histology. Findings of all three modalities agreed in full in only one patient. CT correctly revealed 10 node-negative patients, whereas MR imaging was correct in eight of these patients. (18)F-FDG PET correctly depicted one patient with lymph nodes negative for tumor. CT was the most specific imaging modality (97.0%), with MR imaging and PET rendering values of 90.7% and 77.3%, respectively, but sensitivity of all modalities was low (CT, 48.1%; MR imaging, 53.7%; PET, 24.5%). Observer agreement for each modality was good; kappa values among all observers were 0.88 for CT, 0.85 for MR imaging, and 0.72 for PET. CT is the most specific modality for detecting lymph nodes positive for tumor in gynecologic cancers, whereas MR imaging is the most sensitive. The poor results of PET in the pelvis are attributed to urinary (18)F-FDG in the ureters or bladder, which may mask or imitate lymph node metastases.
  American Journal of Roentgenology 09/2001; 177(2):343-8. · 2.78 Impact Factor
• Article: Catheter tracking for MR fluoroscopy: design of a transmit/receive coil for use with a nasogastric tube.

  D J Herlihy, D J Larkman, N M deSouza, A D Williams, I R Young
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  ABSTRACT: A coil tuned to 21.3 MHz was incorporated into a nasogastric tube and used as a marker of tube position during magnetic resonance (MR) imaging in a 0.5-T scanner. Catheter tracking was investigated with the coil used in both transmit/receive and in receive-only modes. Data acquired from this coil were overlaid on images obtained using the body coil of the scanner. Visualization of the full length of the catheter with local high signal at the tip was achieved with a temporal resolution of approximately 1 second. J. Magn. Reson. Imaging 2001;13:127-130.
  Journal of Magnetic Resonance Imaging 02/2001; 13(1):127-30. · 2.70 Impact Factor