Barnes, A., Alonzi, R., Blackledge, M., Charles-Edwards, G., Collins, D.J., Cook, G., Coutts, G., Goh, V., Graves, M., Kelly, C., et al.
(2018). UK quantitative WB-DWI technical workgroup: consensus meeting recommendations on optimisation, quality control, processing and analysis of quantitative whole-body diffusion-weighted imaging for cancer. The british journal of radiology,
Winfield, J.M., Poillucci, G., Blackledge, M.D., Collins, D.J., Shah, V., Tunariu, N., Kaiser, M.F. & Messiou, C.
(2018). Apparent diffusion coefficient of vertebral haemangiomas allows differentiation from malignant focal deposits in whole-body diffusion-weighted MRI. European radiology,
Donners, R., Blackledge, M., Tunariu, N., Messiou, C., Merkle, E.M. & Koh, D.-.
(2018). Quantitative Whole-Body Diffusion-Weighted MR Imaging. Magnetic resonance imaging clinics of north america,
Winfield, J.M., Tunariu, N., Rata, M., Miyazaki, K., Jerome, N.P., Germuska, M., Blackledge, M.D., Collins, D.J., de Bono, J.S., Yap, T.A., et al.
(2017). Extracranial Soft-Tissue Tumors: Repeatability of Apparent Diffusion Coefficient Estimates from Diffusion-weighted MR Imaging. Radiology,
Purpose To assess the repeatability of apparent diffusion coefficient (ADC) estimates in extracranial soft-tissue diffusion-weighted magnetic resonance imaging across a wide range of imaging protocols and patient populations. Materials and Methods Nine prospective patient studies and one prospective volunteer study, performed between 2006 and 2016 with research ethics committee approval and written informed consent from each subject, were included in this single-institution study. A total of 141 tumors and healthy organs were imaged twice (interval between repeated examinations, 45 minutes to 10 days, depending the on study) to assess the repeatability of median and mean ADC estimates. The Levene test was used to determine whether ADC repeatability differed between studies. The Pearson linear correlation coefficient was used to assess correlation between coefficient of variation (CoV) and the year the study started, study size, and volumes of tumors and healthy organs. The repeatability of ADC estimates from small, medium, and large tumors and healthy organs was assessed irrespective of study, and the Levene test was used to determine whether ADC repeatability differed between these groups. Results CoV aggregated across all studies was 4.1% (range for each study, 1.7%-6.5%). No correlation was observed between CoV and the year the study started or study size. CoV was weakly correlated with volume (r = -0.5, P = .1). Repeatability was significantly different between small, medium, and large tumors (P < .05), with the lowest CoV (2.6%) for large tumors. There was a significant difference in repeatability between studies-a difference that did not persist after the study with the largest tumors was excluded. Conclusion ADC is a robust imaging metric with excellent repeatability in extracranial soft tissues across a wide range of tumor sites, sizes, patient populations, and imaging protocol variations. Online supplemental material is available for this article..
Weller, A., Papoutsaki, M.V., Waterton, J.C., Chiti, A., Stroobants, S., Kuijer, J., Blackledge, M., Morgan, V. & deSouza, N.M.
(2017). Diffusion-weighted (DW) MRI in lung cancers: ADC test-retest repeatability. European radiology,
Morone, M., Bali, M.A., Tunariu, N., Messiou, C., Blackledge, M., Grazioli, L. & Koh, D.-.
(2017). Whole-Body MRI: Current Applications in Oncology. American journal of roentgenology,
Koh, D.-., Lee, J.-., Bittencourt, L.K., Blackledge, M. & Collins, D.J.
(2016). Body Diffusion-weighted MR Imaging in Oncology. Magnetic resonance imaging clinics of north america,
Blackledge, M.D., Collins, D.J., Koh, D.-. & Leach, M.O.
(2016). Rapid development of image analysis research tools: Bridging the gap between researcher and clinician with pyOsiriX. Computers in biology and medicine,
O'Flynn, E.A., Blackledge, M., Collins, D., Downey, K., Doran, S., Patel, H., Dumonteil, S., Mok, W., Leach, M.O. & Koh, D.-., et al.
(2016). Evaluating the diagnostic sensitivity of computed diffusion-weighted MR imaging in the detection of breast cancer. Journal of magnetic resonance imaging,
Perez-Lopez, R., Lorente, D., Blackledge, M.D., Collins, D.J., Mateo, J., Bianchini, D., Omlin, A., Zivi, A., Leach, M.O., de Bono, J.S., et al.
(2016). Volume of Bone Metastasis Assessed with Whole-Body Diffusion-weighted Imaging Is Associated with Overall Survival in Metastatic Castration-resistant Prostate Cancer. Radiology,
Cheng, L., Blackledge, M.D., Collins, D.J., Orton, M.R., Jerome, N.P., Feiweier, T., Rata, M., Morgan, V., Tunariu, N., Leach, M.O., et al.
(2016). T2-adjusted computed diffusion-weighted imaging: A novel method to enhance tumour visualisation. Comp. in bio. and med.,
Cheng, L., Tunariu, N., Collins, D.J., Blackledge, M.D., Riddell, A.M., Leach, M.O., Popat, S. & Koh, D.-.
(2015). Response evaluation in mesothelioma: Beyond RECIST. Lung cancer,
Blackledge, M.D., Collins, D.J., Tunariu, N., Orton, M.R., Padhani, A.R., Leach, M.O. & Koh, D.-.
(2014). Assessment of treatment response by total tumor volume and global apparent diffusion coefficient using diffusion-weighted MRI in patients with metastatic bone disease: a feasibility study. Plos one,
We describe our semi-automatic segmentation of whole-body diffusion-weighted MRI (WBDWI) using a Markov random field (MRF) model to derive tumor total diffusion volume (tDV) and associated global apparent diffusion coefficient (gADC); and demonstrate the feasibility of using these indices for assessing tumor burden and response to treatment in patients with bone metastases. WBDWI was performed on eleven patients diagnosed with bone metastases from breast and prostate cancers before and after anti-cancer therapies. Semi-automatic segmentation incorporating a MRF model was performed in all patients below the C4 vertebra by an experienced radiologist with over eight years of clinical experience in body DWI. Changes in tDV and gADC distributions were compared with overall response determined by all imaging, tumor markers and clinical findings at serial follow up. The segmentation technique was possible in all patients although erroneous volumes of interest were generated in one patient because of poor fat suppression in the pelvis, requiring manual correction. Responding patients showed a larger increase in gADC (median change = +0.18, range = -0.07 to +0.78 × 10(-3) mm2/s) after treatment compared to non-responding patients (median change = -0.02, range = -0.10 to +0.05 × 10(-3) mm2/s, p = 0.05, Mann-Whitney test), whereas non-responding patients showed a significantly larger increase in tDV (median change = +26%, range = +3 to +284%) compared to responding patients (median change = -50%, range = -85 to +27%, p = 0.02, Mann-Whitney test). Semi-automatic segmentation of WBDWI is feasible for metastatic bone disease in this pilot cohort of 11 patients, and could be used to quantify tumor total diffusion volume and median global ADC for assessing response to treatment..
Andreou, A., Koh, D.M., Collins, D.J., Blackledge, M., Wallace, T., Leach, M.O. & Orton, M.R.
(2013). Measurement reproducibility of perfusion fraction and pseudodiffusion coefficient derived by intravoxel incoherent motion diffusion-weighted MR imaging in normal liver and metastases. Eur radiol,
OBJECTIVE: To determine the measurement reproducibility of perfusion fraction f, pseudodiffusion coefficient D and diffusion coefficient D in colorectal liver metastases and normal liver. METHODS: Fourteen patients with known colorectal liver metastases were examined twice using respiratory-triggered echo-planar DW-MRI with eight b values (0 to 900 s/mm(2)) 1 h apart. Regions of interests were drawn around target metastasis and normal liver in each patient to derive ADC (all b values), ADC(high) (b values ≥ 100 s/mm(2)) and intravoxel incoherent motion (IVIM) parameters f, D and D by least squares data fitting. Short-term measurement reproducibility of median ADC, ADC(high), f, D and D values were derived from Bland-Altman analysis. RESULTS: The measurement reproducibility for ADC, ADC(high) and D was worst in colorectal liver metastases (-21 % to +25 %) compared with liver parenchyma (-6 % to +8 %). Poor measurement reproducibility was observed for the perfusion-sensitive parameters of f (-75 % to +241 %) and D (-89 % to +2,120 %) in metastases, and to a lesser extent the f (-24 % to +25 %) and D (-31 % to +59 %) of liver. CONCLUSIONS: Estimates of f and D derived from the widely used least squares IVIM fitting showed poor measurement reproducibility. Efforts should be made to improve the measurement reproducibility of perfusion-sensitive IVIM parameters..
Koh, D.-., Tunariu, N., Blackledge, M. & Collins, D.J.
(2013). Competing Technology for PET/Computed Tomography. Pet clinics,
Blackledge, M.D., Koh, D.M., Collins, D.J., Chua, S. & Leach, M.O.
(2013). The utility of whole-body diffusion-weighted MRI for delineating regions of interest in PET. Nuclear instruments & methods in physics research section a-accelerators spectrometers detectors and associated equipment,
Koh, D.-., Blackledge, M., Padhani, A.R., Takahara, T., Kwee, T.C., Leach, M.O. & Collins, D.J.
(2012). Whole-body diffusion-weighted MRI: tips, tricks, and pitfalls. Ajr am j roentgenol,
OBJECTIVE: We examine the clinical impetus for whole-body diffusion-weighted MRI and discuss how to implement the technique with clinical MRI systems. We include practical tips and tricks to optimize image quality and reduce artifacts. The interpretative pitfalls are enumerated, and potential challenges are highlighted. CONCLUSION: Whole-body diffusion-weighted MRI can be used for tumor staging and assessment of treatment response. Meticulous technique and knowledge of potential interpretive pitfalls will help to avoid mistakes and establish this modality in radiologic practice..
Koh, D.-., Blackledge, M., Burns, S., Hughes, J., Stemmer, A., Kiefer, B., Leach, M.O. & Collins, D.J.
(2012). Combination of chemical suppression techniques for dual suppression of fat and silicone at diffusion-weighted MR imaging in women with breast implants. Eur radiol,
OBJECTIVES: Silicone breast prostheses prove technically challenging when performing diffusion-weighted MR imaging in the breasts. We describe a combined fat and chemical suppression scheme to achieve dual suppression of fat and silicone, thereby improving the quality of diffusion-weighted images in women with breast implants. METHODS: MR imaging was performed at 3.0 and 1.5 T in women with silicone breast implants using short-tau inversion recovery (STIR) fat-suppressed echo-planar (EPI) diffusion-weighted MR imaging (DWI) on its own and combined with the slice-select gradient-reversal (SSGR) technique. Imaging was performed using dedicated breast imaging coils. RESULTS: Complete suppression of the fat and silicone signal was possible at 3.0 T using EPI DWI with STIR and SSGR, evaluated with dedicated breast coils. However, a residual silicone signal was still perceptible at 1.5 T using this combined approach. Nevertheless, a further reduction in silicone signal at 1.5 T could be achieved by employing thinner slice partitions and the addition of the chemical-selective fat-suppression (CHESS) technique. CONCLUSIONS: DWI using combined STIR and SSGR chemical suppression techniques is feasible to eliminate or reduce silicone signal from prosthetic breast implants. KEY POINTS: Breast magnetic resonance imaging (MRI) is frequently needed following breast implants. Unsuppressed signal from silicone creates artefacts on diffusion-weighted MR sequences. Dual fat/chemical suppression can eliminate signal from fat and silicone. STIR with slice selective gradient reversal can suppress fat and silicone signal..
Blackledge, M.D., Leach, M.O., Collins, D.J. & Koh, D.-.
(2011). Computed diffusion-weighted MR imaging may improve tumor detection. Radiology,
PURPOSE: To describe computed diffusion weighted (DW) magnetic resonance (MR) imaging as a method for obtaining high-b-value images from DW MR imaging performed at lower b values and to investigate the feasibility of the technique to improve lesion detection in oncologic cases. MATERIALS AND METHODS: The study was approved by the institutional and research committee, and written informed consent was obtained from all patients. DW MR imaging was performed on a CuSO(4) phantom at 1.5 T with a range of b values and compared with computed DW MR imaging images synthesized from lower b values (0 and 600 sec/mm(2)). The signal-to-noise ratio (SNR) was compared, and agreement between the SNR of computed DW MR imaging and theoretical estimation assessed. Computed DW MR imaging was evaluated in 10 oncologic patients who underwent whole-body DW MR imaging with b values of 0 and 900 sec/mm(2). Computed DW MR images at computed b values of 1500 and 2000 sec/mm(2) were generated. The image quality and background suppression of acquired and computed images were rated by a radiologist using a four-point scale. The diagnostic performance for malignant lesion detection using these images was evaluated and compared by using the McNemar Test. RESULTS: The SNR of computed DW MR imaging of the phantom conformed closely to theoretical predictions. Computed DW MR imaging resulted in a higher SNR compared with acquired DW MR imaging, especially at b values greater than 840 sec/mm(2). In patients, images with a computed b value of 2000 sec/mm(2) produced good image quality and high background suppression (mean scores of 2.8 and 4.0, respectively). Evaluation of images with a computed b value of 2000 sec/mm(2) resulted in higher overall diagnostic sensitivity (96.0%) and specificity (96.6%) compared with images with an acquired b value of 900 sec/mm(2) (sensitivity, 89.4%; specificity, 87.5%; P < .01). CONCLUSION: Computed DW MR imaging in the body allows higher-b-value images to be obtained with a good SNR. Clinical computed DW MR imaging is feasible and may improve disease detection. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.11101919/-/DC1..
Kyriazi, S., Blackledge, M., Collins, D.J. & Desouza, N.M.
(2010). Optimising diffusion-weighted imaging in the abdomen and pelvis: comparison of image quality between monopolar and bipolar single-shot spin-echo echo-planar sequences. Eur radiol,
OBJECTIVE: To compare geometric distortion, signal-to-noise ratio (SNR), apparent diffusion coefficient (ADC), efficacy of fat suppression and presence of artefact between monopolar (Stejskal and Tanner) and bipolar (twice-refocused, eddy-current-compensating) diffusion-weighted imaging (DWI) sequences in the abdomen and pelvis. MATERIALS AND METHODS: A semiquantitative distortion index (DI) was derived from the subtraction images with b = 0 and 1,000 s/mm(2) in a phantom and compared between the two sequences. Seven subjects were imaged with both sequences using four b values (0, 600, 900 and 1,050 s/mm(2)) and SNR, ADC for different organs and fat-to-muscle signal ratio (FMR) were compared. Image quality was evaluated by two radiologists on a 5-point scale. RESULTS: DI was improved in the bipolar sequence, indicating less geometric distortion. SNR was significantly lower for all tissues and b values in the bipolar images compared with the monopolar (p < 0.05), whereas FMR was not statistically different. ADC in liver, kidney and sacrum was higher in the bipolar scheme compared to the monopolar (p < 0.03), whereas in muscle it was lower (p = 0.018). Image quality scores were higher for the bipolar sequence (p ≤ 0.025). CONCLUSION: Artefact reduction makes the bipolar DWI sequence preferable in abdominopelvic applications, although the trade-off in SNR may compromise ADC measurements in muscle..
Koh, D.-., Blackledge, M., Collins, D.J., Padhani, A.R., Wallace, T., Wilton, B., Taylor, N.J., Stirling, J.J., Sinha, R., Walicke, P., et al.
(2009). Reproducibility and changes in the apparent diffusion coefficients of solid tumours treated with combretastatin A4 phosphate and bevacizumab in a two-centre phase I clinical trial. Eur radiol,
The purpose was to determine the reproducibility of apparent diffusion coefficient (ADC) measurements in a two-centre phase I clinical trial; and to track ADC changes in response to the sequential administration of the vascular disrupting agent, combretastatin A4 phosphate (CA4P), and the anti-angiogenic drug, bevacizumab. Sixteen patients with solid tumours received CA4P and bevacizumab treatment. Echo-planar diffusion-weighted MRI was performed using six b values (b = 0-750 s/mm(2)) before (x2), and at 3 and 72 h after a first dose of CA4P. Bevacizumab was given 4 h after a second dose of CA4P, and imaging performed 3 h post CA4P and 72 h after bevacizumab treatment. The coefficient of repeatability (r) of ADC total (all b values), ADC high (b = 100-750) and ADC low (b = 0-100) was calculated by Bland-Altman analysis. The ADC total and ADC high showed good measurement reproducibility (r% = 13.3, 14.1). There was poor reproducibility of the perfusion-sensitive ADC low (r% = 62.5). Significant increases in the median ADC total and ADC high occurred at 3 h after the second dose of CA4P (p < 0.05). ADC measurements were highly reproducible in a two-centre clinical trial setting and appear promising for evaluating the effects of drugs that target tumour vasculature..
Blackledge, M.D., Tunariu, N., Orton, M.R., Padhani, A.R., Collins, D.J., Leach, M.O. & Koh, D.-.
Inter- and Intra-Observer Repeatability of Quantitative Whole-Body, Diffusion-Weighted Imaging (WBDWI) in Metastatic Bone Disease. Plos one,
Leach, M., Mossop, H., Blackledge, M., Rata, M., McDonald, A., Rescigno, P., Zafeiriou, Z., Porta, N., Hall, E., De Bono, J., et al.
Diffusion-weighted imaging as a treatment response biomarker evaluating bone metastases in prostate cancer. Radiology,
Hill, D.K., Heindl, A., Zormpas-Petridis, K., Collins, D.J., Euceda, L.R., Rodrigues, D.N., Moestue, S.A., Jamin, Y., Koh, D.-., Yuan, Y., et al.
Non-Invasive Prostate Cancer Characterization with Diffusion-Weighted MRI: Insight from In silico Studies of a Transgenic Mouse Model. Frontiers in oncology,