242 AJR:205, August 2015 with ADC quantification for assessing treat- ment response to diseases involving bone marrow (e.g., in metastases from breast or prostate cancer [6] or in multiple myeloma [7, 8]). This evaluation is complicated by the considerable variability in signal intensity in the appearances of normal organs and, espe- cially, of bone marrow with sex, age, and nu- merous other factors [9]. It is therefore essential to establish the dis- tribution of normal ADC values for abdom- inal organs and bone marrow as calculated from perfusion-sensitive whole-body DWI protocols—herein referred to as “ADC ALL ”— and of normal ADC values for abdominal or- gans and bone marrow as calculated from perfusion-insensitive whole-body DWI pro- tocols—herein referred to as “ADC HIGH ”— and establish their dependency on variables such as sex, age, and FF; an understanding of Apparent Diffusion Coef fcient of Normal Abdominal Organs and Bone Marrow From Whole-Body DWI at 1.5 T: The Effect of Sex and Age Ioannis Lavdas 1 Andrea G. Rockall 2 Federica Castelli 3 Ranbir S. Sandhu 2 Annie Papadaki 4 Lesley Honeyfeld 2 Adam D. Waldman 2,5 Eric O. Aboagye 1 Lavdas I, Rockall AG, Castelli F, et al. 1 Department of Surgery and Cancer, Comprehensive Cancer Imaging Centre, Imperial College, Hammersmith Campus, DuCane Rd, London W12 0NN, UK. Address correspondence to I. Lavdas (ilavdas@imperial.ac.uk). 2 Imaging Department, Imperial College Healthcare NHS Trust, London, UK. 3 Istituto di Radiologia, Policlinico “G. B. Rossi,” Verona, Italy. 4 Radiological Sciences Unit, Imperial College Healthcare NHS Trust, Charing Cross Hospital, London, UK. 5 Department of Medicine, Division of Brain Sciences, Imperial College, London, UK. Special Articles • Original Research Supplemental Data Available online at www.ajronline.org. AJR 2015; 205:242–250 0361–803X/15/2052–242 © American Roentgen Ray Society E xtracranial applications of DWI have been facilitated by recent technologic developments—no- tably, high-performance gradi- ents, phased-array coils, and parallel imaging techniques—and are increasingly gaining popularity in oncology for diagnosis and treatment response monitoring [1]. Whole- body DWI in particular (originally referred to as “diffusion-weighted imaging with back- ground signal suppression” or “DWIBS” [2]) has now become a valuable diagnostic tool that provides at-a-glance assessment of local and metastatic disease burden, without the use of ionizing radiation. Whole-body DWI with apparent diffusion coefficient (ADC) quantification is also increasingly used for disease staging and treatment response moni- toring in involved organs [3–5]. There is a special interest in applying whole-body DWI Keywords: abdominal organs, bone marrow, normal apparent diffusion coef fcient (ADC), sex and age, whole-body DWI DOI:10.2214/AJR.14.13964 Received October 3, 2014; accepted after revision February 4, 2015. The Imperial College London Comprehensive Cancer Imaging Centre is funded by a 5-year joint grant (C2536/A10337) from Cancer Research UK, the Engineering & Physical Sciences Research Council, the Medical Research Council, and the Department of Health. OBJECTIVE. The objectives of this study were to define the range of apparent diffusion coefficients (ADCs) from whole-body DWI in normal abdominal organs and bone marrow, to identify ADC differences between sexes and changes occurring with age, and to evaluate the effect of the fat fraction (FF) on the ADC of normal liver parenchyma and bone marrow. MATERIALS AND METHODS. Fifty-one healthy volunteers (mean age = 38 years; age range = 23–68 years) underwent whole-body DWI using single-shot echo-planar imaging (b = 0, 150, 400, 750, and 1000 s/mm 2 ). A two-point Dixon technique was used to evaluate the FF. Perfusion-sensitive ADCs, which we refer to as “ADC ALL ,” and perfusion-insensitive ADCs, which we refer to as “ADC HIGH ,” of the liver and renal parenchyma, spleen, pancre- atic tail, and red and yellow bone marrow were calculated. The relationships between ADC and sex, age, and FF were examined. RESULTS. ADC ALL and ADC HIGH were significantly higher in female volunteers for the pancreatic tail (p = 0.046 and 0.008, respectively), red bone marrow (p = 0.029 and 0.001), and yellow bone marrow (p < 0.001 for both) but with considerable overlap. There were significant negative correlations between ADC ALL and ADC HIGH and age in the liver parenchyma (p = 0.008 and 0.01, respectively) and in the yellow bone marrow (p = 0.013 and 0.039) for all subjects. ADC ALL and ADC HIGH were also negatively correlated with FF in the liver parenchyma (p = 0.006 and 0.008, respectively) and in yellow bone marrow (p < 0.001 and p = 0.001) in all subjects. CONCLUSION. The ADCs of normal liver parenchyma and bone marrow change sig- nificantly with age. The ADCs of bone marrow in women are significantly higher than those of men and correlate strongly with FF. These effects may have an impact on image interpreta- tion when using whole-body DWI to assess disease burden and treatment response. Lavdas et al. 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