title: Quantitative diffusion weighted MRI: a functional biomarker of nodal disease in Hodgkin lymphoma?
abstract: OBJECTIVE
  This study explores the relationship between MRI Apparent Diffusion Coefficient (ADC) and PET Standardized Uptake Value (SUV) measurements in pediatric Hodgkin lymphoma.
  
  
  METHODS
  Sixteen patients (mean age 15.4 yrs, 8 male) with proven Hodgkin lymphoma were recruited and staged using PET-CT, anatomical MRI and additional 1.5T diffusion weighted imaging (DWI) prior to and following chemotherapy. Pre-treatment lymph nodes and anatomically paired post-treatment residual tissue located on MRI were matched to the corresponding PET-CT. Region of interest (ROI) analysis was used to extract quantitative measurements. Mean ADC (ADC(mean)) and maximum SUV (SUV(max)) were recorded and correlation assessed using Spearman statistics.
  
  
  RESULTS
  Fifty-three ROIs were sampled. Pre- and post-treatment ADC(mean) ranged from 0.77 × 10(−3) to 1.79 × 10(−3) (median 1.15 × 10(−3) mm(2)s(−1)) and 1.08 × 10(−3) to 3.18 ×10(−3) (median 1.88 × 10(−3) mm(2)s(−1)), and SUV(max) from 2.60 to 25.4 (median 8.85 mg/ml) and 1.00 to 3.50 mg/ml (median 1.90 mg/ml). Median post-treatment ADC(mean) was higher, and median SUV(max) lower than pretreatment values (p < 0.0001). There was an inverse correlation between pre-treatment ADC(mean) and SUV(max) (p = 0.005) and between fractional change ([post-treatment – pre-treatment]/pre-treatment)in ADC(mean) and SUV(max) (p =0.002).
  
  
  CONCLUSIONS
  Our results confirm a strong reciprocal relationship between nodal ADC(mean) and SUV(max) in Hodgkin lymphoma;supporting the potential application of quantitative DWI as a functional biomarker of disease.
authors.affiliation: Department of Specialist Radiology, University College Hospital, London, UK. shonit.punwani@gmail.com
authors.forename: Shonit
authors.initials: S
authors.lastname: Punwani
authors.forename: Vineet
authors.initials: V
authors.lastname: Prakash
authors.forename: Alan
authors.initials: A
authors.lastname: Bainbridge
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Taylor
authors.forename: Steven
authors.initials: S
authors.lastname: Bandula
authors.forename: Oystein E
authors.initials: OE
authors.lastname: Olsen
authors.forename: Sharon F
authors.initials: SF
authors.lastname: Hain
authors.forename: Ananth
authors.initials: A
authors.lastname: Shankar
authors.forename: Stephen
authors.initials: S
authors.lastname: Daw
authors.forename: Paul
authors.initials: P
authors.lastname: Humphries
mesh_terms: D000293:Adolescent; D014408:Biomarkers, Tumor; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006689:Hodgkin Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography
chemical_list: D014408:Biomarkers, Tumor