Comparison of MRI and ultrasound based liver volumetry in iron overload diseases Poster No.: C-0913 Congress: ECR 2015 Type: Scientific Exhibit Authors: S. Keller, B. P. Schönnagel, P. Nielsen, M. T. Brehmer, C. Berliner, G. Adam, R. Fischer, J. Yamamura; Hamburg/DE Keywords: DOI: Abdomen, Hematologic, Liver, MR, Ultrasound, Imaging sequences, Statistics, Hematologic diseases 10.1594/ecr2015/C-0913 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 7
Aims and objectives Organ volume assessment is an important clinical task to evaluate therapeutic outcome and iron accumulation due to blood transfusions in patients with iron loading anemias such as thalassemia or with genetic hemochromatosis. Purpose of this study was to investigate the accuracy of liver volumen measurements using MR-volumetry and Ultasonic planimetry in a cohort of patients suffering hematological diseases and consecutive hepatomegaly. Furthermore age and physical constitution (body weight and body surface) normalized volume indices were calculated to generate disease individualized standard values. Methods and materials 56 controls and 109 patients suffering hematological diseases were examined using US- and MR-Volumetry. Bland Altman correlation analysis was performed to assess agreement of both technics. Interobserver and Intraobserver variability was assessed in 23 and 15 patients, respectively. Liver volumes of healthy patients in concordance to literature data (Rasmussen et al. 1987) were correlated to body surface area (BSA, m 2 and body weight, kg) and mean volume indices (ml/kg, ml/m 2 ) ± SD were calculated in the age, gender and disease specific cohorts. Images for this section: Page 2 of 7
Fig. 1: Volumetry by MRI (OsiriX software version v.5.8. 32 bit) and Ultrasound (US) in sagittal laser aligned probe positions. Page 3 of 7
Results US and MR measured liver volumes highly correlated (correlation coefficient 0.02, 95% CI 2.5-7.0, p<0.001). In contrast to Rasmussen et al. our sonographically assessed liver volumes were estimated slightly higher compared to the MR method, which might be caused by a greater dependence of observer-experience in ultrasound. Nevertheless all data obtained of liver volumes showed a high correlation and good intra- and interobservervariablity. In concordance with Rasmussen et al. (Rasmussen 1978 on page ) we found the best liver volume correlation to body surface area (BSA) compared to body weight (BW). Mean liver volumes obtained in our institution in healthy patients were slightly lower compared to obtained volumes of Rasmussen et al which might be explained by multifactorial causes like gender and age distribution, dietary habits and genetic influences. Whereas liver volume per bodyweight was increased in children compared to adolescents and young adults (p<0.01) this effect was blunted related to BSA indicating this volume index as more stable in different age groups. These finding is comparable to the study conducted by Saeki et al. (Saeki, et al. 2012 on page ) postulating a greater correlation of BSA and LV than BW especially due to greater group differences between <20 and >20 kg BW. It is worth to mention that there was no significant change in adult age- or gender specific groups. Normal 0 21 false false false EN-US JA X-NONE Images for this section: Page 4 of 7
Fig. 2: Comparison between ultrasound (US) and MRI volumetry of liver volumes by Altman-Bland plot in patients and normal subjects. Relative liver volume difference (US - MRI) with bias at 5.1±1.0 % (dashed-dotted line) and 95% limits of agreement from -21 to 31 % (dashed lines), n=165. Fig. 3: Liver volumes in normal subjects (circles, n=56) correlated (solid lines, dashed lines = 95% confidence range) with body surface area (r2 = 0.87) and body weight (r2 = 0.87) when forced through the average neonate data point (grey square) from Kuno et al (2002): a) power regression by body surface area Vliver = 783 BSA(1.10±0.03) Page 5 of 7
and b) by body weight Vliver = 57.3 BW(0.772±0.004). For comparison, data from S.N. Rasmussen (1978) are shown (triangles, n=134). Fig. 4: Relationship between liver volume indices (vliv) and age (circles, solid lines, dashed lines = 95% prediction range) in normal subjects with average neonate data point (grey square) from Kuno et al (2002): a) mean BSA based volume index of 815 ± 15 ml/ m2 is independent from age, and b) body weight based volume index relationship of age (r2 = 0.55) vlivi [ml/kg] = (21.5±0.6) exp((-0.133±0.020) age) + 21.4. For comparison, data from S.N. Rasmussen (1978) are shown (triangles). Page 6 of 7
Conclusion MR- and US-based liver Volumetry are reliable and robust methods to estimate organ volume in the daily clinical routine. Age and BSA normalized volume indices for the estimation of iron accumulation in the main iron storing organs due to therapeutic blood transfusions are good guidlines to facilitate follow up examinations and assess therapy response in hematological diseases. Personal information References 1968 Relationship between liver size and body size. Radiology 91(6):1195-8. 1978 Liver volume determination by ultrasonic scanning. Dan Med Bull 25(1):1-46. 1973 Spleen volume determination by ultrasonic scanning. Scand J Haematol 10(4):298-304. Normal 0 21 false false false EN-US JA X-NONE 2012 A formula for determining the standard liver volume in children: a special reference for neonates and infants. Pediatr Transplant 16(3):244-9. Page 7 of 7