title: Automatic quantification of subarachnoid hemorrhage on noncontrast CT.
abstract: OBJECTIVE
  Quantification of blood after SAH on initial NCCT is an important radiologic measure to predict patient outcome and guide treatment decisions. In current scales, hemorrhage volume and density are not accounted for. The purpose of this study was to develop and validate a fully automatic method for SAH volume and density quantification.
  
  
  METHODS
  The automatic method is based on a relative density increase due to the presence of blood from different brain structures in NCCT. The method incorporates density variation due to partial volume effect, beam-hardening, and patient-specific characteristics. For validation, automatic volume and density measurements were compared with manual delineation on NCCT images of 30 patients by 2 radiologists. The agreement with the manual reference was compared with interobserver agreement by using the intraclass correlation coefficient and Bland-Altman analysis for volume and density.
  
  
  RESULTS
  The automatic measurement successfully segmented the hemorrhage of all 30 patients and showed high correlation with the manual reference standard for hemorrhage volume (intraclass correlation coefficient = 0.98 [95% CI, 0.96-0.99]) and hemorrhage density (intraclass correlation coefficient = 0.80 [95% CI, 0.62-0.90]) compared with intraclass correlation coefficient = 0.97 (95% CI, 0.77-0.99) and 0.98 (95% CI, 0.89-0.99) for manual interobserver agreement. Mean SAH volume and density were, respectively, 39.3 ± 31.5 mL and 62.2 ± 5.9 Hounsfield units for automatic measurement versus 39.7 ± 32.8 mL and 61.4 ± 7.3 Hounsfield units for manual measurement. The accuracy of the automatic method was excellent, with limits of agreement of -12.9-12.1 mL and -7.6-9.2 Hounsfield units.
  
  
  CONCLUSIONS
  The automatic volume and density quantification is very accurate compared with manual assessment. As such, it has the potential to provide important determinants in clinical practice and research.
authors.affiliation: From the Departments of Radiology (A.M.B., I.A.Z., R.v.d.B., H.A.M., C.B.M.) Biomedical Engineering and Physics (A.M.B., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands Institute of Technical Medicine (A.M.B.) a.m.boers@amc.uva.nl.
authors.forename: A M
authors.initials: AM
authors.lastname: Boers
authors.affiliation: From the Departments of Radiology (A.M.B., I.A.Z., R.v.d.B., H.A.M., C.B.M.).
authors.forename: I A
authors.initials: IA
authors.lastname: Zijlstra
authors.affiliation: Department of Neurology (C.S.G.), University Medical Centre Utrecht, Utrecht, the Netherlands.
authors.forename: C S
authors.initials: CS
authors.lastname: Gathier
authors.affiliation: From the Departments of Radiology (A.M.B., I.A.Z., R.v.d.B., H.A.M., C.B.M.).
authors.forename: R
authors.initials: R
authors.lastname: van den Berg
authors.affiliation: MIRA Institute for Biomedical Technology and Technical Medicine (C.H.S.), University of Twente, Enschede, the Netherlands.
authors.forename: C H
authors.initials: CH
authors.lastname: Slump
authors.affiliation: From the Departments of Radiology (A.M.B., I.A.Z., R.v.d.B., H.A.M., C.B.M.) Biomedical Engineering and Physics (A.M.B., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: H A
authors.initials: HA
authors.lastname: Marquering
authors.affiliation: From the Departments of Radiology (A.M.B., I.A.Z., R.v.d.B., H.A.M., C.B.M.).
authors.forename: C B
authors.initials: CB
authors.lastname: Majoie
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging; D002545:Brain Ischemia / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009485:Neuroradiography / Q000379:methods*; D015588:Observer Variation; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*
references.citation: IEEE Trans Med Imaging. 2010 Jan;29(1):196-205
references.pmid: 19923044
references.citation: Stroke. 2000 Aug;31(8):1843-50
references.pmid: 10926945
references.citation: Stroke. 1990 Aug;21(8):1156-61
references.pmid: 2389295
references.citation: Neurosurg Focus. 2006 Sep 15;21(3):E5
references.pmid: 17029344
references.citation: J Neurosurg. 1988 Jun;68(6):985-6
references.pmid: 3131498
references.citation: J Neurosurg. 1968 Jan;28(1):14-20
references.pmid: 5635959
references.citation: Lancet. 2007 Jan 27;369(9558):306-18
references.pmid: 17258671
references.citation: Magn Reson Imaging Clin N Am. 2006 May;14(2):127-40, v
references.pmid: 16873007
references.citation: Med Phys. 2011 Jul;38 Suppl 1:S36
references.pmid: 21978116
references.citation: Stroke. 2007 Aug;38(8):2315-21
references.pmid: 17569871
references.citation: Neurol Med Chir (Tokyo). 2011;51(3):187-94
references.pmid: 21441734
references.citation: Stroke. 1988 Oct;19(10):1250-6
references.pmid: 3176085
references.citation: Neurosurgery. 1985 Oct;17(4):609-12
references.pmid: 4058698
references.citation: AJNR Am J Neuroradiol. 1987 Nov-Dec;8(6):1049-55
references.pmid: 3120531
references.citation: N Engl J Med. 1983 Mar 17;308(11):619-24
references.pmid: 6338383
references.citation: Neurocrit Care. 2005;2(2):110-8
references.pmid: 16159052
references.citation: Comput Med Imaging Graph. 2007 Jun-Jul;31(4-5):285-98
references.pmid: 17376649
references.citation: J Neurosurg. 2004 Aug;101(2):255-61
references.pmid: 15309916
references.citation: Neurology. 2000 Jun 13;54(11):2156-8
references.pmid: 10851383
references.citation: Lancet Neurol. 2003 Jan;2(1):43-53
references.pmid: 12849300
references.citation: Stroke. 2001 Sep;32(9):2012-20
references.pmid: 11546890
references.citation: Psychol Bull. 1979 Mar;86(2):420-8
references.pmid: 18839484
references.citation: Acta Neurochir (Wien). 1982;63(1-4):23-30
references.pmid: 7102415
references.citation: J Neurosurg. 2008 Aug;109(2):199-207
references.pmid: 18671630
references.citation: Neurosurgery. 2012 Oct;71(4):869-75
references.pmid: 22801639
references.citation: Stroke. 1997 Mar;28(3):660-4
references.pmid: 9056628
references.citation: AJR Am J Roentgenol. 1980 Apr;134(4):711-5
references.pmid: 6767356
references.citation: Zentralbl Neurochir. 2003;64(3):104-8
references.pmid: 12975744
references.citation: J Neurol Neurosurg Psychiatry. 1980 Jun;43(6):522-4
references.pmid: 7205294
references.citation: Neuroimage. 2008 Feb 1;39(3):1064-80
references.pmid: 18037310
references.citation: AJNR Am J Neuroradiol. 1994 Jun;15(6):1145-8
references.pmid: 8073985
references.citation: Acta Neurochir (Wien). 1980;55(1-2):63-70
references.pmid: 7211508
references.citation: Neuroimage. 2006 Jul 1;31(3):1116-28
references.pmid: 16545965
references.citation: Neurosurgery. 1980 Jan;6(1):1-9
references.pmid: 7354892