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apparent_diffusion_coefficient

Apparent diffusion coefficient (ADC)

Measures the magnitude of diffusion (of water molecules) within tissue 1).

The ADC value can potentially reveal the differences in cellularity and nuclear atypia of gliomas 2).

Several studies have analyzed a correlation between the apparent diffusion coefficient (ADC) derived from diffusion-weighted MRI and the tumor cellularity of corresponding histopathological specimens in brain tumors with inconclusive findings.

Theoretically, high cellularity in advanced gliomas may impede free water diffusion and thus lead to a decreased ADC value. In a study by Higano et al., the minimum ADC varied significantly between WHO grade III 3).

Another study also revealed a significantly higher frequency of low ADC values in high- compared with low-grade gliomas 4)).

Data confirms a previously reported inverse correlation between ADC and tumor cellularity. However, the correlation in the Eide et al article is weaker than the pooled correlation of comparable previous studies. Hence, besides cell density, other factors, such as necrosis and edema might influence ADC values in glioblastomas 5).

ADC measurements are better than rCBV values for distinguishing the grades of gliomas. The combination of minimum ADC and maximum rCBV improves the diagnostic accuracy of glioma grading 6).

Apparent diffusion coefficient (ADC) values have been shown to assist in differentiating cerebellar pilocytic astrocytomas and medulloblastomas. Previous studies have applied only ADC measurements and calculated the mean/median values.

The abnormality of the FA and ADC parameters in the obstructive hydrocephalus represents a significant implication for the diagnostics and management of hydrocephalus in patients 7).

1)
Sener RN. Diffusion MRI: apparent diffusion coefficient (ADC) values in the normal brain and a classification of brain disorders based on ADC values. Comput Med Imaging Graph. 2001;25 (4): 299-326.
2)
Sadeghi N. et al. Effect of hydrophilic components of the extracellular matrix on quantifiable diffusion-weighted imaging of human gliomas: preliminary results of correlating apparent diffusion coefficient values and hyaluronan expression level. AJR Am J Roentgenol 181, 235–241, 10.2214/ajr.181.1.1810235 (2003
3)
1.06 ± 0.21) × 10−3 mm2/sec) and WHO grade IV gliomas ((0.83 ± 0.14) × 10−3 mm2/sec) ((Higano S. et al. Malignant astrocytic tumors: clinical importance of apparent diffusion coefficient in prediction of grade and prognosis. Radiology 241, 839–846, 10.1148/radiol.2413051276 (2006).
4)
Wen P. Y. & Kesari S. Malignant gliomas in adults. N Engl J Med 359, 492–507, 10.1056/NEJMra0708126 (2008
5)
Eidel O, Neumann JO, Burth S, Kieslich PJ, Jungk C, Sahm F, Kickingereder P, Kiening K, Unterberg A, Wick W, Schlemmer HP, Bendszus M, Radbruch A. Automatic Analysis of Cellularity in Glioblastoma and Correlation with ADC Using Trajectory Analysis and Automatic Nuclei Counting. PLoS One. 2016 Jul 28;11(7):e0160250. doi: 10.1371/journal.pone.0160250. eCollection 2016. PubMed PMID: 27467557.
6)
Hilario A, Ramos A, Perez-Nuñez A, Salvador E, Millan JM, Lagares A, Sepulveda JM, Gonzalez-Leon P, Hernandez-Lain A, Ricoy JR. The added value of apparent diffusion coefficient to cerebral blood volume in the preoperative grading of diffuse gliomas. AJNR Am J Neuroradiol. 2012 Apr;33(4):701-7. doi: 10.3174/ajnr.A2846. Epub 2011 Dec 29. PubMed PMID: 22207304.
7)
Shevtsov MA, Senkevich KA, Kim AV, Gerasimova KA, Trofimova TN, Kataeva GV, Medvedev SV, Smirnova OI, Savintseva ZI, Martynova MG, Bystrova OA, Pitkin E, Yukina GY, Khachatryan WA. Changes of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in the model of experimental acute hydrocephalus in rabbits. Acta Neurochir (Wien). 2015 Jan 16. [Epub ahead of print] PubMed PMID: 25591802.
apparent_diffusion_coefficient.txt · Last modified: 2016/07/29 20:22 (external edit)