MRI of retinal and choroidal blood flow with laminar resolution.
The retina is nourished by two distinct circulations: the retinal vessels within the inner retina and the choroidal vessels behind the neural retina. The outer nuclear layer and the inner and outer segments of the photoreceptors in between are avascular. The aim of this study was to determine whether arterial spin labeling MRI could provide sufficient resolution to differentiate between quantitative retinal blood flow (rBF) and choroidal blood flow (chBF), and whether this technique is sufficiently sensitive to detect vascular-specific blood flow (BF) changes modulated by anesthetics. Arterial spin labeling MRI was performed at 42 × 42 × 400 µm(3) in the mouse retina at 7 T, and was used to investigate the effects of isoflurane and ketamine/xylazine anesthesia on rBF and chBF. MRI yielded unambiguous differentiation of rBF, chBF and the avascular layer in between. Under isoflurane, chBF was 7.7 ± 2.1 mL/g/min and rBF was 1.3 ± 0.44 mL/g/min (mean ± SD, n = 7, p < 0.01). Under ketamine/xylazine anesthesia in the same animals, chBF was 4.3 ± 1.9 mL/g/min and rBF was 0.88 ± 0.22 mL/g/min (p < 0.01). Under ketamine/xylazine anesthesia, rBF was lower by 29% (P < 0.01) and chBF by 42% (P < 0.01) relative to isoflurane. This study demonstrates, for the first time, the quantitative imaging of rBF and chBF in vivo, providing a new method to study basal values and alterations of rBF and chBF.
Muir
Eric R
ER
Research Imaging Center, Departments of Ophthalmology, Radiology and Physiology, University of Texas Health Science Center, San Antonio, TX 78229, USA.
Duong
Timothy Q
TQ
D000818:Animals; D002829:Choroid / Q000098:blood supply*; D005260:Female; D007530:Isoflurane; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012039:Regional Blood Flow / Q000502:physiology*; D012160:Retina / Q000502:physiology*
D007530:Isoflurane
Exp Eye Res. 1988 Mar;46(3):289-303
3350072
Invest Ophthalmol Vis Sci. 1987 Aug;28(8):1281-9
3610546
Invest Ophthalmol Vis Sci. 2000 Nov;41(12):3999-4006
11053305
Invest Ophthalmol Vis Sci. 1980 Nov;19(11):1355-9
7429770
Opt Express. 2009 Jun 22;17(13):10584-98
19550454
Invest Ophthalmol Vis Sci. 1994 May;35(6):2857-64
8188481
Am J Ophthalmol. 2008 Oct;146(4):496-500
18639219
Exp Eye Res. 2007 Jan;84(1):108-17
17069799
Brain Res. 2001 Sep 21;913(2):174-9
11549383
Anat Rec. 1966 Dec;156(4):383-95
4960396
Exp Eye Res. 2008 Jun;86(6):908-13
18420196
Anesthesiology. 1999 Sep;91(3):677-80
10485778
Invest Ophthalmol. 1964 Oct;3:539-47
14229941
Vision Res. 2004;44(16):1857-67
15145680
Invest Ophthalmol Vis Sci. 1994 Dec;35(13):4273-81
8002247
Anesthesiology. 1992 Mar;76(3):455-60
1539858
Invest Ophthalmol Vis Sci. 1988 Jun;29(6):861-8
3372163
J Cereb Blood Flow Metab. 1985 Mar;5(1):65-9
3871783
Proc Natl Acad Sci U S A. 2006 Nov 14;103(46):17525-30
17088544
Invest Ophthalmol Vis Sci. 1999 Mar;40(3):689-96
10067972
Can J Ophthalmol. 2008 Jun;43(3):295-301
18443612
Exp Eye Res. 1977 Jul;25(1):19-24
408161
Ann Biomed Eng. 2007 Apr;35(4):615-30
17277991
Can Vet J. 2003 Nov;44(11):885-97
14664351
Invest Ophthalmol Vis Sci. 1987 Apr;28(4):672-5
3557871
Magn Reson Med. 2008 Sep;60(3):744-8
18727091
Opt Express. 2008 Jul 7;16(14):10214-9
18607429
Invest Ophthalmol Vis Sci. 1999 Nov;40(12):2925-31
10549654
Magn Reson Med. 2008 Apr;59(4):731-8
18383302
Graefes Arch Clin Exp Ophthalmol. 1983;221(3):110-2
6689414
Jpn J Ophthalmol. 2009 Jul;53(4):352-67
19763752
Am J Physiol. 1991 Sep;261(3 Pt 2):H960-8
1887939
Exp Eye Res. 1988 Nov;47(5):669-78
3197768
Exp Eye Res. 2009 Dec;89(6):960-6
19698709
Neuroimage. 2008 Feb 15;39(4):1744-51
18063388
Am J Physiol Regul Integr Comp Physiol. 2000 Jul;279(1):R202-9
10896883
J Magn Reson Imaging. 2006 Apr;23(4):465-72
16523482
Invest Ophthalmol Vis Sci. 1994 Mar;35(3):981-90
8125761
Invest Ophthalmol Vis Sci. 2001 Apr;42(5):1038-44
11274083
Invest Ophthalmol Vis Sci. 2009 Apr;50(4):1824-30
18952917
Invest Ophthalmol Vis Sci. 2006 Jun;47(6):2668-74
16723485
J Cereb Blood Flow Metab. 2003 Apr;23(4):472-81
12679724
J Ocul Pharmacol. 1992 Fall;8(3):183-90
1453082
Microvasc Res. 2001 Sep;62(2):143-53
11516243