Echo-planar imaging for MRI evaluation of intrathoracic tumors in murine models of lung cancer.
OBJECTIVE
To evaluate the efficacy of fast cardiac- and respiratory-gated MRI acquisition methods for noninvasive assessment of tumor volume in murine models of lung cancer.


METHODS
A total of 21 mice bearing either human small-cell (N417) or non-small-cell (H460) lung tumors were scanned using combinations of respiratory-gated computed tomography (CT) imaging, cardiac- and respiratory-gated multishot spin-echo echo-planar imaging (SE-EPI), and cardiac- and respiratory-gated spoiled gradient echo (SPGR). Tumor depiction at 4.7T was qualitatively and quantitatively compared with CT and tissue cross sections. MRI-based measures of tumor volume were compared with ex vivo measurement of tumor mass.


RESULTS
Tumors appeared hyperintense on T(2)-weighted EPI images, providing positive intrinsic contrast between tumors and surrounding tissues. Tumor boundaries were better distinguished by EPI and SPGR with T(1)-reducing contrast enhancement when tumor abutted other tissues than by CT or SPGR without contrast. Tumor volumes measured from EPI images correlate well with ex vivo measurements of tumor mass (P < 0.001, r(2) = 0.99) and volume (P < 0.01, r(2) = 0.98) over a wide range of tumor sizes.


CONCLUSIONS
Respiratory- and cardiac-gated multishot EPI enables accurate, noninvasive assessment of tumor in murine models of lung cancer using a sequence that requires approximately two minutes to complete.
Bankson
James A
JA
Department of Imaging Physics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030-4009, USA. jbankson@mdanderson.org
Ji
Lin
L
Ravoori
Murali
M
Han
Lin
L
Kundra
Vikas
V
D000704:Analysis of Variance; D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D017352:Echo-Planar Imaging / Q000379:methods*; D019786:Gadolinium DTPA; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008175:Lung Neoplasms / Q000473:pathology*; D051379:Mice; D008819:Mice, Nude; D013899:Thoracic Neoplasms / Q000473:pathology*; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D019786:Gadolinium DTPA