title: Dynamic contrast-enhanced magnetic resonance imaging of osseous spine metastasis before and 1 hour after high-dose image-guided radiation therapy.
abstract: OBJECTIVE High-dose image-guided radiation therapy (HD IGRT) has been instrumental in mitigating some limitations of conventional RT. The recent emergence of dynamic contrast-enhanced (DCE) MRI to investigate tumor physiology can be used to verify the response of human tumors to HD IGRT. The purpose of this study was to evaluate the near-immediate effects of HD IGRT on spine metastases through the use of DCE MRI perfusion studies. METHODS Six patients with spine metastases from prostate, thyroid, and renal cell carcinoma who underwent HD IGRT were studied using DCE MRI prior to and 1 hour after HD IGRT. The DCE perfusion parameters plasma volume (Vp) and vascular permeability (Ktrans) were measured to assess the near-immediate and long-term tumor response. A Mann-Whitney U-test was performed to compare significant changes (at p ≤ 0.05) in perfusion parameters before and after RT. RESULTS The authors observed a precipitous drop in Vpwithin 1 hour of HD IGRT, with a mean decrease of 65.2%. A significant difference was found between Vpvalues for before and 1 hour after RT (p ≤ 0.05). No significant change was seen in Vp(p = 0.31) and Ktrans(p = 0.1) from 1 hour after RT to the first follow-up. CONCLUSIONS The data suggest that there is an immediate effect of HD IGRT on the vascularity of spine metastases, as demonstrated by a precipitous decrease in Vp. The DCE MRI studies can detect such changes within 1 hour after RT, and findings are concordant with existing animal models.
authors.affiliation: Departments of1Radiology.
authors.forename: Eric
authors.initials: E
authors.lastname: Lis
authors.affiliation: Departments of1Radiology.
authors.forename: Atin
authors.initials: A
authors.lastname: Saha
authors.affiliation: Departments of1Radiology.|2Medical Physics.
authors.forename: Kyung K
authors.initials: KK
authors.lastname: Peck
authors.affiliation: 3Radiation Oncology, and.
authors.forename: Joan
authors.initials: J
authors.lastname: Zatcky
authors.affiliation: 3Radiation Oncology, and.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Zelefsky
authors.affiliation: 3Radiation Oncology, and.
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: 2Medical Physics.
authors.forename: Andrei I
authors.initials: AI
authors.lastname: Holodny
authors.affiliation: 4Neurosurgery, Memorial Sloan Kettering Cancer Center, New York, New York.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Bilsky
authors.affiliation: Departments of1Radiology.
authors.forename: Sasan
authors.initials: S
authors.lastname: Karimi
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000473:pathology; D002292:Carcinoma, Renal Cell / Q000473:pathology; D003287:Contrast Media / Q000493:pharmacokinetics; D005500:Follow-Up Studies; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000473:pathology; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy* / Q000556:secondary; D013964:Thyroid Neoplasms / Q000473:pathology
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: AIF = arterial input function; ASMase = acid sphingomyelinase; DCE = dynamic contrast-enhanced; FA = flip angle; FOV = field of view; HD IGRT = high-dose image-guided radiation therapy; Ktrans = vascular permeability; ROI = region of interest; Vp = plasma volume; dynamic contrast-enhanced MRI; high-dose image-guided radiation therapy; spine tumor response