title: Radiation necrosis vs high-grade recurrent glioma: differentiation by using dual-isotope SPECT with 201TI and 99mTc-HMPAO.
abstract: Conventional imaging techniques are often unreliable in distinguishing between radiation necrosis and recurrent glioma in patients who are symptomatic after high-dose radiotherapy. We performed dual-isotope single-photon emission computed tomography (SPECT) with the use of thallium-201 (201TI) and the perfusion agent 99mTc-hexamethyl-propyleneamine oxime (HMPAO) to aid in this differentiation in 15 patients with glioma prior to biopsy. We found that dual-isotope SPECT scanning correlated with the pathologic findings in 14 of the 15 cases. All patients with high 201TI uptake in their treated tumor beds had local tumor recurrence, and all patients with low 201TI uptake showed only radiation changes without evidence of solid tumor. In patients with an intermediate level of 201TI concentration in their tumor bed, 99mTc-HMPAO uptake differentiated those patients with active tumor from those without; three of four patients with preserved or increased perfusion had pathologic evidence of solid tumor, whereas none of the four patients with decreased perfusion to the tumor bed had evidence of local recurrence. We believe that dual-isotope SPECT with 201TI and 99mTc-HMPAO may be useful in differentiating sites of likely tumor growth from nonspecific radiation changes in patients treated for malignant glioma.
authors.affiliation: Department of Radiology, Harvard Medical School, Boston, MA.
authors.forename: R B
authors.initials: RB
authors.lastname: Schwartz
authors.forename: P A
authors.initials: PA
authors.lastname: Carvalho
authors.forename: E
authors.initials: E
authors.lastname: Alexander
authors.forename: J S
authors.initials: JS
authors.lastname: Loeffler
authors.forename: R
authors.initials: R
authors.lastname: Folkerth
authors.forename: B L
authors.initials: BL
authors.lastname: Holman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D002648:Child; D003937:Diagnosis, Differential; D005910:Glioma / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D008875:Middle Aged; D009336:Necrosis; D015609:Organotechnetium Compounds; D010091:Oximes; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D019690:Technetium Tc 99m Exametazime; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014057:Tomography, X-Ray Computed
chemical_list: D015609:Organotechnetium Compounds; D010091:Oximes; D013794:Thallium Radioisotopes; D019690:Technetium Tc 99m Exametazime