¹²³I-IMT SPECT and¹HMR-Spectroscopy at 3.0T in the Differential Diagnosis of Recurrent or Residual Gliomas: A Comparative Study

Abstract

The aim of this investigation was to compare two current non-invasive modalities, single photon emission tomography (SPECT) using 123-iodine-alpha-methyl tyrosine (123I-IMT) and single-voxel proton magnetic resonance spectroscopy (1H-MRS) at 3.0 T, with regard to their ability to differentiate between residual/ recurrent tumors and treatment-related changes in patients pretreated for glioma. The patient population comprised 25 patients in whom recurrent glioma was suspected based on MR imaging. SPECT imaging started 10 min after iv. injection of 300-370 MBq 123I-IMT and was performed using a triple-head system. The IMT uptake was calculated semiquantitatively using regions-of-interest. 1H-MRS was performed at 3.0 T using the single-volume point-resolved spectroscopy (PRESS) technique. Guided by MR imaging volumes-of-interest for spectroscopy were placed into the suspected lesions. Signal intensities of choline-containing compounds (Cho), creatine and phosphocreatine (Cr), and N-acetylaspartate (NAA) were obtained. When using the cut-off of 1.62 for 123I-IMT uptake, the sensitivity, specificity, and accuracy of the 123I-IMT SPECT were 95, 100 and 96%, respectively. For 1H-MRS, the sensitivity, specificity and accuracy were 89, 83 and 88%, respectively, based both on the metabolic ratios of Cho/Cr and Cho/NAA as tumor criterion with cut-off values of 1.11 and 1.17, respectively. In conclusion, 123I-IMT SPECT yielded more favorable results compared to 1H-MRS at distinguishing recurrent and/or residual glioma from post-therapeutic changes and may be particularly valuable when the evaluation of tumor extent is necessary.

Metabolic Imaging of Cerebral Gliomas: Spatial Correlation of Changes in O-(2-18F-Fluoroethyl)-l-Tyrosine PET and Proton Magnetic Resonance Spectroscopic Imaging

“…Compared with conventional MRI, they reported an increase in diagnostic accuracy for the combination of MRI with 18 F-FET PET and 1 H MRSI for this purpose. Plotkin et al (42) performed SPECT with 123 I-iodomethyltyrosine and single-voxel MRS for differentiation between residual tumor or recurrence and treatment-related changes in pretreated patients with gliomas (42). They found that 123 I-iodomethyltyrosine had higher sensitivity, specificity, and accuracy than single-voxel MRS for distinguishing the changes.…”

Combined SPECT/CT imaging using 123I-IMT in the detection of recurrent or persistent head and neck cancer

“…IMT-SPECT was proven to be highly useful for the diagnosis of brain tumours by several studies [28][29][30][31][32]. Moreover, the performance of IMT-SPECT was shown to be comparable to PET using MET [20] and the newly introduced tracer O-(2-[ 18 F] fluoroethyl)-L-tyrosine (FET) [33].…”

Letter to the Editor: “The role of imaging in the management of progressive glioblastoma. A systematic review and evidence-based clinical practice guideline” [J Neurooncol 2014; 118:435–460]

“…Moreover, we would like to point out that the excellent results of SPECT with respect to differentiation of tumor recurrence mentioned in the review of Ryken et al is based on the use of the amino acid tracer IMT [16], which delivers similar results as FET PET but at lower spatial resolution [17].…”