Detection of intratumoral calcification in oligodendrogliomas by susceptibility-weighted MR imaging

Abstract

Background and purpose: SWI is a unique pulse sequence sensitive to both hemorrhage and calcification. Our aim was to retrospectively assess the ability of SWI to detect intratumoral calcification in ODs compared with conventional MR imaging.

Materials and methods: Using CT as criterion standard, the MR imaging findings from 71 patients (33 males, 38 females; mean age, 42.5 years) with pathologically proved OD were retrospectively evaluated. We classified the MR imaging data into SWI data (MRSWI) and traditional pulse sequences (MRnoSWI). The sensitivity and specificity of the MRnoSWI (n = 71) were compared with that of the MRSWI (n = 13) independently and also for matched-paired data (n = 13). The Fisher exact test was applied to the matched-pair data for statistical evaluation.

Results: For paired data of MRSWI and MRnoSWI (n = 13), there was significantly increased sensitivity of MRSWI (86%) for the detection of intratumoral calcification in OD compared with the MRnoSWI (14.3%) (P = .015, Fisher exact test) by using CT as the criterion standard. The overall accuracy of MRSWI for the paired data was also significantly greater (P = .048). The specificities were not significantly different (P = .773). The sensitivity of MRSWI (n = 13) was 86%, and for MRnoSWI (n = 71), it was 33.3%. Specificity of MRSWI was 83%, and for MRnoSWI, it was 95%.

Conclusions: SWI is better able to detect calcification in ODs than conventional MR imaging pulse sequences.

Fig 1.

Imaging findings of a 23-year-old woman with a histopathologic diagnosis of OD. A, CT shows a 2.3 × 3.3 cm ill-defined relatively hypoattenuated mass in the left frontal lobe with curvilinear calcification (arrow). There is no hemorrhage. B, T2WI image shows an intermediate-to-hyperintense lesion. The area of calcification by CT is seen on the MR imaging study, but it is hypointense and, therefore, is not suggestive of calcification (arrow). C, SWI image shows curvilinear calcification (hypointense area). D, SWI mIP image shows calcification.

Fig 2.

Value of phase imaging in identifying calcification in OD. Magnitude (A), mIP (B), and SWI (C) images do not help distinguish iron-containing hemorrhage from calcification in this tumor. D, Phase image shows high signal intensity centrally identifying calcification. E, CT image shows faint hyperattenuation, which had persisted for months and represented calcified tumor.

Fig 3.

Calcification on SWI series. Again, the magnitude (A), mIP (B), and SWI (C) images could represent hemorrhage or calcification. D and E, However, the phase image (D) shows hyperintensity of calcification, confirmed on the CT scan (E).

Fig 4.

Postoperative OD with hemorrhage and calcification. Magnitude (A), mIP (B), and SWI (C) images fail to distinguish hemorrhage in the operative bed from calcification. D and E, Phase images show mixed signal intensity, but an area of high signal intensity more medially (arrow) was read as representing calcification. CT confirmed a calcified component (arrow).