Intracranial Calcifications and Hemorrhages: Characterization with Quantitative Susceptibility Mapping

Abstract

Purpose:To compare gradient-echo (GRE) phase magnetic resonance (MR) imaging and quantitative susceptibility mapping (QSM) in the detection of intracranial calcifications and hemorrhages. Materials and Methods:This retrospective study was approved by the institutional review board. Results:A total of 156 lesions were detected: 62 hemorrhages, 89 calcifications, and five mixed lesions containing both hemorrhage and calcification. Most of these lesions (146 of 151 lesions, 96.7%) had a dominant sign on QSM images suggestive of a specific diagnosis of hemorrhage or calcium, whereas half of these lesions (76 of 151, 50.3%) were heterogeneous on GRE phase images and thus were difficult to characterize. Averaged over the two independent observers for detecting hemorrhages, QSM achieved a sensitivity of 89.5% and a specificity of 94.5%, which were significantly higher than those at GRE phase imaging (71% and 80%, respectively; P , .05 for both readers). In the identification of calcifications, QSM achieved a sensitivity of 80.5%, which was marginally higher than that with GRE phase imaging (71%; P = .08 and .10 for the two readers), and a specificity of 93.5%, which was significantly higher than that with GRE phase imaging (76.5%; P , .05 for both readers). QSM achieved significantly better interobserver agreements than GRE phase imaging in the differentiation of hemorrhage from calcification (k: 0.91 vs 0.55, respectively; P , .05). Conclusion:QSM is superior to GRE phase imaging in the differentiation of intracranial calcifications from hemorrhages and with regard to the sensitivity and specificity of detecting hemorrhages and the specificity of detecting calcifications.q RSNA, 2013

Imaging Cardiovascular Calcification

“…However, vascular calcification is diamagnetic and with only a few protons present, visualization is poor with conventional MRI sequences 71, 72. In past decades, there has been considerable progress in MR scanning technology and parameters, including the development of multicontrast MR protocols 73, 74, 75.…”

Diagnostic performance of susceptibility-weighted magnetic resonance imaging for the assessment of sub-coracoacromial spurs causing subacromial impingement syndrome

“…Due to phase artefacts, it has been challenging in the past to routinely extract this information. The development of SWMR has made it feasible to reliably detect calcific lesions in MRI due to their diamagnetic properties [13][14][15][16][17][18][19][20][21][22]. SWMR is based on the development of novel filtering techniques and enables the extraction of this information, which can be used for further characterization of tissues [13,14].…”

“…d. SWMR shows a corresponding signal hyperintensity in the inverse magnitude SW image e. Corrected SW phase image does not show any corresponding signal hyperintensity (arrows), confirming the absence of sub-coracoacromial spur formation phase images. Based on these principles, SWMR enables the differentiation of focal calcifications or bony lesions from other sources of susceptibility differences in tissues [14,15,19,20]. …”

“…SWMR is based on the development of novel filtering techniques and enables the extraction of phase information, which can be used for further characterization of tissues [13,14]. Using the combination of magnitude and phase information, SWMR has made it feasible to detect calcific lesions in MRI due to their diamagnetic properties [13][14][15][16][17][18][19][20][21][22]. Different studies demonstrated the potential of SWMR for the characterization of neurological disorders or brain tumours and the differentiation of diamagnetic calcifications from paramagnetic intratumoral haemorrhage [15,21].…”

The History of MR Imaging as Seen through the Pages ofRadiology

“…With quantitative susceptibility mapping, one can estimate the iron content of hemorrhagic lesions. In contrast to susceptibility-weighted imaging, quantitative susceptibility mapping allows the diamagnetic susceptibility of calcifications to be readily distinguished from the paramagnetic susceptibility of iron-containing lesions (138).…”