Artikel
Spinal diffusion tensor imaging in intramedullary tumors – tumor entity, differentiation of inflammatory lesions and operation planning
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Veröffentlicht: | 8. Juni 2016 |
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Gliederung
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Objective: Magnetic resonance imaging (MRI) is commonly applied for spinal tumor imaging because of its superior lesion perceptibility and local resolution. The differentiation of the specific tumor entities and furthermore the discrimination of inflammatory lesions is challenging and can lead to unnecessary operative therapies. The spinal diffusion tensor imaging (DTI) can provide additional information concerning the primary diagnosis and location of the spinal fiber tracts in relation to the pathology. Image quality can be enhanced by using a multi-shot echo-planar DTI in comparison to single-shot DTI technics with their severe artefacts caused by the surrounding bone tissue. Aim of this study was to evaluate the multi-shot DTI for primary entity diagnosis of intramedullary tumor lesions and discrimination of inflammatory lesions based on visualized fiber tracts.
Method: In our prospective study, we examined 23 patients with a suspected intramedullary tumor in standard MRI work-up with an additional multi-shot echo-planar (RESOLVE) DTI and resulting tractography. Two radiologists evaluated the reconstructed images blinded for the final diagnosis by using a simple, new developed scale for the fiber tract morphology (1- normal appearing fiber tracts; 2- translocated fiber tracts, 3- interrupted fiber tracts). Final diagnoses were determined by histology or in conservatively treated inflammatory cases, by neurologic diagnostic work-up.
Results: All acute inflammatory lesions showed an unremarkable DTI with normal fiber tracts. Three of the four ependymomas and one cervical cyst showed translocated fibers. The fourth ependymoma showed interrupted tracts caused by a local hemorrhage. The pilocytic astrocytomas were dislocating too, whereas the higher grade astrocytomas showed an interruption of the tracts. The DTI images used for surgical planning showed a 100% positive feedback from the surgeon.
Conclusions: Intramedullary tumors and inflammatory lesions can, due to their different underlying pathological mechanisms, reliably differentiated by our multi-shot DTI imaging. The benign tumors (ependymomas and pilocytic astrocytomas) showed translocated fibers because of their slow displacing development. Higher grade astrocytomas predominantly lead to interrupted spinal fiber tracts due to an invasive growth. So spinal multi-shot DTI sequences can provide valuable diagnostic information about spinal processes and therefore affect the further treatment for those patients.