Spectroscopy imaging in intraoperative MR suite: tissue characterization and optimization of tumor resection.

BACKGROUND: MR spectroscopy (MRS) measurements are common practice in the preoperative diagnostic regimen, but no evidence exists concerning their value in intraoperative MRI (iMRI) setting. We sought to examine the feasibility of intraoperative MRS and to assess the clinical value of the method in optimizing the gliomas resection. METHODS: Forty-five patients with low- and high-grade gliomas underwent iMRI-assisted surgery, including pre- and intraoperative MRS measurements. During the intraoperative control scan, MRS was performed at the resection margin. Peak areas under the major metabolites (N-acetyl-aspartate: NAA; choline: Cho; and creatine: Cr) resonances were estimated, and their ratios entered in the statistical analysis. RESULTS: Concerning preoperative MRS imaging, mean Cho/NAA and Cho/Cr ratios in low-grade gliomas were 2.3 and 1.2, respectively. The average Cho/NAA and Cho/Cr ratios in the high-grade gliomas were 3.9 and 2.3, respectively. In 12 out of 20 cases with low-grade gliomas, intraoperative conventional MR imaging showed suspected tumor remnant and MRS diagnosed correctly the tissue signal alterations in 10 out of those 12 cases. MRS could characterize gadolinium-enhancing or non-enhancing tumor remnants in all cases with high-grade tumors. Thus, it could help achieve total tumor resection unless the latter was contraindicated due to increased risk of neurological complications. CONCLUSIONS: MR spectroscopy (MRS) in an iMRI setting is feasible, facilitating preoperative glioma staging as well as satisfactory characterization of suspected tumor remnants. Thus, it may be helpful tool for an extended tumor resection.

Safe resection of arteriovenous malformations in eloquent motor areas aided by functional imaging and intraoperative monitoring.

BACKGROUND: Arteriovenous malformations (AVMs) proximal to motor cortical areas or motor projection systems are challenging to manage because of the risk of severe sensory and motor impairment. Surgical indication in these cases therefore remains controversial. OBJECTIVE: To propose a standardized approach for centrally situated AVMs based on functional imaging and intraoperative electrophysiological evaluation. METHODS: We conducted a retrospective analysis of 15 patients who underwent surgical treatment for AVMs in motor cortical areas or proximal to motor projections. Preoperative assessment included functional magnetic resonance and 3-dimensional tractography. Operations were performed under continuous electrophysiological monitoring aided by direct brain stimulation. We identified critical bloody supply to the motor areas by temporary occluding the feeding vessels under electrophysiological monitoring. Clinical outcome was evaluated with the modified Rankin Scale. RESULTS: Total resection was achieved in 12 cases, whereas electrophysiology limited total extirpation in 3 cases. A significant reduction of motor evoked potentials by up to 15% of the initial values was associated with good recovery of motor function; in contrast, the disappearance of potentials correlated with long-term impairment. The mean follow-up time was 13 months, and clinical assessments revealed overall functional improvement (P < .05). After surgery, 11 patients were asymptomatic or presented with only minor neurological deficits. CONCLUSION: Surgical resection of AVMs in eloquent motor areas can be considered a safe option for selected cases when performed in conjunction with a detailed functional assessment. Possible selection criteria for surgical treatment are discussed in light of the presented clinical data.

Spinal metastasis of endometrial stromal sarcoma: clinicopathological features and management.

BACKGROUND: Endometrial Stromal Sarcoma (ESS) is a rare uterine malignancy which often metastasizes several years after initial diagnosis. Thoracic spine is a rare ESS metastatic site and its proper management is still not a consensus. We discuss the histopathological features and the management strategies through an illustrative case of a 77 year-old woman with metastasis to the thoracic spine 13 years after total hysterectomy for ESS. METHODS: Review of the literature and identification of 5 patients, including our present case, with ESS involving the spinal cord. We discuss the outcomes achieved after each therapy. In our case, the patient presented a mass involving the thoracic spinal canal constricting the spinal cord at T7 level. A two-level decompression laminectomy was performed and the lesion was partially excised. RESULTS: The histopathological along with the immunohistochemical profile mitotic rate indicated the endometrial stromal cells origin of the tumor, confirming the diagnosis of a low-grade ESS metastasis. The patient was managed with surgery in combination with postoperative radiation therapy. CONCLUSIONS: The small number of published cases precludes definitive conclusions regarding standard management. However, it seems that treatment of metastatic ESS to the spine matches the same general concepts of spine metastasis, namely surgery followed by radiation therapy, due to clinical improvement and long-term disease control of the reported cases. Hormonal therapy may be considered in recurrent disease with strong expression of estrogen and progesterone receptors. However, these findings need confirmation in larger studies.