The retroneural approach: an alternative technique for lumbar transforaminal epidural steroid injections.

BACKGROUND: Compared with other available injection techniques for lumbar transforaminal epidural steroid injections (LTFESIs), the traditionally performed subpedicular approach is associated with a higher risk of spinal cord infarction, a rare but catastrophic complication. PURPOSE: To assess the short-term efficacy of the retroneural approach for computed tomography (CT)-guided LTFESIs with respect to different needle-tip positions. MATERIAL AND METHODS: This retrospective analysis included 238 patients receiving 286 CT-guided LTFESIs from January 2013 to January 2016. Short-term outcomes in terms of pain relief were assessed using the visual analogue scale (VAS) at baseline and 30 min after. The needle-tip location was categorized as extraforaminal, junctional, or foraminal relative to the neural foramen. Additionally, the distance from the needle tip to the nerve root was measured. RESULTS: A mean pain reduction of 3.22 points (±2.17 points) on the VAS was achieved. The needle-tip location was extraforaminal in 48% (136/286), junctional in 42% (120/286), and foraminal in 10% (28/286) of the cases. The mean distance from the needle tip to the nerve root was 3.83 mm (±3.37 mm). There was no significant correlation between pain relief and needle-tip position in relation to the neural foramen. Therapy success was not dependent on the distance between the needle tip and the nerve root. No major complications were observed. CONCLUSION: In our population treated with LTFESIs, the retroneural approach was shown to be an effective technique, with no significant differences in pain relief following different needle-tip positions.

Vascular Anatomy Predicts the Risk of Cerebral Ischemia in Patients Randomized to Carotid Stenting Versus Endarterectomy.

BACKGROUND AND PURPOSE: Complex vascular anatomy might increase the risk of procedural stroke during carotid artery stenting (CAS). Randomized controlled trial evidence that vascular anatomy should inform the choice between CAS and carotid endarterectomy (CEA) has been lacking. METHODS: One-hundred eighty-four patients with symptomatic internal carotid artery stenosis who were randomly assigned to CAS or CEA in the ICSS (International Carotid Stenting Study) underwent magnetic resonance (n=126) or computed tomographic angiography (n=58) at baseline and brain magnetic resonance imaging before and after treatment. We investigated the association between aortic arch configuration, angles of supra-aortic arteries, degree, length of stenosis, and plaque ulceration with the presence of ≥1 new ischemic brain lesion on diffusion-weighted magnetic resonance imaging (DWI+) after treatment. RESULTS: Forty-nine of 97 patients in the CAS group (51%) and 14 of 87 in the CEA group (16%) were DWI+ (odds ratio [OR], 6.0; 95% confidence interval [CI], 2.9-12.4; P<0.001). In the CAS group, aortic arch configuration type 2/3 (OR, 2.8; 95% CI, 1.1-7.1; P=0.027) and the degree of the largest internal carotid artery angle (≥60° versus <60°; OR, 4.1; 95% CI, 1.7-10.1; P=0.002) were both associated with DWI+, also after correction for age. No predictors for DWI+ were identified in the CEA group. The DWI+ risk in CAS increased further over CEA if the largest internal carotid artery angle was ≥60° (OR, 11.8; 95% CI, 4.1-34.1) than if it was <60° (OR, 3.4; 95% CI, 1.2-9.8; interaction P=0.035). CONCLUSIONS: Complex configuration of the aortic arch and internal carotid artery tortuosity increase the risk of cerebral ischemia during CAS, but not during CEA. Vascular anatomy should be taken into account when selecting patients for stenting. CLINICAL TRIAL REGISTRATION: URL: http://www.isrctn.com/ISRCTN25337470. Unique identifier: ISRCTN25337470.

Basic Principles and Clinical Applications of Magnetic Resonance Spectroscopy in Neuroradiology.

Magnetic resonance spectroscopy is a powerful tool to assist daily clinical diagnostics. This review is intended to give an overview on basic principles of the technology, discuss some of its technical aspects, and present typical applications in daily clinical routine in neuroradiology.

Is there a role for conventional MRI and MR diffusion-weighted imaging for distinction of skull base chordoma and chondrosarcoma?

BACKGROUND: Chordoma and chondrosarcoma are locally invasive skull base tumors with similar clinical symptoms and anatomic imaging features as reported in the literature. PURPOSE: To determine differentiation of chordoma and chondrosarcoma of the skull base with conventional magnetic resonance imaging (cMRI) and diffusion-weighted MR imaging (DWI) in comparison to histopathological diagnosis. MATERIAL AND METHODS: This retrospective study comprised 96 (chordoma, n = 64; chondrosarcoma, n = 32) patients with skull base tumors referred to the Paul Scherrer Institute (PSI) for proton therapy. cMRI signal intensities of all tumors were investigated. In addition, median apparent diffusion coefficient (ADC) values were measured in a subgroup of 19 patients (chordoma, n = 11; chondrosarcoma, n = 8). RESULTS: The majority 81.2% (26/32) of chondrosarcomas displayed an off-midline growth pattern, 18.8% (6/32) showed clival invasion, 18.8% (6/32) were located more centrally. Only 4.7% (3/64) of chordomas revealed a lateral clival origin. Using cMRI no significant differences in MR signal intensities were observed in contrast to significantly different ADC values (subgroup of 19/96 patients examined by DWI), with the highest mean value of 2017.2 × 10(-6 )mm(2)/s (SD, 139.9( )mm(2)/s) for chondrosarcoma and significantly lower value of 1263.5 × 10(-6 )mm(2)/s (SD, 100.2 × 10(-6 )mm(2)/s) for chordoma (P = 0.001/median test). CONCLUSION: An off-midline growth pattern can differentiate chondrosarcoma from chordoma on cMRI in a majority of patients. Additional DWI is a promising tool for the differentiation of these skull base tumors.

Symptomatic intracranial hemorrhage after stroke thrombolysis: the SEDAN score.

OBJECTIVE: A study was undertaken to develop a score for assessing risk for symptomatic intracranial hemorrhage (sICH) in ischemic stroke patients treated with intravenous (IV) thrombolysis. METHODS: The derivation cohort comprised 974 ischemic stroke patients treated (1995-2008) with IV thrombolysis at the Helsinki University Central Hospital. The predictive value of parameters associated with sICH (European Cooperative Acute Stroke Study II) was evaluated, and we developed our score according to the magnitude of logistic regression coefficients. We calculated absolute risks and likelihood ratios of sICH per increasing score points. The score was validated in 828 patients from 3 Swiss cohorts (Lausanne, Basel, and Geneva). Performance of the score was tested with area under a receiver operating characteristic curve (AUC-ROC). RESULTS: Our SEDAN score (0 to 6 points) comprises baseline blood Sugar (glucose; 8.1-12.0 mmol/l [145-216 mg/dl] = 1; >12.0 mmol/l [>216 mg/dl] = 2), Early infarct signs (yes = 1) and (hyper)Dense cerebral artery sign (yes = 1) on admission computed tomography scan, Age (>75 years = 1), and NIH Stroke Scale on admission (≥10 = 1). Absolute risk for sICH in the derivation cohort was: 1.4%, 2.9%, 8.5%, 12.2%, 21.7%, and 33.3% for 0, 1, 2, 3, 4, and 5 score points, respectively. In the validation cohort, absolute risks were similar (1.0%, 3.5%, 5.1%, 9.2%, 16.9%, and 27.8%, respectively). AUC-ROC was 0.77 (0.71-0.83; p < 0.001). INTERPRETATION: Our SEDAN score reliably assessed risk for sICH in IV thrombolysis-treated patients with anterior- and posterior circulation ischemic stroke, and it can support clinical decision making in high-risk patients. External validation of the score supports its generalization.

Pencil beam scanning proton therapy for the treatment of craniopharyngioma complicated with radiation-induced cerebral vasculopathies: A dosimetric and linear energy transfer (LET) evaluation.

BACKGROUND AND PURPOSE: This study analyses the dosimetric and dose averaged Linear Energy transfer (LETd) correlation in paediatric craniopharyngioma (CP) patients with and without radiation-induced cerebral vasculopathies (RICVs) treated with pencil beam scanning (PBS) proton therapy (PT). MATERIAL AND METHODS: We reviewed a series of 16 CP patients treated with PT to a median dose of 54 Gy(RBE). Two (12.5%) index patients presented RICVs 14 and 24 months (median, 19) after PT. Organs at risks (OARs) as bilateral internal carotid arteries (ICAs) and circle of Willis were contoured based on CTs and MRIs pre- and post-PT. Dosimetry was reviewed and LETd distributions were calculated; LETd metric for PTVs and OARs were analysed. For a sub-cohort, dosimetric and LETd values robustness due to range uncertainties were computed. RESULTS: For the two index patients, no correlation was observed between RICVs and OARs doses. However for those patients mean(maximum) LETd values in the affected OARs were up to 4.0 ± 0.4 (7.8 ± 0.1)keV/µm; those LETd values were significantly higher (p = 0.02) than the mean(maximum) LETd values for the rest of the cohort (mean: 3.1 ± 0.3, maximum: 4.8 ± 1.0 keV/µm). This was due to asymmetric field arrangement, thus resulting in marked asymmetric LETd distributions. For such arrangement, maximum LETd values variations in vascular structures due to range uncertainties were up to 1.2 keV/µm, whilst for the symmetric one they were up to 0.7 keV/µm. CONCLUSIONS: For children with and without RICVs, quantitative analysis showed a significant correlation with LETd average/maximum values in vascular structures, whilst no correlation was found on dosimetric parameters.

Clinical and Radiologic Outcomes in Adults and Children Treated with Pencil-Beam Scanning Proton Therapy for Low-Grade Glioma.

PURPOSE: We assessed clinical and radiologic outcomes in adults and children with low-grade glioma (LGG) of the brain treated with pencil-beam scanning (PBS) proton therapy (PT). MATERIALS AND METHODS: Between 1997 and 2014, 28 patients were treated with PBS PT, 20 (71%) of whom were younger than 18 years. Median age at start of PT was 12.3 years (range, 2.2-53.0 years). Nine patients (32%) underwent at least a subtotal resection; 12 (43%) underwent biopsy; and 7 (25%) were diagnosed radiographically. Twelve patients (43%) had grade II and 9 (32%) had grade I gliomas. Eleven patients (39%) received chemotherapy before PT. A median dose of 54 Gy (relative biologic effectiveness) was administered. Radiologic response to PT was determined using the Response Evaluation Criteria in Solid Tumors (RECIST). Eight domains of quality of life (QoL) for 16 pediatric patients were assessed prospectively by patients' parents using the pediatric QoL proxy questionnaire. Progression-free survival and overall survival (OS) were estimated by the Kaplan-Meier method. Median follow-up was 42.1 months for living patients. RESULTS: Ten patients (36%) developed local, clinical failure. Three patients (11%) died, all of tumor progression. Radiographic tumor response by RECIST was evaluable in 11 patients: 9 (82%) with stable disease, 1 (9%) with partial response, and 1 (9%) with complete response to PT. Three-year OS and progression-free survival were 83.4% and 56.0%, respectively. No ≥ grade III acute toxicities were observed. Grade III, late radiation necrosis developed in 1 patient (4%). No appreciable change in pediatric QoL proxy scores in children was noted in any of the 8 domains at any time point. CONCLUSION: Treatment with PBS PT is effective for LGG, with minimal acute toxicity and, in children, no appreciable decline in QoL. More patients and longer follow-up are needed to determine the long-term efficacy and toxicity of PT for LGG.

Proton Irradiation with Hyperthermia in Unresectable Soft Tissue Sarcoma.

PURPOSE: Unresectable soft tissue sarcomas (STSs) do not usually exhibit significant tumor downstaging with preoperative radiotherapy and/or chemotherapy due to their limited radiosensitivity/chemosensitivity. Limb amputations for tumors of the extremities inevitably lead to considerable loss of function and impairment in quality of life. Local hyperthermia at 39°C to 43°C and proton irradiation combine thermoradiobiological and physical dose distribution advantages, possibly mimicking those of a 12C ion therapy. We report the first 2 patients treated with this unique approach of proton thermoradiotherapy. MATERIALS AND METHODS: Both patients had an unresectable STS of the left lower leg (1 grade 2 myxoid fibrosarcoma, 1 grade 3 undifferentiated pleomorphic sarcoma). Both patients had declined the above-knee amputation that had been advised due to their involvement of the neurovascular bundles. They were, therefore recruited to the Hyperthermia and Proton Therapy in Unresectable Soft Tissue Sarcoma (HYPROSAR) study protocol (ClinicalTrials.gov NCT01904565). Local hyperthermia was delivered using radiofrequency waves at 100 Mhz once a week after proton therapy. Proton irradiation was undertaken to a dose of 70 to 72 Gy (relative biological effectiveness) delivered at 2.0 Gy (relative biological effectiveness)/ fraction daily for 7 weeks. RESULTS: Patients tolerated the treatment well with no significant acute or late morbidity. Both primary tumors showed a near complete response on serial magnetic resonance imaging. At a follow-up of 5 and 14 months, the patients were able to carry out indoor and outdoor activities with normal limb function. CONCLUSION: This is the first report of proton beam irradiation combined with hyperthermia for cancer therapy. Our first experience in 2 consecutive patients with unresectable STSs shows that the approach is safe, feasible, and effective, achieving functional limb preservation with near total tumor control.