Susceptibility weighted imaging for qualitative grading of persistent arteriovenous shunting in deep-seated arteriovenous malformations after stereotactic radiation surgery.

BACKGROUND AND PURPOSE: To investigate Susceptibility Weighted Imaging (SWI) signal changes in the draining vein of deep-seated arterio-venous malformations (AVMs) following stereotactic radiosurgery (SRS). METHODS AND MATERIALS: This is a retrospective study of 32 patients with deep-seated AVMs who were treated with SRS. Pre-SRS treatment and post-SRS treatment MRI were performed at 6, 12, and 24-month intervals. Deep-seated AVMs were classified based on their anatomical location and venous drainage pattern. AVM nidal volume (cm3) was estimated using the ABC/2 method. AV shunting of the AVM draining veins were graded according to its SWI signal intensity: hyperintense (grade III), mixed signal intensity (grade II), hypointense (grade I) and absent (grade 0). Conventional time-of-flight (TOF)-MRA and contrast enhanced (CE)-MRA sequences were performed to document the patency of the vein. RESULTS: Pre-SRS treatment AVM draining veins were either grade III 18/32 (56%) or grade II 14/32 (44%). Using mixed effects analysis, we demonstrate that each month following the SRS treatment nidal volumes decreased at the rate of 0.51 cm3/per month (CI -0.61 to (-0.40)) p =.00. Following the treatment, there was a clinically significant relationship between the signal and nidal volume: signal 0 corresponded with average nidal volume of 1.81 cm3 (CI 1.40-2.21), signal 1 with nidal volume of 2.06 cm3 (CI 1.69-2.44), signal 2 with nidal volume 2.73 cm3 (CI 2.35-3.11) and signal 3 with nidal volume 3.13 cm3 (CI 2.70-3.56) p = .00. CONCLUSION: Post-SRS AVM draining veins shows a stepwise regression of the SWI signal grades which can be reliably used as a surrogate to monitor the reduction of AV shunting.

Functional popliteal artery entrapment syndrome: use of ultrasound guided Botox injection as a non-surgical treatment option.

OBJECTIVE: To determine whether ultrasound-guided injection of botulinum toxin type A (BTX-A) is a viable alternative to surgical intervention for the treatment of functional popliteal artery entrapment syndrome (PAES). MATERIALS AND METHODS: Twenty-seven patients met diagnostic criteria confirming the presence of functional PAES and agreed to go ahead with ultrasound-guided BTX-A injection at the level of artery occlusion. Patients were assessed and treated at baseline and given the option for 'top-up' injections at 6 and 12 months. Patients provided subjective symptom reports at 6 and 12 months post intervention. RESULTS: No patients reported being worse off after the intervention; 59% of patients were categorized as having a good response (i.e., initial improvement that was maintained at 12 months), 22% a mixed response (i.e., an initial improvement that subsequently reduced over 12 months) and 19% a poor response (i.e., no difference) to treatment. CONCLUSIONS: Ultrasound-guided BTX-A injection represents a viable alternative to surgery in the treatment of functional PAES. Further study will help determine the optimum dose and frequency of injection to prevent recurrence of symptoms.