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Gautam Nayar, Daniel J. Blizzard, Timothy Y. Wang, Steven Cook, Adam G. Back, David Vincent and Isaac O. Karikari

OBJECTIVE

A previous study found that ultra-low radiation imaging (ULRI) with image enhancement significantly decreases radiation exposure by roughly 75% for both the patient and operating room personnel during minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) (p < 0.001). However, no clinical data exist on whether this imaging modality negatively impacts patient outcomes. Thus, the goal of this randomized controlled trial was to assess pedicle screw placement accuracy with ULRI with image enhancement compared with conventional, standard-dose fluoroscopy for patients undergoing single-level MIS-TLIF.

METHODS

An institutional review board–approved, prospective internally randomized controlled trial was performed to compare breach rates for pedicle screw placement performed using ULRI with image enhancement versus conventional fluoroscopy. For cannulation and pedicle screw placement, surgery on 1 side (left vs right) was randomly assigned to be performed under ULRI. Screws on the opposite side were placed under conventional fluoroscopy, thereby allowing each patient to serve as his/her own control. In addition to standard intraoperative images to check screw placement, each patient underwent postoperative CT. Three experienced neurosurgeons independently analyzed the images and were blinded as to which imaging modality was used to assist with each screw placement. Screw placement was analyzed for pedicle breach (lateral vs medial and Grade 0 [< 2.0 mm], Grade 1 [2.0–4.0 mm], or Grade 2 [> 4.0 mm]), appropriate screw depth (50%–75% of the vertebral body’s anteroposterior dimension), and appropriate screw angle (within 10° of the pedicle angle). The effective breach rate was calculated as the percentage of screws evaluated as breached > 2.0 mm medially or postoperatively symptomatic.

RESULTS

Twenty-three consecutive patients underwent single-level MIS-TLIF, and their sides were randomly assigned to receive ULRI. No patient had immediate postoperative complications (e.g., neurological decline, need for hardware repositioning). On CT confirmation, 4 screws that had K-wire placement and cannulation under ULRI and screw placement under conventional fluoroscopy showed deviations. There were 2 breaches that deviated medially but both were Grade 0 (< 2.0 mm). Similarly, 2 breaches occurred that were Grade 1 (> 2.0 mm) but both deviated laterally. Therefore, the effective breach rate (breach > 2.0 mm deviated medially) was unchanged in both imaging groups (0% using either ULRI or conventional fluoroscopy; p = 1.00).

CONCLUSIONS

ULRI with image enhancement does not compromise accuracy during pedicle screw placement compared with conventional fluoroscopy while it significantly decreases radiation exposure to both the patient and operating room personnel.

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Timothy H. Ung, Christopher Kellner, Justin A. Neira, Shih-Hsiu J. Wang, Randy D’Amico, Phyllis L. Faust, Peter Canoll, Neil A. Feldstein and Jeffrey N. Bruce

Intravenous administration of fluorescein sodium fluoresces glioma burden tissue and can be visualized using the surgical microscope with a specialized filter. Intraoperative guidance afforded through the use of fluorescein may enhance the fidelity of tissue sampling, and increase the ability to accomplish complete resection of tectal lesions. In this report the authors present the case of a 19-year-old man with a tectal anaplastic pilocytic astrocytoma in which the use of fluorescein sodium and a Zeiss Pentero surgical microscope equipped with a yellow 560 filter enabled safe complete resection. In conjunction with neurosurgical navigation, added intraoperative guidance provided by fluorescein may be beneficial in the resection of brainstem gliomas.

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Randy S. D'Amico, George Zanazzi, Gunnar Hargus, Timothy Dyster, Shirley Chan, Angela Lignelli-Dipple, Tony J. C. Wang, Phyllis L. Faust and Guy M. McKhann II

Tufted angioma (TA) is a rare, slow-growing, vascular lesion that commonly presents as a solitary macule, papule, or nodule arising in the soft tissues of the torso, extremities, and head and neck in children and young adults. Adult-onset cases have been infrequently reported. While typically benign, TAs may be locally aggressive. Complete physical examination and hematological workup are recommended in patients with TA to exclude the presence of Kasabach-Merritt phenomenon (KMP). The authors describe the case of a 69-year-old man with a contrast-enhancing frontal lobe lesion, with surrounding vasogenic edema, which was treated by gross-total resection. Characteristic histological features of a TA were demonstrated, with multiple cannonball-like tufts of densely packed capillaries emanating from intraparenchymal vessels in cerebral cortex and adjacent white matter. Tumor recurrence was detected after 4 months and treated with adjuvant Gamma Knife radiosurgery. To the extent of the authors' knowledge, this case illustrates the first report of TA presenting in an adult as an intracranial intraaxial tumor without associated KMP. The fairly rapid regrowth of this tumor, requiring adjuvant treatment after resection, is consistent with a potential for locally aggressive growth in a TA occurring in the brain.

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Yuhao Huang, Timothy G. Singer, Michael Iv, Bryan Lanzman, Siddharth Nair, James A. Stadler III, Jia Wang, Michael S. B. Edwards, Gerald A. Grant, Samuel H. Cheshier and Kristen W. Yeom

OBJECTIVE

Children with intracranial arteriovenous malformations (AVMs) undergo digital DSA for lesion surveillance following their initial diagnosis. However, DSA carries risks of radiation exposure, particularly for the growing pediatric brain and over lifetime. The authors evaluated whether MRI enhanced with a blood pool ferumoxytol (Fe) contrast agent (Fe-MRI) can be used for surveillance of residual or recurrent AVMs.

METHODS

A retrospective cohort was assembled of children with an established AVM diagnosis who underwent surveillance by both DSA and 3-T Fe-MRI from 2014 to 2016. Two neuroradiologists blinded to the DSA results independently assessed Fe-enhanced T1-weighted spoiled gradient recalled acquisition in steady state (Fe-SPGR) scans and, if available, arterial spin labeling (ASL) perfusion scans for residual or recurrent AVMs. Diagnostic confidence was examined using a Likert scale. Sensitivity, specificity, and intermodality reliability were determined using DSA studies as the gold standard. Radiation exposure related to DSA was calculated as total dose area product (TDAP) and effective dose.

RESULTS

Fifteen patients were included in this study (mean age 10 years, range 3–15 years). The mean time between the first surveillance DSA and Fe-MRI studies was 17 days (SD 47). Intermodality agreement was excellent between Fe-SPGR and DSA (κ = 1.00) but poor between ASL and DSA (κ = 0.53; 95% CI 0.18–0.89). The sensitivity and specificity for detecting residual AVMs using Fe-SPGR were 100% and 100%, and using ASL they were 72% and 100%, respectively. Radiologists reported overall high diagnostic confidence using Fe-SPGR. On average, patients received two surveillance DSA studies over the study period, which on average equated to a TDAP of 117.2 Gy×cm2 (95% CI 77.2–157.4 Gy×cm2) and an effective dose of 7.8 mSv (95% CI 4.4–8.8 mSv).

CONCLUSIONS

Fe-MRI performed similarly to DSA for the surveillance of residual AVMs. Future multicenter studies could further investigate the efficacy of Fe-MRI as a noninvasive alternative to DSA for monitoring AVMs in children.