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When one uses T2 relaxometry to classify lumbar intervertebral discs as degenerated, it is unclear whether the normative data should be based on other intervertebral discs from the same individual or from a pool of extraneous controls. This study aimed to explore the extent of intra- versus intersubject variation in the T2 times of healthy intervertebral discs.MATERIALS AND METHODS:
Using prospectively acquired T2-relaxometry data from 606 intervertebral discs in 101 volunteers without back pain (47 men, 54 women) in a narrow age range (25–35 years), we calculated intra- and intersubject variation in T2 times of intervertebral discs graded by 2 neuroradiologists on the Pfirrmann scale. Intrasubject variation of intervertebral discs was assessed relative to other healthy intervertebral discs (Pfirrmann grade, ≤2) in the same individual. Multiple intersubject variability measures were calculated using healthy extraneous references ranging from a single randomly selected intervertebral disc to all healthy extraneous intervertebral discs, without and with segmental stratification. These variability measures were compared for healthy and degenerated (Pfirrmann grade ≥3) intervertebral discs.RESULTS:
The mean T2 values of healthy (493/606, 81.3%) and degenerated intervertebral discs were 121.1 ± 22.5 ms and 91.5 ± 18.6 ms, respectively (P < .001). The mean intrasubject variability for healthy intervertebral discs was 9.8 ± 10.7 ms, lower than all intersubject variability measures (P < .001), and provided the most pronounced separation for healthy and degenerated intervertebral discs. Among intersubject variability measures, using all segment-matched healthy discs as references provided the lowest variability (P < .001).CONCLUSIONS:
Normative measures based on the T2 times of healthy intervertebral discs from the same individual are likely to provide the most discriminating means of identifying degenerated intervertebral discs on the basis of T2 relaxometry.
Using the Medicare Physician-Supplier Procedure Summary Master File, we evaluated the evolving use of fMRI in Medicare fee-for-service beneficiaries from 2007 through 2017. Annual use rates (per 1,000,000 enrollees) increased from 17.7 to 32.8 through 2014 and have remained static since. Radiologists have remained the dominant specialty group from 2007 to 2017 (86.4% and 88.6% of all services, respectively), and the outpatient setting has remained the dominant place of service (65.4% and 65.4%, respectively).
In cases of large-vessel-occlusion strokes due to an underlying tandem internal carotid artery occlusion or intracranial atherosclerotic disease, concomitant stent placement may be needed. Immediate platelet inhibition is necessary, but to date, a standardized approach for antiplatelet inhibition in acute settings is still missing. Here we report our single-center experience about the safety and efficacy of periprocedural administration of cangrelor in patients with acute ischemic stroke due to intracranial or cervical artery occlusion undergoing stent placement.MATERIALS AND METHODS:
We retrospectively evaluated all cases of acute ischemic stroke that needed acute stent implantation and were treated with periprocedural administration of cangrelor between January 2019 and April 2020 at our institution. All patients who needed either extracranial or intracranial artery stent placement (in either the anterior or posterior circulation) were included.RESULTS:
We evaluated 38 patients in whom cangrelor was administered IV periprocedurally. Their mean age was 64 years (range, 26–85 years), with 25/38 male subjects and 13/38 female patients. In 26 patients (68.4%), a tandem occlusion was present and was treated with carotid artery stent placement, while 12 patients (31.6%) required an intracranial stent implantation. In 4 subjects (10.5%), an intracerebral hemorrhage occurred after the procedure. All patients in the series were alive 1 week after the procedure.CONCLUSIONS:
Although larger, multicentric randomized studies are strongly warranted, our results support the hypothesis of a possible role of cangrelor as a valuable therapeutic option in the management of platelet inhibition in acute ischemic stroke procedures after intra- or extracranial stent placement.