Diehn, Felix E.

Standard clinical protocols require hearing protection during magnetic resonance imaging (MRI) for patient safety. This investigation prospectively evaluated the auditory function impact of acoustic noise exposure during a 3.0T MRI in healthy adults. Twenty-nine participants with normal hearing underwent a comprehensive audiologic assessment before and immediately following a clinically indicated head MRI. Appropriate hearing protection with earplugs (and pads) was used per standard of practice. To characterize noise hazards, current sound monitoring tools were used to measure levels of pulse sequences measured. A third audiologic test was performed if a significant threshold shift (STS) was identified at the second test, within 30 days post MRI. Some sequences produced high levels (up to 114.5 dBA; 129 dB peak SPL) that required hearing protection but did not exceed 100% daily noise dose. One participant exhibited an STS in the frequency region most highly associated with noise-induced hearing loss. No participants experienced OSHA-defined STS in either ear. Overall, OAE measures did not show evidence of changes in cochlear function after MRI. In conclusion, hearing threshold shifts associated with hearing loss or OAE level shifts reflecting underlying cochlear damage were not detected in any of the 3.0T MRI study participants who used the current recommended hearing protection.

AbstractPurposeTo demonstrate the feasibility of simultaneous dual‐contrast imaging in a large animal using a newly developed dual‐source energy‐integrating detector (EID)‐based multi‐energy computed tomography (MECT) system.MethodsTwo imaging tasks that may have potential clinical applications were investigated: head/neck (HN) CT angiography (CTA)/CT venography (CTV) with iodine and gadolinium, and small bowel imaging with iodine and bismuth in domestic swine. Dual‐source X‐ray beam configurations of 70 kV + Au120/Sn120 kV and 70 kV + Au140/Sn140 kV were used for the HN‐CTA/CTV and small bowel imaging studies, respectively. A test bolus scan was performed for each study. The regions of interest (ROIs) in the carotid artery and jugular vein for HN‐CTA/CTV imaging and abdominal aorta for small bowel imaging were used to determine the time‐attenuation curves, based on which the timing for contrast injection and the CT scan was determined. In the HN‐CTA/CTV study, an MECT scan was performed at the time point corresponding to the optimal arterial enhancement by iodine and the optimal venous enhancement by gadolinium. In the small bowel imaging study, an MECT scan was performed at the optimal time point to simultaneously capture the mesenteric arterial enhancement of iodine and the enteric enhancement of bismuth. Image‐based material decomposition was performed to decompose different materials for each study. To quantitatively characterize contrast material separation and misclassification, two ROIs on left common carotid artery and left internal jugular vein in HN‐CTA/CTV imaging and three ROIs on superior mesenteric artery, ileal lumen, and collapsed ileum (ileal wall) in small bowel imaging were placed to measure the mean concentration values and the standard deviations.ResultsIn the HN‐CTA/CTV study, common carotid arteries containing iodine and internal/external jugular veins containing gadolinium were clearly delineated from each other. Fine vessels such as cephalic veins and branches of external jugular veins were noticeable but clear visualization was hindered by image noise in gadolinium‐specific (CTV) images, as reviewed by a neuroradiologist. In the small bowel imaging study, the mesenteric arteries and collapsed bowel wall containing iodine and the small bowel loops containing bismuth were clearly distinctive from each other in the iodine‐ and bismuth‐specific images after material decomposition, as reviewed by an abdominal radiologist. Quantitative analyses showed that the misclassifications between the two contrast materials were less than 1.7 and 0.1 mg/ml for CTA/CTV and small bowel imaging studies, respectively.ConclusionsFeasibility of simultaneous CTA/CTV imaging in head and neck with iodine and gadolinium and simultaneous imaging of arterial and enteric phases of small bowel with iodine and bismuth, using a dual‐source EID‐MECT system, was demonstrated in a swine study. Compared to iodine and gadolinium in CTA/CTV, better delineation and classification of iodine and bismuth in small bowel imaging were achieved mainly due to wider separation between the corresponding two K‐edge energies.

Abstract Objective Ensuring medication delivery to the epidural space is crucial for effective transforaminal epidural steroid injections. Epidural needle placement is determined by injecting a small amount of contrast at the final needle position. The purpose of this study is to illustrate the appearance of contrast flow in the retrodural retroligamentous space of Okada during computed tomography– and fluoroscopy-guided cervical and lumbar transforaminal epidural steroid injections. Design This retrospective study will use a series of cases to demonstrate contrast within the space of Okada during epidural transforaminal steroid injections. Setting Tertiary medical center. Subjects Study subjects are adult patients who underwent transforaminal epidural steroid injection at our institution. Methods Cases were identified through the use of a search engine of existing radiology reports at our institution. Epidural steroid injection procedural reports were searched for the terms “Okada” and “retrodural space.” Images from the procedure were reviewed by the authors (all proceduralists with dedicated training in spinal injections) to confirm the presence of contrast within the space of Okada. Results This case series illustrates six examples of contrast injection into the retrodural space of Okada during cervical and lumbar transforaminal epidural steroid injections. Conclusions Contrast uptake in the retrodural space of Okada may be seen during transforaminal epidural injections. Although relatively uncommon, it is likely underrecognized. It is extremely important that providers who perform transforaminal epidural steroid injections be familiar with this non-epidural contrast flow pattern so they can adjust needle positioning to deliver steroid to the epidural space.

This Practice Advisory presents a comprehensive and evidence-based set of position statements and recommendations for the use of contrast media in interventional pain procedures. The advisory was established by an international panel of experts under the auspices of 11 multinational and multispecialty organizations based on a comprehensive review of the literature up to December 31, 2019. The advisory discusses the risks of using gadolinium-based contrast agents. These include nephrogenic systemic fibrosis, gadolinium brain deposition/retention, and encephalopathy and death after an unintentional intrathecal gadolinium injection. The advisory provides recommendations on the selection of a specific gadolinium-based contrast agent in patients with renal insufficiency, those who had multiple gadolinium-enhanced magnetic resonance imaging examinations, and in cases of paraspinal injections. Additionally, recommendations are made for patients who have a history of mild, moderate, or severe hypersensitivity reactions to contrast medium.

Purpose Understanding all factors that may impact radiation dose and procedural time is crucial to safe and efficient image-guided interventions, such as fluoroscopically guided sacroiliac (SI) joint injections. The purpose of this study was to evaluate the effect of flow pattern (intra- vs. periarticular), patient age, and body mass index (BMI) on radiation dose and fluoroscopy time. Methods A total of 134 SI joint injections were reviewed. Injectate flow pattern, age, and BMI were analyzed in respect to fluoroscopy time (minutes), radiation dose (kerma area product (KAP); µGy m 2 ), and estimated skin dose (mGy). Results BMI did not affect fluoroscopy time, but increased BMI resulted in significantly higher skin and fluoroscopy doses ( p < 0.001). There was no association between fluoroscopy time and flow pattern. Higher skin dose was associated with intraarticular flow ( p = 0.0086), and higher KAP was associated with periarticular flow ( p = 0.0128). However, the odds ratios were close to 1. There was no significant difference between fluoroscopy time or dose based on patient age. Conclusion Increased BMI had the largest impact on procedural radiation dose and skin dose. Flow pattern also showed a statistically significant association with radiation dose and skin dose, but the clinical difference was small. Proceduralists should be aware that BMI has the greatest impact on fluoroscopy dose and skin dose during SI joint injections compared to other factors.

Case: A 41-year-old man sustained occipitocervical dislocation (OCD) and atlantoaxial dislocation (AAD) injuries in a motor vehicle collision. These injuries were treated nonoperatively with a hard cervical collar and activity restrictions with an excellent result at 4-year follow-up. Conclusion: OCD and AAD injuries require prompt diagnosis and immobilization. Standard of care for coexisting injuries is occipitocervical fusion; however, some patients have coexisting injuries which may prevent operative treatment. These polytrauma patients require a creative nonoperative approach with close follow-up to avoid neurologic decline.

Torus mandibularis is a benign osseous overgrowth arising from the lingual surface of the mandible. It is a common, incidental finding on imaging due to its relatively high prevalence. In the majority of cases, mandibular tori are asymptomatic. We report a novel presentation of a giant torus mandibularis causing bilateral obstruction of the submandibular ducts and consequent sialadenitis. Our patient presented with progressive pain centered in the floor of his mouth and had bilateral submandibular glandular enlargement on exam. Computed tomography showed a giant right torus mandibularis, which was causing obstruction and dilation of the bilateral submandibular ducts. Although conservative management was attempted, he ultimately underwent surgical resection of his torus with symptomatic improvement. This patient highlights a novel complication of torus mandibularis and illustrates successful treatment. Though not previously described, this complication may be underreported and should be considered in the appropriate clinical setting.