Kent R. Thielen

Intracranial Gadolinium Deposition after Contrast-enhanced MR Imaging

PURPOSE To determine if repeated intravenous exposures to gadolinium-based contrast agents (GBCAs) are associated with neuronal tissue deposition. MATERIALS AND METHODS In this institutional review board-approved single-center study, signal intensities from T1-weighted magnetic resonance (MR) images and postmortem neuronal tissue samples from 13 patients who underwent at least four GBCA-enhanced brain MR examinations between 2000 and 2014 (contrast group) were compared with those from 10 patients who did not receive GBCA (control group). Antemortem consent was obtained from all study participants. Neuronal tissues from the dentate nuclei, pons, globus pallidus, and thalamus of these 23 deceased patients were harvested and analyzed with inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy, and light microscopy to quantify, localize, and assess the effects of gadolinium deposition. Associations between cumulative gadolinium dose, changes in T1-weighted MR signal intensity, and ICP-MS-derived tissue gadolinium concentrations were examined by using the Spearman rank correlation coefficient (ρ). RESULTS Compared with neuronal tissues of control patients, all of which demonstrated undetectable levels of gadolinium, neuronal tissues of patients from the contrast group contained 0.1-58.8 μg gadolinium per gram of tissue, in a significant dose-dependent relationship that correlated with signal intensity changes on precontrast T1-weighted MR images (ρ = 0.49-0.93). All patients in the contrast group had relatively normal renal function at the time of MR examination. Gadolinium deposition in the capillary endothelium and neural interstitium was observed only in the contrast group. CONCLUSION Intravenous GBCA exposure is associated with neuronal tissue deposition in the setting of relatively normal renal function. Additional studies are needed to investigate the clinical significance of these findings and the generalizability to other GBCAs. Online supplemental material is available for this article.

Intra-arterial Thrombolysis in Acute Basilar Artery Thromboembolism: The Initial Mayo Clinic Experience

OBJECTIVE To investigate the feasibility of intra-arterial thrombolysis in acute basilar artery thrombosis. DESIGN We reviewed a consecutive series of patients in whom intra-arterial thrombolysis was performed during the period from 1994 to 1996. MATERIAL AND METHODS Intra-arterial thrombolysis with urokinase was done in an attempt to recanalize the basilar artery in a series of nine patients with basilar artery thrombosis admitted to the neurologic intensive care unit. At the time of initial assessment, all nine patients had major neurologic deficits attributable to brain-stem ischemia, including two patients with locked-in syndrome. RESULTS Recanalization of the basilar artery system was successful in seven of the nine patients (a range of 2 to 13 hours after the ictus). Failure to recanalize the basilar artery occurred in two patients, who died after progressing to coma. Complete recovery or only minimal neurologic deficits were demonstrated in five of the nine patients. Despite recanalization of the basilar artery, two patients had no major change in their neurologic function, and both ultimately had severe ataxia and were fully dependent on others. A cerebellar hemorrhage occurred in one patient but without clinical worsening. Two patients had a retroperitoneal hematoma. CONCLUSION Intra-arterial thrombolysis with urokinase in acute basilar artery occlusion resulted in recanalization in seven of the nine patients (78%). Five of the nine patients recovered fully, including two patients who had had locked-in syndrome. In light of the devastating natural course of acute basilar artery occlusion, these initial results are encouraging and indicate that intra-arterial thrombolysis may be a useful emergency treatment, even in patients with prolonged symptoms of ischemia (up to 12 hours).

Vertebroplasty in Multiple Myeloma: Outcomes in a Large Patient Series

BACKGROUND AND PURPOSE: Despite the literature supporting the efficacy of vertebroplasty for treatment of osteoporotic vertebral compression fractures, few reports exist documenting its use in the treatment of compression fractures in multiple myeloma patients. Accordingly, we sought to characterize the imaging characteristics, clinical course, and outcomes in myeloma patients treated with vertebroplasty. MATERIALS AND METHODS: We performed a retrospective review of clinical outcome data from 67 multiple myeloma patients treated with vertebroplasty since October 2000. Quantitative outcome data including the Roland Morris Disability Questionnaire (RDQ) and Visual Analog Scales for pain and qualitative outcome data (self-reported pain, mobility, and narcotic use) were collected preoperatively, immediately after vertebroplasty, and at 1 week, 1 month, 6 months, and 1 year after treatment. RESULTS: Significant improvements in all of the outcome measures were observed postoperatively and throughout the duration of follow-up. Quantitative outcome measures (RDQ, analog pain scale 0–10, with rest and activity) improved by 11.0 (48%; P < .0001), 2.7 (25%; P < .001), and 5.3 (48%; P < .0001) points, respectively, with persistent improvement at 1 year (P < .01; P < .03; P < .001). Eighty-two percent and 89% of patients experienced a significant improvement in subjective rest pain and activity pain, respectively. Subjective scores achieved durable improvements, with 65% of patients requiring fewer narcotics after vertebroplasty and 70% having improved mobility. CONCLUSION: Vertebroplasty provides significant and durable pain relief for patients with intractable spinal pain secondary to compression fractures resulting from multiple myeloma.

The Noninferiority of the Nonparticulate Steroid Dexamethasone vs the Particulate Steroids Betamethasone and Triamcinolone in Lumbar Transforaminal Epidural Steroid Injections

OBJECTIVE To assess whether a nonparticulate steroid (dexamethasone, 10 mg) is less clinically effective than the particulate steroids (triamcinolone, 80 mg; betamethasone, 12 mg) in lumbar transforaminal epidural steroid injections (TFESIs) in subjects with radicular pain with or without radiculopathy. DESIGN Retrospective observational study with noninferiority analysis of dexamethasone relative to particulate steroids. SETTING Single academic radiology pain management practice. SUBJECTS Three thousand six hundred forty-five lumbar TFESIs at the L4-5, L5-S1, or S1 neural foramina, performed on 2,634 subjects. METHODS/OUTCOME MEASURES Subjects were assessed with a pain numerical rating scale (NRS, 0-10) and Roland-Morris disability questionnaire (R-M) prior to TFESI, and at 2 weeks and 2 months follow-up. For categorical outcomes, successful pain relief was defined as either ≥50% reduction in NRS or pain 0/10; functional success was defined as ≥40% reduction in R-M score. Noninferiority analysis was performed with δ = -10% as the limit of noninferiority. Continuous outcomes (mean NRS, R-M scores) were analyzed for noninferiority with difference bounds of 0.3 for NRS scores and 1.0 for R-M scores. RESULTS With categorical outcomes, dexamethasone was demonstrated to be noninferior to the particulate steroids in pain relief and functional improvement at 2 months. Using continuous outcomes, dexamethasone was demonstrated to be superior to the particulate steroids in both pain relief and functional improvement at 2 months. CONCLUSION This retrospective observational study reveals no evidence that dexamethasone is less effective than particulate steroids in lumbar TFESIs performed for radicular pain with or without radiculopathy.

Vertebral Endplate Fractures: An Indicator of the Abnormal Forces Generated in the Spine After Vertebroplasty

Vertebroplasty alters spinal biomechanics and may lead to incident vertebral fractures. The endplate localization of prevalent and incident fractures was evaluated in 86 patients. In the absence of vertebroplasty, superior endplate fractures predominate. After the procedure, inferior endplate fractures are disproportionately common in adjacent vertebrae immediately above the treated level, potentially supporting a causative relationship between vertebroplasty and incident fractures.

The Role of Digital Subtraction Myelography in the Diagnosis and Localization of Spontaneous Spinal CSF Leaks

OBJECTIVE The objective of our study was to review the clinical utility of digital subtraction myelography for the diagnosis of spinal CSF leaks in patients with spontaneous intracranial hypotension (SIH) and those with superficial siderosis. MATERIALS AND METHODS Procedure logs from 2007 to 2011 were reviewed to identify cases in which digital subtraction myelography was performed to diagnose spinal CSF leaks. Electronic medical records were reviewed to obtain information regarding diagnosis and outcome. For patients to be included in the study, preprocedural spinal MRI had to show an extradural fluid collection spanning more than one vertebral level and postmyelographic CT had to confirm the presence of an active CSF leak. If digital subtraction myelography successfully showed the site of the CSF leak, the location was documented. RESULTS Eleven patients (seven men and four women; mean age, 49.0 years) underwent digital subtraction myelography during the study period. Six patients had SIH and five patients had superficial siderosis. The extradural fluid collection on spinal MRI averaged a length of 15.5 vertebral levels. Digital subtraction myelography successfully showed the site of the CSF leak in nine of the 11 patients, and all of the dural tears were located in the thoracic spine between T3 and T11. CONCLUSION Digital subtraction myelography is a valuable diagnostic tool for the localization of rapid spinal CSF leaks and should be considered in patients who are clinically suspected to have a dural tear that is accompanied by a longitudinally extensive extradural fluid collection on spinal MRI.

3D C-Arm Conebeam CT Angiography as an Adjunct in the Precise Anatomic Characterization of Spinal Dural Arteriovenous Fistulas

BACKGROUND AND PURPOSE: Precise anatomic understanding of the vascular anatomy of SDAVFs is required before treatment. This study demonstrates the utility of C-arm conebeam CT to locate precisely the fistulous point in SDAVFs and the courses of their feeding arteries and draining veins. MATERIALS AND METHODS: This retrospective study reports 14 consecutive patients with SDAVFs who underwent DSA and C-arm conebeam CT angiography. SDAVF sites included 5 thoracic, 7 lumbar, and 2 sacral fistulas. Selective DSA initially identified the location and arterial supply of the SDAVF. C-arm conebeam CT angiography was then performed with selective injection into the feeding artery. Reconstructed images were reviewed at a workstation with the referring surgeon, in conjunction with the standard 2D DSA images. The value of C-arm conebeam CT in depicting the fistula and the relationship to adjacent structures was qualitatively assessed. RESULTS: In all 14 patients, C-arm conebeam CT angiography was technically successful and precisely demonstrated the site of the fistula, feeding arteries, draining veins, and the relationship of the fistula to adjacent osseous structures. Information obtained from the C-arm conebeam CT angiogram was considered useful in all surgically (12 patients) and endovascularly (2 patients) treated SDAVFs. CONCLUSIONS: 3D C-arm conebeam CT angiography is a useful adjunct to 2D DSA in the anatomic characterization of SDAVFs. The technique allowed improved visualization of the vascular anatomy of the SDAVFs and clearer definition of their spatial relationships to adjacent structures.

Clinical effectiveness of single lumbar transforaminal epidural steroid injections

OBJECTIVES To assess the clinical effectiveness of single lumbar transforaminal epidural steroid injections (TFESIs) in subjects with radicular pain with or without radiculopathy. DESIGN Retrospective observational series. SETTING Single academic radiology pain management practice. SUBJECTS Two thousand twenty-four subjects undergoing single lumbar TFESIs at the L4-5, L5-S1, or S1 neural foramina. METHODS / OUTCOME MEASURES Subjects were assessed with a pain numerical rating scale (NRS, 0-10) and Roland-Morris disability questionnaire (R-M, 23-point Deyo modification) prior to TFESI and at 2 weeks and 2 months follow-up. Successful pain relief (responders) was defined as either ≥50% reduction in NRS or pain 0/10; functional success was defined as ≥40% reduction in R-M score. RESULTS There were statistically significant (P < 0.0001) reductions in mean NRS and R-M scores at 2 weeks and 2 months postinjection. For NRS, 40.9% were responders at 2 weeks and 45.6% at 2 months. For R-M, 31.9% were responders at 2 weeks and 41.3% at 2 months. The proportion of responders for NRS and R-M was higher when there was <3 months of pain (odds ratio 2-month NRS = 2.42 [95% confidence interval: 1.82, 3.24], odds ratio 2-month R-M = 2.61 [1.96, 3.48]). For subjects with <3 months of pain, the proportion of responders was 62.4% (56.5, 68.3%) for NRS and 59.3% (53.3, 65.3%) for R-M scores. CONCLUSIONS This retrospective observational study suggests TFESIs are clinically effective in the treatment of lumbar radicular pain. Subjects with a shorter duration of pain are more likely to achieve a successful outcome.

Safety and Efficacy of CT-Guided Transforaminal Cervical Epidural Steroid Injections Using a Posterior Approach

BACKGROUND AND PURPOSE: Image-guided cervical transforaminal epidural injections play an important role in the management of cervical radicular pain syndromes. The safety and efficacy of these injections via an anterolateral approach has been well-studied. The goal of this retrospective review was to determine the safety and efficacy of CT-guided transforaminal epidural injections by using a posterior approach. MATERIALS AND METHODS: Retrospective review of patient records was used to define VNPS and RMDI of patients undergoing CT-guided transforaminal cervical epidural injections between 2006 and 2010. Pain scores were recorded preprocedure, immediately postprocedure, at 2 weeks, and at 2 months. The RMDI was recorded preprocedure, at 2 weeks, and at 2 months. Data analysis of 247 patients was completed. Differences in VNPS scores and the RMDI were then compared on the basis of a CT-guided approach (anterolateral versus posterior). RESULTS: There was no statistical difference in the degree of pain relief and improvement in the RMDI between the CT-guided transforaminal anterolateral approach and the posterior approach at 2 weeks and at 2 months. Both groups demonstrated a statistically significant improvement in pain scores and the RMDI. Approximately 35% of patients in both groups demonstrated >50% pain relief at 2 months. There were no serious complications in either group. CONCLUSIONS: CT-guided transforaminal cervical epidural injections by using a posterior approach are safe and effective.

Giant Cell (Temporal) Arteritis: Involvement of the Vertebral and Internal Carotid Arteries

We report the radiographic findings in a case of histologically proven giant cell (temporal) arteritis coupled with high-grade stenoses affecting the internal carotid and vertebral arteries. The 69-year-old patient sought medical assessment because of transient ischemic attacks. The stenoses, which were extradural just proximal to the dural entry point, were thought to be a manifestation of the giant cell arteritis.