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Purpose: Following spinal instrumentation and fusion, differentiating between successful arthrodesis and pseudoarthrosis on imaging can be challenging. Interpretation of such examinations requires understanding both the expected evolution of postoperative findings and the subtle indicators of pseudoarthrosis across multiple imaging modalities. Due to this level of intricacy, many clinicians lack familiarity with the subject beyond the more rudimentary concepts. Methods: This review provides an in-depth overview of the imaging of the post-operative spine, with particular emphasis on differentiating between pseudoarthrosis and arthrodesis. Results: A comprehensive overview of imaging of the post-operative spine is given, including the most common imaging modalities utilized, the expected post-operative findings, imaging findings in pseudoarthrosis, and imaging definitions of fusion. Conclusion: Differentiating between pseudoarthrosis and arthrodesis in the postoperative spine is complex, and requires a robust understanding of various findings across many different modalities. [ABSTRACT FROM AUTHOR]

Objectives The S1 dorsal foramen is the route for 30% of lumbar transforaminal epidural injections; it is therefore important to identify structures impeding S1 foraminal access. The study objective was to characterize the imaging findings, prevalence, and anatomic origin of synovial cysts presenting within the S1 neural foramen. Methods A case series (N = 14) established imaging characteristics of S1 synovial cysts. Imaging studies of 400 patients undergoing epidural injections were reviewed for lesions compromising S1 foraminal access. Cadaveric dissections defined the relationship of the inferior recess of the L5-S1 facet to the S1 dorsal foramen. Results Elderly patients (mean age = 76) exhibited S1 synovial cysts. Synovial cysts were typically 1–2 cm in diameter, hyperintense on sagittal T2 weighted magnetic resonance images (MRIs), fluid-density on computed tomography, and dorsal to the S1 spinal nerve. Sixty percent of cysts exhibited complex MRI signal characteristics (thick wall, internal structure). Tarlov cysts, in contrast, were larger, lobular, and exhibited pure fluid intensity. Lesions impeded access to the S1 dorsal foramina in 5% of reviewed imaging studies (16 Tarlov cysts, three synovial cysts, one conjoint S1-S2 nerve root). The multifidus muscle was interposed between the L5-S1 facet inferior recess and the S1 dorsal foramen on dissection specimens; severe atrophy of the ipsilateral multifidus was noted on imaging in 17/18 synovial cysts. Conclusions The S1 neural foramina should be inspected on sagittal MRI, when available, for confounding lesions before performing S1 epidural injections. Tarlov cysts are more common than synovial cysts; the latter are seen in elderly patients with severe multifidus atrophy. [ABSTRACT FROM AUTHOR]

• Considering all patients, no significant difference in morphology between groups. • Lower incidence of medium and large regular saccular aneurysms in the ADPKD group. • Higher incidence of medium and large fusiform aneurysms in the ADPKD group. • Further study of this population of patients is warranted. Approximately 8% of patients with autosomal dominant polycystic kidney disease (ADPKD) develop intracranial aneurysms. The reason for development of intracranial aneurysms in ADPKD patients might be related to interactions between the presence of hypertension and the basic mechanism underlying the disease, which leads to weakness of the connective tissue. In this study, we aimed to identify differences in aneurysm morphology between ADPKD patients and a location-matched set of controls. A total of 42 ADPKD patients and 49 control patients with 122 aneurysms were included. Aneurysm size, location, and morphology were evaluated by two neuroradiologists. Aneurysm morphology was classified into one of three groups: regular saccular, irregular saccular, and fusiform. Continuous variables were compared with chi-squared tests and categorical variables were compared with student's t -test. When considering all patients, there was no significant difference in aneurysm morphology or size (4.5 ± 2.6 mm vs 5.4 ± 2.9 mm; p = 0.09) between the ADPKD and control group. In a subgroup analysis of medium and large aneurysms (n = 61), there was a significantly lower incidence of regular saccular aneurysms (28% vs. 56%; p = 0.03) and higher incidence of fusiform aneurysms (12% vs 0%; p = 0.03) in the ADPKD group compared to a control group. When excluding categorically "small" aneurysms, there is a reduced incidence of regular saccular aneurysms and increased incidence of fusiform aneurysms in ADPKD patients compared to a control group. Further study of this population of patients is warranted to better understand their risks of aneurysm rupture and indications for treatment. [ABSTRACT FROM AUTHOR]

background and purpose Vertebrobasilar dolichoectatic and fusiform aneurysms (VBDAs) are known to have a poor natural history, with high rates of growth, rupture, and stroke. The purpose of this study was to identify hemodynamic characteristics that differ between VBDAs associated with growth, rupture, and stroke. Materials and methods VBDAs with CT angiography or MR angiography followed longitudinally without treatment were studied. Unstable aneurysms were defined as those that grew or ruptured during follow-up. aneurysms associated with stroke were defined as those associated with posterior circulation infarct at follow-up. Baseline data, including demographics, comorbidities, and aneurysm morphology and size were collected. image based computational fluid dynamics models were created and run under pulsatile flow conditions. relevant hemodynamic and geometric variables were calculated and compared between groups (stable vs unstable and no stroke vs stroke) using the Wilcoxon test. results a total of 37 VBDas were included (24 stable, 13 unstable; 30 no stroke, 7 stroke). Unstable aneurysms had lower shear rates (P=0.05), blood flow velocity (P=0.03), and lower vorticity (P=0.049) than stable aneurysms. in addition, unstable aneurysms had higher mean oscillatory shear indices (P=0.001). There were no differences in the hemodynamic characteristics of aneurysms in the stroke group compared with the nonstroke group. Conclusion This small study suggests there may be hemodynamic differences between unstable and stable VBDas. Unstable VBDas appear to be under lower flow conditions with lower velocity, vorticity, and shear rates, and have more oscillatory flow. There was no difference in the hemodynamic characteristics of aneurysms in the stroke and no stroke group. [ABSTRACT FROM AUTHOR]

Purpose: A recently identified and treatable cause of spontaneous intracranial hypotension (SIH) is cerebrospinal fluid (CSF)-venous fistula, and a recently described computed tomography myelogram (CTM) finding highly compatible with but not diagnostic of this entity is the hyperdense paraspinal vein sign. We aimed to retrospectively measure the prevalence of the hyperdense paraspinal vein sign on CTMs in SIH patients without dural CSF leak, in comparison with control groups.Methods: Three CTM groups were identified: 1) SIH study group, which included dural CSF leak-negative standard CTMs performed for SIH, with early and delayed imaging; 2) Early control CTMs, which were performed for indications other than SIH, with imaging shortly after intrathecal contrast administration; 3) Delayed control CTMs, which included delayed imaging. CTMs were retrospectively reviewed for the hyperdense paraspinal vein sign by experienced neuroradiologists, blinded to the group assignment. All CTMs deemed by a single reader to be positive for the hyperdense paraspinal vein sign were independently reviewed by two additional neuroradiologists; findings were considered positive only if consensus was present among all three readers. For positive cases, noncontrast CTs and prior CTMs, if available, were reviewed for the presence of the sign.Results: Seven of 101 (7%) SIH patients had contrast in a spinal/paraspinal vein consistent with the hyperdense paraspinal vein sign; no patient in either control group (total n=54) demonstrated the hyperdense paraspinal vein sign (P = 0.0463). The finding occurred only at thoracic levels. Each patient had a single level of involvement. Six (86%) occurred on the right. Four occurred in female patients (57%). The sign was seen on early images in 3 of 7 cases (43%) and on both early and delayed images in 4 of 7 cases (57%). In 2 of 7 patients (29%), a noncontrast CT covering the relevant location was available and negative for the sign. A prior CTM was available in 2 of 7 patients (29%), and in both cases the hyperdense paraspinal vein sign was also evident.Conclusion: The prevalence of the hyperdense paraspinal vein sign in SIH patients with dural CSF leak-negative standard CTM was 7%. As the sign was not seen in control groups, this sign is highly compatible with the presence of CSF-venous fistula. Since the CTMs were not specifically dedicated to identifying hyperdense paraspinal veins (i.e., they were not dynamic and were not preceded by digital subtraction myelography), the true prevalence of the sign may be higher. Radiologists should scrutinize conventional CTMs for this sign, especially in patients in whom a traditional dural CSF leak is not identified. [ABSTRACT FROM AUTHOR]

Objective. To examine associations between imaging characteristics of compressive lesions and patient outcomes after lumbar transforaminal epidural steroid injections (TFESIs) stratified by steroid formulation (solution versus suspension). Design/Subjects. Retrospective observational study, academic radiology practice. A 516-patient sample was selected from 2,634 consecutive patients receiving lumbar TFESI for radicular pain. Methods. The advanced imaging study(s) preceding sampled TFESI were reviewed. Compressive lesions were described by a) nature of the lesion [disc herniation, fixed stenosis, synovial cyst, epidural fibrosis, no lesion] b) degree of neural compression [4 part scale], and c) presence of a tandem lesion. Associations between 2-month categorical outcomes (responder rates for pain, functional recovery) and imaging characteristics, stratified by steroid formulation, were examined with chi-squared tests of categorical outcomes and multivariable logistic regression models. Results. Disc herniation patients had more responders for functional recovery than patients with fixed lesions (54% versus 38%, P=0.01). Patients with fixed lesions receiving steroid solution (dexamethasone) had more responders for pain relief, with a similar trend for functional recovery, than patients receiving suspensions (59% versus 40%, P5=0.01). Outcomes for patients with fixed lesions treated with dexamethasone were not statistically different from those for disc herniation patients. Patients with single compressive lesions had more responders than those with tandem lesions (55% versus 41%, P=0.03). Conclusion. In the entire sample, outcomes for disc herniations were more favorable than for fixed lesions. However, fixed lesions treated with dexamethasone had outcomes indistinguishable from disc herniations. Single lesions had better outcomes than tandem lesions. [ABSTRACT FROM AUTHOR]

Purpose: We compared signal change on magnetic resonance imaging (MRI) with fat suppression and bone scan activity of lumbar facet joints to determine if these two imaging findings are correlated.Methods: We retrospectively identified all patients who underwent imaging of the lumbar spine for pain evaluation using both technetium-99m methylene disphosphonate single-photon emission computed tomography/computed tomography (99mTc-MDP SPECT/CT) and MRI with at least one fat-suppressed T2- or T1-weighted sequence with gadolinium enhancement within a 180-day interval, at our institution between 1 January 2008 and 19 February 2013. Facet joint activity on 99mTc-MDP SPECT/CT and peri-facet signal change on MRI were rated as normal or increased. Agreement between the two examination types were determined with the κ and prevalence-adjusted bias-adjusted κ (PABAK) statistics.Results: This study included 60 patients (28 male, 47%), with a mean age of 49±19.7 years (range, 12-93 years). The κ value indicated no agreement between 99mTc-MDP SPECT/CT and MRI (κ=-0.026; 95% confidence interval: -0.051, 0.000). The PABAK values were fair to high at each spinal level, which suggests that relatively low disease prevalence lowered the κ values. Together, the κ and PABAK values indicate that there is some degree of intermodality agreement, but that it is not consistent.Conclusion: Overall, facet joint signal change on fat-suppressed MRI did not always correlate with increased 99mTc-MDP SPECT/CT activity. MRI and 99mTc-MDP SPECT/CT for facet joint evaluation should not be considered interchangeable examinations in clinical practice or research. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to assess the accuracy of oculopneumoplethysmography (OPG) for the diagnosis of carotid artery stenosis both alone and in conjunction with carotid magnetic resonance angiography (MRA). Methods: This retrospective study reviewed patients who had undergone both OPG and digital subtraction angiography (DSA, 90 patients, 174 vessels) within two weeks to determine the accuracy of OPG with DSA as the reference standard for the detection of carotid artery stenosis. Three carotid artery stenosis thresholds (≥50%, ≥70%, ≥80%) were analyzed. The accuracy of the combination of OPG and MRA was analyzed in a subset of patients who underwent OPG and MRA and DSA (53 patients, 94 vessels). Results: The sensitivity and negative predictive value of OPG increased with higher-degree carotid artery stenoses, and for lesions ≥ 80%, these values were 85.3% and 94.2%, respectively. Specificity and positive predictive values were lower at all thresholds, and were 72.9% and 49.3%, respectively, at the ≥80% stenosis threshold. When OPG and MRA were concordant, the sensitivity and specificity for carotid artery stenoses ≥ 80% were 91.0% and 97.8%, respectively. OPG correctly identified 71.4% of false-positive and 80.0% of false-negative magnetic resonance angiographies for that degree of carotid artery stenosis. Conclusion: OPG appears to be an accurate rule-out test for hemodynamically significant carotid artery stenosis. OPG augments the accuracy of MRA for detection of carotid artery disease. [ABSTRACT FROM AUTHOR]

Background: Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare presentation of a primary central nervous system glial tumor. Methods: Four case reports of PDLG in young males aged 14–24 years are presented. These reports are discussed in the context of the existing literature. Results: The clinical presentation of 4 new cases of PDLG resembled chronic meningitis with and without polyradiculopathy. Spinal fluid studies are typically nondiagnostic, but characteristically show elevated opening pressure, an elevated protein level, and a relative paucity of cellular reaction. An accurate antemortem diagnosis required contrast-enhanced imaging and meningeal biopsy in all 4 of our cases. Treatment strategies including craniospinal radiation and chemotherapeutic approaches, alone or in combination, have not been proven to alter the course of the disease. Initial responses to temozolomide and radiation treatments in all 4 of our cases were promising, resulting in temporary stabilization of the disease and prolonging life expectancy over what was previously reported in the literature. Conclusion: Total neuroaxis contrast-enhanced MRI scanning is required for directing biopsy confirmation and detecting the extent of the disease. More effective therapeutic strategies are needed, but the combination of temozolomide and radiation therapy may slow disease progression. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

By leveraging its experience and expertise as a consultative clinical partner, the Mayo Clinic developed an innovative, scalable care model to accomplish several strategic goals: (1) create and sustain high-value relationships that benefit patients and providers, (2) foster relationships with like-minded partners to act as a strategy against the development of narrow health care networks, and (3) increase national and international brand awareness of Mayo Clinic. The result was the Mayo Clinic Care Network. [ABSTRACT FROM AUTHOR]