Added Value of Vessel Wall Magnetic Resonance Imaging in the Differentiation of Moyamoya Vasculopathies in a Non-Asian Cohort.

BACKGROUND AND PURPOSE: Although studies have evaluated the differential imaging of moyamoya disease and atherosclerosis, none have investigated the added value of vessel wall magnetic resonance imaging (MRI). This study evaluates the added diagnostic value of vessel wall MRI in differentiating moyamoya disease, atherosclerotic-moyamoya syndrome (A-MMS), and vasculitic-MMS (V-MMS) with a multicontrast protocol. METHODS: We retrospectively reviewed the carotid artery territories of patients with clinically defined vasculopathies (moyamoya disease, atherosclerosis, and vasculitis) and steno-occlusive intracranial carotid disease. Two neuroradiologists, blinded to clinical data reviewed the luminal imaging of each carotid, evaluating collateral extent and making a presumed diagnosis with diagnostic confidence. After 3 weeks, the 2 readers reviewed the luminal imaging+vessel wall MRI for the presence, pattern and intensity of postcontrast enhancement, T2 signal characteristics, pattern of involvement, and presumed diagnosis and confidence. RESULTS: Ten A-MMS, 3 V-MMS, and 8 moyamoya disease cases with 38 affected carotid segments were included. There was significant improvement in diagnostic accuracy with luminal imaging+vessel wall MRI when compared with luminal imaging (87% versus 32%, P<0.001). The most common vessel wall MRI findings for moyamoya disease were nonenhancing, nonremodeling lesions without T2 heterogeneity; for A-MMS eccentric, remodeling, and T2 heterogeneous lesions with mild/moderate and homogeneous/heterogeneous enhancement; and for V-MMS concentric lesions with homogeneous, moderate enhancement. Inter-reader agreement was moderate to substantial for all vessel wall MRI characteristics (κ=0.46-0.86) and fair for collateral grading (κ=0.35). There was 11% inter-reader agreement for diagnosis on luminal imaging when compared with 82% for luminal imaging+vessel wall MRI (P<0.001). CONCLUSIONS: Vessel wall MRI can significantly improve the differentiation of moyamoya vasculopathies when combined with traditional imaging techniques.

Articular cartilage degeneration in the contralateral non-surgical temporomandibular joint in mice with a unilateral partial discectomy.

OBJECTIVE: The objective was to characterize the contralateral non-surgical temporomandibular joint (TMJ) in mice that had an opposing osteoarthrosis(OA)-like joint induced by unilateral partial discectomy. METHODS: TMJs on one side in mice were subjected to partial discectomy. Both surgical and contralateral non-surgical TMJs were collected at 4, 8, 12 and 16 weeks post-surgery for histological examination. The morphology of the articular cartilage of the condyle was evaluated using a scoring system. RESULTS: A progression of articular cartilage degeneration was seen in the TMJs following unilateral partial discectomy, including increased proteoglycan staining in the extracellular matrix at 4 weeks, the appearance of chondrocyte clusters at 8 weeks, reduced proteoglycan staining and fibrillation at 12 weeks and the loss of articular cartilage at 16 weeks. In the contralateral non-surgical TMJs, increased proteoglycan staining occurred in the articular cartilage of the condyle at 8 weeks and continued to age. CONCLUSION: The result indicated that OA-like changes in one TMJ by partial discectomy could initiate early-onset articular cartilage degeneration in the contralateral non-surgical TMJ in mice.

Cervical collaterals may protect against stroke after blunt vertebral artery injury.

The incidence of ischemic stroke reported after blunt vertebral artery injury is lower than that reported after blunt carotid artery injury. Unlike the carotid arteries, the vertebral arteries receive collateral blood flow through ascending cervical branches in addition to a convergent arterial supply with the contralateral vertebral artery. We hypothesize that the incidence of stroke after vertebral artery injury is less than after carotid artery injury in part because of reconstitution of vertebral arteries by cervical collaterals. A retrospective blinded interpretation of angiographic studies in 46 patients with blunt vertebral injury was performed to assess for presence and grade of vertebral artery injury and for the presence of reconstitution of the vessel via cervical collaterals. Follow-up CT scans from the same patients were evaluated for the presence of posterior circulation strokes. There were 55 injured vertebral arteries in the 46 patients, of whom 8 experienced posterior fossa strokes. Two-tailed Fisher exact probability test evaluating the hypothesis that patients with vertebral artery collaterals were less likely to experience posterior fossa strokes reached significance, p < 0.05. Of patients with occlusive (grades IV and V) injuries, those with collateral vessels were significantly less likely to experience posterior fossa strokes (p < 0.01). This result may be considered when weighing the potential risks and benefits of antiplatelet or anticoagulation therapy in patients with occlusive blunt vertebral artery injury.

Radiation dose and excess risk of cancer in children undergoing neuroangiography.

OBJECTIVE: The primary goal of this study was to determine the radiation dose received during diagnostic and interventional neuroangiographic procedures in a group of pediatric patients. A second goal was to approximate the total average radiation dose from all angiographic and CT studies that pediatric patients underwent during the study period and to estimate the increased risk of cancer incidence in this patient group. MATERIALS AND METHODS: The study subjects were pediatric patients who had undergone one or more neuroangiographic procedures at Harborview Medical Center between December 1, 2004, and April 30, 2008. Recorded radiation doses were converted to entrance skin dose (ESD) and effective dose (ED) to indicate deterministic and stochastic damage, respectively. The Biologic Effects of Ionizing Radiation (BEIR) VII, phase 2, report was used to estimate the expected increased risk of cancer in the study population. RESULTS: For diagnostic and therapeutic procedures, a mean ED of 10.4 and 34.0 mSv per procedure was calculated, respectively. The ESD values proved too low to cause deterministic harm. The estimated number of excess cases of malignancy projected from the total average radiation exposure was 890.6 per 100,000 exposed male children and 1,222.5 per 100,000 exposed females, an overall increase of approximately 1% to the lifetime attributable risk of cancer. CONCLUSION: Although both angiography and CT have revolutionized the practice of medicine and confer benefits to patients, it is important that we continue to investigate the possible adverse effects of these technologies. Protocols that minimize radiation dose without compromising a study should be implemented.

Diffusion Tensor Imaging of the Spinal Cord: Clinical Value, Investigational Applications, and Technical Limitations.

Although diffusion-weighted imaging (DWI) has become a mainstay in modern brain imaging, it remains less utilized in the evaluation of the spinal cord. Many studies have shown promise in using DWI and diffusion-tensor imaging (DTI) for evaluation of the spinal cord; however, application has been stalled by technical obstacles and artifacts, and questions remain regarding its clinical utility on an individual examination level. This review discusses the background, concepts, and technical aspects of DWI and DTI, specifically for imaging of the spinal cord. The clinical and investigational applications of spinal cord DTI, as well as the practical difficulties and limitations of DWI and DTI for the evaluation of the spinal cord are examined.

Toward Quantifying the Prevalence, Severity, and Cost Associated With Patient Motion During Clinical MR Examinations.

PURPOSE: To assess the prevalence, severity, and cost estimates associated with motion artifacts identified on clinical MR examinations, with a focus on the neuroaxis. METHODS: A retrospective review of 1 randomly selected full calendar week of MR examinations (April 2014) was conducted for the detection of significant motion artifacts in examinations performed at a single institution on 3 different MR scanners. A base-case cost estimate was computed from recently available institutional data, and correlated with sequence time and severity of motion artifacts. RESULTS: A total of 192 completed clinical examinations were reviewed. Significant motion artifacts were identified on sequences in 7.5% of outpatient and 29.4% of inpatient and/or emergency department MR examinations. The prevalence of repeat sequences was 19.8% of total MRI examinations. The base-case cost estimate yielded a potential cost to the hospital of $592 per hour in lost revenue due to motion artifacts. Potential institutional average costs borne (revenue forgone) of approximately $115,000 per scanner per year may affect hospitals, owing to motion artifacts (univariate sensitivity analysis suggested a lower bound of $92,600, and an upper bound of $139,000). CONCLUSIONS: Motion artifacts represent a frequent cause of MR image degradation, particularly for inpatient and emergency department patients, resulting in substantial costs to the radiology department. Greater attention and resources should be directed toward providing practical solutions to this dilemma.

Evidence-based approach to using CT in spinal trauma.

Computed tomography has revolutionized the diagnosis and treatment planning of the acutely injured spine. In the cervical spine, its appropriate use can improve outcome and save money. Although there are no clinical prediction rules validated outside of the cervical spine, these proven capabilities have been extrapolated to the thoracolumbar spine.

Evidence-based approach to use of MR imaging in acute spinal trauma.

MR imaging directly shows integrity of spinal cord, and provides sensitive assessments of structurally important soft tissue investments of the vertebral column. High-resolution images should be acquired in at least two planes, with T1 and fluid sensitive sequences. In the acute and subacute settings, MR may be used to assess integrity of intervertebral discs prior to closed reduction of inter-facetal dislocations, to discriminate between neurological deficits due to intra-substance hemorrhage or edema, and to determine the status of spinal ligaments as an adjunct to 'clearing' the spine.

Accuracy of preliminary interpretation of neurologic CT examinations by on-call radiology residents and assessment of patient outcomes at a level I trauma center.

PURPOSE: The aims of this study were to evaluate the accuracy of preliminary interpretations of emergency neurologic CT scans after hours by on-call radiology residents and to assess the clinical impact of residents' errors at a level I trauma center. METHODS: A quality assurance database of neurologic CT examinations was reviewed to compare preliminary interpretations by on-call residents with final analyses by attending neuroradiologists during a 12-month period. All disagreements were reviewed for confirmation of the findings and categorized as significant or nonsignificant. Significant errors were further classified as acute intracranial, acute extracranial, and nonacute. Medical records for scans with significant errors were reviewed to evaluate any negative impact on the patient for each significant case. Residents' postgraduate years were also recorded. RESULTS: There were 252 cases (3.7%) with disagreements among 6,852 total cases. Of those, 226 (3.3%) were confirmed as resident errors, which included 171 (2.5%) that were significant. There were 73 (1.1%) acute intracranial, 77 (1.1%) acute extracranial, and 21 (0.3%) nonacute misinterpretations. Among the 171 significant cases, 105 (1.5%) had no changes in clinical management, and 55 (0.8%) required some changes. CONCLUSION: The rate of significant errors by on-call radiology residents was low. These errors had a minimal impact on clinical outcomes. Continued monitoring of residents' performance is important to maintain or improve patient safety.

Radiologic and clinical spectrum of occipital condyle fractures: retrospective review of 107 consecutive fractures in 95 patients.

OBJECTIVE: We proposed to characterize the radiologic spectrum of occipital condyle fractures in a large series of patients and to correlate fracture pathology with neurosurgical treatment and patient outcome. MATERIALS AND METHODS: We conducted a retrospective review of the findings on conventional radiography, CT, and MR imaging in 95 patients with 107 occipital condyle fractures. We described fracture patterns according to two previously published classification systems. Clinical findings, neurosurgical management, and patient outcome were obtained from the medical records. RESULTS: Inferomedial avulsions (Anderson and Montesano type III) were the most common type of occipital condyle fracture, constituting 80 (75%) of 107 overall fractures. Unilateral occipital condyle fractures were found in 73 (77%) of 95 patients, and 58 patients were treated nonoperatively; occipitocervical fusion was required in nine patients for complex C1-C2 injuries, and six patients died. Bilateral occipital condyle fractures or occipitoatlantoaxial joint injuries were seen in 22 (23%) of 95 patients. Occipitocervical fusion or halo traction for the craniocervical junction was required in 12 patients, all of whom had CT evidence of bilateral occipitoatlantoaxial joint disruption and six of whom showed normal craniocervical relationships on conventional radiographs. Six patients with nondisplaced fractures were treated nonoperatively, and four patients died. Thirty (32%) of 95 patients showed continued disability, whereas 55 (57.5%) of 95 patients had good outcomes at 1 month. Associated cervical spine injuries were present in 29 (31%) of 95 patients. CONCLUSION: Given their associated traumatic brain and cervical spine injuries, occipital condyle fractures are markers of high-energy traumas. That conventional radiographs alone may miss up to half of the patients with acute craniocervical instability has not been well established. Avulsion fracture type and fracture displacement are associated with both injury mechanism and the need for surgical stabilization. In this series, most unilateral occipital condyle fractures were treated nonoperatively, whereas bilateral occipitoatlantoaxial joint injuries with findings of instability usually required surgical stabilization.