MED: Radiology Papers
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Item Concussion, microvascular injury, and early tauopathy in young athletes after impact head injury and an impact concussion mouse model(OXFORD UNIV PRESS, 2018-02-01) Tagge, Chad A.; Fisher, Andrew M.; Minaeva, Olga V.; Gaudreau-Balderrama, Amanda; Moncaster, Juliet A.; Zhang, Xiao-Lei; Wojnarowicz, Mark W.; Casey, Noel; Lu, Haiyan; Kokiko-Cochran, Olga N.; Saman, Sudad; Ericsson, Maria; Onos, Kristen D.; Veksler, Ronel; Senatorov, Vladimir V.; Kondo, Asami; Zhou, Xiao Z.; Miry, Omid; Vose, Linnea R.; Gopaul, Katisha R.; Upreti, Chirag; Nowinski, Christopher J.; Cantu, Robert C.; Alvarez, Victor E.; Hildebrandt, Audrey M.; Franz, Erich S.; Konrad, Janusz; Hamilton, James A.; Hua, Ning; Tripodis, Yorghos; Anderson, Andrew T.; Howell, Gareth R.; Kaufer, Daniela; Hall, Garth F.; Lu, Kun P.; Ransohoff, Richard M.; Cleveland, Robin O.; Kowall, Neil W.; Stein, Thor D.; Lamb, Bruce T.; Huber, Bertrand R.; Moss, William C.; Friedman, Alon; Stanton, Patric K.; McKee, Ann C.; Goldstein, Lee E.The mechanisms underpinning concussion, traumatic brain injury, and chronic traumatic encephalopathy, and the relationships between these disorders, are poorly understood. We examined post-mortem brains from teenage athletes in the acute-subacute period after mild closed-head impact injury and found astrocytosis, myelinated axonopathy, microvascular injury, perivascular neuroinflammation, and phosphorylated tau protein pathology. To investigate causal mechanisms, we developed a mouse model of lateral closed-head impact injury that uses momentum transfer to induce traumatic head acceleration. Unanaesthetized mice subjected to unilateral impact exhibited abrupt onset, transient course, and rapid resolution of a concussion-like syndrome characterized by altered arousal, contralateral hemiparesis, truncal ataxia, locomotor and balance impairments, and neurobehavioural deficits. Experimental impact injury was associated with axonopathy, blood–brain barrier disruption, astrocytosis, microgliosis (with activation of triggering receptor expressed on myeloid cells, TREM2), monocyte infiltration, and phosphorylated tauopathy in cerebral cortex ipsilateral and subjacent to impact. Phosphorylated tauopathy was detected in ipsilateral axons by 24 h, bilateral axons and soma by 2 weeks, and distant cortex bilaterally at 5.5 months post-injury. Impact pathologies co-localized with serum albumin extravasation in the brain that was diagnostically detectable in living mice by dynamic contrast-enhanced MRI. These pathologies were also accompanied by early, persistent, and bilateral impairment in axonal conduction velocity in the hippocampus and defective long-term potentiation of synaptic neurotransmission in the medial prefrontal cortex, brain regions distant from acute brain injury. Surprisingly, acute neurobehavioural deficits at the time of injury did not correlate with blood–brain barrier disruption, microgliosis, neuroinflammation, phosphorylated tauopathy, or electrophysiological dysfunction. Furthermore, concussion-like deficits were observed after impact injury, but not after blast exposure under experimental conditions matched for head kinematics. Computational modelling showed that impact injury generated focal point loading on the head and seven-fold greater peak shear stress in the brain compared to blast exposure. Moreover, intracerebral shear stress peaked before onset of gross head motion. By comparison, blast induced distributed force loading on the head and diffuse, lower magnitude shear stress in the brain. We conclude that force loading mechanics at the time of injury shape acute neurobehavioural responses, structural brain damage, and neuropathological sequelae triggered by neurotrauma. These results indicate that closed-head impact injuries, independent of concussive signs, can induce traumatic brain injury as well as early pathologies and functional sequelae associated with chronic traumatic encephalopathy. These results also shed light on the origins of concussion and relationship to traumatic brain injury and its aftermath.Item Longitudinal assessment of cyst-like lesions of the knee and their relation to radiographic osteoarthritis and MRI-detected effusion and synovitis in patients with knee pain(BioMed Central, 2010-9-15) Hayashi, Daichi; Roemer, Frank W.; Dhina, Zineb; Kwoh, C. Kent; Hannon, Michael J.; Moore, Carolyn; Guermazi, AliINTRODUCTION. The purpose of the present study was to determine the prevalence of cystic lesions and cyst-like bursitides in subjects with frequent knee pain and to assess their relation to radiographic osteoarthritis (OA) severity; to describe bilaterality and size fluctuation of the lesions over 6 months; and to assess relations between the prevalence of synovium-lined lesions communicating with the joint capsule and severity of magnetic resonance imaging (MRI)-detected effusion and synovitis. METHODS. One hundred and sixty-three subjects (total 319 knees) aged 35 to 65 with chronic, frequent knee pain were included. Imaging with 3 Tesla MRI was performed at baseline and 6-month follow-up with the same protocols as those used in the Osteoarthritis Initiative. Severity of radiographic OA was assessed using the Kellgren-Lawrence grade (0 to 4). Severity of effusion and synovitis was graded 0 to 3 based on the Whole Organ Magnetic Resonance Imaging Score system. The associations of cysts and cyst-like bursitides and severity of radiographic OA, MRI-detected effusion and synovitis were analyzed using logistic regression controlling for clustering by person. The Wilcoxon signed-rank test was used to determine whether there was a significant change in the size of lesions between baseline and follow-up. RESULTS. At least one lesion (any type) was present in 222 (70%) knees. The most prevalent lesions were popliteal cysts (40%, 128/319), followed by subgastrocnemius bursitis (15%, 49/319) and proximal tibiofibular joint cysts (8%, 26/319). Bilateral lesions were seen in 49% of the subjects. Only popliteal cysts and subgastrocnemius bursitis showed a significant change in size (P < 0.001). No trend was observed between prevalence of any of the cyst-like lesions analyzed and the increasing radiographic OA severity. Increasing prevalence of subgastrocnemius bursitis was associated with increasing severity of effusion (P = 0.0072) and synovitis (P = 0.0033). CONCLUSIONS. None of the cyst-like lesions analyzed seems to be a marker of radiographic OA severity in knees with chronic frequent pain. Subgastrocnemius bursitis may be used as a marker of effusion/synovitis severity. Bilateral cyst-like lesions are relatively commonly observed in people with chronic knee pain.Item Preventive strategies and research for ultraviolet-associated cancer(National Institute of Environmental Health Sciences, 1995-11) Koh, H.K.Ultraviolet (UV)-associated cancer is the most common cancer in the United States. Approximately 90% of nonmelanoma skin cancer and 65% of melanoma are attributable to UV exposure and theoretically could be eliminated by primary prevention measures. Safe sun strategy includes use of sunscreens, use of protective clothing, minimization of exposure from 10 A.M. to 3 P.M., and avoidance of tanning parlors. Although more definitive data in human populations on the effectiveness of sunscreens to prevent melanoma and skin cancer are needed, sunscreens are thought to reduce risk. Safe sun prevention must start in childhood and adolescence when people receive most of their UV exposure. Secondary prevention through professional and public education and early detection may further reduce melanoma mortality.Item Cerebral Collateral Circulation in Carotid Artery Disease(Bentham Science Publishers Ltd., 2011-12-29) Romero, José R.; Pikula, Aleksandra; Nguyen, Thanh N.; Nien, Yih Lin; Norbash, Alexander; Babikian, Viken L.Carotid artery disease is common and increases the risk of stroke. However, there is wide variability on the severity of clinical manifestations of carotid disease, ranging from asymptomatic to fatal stroke. The collateral circulation has been recognized as an important aspect of cerebral circulation affecting the risk of stroke as well as other features of stroke presentation, such as stroke patterns in patients with carotid artery disease. The cerebral circulation attempts to maintain constant cerebral perfusion despite changes in systemic conditions, due to its ability to autoregulate blood flow. In case that one of the major cerebral arteries is compromised by occlusive disease, the cerebral collateral circulation plays an important role in preserving cerebral perfusion through enhanced recruitment of blood flow. With the advent of techniques that allow rapid evaluation of cerebral perfusion, the collateral circulation of the brain and its effectiveness may also be evaluated, allowing for prompt assessment of patients with acute stroke due to involvement of the carotid artery, and risk stratification of patients with carotid stenosis in chronic stages. Understanding the cerebral collateral circulation provides a basis for the future development of new diagnostic tools, risk stratification, predictive models and new therapeutic modalities. In the present review we discuss basic aspects of the cerebral collateral circulation, diagnostic methods to assess collateral circulation, and implications in occlusive carotid artery disease.Item Persistent Left Superior Vena Cava: A Case Report and Review of Literature(BioMed Central, 2008-10-10) Goyal, Sandeep K; Punnam, Sujeeth R; Verma, Gita; Ruberg, Frederick LPersistent left superior vena cava is rare but important congenital vascular anomaly. It results when the left superior cardinal vein caudal to the innominate vein fails to regress. It is most commonly observed in isolation but can be associated with other cardiovascular abnormalities including atrial septal defect, bicuspid aortic valve, coarctation of aorta, coronary sinus ostial atresia, and cor triatriatum. The presence of PLSVC can render access to the right side of heart challenging via the left subclavian approach, which is a common site of access utilized when placing pacemakers and Swan-Ganz catheters. Incidental notation of a dilated coronary sinus on echocardiography should raise the suspicion of PLSVC. The diagnosis should be confirmed by saline contrast echocardiography.