Cases of morbillivirus have been recorded in the Southern Hemisphere but have not been linked to significant marine mammal mortality. Post-mortems were conducted on 58 carcasses (44 Indo-Pacific ...bottlenose dolphins, two common bottlenose dolphins, 12 short-beaked common dolphins) from South Australia during 2005–2013, including an unusual mortality event (UME) in St Vincent Gulf Bioregion (SVG) during 2013. Diagnostic pathology, circumstance of death, body condition, age and stomach contents were documented for Indo-Pacific bottlenose dolphins. At least 50 dolphins died during the UME, 41 were Indo-Pacific bottlenose dolphins and most were young. The UME lasted about seven months and had two peaks, the first being the largest. Effect on the population is unknown. Diagnostic testing for morbillivirus was conducted on 57 carcasses, with evidence for infection in all species during 2011–2013. All tested UME bottlenose dolphins were positive for cetacean morbillivirus (CeMV), and the pathology included interstitial pneumonia, lymphoid depletion and syncytia. Concurrent pathologies, including lung parasite and fungal infections, and severe cutaneous bruising were observed in many dolphins. The event coincided with elevated water temperatures, a diatom bloom and significant fish die-offs. We conclude that the cause for the UME was multifactorial and that CeMV was a major contributor.
In 2013, South Australia experienced unusually high and variable water temperatures (5°C above the historic average), with a peak sea surface temperature of approximately 27°C over a wide geographic ...area covering both gulfs and shelf waters. Over the same period and similar geographic area, a prolonged and widespread marine mortality event occurred. From January to May 2013, low level rates of incidental morbidity and mortality of abalone (Haliotis rubra and H. laevigata) and at least 29 fish species were observed. Mortalities were geographically extensive from Port MacDonnell on the South Coast of South Australia to Point Drummond on Eyre Peninsula, and including two gulf systems, spanning approximately 2,900km of coastline. Mortalities were investigated using gross pathology, histopathology, bacterial culture and polymerase chain reaction (PCR) techniques. Water samples were collected to assess water column nutrient status and phytoplankton biomass levels and community composition. High nutrient concentrations were suggestive of high phytoplankton productivity, with conditions conducive to diatom blooms. A harmful (abrasive) diatom, Chaetoceros coarctatus, was observed in higher concentrations than the historical average. Observed fish mortalities were restricted to a small proportion of the populations and primarily comprised of temperate small-bodied benthic inshore species. Fish histopathology was suggestive of prolonged stress (melanomacrophage aggregation in spleens and kidneys), physical gill damage (focal gill lesions likely caused by C. coarctatus) and lethal bacterial septicaemia. Infectious and notifiable diseases were ruled out in all fish and abalone samples. Abalone mortalities were also restricted to a small proportion of the population with thermal stress a likely contributing factor that resulted in terminal secondary bacterial infections. A marine heatwave event, which promoted blooms of algae, including C. coarctatus, was likely the primary cause of widespread marine mortalities throughout South Australia in 2013. With marine heatwaves projected to increase in frequency, duration and spatial extent, this investigation demonstrated that most at risk will be temperate species in shallow water habitats already at their upper thermal tolerance limits, particularly those with high site fidelity. This should be considered in future climate proofing strategies, including risk and impact assessments underpinning the management of marine resources, fisheries, aquaculture and ecotourism.
Background: Several authors have used advanced magnetic resonance imaging (MRI) techniques to investigate whether patients with neuromyelitis optica (NMO) have occult damage in normal-appearing brain ...tissue, similarly to multiple sclerosis (MS). To date, the literature contains no data derived from the combined use of several advanced MRI techniques in the same NMO subjects.
Objective: We set out to determine whether occult damage could be detected in the normal-appearing brain tissue of a small group of patients with NMO using a multiparametric MRI approach.
Methods: Eight female patients affected by NMO (age range 44–58 years) and seven sex- and age-matched healthy controls were included. The techniques used on a 1.5 T MRI imaging scanner were magnetization transfer imaging, diffusion tensor imaging, tract-based spatial statistics, spectroscopy and voxel-based morphometry in order to analyse normal-appearing white matter and normal-appearing grey matter.
Results: Structural and metabolic parameters showed no abnormalities in normal-appearing white matter of patients with NMO. Conversely, tract-based spatial statistics demonstrated a selective alteration of the optic pathways and the lateral geniculate nuclei. Diffusion tensor imaging values in the normal-appearing grey matter were found to be significantly different in the patients with NMO versus the healthy controls. Moreover, voxel-based morphometry analysis demonstrated a significant density and volume reduction of the sensorimotor cortex and the visual cortex.
Conclusions: Our data disclosed occult structural damage in the brain of patients with NMO, predominantly involving regions connected with motor and visual systems. This damage seems to be the direct consequence of transsynaptic degeneration triggered by lesions of the optic nerve and spine.
MR imaging is essential for MS diagnosis and management, yet it has limitations in assessing axonal damage and remyelination. Gadolinium-based contrast agents add value by pinpointing acute ...inflammation and blood-brain barrier leakage, but with drawbacks in safety and cost. Neurite orientation dispersion and density imaging (NODDI) assesses microstructural features of neurites contributing to diffusion imaging signals. This approach may resolve the components of MS pathology, overcoming conventional MR imaging limitations.
Twenty-one subjects with MS underwent serial enhanced MRIs (12.6 ± 9 months apart) including NODDI, whose key metrics are the neurite density and orientation dispersion index. Twenty-one age- and sex-matched healthy controls underwent unenhanced MR imaging with the same protocol. Fifty-eight gadolinium-enhancing and non-gadolinium-enhancing lesions were semiautomatically segmented at baseline and follow-up. Normal-appearing WM masks were generated by subtracting lesions and dirty-appearing WM from the whole WM.
The orientation dispersion index was higher in gadolinium-enhancing compared with non-gadolinium-enhancing lesions; logistic regression indicated discrimination, with an area under the curve of 0.73. At follow-up, in the 58 previously enhancing lesions, we identified 2 subgroups based on the neurite density index change across time: Type 1 lesions showed increased neurite density values, whereas type 2 lesions showed decreased values. Type 1 lesions showed greater reduction in size with time compared with type 2 lesions.
NODDI is a promising tool with the potential to detect acute MS inflammation. The observed heterogeneity among lesions may correspond to gradients in severity and clinical recovery after the acute phase.
Background and purpose
Patients with a history of brain radiotherapy can experience acute stroke‐like syndromes related to the delayed effects of brain radiation, including stroke‐like migraine ...attacks after radiation therapy syndrome, peri‐ictal pseudoprogression and acute late‐onset encephalopathy after radiation therapy syndrome. The aim of this study was to collect evidence on the long‐term outcome and treatment of these conditions, whose knowledge is undermined by their rarity and fragmented description.
Methods
Cases were collected, both prospectively and retrospectively, amongst six neuro‐oncology departments. Inclusion criteria were as follows: (i) history of brain radiotherapy (completed at least 6 months before the acute episode); (ii) new onset of acute/subacute neurological symptoms; (iii) exclusion of all etiologies unrelated to brain irradiation. A review of current literature on stroke‐like syndromes was performed to corroborate our findings.
Results
Thirty‐two patients with acute neurological conditions attributed to the delayed effects of radiation were identified, including 26 patients with stroke‐like syndromes. Patients with stroke‐like syndromes commonly presented with a mosaic of symptoms, including focal deficits (77%), encephalopathy (50%), seizures (35%) and headache (35%). Seventy‐three percent of them had acute consistent magnetic resonance imaging alterations. Treatment included high‐dose steroids in 65% of cases. Twenty‐two patients recovered completely (85%). Sixteen patients (62%) experienced relapses (median follow‐up 3.5 years). A literature review identified 87 additional stroke‐like cases with similar characteristics.
Conclusions
Stroke‐like events related to brain irradiation may be associated with permanent sequelae. Steroids are often administered on empirical grounds, as they are thought to accelerate recovery. Relapses are common, highlighting the need to elaborate adequate prevention strategies.
Pompe disease is an autosomal recessive disorder in which deficiency of the lysosomal enzyme acid alpha-glucosidase results in the accumulation of glycogen mostly in muscle tissues. Several reports ...suggest a higher incidence of intracranial vascular abnormalities (IVAs) in this condition, as well as brain microbleeds and cerebral vasculopathy. The aim of our study was to evaluate through neuroimaging studies the incidence of these anomalies in our cohort of late-onset Pompe disease (LOPD) patients asymptomatic for cerebrovascular disease, looking for correlations with clinical and genetic data. We studied 18 LOPD patients with brain magnetic resonance angiography (MRA), or contrast-enhanced computed tomography (CECT). Diameters of individual arteries were measured and compared with average values as proposed in the literature. We found IVAs in 13 of the 18 patients, mostly dilatative arteriopathy affecting the vertebrobasilar system. The anterior circle was involved in seven of the 18 patients. The diameter of the basilar artery at 1 cm was found to correlate both with age (spearman rho,
p
= 0.037) and disease duration (
p
= 0.004), but no other statistically significant correlation was documented. The incidence of intracranial dilatative arteriopathy in LOPD was higher than in the general population, confirming the literature data. However, we did not find intracranial aneurysms microbleeds or significant cerebrovascular disease. Abnormalities in the anterior and the posterior circle of Willis correlated with age and disease duration, but not with the severity of muscle/respiratory involvement or with genetic data. Further studies in larger cohorts of patients are needed to confirm these findings.
Scientific debate over chronic cerebrospinal venous insufficiency (CCSVI) has drawn attention to venous system involvement in a series of pathologic brain conditions. In the last few decades, the MRI ...venography (MRV) field has developed a number of valuable sequences to better investigate structural anatomy, vessel patency, and flow characteristics of venous drainage in the intra- and extracranial systems. A brief two-tier protocol is proposed to encompass the study of intra- and extracranial venous drainage with and without contrast administration, respectively. Contrast-enhanced protocol is based on time-resolved contrast-enhanced MRV of the whole region plus extracranial flow quantification through 2D Cine phase contrast (PC); non-contrast-enhanced protocol includes intracranial 3D PC, extracranial 2D time of flight (TOF), and 2D Cine PC flow quantification. Total scanning time is reasonable for clinical applications: approximately seven minutes is allocated for the contrast protocol (most of which is due to 2D Cine PC), while the noncontrast protocol accounts for around twenty minutes. We believe that a short though exhaustive MRI scan of the whole intra- and extracranial venous drainage system can be valuable for a variety of pathologic conditions, given the possible venous implication in several neurological conditions.
A bibliographical search was conducted for papers published between 1999 and 2007 to verify the validity of International Classification of Headache Disorders (ICHD)-II criteria for the Tolosa-Hunt ...syndrome (THS) in terms of (i) the role of magnetic resonance imaging (MRI); (ii) which steroid treatment should be considered as adequate; and (iii) the response to treatment. Of 536 articles, 48, reporting on 62 patients, met the inclusion criteria. MRI was positive in 92.1% of the cases and it normalized after clinical resolution. There was no evidence of which steroid schedule should be considered as adequate; high-dose steroids are likely to be more effective both to induce resolution and to avoid recurrences. Pain subsided within the time limit required by the ICHD-II criteria, but signs did not. We conclude that THS diagnostic criteria can be improved on the basis of currently available data. MRI should play a pivotal role both to diagnose and to follow-up THS.
To assess the capability of computed tomography (CT) in the prediction of irreversible ischemic brain damage and its association with the clinical course within 6 hours of stroke onset.
Serial CT ...scans obtained within 6 hours of stroke onset, at 22-96 hours (median, 1 day), and at 2-36 days (median, 7 days) after symptom onset in 786 patients with ischemic stroke were prospectively studied, and follow-up CT scans were used as the reference. Clinical variables were assessed prospectively and independently of CT evaluation.
The specificity and positive predictive value of ischemic edema at baseline CT for brain infarcts were 85% (95% CI: 77%, 91%) and 96% (95% CI: 94%, 98%), respectively. Sensitivity and negative predictive values were 64% (95% CI: 60%, 67%) and 27% (95% CI: 23%, 32%), respectively. Patients without early CT findings were less severely affected (P<.001), developed smaller infarcts (P<.001), had fewer intracranial bleeding events (P<.001), and had a better clinical outcome at 90 days (P<.001) compared with patients with hypoattenuating brain tissue at early CT.
After ischemic stroke, x-ray hypoattenuation at CT is highly specific for irreversible ischemic brain damage if detection occurs within the first 6 hours. Patients without hypoattenuating brain tissue have a more favorable clinical course.
Background
Cognitive impairment is a common symptom of multiple sclerosis (MS), but the association between cognitive impairment and magnetic resonance imaging (MRI) disease measures in patients with ...relapsing–remitting (RR) MS is unclear.
Objectives
To study the prevalence of cognitive impairment and its relation with MRI disease measures in mildly disabled patients with RRMS.
Methods
Patients aged 18–50 years with RRMS (McDonald criteria) and an Expanded Disability Status Scale (EDSS) score ≤4.0, who were enrolled in the Cognitive Impairment in Multiple Sclerosis (COGIMUS) study, underwent baseline standardized MRI complete neurological examination and neuropsychological testing.
Results
A total of 550 patients were enrolled, 327 of whom underwent MRI assessments. Cognitive impairment (impaired performance in ≥3 cognitive tests) was present in approximately 20% of all patients and in the subgroup who underwent MRI. T2 hyperintense and T1 hypointense lesion volumes were significantly higher in patients with cognitive impairment (defined as impaired performance on at least three tests of the Rao’s battery) than those without. EDSS score was also significantly higher in cognitively impaired than in cognitively preserved patients. Disease duration, depression, and years in formal education did not differ significantly between cognitively impaired and cognitively preserved patients. T2 lesion volume, performance intelligence quotient, and age were significant predictors of cognitive impairment in this population. Weak correlations were found between performance on individual cognitive tests and specific MRI measures, with T1 and T2 lesion volumes correlating with performance on most cognitive tests.
Conclusions
Cognitive impairment occurs in approximately one-fifth of mildly disabled patients with MS and is associated with specific MRI disease measures. Assessment of cognitive function at diagnosis could facilitate the identification of patients who may benefit from therapeutic intervention with disease-modifying therapies to prevent further lesion development.
PDF
