Prospective Comparison of T1-SPACE and MPRAGE for the Identification of Intrinsic T1 Hyperintensity in Patients with Intracranial Melanoma Metastases.

BACKGROUND AND PURPOSE: Volumetric TSE (3D-TSE) techniques are increasingly replacing volumetric magnetization-prepared gradient recalled-echo (3D-GRE) sequences due to improved metastasis detection. In addition to providing a baseline for assessing postcontrast enhancement, precontrast T1WI also identifies intrinsic T1 hyperintensity, for example, reflecting melanin or blood products. The ability of precontrast 3D-TSE to demonstrate intrinsic T1 hyperintensity is not clear from the literature; thus, this study compares precontrast 3D-TSE and 3D-GRE sequences for identifying intrinsic T1 hyperintensity in patients with metastatic melanoma. MATERIALS AND METHODS: Patients with metastatic melanoma and previously reported intrinsic T1 hyperintensity were identified. MRIs were performed at 3T including both 3D-GRE (MPRAGE) and 3D-TSE T1 sampling perfection with application-optimized contrasts by using different flip angle evolution (T1-SPACE) sequences precontrast. Axial 1-mm slices of both T1WI sequences were independently reviewed by 2 neuroradiologists, comparing the conspicuity of each lesion between the 2 sequences according to a 5-point scale and assessing whether the intrinsic T1 hyperintensity was attributable to melanin, blood products, or both. RESULTS: Twenty examinations were performed, with a total of 214 lesions demonstrating intrinsic T1 hyperintensity. Both readers found that intrinsic T1 hyperintensity was less conspicuous with T1-SPACE compared with MPRAGE for most lesions assessed (81.8%, averaged across both readers), including for lesions with intrinsic T1 hyperintensity attributable to melanin and blood products. Intrinsic T1 hyperintensity was rarely more conspicuous on T1-SPACE (1.4%). CONCLUSIONS: Precontrast intrinsic T1 hyperintensity is more conspicuous with MPRAGE than T1-SPACE. In patients with metastatic melanoma, 3D-GRE should be preferred as the precontrast T1WI sequence when both 3D-TSE and 3D-GRE are performed postcontrast and when not administering IV contrast.

Persistent median artery on computed tomographic arteriovenous fistulograms in patients on haemodialysis.

INTRODUCTION: Cadaveric studies suggest an increasing prevalence of the persistent median artery (PMA) over a prolonged timeframe. The aim of this retrospective cross-sectional study was to evaluate the PMA prevalence in haemodialysis patients who had computed tomographic fistulograms (CTFs), and if present, their calibres and origins. METHODS: All consecutive adult patients referred for an upper limb CTFs for assessment of arteriovenous fistula (AVF) dysfunction from 2006 to 2021 were included. Patients whose CTF did not include the forearm were excluded. PMA was identified as an artery running alongside the median nerve between flexor digitorum superficialis and flexor digitorum profundus. Patient demographics, presence of PMA including size and origin were recorded. RESULTS: A PMA was found in 91/170 (53.5%) CTFs (7:3 male-to-female ratio, mean age 71-years). When stratified by age, prevalence increased with decreasing age; 51% in >70-year-olds, 54% in 50-70-year-olds and 67% in <50-year-olds. The average PMA diameter was 2.2 mm proximally and 1.8 mm distally. No stenosis was observed in the PMAs. CONCLUSION: The PMA prevalence appears to increase with decreasing age and is a frequently encountered anatomical variant. Radiologists assessing forearm vasculature need to be aware of this anatomical variant and potentially include it in their future reports. Further research into the PMA may make its potential use as arterial conduits for AVF, potential donor grafts for coronary artery bypass surgery or additional vascular access options possible. Whether the reducing prevalence with age reflects an overall increasing prevalence is yet to be determined.

Improving the diagnosis of radiation necrosis after stereotactic radiosurgery to intracranial metastases with conventional MRI features: a case series.

BACKGROUND: The distinction between true disease progression and radiation necrosis after stereotactic radiosurgery to intracranial metastases is a common, but challenging, clinical scenario. Improvements in systemic therapies are increasing the importance of this distinction. A variety of imaging techniques have been investigated, but the value of any individual technique is limited. CASE PRESENTATION: Assessment should extend beyond simply the appearances of the lesion at a given timepoint, but also consider local anatomy and lesion evolution. Firstly, enlargement of a metastasis is affected by local anatomical boundaries, such as the dural reflections or cerebrospinal fluid spaces. In contrast, the radiation dose administered with stereotactic radiosurgery does not respect these anatomical boundaries and is largely concentric around the treated lesion. Therefore, new, non-contiguous enhancement across such a boundary can be confidently attributed to radiation necrosis. Secondly, the dynamic nature of radiation necrosis may result in a change in lesion shape, with different portions of the lesion simultaneously enlarging and regressing. Regression of part of a lesion indicates radiation necrosis, even if the overall lesion enlarges. This case series describes these two features and provides illustrative clinical examples in which these features allowed a confident diagnosis of radiation necrosis. CONCLUSIONS: The distinction between true disease progression and radiation necrosis should extend beyond just the appearances of the lesion. More nuanced interpretation incorporating a relationship to anatomical boundaries and a change in shape can improve accurate diagnosis of radiation necrosis.

Error and cognitive bias in diagnostic radiology.

Errors in diagnostic radiology are not infrequent. Patient harm related to these errors is however less common and may be avoided via various preventative mechanisms within the medical system including, but not limited to, multidisciplinary meetings, second opinions, subspecialty expertise and clinician experience. Failure at a number of points in the system is often required to result in patient harm. Radiologists, and in particular departmental leaders, should proactively address the known underlying root causes of diagnostic errors and cognitive biases, ensure systems are in place to promptly discover and control unmitigated root causes as they arise and ensure an unbiased 'blameless' or 'just' culture of error investigation and proces sing including the implementation of non-punitive peer feedback and peer learning. This article provides an overview of errors in diagnostic radiology including the causes and potential ramifications and how we might reduce their frequency and impact.

Relationship Between Interpersonal Depressive Symptoms and Reduced Amygdala Volume in People with Multiple Sclerosis: Considerations for Clinical Practice.

BACKGROUND: The lifetime prevalence of depression in people with multiple sclerosis (MS) is approximately 50% compared with around 15% in the general population. There is a relationship between depression and quality of life in people with MS and evidence that depression may contribute to disease progression. METHODS: This cross-sectional pilot study assessed the association between depression and regional brain atrophy, including amygdala and hippocampal volume. Forty-nine participants with MS recruited through a hospital MS clinic were administered the Center for Epidemiological Studies Depression Scale Revised (CESD-R) to investigate whether higher endorsements on the items depressive affect and interpersonal symptoms were associated with volumetric magnetic resonance imaging measurements of hippocampal and amygdala atrophy. RESULTS: Regression analysis revealed an association between depression-related interpersonal symptoms and right amygdala volume. No association was found between depression and hippocampal volume. CONCLUSIONS: These results provide preliminary support for a unilateral, biologically based relationship between the right amygdala and characteristic interpersonal depressive symptoms expressed by people with MS and add to the growing body of literature implicating regional brain atrophy in MS-associated depression. Given that the interpersonal subcomponent of the CESD-R measures social functioning, and the neural networks in the amygdala are known to be implicated in processing social stimuli, this research suggests that targeted diagnosis and treatments for depression in people with MS may be particularly beneficial. Further confirmatory research of this relationship is required.

Detection of multiple sclerosis lesions in the cervical cord: which of the MAGNIMS 'mandatory' non-gadolinium enhanced sagittal sequences is optimal at 3T?

BACKGROUND AND PURPOSE: The magnetic resonance imaging in multiple sclerosis consensus guidelines currently mandate three sagittal non-contrast enhanced sequences of T2-weighted fast spin echo, proton density-weighted fast spin echo and short tau inversion recovery; however, these particular three sequences have not previously been compared at 3T. This study compared T2-weighted fast spin echo, proton density-weighted fast spin echo, short tau inversion recovery as well as the double inversion recovery sequence for the sagittal detection of multiple sclerosis lesions in the cervical spinal cord at 3T. METHODS: Nineteen multiple sclerosis patients underwent magnetic resonance imaging with 3T sagittal T2-weighted fast spin echo, proton density-weighted fast spin echo, short tau inversion recovery and double inversion recovery between November 2012 and April 2013. Two neuroradiologists independently reviewed the images, and the number of lesions detected on each sequence was recorded. Lesion conspicuity was quantitatively assessed with the lesion-to-cord-contrast ratio and lesion contrast-to-noise ratio. The Wilcoxon signed rank test was performed for statistical analysis. RESULTS: Proton density-weighted fast spin echo and short tau inversion recovery detected 32% more lesions compared to T2-weighted fast spin echo, and 37% more lesions compared to double inversion recovery. The lesion-to-cord-contrast ratio was highest in short tau inversion recovery, while the lesion contrast-to-noise ratio was highest for proton density-weighted fast spin echo. CONCLUSIONS: This study provides the necessary evidentiary support at 3T for the magnetic resonance imaging in multiple sclerosis spinal magnetic resonance imaging protocol consensus guidelines. At 3T sagittal proton density-weighted fast spin echo and short tau inversion recovery sequences allowed improved detection of cervical spinal cord multiple sclerosis lesions, compared to T2-weighted fast spin echo and three-dimensional double inversion recovery magnetic resonance imaging. Utilising T2-weighted fast spin echo alone at 3T is insufficient for lesion detection.

When should we image our patients? Appropriate use of imaging in inpatient psychiatry.

OBJECTIVE: Injudicious use of medical imaging may be associated with harm to patients and increased downstream healthcare costs. Guidance on the use of imaging in common psychiatric inpatient scenarios is inconsistent or absent. This paper explores three common clinical scenarios facing adult psychiatrists and provides guidance about the appropriate use of imaging. CONCLUSION: Psychiatrists and their junior colleagues would benefit from considering both pre- and post-test probability in each presentation.

The clinical utility of structural neuroimaging in first-episode psychosis: A systematic review.

BACKGROUND: Australian and US guidelines recommend routine brain imaging, either computed tomography or magnetic resonance imaging, to exclude structural lesions in presentations for first-episode psychosis. The aim of this review was to examine the evidence for the appropriateness and clinical utility of this recommendation by assessing the frequency of abnormal radiological findings in computed tomography and magnetic resonance imaging scans among patients with first-episode psychosis. METHODS: PubMed and Embase database were searched from inception to April 2018 using appropriate MeSH or Emtree terms. Studies were included in the review if they reported data on computed tomography or magnetic resonance imaging scan findings of individuals with first-episode psychosis. No restriction on the geographical location of the study or the age of participants was applied. We calculated the percentage of abnormal radiological findings in each study, separately by the two diagnostic methods. RESULTS: There were 16 suitable studies published between 1988 and 2017, reporting data on an overall 2312 patients with first-episode psychosis. Most were observational studies with a retrospective design and the majority examined patients with computed tomography. While structural abnormalities were a relatively common finding, these rarely required clinical intervention (range across studies: 0-60.7%; median: 3.5%) and were very rarely the cause of the psychotic symptoms (range: 0-3.3%; median: 0%). Only 2 of the 16 studies concluded that brain imaging should be routinely ordered in first-episode psychosis. CONCLUSION: There is insufficient evidence to suggest that brain imaging should be routinely ordered for patients presenting with first-episode psychosis without associated neurological or cognitive impairment. The appropriate screening procedure for structural brain lesions is conventional history-taking, mental status and neurological examination. If intracranial pathology is suspected clinically, a magnetic resonance imaging or computed tomography scan should be performed depending on the clinical signs, the acuity and the suspected pathology. National guidelines should reflect evidence-based data.

Neuroprotective Benefits of Antidepressants in Multiple Sclerosis: Are We Missing the Mark?

The potential of antidepressant medication to have a neuroprotective effect for people with multiple sclerosis (MS) has received increased interest in recent years. The possibility of antidepressants, particularly fluoxetine, for potential repurposing to treat primary progressive and secondary progressive MS is of interest as a result of the relative lack of disease-modifying medications for these subtypes. A number of animal studies have found positive results for a neuroprotective effect of antidepressant use in MS, with human studies showing mixed results. These human studies all have a significant limitation: they exclude people with moderate to severe depressive symptoms, a core symptom of MS beyond that of reactive depression. It is likely that reregulation of the common mechanisms in depression and MS, such as inflammation, serotonin, norepinephrine, glutamate and brain-derived neurotropic factor disruption, and hypothalamic-pituitary-thalamic axis dysregulation, are important to the neuroprotective value of antidepressant medication. Given that MS is known for its heterogeneity, the question might be less about whether antidepressant medication provides neuroprotective benefits to people with multiple sclerosis but for whom they provide benefits and whether we are designing studies that will detect a benefit. To answer these questions, studies must include people with MS and depressive symptoms as well as people with relapsing remitting and chronic subtypes.

Morphologic patterns of noncontrast-enhancing tumor in glioblastoma correlate with IDH1 mutation status and patient survival.

Glioblastomas with a substantial proportion of noncontrast-enhancing tumour (nCET) have a variety of imaging appearances. We aimed to determine whether glioblastomas demonstrating a substantial proportion (>33%) of nCET can be sub-classified by different morphologic pattern of nCET. We then assessed whether this improves the ability of MRI to predict isocitrate dehydrogenase-1 (IDH1) mutation status and whether this has prognostic significance independent of IDH1 mutation status. Pre-operative MRIs of patients with a new diagnosis of glioblastoma were reviewed. Tumours with >33% nCET were sub-classified by the dominant morphologic pattern of nCET: mass-like expansion, white matter dissemination, grey matter dissemination or a combination. IDH1 mutation status (by immunohistochemistry) and survival were compared for each pattern. 153 patients met the inclusion criteria, of whom 34 patients demonstrated >33% nCET. 10 patients had a significant mass-like component, either as the dominant pattern (n=4) or as part of a mixed pattern (n=6). The 10 patients with a significant mass-like component had longer survival than those without (median 387days, compared to 241days), though this was not statistically significant (p=0.242). Three patients had R132H-IDH1 mutations and >33% nCET, and all three had a mass-like component. Using the presence of a mass-like component of nCET for predicting IDH1 mutation status improved the positive predictive value, specificity and overall accuracy of MRI. Classification of nCET by morphologic pattern improves the ability of MRI to predict IDH1 mutations and may provide useful prognostic information.

Arytenoid cartilage movements are hypokinetic in Parkinson's disease: A quantitative dynamic computerised tomographic study.

BACKGROUND: Voice change is one of the earliest features of Parkinson's disease. However, quantitative studies of vocal fold dynamics which are needed to provide insight into disease biology, aid diagnosis, or track progression, are few. METHODS: We therefore quantified arytenoid cartilage movements and glottic area during repeated phonation in 15 patients with Parkinson's disease (symptom duration < 6 years) and 19 controls, with 320-slice computerised tomography (CT). We related these measures to perceptual voice evaluations and spirometry. We hypothesised that Parkinson's disease patients have a smaller inter-arytenoid distance, a preserved or larger glottic area because vocal cord bowing has previously been reported, less variability in loudness, more voice dysdiadochokinesis and breathiness and a shortened phonation time because of arytenoid hypokinesis relative to glottic area. RESULTS: Inter-arytenoid distance in Parkinson's disease patients was moderately smaller (Mdn = 0.106, IQR = 0.091-0.116) than in controls (Mdn = 0.132, IQR = 0.116-0.166) (W = 212, P = 0.015, r = -0.42), normalised for anatomical and other inter-subject variance, analysed with two-tailed Wilcoxon's rank sum test. This finding was confirmed in a linear mixed model analysis-Parkinson's disease significantly predicted a reduction in the dependent variable, inter-arytenoid distance (b = -0.87, SEb = 0.39, 95% CI [-1.66, -0.08], t(31) = -2.24, P = 0.032). There was no difference in glottic area. On perceptual voice evaluation, patients had more breathiness and dysdiadochokinesis, a shorter maximum phonation time, and less variability in loudness than controls. There was no difference in spirometry after adjustment for smoking history. CONCLUSIONS: As predicted, vocal fold adduction movements are reduced in Parkinson's disease on repeated phonation but glottic area is maintained. Some perceptual characteristics of Parkinsonian speech reflect these changes. We are the first to use 320-slice CT to study laryngeal motion. Our findings indicate how Parkinson's disease affects intrinsic laryngeal muscle position and excursion.

Diffusion and Perfusion MR Imaging in Acute Stroke: Clinical Utility and Potential Limitations for Treatment Selection.

Magnetic resonance (MR) diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) offer unique insight into acute ischemic stroke pathophysiology. These techniques may offer the ability to apply pathophysiology to accurately individualize acute stroke reperfusion treatment, including extending the opportunity of reperfusion treatment to well beyond the current time-based treatment windows.This review examines the use of DWI and PWI in the major stroke trials, their current clinical utility, and potential limitations for reperfusion treatment selection. DWI and PWI continue to be investigated in ongoing randomized controlled trials, and continued research into these techniques will help achieve the goal of tissue-based decision making and individualized acute stroke treatment.

Reliability of noncontrast-enhancing tumor as a biomarker of IDH1 mutation status in glioblastoma.

Isocitrate dehydrogenase 1 (IDH1) mutations in gliomas have been associated with a frontal lobe location and a greater proportion of noncontrast-enhancing tumour (nCET). The purpose of our study was to validate the utility of MRI imaging features in predicting IDH1 mutations in glioblastomas. Pre-operative MRIs of new glioblastoma patients, consisting of at least FLAIR and T1-weighted post-contrast sequences, were reviewed by a neuroradiologist based primarily on the VASARI feature set. IDH1 mutation testing was performed on all patients using immunohistochemistry. 153 patients met the inclusion criteria, of whom five had IDH1 mutations (3.3%). A frontal lobe location had equivalent frequency in both the IDH1-mutated and IDH1-wildtype cohorts (p=1.000). Three (60%) of the IDH1-mutated tumours had >33% nCET, compared to 21% of IDH1-wildtype (p=0.073). 12 tumours had a frontal lobe epicentre and >33% nCET, all being IDH1-wildtype. All five IDH1-mutated tumours had either a frontal lobe epicentre or >33% nCET, but none had both these features. Our results question the strength of the association between frontal lobe glioblastomas with substantial nCET and IDH1 mutations, as these features are also relatively frequent in IDH1-wildtype tumours, which are much more common. MRI is thus more useful for ruling out an IDH1 mutation rather than strongly suggesting its presence: if a particular glioblastoma does not have a frontal lobe epicentre and has less than 33% nCET, it can be predicted to be IDH1-wildtype with a high degree of confidence.

The incidence and significance of multicentric noncontrast-enhancing lesions distant from a histologically-proven glioblastoma.

Improvements in imaging are increasing the detection of multiple lesions in the setting of glioblastoma. Occasionally distant non-enhancing lesions may be identified which have the appearances of a multicentric low-grade glioma. We aimed to determine the incidence, prognostic significance and diagnostic value of this appearance in new glioblastoma patients. Pre-operative MRIs of patients with a new diagnosis of glioblastoma were reviewed to identify multicentric non-enhancing lesions, defined as areas of FLAIR hyperintensity and mass effect, without post-contrast enhancement, separate from the histologically-proven glioblastoma. Patient survival was compared to glioblastoma patients without these appearances, and follow-up imaging was reviewed. Nine of 151 patients (6 %) had multicentric non-enhancing lesions. Their median survival of 183 days was significantly worse than the 278 days for patients without multicentric nonenhancing lesions (p = 0.025). Follow-up MRIs were performed in four patients. In one patient, there were several additional lesions, one of which developed evidence of necrosis within 22 days of presentation. In the other three patients, the multicentric lesions developed enhancement and evidence of necrosis within 1 year, and became confluent on FLAIR with the dominant lesion. The appearance of a multicentric non-enhancing lesion is an uncommon finding in glioblastoma, but a poor prognostic feature. These lesions progress faster than expected for a low-grade glioma and are thus likely to represent more advanced lesions than their appearances suggest. Confluence with the dominant lesion developing with time suggests that the tumor is more extensive than appreciated on imaging.

Multifocal and multicentric glioblastoma: Improved characterisation with FLAIR imaging and prognostic implications.

Glioblastoma usually presents on imaging as a single peripherally enhancing lesion, but multiple enhancing lesions can occur, termed multifocal if there is a connection between enhancing lesions, or multicentric when no communication is demonstrated. We aim to determine the incidence and prognostic implications of multifocal and multicentric glioblastoma in the era of modern MRI, focusing on the added benefit of T2-weighted fluid-attenuated inversion recovery (FLAIR) imaging. Patients with a new diagnosis of glioblastoma were identified. Preoperative MRI were reviewed to determine whether more than one distinct enhancing lesion was present, and whether there was communication between lesions. The findings were compared against survival data. More than one discrete contrast-enhancing lesion was present in 51 of the 151 patients (34%). Communication between lesions was identified in 47 of these, most commonly direct parenchymal spread (41 patients). The patients with multiple lesions had worse survival (median 176days, compared to 346days), but this difference was not statistically significant (p=0.253). These tumours more frequently involved deep structures (p<0.001) and the posterior fossa (p=0.045), both of which were associated with worse survival. The presence of multiple enhancing foci in glioblastoma is common, occurring in about one-third of patients, and the majority have multifocal disease. The FLAIR sequence is the crucial sequence for demonstrating a communication between lesions. The worse survival of these patients is, at least in large part related to more extensive tumour dissemination and more frequent involvement of key structures, rather than multiplicity per se.

Incidence and prognostic significance of non-enhancing cortical signal abnormality in glioblastoma.

INTRODUCTION: The presence of non-enhancing cortical signal abnormality is useful for differentiating between glioblastoma and metastatic disease, but its significance has not been studied. We aimed to determine the incidence and prognostic implications of non-enhancing cortical signal abnormality in glioblastomas. METHODS: Patients with a new diagnosis of glioblastoma between September 2007 and December 2010 were identified. Only patients with at least fluid-attenuated inversion recovery (FLAIR) and post-contrast T1-weighted sequences were included. Pre-operative MRIs were reviewed together by two readers to determine whether there was evidence of non-enhancing cortical signal abnormality, based primarily on the FLAIR sequence. The results were compared with patient survival using both univariate and multivariate analysis. RESULTS: One hundred fifty-one patients met the inclusion criteria. Seventy-seven patients (51%) had evidence of non-enhancing cortical signal abnormality. On both univariate and multivariate analysis, there was overall no significant difference in survival between patients with non-enhancing cortical signal abnormality and those without. Peripheral enhancing lesions (51 patients) were generally associated with the longest survival, but subgroup analysis suggested that non-enhancing signal abnormality was associated with worse survival in these patients (P = 0.004), conveying an intermediate prognosis. CONCLUSIONS: Non-enhancing cortical signal abnormality is a common feature of glioblastomas, occurring in about half of cases. It does not affect survival overall, but appears to be associated with worse survival in the setting of a peripherally located enhancing lesion. This has the potential to alter surgical management.