Poster: ECR 2012 / C-2334 / MR imaging the post operative spine – What to expect! by: A. Jain 1, M. Paravasthu1, M. Bhojak1, K. Das2; 1Warrington/UK, 2Liverpool/UK
To investigate the agreement between manually and automatically generated tracts from diffusion tensor imaging (DTI) in patients with temporal lobe epilepsy (TLE). Whole and along-the-tract diffusivity metrics and correlations with patient clinical characteristics were analyzed with respect to tractography approach. We recruited 40 healthy controls and 24 patients with TLE who underwent conventional T1-weighted imaging and 60-direction DTI. An automated (Automated Fiber Quantification, AFQ) and manual (TrackVis) deterministic tractography approach was used to identify the uncinate fasciculus (UF) and parahippocampal white matter bundle (PHWM). Tract diffusion scalar metrics were analyzed with respect to agreement across automated and manual approaches (Dice Coefficient and Spearman correlations), to side of onset of epilepsy and patient clinical characteristics, including duration of epilepsy, age of onset and presence of hippocampal sclerosis. Across approaches the analysis of tract morphology similarity revealed Dice coefficients at moderate to good agreement (0.54 - 0.6) and significant correlations between diffusion values (Spearman's Rho=0.4–0.9). However, within bilateral PHWM, AFQ yielded significantly lower FA (left: Z = 4.4, p<0.001; right: Z = 5.1, p<0.001) and higher MD values (left: Z=-4.7, p<0.001; right: Z=-3.7, p<0.001) compared to the manual approach. Whole tract DTI metrics determined using AFQ were significantly correlated with patient characteristics, including age of epilepsy onset in FA (R = 0.6, p = 0.02) and MD of the ipsilateral PHWM (R=-0.6, p = 0.02), while duration of epilepsy corrected for age correlated with MD in ipsilateral PHWM (R = 0.7, p<0.01). Correlations between clinical metrics and diffusion values extracted using the manual whole tract technique did not survive correction for multiple comparisons. Both manual and automated along-the-tract analyses demonstrated significant correlations with patient clinical characteristics such as age of onset and epilepsy duration. The strongest and most widespread localized ipsi- and contralateral diffusivity alterations were observed in patients with left TLE and patients with HS compared to controls, while patients with right TLE and patients without HS did not show these strong effects. Manual and AFQ tractography approaches revealed significant correlations in the reconstruction of tract morphology and extracted whole and along-tract diffusivity values. However, as non-identical methods they differed in the respective yield of significant results across clinical correlations and group-wise statistics. Given the absence of excellent agreement between manual and AFQ techniques as demonstrated in the present study, caution should be considered when using AFQ particularly when used without reference to benchmark manual measures.
Highlights•We assessed the role of imaging in encephalitis.•We assessed the agreement between raters on scan interpretation.•Diagnosis for herpes simplex encephalitis (HSE) was good.•Agreement was worse for ADEM and other alternative aetiologies.•HSE can be dismissed if MRI normal 72 hours after neurological symptom onset (with negative CSF tests).AbstractAimTo assess the role of imaging in the early management of encephalitis and the agreement on findings in a well-defined cohort of suspected encephalitis cases enrolled in the Prospective Aetiological Study of Encephalitis conducted by the Health Protection Agency (now incorporated into Public Health England).Materials and methodsEighty-five CT examinations from 68 patients and 101 MRI examinations from 80 patients with suspected encephalitis were independently rated by three neuroradiologists blinded to patient and clinical details. The level of agreement on the interpretation of images was measured using the kappa statistic. The sensitivity, specificity, and negative and positive predictive values of CT and MRI for herpes simplex virus (HSV) encephalitis and acute disseminated encephalomyelitis (ADEM) were estimated.ResultsThe kappa value for interobserver agreement on rating the scans as normal or abnormal was good (0.65) for CT and moderate (0.59) for MRI. Agreement for HSV encephalitis was very good for CT (0.87) and MRI (0.82), but only fair for ADEM (0.32 CT; 0.31 MRI). Similarly, the overall sensitivity of imaging for HSV encephalitis was ∼80% for both CT and MRI, whereas for ADEM it was 0% for CT and 20% for MRI. MRI specificity for HSV encephalitis between 3–10 days after symptom onset was 100%.ConclusionThere is a subjective component to scan interpretation that can have important implications for the clinical management of encephalitis cases. Neuroradiologists were good at diagnosing HSV encephalitis; however, agreement was worse for ADEM and other alternative aetiologies. Findings highlight the importance of a comprehensive and multidisciplinary approach to diagnosing the cause of encephalitis that takes into account individual clinical, microbiological, and radiological features of each patient.
Objective: To identify the natural history of non-MS optico-spinal demyelination.
Background: Patients with non-MS ‘demyelination’ can be challenging to classify. With the availability of Aquaporin-4 antibody testing, many patients with relapsing spinal cord and optic nerve syndromes can be classified as NMO spectrum disorders. Despite this, a number of patients remain who have ‘isolated optico-spinal demyelination’ whose natural history is uncertain.
Methods: This is a prospective longitudinal cohort study. From 2003 to 2005 cases of non-MS optico-spinal demyelination (defined in 2003 as optic neuritis, myelitis (any lesion length) and brain MRI not suggestive of MS) were reported via the British Neurological Surveillance Unit (n= 128). Some were typical for NMO and MS (n=61) as per criteria in 2005. After excluding these, 67 patients were classified as optico-spinal demyelination - unclassified (OSD-U) (52[percnt]). Patients and their physicians were contacted in 2011 and 2015 to ascertain most recent diagnosis. AQP4 antibodies were tested in all.
Results: By 2015 (10 years follow up) outcomes of 64 of the 67 patients were obtained. A definite diagnosis was made based on clinical, radiological or serum AQP4 IgG in 50 (75[percnt]) patients. 39 were classified as NMOSD (58[percnt]), 11as MS (17[percnt]) 14 remained as OSD-U (21 [percnt]). 3 (4[percnt]) patients were untraceable. 7 of the 14 OSD -U are being treated with azathioprine, one with Rebif and 6 are not on treatment.
Conclusions: At 10 years from recruitment into study and a median of 12 years after onset of disease 75[percnt] of unclassifiable optico-spinal demyelinating disorders had a definite diagnosis. 17[percnt] developed MS and 58[percnt] developed NMOSD. 21[percnt] still remained unclassifiable. Whether the last group comprise a distinct disease entity or will turn out to be typical MS or NMOSD (perhaps associated with new serum markers) on longer follow up remains to be seen. Disclosure: Dr. Hamid has nothing to disclose. Dr. Panicker has nothing to disclose. Dr. Elsone has nothing to disclose. Dr. Mutch has nothing to disclose. Dr. Das has nothing to disclose. Dr. Boggild has nothing to disclose. Dr. Jacob has nothing to disclose.
Most techniques used for automatic segmentation of subcortical brain regions are developed for three-dimensional (3D) MR images. MRIs obtained in non-specialist hospitals may be non-isotropic and two-dimensional (2D). Automatic segmentation of 2D images may be challenging and represents a lost opportunity to perform quantitative image analysis. We determine the performance of a modified subcortical segmentation technique applied to 2D images in patients with idiopathic generalised epilepsy (IGE).Volume estimates were derived from 2D (0.4 × 0.4 × 3 mm) and 3D (1 × 1x1mm) T1-weighted acquisitions in 31 patients with IGE and 39 healthy controls. 2D image segmentation was performed using a modified FSL FIRST (FMRIB Integrated Registration and Segmentation Tool) pipeline requiring additional image reorientation, cropping, interpolation and brain extraction prior to conventional FIRST segmentation. Consistency between segmentations was assessed using Dice coefficients and volumes across both approaches were compared between patients and controls. The influence of slice thickness on consistency was further assessed using 2D images with slice thickness increased to 6 mm.All average Dice coefficients showed excellent agreement between 2 and 3D images across subcortical structures (0.86-0.96). Most 2D volumes were consistently slightly lower compared to 3D volumes. 2D images with increased slice thickness showed lower agreement with 3D images with lower Dice coefficients (0.55-0.83). Significant volume reduction of the left and right thalamus and putamen was observed in patients relative to controls across 2D and 3D images.Automated subcortical volume estimation of 2D images with a resolution of 0.4 × 0.4x3mm using a modified FIRST pipeline is consistent with volumes derived from 3D images, although this consistency decreases with an increased slice thickness. Thalamic and putamen atrophy has previously been reported in patients with IGE. Automated subcortical volume estimation from 2D images is feasible and most reliable at using in-plane acquisitions greater than 1 mm x 1 mm and provides an opportunity to perform quantitative image analysis studies in clinical trials.
Cranial diabetes insipidus (CDI) is the deficiency of vasopressin.CDI is rarely resulted from a pituitary stalk lesion; these cases represent a clinical conundrum due to the differing clinical presentations and aetiologies.We present a series of three cases of CDI arising from pituitary stalk lesions/thickenings that highlight both the symptomatic features and multiple aetiologies of this condition.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)