Form and function of the intervertebral disc in health and disease: a morphological and stain comparison study.

Multiple histologic measurements are commonly used to assess degenerative changes in intervertebral disc (IVD) structure; however, there is no consensus on which stains offer the clearest visualization of specific areas within the IVD. The objective of this study was to compare multiple tinctorial stains, evaluate their ability to highlight structural features within the IVD, and investigate how they influence the capacity to implement a degeneration scoring system. Lumbar IVDs from seven human autopsy specimens were stained using six commonly used stains (Hematoxylin/Eosin, Toluidine Blue, Safranin-O/Fast Green, Extended FAST, modified Gomori's Trichrome, and Picrosirius Red Alcian Blue). All IVDs were evaluated by three separate graders to independently determine which stains (i) were most effective at discerning different structural features within different regions of the IVDs and (ii) allowed for the most reproducible assessment of degeneration grade, as assessed via the Rutges histological scoring system (Rutges et al. A validated new histological classification for intervertebral disc degeneration. Osteoarthritis Cartilage, 21, 2039-47). Although Trichrome, XFAST and PR/AB stains were all effective at highlighting different regions of whole IVDs, we recommend the use of PR/AB because it had the highest degree of rater agreement on assigned degeneration grade, allowed greater resolution of degeneration grade, has an inferential relationship between color and composition, and allowed clear differentiation of the different regions and structural disruptions within the IVD. The use of a standard set of stains together with a histological grading scheme can aid in the characterization of structural changes in different regions of the IVD and may simplify comparisons across the field. This collection of human IVD histological images highlights how IVD degeneration is not a single disease but a composite of multiple processes such as aging, injury, repair, and disease, each of which are unique to the individual.

[How to prepare an oral presentation and a conference]. / ¿Cómo preparar una comunicación oral y una conferencia?

The final aim of any scientific presentation is to transmit information clearly and effectively in a way that enables the members of the audience to assimilate it but also stimulates their intellects. The success of an oral presentation depends not only on the content of the presentation, but also on the speaker's skills in transmitting the information and making it attractive. To rise to the challenge posed by these objectives, presenters must work through different preparatory phases such as identifying the aims of the talk, preparing the contents of the talk, designing the presentation, and rehearsing the talk. This special article provides some useful recommendations for successful scientific presentations. It is intended for both new and experienced presenters.

MR Perfusion to Determine the Status of Collaterals in Patients with Acute Ischemic Stroke: A Look Beyond Time Maps.

BACKGROUND AND PURPOSE: Patients with acute stroke with robust collateral flow have better clinical outcomes and may benefit from endovascular treatment throughout an extended time window. Using a multiparametric approach, we aimed to identify MR perfusion parameters that can represent the extent of collaterals, approximating DSA. MATERIALS AND METHODS: Patients with anterior circulation proximal arterial occlusion who had baseline MR perfusion and DSA were evaluated. The volume of arterial tissue delay (ATD) at thresholds of 2-6 seconds (ATD2-6 seconds) and >6 seconds (ATD>6 seconds) in addition to corresponding values of normalized CBV and CBF was calculated using VOI analysis. The association of MR perfusion parameters and the status of collaterals on DSA were assessed by multivariate analyses. Receiver operating characteristic analysis was performed. RESULTS: Of 108 patients reviewed, 39 met our inclusion criteria. On DSA, 22/39 (56%) patients had good collaterals. Patients with good collaterals had significantly smaller baseline and final infarct volumes, smaller volumes of severe hypoperfusion (ATD>6 seconds), larger volumes of moderate hypoperfusion (ATD2-6 seconds), and higher relative CBF and relative CBV values than patients with insufficient collaterals. Combining the 2 parameters into a Perfusion Collateral Index (volume of ATD2-6 seconds × relative CBV2-6 seconds) yielded the highest accuracy for predicting collateral status: At a threshold of 61.7, this index identified 15/17 (88%) patients with insufficient collaterals and 22/22 (100%) patients with good collaterals, for an overall accuracy of 94.1%. CONCLUSIONS: The Perfusion Collateral Index can predict the baseline collateral status with 94% diagnostic accuracy compared with DSA.

Synthetic MRI for Clinical Neuroimaging: Results of the Magnetic Resonance Image Compilation (MAGiC) Prospective, Multicenter, Multireader Trial.

BACKGROUND AND PURPOSE: Synthetic MR imaging enables reconstruction of various image contrasts from 1 scan, reducing scan times and potentially providing novel information. This study is the first large, prospective comparison of synthetic-versus-conventional MR imaging for routine neuroimaging. MATERIALS AND METHODS: A prospective multireader, multicase noninferiority trial of 1526 images read by 7 blinded neuroradiologists was performed with prospectively acquired synthetic and conventional brain MR imaging case-control pairs from 109 subjects (mean, 53.0 ± 18.5 years of age; range, 19-89 years of age) with neuroimaging indications. Each case included conventional T1- and T2-weighted, T1 and T2 FLAIR, and STIR and/or proton density and synthetic reconstructions from multiple-dynamic multiple-echo imaging. Images were randomized and independently assessed for diagnostic quality, morphologic legibility, radiologic findings indicative of diagnosis, and artifacts. RESULTS: Clinical MR imaging studies revealed 46 healthy and 63 pathologic cases. Overall diagnostic quality of synthetic MR images was noninferior to conventional imaging on a 5-level Likert scale (P < .001; mean synthetic-conventional, -0.335 ± 0.352; Δ = 0.5; lower limit of the 95% CI, -0.402). Legibility of synthetic and conventional morphology agreed in >95%, except in the posterior limb of the internal capsule for T1, T1 FLAIR, and proton-density views (all, >80%). Synthetic T2 FLAIR had more pronounced artifacts, including +24.1% of cases with flow artifacts and +17.6% cases with white noise artifacts. CONCLUSIONS: Overall synthetic MR imaging quality was similar to that of conventional proton-density, STIR, and T1- and T2-weighted contrast views across neurologic conditions. While artifacts were more common in synthetic T2 FLAIR, these were readily recognizable and did not mimic pathology but could necessitate additional conventional T2 FLAIR to confirm the diagnosis.

Ultra-High-Field MR Neuroimaging.

At ultra-high magnetic fields, such as 7T, MR imaging can noninvasively visualize the brain in unprecedented detail and through enhanced contrast mechanisms. The increased SNR and enhanced contrast available at 7T enable higher resolution anatomic and vascular imaging. Greater spectral separation improves detection and characterization of metabolites in spectroscopic imaging. Enhanced blood oxygen level-dependent contrast affords higher resolution functional MR imaging. Ultra-high-field MR imaging also facilitates imaging of nonproton nuclei such as sodium and phosphorus. These improved imaging methods may be applied to detect subtle anatomic, functional, and metabolic abnormalities associated with a wide range of neurologic disorders, including epilepsy, brain tumors, multiple sclerosis, Alzheimer disease, and psychiatric conditions. At 7T, however, physical and hardware limitations cause conventional MR imaging pulse sequences to generate artifacts, requiring specialized pulse sequences and new hardware solutions to maximize the high-field gain in signal and contrast. Practical considerations for ultra-high-field MR imaging include cost, siting, and patient experience.

Diffuse meningeal enhancement in patients with overdraining, long-standing ventricular shunts.

The authors report two elderly men with diffuse meningeal enhancement 13 and 21 years following insertion of ventriculojugular shunts. Lumber puncture documenting low CSF pressures suggests that diffuse meningeal enhancement in patients with long-standing ventricular shunts may be secondary to dural venous dilatation rather than meningeal fibrosis. The authors theorize that these elderly patients, neither of whom had postural headache, may be less subject to brain "sag" because of decreased brain weight.

Spontaneous intracranial hypotension with pachymeningeal enhancement on MRI.

Spontaneous intracranial hypotension (SIH) is a rarely reported syndrome of spontaneously occurring postural cephalalgia associated with low CSF pressure. We report a case of SIH in which MRI of the brain revealed diffuse symmetric pachymeningeal enhancement that resolved without specific therapy.

Sonography and neurodiagnosis (neurosonography).

Sonography is a necessary part of neuroradiology. Its relative importance will increase as the sonographic images improve and the funds provided for diagnostic imaging decrease. We urge the incorporation of neurosonographic training into our neuroradiology fellowship programs and more widespread use of sonography in neurodiagnosis.

Periventricular white-matter cysts in a murine model of gram-negative ventriculitis.

Hydrocephalic patients with shunt infections frequently develop multiple cerebrospinal-fluid-density cysts that cause midline shift and life-threatening intracranial hypertension and respond poorly, if at all, to shunt diversion of cerebrospinal fluid. These cysts have been considered to represent multiloculation of the ventricular system by ependymal adhesions and veils resulting from ventriculitis. Studies using an experimental model of E. coli meningitis/ventriculitis in the hy-3 mouse suggest these cysts: (1) develop by the coalescence of lakes of white-matter edema, (2) grow to large size entirely within the periventricular white matter, and (3) cause pseudoloculation of the ventricle by compression from without. The so-called intraventricular septa or "veils" are the ependyma displaced inward by subependymal cysts or sheets of residual pericystic white matter. This finding permits better interpretation of computed tomographic images depicting persistent enlargement of the so-called multiloculations despite functioning ventricular shunt catheters, the multiplicity of cysts, and the white-matter location of these cysts.

Diastematomyelia: hemicord and meningeal sheaths; single and double arachnoid and dural tubes.

Metrizamide computed tomographic myelography demonstrates well: partial- and full-thickness diastematomyelia; the presence, shape, and (a)symmetry of the two hemicords; focal persistence of two anterior spinal arteries, one supplying each hemicord; the single or double subarachnoid space(s), arachnoid tubes, and dural tubes which encompass the hemicords; the dural septum formed by the medial walls of the two dural tubes; the dural cleft situated between the two walls of the dural septum; the bone spur within the dural cleft; and the presence of any tethering dorsal fibrous bands or aberrant dorsal nerve roots.

Sonography of the internal capsule and basal ganglia in infants: 1. Coronal sections.

Coronal sonograms in infants obtained with 3.5 and 5.0 MHz sector and linear-array transducers now depict the anterior limb, genu, posterior limb, and sublenticular parts of internal capsule; the caudate nucleus; the putamen; the lateral and medial nuclei of globus pallidus; the lateral and medial medullary laminae of the lenticular nucleus; the nucleus accumbens septi; and some of the thalamic nuclei. Correlation of sonograms obtained in vivo with gross and myelin-stained sections of human brain illustrates the configurations of these structures and the interrelations among them. Physicians familiar with this anatomy may now use sonography to localize focal lesions more accurately than has been possible previously.

Concurrent hydromyelia and diastematomyelia.

Hydromyelia was discovered in six of 13 patients with diastematomyelia. In one patient, hydromyelia affected only the segments of spinal cord above the diastematomyelia. In five patients, hydromyelia extended downward from the single cord into one or both hemicords. Because hydromyelia and diastematomyelia occur simultaneously, because they may produce very similar clinical changes, and because simultaneous or sequential surgical correction of both conditions may be necessary to achieve the best clinical result, the possibility of hydromyelia should be evaluated specifically in each patient demonstrated to have diastematomyelia.

The parasagittal line: an anatomic landmark for axial imaging.

BACKGROUND AND PURPOSE: No validated imaging landmark exists for characterizing the medial-lateral position of abnormalities at the high convexity-parasagittal region. Our understanding of the courses and deflections of the upper cerebral sulci is limited. Our purpose, therefore, was to define a frontooccipital line with reproducible anatomic relations to the upper cerebral gyri and sulci and to validate that line for use as an anatomic landmark by specific analysis of the gyral-sulcal relationships along it. METHODS: In 100 subjects of all ages, the gyri and sulci visualized on serial axial CT sections of the upper brain were traced onto a single flat surface to delineate the anatomic relationships among the midline interhemispheric fissure, the paramedian superior frontal sulci (SFS) and intraoccipital sulci (IOS), the medial surface sulci, the high convexity sulci, and the inner table of the skull. These tracings provided a template for drawing a straight, best-fit parasagittal line from the SFS to the IOS and for assessing how reproducibly key anatomic structures align along the parasagittal line. To assure the applicability of the line to MR imaging, selected relationships were retested on serial axial MR sections in the same subjects. RESULTS: The parasagittal line could be drawn in each case and showed reproducible alignment with the SFS, hand-motor area, partes marginales, pars deflections, postcentral "parentheses," distal intraparietal sulci, and IOS. In supraventricular sections, the parasagittal line separated the sulci arising along the medial surface from those arising along the convexity. CONCLUSION: Because the anatomic relationships of the parasagittal line are reproducible, it may serve as a reference line or landmark. The tendency of this line to demarcate medial sulci from convexity sulci suggests immediate application to the definition of vascular territories and vascular watersheds, a topic under active investigation.

Sonographic evaluation of caudal spine anomalies in children.

Retrospective analysis of B-mode spinal sonography in 15 pediatric patients with spinal dysraphism and caudal anomalies documents a high degree of accuracy in identifying the presence, site, size, and configuration of meningoceles; and slightly less accuracy in identifying extension of neural tissue into the meningocele and presence of concurrent lipoma. B-mode sonography is capable of displaying spinal anatomy clearly enough to permit accurate retrospective interpretation of pathologic changes. When radiologists learn to interpret sonographic images well enough to achieve equal accuracy in prospective diagnosis, then B-mode spinal sonography will supplant computed tomography and myelography as the preferred screening procedure in the initial evaluation of children with selected anomalies of the caudal spine.

Atrial diverticula in severe hydrocephalus.

Massive ventricular dilatation causes stretching and dehiscence of the fornix with formation of unilateral or bilateral pial pulsion diverticula of the inferior medial wall of the atrium. Enlargement of the pial pouch creates a dramatic subarachnoid cyst that may herniate downward through the incisura into the lateral mesencephalic, precentral cerebellar, and superior vermian cisterns where it displaces the brain stem, vermis, and fourth ventricle. Lateral ventricular diverticula may be identified and distinguished from the dilated fourth ventricle and dilated suprapineal recess, with which they are so commonly confused, when all of the following signs are apparent on computed tomography (CT): (1) marked unilateral or bilateral atrial dilatation; (2) focal dehiscence of the medial atrial wall; (3) ipsilateral shortening of the tentorial band in axial section; (4) focal defect in the tentorial band in coronal section; (5) draping of the medial atrial wall over the free margin of tentorium, with continuity of cerebrospinal fluid density around the edge of tentorium in axial and/or coronal sections; (6) bowing of the crus (or crura) of fornix; (7) separation of fornix from splenium, with visualization of the hernia ostium; (8) asymmetrical position of the choroid plexi, which attach to and define the lateral borders of the fornices; (9) contralateral displacement of the internal cerebral veins; and (10) septa separating diverticulum from third ventricle

The CT and MR evaluation of lissencephaly.

Lissencephaly is a rare congenital malformation of the brain that has characteristic radiographic and clinical findings. Fifteen cases of lissencephaly were studied with CT and/or MR, and a classification was developed based on these cases and the description of this abnormality found in the literature. These findings can be divided into two groups, primary and secondary. The primary findings consist of (1) a cerebral surface that is agyric or agyric with pachygyric areas, (2) a cerebral contour that is oval or "hourglass" due to lack of or incomplete opercularization of the brain, and (3) an abnormal gray-white-matter distribution in the cerebral hemispheres. The primary findings are necessary to make the diagnosis, which can be made with either CT or MR; however, MR provided better delineation than CT of the cerebral surface and contour as well as better gray-white-matter differentiation in the lissencephalic brains. We believe MR is the technique of choice for evaluating patients with lissencephaly because it is safer and more versatile than CT and provides better delineation of the brains of children.

MR imaging of neuronal migrational disorders.

Neuronal migrational disorders of the brain represent abnormalities in the formation of the neocortex caused by faulty migration of the subependymal neuroblasts. These migrational anomalies include lissencephaly (agyria/pachygyria), pachygyria, schizencephaly, heterotopias, hemimegalencephaly, and polymicrogyria. We used MR imaging (performed on a 0.5-T or 1.5-T scanner) to evaluate 21 patients who had neuronal migratory anomalies. Four patients had lissencephaly, seven had pachygyria, including one patient with hemimegalencephaly, seven had schizencephaly, and three had heterotopias. All MR scans included T1-weighted spin-echo sequences, and seven also had inversion-recovery sequences. The cortical surface, cortex, and gray-white matter interface were well evaluated with both sequences; however, the inversion-recovery images were superior. All but two patients were imaged in both the axial and coronal planes: both projections demonstrated well the migrational abnormalities. MR is an excellent method for diagnosing the migrational anomalies of lissencephaly, pachygyria, schizencephaly, heterotopias, and hemimegalencephaly; it appears to be the imaging method of choice for evaluating these disorders.

Creutzfeldt-Jakob disease: focal symmetrical cortical involvement demonstrated by MR imaging.

The authors present two biopsy-proved cases of Creutzfeldt-Jakob disease. MR appears to be more sensitive than CT in detecting pathologic changes; signal abnormalities, when found, are predominantly within gray matter and may involve only peripheral cortex.

Cervical MR imaging in postural headache: MR signs and pathophysiological implications.

BACKGROUND AND PURPOSE: Postural headache most often occurs after lumbar puncture as post-lumbar puncture headache (PLPH) or, rarely, spontaneously as spontaneous intracranial hypotension headache (SIHH). In this prospective study, we used spinal MR imaging to determine the findings that would assist in the diagnosis of PLPH and SIHH and that would further our pathophysiological understanding of postural headache. METHODS: The study group consisted of 15 healthy volunteers and 20 patients with postural headache: nine with SIHH and 11 with PLPH. The craniocervical junction and the cervical spine were studied using T2-weighted fast spin-echo and T1-weighted spin-echo sequences in the axial and sagittal planes. Follow-up studies were performed in 13 patients. RESULTS: Dilatation of the anterior internal vertebral venous plexus was the most constant finding, present in 17 (85%) of 20 patients with postural headache. Spinal hygromas, whose location as subdural or epidural could not be exactly determined, were present in 14 patients (70%). A focal fluid collection was detected in the retrospinal region at the C1-C2 level in six patients with SIHH and in four patients with PLPH (50%). Tonsillar descent was detected in only one patient, and subtentorial hygroma in five patients. No abnormalities were found in the volunteers. CONCLUSION: The MR signs of dilatation of the venous plexus, presence of spinal hygromas, and presence of retrospinal fluid collections can help to establish the diagnosis of intracranial hypotension. They are probably the result of decreased CSF volume, with the retrospinal fluid collections being a transudate from the venous plexus rather than frank extravasation. Resolution of these signs parallels resolution of the headache.