1. Fox MD. Mapping Symptoms to Brain Networks with the Human Connectome. N Engl J Med. 2018;379(23):2237-2245. doi:10.1056/NEJMra1706158.
Single-lesion analysis has been the foundation of clinical neurology and the basis for localization of most neurologic symptoms and behaviors. The traditional neurologic approach to localization of brain function has been by the identification of focal areas of damage, (for example- stroke) that correspond to a symptom or sign, such as paralysis.
It has become apparent that lesion-based localization is sometimes flawed because similar symptoms can result from lesions in different brain locations. For example, most lesions that disrupt language are located outside the left frontal cortex, most lesions that disrupt memory are located outside the hippocampus, and lesions that disrupt social behavior are frequently outside the frontal cortex. Even when the locations of lesions overlap between patients with the same symptom, the site of overlap may not conform to conventional ideas about the function of that part of the brain. For example, brain-stem lesions that cause visual hallucinations overlap in the midbrain and medial thalamus, but these locations have no clear role in vision or visual imagery. The relationship between symptoms and lesion location is therefore not straightforward.
Lesion-based localization is also limited by the fact that many complex symptoms occur in patients without overt brain lesions. Common neurobehavioral and psychiatric conditions, such as delirium, amnesia, autism, and schizophrenia, occur in patients with no obvious brain lesions.
If a complex behavior requires integrated function of multiple connected brain regions, lesions in any of these regions can disrupt behavior and lead to similar symptoms. For example, complex problem solving requires coordinated function of frontal and parietal regions, and lesions in either location degrade performance. Similarly, damage to the connection between regions can cause complex “disconnection” syndromes, while the cortical regions required …
Moonis G, Juliano AF, Mukherji S. Neuroimaging Clinics of North America: Update on Temporal Bone Imaging with Emphasis on Clinical and Surgical Perspectives; Elselvier; 2019; 202 pp; $397.00.
The February 2019 edition of the Neuroimaging Clinics discusses one of the most detailed areas of neuroradiology — temporal bone imaging. Edited by Drs. Moonis and Juliano, Update on Temporal Bone Imaging with an Emphasis on Clinical and Surgical Perspectives consists of the following 13 chapters:
- Meniere Disease
- Third Window
- Arterial Abnormalities
- Pediatric Hearing Loss
- Syndromic Temporal Bone Abnormalities
- Temporal Bone Trauma
- Management of Vestibelar Schwannomas
- Otologic Surgical Procedures
- Advanced MR Imaging
Thirty authors have contributed to this 200 page issue. Throughout the text there is an attempt to correlate — as well as possible — important clinical and surgical aspects of the topic under consideration. For example: audiograms of a number of abnormalities, tables for clinical classification of hearing loss, diagrams of aberrant arterial connections, sound conduction diagrams in normal and abnormal situations. The imaging quality is excellent throughout the book and the chapters are formatted in a similar manner.
This edition starts with a chapter on inflammation and it is particularly well done with an abundance of illustrations, tables, and well-outlined and described entities. Because of the myriad inflammatory diseases that affect the temporal bone, close attention to this material is appropriate, considering neuroradiologists’ daily evaluation of this area.
Updates on topics less frequently encountered include Meniere Disease and Third Window Lesions; however, the other topics are also important and well designed. Again, what is nice about this volume in general are the clinical correlations. In the trauma chapter, for example, many facts are emphasized and illustrated (like otic capsule involvement or sparing), the mechanism of force to cause these, and the otologic consequences. Side by …
The overwhelming benefit of endovascular therapy in patients with large-vessel occlusions suggests that more patients will be screened than treated. Some of those patients will be evaluated first at primary stroke centers; this type of evaluation calls for standardizing the imaging approach to minimize delays in assessing, transferring, and treating these patients. Here, we propose that CT angiography (performed at the same time as head CT) should be the minimum imaging approach for all patients with stroke with suspected large-vessel occlusion presenting to primary stroke centers. We discuss some of the implications of this approach and how to facilitate them.
Read this article: http://bit.ly/2GYJ36i…
1. Gallina P, Lastrucci G, Caini S, Lorenzo N Di, Porfirio B, Scollato A. Accuracy and safety of 1-day external lumbar drainage of CSF for shunt selection in patients with idiopathic normal pressure hydrocephalus. J Neurosurg. 2018:1-7. doi:10.3171/2018.6.JNS18400.
Cerebrospinal fluid shunting is the treatment of choice for idiopathic normal pressure hydrocephalus (iNPH) with a 75%–82% rate of successful outcome and 11% risk of serious adverse events. Not all patients diagnosed with iNPH are likely to benefit from shunt, and preoperative “supplemental prognostic tests” with intracranial pressure recording or CSF infusion/subtraction are recommended. External lumbar drainage (ELD) of CSF has gained wide acceptance among neurosurgeons as the best predictor of successful shunt surgery. The hypothesis underlying ELD is that prolonged drainage of a relatively large amount of CSF, more than with the spinal tap test, mimics a shunt effect.
Three to five days of external lumbar drainage of CSF is a test for ventriculoperitoneal shunt (VPS) selection in idiopathic normal pressure hydrocephalus. The accuracy and complication rates of a shorter (1-day) ELD procedure were analyzed.
Of 93 patients who underwent 1-day ELD, 3 did not complete the procedure. Of the remaining 90 patients, 2 experienced transient nerve root irritation. Twenty-four patients had negative test outcomes and 66 had positive test outcomes. Nine negative-outcome patients had intraprocedural headache, which showed 37.5% sensitivity and 100% specificity as predictors of negative 1-day ELD outcome. Sixty-eight patients (6 with negative and 62 with positive outcomes) underwent VPS insertion, which was successful in 0 and 58 patients, respectively, at 1-month follow-up.
They conclude that one-day ELD is a reliable tool in iNPH management, with low complication risk and short trial duration. The test is very consistent in predicting who will have a positive outcome with VPS placement, given the high chance of successful outcome at …