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Spontaneous intracranial hypotension (SIH) is caused by spinal cerebrospinal fluid (CSF) leaks, which result in continued loss of CSF volume and multiple debilitating clinical manifestations. The estimated annual incidence of SIH is 5/100,000. Diagnostic methods have evolved in recent years due to improved understanding of pathophysiology and implementation of advanced myelographic techniques. Here, we synthesize recent updates and contextualize them in an algorithm for diagnosis and treatment of SIH, highlighting basic principles and points of practice variability or continued debate. This discussion includes finer points of SIH diagnosis, CSF leak classification systems, less common types and variants of CSF leaks, brain MRI Bern scoring, potential SIH complications, key technical considerations, and positioning strategies for different types of dynamic myelography. The roles of conservative measures, non-targeted or targeted blood patches, surgery, and recently developed endovascular techniques are presented.

Laser interstitial thermal therapy (LITT) is an emerging treatment modality for both primary brain tumors and metastases. We report initial outcomes after LITT for metastatic brain tumors across 3 sites at our institution and discuss potential strategies for optimal patient selection and outcomes.International Classification of Diseases, Ninth Revision and Tenth Revision codes were used to identify patients with malignant brain tumors treated via LITT across all 3 Mayo Clinic sites with at least 6 months follow-up. Local control was based on radiologic and clinical evidence. Overall survival was measured from time of receiving LITT until death or end of the study period.Twenty-three patients were treated for progression of a single (n = 21) or multiple (n = 2) previously radiated metastatic lesions and/or radiation necrosis. Median age was 56 years (interquartile range, 47-66.5 years). LITT achieved local control of the lesion in most patients with metastatic tumors or radiation necrosis (n = 18; 81.8%) for the duration of follow-up. One patient did not have local control data available. Thirteen (56.5%) patients remained alive at the end of the study period. No other patients died of their treated disease during the study period; 5 of 10 deaths were attributable to central nervous system progression outside the treated lesion. Although median survival for this cohort has not yet been reached, the current median survival is 16 months (interquartile range, 12-48.5 months) after LITT for metastatic/radiation necrosis lesions.LITT was associated with sustained local control in 81.8% of patients treated for radiographic progression of metastatic central nervous system disease.

El Fin del Mundo is an archaeological site in Sonora, northwest Mexico, that contains a buried Clovis megafauna kill in a lowland area and concentrations of Clovis and later lithic materials scattered on the deflated surface of the surrounding uplands. The Clovis lithic assemblage from the site, identified by its technological and typological features, has been classified into three modes: bifaces, unifaces, and blades. The kill locality only contains Clovis points, whereas the assemblage from the uplands includes multiple bifaces reflecting diverse stages of the manufacture process from blank production to finished, highly reduced, and discarded broken Clovis points, numerous end scrapers, and blades and blade manufacture byproducts. This assemblage is indicative of a campsite where stone tool production and possibly other domestic tasks took place. In addition, a rhyolite outcrop near both the campsite and the kill was intensively exploited, as reflected in the high proportion of this raw material in the Clovis assemblage. Unequivocal association of the kill locality and the campsite is not confirmed; however, the configuration of the site indicates that the campsite was established in uplands near locations with water, game, and lithic resources.

Since its approval in treating a number of movement disorders, magnetic resonance imaging–guided focused ultrasound (MRgFUS) has been adopted rapidly as one of the standard treatment modalities internationally. However, the efficiency of the energy delivered by the ultrasonic waves is largely determined by the highly variable bone morphology and density characteristics of the skull. One of the widely accepted indices used to facilitate patient selection is the skull density ratio (SDR). Earlier literature suggested that an SDR of less than 0.4 would be unfavorable for MRgFUS treatment. Some prior studies have excluded patients with hyperostosis. However, there is little published data regarding the impact of other skull features such as hyperostosis on treatment success. We present the case of a 66-year-old man with medically refractory essential tremor who had an SDR of 0.38 and extensive hyperostosis frontalis interna and underwent attempted MRgFUS thalamotomy treatment. However, intraoperatively the treatment was unsuccessful in generating sufficiently elevated temperature to create a lesion of the usual desired volume, and as expected, there was minimal clinical improvement. For comparison, we also summarize a case series of 4 other patients with an SDR of less than 0.4 who had successful outcomes. We believe that SDR should not be used as the only means of selecting patients for MRgFUS. Instead, important factors such as hyperostosis should be taken into consideration for patient selection and pretreatment counseling.

Intracranial vessel wall MR imaging (VWI) is increasingly being used as a valuable adjunct to conventional angiographic imaging techniques. This article will provide an updated review on intracranial VWI protocols and image interpretation. We review VWI technical considerations, describe common VWI imaging features of different intracranial vasculopathies and show illustrative cases. We review the role of VWI for differentiating among steno-occlusive vasculopathies, such as intracranial atherosclerotic plaque, dissections and Moyamoya disease. We also highlight how VWI may be used for the diagnostic work-up and surveillance of patients with vasculitis of the central nervous system and cerebral aneurysms.

The Northern Rocky Mountain Front (hereafter Northern Front) is a prominent geographic feature in archaeological models of human dispersal in the terminal Pleistocene and Early Holocene of North America. Testing those models has been arduous because of local geomorphological factors that tend to obliterate or otherwise limit access to archaeological finds of relevant age. In this paper, we present well-stratified archaeological and environmental records dating back to 14,000–13,000 cal yr BP from the site of Billy Big Spring (Blackfeet Indian Reservation, Montana), located on a glacial kettle, a type of landform that has been largely ignored by regional archaeological research to date. Findings from Billy Big Spring show the continuous use of the Northern Front foothills throughout the major climatic and environmental disturbances of the Early Holocene, and possibly the terminal Pleistocene as well. As such, Billy Big Spring contributes to refining several archaeological models of early settlement of the Northern Front, particularly those that posit differential use of foothills versus plains settings during the midst of the Holocene Thermal Maximum. The record at Billy Big Spring also suggests that kettles, regardless of physiographic setting, provide a yet unsuspected and unsampled potential for preserving high-quality and easily accessible early archaeological and paleoenvironmental records.

Intrathecal gadolinium magnetic resonance (MR) myelography can be used to localize various types of spinal cerebrospinal fluid (CSF) leaks; however, its diagnostic yield is not well known. We sought to determine the diagnostic yield of MR myelography in patients with spontaneous intracranial hypotension. A retrospective review was performed on all patients who had undergone intrathecal gadolinium MR myelography at our institution from 2002 to 2020 for suspected spinal CSF leak. The MR myelography images were reviewed for the presence or absence of a spinal CSF leak site. Images were also evaluated for the presence an extradural fluid collection. A total of 97 patients were included in the final cohort. The average age was 52.6 years; 67.0% were female, 4 patients underwent 2 examinations each, yielding a total of 101 MR myelograms. The source of a spinal CSF leak was localized in 14 patients. The diagnostic yield for CSF leak localization on intrathecal gadolinium MR myelography was 14/101 (13.9%) per GdM examination and 14/97 (14.4%) per patient. Among the subset of patients without extradural fluid collections, the yield was 15.7% per examination. All detected leaks were either CSF-venous fistulas or distal nerve root sleeve tears. Intrathecal gadolinium MR myelography is capable of localizing CSF-venous fistulas and distal nerve root sleeve tears; however, our data show that it has a limited diagnostic yield. We suggest that other modalities may be a better first step before attempting intrathecal gadolinium MR myelography.

Spinal metastases are most commonly osseous and may extend to the epidural space. Less commonly, spinal metastases can be subdural, leptomeningeal, or intramedullary. Among these, subdural metastases are the most rare, with few reported cases. While these lesions are now almost exclusively detected on MRI, they can rarely be apparent on other modalities. It is important to recognize subdural metastases on any modality, because they have a significant impact on patient prognosis and treatment. We report a case of renal cell carcinoma in a 68-year-old male initially presenting with subdural metastases detected on CT myelography, with subsequent confirmation by MRI. The case illustrates, to our knowledge, the first example of subdural metastatic disease seen on CT myelography.