CSF-venous fistulas (CVFs) are an important cause of spontaneous intracranial hypotension and challenging to diagnose. Lateral decubitus positioning during myelography and a technique called \"resisted inspiration\" has shown to improve CVF detection. However, the impact of intrathecal pressurization to improve visualization of CVF has mostly been speculated on. In this brief report, we demonstrate how a CVF became progressively more visible only after stepwise intrathecal pressurization: An indication of the importance of pressurization for CVF detection.

Lipiodol, an oil-based contrast medium first introduced in 1944, was commonly used for various radiological exams until the 1980s, when it was replaced by water-soluble contrast media due to complications such as arachnoiditis and chronic irritations. Due to its slow resorption rate, asymptomatic lipiodol deposits can occasionally be found incidentally. This case report describes a 93-year-old man who presented to the emergency department after a fall. A non-contrast head CT scan, performed to rule out subarachnoid hemorrhage, revealed numerous hyperdense droplets in the subarachnoid spaces of the brain, primarily around the temporal lobes. Further investigation uncovered a previous pelvic X-ray showing similar hyperdense droplets around the cauda equina. The patient\'s history indicated a lipiodol myelography performed 51 years earlier. Lipiodol deposits are generally found in the lumbar region, making an intra-cranial location particularly rare. When present, these deposits are visible as radiopaque droplets on X-rays, hyperdense droplets on CT scans, and hyper-T1 on MRI, though the T2 signal is variable. Though lipiodol deposits are generally left untreated, symptomatic spinal deposits may be surgically removed. This rare case underscores the importance of thorough patient history in diagnosing subarachnoid lipiodol deposits, a condition relevant only in older patients who underwent myelography before the 1980s.

BACKGROUND: Chronic compressive myelopathy (CCM) is a major cause of spinal cord disorders in the elderly, in which the spinal cord is compressed by bony or soft tissue structures. Although computed tomography myelography (CTM) has been clinically used for the diagnosis of CCM, a method of CTM in rodents remains to be developed.
METHODS: A 50 μl Hamilton syringe attached to a disposable needle was percutaneously inserted into the subarachnoid space (cisterna magna) between the occipital bone and C1 lamina in an anesthetized adult mouse, followed by the injection of contrast medium and CT imaging.
RESULTS: CTM clearly visualized the shape of the spinal cord of intact mice and tiptoe-walking Yoshimura (Twy) mice without any health issues.
CONCLUSIONS: Unlike histology, the current method functions in live mice, directly depicts the compressed spinal cord, and provides clinically related image information. Furthermore, the intrathecal administration of contrast medium through the percutaneous route makes CTM less invasive and takes less time than a conventional intrathecal injection method.
CONCLUSIONS: The CTM method used in the present study enables clear visualization of the shape of the dural sac and spinal cord and is useful when conducting experiments on CCM and other spinal diseases in rodents.

BACKGROUND: Identifying spontaneous CSF leaks can be difficult on CT myelography (CTM) in patients with suspected spontaneous intracranial hypotension (SIH). The current study compared renal collecting system (RCS) density during CTM in patients with suspected SIH relative to non-SIH controls and evaluated the overall utility as an indirect sign of spontaneous CSF leak in patients with SIH.
METHODS: All CTM performed over an 8-year period (n = 392) were retrospectively reviewed and included cases (n = 295) were divided into groups consisting of SIH patients with (n = 35) or without (n = 77) confirmed CSF leak on CTM and non-SIH controls (n = 183). Average and relative average (relative to systemic contrast density) RCS densities were compared with multivariate analysis adjusting for patient characteristics and CTM technical differences.
RESULTS: Average RCS densities were greater for confirmed versus non-confirmed SIH groups and greater for both SIH groups relative to non-SIH controls. Correlations between RCS density and time from injection to CTM were higher within SIH patient groups compared to controls. Measured RCS density had a higher negative predictive value for excluding CSF leak both within the SIH patient groups as well as the overall cohort (84% and 96%, respectively), with optimized thresholds yielding 80% sensitivity and 70% specificity for the presence of leak in the overall cohort.
CONCLUSIONS: Accounting for RCS density may provide reliable additional indirect diagnostic value about the suspicion of a CSF leak in patients undergoing CTM for evaluation of SIH symptoms.

OBJECTIVE: The choroid plexus contains specialized ependymal cells responsible for CSF production. Recent studies have demonstrated volumetric and perfusion changes in the choroid plexus with age and neurodegenerative disorders, however, volumetric changes in the choroid plexus in low pressure states is not known. The purpose of this study is to evaluate volumetric differences in choroid plexus size in patients with spontaneous intracranial hypotension (SIH) resultant from spinal CSF leaks compared with healthy controls.
METHODS: This was a retrospective, institutional review board-approved study. Patients with MRI evidence of SIH and a spinal CSF leak diagnosed on myelography and subsequently confirmed at surgery were included in this study. All patients included in this study including age-matched healthy controls had a brain MRI performed on a either a 1.5 or 3T scanner with acquisition of 3D T1 postcontrast (eg, BRAVO, MPRAGE, etc). In all patients, the trigonum ventriculi volume, in the atria of the lateral ventricles, was contoured by using Visage-7 segmentation tools on the volumetric postcontrast T1 sequence. A basic 2-tailed t test was used to compare choroid plexus volumes between the 2 groups.
RESULTS: Thirty-four patients were included with 17 patients with SIH with spinal CSF leak and 17 healthy control patients who were age- and sex-matched. The mean age of patients was 45 years, standard deviation 14 years. The mean volume of the choroid plexus for patients with SIH with spinal CSF leak was 1.2 cm3 (standard deviation = 0.26) compared with 0.63 cm3 (standard deviation = 0.31) in the control group (P < .0001).
CONCLUSIONS: Results of this study demonstrate a higher choroid plexus volume in patients with SIH with spinal CSF leak compared with age- and sex-matched healthy controls. This likely reflects compensatory mechanisms to counteract intracranial hypotension by increasing CSF production as well as increased vascularity of the choroid plexus through expansion of the intracranial blood pool.

The confirmation of cerebrospinal fluid (CSF) leaks in the setting of spontaneous intracranial hypotension (SIH) by imaging involves a growing toolset of multimodal advanced spinal and skull base imaging techniques, for which exists a unique set of challenges for each CSF leak type. Furthermore, the repertoire of minimally invasive CSF leak treatment beyond nontargeted epidural blood patch administration has grown widely, with varied practices across institutions. This review describes current diagnostic imaging and treatment modalities as they apply to the challenges of CSF leak localization and management.

OBJECTIVE: Spinal CSF leaks cause spontaneous intracranial hypotension. Several types of leaks have been identified, and one of these types is the lateral dural tear. Performing myelography with the patient in the decubitus position allows precise characterization of these leaks. The purpose of the current study was to describe the different variants of spontaneous lateral CSF leaks.
METHODS: This retrospective cohort study included a consecutive group of patients with spontaneous intracranial hypotension and lateral CSF leaks who underwent digital subtraction myelography in the decubitus position and underwent surgery to repair the CSF leak between July 2018 and June 2023.
RESULTS: The mean age of the 53 patients (37 women and 16 men) was 35.5 years. Three different variants of lateral CSF leak could be identified. Forty-nine patients (92.5%) had a lateral dural tear associated with the nerve root sleeve. The dural tear was at the axilla of the nerve root sleeve in 36 patients (67.9%) and at the shoulder in 13 patients (24.5%). Four patients (7.5%) had a lateral dural tear at the level of the pedicle that was not associated with the nerve root sleeve. Findings on digital subtraction myelography were concordant with intraoperative findings in all patients. An extradural CSF collection was seen in all patients with a lateral dural tear associated with the nerve root sleeve but in only 2 of the 4 patients with the pedicular variant of a lateral dural tear.
CONCLUSIONS: We identified 3 variants of spontaneous lateral dural tears. Most lateral dural tears are associated with extradural CSF collections and arise from either the axilla (67.9%) or the shoulder (24.5%) of the nerve root sleeve. Lateral dural tears at the level of the pedicle (7.5%) not associated with the nerve root sleeve are uncommon and may require specialized imaging for their detection.

Cerebrospinal fluid-venous fistulas (CSFVFs) were first described in 2014 and have since become an increasingly diagnosed cause of spontaneous intracranial hypotension due to increased clinical recognition and advancements in diagnostic modalities. In this review, the authors discuss CSFVF epidemiology, the variety of clinical presentations, the authors\' preferred diagnostic approach, recent advancements in diagnostic methods, treatment options, current challenges, and directions of future research.

Spontaneous intracranial hypotension (SIH) is an important cause of daily headaches that occur in young and middle-aged, active persons and is often misdiagnosed, leading to prolonged inactivity and rather high healthcare expenditures. Its diagnosis requires a high degree of clinical suspicion and careful interpretation of imaging studies. We present a case of SIH, which was successfully treated but which posed serious diagnostic challenges, ranging from cerebro-vascular disease and meningitis to granulomatous diseases, and for whom every therapeutic attempt just worsened the patient\'s condition until we finally reached the correct diagnosis. To raise awareness of this condition, we also present an updated overview of the clinical picture, evaluation, and treatment options for SIH.

BACKGROUND: The diagnosis of lumbar spinal stenosis (LSS) can be challenging because radicular pain is not often present in the culprit-level localization. Accurate segmentation and quantitative analysis of the lumbar dura on radiographic images are key to the accurate differential diagnosis of LSS. The aim of this study is to develop an automatic dura-contouring tool for radiographic quantification on computed tomography myelogram (CTM) for patients with LSS.
METHODS: A total of 518 CTM cases with or without lumbar stenosis were included in this study. A deep learning (DL) segmentation algorithm 3-dimensional (3D) U-Net was deployed. A total of 210 labeled cases were used to develop the dura-contouring tool, with the ratio of the training, independent testing, and external validation datasets being 150:30:30. The Dice score (DCS) was the primary measure to evaluate the segmentation performance of the 3D U-Net, which was subsequently developed as the dura-contouring tool to segment another unlabeled 308 CTM cases with LSS. Automatic masks of 446 slices on the stenotic levels were then meticulously reviewed and revised by human experts, and the cross-sectional area (CSA) of the dura was compared.
RESULTS: The mean DCS of the 3D U-Net were 0.905 ± 0.080, 0.933 ± 0.018, and 0.928 ± 0.034 in the five-fold cross-validation, the independent testing, and the external validation datasets, respectively. The segmentation performance of the dura-contouring tool was also comparable to that of the second observer (the human expert). With the dura-contouring tool, only 59.0% (263/446) of the automatic masks of the stenotic slices needed to be revised. In the revised cases, there were no significant differences in the dura CSA between automatic masks and corresponding revised masks (p = 0.652). Additionally, a strong correlation of dura CSA was found between the automatic masks and corresponding revised masks (r = 0.805).
CONCLUSIONS: A dura-contouring tool was developed that could automatically segment the dural sac on CTM, and it demonstrated high accuracy and generalization ability. Additionally, the dura-contouring tool has the potential to be applied in patients with LSS because it facilitates the quantification of the dural CSA on stenotic slices.