Computed Tomography Myelogram Research Articles

Automatic segmentation of dura for quantitative analysis of lumbar stenosis: A deep learning study with 518 CT myelograms.

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. 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. 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). 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.

Validation of the Root Analysis Score for C5 Viability in Patients With Pan–Brachial Plexus Injury

Pan-brachial plexus injury patients present a reconstructive challenge. The root analysis score, developed from parsimonious multivariable modeling of 311 pan-brachial plexus injury patients, determines the probability of having a viable C5 nerve based on four categories: positive C5 Tinel test, intact C5 nerve on computed tomography myelogram, lack of hemidiaphragmatic elevation, and absence of midcervical paraspinal fibrillations. Root analysis scores were calculated for a separate cohort of patients with pan-brachial plexus injuries. Scores were validated by the presence or absence of a graftable C5 root, based on supraclavicular exploration and intraoperative electrophysiologic testing. Receiver operating characteristic curve, accuracy, and concordance statistic of the scores were calculated. Patients were divided into three root analysis score cohorts: less than 50 (low), 50-75 (average), and 75-100 points (high) based on dividing the score into quartiles and combining the lowest two. The probability, sensitivity, and specificity of each cohort having an available C5 nerve were based on the intraoperative assessment. Eighty patients (mean age, 33.1 years; 15 women and 65 men) were included. Thirty-one patients (39%) had a viable C5 nerve. The root analysis calculator had an overall accuracy of 82.5%, a receiver operating characteristic of 0.87, and a concordance statistic of 0.87, demonstrating high overall predictive value; 6.5% of patients with a score of less than 50 (94% sensitivity and 43% specificity), 16.1% of patients with a score of 50-75 (94% sensitivity and 67% specificity), and 77.4% of patients with a score of 75-100 (77% sensitivity and 90% specificity) had a graftable C5 nerve. The root analysis score demonstrated high accuracy and predictive power for a viable C5 nerve. In patients with a score of less than 50, the necessity of supraclavicular root exploration should balance patient factors, presentation timing, and concomitant injuries. Diagnosis II.

Which Tests Should Be Routinely Ordered Prior to Brachial Plexus Reconstruction? Results of a Delphi Panel

Background: There are notable differences in how adult patients with traumatic brachial plexus injuries (BPI) are evaluated and treated. Purpose: To better understand existing philosophies, we used the Delphi method to measure and foster consensus on routine use of electrodiagnostic testing, ultrasound, magnetic resonance imaging (MRI), and computed tomography (CT) myelograms prior to surgery. Panelists were 10 peripheral nerve surgeons board certified in their respective specialties at 5 academic medical centers in the United States. Methods: We presented 2 cases (1 complete/pan-BPI and 1 upper trunk BPI) to panelists and asked how often they would order the following preoperative diagnostic tests: electrodiagnostic studies; ultrasound of the brachial plexus; MRI of the brachial plexus; CT myelogram. Our Delphi process included an initial survey with videoconference discussion after the first round. A second survey/videoconference round was conducted to further probe the items that did not reach consensus during the first round. Results: Among the 10 surgeons, there was consensus that prior to brachial plexus surgery electrodiagnostic studies and MRI should be routinely ordered and ultrasound of the brachial plexus should not be routinely ordered. The group did not reach consensus on whether CT myelogram should or should not be routinely ordered. Conclusions: Based on our panel’s discussion, future work should focus on comparing the accuracy of CT myelogram and MRI for evaluation of cervical nerve root presence and viability.

Quantification of MRI Artifacts in Carbon Fiber Reinforced Polyetheretherketone Thoracolumbar Pedicle Screw Constructs prior to Spinal Stereotactic Radiosurgery

Carbon fiber reinforced polyetheretherketone (CFRP) is a nonmetallic material that is a subject of growing interest in the field of spinal instrumentation manufacturing. The radiolucency and low magnetic susceptibility of CFRP has potential to create less interference with diagnostic imaging compared with titanium implants. However, an objective comparison of the image artifact produced by titanium and CFRP implants has not been described. Spinal oncology, particularly after resection of spinal tumors and at the time of spinal stereotactic radiosurgery planning, relies heavily on imaging interpretation for evaluating resection, adjuvant treatment planning, and surveillance. We present a study comparing measurements of postoperative magnetic resonance imaging artifacts between titanium and CFRP pedicle screw constructs in the setting of separation surgery for metastatic disease. The diameter of the signal drop around the screws (pedicle screw artifact) and the diameter of the spinal canal free from artifacts (canal visualization) were measured in consecutive patients who had spinal instrumentation followed by spinal stereotactic radiosurgery in the June 2019 to May 2022 timeframe. The spinal cord presented a shift at the screw level in sagittal images which was also measured (Sagittal Distortion, SagD). Fifty patients, corresponding to 356 screws and 183 vertebral levels, were evaluated overall. CFRP produced less artifacts in all the 3 parameters compared with titanium: mean pedicle screw artifact (CFRP = 5.8 mm, Ti = 13.2 mm), canal visualization (CFRP = 19.2 mm, Ti = 15.5 mm), and SagD (CFRP = .5 mm, Ti = 1.9 mm), all P < .001. In practice, these findings translate into better-quality magnetic resonance imaging. The initial perceived advantages are easier evaluation of postoperative imaging, facilitating radiation treatment planning, recurrence detection, and avoidance in repeating a suboptimal computed tomography myelogram. Further clinical studies analyzing long-term outcomes of patients treated with CFRP implants are necessary.

Spontaneous Intracranial Hypotension: A Review of Neuroimaging and Current Concepts.

Spontaneous intracranial hypotension (SICH) is the emerging cause of orthostatic headache as it has been better recognized in recent years. SICH happens due to spinal cerebrospinal fluid (CSF) leak; however, the manifestations are predominantly cranial and hence imaging in SICH includes brain and spine. There are few characteristic brain imaging features to be concerned about to diagnose SICH in patients with vague symptoms or low clinical suspicion. Spine screening is recommended in these patients to assess spinal CSF leaks. While neuroradiologists play a significant role from the time of diagnosis to treatment of SICH, there is a need for all the general radiologists to be aware of the condition. Computed tomography myelogram and digital subtraction myelogram are performed for diagnostic and therapeutic management of SICH. There is a known risk for SICH recurrence in patients with sagittal longitudinal epidural collection and hence, targeted blood patch should be used instead of blind patch. Most importantly, slow mobilization is recommended following the patch to avoid recurrence.

The clue is in the kidneys: greater renal contrast medium accumulation on ipsilateral side down CT myelogram after lateral decubitus digital subtraction myelogram as a predictor of laterality of cerebrospinal fluid leak

To assess the potential correlation of the laterality of a cerebrospinal fluid (CSF)-venous fistula with the laterality of decubitus computed tomography (CT) myelogram (post decubitus digital subtraction myelogram) based on which side demonstrated more renal contrast medium excretion.Patients with CSF-venous fistulas diagnosed at lateral decubitus digital subtraction myelograms were reviewed retrospectively. Patients who did not have CT myelogram following one or both left and right lateral decubitus digital subtraction myelograms were excluded. Two neuroradiologists independently interpreted the CT myelogram for the presence or absence of renal contrast, and whether subjectively more renal contrast medium was visualised on the left or right lateral decubitus CT myelogram.Renal contrast medium was seen in lateral decubitus CT myelograms in 28 of 30 (93.3%) patients with CSF-venous fistulas. Having more renal contrast medium in right lateral decubitus CT myelogram was 73.9% sensitive and 71.4% specific for the diagnosis of a right-sided CSF-venous fistula, whereas having more renal contrast medium in the left lateral decubitus CT myelogram was 71.4% sensitive and 82.6% specific for a left-sided CSF-venous fistula (p=0.02).When the CSF-venous fistula lies on the dependent side of a decubitus CT myelogram performed after decubitus digital subtraction myelogram, relatively more renal contrast medium is visualised compared to when the fistula lies on the non-dependent side.

Subarachnoid Fat Globules Following Spinal Surgery: A Case Report (P3-4.003)

<h3>Objective:</h3> To present a rare case of intracranial subarachnoid fat globules in a patient with a recent history of lumbar laminectomy. <h3>Background:</h3> Fat globules in the subarachnoid space are a rare phenomenon which has previously been described in association with the rupture of dermoid/epidermoid tumors of the central nervous system, or secondary to subarachnoid fat embolism in the setting of traumatic spinal injury. Computed tomography (CT) characteristics of the fat tissue resemble pneumocephalus with the hypodense appearance which might create a diagnostic challenge requiring magnetic resonance imaging (MRI). Here, we present a rare case of a patient with subarachnoid fat globules without any preceding intracranial/intraspinal tumor or traumatic injury of the neuroaxis. <h3>Design/Methods:</h3> Retrospective case review <h3>Results:</h3> A 65-year-old male presented with five weeks of daily, bitemporal, throbbing headache. Headaches started two weeks after a lumbar laminectomy. He reported his headaches built up gradually in the afternoon with increasing intensity throughout the day. They improved when lying down and sleeping overnight. There were no other associated complaints. The patient was evaluated for potential intracranial hypotension as the etiology of his headaches. Initially his CT brain reported potential air pockets in the suprasellar cistern region. MRI of the brain later identified these as multiple lobules of fat in the subarachnoid space in the inferior margin of the cerebellum, 4th ventricle and suprasellar and quadrigeminal cisterns. MRI of the neuroaxis was otherwise negative for fat tissue in the subarachnoid space. MRI of the lumbar spine showed localized soft tissue fluid collection. CT myelogram confirmed cerebrospinal fluid (CSF) leak at L4–5 in the vicinity of the thecal sac. <h3>Conclusions:</h3> The differential diagnosis of subarachnoid fat globules should include iatrogenic causes such as spinal surgery. <b>Disclosure:</b> Dr. Zhao has nothing to disclose. Dr. Beck has nothing to disclose. Dr. Erol has nothing to disclose. Dr. Gul has nothing to disclose. The institution of Dr. Beach has received research support from Neurona.

Spontaneous Intracranial Hypotension Due to CSF Leak at Multiple Spinal Levels—A Case Report and Literature Review

Abstract Introduction Spontaneous intracranial hypotension (SIH) is a misdiagnosed condition characterized by low cerebrospinal fluid (CSF) volume and an orthostatic headache that worsens with upright posture due to CSF leak at spinal dural defects. SIH due to CSF leak at multiple spinal levels is a rare condition, and only a few cases have been reported in the literature. Here, we report a case of SIH with a CSF leak at multiple spinal levels. The treatment options and efficacy of epidural blood patch (EBP) injection were discussed in this article. Case Report A 36-year-old man presented with complaints of orthostatic headache for 2 months and a computed tomography myelogram demonstrated CSF leaks at multiple spinal levels through the dural defects at C5-C6, C6-C7, C7-T1, T1-T2 levels, and at L1, L2, L3, and L4 vertebral levels on the left side. He was managed with a targeted EBP injection and he improved symptomatically within 24 hours of the EBP injection. Summary SIH is an entity that results from CSF leakage, often through spinal dural defects due to mechanical tear by osteophyte complex, disc prolapse, connective tissue disorders, CSF-venous fistula, and leaking meningeal diverticula. SIH can result from single or multiple dural leaks, but spinal leaks at multiple levels are uncommon. To the best of our knowledge, a total number of 163 cases have been reported in the literature so far. With good success rates, targeted EBP injection with autologous blood is an effective treatment option for both single-level and multiple-level spinal leaks.

Spinal Cord Delineation Based on Computed Tomography Myelogram Versus T2 Magnetic Resonance Imaging in Spinal Stereotactic Body Radiation Therapy

Spinal cord delineation is critical to the delivery of stereotactic body radiation therapy (SBRT). Although underestimating the spinal cord can lead to irreversible myelopathy, overestimating the spinal cord may compromise the planning target volume coverage. We compare spinal cord contours based on computed tomography (CT) simulation with a myelogram to spinal cord contours based on fused axial T2 magnetic resonance imaging (MRI). Eight patients with 9 spinal metastases treated with spinal SBRT were contoured by 8 radiation oncologists, neurosurgeons, and physicists, with spinal cord definition based on (1) fused axial T2 MRI and (2) CT-myelogram simulation images, yielding 72 sets of spinal cord contours. The spinal cord volume was contoured at the target vertebral body volume based on both images. The mixed-effect model assessed comparisons of T2 MRI- to myelogram-defined spinal cord in centroid deviations (deviations in the center point of the cord) through the vertebral body target volume, spinal cord volumes, and maximum doses (0.035 cc point) to the spinal cord applying the patient's SBRT treatment plan, in addition to in-between and within-subject variabilities. The estimate for the fixed effect from the mixed model showed that the mean difference between 72 CT volumes and 72 MRI volumes was 0.06 cc and was not statistically significant (95% confidence interval, -0.034, 0.153; P=.1832). The mixed model showed that the mean dose at 0.035 cc for CT-defined spinal cord contours was 1.24 Gy lower than that of MRI-defined spinal cord contours and was statistically significant (95% confidence interval, -2.292, -0.180; P=.0271). Also, the mixed model indicated no statistical significance for deviations in any of the axes between MRI-defined spinal cord contours and CT-defined spinal cord contours. CT myelogram may not be required when MRI imaging is feasible, although uncertainty at the cord-to-treatment volume interface may result in overcontouring and hence higher estimated cord dose-maximums with axial T2 MRI-based cord definition.

Morphological changes in nerve rootlets in patients with cervical radiculopathy assessed using computed tomography myelogram.

Background: There are only a few reports that utilize computed tomography myelogram (CTM) to define cervical nerve rootlet compromise in patients with radiculopathy. Here, we assessed the characteristic morphological changes in nerve rootlets in 32 cases with cervical radiculopathy by analyzing CTMs warranting anterior foraminotomy.Methods: CTMs were analyzed to elucidate morphological changes in nerve rootlets in 31 patients/32 cases with cervical radiculopathy. Notably, three of the four neurosurgeons evaluating these CTM had to agree on the presence of “significant” changes consisting of contrast-enhanced defects near the entrance of the intervertebral foramen on axial sections.Results: Our findings included; posterior deviation of the ventral rootlet on the sagittal section (63%), ventral rootlet meandering or horizontalization (52%), and dorsal rootlet meandering (39%) on the coronal section. Furthermore, 16% of cervical nerve rootlets may exhibit an abnormal course proximal to the compression site (i.e., the definition of the “rootlet stagnation sign”).Conclusion: CTM better defines the anatomy, pathology, and radiology impacting the anterior or posterior cervical roots in patients presenting with cervical radiculopathy.

Single and Multifraction Spine Stereotactic Body Radiation Therapy and the Risk of Radiation Induced Myelopathy

PurposeThis study reports on the risk of radiation-induced myelitis (RM) of the spinal cord from a large single-institutional experience with 1 to 5 fraction stereotactic body radiation therapy (SBRT) to the spine. Methods and MaterialsA retrospective review of patients who received spine SBRT to a radiation naïve level at or above the conus medullaris between 2007 and 2019 was performed. Local failure determination was based on SPIne response assessment in Neuro-Oncology criteria. RM was defined as neurologic symptoms consistent with the segment of cord irradiated in the absence of neoplastic disease recurrence and graded by Common Toxicity Criteria for Adverse Events, version 4.0. Rates of adverse events were estimated and dose-volume statistics from delivered treatment plans were extracted for the planning target volumes and spinal cord. ResultsA total of 353 lesions in 277 patients were identified that met the specified criteria, for which 270, 70, and 13 lesions received 1-, 3-, and 5-fraction treatments, respectively, with a median follow-up of 46 months (95% confidence interval [CI], 41-52 months) for all surviving patients. The median overall survival was 33.0 months (95% CI, 29-43). The median D0.03cc to the spinal cord was 11.7 Gy (interquartile range [IQR], 10.5-12.4), 16.7 Gy (IQR, 12.8-20.6), and 26.0 Gy (IQR, 24.1-28.1), for 1-, 3-, 5-fractions. Using an a/b = 2Gy for the spinal cord, the median single-fraction equivalent-dose (SFED2) was 11.7 Gy (IQR, 10.2-12.5 Gy) and the normalized biological equivalent dose (nBED2/2) was 19.9 Gy (IQR, 15.4-22.8 Gy). One patient experienced grade 2 RM after a single-fraction treatment. The cumulative probability of RM was 0.3% (95% CI, 0%-2%). ConclusionsSpine SBRT is safe while limiting the spinal cord (as defined on treatment planning magnetic resonance imaging or computed tomography myelogram) D0.03cc to less than 14 Gy, 21.9 Gy, and 30 Gy, for 1, 3, and 5-fractions, consistent with standard guidelines.

T2-Sampling Perfection With Application-Optimized Contrasts by Using Flip Angle Evolution (SPACE) Protocol MRI: A Safe, Minimally Invasive Screening Tool for Spinal CSF Leak Causing Spontaneous Intracranial Hypotension

Spontaneous intracranial hypotension (SIH) due to a spinal cerebrospinal fluid (CSF) leak is secondary cause of headache with potentially devastating consequences. Its diagnosis is complicated owing to the lack of a reasonable, minimally invasive screening test. This results in many patients remaining undiagnosed for years after the headache onset. Current testing approaches are either overly invasive, namely the CSF infusion protocol or both invasive and insensitive viz. lumbar puncture (LP) with an opening pressure (OP) or computed tomography myelogram (CTM). These diagnostic methods are frequently employed in a clinical setting since they require access to the thecal space; they unfortunately have a dearth of sensitivity. CTM will not document a leak if it is intermittent or very slow and in the setting of a spinal CSF leak, the OP on LP may be high, low, or normal. A potential remedy for this state is the T2-sampling perfection with application-optimized contrasts by using flip angle evolution (SPACE) protocol spinal magnetic resonance imaging (MRI). We present two cases that demonstrate its potential value as a screening tool. It is well known for its high sensitivity for identifying spinal pathology and is minimally invasive, making it a good choice for a screening modality when diagnosing possible SIH cases.

Delineating the Subarachnoid Space in the Adult Lumbosacral Spine Using Computed Tomographic Myelography: An Aid for Clinical Target Volume Delineation in Craniospinal Irradiation

PurposeOur aim was to characterize the patterns of cerebrospinal fluid (CSF) extension in the lumbosacral spine using computed tomography (CT) myelograms to provide an evidence base for clinical target volume (CTV) definition in adults receiving craniospinal irradiation. Methods and MaterialsThis was a retrospective analysis of diagnostic CT lumbar myelograms performed in 30 patients between the ages of 22 and 50. Lateral extension of CSF beyond the thecal sac was measured along each lumbar and sacral nerve root to the nearest millimeter, as was the distance of inferior extension of CSF beyond the caudal end of the thecal sac. Each patient's lateral and inferior CSF extensions were mapped onto a standardized CT data set to create a model target volume in the lumbosacral spine that would contain the aggregate observed CSF distributions from the analyzed CT myelograms. The median extension distances, interquartile ranges, and 90th percentile for distance at each level were calculated. ResultsThe median lateral extension of CSF along nerve roots beyond the thecal sac—as measured perpendicular to the longitudinal axis—increased from 0 mm (interquartile range [IQR], 0-4 mm) at L1 to 8 mm (IQR, 6-12 mm) at S1 and 0 mm (IQR, 0-0 mm) at S4. The 90th percentile ranged from 5 to 14 mm laterally, with a pattern partially extending into the S1 and S2 sacral foramen. Median CSF extension inferior to the caudal sac was 5 mm (IQR, 2-8 mm), with 90% of patients within 12 mm. An atlas was generated to guide CTV delineation for highly conformal radiation techniques. ConclusionThese results provide information on patterns of CSF extension in the lumbosacral spine of adults and can serve as a model for CTV guidelines that balance comprehensive coverage of the CSF compartment while minimizing the dose to nontarget tissues.

Intracranial hypotension due to ventral thoracic dural tear secondary to osteophyte complex: resolution after transdural thoracic microdiscectomy with dural repair. Illustrative case.

BACKGROUNDIntracranial hypotension (IH) manifests with orthostatic headaches secondary to cerebrospinal fluid (CSF) hypovolemia. Common iatrogenic etiologies include lumbar punctures and spinal surgery. Although much rarer, structural defects such as osteophytes and herniated calcified discs can violate dural integrity, resulting in CSF leak.OBSERVATIONSThe authors reported the case of a 32-year-old woman who presented with progressively worsening orthostatic headaches. During an extensive examination, magnetic resonance imaging of her thoracic spine revealed a cervicothoracic ventral epidural collection of CSF, prompting a dynamic computed tomography myelogram, which not only helped to confirm severe cerebral hypotension but also suggested underlying pathology of a dorsally projecting disc osteophyte complex at T2–3. Conservative and medical management failed to alleviate symptoms, and a permanent surgical cure was eventually sought. The patient underwent a transdural thoracic discectomy with dural repair, which resulted in resolution of her symptoms.LESSONSClear guidelines regarding the management strategy of IH secondary to disc osteophyte complexes are yet to be established. A thorough literature review noted only 24 reported cases between 1998 and 2019, in which 13 patients received surgery. There is a 46% symptom resolution rate with conservative management, lower than that for iatrogenic etiologies. For patients in whom conservative management failed, surgical intervention proved effective in resolving symptoms, with a success rate of 92.3%.

Modified Clavipectoral Fascial Plane Block to The Rescue: Polytrauma Patient with Brachial Plexus Injury Undergoing Awake Clavicle Surgery

Modified Clavipectoral Fascial Plane Block to The Rescue: Polytrauma Patient with Brachial Plexus Injury Undergoing Awake Clavicle Surgery

Small L4 ventral root schwannoma with acute onset of radicular pain: A case report

Background: Patients with cauda equina schwannomas usually present with slowly progressive radiculopathy. Herein, we describe a 34-year-old male who presented with acute radiculopathy attributed to a small L4 ventral root schwannoma.Case Description: A 34-year-old male suddenly developed left leg pain. Magnetic resonance imaging (with/without contrast) revealed a small intradural mass lesion involving the L4 nerve root that was enhanced with contrast (size: 9 × 12 × 12 mm). The computed tomography myelogram revealed that the tumor had originated from the L4 ventral root and compressed the dorsal root in the lateral recess. Following a decompressive laminectomy for tumor removal, the patient’s radicular pain improved. The histological diagnosis was consistent with a schwannoma.Conclusion: Small cauda equina schwannomas involving ventral nerve roots can cause acute radiculopathy readily relieved with decompressive laminectomies for tumor excision.

Cerebrospinal Fluid-Venous Fistulas: A Systematic Review and Examination of Individual Patient Data.

Spontaneous intracranial hypotension (SIH) is usually caused by a spinal cerebrospinal fluid (CSF) leak. CSF-venous fistula is an underdiagnosed cause of spinal CSF leak, as it is challenging to identify on myelography. To review existing literature to summarize common presentations, diagnostic imaging modalities, and current treatment strategies for CSF-venous fistulas. We conducted a systematic review using PubMed, Embase, Scopus, and Web of Science databases to identify studies discussing CSF-venous fistulas. Titles and abstracts were screened. Studies meeting prespecified inclusion criteria were reviewed in full. Of 180 articles identified, 16 articles met inclusion criteria. Individual patient data was acquired from 7 studies reporting on 18 patients. CSF-venous fistula most frequently presented as positional headache. Digital subtraction myelography provided greatest detection of CSF-venous fistula in the lateral decubitus position and detected CSF-venous fistula in all individual patient cases. Dynamic computed tomography (CT) myelogram enabled detection and differentiation of CSF-venous fistulas from low-flow epidural leaks. The majority of fistulas were in the thoracic spine and slightly more common on the right. Epidural blood patch (EBP) provided temporary or no relief in all individual patients. Resolution or improvement of clinical symptoms and radiologic normalization were observed in all surgically treated patients. Although rare, CSF-venous fistula is an important cause of spinal CSF leak contributing to SIH. Dynamic CT myelogram and digital subtraction myelography, particularly in the lateral decubitus position, are the most accurate and effective diagnostic imaging modalities. EBPs often provide only transient relief, while surgical management is preferred.

A comparative study between high-definition volumetric imaging computed tomography and multi-slice computed tomography in the detection of acute thoraco-lumbar disc extrusions in dogs

Computed tomography (CT) is commonly used to image intervertebral disc extrusion (IVDE) in dogs. The current gold standard for CT imaging is the use of multi-slice CT (MS CT) units. Smaller high-definition volumetric imaging (HDVI) mobile CT has been marketed for veterinary practice. This unit is described as an advanced flat panel. The goal of this manuscript was to evaluate the ability of the HDVI CT in detecting IVDE without the need for CT myelography, compared with the detection of acute disc extrusions with a MS CT without the need for MS CT myelogram. Retrospective blinded analyses of 219 dogs presented for thoraco-lumbar IVDE that had a HDVI CT (n = 123) or MS CT (n = 96) were performed at a single referral hospital. A total of 123 cases had HDVI CT scans with surgically confirmed IVDE. The IVDE was identified in 88/123 (72%) dogs on pre-contrast HDVI CT. The remaining 35/128 (28%) cases required a HDVI CT myelogram to identify the IVDE. Ninety-six cases had MS CT scans with surgically confirmed IVDE. The IVDE was identified in 78/96 (81%) dogs on the pre-contrast MS CT. The remaining 18/96 (19%) cases had a MS CT myelogram to identify the IVDE. Multi-slice CT detected IVDE significantly more than HDVI CT (p = 0.032). This study showed that the ability of HDVI CT for detecting IVDE is lower than that of MS CT. The HDVI CT system may be useful in smaller referral practices, with a lower case load where space is limited.

Rapid Cognitive Decline Secondary to CSF Venous Fistula With Postoperative Rebound Intracranial Hypertension and a Hyperintense Paraspinal Vein Sign Seen Retrospectively.

A 56-year-old female with 2 prior Chiari decompressions presented with rapidly progressive cognitive decline. Brain magnetic resonance imaging, computed tomography myelogram, and prone digital subtraction myelography revealed signs of brain sag and left T9 perineural cysts but no cerebrospinal fluid leaks. Symptoms improved after multilevel blood patches but recurred. Lateral decubitus digital subtraction myelography revealed a spinal cerebrospinal fluid venous fistula (SCVF), which resolved after neurosurgeons ligated the nerve root. Rebound headaches with papilledema occurred on postoperative day 9 and then resolved 2months after acetazolamide was started. A hyperintense paraspinal vein was seen retrospectively on T2-weighted magnetic resonance imaging with Dixon fat suppression sequencing. This case is unique in the acuity of cognitive decline secondary to SCVF. Acetazolamide at the time of treatment may potentially be used as prophylaxis for rebound intracranial hypertension. The hyperintense paraspinal vein may have utility in future diagnosis of SCVF.

Spinal cerebrospinal fluid leak in the context of pars interarticularis fracture

BackgroundSpinal cerebrospinal fluid (CSF) leak can lead to intracranial hypotension and is an important differential diagnosis to consider in patients with sudden-onset chronic daily headaches. Pars interarticularis (PI) fracture is a potential rare cause of suspected spinal CSF leak.MethodsThis is a retrospective case series of 6 patients with suspected spinal CSF leak evaluated between January 2016 and September 2019. All patients received a magnetic resonance imaging (MRI) of the brain with and without gadolinium, MRI whole spine and full spine computed tomography (CT) myelogram. Targeted epidural patches with fibrin sealant were performed. Treatment response at return visit (3 months post-patch) was documented.ResultsSix patients (4 females, 2 males) were diagnosed with a suspected spinal CSF leak and PI fracture. Mean age at the time of headache onset was 39 years old, and a range from 32 to 50 years old. Mean time to targeted epidural patches with fibrin sealant was 4.5 years. All 6 patients had PI fractures identified on CT myelogram and received targeted epidural patches with fibrin sealant at the site of the PI fracture. All patients had significant improvement in their headache intensity.ConclusionOur study highlights: 1) the importance of PI fracture as a possible culprit of suspected spinal CSF leak in patients with intracranial hypotension; 2) the added benefit of CT imaging for detecting bony abnormalities such as fractures in patients with intracranial hypotension; and 3) the successful treatment of suspected spinal CSF leak when targeting the fracture site.