Additional Diagnostic Value of Conebeam CT Myelography Performed after Digital Subtraction Myelography for Detecting CSF-Venous Fistulas
========================================================================================================================================

* Ajay A. Madhavan
* Niklas Lutzen
* Jeremy K. Cutsforth-Gregory
* Wouter I. Schievink
* Michelle L. Kodet
* Ian T. Mark
* Pearse P. Morris
* Steven A. Messina
* John T. Wald
* Waleed Brinjikji

## Graphical Abstract

![Figure1](http://www.ajnr.org/https://ajnr-sso.highwirestaging.com/content/ajnr/46/5/1044/F1.medium.gif)

[Figure1](http://www.ajnr.org/content/46/5/1044/F1)

## Abstract

**BACKGROUND AND PURPOSE:** CSF-venous fistulas (CVFs) are a common cause of spontaneous intracranial hypotension. The diagnosis and precise localization of these fistulas hinges on specialized myelographic techniques, which mainly include decubitus digital subtraction myelography and decubitus CT myelography (by using either energy-integrating or photon-counting detector CT). A previous case series showed that conebeam CT myelography (CB-CTM), performed as an adjunctive tool with digital subtraction myelography, increased the detection of CVFs. Here, we sought to determine the additive yield of CB-CTM for CVF detection in a consecutive series of patients with spontaneous intracranial hypotension who underwent concurrent decubitus digital subtraction myelography and CB-CTM.

**MATERIALS AND METHODS:** We retrospectively searched our institutional database for all consecutive patients who underwent decubitus digital subtraction myelography with adjunctive CB-CTM between August 5, 2021 and August 5, 2024. We excluded any patients harboring extradural CSF on spine imaging, not meeting International Classification of Headache Disorders, 3rd edition criteria for spontaneous intracranial hypotension, or not having undergone technically successful CB-CTM in combination with digital subtraction myelography. All myelographic images were independently reviewed by 2 neuroradiologists. We calculated the diagnostic yield of both myelographic tests for localizing a CVF.

**RESULTS:** We identified 100 patients who underwent decubitus digital subtraction myelography with adjunctive conebeam CT. We excluded 15 patients based on above criteria. Fifty-nine of 85 patients had a single definitive CVF. Among positive cases, the fistula was visible on digital subtraction myelography in 38 of 59 patients and visible on CB-CTM in 59 of 59 patients. In 26 of 85 patients, no definitive fistula was identified by either technique.

**CONCLUSIONS:** CB-CTM increased the diagnostic yield for CVF detection and may be a useful addition to digital subtraction myelography.

## ABBREVIATIONS:

AP
:   anterior-posterior
CB-CTM
:   conebeam CT myelography
CVF
:   CSF-venous fistula
DSM
:   digital subtraction myelography
ICHD-3
:   International Classification of Headache Disorders, 3rd edition
PCD-CTM
:   photon-counting detector CT myelography
SIH
:   spontaneous intracranial hypotension

SUMMARY

#### PREVIOUS LITERATURE:

Previous studies have described the use of CB-CTM to aid in the detection of CVFs, a common cause of spontaneous intracranial hypotension. The additional diagnostic value of this technique has not previously been studied in a large patient cohort.

#### KEY FINDINGS:

The combined diagnostic yield for digital subtraction myelography and CB-CTM, on a per-patient basis, was 59 of 85. CB-CTM provided an incremental yield for CVF detection in 21 of 59 patients, whose fistulas were identified only on CB-CTM.

#### KNOWLEDGE ADVANCEMENT:

The detection of CVFs remains challenging, despite many recent advancements in myelographic techniques. CB-CTM represents a potentially valuable adjunctive technique to digital subtraction myelography.

Spontaneous intracranial hypotension (SIH) is usually caused by a spinal CSF leak. Although SIH has many clinical manifestations, the hallmark symptom is an orthostatic headache. Various etiologies for spontaneous spinal CSF leaks have been described, including ventral dural tears, lateral dural tears, slow leaks from meningeal diverticula, and CSF-venous fistulas (CVFs).1⇓–3 Skull base CSF leaks do not typically result in SIH.4 CVFs are the most recently recognized cause of SIH and oftentimes are the most challenging to diagnose. Unlike patients with dural tears, those with CVFs essentially never have extradural CSF on spine MRI or other imaging, with the main exception being rare patients with more than 1 type of concurrent spinal CSF leak.5,6 Furthermore, some patients with CVFs may have a normal brain MRI, causing the diagnosis to be overlooked. The increased use of decubitus myelography has been instrumental in increasing the diagnostic yield for CVF detection, permitting targeted treatment through surgery, transvenous fistula embolization, or transforaminal fibrin glue occlusion.7⇓⇓–10

Decubitus myelography for CVF detection can be performed by using a variety of techniques, including digital subtraction myelography (DSM), traditional energy-integrating detector CT myelography, or photon-counting detector CT myelography (PCD-CTM). All these modalities offer unique advantages and disadvantages, and DSM has greater temporal resolution than any CT-based technique.11⇓⇓⇓⇓–16 Conebeam CT myelography (CB-CTM) has been described as an adjunctive technique after DSM to detect or improve characterization of CVFs. In a prior study of 3 patients, CB-CTM detected CVFs that were occult on DSM.17,18 We hypothesized that CB-CTM performed after DSM may provide a positive incremental yield for detection of CVFs. In this retrospective study, we sought to determine the added yield of CB-CTM for CVF detection in a large cohort of patients who underwent both examinations on the same day.

## MATERIALS AND METHODS

### Patient Selection

Patient consent was waived by our institutional review board. A standard Strengthening the Reporting of Observational Studies in Epidemiology checklist was used to assist in appropriate study design (Supplemental Data). We performed a retrospective review of our radiologic database to identify all consecutive patients who underwent bilateral decubitus DSM followed by CB-CTM (1 side per day) between August 5, 2021 and August 5, 2024. We excluded patients if they 1) did not meet International Classification of Headache Disorders, 3rd edition (ICHD-3) criteria for SIH, 2) had extradural CSF on spine MRI, 3) had a technically unsuccessful examination (due to inadvertent subdural injections or lack of patient tolerance), or 4) did not undergo preprocedural brain MRI with and without IV contrast.

### Brain MRI Review

Preprocedural brain MRIs in all patients were reviewed independently by 2 neuroradiologists to assess for findings of SIH (specifically, brain sagging, venous sinus distention, dural enhancement, pituitary engorgement, or atraumatic subdural fluid collections). Pituitary engorgement was defined by a convex superior margin of the gland; the remaining features were subjectively assessed based on the radiologists’ experience. Brain MRIs were dichotomously rated as positive if they had at least 1 of the aforementioned markers of SIH and negative if they lacked all 5. Any disagreement between the initial 2 neuroradiologists was resolved through independent review by a third adjudicating neuroradiologist. The neuroradiologists involved in imaging review were all board certified, routinely interpret brain MRIs and perform myelography for patients with SIH, and had postfellowship practice experience ranging from 3–25 years. All reviewers were blinded to imaging reports.

### Myelographic Technique

The precise technique for DSM and CB-CTM has previously been described.7 Briefly, patients are placed in the decubitus position on a fluoroscopy table, by using a wedge to elevate their lumbar spine. The examination is performed with either no sedation or awake moderate sedation (by using IV fentanyl and midazolam) depending on patient preference. Our institution currently uses the ARTIS icono angiography system (Siemens Healthineers). Lumbar puncture is performed at L2–L3 or below by using a 20- or 22-gauge spinal needle. The flat panel detector is centered over the upper thoracic spine to obtain a single plane anterior-posterior (AP) view, usually covering at least C7–T11. Single AP plane DSM is performed at 1 frame per second during injection of 6 mL Omnipaque 300 (GE Healthcare), imaging for at least 60 seconds. The process is repeated after repositioning the detector to cover the lower thoracic and upper lumbar spine.

View this table:
[Table1](http://www.ajnr.org/content/46/5/1044/T1)

Number of CVFs observed at different spinal levels in our study cohort

CBCT has a limited z-axis range, usually covering approximately 6 vertebral levels. To determine the field-of-view for CB-CTM, DSM images are immediately reviewed in the fluoroscopy room to assess for 1 of the following: a definitive CVF, indeterminate findings potentially suggesting a CVF (flickering densities or rapidly emptying diverticula19), or any large or irregular diverticula that may harbor a CVF. Even if a definitive CVF is seen, CB-CTM is still performed to provide superior anatomic characterization of the fistula, which is helpful for treatment planning (Fig 1). If the DSM looks entirely unremarkable without evidence of meningeal diverticula, CB-CTM is typically not performed, though this depends on radiologist preference. After centering the flat panel detector over the level(s) of greatest interest, an additional 4–6 mL of Omnipaque 300 are injected under direct fluoroscopic visualization. As soon as contrast ascends and sufficiently coats the lateral thecal sac, the CBCT is obtained with a breath hold during full inspiration. Specific CBCT settings can be modulated to balance image quality and radiation dose. We use a 200° rotation over a 5-second period, with an image obtained every 0.5°. The final data set is reconstructed at a section thickness of 0.2 mm.

![FIG 1.](http://www.ajnr.org/https://ajnr-sso.highwirestaging.com/content/ajnr/46/5/1044/F2.medium.gif)

[FIG 1.](http://www.ajnr.org/content/46/5/1044/F2)

FIG 1. 
Superior anatomic characterization of a CVF by using CB-CTM. Right decubitus DSM (*A*) demonstrates a clear right T2 CVF arising from a meningeal diverticulum (*A*, *arrowhead*) involving the external vertebral venous plexus (*A*, *arrows*). CB-CTM performed immediately afterward (*B*) shows the same fistula arising from the right T2 meningeal diverticulum (*B*, *arrowhead*) with involvement of the ipsilateral external vertebral venous plexus (*B*, *solid arrows*) and additional prominent involvement of the ventral internal epidural venous plexus, crossing midline into the contralateral venous system (*B*, *dashed arrows*).

### Myelography Review and Diagnostic Yield Calculation

All decubitus DSMs and CB-CTMs were independently reviewed by the same 2 neuroradiologists. DSMs and CB-CTMs were reviewed in separate sessions spaced apart by 2 weeks. For each examination, the reviewers recorded whether a definitive CVF was visible. Any discrepant findings between the 2 initial reviewers were resolved by the same aforementioned third adjudicating neuroradiologist.

The combined diagnostic yield of DSM with concurrent CB-CTM was calculated on a per-patient basis as the simple fraction of examinations positive for 1 or more CVFs. This combined yield was also calculated for the subset of patients with positive versus negative brain MRIs. Last, the individual diagnostic yield of DSM and CB-CTM was calculated on a per-patient basis.

DSM and CB-CTM images for patients whose CVFs were seen on only 1 of the 2 modalities were reviewed a second time by the initial 2 reviewing neuroradiologists in consensus to determine whether the CVF was visible on the initially “negative” technique in retrospect, and whether there was an identifiable reason why the CVF was only visible on 1 of the modalities.

## RESULTS

### Patient Cohort

We initially identified 100 patients who underwent bilateral decubitus DSM followed by CB-CTM. We excluded 15 patients (12 did not meet ICHD-3 criteria for SIH, and 3 did not undergo brain MRI with and without IV contrast). All 85 patients in the final cohort underwent bilateral DSM and bilateral CB-CTM. Forty-five of 85 (53.0%) of patients were women. Mean age was 58.2 years (range 19–85 years).

### Brain MRI Findings

In a single patient, 1 reviewer rated venous sinus distention to be present and the other deemed it absent. In this case, the third adjudicating reviewer rated venous sinus distention to be present. Outside of this, there was no disagreement between the 2 initial reviewers in brain MRI findings. Overall, 60 of 85 patients had a positive brain MRI harboring at least 1 finding compatible with SIH, and the remaining 25 of 85 patients had no brain MRI findings for SIH.

### Myelographic Findings

There were no disagreements between reviewers regarding DSM findings. In 1 patient’s CB-CTM, a CVF was initially only identified by 1 of 2 reviewers. The third adjudicating neuroradiologist deemed a CVF to be present on this examination. There were no other disagreements between the 2 initial reviewers on CB-CTM findings. Accounting for both DSM and CB-CTM findings, reviewers identified a single CVF in 59 of 85 patients. No patients had more than 1 CVF. The CVF was on the right side in 39 of 59 (66.1%) patients and on the left in the remaining patients. The Table lists the number of CVFs observed at different spinal levels. The single CVF seen at L2 was associated with a paraspinal venous malformation. The other CVFs had no associated paraspinal lesion.

### Diagnostic Yields of DSM and CB-CTM

The combined yield of DSM and CB-CTM was 59 of 85 (69.4%). Stratifying by brain MRI findings, the combined yield was 53 of 60 (88.3%) in patients with a positive brain MRI, and 6 of 25 (24.0%) in patients with a negative brain MRI.

Among cases in which a CVF was found, CB-CTM detected the CVF in 59 of 59 patients, whereas DSM detected the CVF in 38 of 59 patients. The overall diagnostic yield of CB-CTM was 59 of 85 (69.4%), and the diagnostic yield of DSM was 38 of 85 (44.6%). Therefore, CB-CTM had an incremental yield of 24.8%. There were no cases of CVFs seen on DSM and missed on CB-CTM.

### Additional Imaging Review

There were 21 cases in which a CVF was detected on CB-CTM and not identified on DSM. In 1 of 21 of these cases, the reviewers determined on secondary analysis that this CVF was likely visible on the initial DSM, albeit very subtle (Fig 2). In 20 of 21 patients, the CVF was not visible on DSM, even in retrospect. Note that 4 of 21 of these patients had a normal brain MRI. Among the 21 CVFs that were only apparent on CB-CTM, identifiable reasons for this included veins that overlapped large meningeal diverticula on the DSM (*n* = 6), subtle CVFs in the internal epidural venous plexus that were not visible on the DSM (*n* = 6), and intraosseous venous drainage that was not apparent on DSM (*n* = 4). For the remaining cases, it was not obvious why only CB-CTM identified the CVF.

![FIG 2.](http://www.ajnr.org/https://ajnr-sso.highwirestaging.com/content/ajnr/46/5/1044/F3.medium.gif)

[FIG 2.](http://www.ajnr.org/content/46/5/1044/F3)

FIG 2. 
Right T7 CVF that was initially deemed occult on DSM by both image reviewers but ultimately felt to be subtly present on secondary review after seeing CB-CTM findings. The CB-CTM (*A*) demonstrates a clear right T7 CVF (*A*, *arrows*) immediately anterior to a contrast-opacified meningeal diverticulum (*A*, *dashed arrow*). The DSM (*B*), performed during the same session, had shown a very subtle flickering attenuation over a few frames (*B*, *solid arrow*) adjacent to the diverticulum (*B*, *dashed arrow*).

## DISCUSSION

In this study, we sought to determine the additive diagnostic yield for CVF detection gained by performing CB-CTM immediately after DSM. We found that the individual diagnostic yields of DSM and CB-CTM were 44.6% and 69.4%, respectively. Thus, CB-CTM provided a positive incremental yield, identifying a CVF in an additional 24.8% of patients. Because CB-CTM can be conveniently performed after DSM without moving the patient, we believe it may represent a valuable additional tool for patients with suspected CVFs. Our findings are in keeping with a recent study by Lutzen et al,16 which similarly showed added value of performing decubitus CT myelography after DSM while leaving the spinal needle in place and injecting additional contrast for the second examination. CB-CTM has the additional advantage of not requiring the patient to be transported to a CT scanner with the needle in place, because the examination is performed in the fluoroscopy suite.

In our experience, CB-CTM after DSM is particularly helpful in certain key circumstances. First, CB-CTM can detect CVFs draining into the paraspinal segmental veins anterior to large meningeal diverticula (Fig 3). DSM often detects these CVFs as well, but they may be missed if the vein and diverticulum are superimposed on the AP view. Second, CB-CTM is effective in differentiating venous opacification from pulmonary markings, which can be challenging if respiratory motion occurs during DSM.17,18 Third, CB-CTM reliably detects subtle CVFs draining into the internal epidural venous plexus, which can be superimposed with intrathecal contrast or osseous structures on a DSM depending on imaging obliquity (Figs 3– 4). Fourth, CB-CTM can be useful to scrutinize diverticula that rapidly empty on DSM without a clear culprit CVF (Supplemental Data).19 Finally, CB-CTM may detect intraosseous CVF drainage that is not seen on DSM (Fig 5).

![FIG 3.](http://www.ajnr.org/https://ajnr-sso.highwirestaging.com/content/ajnr/46/5/1044/F4.medium.gif)

[FIG 3.](http://www.ajnr.org/content/46/5/1044/F4)

FIG 3. 
Example of a CVF not seen on DSM due to superimposition of a meningeal diverticulum and draining veins. Right decubitus DSM shows a prominent contrast-filled right T6 diverticulum (*A*, *dashed arrow*) with nothing for venous opacification. Axial images from right decubitus CB-CTM (*B* and *C*) performed immediately afterward show a clear right T6 CVF arising from the same diverticulum (*B*, *dashed arrow*) and involving the paraspinal segmental vein anterior to the diverticulum (*B*, *solid arrow*), as well as the ventral internal epidural venous plexus (*C*, *solid arrows*).

![FIG 4.](http://www.ajnr.org/https://ajnr-sso.highwirestaging.com/content/ajnr/46/5/1044/F5.medium.gif)

[FIG 4.](http://www.ajnr.org/content/46/5/1044/F5)

FIG 4. 
Example of a CVF not seen on DSM, presumably due to relatively subtle drainage into the internal epidural venous plexus. Unsubtracted image from right decubitus DSM (*A*) shows a small right T12 diverticulum (*A*, *dashed arrow*) with no evidence of CVF. Subsequent coronal (*B*) and sagittal images (*C*) from CB-CTM show the same diverticulum (*B* and *C*, *dashed arrows*) with a subtle CVF draining into the internal epidural venous plexus (*B* and *C*, *solid arrows*).

![FIG 5.](http://www.ajnr.org/https://ajnr-sso.highwirestaging.com/content/ajnr/46/5/1044/F6.medium.gif)

[FIG 5.](http://www.ajnr.org/content/46/5/1044/F6)

FIG 5. 
Intraosseous CVF not well seen on DSM but clearly demonstrated on CB-CTM. Left decubitus DSM (*A*) shows a prominent left T11 meningeal diverticulum (*A*, *dashed arrow*) without evidence of venous opacification. Sagittal (*B*) and coronal (*C*) images from subsequent CB-CTM show a CVF draining into the T11 lamina and pedicle (*B–C*, *solid arrows*), arising from a the same left T11 diverticulum (*B* and *C*, *dashed arrows*). There was also subtle involvement of the external vertebral venous plexus on the CB-CTM (*C*, *arrowheads*).

While CB-CTM is an excellent tool, there are some patients in whom DSM better characterizes CVFs, likely due to its higher temporal resolution and ability to image during different phases of respiration (Supplemental Data).20⇓–22 In cases in which venous opacification traverses different spinal levels, DSM may also more accurately determine the level at which the CVF originates due to its higher temporal resolution. In many cases, DSM and CB-CTM provide complementary information.

In the modern era, a wide variety of myelographic modalities are available for CVF localization.11,23 Each of these carries unique strengths and weaknesses. DSM has the greatest temporal resolution and has high spatial resolution. PCD-CTM and CB-CTM also have excellent spatial resolution, generally similar to that of DSM depending on the specific equipment used.24 Although CT-based techniques have less temporal resolution than DSM, they greatly benefit from the addition of cross-sectional detail, which is helpful to detect some CVFs. One drawback of CB-CTM is its limited field-of-view. However, since our technique mainly uses CB-CTM to further investigate equivocal or indeterminate findings on DSM, selecting the optimal z-axis coverage for CB-CTM is often straightforward. Ultimately, since only a subset of modalities is available to most practicing radiologists, dissemination of knowledge about the potential value of any of these techniques is helpful to patients with SIH who may have limited access or ability to travel to specialist centers.

We also found that the combination of DSM and CB-CTM had a diagnostic yield of 88.3% and 24.0% in patients with positive versus negative brain MRIs, respectively. The reported yield of decubitus myelography stratified by brain MRI findings continues to vary widely in the literature, likely in part due to differences in myelographic technique and patient selection used in prior studies.13,25,26 For this study, we intentionally rated brain MRIs in a dichotomous fashion rather than relying on brain MRI scoring systems, such as the Bern score.27 Such scoring systems are clinically useful, but they have limitations in discriminating positive and negative brain MRIs. For example, an examination with diffuse pachymeningeal enhancement but no other abnormalities would be placed in the same “low probability” category as an entirely normal examination. It is also important to note that we focused on the most classic brain MRI findings of SIH, but other abnormalities, such as loss of perioptic CSF, have been described with this disease as well.28 Our approach is in keeping with a recent study assessing the yield of decubitus CTM in patients with a positive versus negative brain MRI.29 The primary purpose of our study was not to stratify diagnostic yield by brain MRI findings, but it nonetheless remains important to highlight that CVFs can occasionally be observed in patients with a normal brain MRI.30

Our study has limitations. First, it is important to note that our conclusions are specific to our particular technique for performing DSM. We perform DSM by using a single-plane technique without the aid of general anesthesia. The yield of biplane DSM with general anesthesia, as performed at some institutions, is likely higher than in our study.7 Second, it is not possible to control for some variables between DSM and CB-CTM. For example, additional contrast was injected between the DSM and CB-CTM in these patients, which could account for some of the incremental yield of the latter test since this increases contrast attenuation within meningeal diverticula and theoretically pressurizes the subarachnoid space. Notably, our technique does generally require intrathecal administration of over 3 g of iodine, but there is increasing evidence in the literature that this is safe and well-tolerated.25

## CONCLUSIONS

CB-CTM is a valuable adjunct to DSM for the detection of CVFs, having demonstrated a positive incremental yield in our study cohort. Going forward, techniques can likely be optimized further. For instance, a higher resolution technique by using a 14-second acquisition has been described, which can provide superior image quality at the cost of a longer scan length and smaller field-of-view (Fig 6).31 This technique may further increase the additive yield of CB-CTM. Continued clinical application and research into CB-CTM will be helpful to better understand its potential in this patient population.

![FIG 6.](http://www.ajnr.org/https://ajnr-sso.highwirestaging.com/content/ajnr/46/5/1044/F7.medium.gif)

[FIG 6.](http://www.ajnr.org/content/46/5/1044/F7)

FIG 6. 
Demonstration of a CVF by using ultra-high-resolution CB-CTM, providing 0.14-mm spatial resolution in a 14-second acquisition. The fistula originates at T7 on the right (*A*, *solid white arrows*) and ascends via the internal epidural venous plexus to a higher spinal level (*A*, *dashed white arrows*). Axial view reveals the fistula’s drainage into dorsal muscular branches at T7 (*B*, *solid white arrows*). After surgical ligation, follow-up MRI of the head showed complete resolution of initial marked SIH signs, including bilateral subdural hematomas (not shown). Images provided by Dr. Niklas Lützen, CSF Center Freiburg, University Medical Center Freiburg, Germany.

## Footnotes

*   [Disclosure forms](https://www.ajnr.org/sites/default/files/additional-assets/Disclosures/May%202025/0948.pdf) provided by the authors are available with the full text and PDF of this article at [www.ajnr.org](http://www.ajnr.org).

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    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTE6Im5ldXJpbnRzdXJnIjtzOjU6InJlc2lkIjtzOjEwOiIxNi8xMi8xMjU2IjtzOjQ6ImF0b20iO3M6MjA6Ii9ham5yLzQ2LzUvMTA0NC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

9.  9.Callen AL, Jones LC, Timpone VM, et al. Factors predictive of treatment success in CT-guided fibrin occlusion of CSF-venous fistulas: a multicenter retrospective cross-sectional study. AJNR Am J Neuroradiol 2023;44:1332–38 doi:10.3174/ajnr.A8005 pmid:37798111
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czoxMDoiNDQvMTEvMTMzMiI7czo0OiJhdG9tIjtzOjIwOiIvYWpuci80Ni81LzEwNDQuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

10. 10.Callen AL, Timpone VM, Schwertner A, et al. Algorithmic multimodality approach to diagnosis and treatment of spinal CSF leak and venous fistula in patients with spontaneous intracranial hypotension. AJR Am J Roentgenol 2022;219:292–301 doi:10.2214/AJR.22.27485 pmid:35261281
    
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11. 11.Madhavan AA, Brinjikji W, Cutsforth-Gregory JK, et al. Myelographic techniques for the localization of CSF-venous fistulas: updates in 2024. AJNR Am J Neuroradiol 2024;45:1403–12 doi:10.3174/ajnr.A8299 pmid:39089875
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czoxMDoiNDUvMTAvMTQwMyI7czo0OiJhdG9tIjtzOjIwOiIvYWpuci80Ni81LzEwNDQuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

12. 12.Madhavan AA, Yu L, Brinjikji W, et al. Utility of photon-counting detector CT myelography for the detection of CSF-venous fistulas. AJNR Am J Neuroradiol 2023;44:740–44 doi:10.3174/ajnr.A7887 pmid:37202116
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiI0NC82Lzc0MCI7czo0OiJhdG9tIjtzOjIwOiIvYWpuci80Ni81LzEwNDQuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

13. 13.Madhavan AA, Cutsforth-Gregory JK, Brinjikji W, et al. Diagnostic performance of decubitus photon-counting detector CT myelography for the detection of CSF-venous fistulas. AJNR Am J Neuroradiol 2023;44:1445–50 doi:10.3174/ajnr.A8040 pmid:37945523
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czoxMDoiNDQvMTIvMTQ0NSI7czo0OiJhdG9tIjtzOjIwOiIvYWpuci80Ni81LzEwNDQuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

14. 14.Schwartz FR, Kranz PG, Malinzak MD, et al. Myelography using energy-integrating detector CT versus photon-counting detector CT for detection of CSF-venous fistulas in patients with spontaneous intracranial hypotension. AJR Am J Roentgenol 2024;222:e2330673 doi:10.2214/AJR.23.30673 pmid:38294163
    
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    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo3OiI0Mi8xLzMyIjtzOjQ6ImF0b20iO3M6MjA6Ii9ham5yLzQ2LzUvMTA0NC5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

16. 16.Lutzen N, Demerath T, Wurtemberger U, et al. Direct comparison of digital subtraction myelography versus CT myelography in lateral decubitus position: evaluation of diagnostic yield for cerebrospinal fluid-venous fistulas. J Neurointerv Surg 2023;16:1060–65
    
    

17. 17.Madhavan AA, Cutsforth-Gregory JK, Benson JC, et al. Conebeam CT as an adjunct to digital subtraction myelography for detection of CSF-venous fistulas. AJNR Am J Neuroradiol 2023;44:347–50 doi:10.3174/ajnr.A7794 pmid:36759140
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiI0NC8zLzM0NyI7czo0OiJhdG9tIjtzOjIwOiIvYWpuci80Ni81LzEwNDQuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

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    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czoxMDoiNDUvMTEvMTYxMyI7czo0OiJhdG9tIjtzOjIwOiIvYWpuci80Ni81LzEwNDQuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

19. 19.Akkipeddi SMK, Ellens N, Singh R, et al. “Empty cyst sign” appearance of CSF-venous fistula on digital spinal myelography. World Neurosurg 2024;188:78 doi:10.1016/j.wneu.2024.04.078 pmid:38663740
    
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    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiI0MS85LzE3NTQiO3M6NDoiYXRvbSI7czoyMDoiL2FqbnIvNDYvNS8xMDQ0LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

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25. 25.Edelmuth DGL, Leao RV, Filho EN, et al. Safety and technical performance of bilateral decubitus CT myelography using standard versus increased intrathecal iodinated contrast volume. AJNR Am J Neuroradiol Epub ahead of print August 12, 2024 doi:10.3174/ajnr.A8436
    
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26. 26.Huynh TJ, Parizadeh D, Ahmed AK, et al. Lateral decubitus dynamic CT myelography with real-time bolus tracking (dCTM-BT) for evaluation of CSF-venous fistulas: diagnostic yield stratified by brain imaging findings. AJNR Am J Neuroradiol 2023;45:105–12 doi:10.3174/ajnr.A8082 pmid:38164531
    
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31. 31.Lutzen N, Beck J, Urbach H. Cerebrospinal fluid venous fistula imaging with ultrahigh-resolution cone-beam computed tomography. JAMA Neurol 2023;80:870–71 doi:10.1001/jamaneurol.2023.1640 pmid:37306975
    
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*   Received September 24, 2024.
*   Accepted after revision October 10, 2024.


*   © 2025 by American Journal of Neuroradiology