Abstracts 2020

Schievink WI, Maya M, Prasad RS, Wadhwa VS, Cruz RB, Moser FG.
AJNR Am J Neuroradiol. 2020 Dec 17. doi: 10.3174/ajnr.A6895. Online ahead of print.
Abstract
Background and purpose: Spinal CSF-venous fistulas are increasingly recognized as the cause of spontaneous intracranial hypotension. Here, we describe the challenges in the care of patients with CSF-venous fistulas who are morbidly or super obese.
Materials and methods: A review was undertaken of all patients with spontaneous intracranial hypotension and a body mass index of >40 who underwent digital subtraction myelography in the lateral decubitus position to look for CSF-venous fistulas.
Results: Eight patients with spontaneous intracranial hypotension with a body mass index of >40 underwent lateral decubitus digital subtraction myelography. The mean age of these 5 women and 3 men was 53 years (range, 45 to 68 years). Six patients were morbidly obese (body mass indexes = 40.2, 40.6, 41, 41.8, 45.4, and 46.9), and 2 were super obese (body mass indexes = 53.7 and 56.3). Lumbar puncture showed an elevated opening pressure in 5 patients (26.5-47 cm H₂O). The combination of an elevated opening pressure and normal conventional spine imaging findings resulted in a misdiagnosis (midbrain glioma and demyelinating disease, respectively) in 2 patients. Prior treatment included surgical nerve root ligation for suspected CSF-venous fistula in 3 patients. Digital subtraction myelography demonstrated a CSF-venous fistula in 6 patients (75%). Rebound high-pressure headache occurred in all 6 patients following surgical ligation of the fistula, and papilledema developed in 3.
Conclusions: In our series, opening pressure was generally elevated in patients with morbid or super obesity. The yield of identifying CSF-venous fistulas with digital subtraction myelography in this patient population can approach that of the nonobese patient population. These patients may be at higher risk of developing rebound high-pressure headaches and papilledema.
PMID: 33334852
DOI: 10.3174/ajnr.A6895

D’Amico D, Usai S, Chiapparini L, Erbetta A, Gioppo A, Messina G, Astengo A, Leone M.
Neurol Sci. 2020 Dec;41(Suppl 2):423-427.  doi: 10.1007/s10072-020-04642-9.
Abstract
Headache is the most common symptom of spontaneous intracranial hypotension (SIH). The present review focuses on data regarding headache features reported in the most relevant published articles and summarizes the main SIH headache features, namely, orthostatic headache, headache triggered by Valsalva maneuver, pattern of onset of headache, and location and quality of headache. Published data indicate that the clinical suspect of this disorder may be challenging, due to its protean presentation. Among the main implications for clinical practice, we suggest to suspect SIH in all patients with a new onset headache, as different forms of primary and secondary headache should be considered in the differential diagnosis of SIH, particularly cervicogenic headache, new daily persistent headache, and headaches precipitated by Valsalva maneuver. The clinical interview must include specific questions on the possible orthostatic feature of headache, although its absence should not make clinicians to reject the SIH hypothesis as headache cannot be orthostatic in each patient and in all periods of the natural history of the disease. Other disorders with orthostatic symptoms, such as in postural tachycardia syndrome (POTS) and persistent postural-perceptual dizziness (PPPD), should be considered in the differential diagnosis. Awareness that SIH can present with acute, sudden onset requires that clinicians working in the emergency settings should consider SIH in the range of diagnoses of thunderclap headache.
PMID: 33034803
DOI: 10.1007/s10072-020-04642-9

Pensato U, Russo C, Favoni V, Cirillo L, Asioli GM, Cortelli P, Cevoli S, Pierangeli G.
Neurol Sci. 2020 Dec;41(Suppl 2):475-477. doi: 10.1007/s10072-020-04664-3.
No abstract available.
PMID: 32845492 
DOI: 10.1007/s10072-020-04664-3

Johnson DR, Carr CM, Luetmer PH, Diehn FE, Lehman VT, Cutsforth-Gregory JK, Verdoorn JT, Krecke KN.
World Neurosurg. 2020 Nov 18:S1878-8750(20)32441-4. doi: 10.1016/j.wneu.2020.11.066. Online ahead of print.
Abstract
Background: Diagnosis of spontaneous intracranial hypotension (SIH) may be delayed due to nonspecific symptoms and variable imaging findings. Cases of hyperostosis in children who are overshunted, a process that may be physiologically analogous to adults with SIH, have been reported by others and observed in our practice. The purpose of this retrospective study was to assess the frequency and pattern of calvarial hyperostosis in patients with SIH.
Methods: We retrospectively reviewed computed tomography and magnetic resonance imaging examinations from consecutive patients who underwent myelography for the evaluation of SIH to assess for the presence of generalized calvarial thickening or development of a secondary layer of bone. Patients with typical benign hyperostosis frontalis were excluded. Patient demographics and clinical factors were evaluated for association with hyperostosis.
Results: Among 285 patients with SIH, 40 (14.0%) demonstrated diffuse calvarial hyperostosis on imaging. Most of these patients (32/40; 80.0%) demonstrated a distinct circumferentially layered appearance to the skull, whereas 8 of 40 (20.0%) had generalized calvarial thickening without layering.
Conclusions: Diffuse calvarial hyperostosis, particularly the concentrically layered form that we term “layer cake skull,” is a relatively common imaging feature in patients with SIH. In the appropriate clinical context, this finding will allow the possibility of SIH to be raised based on computed tomography imaging, which is otherwise of limited utility in the initial diagnosis of this condition.
PMID: 33220476 
DOI: 10.1016/j.wneu.2020.11.066

Matsuhashi A, Takai K, Taniguchi M.
J Neurosurg Spine. 2020 Nov 13:1-9. doi: 10.3171/2020.6.SPINE20487. Online ahead of print.
Abstract
Objective: Spontaneous spinal CSF leaks are caused by abnormalities of the spinal dura mater. Although most cases are treated conservatively or with an epidural blood patch, some intractable cases require neurosurgical treatment. However, previous reports are limited to a small number of cases. Preoperative detection and localization of spinal dural defects are difficult, and surgical repair of these defects is technically challenging. The authors present the anatomical characteristics of dural defects and surgical techniques in treating spontaneous CSF leaks.
Methods: Among the consecutive patients who were diagnosed with spontaneous CSF leaks at the authors’ institution between 2010 and 2020, those who required neurosurgical treatment were included in the study. All patients’ clinical information, radiological studies, surgical notes, and outcomes were reviewed retrospectively. Outcomes of two different procedures in repairing dural defects were compared.
Results: Among 77 patients diagnosed with spontaneous CSF leaks, 21 patients (15 men; mean age 57 years) underwent neurosurgery. Dural defects were detected by FIESTA MRI in 7 patients, by CT myelography in 12, by digital subtraction myelography in 1, and by dynamic CT myelography in 1. The spinal levels of the defects were localized at the cervicothoracic junction in 16 patients (76%) and thoracolumbar junction in 4 (19%). Intraoperative findings revealed that the dural defects were small, circumscribed longitudinal slits located at the ventral aspect of the dura mater. The median dural defect size was 5 × 2 mm. The presence of dural defects at the thoracolumbar junction was associated with manifestation of an altered mental status, which was an unusual manifestation of CSF leaks (p = 0.003). Eight patients were treated via the posterior transdural approach with watertight primary sutures of the ventral defects, and 13 were treated with muscle or fat grafting. Regardless of the two different procedures, postoperative MRI showed either complete disappearance or significant reduction of the extradural CSF collection. No patient experienced postoperative neurological deficits. Clinical symptoms improved or stabilized in 20 patients with a median follow-up of 12 months.
Conclusions: Dural defects in spontaneous CSF leaks were small, circumscribed longitudinal slits located ventral to the spinal cord at either the cervicothoracic or thoracolumbar junction. Muscle/fat grafting may be an alternative treatment to watertight primary sutures of ventral dural defects with a good outcome.
PMID: 33186904 
DOI: 10.3171/2020.6.SPINE20487

Dobrocky T, Rebsamen M, Rummel C, Häni L, Mordasini P, Raabe A, Ulrich CT, Gralla J, Piechowiak EI, Beck J.
AJNR Am J Neuroradiol. 2020 Nov;41(11):2055-2061. doi: 10.3174/ajnr.A6782.
Abstract
Background and purpose: CSF loss in spontaneous intracranial hypotension disrupts a well-regulated equilibrium. We aimed to evaluate the volume shift between intracranial compartments in patients with spontaneous intracranial hypotension before and after surgical closure of the underlying spinal dural breach.
Materials and methods: In total, 19 patients with spontaneous intracranial hypotension with a proved spinal CSF leak investigated at our institution between July 2014 and March 2017 (mean age, 41.8 years; 13 women) were included. Brain MR imaging-based volumetry at baseline and after surgery was performed with FreeSurfer. In addition, the spontaneous intracranial hypotension score, ranging from 0 to 9, with 0 indicating very low and 9 very high probability of spinal CSF loss, was calculated.
Results: Total mean ventricular CSF volume significantly increased from baseline (15.3 mL) to posttreatment MR imaging (18.0 mL), resulting in a mean absolute and relative difference, +2.7 mL and +18.8% (95% CI, +1.2 to +3.9 mL; P < .001). The change was apparent in the early follow-up (mean, 4 days). No significant change in mean total brain volume was observed (1136.9 versus 1133.1 mL, P = .58). The mean spontaneous intracranial hypotension score decreased from 6.9 ± 1.5 at baseline to 2.9 ± 1.5 postoperatively.
Conclusions: Our study demonstrated a substantial increase in ventricular CSF volume in the early follow-up after surgical closure of the underlying spinal dural breach and may provide a causal link between spinal CSF loss and spontaneous intracranial hypotension. The concomitant decrease in the spontaneous intracranial hypotension score postoperatively implies the restoration of an equilibrium within the CSF compartment.
PMID: 33177057 
PMCID: PMC7658827 (available on 2021-11-01) 
DOI: 10.3174/ajnr.A6782

Middlebrooks EH, Okromelidze L, Vilanilam GK, Gopal N, Luetmer PH, Gupta V.
World Neurosurg. 2020 Nov;143:e268-e274. doi: 10.1016/j.wneu.2020.07.108. Epub 2020 Jul 23.
Abstract
Objective: Syrinx development in patients with spontaneous intracranial hypotension (SIH) has rarely been described. To better understand this entity, we compared the clinical and radiographic findings in a series of patients with SIH and acquired Chiari-like tonsillar herniation with and without syrinx formation.
Methods: Six patients with syrinx in the setting of SIH and Chiari-like tonsillar herniation were retrospectively identified. The clinical and radiographic findings and outcomes were compared with those from a control group of patients with SIH and Chiari-like tonsillar herniation without syrinx.
Results: The patients with SIH and syrinx had had a higher opening pressure than had the control group (mean, 14.0 cm H₂O vs. 7.4 cm H₂O; P = 0.02) and a higher body mass index (mean, 33 kg/m² vs. 26 kg/m²; P = 0.01). The patients with syrinx had had an average obex displacement of 3.7 ± 2.2 mm below the plane of the foramen magnum compared with a position of 1.9 ± 3.1 mm above the plane of the foramen magnum in the control group (P = 0.004). The mean tonsillar descent was 12.7 ± 4.7 mm below the foramen magnum in those with syrinx compared with 5.9 ± 2.5 in the control group (P = 0.009). The clinical symptoms had improved in 83.3% of the patients with syrinx and 75% of the control patients after spinal cerebrospinal fluid leak closure. Three patients (50%) also had radiographic syrinx reduction.
Conclusion: Our results have shown that SIH can be an underrecognized cause of syrinx with key differences in body habitus and obex displacement compared with SIH without syrinx. In patients with tonsillar herniation into the foramen magnum associated with syrinx, the presence of SIH should be considered to avoid unnecessary foramen magnum decompression, even in those with a normal opening pressure.
PMID: 32711143
DOI: 10.1016/j.wneu.2020.07.108

Mamlouk MD, Ochi RP, Jun P, Shen PY.
AJNR Am J Neuroradiol. 2020 Oct 29. doi: 10.3174/ajnr.A6844. Online ahead of print.
Abstract
Decubitus CT myelography is a reported method to identify CSF-venous fistulas in patients with spontaneous intracranial hypotension. One of the main advantages of decubitus CT myelography in detecting CSF-venous fistulas is using gravity to dependently opacify the CSF-venous fistula, which can be missed on traditional myelographic techniques. Most of the CSF-venous fistulas in the literature have been identified in patients receiving general anesthesia and digital subtraction myelography, a technique that is not performed at all institutions. In this article, we discuss the decubitus CT myelography technique and how to implement it in daily practice.
PMID: 33122215
DOI: 10.3174/ajnr.A6844

Pope MC, Carr CM, Brinjikji W, Kim DK.
AJNR Am J Neuroradiol. 2020 Oct;41(10):1953-1957. doi: 10.3174/ajnr.A6765. Epub 2020 Sep 3.
Abstract
Background and purpose: Digital subtraction myelography performed with the patient in the lateral decubitus position has the potential for increased sensitivity over prone-position myelography in the detection of spinal CSF-venous fistulas, a well-established cause of spontaneous intracranial hypotension. We report on the safety of performing routine, consecutive-day right and left lateral decubitus digital subtraction myelography in these patients.
Materials and methods: In this retrospective case series, all patients undergoing consecutive-day lateral decubitus digital subtraction myelography for suspected spinal CSF leak between September 2018 and September 2019 were identified. Chart review was performed to identify any immediate or delayed adverse effects associated with the procedures. Procedural parameters were also analyzed due to inherent variations associated with the positive-pressure myelography technique that was used.
Results: A total of 60 patients underwent 68 pairs of consecutive-day lateral decubitus digital subtraction myelographic examinations during the study period. No major adverse effects were recorded. Various minor adverse effects were observed, including pain requiring analgesics (27.2%), nausea/vomiting requiring antiemetics (8.1%), and transient neurologic effects such as syncope, vertigo, altered mental status, and autonomic dysfunction (5.1%). Minor transient neurologic effects were correlated with increasing volumes of intrathecal saline injectate used for thecal sac prepressurization.
Conclusions: In patients with spontaneous intracranial hypotension and suspected spontaneous spinal CSF leak, consecutive-day lateral decubitus digital subtraction myelography demonstrates an acceptable risk profile without evidence of neurotoxic effects from cumulative intrathecal contrast doses. Higher intrathecal saline injectate volumes may correlate with an increased incidence of minor transient periprocedural neurologic effects.
PMID: 32883671 
PMCID: PMC7661090 (available on 2021-10-01) 
DOI: 10.3174/ajnr.A6765

Ferrante E, Trimboli M, Petrecca G, Allegrini F, Ferrante MM, Rubino F.
Headache. 2020 Sep;60(8):1777-1787. doi: 10.1111/head.13942. Epub 2020 Aug 30.
Abstract
Background: Spontaneous intracranial hypotension (SIH) is a rare condition resulting from cerebrospinal fluid (CSF) volume depletion, nearly always from spontaneous CSF leaks. CSF pressure in SIH is usually normal; low CSF pressure is found in a substantial minority of patients. SIH is uncommonly described in pregnancy.
Case series: Five women with SIH during pregnancy have been conservatively treated adopting bed rest and overhydration. After prolonged conservative treatment, only 1 patient showed complete symptoms resolution. A rare SIH complication as cerebral venous thrombosis has been reported in 1 case. All 4 remaining patients had lumbar epidural blood patch (EBP) with symptoms disappearance.
Conclusions: EBP might be proposed to SIH patients also during pregnancy and after a brief period (~10 days) of ineffective conservative treatment, because it could allow faster symptoms improvement and complete recovery. Furthermore, EBP would avoid prolonged bed rest with the risk of SIH severe complications.
PMID: 32862459 
DOI: 10.1111/head.13942

Wu JW, Wang YF, Hseu SS, Chen ST, Chen YL, Wu YT, Chen SP, Lirng JF, Wang SJ.
Cephalalgia. 2020 Aug 26:333102420950385. doi: 10.1177/0333102420950385. Online ahead of print.
Abstract
Objectives: In the application of the Monro-Kellie doctrine in spontaneous intracranial hypotension, the brain tissue volume is generally considered as a fixed constant. Traditionally, cerebral venous dilation is thought to compensate for decreased cerebrospinal fluid. However, whether brain tissue volume is invariable has not yet been explored. The objective of this study is to evaluate whether brain tissue volume is fixed or variable in spontaneous intracranial hypotension patients using automatic quantitative methods.
Methods: This retrospective and longitudinal study analyzed spontaneous intracranial hypotension patients between 1 January 2007 and 31 July 2015. Voxel-based morphometry was used to examine brain volume changes during and after the resolution of spontaneous intracranial hypotension. Brain structure volume was analyzed using Statistical Parametric Mapping version 12 and FMRIB Software Library v6.0. Post-treatment neuroimages were used as surrogate baseline measures.
Results: Forty-four patients with spontaneous intracranial hypotension were analyzed (mean age, 37.8 [8.5] years; 32 female and 12 male). The whole brain tissue volume was decreased during spontaneous intracranial hypotension compared to follow-up (1180.3 [103.5] mL vs. 1190.4 [93.1] mL, difference: -10.1 mL [95% confidence interval: -18.4 to -1.8 mL], p = 0.019). In addition, ventricular cerebrospinal fluid volume was decreased during spontaneous intracranial hypotension compared to follow-up (15.8 [6.1] mL vs. 18.9 [6.9] mL, difference: -3.2 mL [95% confidence interval: -4.5 to -1.8 mL], p < 0.001). Longer anterior epidural cerebrospinal fluid collections, as measured by number of vertebral segments, were associated with greater reduction of ventricular cerebrospinal fluid volume (Pearson’s r = -0.32, p = 0.036).
Conclusion: The current study found the brain tissue volume and ventricular cerebrospinal fluid are decreased in spontaneous intracranial hypotension patients. The change in ventricular cerebrospinal fluid volume, but not brain tissue volume change, was associated with the severity of spinal cerebrospinal fluid leakage. These results challenge the assumption that brain tissue volume is a fixed constant.
PMID: 32847387
DOI: 10.1177/0333102420950385

Piechowiak EI, Pospieszny K, Haeni L, Jesse CM, Peschi G, Mosimann PJ, Kaesmacher J, Mordasini P, Raabe A, Ulrich CT, Beck J, Gralla J, Dobrocky T.
Clin Neuroradiol. 2020 Aug 26. doi: 10.1007/s00062-020-00943-w. Online ahead of print.
Abstract
Background: Spinal imaging is essential to identify and localize cerebrospinal fluid (CSF) leaks in spontaneous intracranial hypotension (SIH) patients when targeted treatment is necessary.
Purpose: Provide an in-depth presentation of the conventional dynamic myelography (CDM) technique for localizing spinal CSF leaks in SIH patients.
Material and methods: Consecutive SIH patients with a CSF leak confirmed on CDM and postmyelography computed tomography (CT) investigated at our institution between 2013 and 2019 were retrospectively analyzed. Intraoperative reports were reviewed to confirm the accuracy of CDM.
Results: In total, 62 patients (mean age 45 years) were included; 48 with a ventral dural tear, 12 with a meningeal diverticulum, and in 2 patients positive for spinal longitudinal extradural CSF collection the site remained unclear. The leak was identified during the first and the second CDM in 43 and 17 patients, respectively. The use of CDM correctly identified the site of the CSF leak in all but one patient undergoing surgical closure (45/46, 98%). The mean fluoroscopy time was 7.8 min (range 1.8-14.4 min) with a radiation dose for a single examination of 310 mGy (range 28-1237 mGy).
Conclusion: The CDM procedure has a high accuracy for spinal CSF leak localization including dural tears and spinal nerve diverticula. It is the technique with the highest temporal resolution, is robust to breathing artifacts, allows great flexibility regarding patient positioning, compares favorably to other dynamic examinations with respect to the radiation dose and does not require general anesthesia. For CSF venous fistulas, however, other dynamic examinations, such as digital subtraction myelography, seem more appropriate.
PMID: 32845353
DOI: 10.1007/s00062-020-00943-w
Full-text open access

Nicholson PJ, Guest WC, van Prooijen M, Farb RI.
Clin Neuroradiol. 2020 Aug 17. doi: 10.1007/s00062-020-00942-x. Online ahead of print.
Abstract
Purpose: Both CT myelogram (CTM) and digital-subtraction myelogram (DSM) can be used to evaluate patients for possible cerebrospinal fluid (CSF) leaks. DSM is a relatively new technique. No data exists on the radiation dose associated with this procedure, and how it compares with CTM.
Materials and methods: All patients who underwent DSM for spontaneous intracranial hypotension (SIH) refractory to blood patching from Dec 2016 – Sept 2019 were retrospectively assessed. DSM dose factors were then recorded (cumulative fluoroscopy time, total kerma area product (KAP, mGy.cm2), cumulative air kerma (mGy), as well as CTM dose factors (included CTDIvol (mGy) and dose-length product (DLP, mGy.cm). These indices were then used to calculate the effective dose for both procedures using standardized conversion factors.
Results: 61 DSMs were performed in 42 patients, 33 of which also underwent CTM. The median effective dose was 6.6 mSv per DSM study (range: 1.2 – 17.7). On a per-patient basis (i.e. those patients who underwent more than one DSM (as the initial one was negative), the median total effective dose was 13 mSv for their total DSM imaging (range: 2.6 -31.7). For the CTM, the median effective dose was 19.7 mSv (range: 3.2 – 82.4 mSv).
Conclusion: The radiation dose with DSM appears to be significantly lower than that of CTM (p = 0.0005), when looking at CTM doses both from our institution and in the published literature.
PMID: 32804244
DOI: 10.1007/s00062-020-00942-x

Urbach H, Fung C, Dovi-Akue P, Lützen N, Beck J.
Dtsch Arztebl Int. 2020 Jul 6;117(27-28):480-487. doi: 10.3238/arztebl.2020.0480.
Abstract
Background: Spontaneous intracranial hypotension (SIH) is an underdiagnosed disease. Its incidence is estimated at 5 per 100 000 persons per year.
Methods: This review is based on a selective literature search in PubMed covering the years 2000-2019, as well as on the authors’ personal experience.
Results: The diagnostic and therapeutic methods discussed here are supported by level 4 evidence. SIH is caused by spinal leakage of cerebrospinal fluid (CSF) out of ventral dural tears or nerve root diverticula, or, in 2-5% of cases, through a fistula leading directly into the periradicular veins (CSF-venous fistula). In half of all patients, no CSF leak is demonstrable. A low CSF opening pressure on lumbar puncture is present in only one-third of patients; imaging studies are thus needed to confirm and localize a spinal CSF leak. Half of all patients in whom myelographic computed tomography (CT) reveals contrast medium reaching the epidural space have ventral dural tears, which tend to be located at upper thoracic spinal levels. Epidural blood patches applied under fluoroscopic or CT guidance can seal the CSF leak in 30-70% of patients, but 90% of patients with ventral dural tears will need operative closure. Some patients who have no visible epidural contrast medium on CT presumably do not have SIH, while others do, in fact, have a CSF leak from a diverticulum or a CSF-venous fistula and will need to have the site of the leak demonstrated with the aid of further studies, such as dynamic (subtraction) myelography in the lateral decubitus position.
Conclusion: The management of patients with SIH calls for complementary imaging studies to demonstrate the causative spinal CSF leak. Often, successful treatment requires surgical closure of the leak. In view of the sparse evidence available to date, controlled studies should be performed.
PMID: 33050997
PMCID: PMC7575894
DOI: 10.3238/arztebl.2020.0480

McCann M, Kelly K, Sokol D, Hughes MA.
Br J Neurosurg. 2020 Jun 26:1-3. doi: 10.1080/02688697.2020.1784845. Online ahead of print.
Abstract
Spontaneous intracranial hypotension (SIH) has been classified as a triad of postural headache, low CSF opening pressure (below 60mmH₂0) and diffuse pachymeningeal gadolinium enhancement on MRI. SIH is due to a non-iatrogenic defect in the dura somewhere along the neuraxis (usually in the spine). The resultant leak depressurizes the system and undermines the buoyancy-providing quality of CSF. In many cases the site of leak is not identified. Epidural blood patch (EBP) is a well-established treatment of SIH but is not always effective. We retrospectively analysed thirty-one cases of SIH who required at least one EBP. They were managed over a fifteen-year period at a single institution. EBP resulted in a significant improvement in headache for 77% of patients. We report in more detail on a particularly challenging outlier where severe SIH resulted in coma. Serial epidural blood patches, burr hole evacuation of chronic subdural haematomata, and infusion of 0.9% NaCl via an intradural spinal catheter were all required to enable long-term recovery.
PMID: 32590913 
DOI: 10.1080/02688697.2020.1784845

Dobrocky T, Winklehner A, Breiding PS, Grunder L, Peschi G, Häni L, Mosimann PJ, Branca M, Kaesmacher J, Mordasini P, Raabe A, Ulrich CT, Beck J, Gralla J, Piechowiak EI
AJNR Am J Neuroradiol. 2020 Jul; 41(7) 1309-1315
Abstract
BACKGROUND AND PURPOSE: Spine MR imaging plays a pivotal role in the diagnostic work-up of spontaneous intracranial hypotension. The aim of this study was to compare the diagnostic accuracy of unenhanced spine MR imaging and intrathecal gadolinium-enhanced spine MR imaging for identification and localization of CSF leaks in patients with spontaneous intracranial hypotension.
MATERIALS AND METHODS: A retrospective study of patients with spontaneous intracranial hypotension examined from February 2013 to October 2017 was conducted. Their spine MR imaging was reviewed by 3 blinded readers for the presence of epidural CSF using 3 different sequences (T2WI, 3D T2WI fat-saturated, T1WI gadolinium). In patients with leaks, the presumed level of the leak was reported.
RESULTS: In total, 103 patients with spontaneous intracranial hypotension (63/103 [61%] women; mean age, 50 years) were evaluated. Seventy had a confirmed CSF leak (57/70 [81%] proved intraoperatively), and 33 showed no epidural CSF on multimodal imaging. Intrathecal gadolinium-enhanced spine MR imaging was nonsuperior to unenhanced spine MR imaging for the detection of epidural CSF (P = .24 and .97). All MR imaging sequences had a low accuracy for leak localization. In all patients, only 1 leakage point was present, albeit multiple suspicious lesions were reported in all sequences (mean, 5.0).
CONCLUSIONS: Intrathecal gadolinium-enhanced spine MR imaging does not improve the diagnostic accuracy for the detection of epidural CSF. Thus, it lacks a rationale to be included in the routine spontaneous intracranial hypotension work-up. Heavily T2-weighted images with fat saturation provide high accuracy for the detection of an epidural CSF collection. Low accuracy for leak localization is due to an extensive CSF collection spanning several vertebrae (false localizing sign), lack of temporal resolution, and a multiplicity of suspicious lesions, albeit only a single leakage site is present. Thus, dynamic examination is mandatory before targeted treatment is initiated.
PMID: 32554417
PMCID: PMC7357665 (available on 2021-07-01)
DOI: 10.3174/ajnr.A6592

Häni L, Fung C, Jesse CM, Ulrich CT, Miesbach T, Cipriani DR, Dobrocky T, Z’Graggen WJ, Raabe A, Piechowiak EI, Beck J
Neurology. 2020 Jul 21; 95(3) e247-e255
Abstract
OBJECTIVE: To assess the pathophysiologic changes in patients with spontaneous intracranial hypotension (SIH) based on measures of CSF dynamics, and on the duration of symptoms, in a retrospective case-controlled study.
METHODS: We included consecutive patients investigated for SIH at our department from January 2012 to February 2018. CSF leak was considered confirmed if extrathecal contrast spillage was seen on imaging (CT or MRI) after intrathecal contrast application, or dural breach was detected by direct intraoperative visualization. We divided patients with a confirmed CSF leak into 3 groups depending on the symptom duration, as follows: ≤10, 11-52, and >52 weeks. Clinical characteristics and measures of CSF fluid dynamics obtained by computerized lumbar infusion testing were analyzed over time and compared with a reference population.
RESULTS: Among the 137 patients included, 69 had a confirmed CSF leak. Whereas 93.1% with < 10 weeks of symptoms displayed typical orthostatic headache, only 62.5% with >10 weeks of symptoms did (p = 0.004). Analysis of infusion tests revealed differences between groups with different symptom duration for CSF outflow resistance (p < 0.001), lumbar baseline pressure (p = 0.013), lumbar plateau pressure (p < 0.001), baseline pressure amplitude (p = 0.021), plateau pressure amplitude (p = 0.001), pressure-volume index (p = 0.001), elastance (p < 0.001), and CSF production rate (p = 0.001). Compared to the reference population, only patients with acute symptoms showed a significantly altered CSF dynamics profile.
CONCLUSION: A CSF leak dramatically alters CSF dynamics acutely, but the pattern changes over time. There is an association between the clinical presentation and changes in CSF dynamics.
PMID: 32522800
DOI: 10.1212/WNL.0000000000009812

Amrhein TJ, Gray L, Malinzak MD, Kranz PG
AJNR Am J Neuroradiol. 2020 Jul 16
Abstract
Spinal CSF-venous fistulas are a cause of spontaneous intracranial hypotension that can be difficult to detect on imaging. We describe how the respiratory phase affects the visibility of CSF-venous fistulas during myelography.
PMID: 32675336
DOI: 10.3174/ajnr.A6663 

Bond KM, Benson JC, Cutsforth-Gregory JK, Kim DK, Diehn FE, Carr CM.
AJNR Am J Neuroradiol. 2020 Jul 9.  Online ahead of print.
Abstract
Spontaneous intracranial hypotension is a condition characterized by low CSF volume secondary to leakage through a dural defect with no identifiable cause. Patients classically present with orthostatic headaches, but this symptom is not specific to spontaneous intracranial hypotension, and initial misdiagnosis is common. The most prominent features of spontaneous intracranial hypotension on intracranial MR imaging include “brain sag” and diffuse pachymeningeal enhancement, but these characteristics can be seen in several other conditions. Understanding the clinical and imaging features of spontaneous intracranial hypotension and its mimickers will lead to more prompt and accurate diagnoses. Here we discuss conditions that mimic the radiologic and clinical presentation of spontaneous intracranial hypotension as well as other disorders that CSF leaks can imitate.
PMID:  32646948
DOI: 10.3174/ajnr.A6637

Kim BR, Lee JW, Lee E, Kang Y, Ahn JM, Kang HS
J Clin Neurosci. 2020 Jul; 77 110-115
Abstract
Heavily T2-weighted MR myelography (HT2W-MRM) is emerging as an alternative approach for detection and follow up of CSF leaks. We aimed to assess epidural blood patch (EBP) treatment outcome when using HT2W-MRM as the primary modality for detecting CSF leak and planning EBP placement in routine clinical practice. Since 2018, patients at our institute suspected of having CSF leak, routinely HT2W-MRM instead of CT myelography to determine presence of the leak and identify the EBP target site. Fifty-nine consecutive patients suspected of having a CSF leak underwent HT2W-MRM. After excluding patients with subdural hematoma and poor image quality, 26 (10 men, 16 women; mean age 44.92 ± 12.6 years) patients were included in this study. Patients received EBP on the basis of HT2W-MRM assessments and clinical assessment. Imaging findings and clinical outcome were evaluated. CSF leak was identified in 21 patients (80.8%, 21/26) based HT2W-MRM. Most cases were graded on a confidence scale as CSF leak definitely (n = 13) or probably (n = 3) present. Successful clinical EBP treatment was achieved in 14 of 17 patients (82.4%) after first targeted EBP, and patient symptoms significantly improved after treatment (numerical rating score 6.4 before EBP, 1.3 after EBP, P <  0.001). HT2W-MRM based EBP are the rational and effective choices for CSF leak treatment in routine clinical practice.
PMID: 32402615
DOI: 10.1016/j.jocn.2020.05.010

Chazen JL, Robbins MS, Strauss SB, Schweitzer AD, Greenfield JP
AJNR Am J Neuroradiol 2020 May;41(5):938-940. Epub 2020 Apr 30.
Abstract
CSF-venous fistula is an important treatable cause of spontaneous intracranial hypotension that is often difficult to detect using traditional imaging techniques. Herein, we describe the technical aspects and diagnostic performance of MR myelography when used for identifying CSF-venous fistulas. We report 3 cases in which the CSF-venous fistula was occult on CT myelography but readily detected using MR myelography.
PMID:  32354709
PMCID: PMC7228166 (available on 2021-05-01) 
DOI: 10.3174/ajnr.A6521

Martineau P, Chakraborty S, Faiz K, Shankar J
Can Assoc Radiol J. 2020 May; 71(2) 174-185
Abstract
Spontaneous intracranial hypotension (SIH) is a significant cause of chronic, postural headaches. Spontaneous intracranial hypotension is generally believed to be associated with cerebrospinal fluid (CSF) leaks, and these leaks can be posttraumatic, iatrogenic, or idiopathic in origin. An integral part of the management of patients with this condition consists of localizing and stopping the leaks. Radiologists play a central role in the workup of this condition detecting leaks using computed tomography, magnetic resonance imaging, or nuclear imaging. In this article, we briefly review SIH and the various imaging modalities, which can be used to identify and localize a spontaneous CSF leak.
PMID: 32063004
DOI: 10.1177/0846537119888395

Madhavan AA, Kim DK, Carr CM, Luetmer PH, Covington TN, Cutsforth-Gregory JK, Brinjikji W
World Neurosurg. 2020 Apr 02; 138 398-403
Abstract
BACKGROUND: Klippel-Trenaunay syndrome (KTS) is associated with a wide variety of vascular and neurologic abnormalities, including venolymphatic malformations. A recent report postulated that patients with KTS may also be predisposed to spontaneous intracranial hypotension. We reviewed brain magnetic resonance imaging from 67 patients with KTS and unexpectedly noted findings of cerebrospinal fluid (CSF) hypotension in 4 of them.
CASE DESCRIPTION: Patients included a 39-year-old woman with episodic orthostatic headaches, a 62-year-old woman with orthostatic headaches and light-headedness, a 14-year-old girl with a history of headaches for years, and an asymptomatic 20-year-old man. All 4 patients had known KTS, and all had brain magnetic resonance imaging done during their evaluation showing evidence of CSF hypotension. The first 2 patients also had spine imaging demonstrating paraspinal and/or epidural venolymphatic malformations. The second patient had a meningeal diverticulum and underwent surgical repair with intraoperative evidence of a CSF leak.
CONCLUSIONS: Patients with KTS have an increased incidence of CSF hypotension. While it is possible that intrinsic dural weakness may be responsible for this association, we hypothesize that these patients are also predisposed to developing CSF venous fistulas. Paraspinal and epidural venolymphatic malformations have been described in multiple patients with CSF venous fistulas. Such malformations were present in 2 of our 4 patients who underwent spine imaging. Patients with KTS with orthostatic headaches may benefit from brain and spine magnetic resonance imaging to assess for evidence of CSF hypotension and venolymphatic malformations. Decubitus digital subtraction myelography may also have a role in these patients if CSF venous fistulas are suspected.
PMID: 32247792
DOI: 10.1016/j.wneu.2020.03.148 

Mamlouk MD, Shen PY, Jun P, Kanter JR, Ochi RP, Sedrak MF
Curr Probl Diagn Radiol. 2020 Apr 09
Abstract
OBJECTIVE: Spontaneous spinal cerebrospinal fluid (CSF) leaks are rare and challenging to diagnose and treat. Patients may present to a variety of physicians, and many patients are often referred to a specialized center with a dedicated spinal CSF leak program and expertise in this condition. To our knowledge, there are no reported publications on how to create such a program.
CONCLUSION: In this article, we describe the specific steps we took to develop a spinal CSF leak program, which we have implemented over a multihospital network.
PMID: 32305133
DOI: 10.1067/j.cpradiol.2020.03.004

Ferrante E, Trimboli M, Rubino F
Acta Neurol Belg. 2020 Feb; 120(1) 9-18
Abstract
Spontaneous intracranial hypotension (SIH) results from spinal cerebrospinal fluid (CSF) leaking. An underlying connective tissue disorder that predisposes to weakness of the dura is implicated in spontaneous spinal CSF leaks. During the last decades, a much larger number of spontaneous cases are identified and a far broader clinical SIH spectrum is recognized. Orthostatic headache is the main presentation symptom of SIH; some patients also have other manifestations, mainly cochlear-vestibular signs and symptoms. Differential diagnosis with other syndromes presenting with orthostatic headache is crucial. Brain CT, brain MR, spine MRI, and MRI myelography are the imaging modalities of first choice for SIH diagnosis. Invasive imaging techniques, such as myelography, CT myelography, and radioisotopic cisternography, are progressively being abandoned. No randomized clinical trials have assessed the treatment of SIH. In a minority of cases, SIH resolved spontaneously or with only conservative treatment. If orthostatic headache persists after conservative treatment, a lumbar epidural blood patch (EBP) without previous leak identification (so-called “blind” EBP) is a widely used initial intervention and may be repeated several times. If EBPs fail, after the CSF leak sites identification using invasive imaging techniques, other therapeutic approaches include: a targeted epidural patch, surgical reduction of dural sac volume, or direct surgical closure. The prognosis is generally good after intervention, but serious complications may occur. More research is needed to better understand SIH pathophysiology to refine imaging modalities and treatment approaches and to evaluate clinical outcomes.
PMID: 31215003
DOI: 10.1007/s13760-019-01166-8

Kim DK, Brinjikji W, Morris PP, et al.
AJNR Am J Neuroradiol. 2020 Jan;41(1):21-28. Epub 2019 Dec 19.
Abstract
Digital subtraction myelography is a valuable diagnostic technique to detect the exact location of CSF leaks in the spine to facilitate appropriate diagnosis and treatment of spontaneous spinal CSF leaks. Digital subtraction myelography is an excellent diagnostic tool for assessment of various types of CSF leaks, and lateral decubitus digital subtraction myelography is increasingly being used to diagnose CSF-venous fistulas. Lateral decubitus digital subtraction myelography differs from typical CT and fluoroscopy-guided myelograms in many ways, including equipment, supplies, and injection and image-acquisition techniques. Operators should be familiar with techniques, common pitfalls, and artifacts to improve diagnostic yield and prevent nondiagnostic examinations.
PMID:  31857327 
PMCID: PMC6975319 (available on 2021-01-01)
DOI: 10.3174/ajnr.A6368