Detection of cerebrospinal fluid leakage: initial experience with three-dimensional fast spin-echo magnetic resonance myelography

Comparing 2-dimensional versus 3-dimensional MR myelography for cerebrospinal fluid leak detection

Purpose

We compared cerebrospinal fluid (CSF) leak conspicuity and image quality as visualized using 3D versus 2D magnetic resonance (MR) myelography in patients with spinal CSF leaks.

Methods

Eighteen patients underwent spinal MR imaging at 3 Tesla. Three board-certified radiologists independently evaluated CSF leak conspicuity and image quality on a 4-point scale; the latter assessed by scoring fat suppression, venous visualization, and severity of CSF flow artifacts. Additionally, the evaluators ranked the overall performances of 2D versus 3D MR myelography upon completing side-by-side comparisons of CSF leak conspicuity. Inter-reader agreement was determined using the Gwet's AC1.

Results

The quality of 3D MR myelography images was significantly better than that of 2D MR myelography with respect to CSF leak conspicuity (mean scores: 3.3 vs. 1.9, p < 0.0001) and severity of CSF flow artifacts on the axial view (mean scores: 1.0 vs. 2.5, p = 0.0001). Inter-reader agreement was moderate to almost perfect for 2D MR myelography (AC1 = 0.55-1.00), and almost perfect for 3D MR myelography (AC1 = 0.85-1.00). Moreover, 3D MR myelography was judged to be superior to 2D acquisition in 78 %, 83 %, and 83 % of the samples per readers 1, 2 and 3, respectively; the inter-reader agreement was almost perfect (AC1: reader 1 vs. 2; 0.98, reader 2 vs. 3; 0.96, reader 3 vs. 1; 0.98).

Conclusion

CSF leaks are more conspicuous when using 3D MR myelography than when using its 2D counterpart; therefore, the former is more reliable for identifying such leaks.

Detection rate of MR myelography without intrathecal gadolinium in patients with newly diagnosed spontaneous intracranial hypotension

AIM

To evaluate the detection rate of magnetic resonance (MR) myelography without intrathecal gadolinium for cerebrospinal fluid (CSF) leakage in patients with newly diagnosed spontaneous intracranial hypotension (SIH) and to validate a published scoring system for predicting CSF leakage.

MATERIALS AND METHODS

This retrospective, observational, single-institution study included patients with newly diagnosed SIH between March 2015 and April 2021. Patients were included if they (a) had newly diagnosed SIH and (b) underwent initial brain MR imaging and preprocedural MR myelography with two- and three-dimensional turbo spin-echo sequences. Patients who underwent spine surgery or procedures including epidural injection and acupuncture were excluded. The detection rate was defined as the proportion of patients with a true-positive MR myelography result among all patients with confirmed CSF leakage. The interobserver agreement for the MR myelography results between two radiologists was analysed using weighted kappa statistics.

RESULTS

A total of 136 patients (mean age, 48 years; 70 women) with suspected SIH were included. Of these patients, 120 (88%, 120/136) were confirmed to have CSF leakage. Of the patients with confirmed CSF leakage, 90 (75%, 90/120) had epidural fluid collection. The detection rate of MR myelography for CSF leakage was 88% (105/120). The interobserver agreement between the two readers for detecting CSF leakage (κ = 0.76) or epidural fluid collection (κ = 0.76) on MR myelography was high. Among 24 patients with normal brain MR imaging results, 16 had CSF leakage (67%, 16/24).

CONCLUSIONS

Non-invasive MR myelography without intrathecal gadolinium should be considered to detect CSF leakage in patients with suspected SIH.

Diagnostic yield of MR myelography in patients with newly diagnosed spontaneous intracranial hypotension: a systematic review and meta-analysis

OBJECTIVES

To investigate the pooled diagnostic yield of MR myelography in patients with newly diagnosed spontaneous intracranial hypotension (SIH).

METHODS

A literature search of the MEDLINE/PubMed and Embase databases was conducted until July 25, 2021, including studies with the following inclusion criteria: (a) population: patients with newly diagnosed SIH; (b) diagnostic modality: MR myelography or MR myelography with intrathecal gadolinium for evaluation of CSF leakage; (c) outcomes: diagnostic yield of MR myelography or MR myelography with intrathecal gadolinium. The risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. DerSimonian-Laird random-effects modeling was used to calculate the pooled estimates. Subgroup analysis regarding epidural fluid collection and meta-regression were additionally performed.

RESULTS

Fifteen studies with 643 patients were included. Eight studies used MR myelography with intrathecal gadolinium, and 11 used MR myelography. The overall quality of the included studies was moderate. The pooled diagnostic yield of MR myelography was 86% (95% CI, 80-91%) and that of MR myelography with intrathecal gadolinium was 83% (95% CI, 51-96%). There was no significant difference in pooled diagnostic yield between MR myelography and MR myelography with intrathecal gadolinium (p = 0.512). In subgroup analysis, the pooled diagnostic yield of the epidural fluid collection was 91% (95% CI, 84-94%). In meta-regression, the diagnostic yield was unaffected regardless of consecutive enrollment, magnet strength, or 2D/3D.

CONCLUSIONS

MR myelography had a high diagnostic yield in patients with SIH. MR myelography is non-invasive and not inferior to MR myelography with intrathecal gadolinium.

KEY POINTS

• The pooled diagnostic yield of MR myelography was 86% (95% CI, 80-91%) in patients with spontaneous intracranial hypotension. • There was no significant difference in pooled diagnostic yield between MR myelography and MR myelography with intrathecal gadolinium. • MR myelography is non-invasive and not inferior to MR myelography with intrathecal gadolinium.

Intravenous enhanced 3D FLAIR imaging to identify CSF leaks in spontaneous intracranial hypotension: Comparison with MR myelography

Purpose

To evaluate the clinical utility of intravenous gadolinium-enhanced heavily T2-weighted 3D fluid-attenuated inversion recovery (HT2-FLAIR) imaging for identifying spinal cerebrospinal fluid (CSF) leaks in patients with spontaneous intracranial hypotension (SIH).

Methods

Patients with SIH underwent MR myelography and post-contrast HT2-FLAIR imaging after an intravenous gadolinium injection. Two types of CSF leaks (epidural fluid collection and CSF leaks around the nerve root sleeve) at each vertebral level were compared between the 2 sequences. The total numbers of CSF leaks and vertebral levels involved were recorded for the whole spine. The sequence that was superior for the overall visualization of epidural and paraspinal fluid collection was then selected.

Results

Nine patients with SIH were included in the present study. HT2-FLAIR imaging was equivalent or superior to MR myelography at each level for detecting the 2 types of CSF leaks. In the 2 types of CSF leaks, the total numbers of CSF leaks and levels involved were higher on HT2-FLAIR images than on MR myelography, while no significant difference was observed for CSF leaks around the nerve root sleeve. In all 9 patients, HT2-FLAIR imaging was superior to MR myelography for the overall visualization of epidural and paraspinal fluid collection.

Conclusion

Intravenous gadolinium-enhanced HT2-FLAIR imaging was superior to MR myelography for the visualization of CSF leaks in patients with SIH. This method can be useful for identifying spinal CSF leaks.

Spine MRI in Spontaneous Intracranial Hypotension for CSF Leak Detection: Nonsuperiority of Intrathecal Gadolinium to Heavily T2-Weighted Fat-Saturated Sequences

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.

A blast from the past!: The value of adding single slice magnetic resonance myelography sequence to magnetic resonance imaging of the spine; a flashback to the conventional myelography of the past

Background:

The study was undertaken to determine whether a single slice magnetic resonance (MR) myelogram sequence improves the interpretation and diagnostic yield for magnetic resonance imaging (MRI) of the spine.

Methods:

A total of 100 cases with positive findings were retrospectively reviewed. All patients had initial imaging with sagittal T1-weighted (T1-W) and T2-weighted (T2-W) scans, followed by axial T2-W images. Subsequently, a heavily T2-W single slice MR myelogram sequence was acquired in coronal and sagittal planes. The MR myelogram images were evaluated initially by a radiologist, and, further independently reviewed, by a neurologist, neurosurgeon, and spine surgeon. The utility of the MR myelogram in establishing the diagnosis was graded on a 4-point scale.

Results:

Out of 100 cases, 53% showed degenerative spine or disc disease, 14% space occupying lesions, 13%, congenital lesions, 7% infection, and 7% other conditions. The MR myelogram contributed additional information in 50-74% cases. The intraclass correlation coefficient showed overall good agreement between observers in grading the utility of MR myelogram.

Conclusion:

Single slice MR myelography is noninvasive avoiding the complications associated with lumbar punctures/intrathecal contrast injections, while image acquisition takes only an added 6-8 s. Although MR myelogram has no value as a stand-alone sequence, its inherent advantage is that it completes the overview of the spinal pathology in entirety, and adds vital three-dimensional information in 50-74% of cases.

Spontaneous Intracranial Hypotension: Recommendations for Management

A literature search found no clinical trials or guidelines addressing the management of spontaneous intracranial hypotension (SIH). Based on the available literature and expert opinion, we have developed recommendations for the diagnosis and management of SIH. For typical cases, we recommend brain magnetic resonance (MR) imaging with gadolinium to confirm the diagnosis, and conservative measures for up to two weeks. If the patient remains symptomatic, up to three non-directed lumbar epidural blood patches (EBPs) should be considered. If these are unsuccessful, non-invasive MR myelography, radionuclide cisternography, MR myelography with intrathecal gadolinium, or computed tomography with myelography should be used to localize the leak. If the leak is localized, directed EPBs should be considered, followed by fibrin sealant or neurosurgery if necessary. Clinically atypical cases with normal brain MR imaging should be investigated to localize the leak. Directed EBPs can be used if the leak is localized; non-directed EBPs should be used only if there are indirect signs of SIH.

Lumbar puncture-related cerebrospinal fluid leakage on magnetic resonance myelography: is it a clinically significant finding?

Background

Post-dural puncture headache (PDPH) due to excessive cerebrospinal fluid (CSF) leakage is a well-known complication of lumbar puncture. Although various factors, especially the type of spinal needle, have been demonstrated to be associated with PDPH, the clinical implications of CSF leakage detected on magnetic resonance myelography (MRM) images remain unclear. The objective of this case–control study was to evaluate the association between radiologically visualized CSF leakage and PDPH.

Methods

Clinical data including patients’ age and gender, types of spinal needle, duration of bed rest, interval between lumbar puncture procedures and MRM studies, and incidence of PDPH were compared between patients who were radiologically-positive and -negative for CSF leakage.

Results

Of the 22 patients with definite CSF leakage on MRM images, most were asymptomatic (86%, 19/22). The remaining three patients, who were suffering from PDPH, only complained of headaches and were treated conservatively. In a review of patients’ clinical data, there were no significant differences in any parameter including the incidence of PDPH between the 22 patients who were radiologically-positive for CSF leakage and the 31 radiologically-negative patients.

Conclusion

The significance of radiologically visualized CSF leakage should not be overestimated, as most such incidents are not associated with PDPH and do not require any treatment.

A review article on the diagnosis and treatment of cerebrospinal fluid fistulas and dural tears occurring during spinal surgery

Background:

In spinal surgery, cerebrospinal fluid (CSF) fistulas attributed to deliberate dural opening (e.g., for tumors, shunts, marsupialization of cysts) or inadvertent/traumatic dural tears (DTs) need to be readily recognized, and appropriately treated.

Methods:

During spinal surgery, the dura may be deliberately opened to resect intradural lesions/tumors, to perform shunts, or to open/marsupialize cysts. DTs, however, may inadvertently occur during primary, but are seen more frequently during revision spinal surgery often attributed to epidural scarring. Other etiologies of CSF fistulas/DTs include; epidural steroid injections, and resection of ossification of the posterior longitudinal ligament (OPLL) or ossification of the yellow ligament (OYL). Whatever the etiology of CSF fistulas or DTs, they must be diagnosed utilizing radioisotope cisternography (RIC), magnetic resonance imaging (MRI), computed axial tomography (CT) studies, and expeditiously repaired.

Results:

DTs should be repaired utilizing interrupted 7-0 Gore-Tex (W.L. Gore and Associates Inc., Elkton, MD, USA) sutures, as the suture itself is larger than the needle; the larger suture occludes the dural puncture site. Closure may also include muscle patch grafts, dural patches/substitutes (bovine pericardium), microfibrillar collagen (Duragen: Integra Life Sciences Holdings Corporation, Plainsboro, NJ), and fibrin glues or dural sealants (Tisseel: Baxter Healthcare Corporation, Deerfield, IL, USA). Only rarely are lumbar drains and wound-peritoneal and/or lumboperitoneal shunts warranted.

Conclusion:

DTs or CSF fistulas attributed to primary/secondary spinal surgery, trauma, epidural injections, OPLL, OYL, and other factors, require timely diagnosis (MRI/CT/Cisternography), and appropriate reconstruction.

Tips and traps in neurological imaging: imaging the perimedullary spaces

The spinal canal is frequently a source of difficulties, traps and diagnostic errors. Pitfalls related to artifacts are resolved by using appropriate sequences. Good knowledge of the appearance of certain particular anatomical structures (the cauda equina roots, the radicular veins of the lumbar spine and conus medullaris, the dorsal root ganglion) and of frequent variants (fibrolipoma of the filum terminale, common root sheaths, root cysts) will avoid a good many errors. Dilatation of epidural veins in intracranial hypotension can simulate the contrast enhancement of a tumour. An increase in epidural fat can induce pathogenic stenosis of the dural sheath.

Comparison of the radioisotope cisternography findings of spontaneous intracranial hypotension and iatrogenic cerebrospinal fluid leakage focusing on chronological changes

BACKGROUND

Radioisotope cisternography (RICG) is useful for detecting cerebrospinal fluid (CSF) leakage in spontaneous intracranial hypotension (SIH) patients. However, RICG can cause iatrogenic CSF leakage (ICSFL) due to a lumbar puncture.

OBJECTIVES

To compare the RICG findings of SIH and ICSFL.

METHODS

The presence of direct findings suggesting CSF leakage and indirect findings including early visualization of the bladder and absence of radioactivity over the brain convexities were evaluated in seven SIH and six ICSFL patients. Radioisotope clearance was assessed semi-quantitatively.

RESULTS

In contrast to the variety of anatomical levels at which direct findings were detected in the SIH patients, the ICSFL patients only displayed direct findings at the lumbosacral level. None of the ICSFL patients displayed direct findings at 1 hour after the tracer injection. Although early visualization of the bladder was depicted in all patients, no activity was visualized over the brain convexities in the SIH patients. In the semi-quantitative analysis, the tracer retention index at 24 hours was lower in the SIH patients than the ICSFL patients.

CONCLUSIONS

The early appearance of direct findings above the lumbosacral level, the absence of radioactivity over the brain convexities and a low tracer retention index are suggestive of SIH.

Spontaneous intracranial hypotension

Since the introduction of magnetic resonance imaging (MRI), spontaneous intracranial hypotension has been diagnosed much more frequently. The aim of this review is to discuss the symptoms and signs of the condition, in particular the characteristics of the associated headache, with sudden onset after sitting or standing, so that it can be included under the rubric of 'thunderclap headache'. This type of headache, like post lumbar puncture headaches, may be caused by cerebral vasodilatation and exacerbated by lowered pressure of the cerebrospinal fluid (CSF). Other symptoms include neck stiffness, nausea, vomiting, vertigo, tinnitus, deafness, and cognitive abnormalities. The clinical picture can sometimes mimic frontotemporal dementia, and the behaviour of some patients can sometimes be described as hypoactive-hypoalert, with somnolence, impaired attention, and stereotyped motor activity. Sagging of the brain, caused by leakeage of the CSF, can cause lesions in the brainstem with stupor, gaze palsies, and cranial nerve palsies. The condition can be a risk factor for cerebral venous thrombosis because of slowing of the blood flow and distortion of the blood vessels. The clinical picture may well suggest the diagnosis, but the headache may possibly indicate a subarachnoid haemorrhage. However, MRI will help to confirm the diagnosis and to localize the site of the CSF leak. MRI myelograms are of particular value, but if they are equivocal a computed tomography myelogram should be performed. The leakage of CSF is due to a tear in the dura, most frequently where the spinal roots leave the subarachnoid space. If this does not heal with bedrest, an epidural blood patch or a percutaneous injection of fibrin glue may be needed. More information is required on long-term follow-up.