MR cisternography: a new method for the diagnosis of CSF fistulae

Evaluation of signal intensity changes in dentate nucleus and globus pallidus on magnetic resonance imaging after intrathecal gadolinium-based contrast agent administration

PURPOSE

Gadolinium deposition has been reported in several normal anatomical structures in the brain after repeated administration of intravenous gadolinium-based contrast agents (GBCAs) used in magnetic resonance imaging (MRI). This study presents preliminary results to see if there is any gadolinium deposition in the dentate nucleus and globus pallidus after using intrathecal GBCAs.

METHODS

Between November 2018 and November 2020, 29 patients who underwent intrathecal contrast-enhanced MR cisternography with the suspicion of rhinorrhea were included in this prospective study. In contrast-enhanced MR cisternography, gadoterate meglumine was administered by intrathecal injection at a dose of 1 ml. One month later, patients had a control MRI with 3D T1 SPACE fat-saturated (FS) and susceptibility weighted images (SWI) sequences. The ratio of dentate nucleus signal intensity to middle cerebellar peduncle signal intensity (DN/MCP ratio) and the ratio of globus pallidus signal intensity to thalamus signal intensity (GP/T ratio) were calculated using region of interest (ROI) on pre-contrast and control MRI sequences.

RESULTS

There was no significant difference for DN/MCP ratio and GP/T ratio on 3D T1 SPACE FS and SWI sequences after intrathecal GBCAs administration compared to baseline MRI.

CONCLUSION

Administration of intrathecal GBCAs did not cause a measurable change in the signal intensity of the dentate nucleus and globus pallidus after a single injection.

Efficacy of Imaging Methods in the Detection and Diagnosis of Cerebrospinal Fluid Rhinorrhea

OBJECTIVE

To assess the diagnostic efficacy of various imaging methods in patients with suspected cerebrospinal fluid (CSF) rhinorrhea.

DATA SOURCES

The PubMed, EMBASE, SCOPUS, Web of Science, Cochrane Trials, and Google Scholar databases were searched up to December 2021.

REVIEW METHODS

Diagnostic accuracy was compared among seven radiological methods: computed tomography (CT), CT cisternography (CTC), magnetic resonance imaging (MRI), magnetic resonance cisternography (MRC), CT + MRI, radionuclide cisternography, and intrathecal gadolinium (Gd)-MRC. Sensitivity, specificity, and accuracy were used as outcomes of the analysis. Both a traditional pairwise meta-analysis and a network meta-analysis were performed.

RESULTS

Twenty-three trials were included in the analysis. The results of a network meta-analysis performed on a network consisting of seven diagnostic methods showed that all imaging modalities had greater diagnostic accuracy than CT, with the exception of CTC, which had lower sensitivity. Only intrathecal Gd-MRC was significantly superior to other imaging methods with regard to sensitivity and accuracy. Gd-MRC also showed the greatest surface under the cumulative ranking curve values for all of the outcomes (sensitivity: 0.9200; specificity: 0.8364; accuracy: 0.8920).

CONCLUSION

This network meta-analysis demonstrates that intrathecal Gd-MRC is the most useful diagnostic method to detect CSF rhinorrhea. Laryngoscope, 2022.

Quantifying cerebrospinal fluid dynamics: A review of human neuroimaging contributions to CSF physiology and neurodegenerative disease

Cerebrospinal fluid (CSF), predominantly produced in the ventricles and circulating throughout the brain and spinal cord, is a key protective mechanism of the central nervous system (CNS). Physical cushioning, nutrient delivery, metabolic waste, including protein clearance, are key functions of the CSF in humans. CSF volume and flow dynamics regulate intracranial pressure and are fundamental to diagnosing disorders including normal pressure hydrocephalus, intracranial hypotension, CSF leaks, and possibly Alzheimer's disease (AD). The ability of CSF to clear normal and pathological proteins, such as amyloid-beta (Aβ), tau, alpha synuclein and others, implicates it production, circulation, and composition, in many neuropathologies. Several neuroimaging modalities have been developed to probe CSF fluid dynamics and better relate CSF volume and flow to anatomy and clinical conditions. Approaches include 2-photon microscopic techniques, MRI (tracer-based, gadolinium contrast, endogenous phase-contrast), and dynamic positron emission tomography (PET) using existing approved radiotracers. Here, we discuss CSF flow neuroimaging, from animal models to recent clinical-research advances, summarizing current endeavors to quantify and map CSF flow with implications towards pathophysiology, new biomarkers, and treatments of neurological diseases.

ACR Appropriateness Criteria® Sinonasal Disease: 2021 Update

This article presents guidelines for initial imaging utilization in patients presenting with sinonasal disease, including acute rhinosinusitis without and with suspected orbital and intracranial complications, chronic rhinosinusitis, suspected invasive fungal sinusitis, suspected sinonasal mass, and suspected cerebrospinal fluid leak. CT and MRI are the primary imaging modalities used to evaluate patients with sinonasal disease. Given its detailed depiction of bony anatomy, CT can accurately demonstrate the presence of sinonasal disease, bony erosions, and anatomic variants, and is essential for surgical planning. Given its superior soft tissue contrast, MRI can accurately identify clinically suspected intracranial and intraorbital complications, delineate soft tissue extension of tumor and distinguish mass from obstructed secretions.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Usefulness of imaging studies for diagnosing and localizing cerebrospinal fluid rhinorrhea: A systematic review and meta-analysis

OBJECTIVES

To evaluate the usefulness of diagnosis by imaging studies for the localization of cerebrospinal fluid rhinorrhea.

METHODS

PubMed, SCOPUS, Embase, Web of Science, and Cochrane library databases were searched up to July 2021. True and false positive and negative data were collected along with the characteristics of each study. Methodological quality was assessed using the QADAS-2 tool.

RESULTS

Sixteen studies involving 472 patients were included. The diagnostic odds ratio of imaging studies was 13.6195 (95% confidence interval [7.4756; 24.8129]; I² = 28.1%). The area under the summary receiver operating characteristic curve was 0.712. Sensitivity, specificity, negative predictive value, and positive predictive value were 0.8507 ([0.7773; 0.9029]; 72.1%), 0.7827 ([0.6865; 0.8556], 26.8%), 0.5828 ([0.4398; 0.7132]; 67.4%), and 0.9407 ([0.8935; 0.9678]; 59.1%), respectively. In subgroup analysis, there were significant differences in sensitivity (computed tomography, 0.7421; computed tomography cisternography, 0.8872; magnetic resonance imaging, 0.8365; magnetic resonance cisternography, 0.8565; and intrathecal gadolinium magnetic resonance cisternography, 0.9307; radionuclide cisteronography, 0.7097; p  =  0.0481), and negative predictive value among imaging modalities (computed tomography, 0.3028; computed tomography cisternography, 0.4848; magnetic resonance imaging, 0.4658; magnetic resonance cisternography, 0.7465; and intrathecal gadolinium magnetic resonance cisternography, 0.8611, and radionuclide cisteronography, 0.5263; p  =  0.0046). There were no significant differences among imaging modalities in specificity, positive predictive value, or diagnostic odds ratio (p > 0.05).

CONCLUSION

Imaging studies can be used in the diagnosis of cerebrospinal fluid rhinorrhea. Gadolinium magnetic resonance cisternography showed the highest diagnostic accuracy. Also, magnetic resonance cisternography showed fair diagnostic accuracy without intrathecal injection. This article is protected by copyright. All rights reserved.

Diagnosis and Localization of Cerebrospinal Fluid Rhinorrhea: A Systematic Review

Background

Cerebrospinal fluid (CSF) rhinorrhea results from abnormal communications between the subarachnoid and sinonasal spaces. Accurate preoperative diagnosis and localization are vital for positive clinical outcomes. However, the diagnosis and localization of CSF rhinorrhea remain suboptimal due to a lack of accurate understanding of test characteristics.

Objective

This systematic review aims to assess the diagnostic accuracy of various tests and imaging modalities for diagnosing and localizing CSF rhinorrhea.

Methods

A systematic review of the MEDLINE and EMBASE databases was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results

Our search identified 4039 articles—53 cohort studies and 24 case series describing 1622 patients were included. The studies were heterogeneous and had a wide range of sensitivities and specificities. Many specificities were incalculable due to a lack of true negative and false positive results, thus precluding a meta-analysis. Median sensitivities and specificities were calculated for cohort studies of the following investigations: high-resolution computed tomography (HRCT) 0.93/0.50 (sensitivity/specificity), magnetic resonance cisternography (MRC) 0.94/0.77, computed tomography cisternography (CTC) 0.95/1.00, radionuclide cisternography (RNC) 0.90/0.50, and contrast-enhanced magnetic resonance cisternography (CEMRC) 0.99/1.00, endoscopy 0.58/1.00, topical intranasal fluorescein (TIF) 1.00/incalculable, intrathecal fluorescein (ITF) 0.96/1.00. Case series were reviewed separately. Etiology and site-specific data were also analyzed.

Conclusion

MR cisternography is more accurate than high-resolution CT at diagnosing and localizing CSF rhinorrhea. CT cisternography, contrast-enhanced MR cisternography, and radionuclide cisternography have good diagnostic characteristics but are invasive. Intrathecal fluorescein shows promising data but has not been widely adopted for purely diagnostic use. Office endoscopy has limited data but does not sufficiently diagnose CSF rhinorrhea independently. These findings confirm with current guidelines and evidence.

Endoscopic endonasal CSF rhinorrhea repair in children: Systematic review with meta-analysis

OBJECTIVES

Cerebrospinal fluid (CSF) rhinorrhea in children is relatively uncommon. Endoscopic repair techniques in adults have become first line for nasal-based CSF leaks, and this meta-analysis looks at the success rates of CSF leak cessation following endoscopic repair in children.

METHODS

Three researchers extracted information involving patient population, surgical technique, outcomes of interest, and study design. A computerized search of MEDLINE, EMBASE and the Cochrane library (January 1990-September 2019) looked for several papers on the subject of CSF leak repair in children using endoscopic technique.

RESULTS

A total of 15 studies met inclusion criteria. Endoscopic repair of CSF rhinorrhea in children shows a pooled weighted success rate of 94% after first attempt. The most common etiology was traumatic followed by congenital. Iatrogenic defects secondary to tumor resection are becoming more common. The high success rate was irrespective of the techniques using.

CONCLUSION

Endoscopic repair techniques have a highly successful closure rate for children presenting with CSF rhinorrhea.

Economic implications of localization strategies for cerebrospinal fluid rhinorrhea

BACKGROUND

The direct costs associated with different diagnostic algorithms to localize cerebrospinal fluid (CSF) rhinorrhea have not been described.

METHODS

A decision-tree analysis of imaging modalities used to localize CSF rhinorrhea was performed to compare associated direct costs. The primary outcome was cost, which was determined based on reimbursement data published by the Centers for Medicare and Medicaid Services in 2018. The model was parameterized after a literature review of published studies was performed from 1990 to 2018 to estimate the sensitivity CSF rhinorrhea localization of the following radiographic modalities: high-resolution computed tomography (HRCT), magnetic resonance cisternography (MRC), and CT cisternography (CTC). In addition to base case analysis, 1-way sensitivity analyses were also performed to evaluate the robustness of results to changes in model parameters.

RESULTS

Among patients with a high suspicion for CSF rhinorrhea, use of HRCT followed by exploration in the operating room if preliminary HRCT was negative was found to be the optimal localization modality from a cost perspective ($172.25). The next least costly algorithm was HRCT followed by MRC ($294.10). Imaging algorithms beginning with CTC were the next least costly modality ($727.37). Sensitivity analyses generally supported HRCT to be the optimal initial radiographic strategy over a wide range of parameter values.

CONCLUSION

This work advocates HRCT as first-line modality to localize CSF rhinorrhea from a cost perspective. Although algorithms beginning with MRC were on average $35 more expensive than those starting with CTC, associated risks of CTC were not modeled and may play a role in decision making.

[A modern approach to the diagnosis of nasal liquorrhea]

Nasal liquorrhea is cerebrospinal fluid leakage from cerebrospinal fluid spaces of the cerebral cavity into the nasal cavity or paranasal sinuses due to congenital or acquired abnormalities of the skull base bones and meninges of various etiologies. The severity of liquorrhea varies from hidden manifestations to profuse leakage of cerebrospinal fluid from the nasal cavity. The diagnosis of overt nasal liquorrhea is not problematic, but the diagnosis of latent liquorrhea is a challenge. In this case, the disease leads to potentially fatal complications, such as meningitis (the risk amounts to 10-37%), pneumocephaly, pneumonia, etc. These peculiarites give rise to two main tasks: early diagnosis confirming liquorrhea and accurate identification of the CSF fistula location when planning further surgical management.

PURPOSE

The study purpose was to review and comparatively analyze all modern methods of diagnosing nasal liquorrhea as well as to substantiate the most effective and promising approaches and algorithms.

MATERIAL AND METHODS

The study included papers in English and Russian found in the Pubmed database and related to the diagnosis of basal liquorrhea of different etiology and localization.

RESULTS

This review demonstrates that diagnostic tests vary widely in sensitivity, specificity, accuracy, invasiveness, and cost. Given all the criteria, detection of beta-2 transferrin or beta-trace protein is the best method for confirming nasal liquorrhea, and high-resolution computed tomography is the best technique for localization of the abnormality.

CONCLUSION

Based on the review, we suggest a diagnostic algorithm for nasal liquorrhea. However, the evidence presented in this review is unfortunately not very reliable, which indicates the existing need for more accurate studies.

Utility of Magnetic Resonance Imaging in Differentiating Cerebrospinal Fluid Leak from Middle Ear Effusion

Objective

To demonstrate the clinical utility, sensitivity, and specificity of standard magnetic resonance imaging (MRI) sequences in differentiating temporal bone cerebrospinal fluid leaks from all other middle ear effusions.

Study Design

Retrospective imaging review.

Setting

Academic medical center.

Subjects

Patients with cerebrospinal fluid leaks or other middle ear effusions who also underwent MRI.

Methods

Patients were assigned to cerebrospinal fluid leak and other effusion cohorts based on clinical course, findings at surgery/myringotomy, and beta-2 transferrin fluid analysis. Reviewers blinded to the clinical outcome examined T1-weighted, T2-weighted, diffusion-weighted, fluid-attenuated inversion recovery (FLAIR), and 3-dimensional (3D) acquired T2-weighted MRI sequences. For each sequence, fluid imaged in the temporal bone was graded as either similar or dissimilar in signal intensity to cerebrospinal fluid in the adjacent subarachnoid space. Signal similarity was interpreted as being diagnostic of a leak. Test characteristics in predicting the presence of a leak were calculated for each series.

Results

Eighty patients met criteria (41 leaks, 39 other effusions). The 3D T2 series was 76% sensitive and 100% specific in diagnosing a leak, and FLAIR was 44% sensitive and 100% specific. The T1-weighted (73% sensitive, 69% specific), T2-weighted (98% sensitive, 5.1% specific), and diffusion-weighted (63% sensitive, 66% specific) series were less useful.

Conclusions

MRI, with attention to 3D T2 and FLAIR series, is a noninvasive and highly specific test for diagnosing cerebrospinal fluid leak in the setting of an indeterminate middle ear effusion.

Detection of Cerebrospinal Fluid Leaks: Is There a Radiologic Standard of Care? A Systematic Review

INTRODUCTION

Diagnosis of cerebrospinal fluid (CSF) leaks traditionally involves laboratory testing of markers and appropriate imaging. Surgical localization can be difficult, and the inability to accurately localize skull base defects leads to increased rates of repair failure and complications. Many imaging techniques localizing and identifying CSF leaks have been proposed. Comparisons of current and investigational imaging techniques used to localize CSF leaks are reviewed.

METHODS

A comprehensive and systematic search through PubMed, Scopus, and reference lists from relevant articles was completed to identify literature on sensitivities of different imaging methods for localization and detection of CSF leaks. Prospective, retrospective, and case series published since 1995 that addressed imaging techniques for CSF leaks confined to the skull base were included. Sensitivities of each major imaging technique proposed were recorded and analyzed.

RESULTS

In total, 133 studies initially were screened from 2125 studies on preliminary search. Of these, 38 studies were included based on inclusion criteria. Studies were segregated by imaging modality. A total of 1000 patients with CSF leaks subsequently were evaluated.

CONCLUSIONS

Although radionuclide cisternography has been the historical standard, recent imaging techniques have emerged considering the low sensitivity. Computed tomography cisternography with contrast also has low sensitivity, even in active leaks. Although high-resolution computed tomography is commonly the initial study of choice, magnetic resonance imaging methods, particularly 3-dimensional imaging, may prove to be a more sensitive study of choice. Computed tomography/magnetic resonance imaging combination methods may show promise in localizing CSF leaks. Stratifying by status and etiology may be an important determinant. Further studies investigating various imaging techniques for localizing CSF leaks are needed.

Intrathecal gadolinium-enhanced MR cisternography in patients with otorhinorrhea: 10-year experience of a tertiary referral center

PURPOSE

Despite a considerable amount of literature that has been published about the use of intrathecal gadolinium-enhanced MR cisternography (IGE-MRC), there is still relatively lack of evidence as to its long-term effects. Our purpose in this study was twofold: firstly, to assess the long-term safety of the IGE-MRC; secondly, to evaluate the diagnostic performance of IGE-MRC for detecting cerebrospinal fluid (CSF) leak in otorhinorrhea patients.

METHODS

We retrospectively reviewed our imaging and clinical database for the patients admitted to our department for the evaluation of their otorhinorrhea between 2008 and 2017. Two radiologists evaluated the imaging studies independently. Consensus data was used in the analysis. Medical record review and phone call were used for the long-term follow-up.

RESULTS

The retrospective review yielded 166 patients. Rhinorrhea was present in 150 (90.4%) patients and otorrhea in 16 (9.6%) patients. Overall, 67 patients (40.5% of all patients) underwent operation for repair of the CSF leak site. Beta-transferrin test was available and positive in 57 (34.3%) patients. Overall sensitivity of IGE-MRC and paranasal high-resolution CT (HRCT) was 89.3 and 72%, respectively. Within the first 24 h after the procedure, none of the patients experienced a significant complication or adverse reaction. Ninety-nine patients (59.6%) had medical record and telephone follow-up. The mean follow-up duration with call was 37.1 months. Three (3%) patients complained about severe headache 3-4 weeks after the procedure.

CONCLUSIONS

IGE-MRC is a minimally invasive and highly sensitive imaging technique. No adverse side effect during our long-term follow-up might strengthen and support the safety of IGE-MRC.

Diagnosis of cerebrospinal fluid rhinorrhea: an evidence-based review with recommendations

BACKGROUND

Diagnostic strategies employed for cases of cerebrospinal fluid (CSF) rhinorrhea vary widely due to limited evidence-based guidance.

METHODS

A systematic review of the literature was performed using PubMed, EMBASE, and Cochrane databases from January 1990 through September 2014, to examine 9 diagnostic and localization modalities for CSF rhinorrhea. Benefit-harm assessments, value judgments and recommendations were made based on the available evidence. Study exclusion criteria were language other than English, pre-1990 studies, case reports, and nonrhinologic leak. All authors agreed on recommendations through an iterative process.

RESULTS

We reviewed 68 studies examining 9 practices pertinent to the diagnosis of CSF rhinorrhea, with a highest aggregate grade of evidence of C. The literature does not support the use of the ring sign, glucose testing, radionuclide cisternography (RNC), or computed tomography cisternography (CTC) for identification of CSF leak. Beta-2 transferrin is the most reliable confirmatory test for CSF leak. High-resolution CT (HRCT) is then recommended as the first-line study for localization. Magnetic resonance cisternography (MRC) should be used for CSF leak identification as a second line for each of these if beta-2 transferrin is not available or if HRCT is ambiguous. Intrathecal fluorescein (IF) may also be of benefit in certain clinical scenarios.

CONCLUSION

Despite relatively low levels of evidence, recommendations for the diagnosis and management of CSF rhinorrhea can be made based on the current literature. Higher-level studies are needed to better determine optimal diagnostic and clinical management approaches.

Use of the translabyrinthine approach to repair congenital spontaneous cerebrospinal fluid leakage in five Chinese patients with Mondini dysplasia

OBJECTIVES

To introduce a more effective surgical technique for the repair of spontaneous incurable cerebrospinal fluid (CSF) leakage (CSF otorrhea).

METHODS

The cases of five Chinese patients with Mondini dysplasia and CSF leakage were reviewed. All patients presented with rhinorrhea or otorrhea from childhood and recurrent meningitis attacks. CSF leakage was repaired surgically using the translabyrinthine approach.

RESULTS

Facial paralysis occurred in the first two patients, but was cured 2 months later. The other three patients recovered well and had no facial paralysis or complication. CSF leakage did not recur in any patient after follow-up periods of 0.5-3 years.

CONCLUSION

Mondini dysplasia with CSF leakage is rare. Adequate diagnosis and treatment are required to avoid life-threatening complications, such as meningitis. We recommend the translabyrinthine approach as an alternative surgical technique that reduces recurrence.

The diagnosis and surgical treatment of occult otogenic CSF leakage

CONCLUSIONS

The diagnosis of occult otogenic cerebrospinal fluid (CSF) leakage is challenging and it can easily be misdiagnosed. Some characteristics of clinical presentation can supply important clues and confirmed diagnosis should be obtained according to these clues and suitable imaging studies before meningitis develops. Different surgical techniques should be adopted to treat the CSF leakage according to different leakage etiologies, and good results can be obtained.

OBJECTIVE

The aim of the study was to evaluate the diagnosis and surgical treatment of occult otogenic CSF leakage, including the characteristics of clinical presentation, imaging studies, and operation methods in order to decrease the rate of misdiagnosis and obtain a good curative effect.

METHODS

We performed a retrospective review of 11 cases of CSF leakage that were all misdiagnosed and accompanied by meningitis, operated in our department from 2007 to 2012 after a mean follow-up of 3 years. In this context, the characteristics of clinical presentation, imaging studies, and management of CSF leakage were studied.

RESULTS

The CSF leakage had arisen traumatically (n = 9) or congenitally (n = 2). The medical history and special clinical presentation such as repeated otorrhea or rhinorrhea, fever, headache, and unilateral deafness can supply important diagnostic clues. Imaging studies including high-resolution noncontrast CT (HRCT), CT cisternography, and magnetic resonance imaging (MRI) are very important diagnostic methods. The surgical repairs were performed via a transmastoid approach (n = 8), packing the vestibule (n = 1) or a translabyrithine approach (n = 2). Recurrent leakage did not occur.

Intrathecal gadolinium-enhanced MR cisternography in the evaluation of CSF leakage

BACKGROUND AND PURPOSE

Radiologic identification of the location of the CSF leakage is important for proper surgical planning and increases the chance of dural repair. This article describes our experience in analyzing clinically suspected cranial CSF fistulas by using MR imaging combined with the intrathecal administration of a gadolinium-based contrast agent.

MATERIALS AND METHODS

A total of 85 consecutive patients with suspected CSF fistulas who presented with persistent or intermittent rhinorrhea or otorrhea lasting for more than 1 month between 2003 and 2007 were included in this study.

RESULTS

We observed objective CSF leakage in 64 of 85 patients (75%). The CSF leak was located in the ethmoidal region in 37 patients (58%), in the superior wall of the sphenoid sinus in 8 patients (13%), in the posterior wall of the frontal sinus in 10 patients (15%), in the superior wall of the mastoid air cells in 6 patients (9%), and from the skull base into the infratemporal fossa in 1 patient (2%). Two patients (3%) showed leakage into >1 paranasal sinus.

CONCLUSIONS

MR cisternography after the intrathecal administration of gadopentate dimeglumine represents an effective and minimally invasive method for evaluating suspected CSF fistulas along the skull base. It provides multiplanar capabilities without risk of radiation exposure and is an excellent approach to depict the anatomy of CSF spaces and CSF fistulas.

The contribution of 3D-CISS and contrast-enhanced MR cisternography in detecting cerebrospinal fluid leak in patients with rhinorrhoea

The aim of this prospective study was to evaluate the value of unenhanced (three-dimensional constructive interference in steady state (3D-CISS)) and contrast-enhanced MR cisternography (CE-MRC) in detecting the localisation of cerebrospinal fluid (CSF) leak in patients with rhinorrhoea. 17 patients with active or suspected CSF rhinorrhoea were included in the study. 3D-CISS sequences in coronal and sagittal planes and fat-suppressed T1-weighted spin-echo sequences in three planes before and after intrathecal contrast media administration were obtained. Images were obtained of the cribriform plate and sphenoid sinus. In addition, high-resolution CT (HRCT) was performed in order to evaluate the bony elements. The leak was present in 9/17 patients with 3D-CISS and 10/17 patients with CE-MRC. The leak from the cribriform plate to the nasal cavity in six patients and from the sphenoid sinus in four patients was nicely shown by CE-MRC. Eight of those patients were surgically treated, but spontaneous regression of the symptoms in two precluded any intervention. The leak localisations shown with CE-MRC were fully compatible with surgical results. The sensitivities of HRCT, 3D-CISS and CE-MRC for showing CSF leakage were 88%, 76% and 100%, respectively. In conclusion, 3D-CISS is a non-invasive and reliable technique, and should be the first-choice method to localise CSF leak. CE-MRC is helpful in conditions when there is no leak or in complicated cases with a positive beta2-transferrin measurement.

MR-Cisternography with T2-Weighted Single-Shot Fast Spin Echo Sequence in the Diagnosis of a Spontaneous CSF Fistula of the Sphenoid Sinus Causing Massive Pneumocephalus

A spontaneous CSF fistula of the sphenoid sinus was preoperatively diagnosed in a young woman presenting with massive pneumocephalus and rhinorrhea. Diagnosis was established by MR cisternography using a heavily T2-weighted 3D single-shot FSE sequence with half-Fourier analysis (3D-EXPRESS(®)), originally developed for imaging the inner ear. While unenhanced CT failed to detect the site of the fistula, MR permitted complete evaluation of the sellar/sphenoid region and tracked the CSF signal down to the nasal cavity.

Extraordinarily long-term posttraumatic cerebrospinal fluid fistula

Most posttraumatic cerebrospinal fluid (CSF) leakage is noticed by the patients with the first symptom, rhinorrhea. A 38-year-old woman presented with frequent clear continuous rhinorrhea and otorrhea for 5 years after basilar skull fracture. After this, meningitis was developed with subsequent CSF fistula. Her clinical symptom was improved by medical treatment. The dural defect and CSF leakage were not detected by computerized tomography (CT) cisternography. We report a rare case of persistent posttraumatic CSF fistula that continued for five years.

Steady-state MR imaging sequences: physics, classification, and clinical applications

Steady-state sequences are a class of rapid magnetic resonance (MR) imaging techniques based on fast gradient-echo acquisitions in which both longitudinal magnetization (LM) and transverse magnetization (TM) are kept constant. Both LM and TM reach a nonzero steady state through the use of a repetition time that is shorter than the T2 relaxation time of tissue. When TM is maintained as multiple radiofrequency excitation pulses are applied, two types of signal are formed once steady state is reached: preexcitation signal (S-) from echo reformation; and postexcitation signal (S+), which consists of free induction decay. Depending on the signal sampled and used to form an image, steady-state sequences can be classified as (a) postexcitation refocused (only S+ is sampled), (b) preexcitation refocused (only S- is sampled), and (c) fully refocused (both S+ and S- are sampled) sequences. All tissues with a reasonably long T2 relaxation time will show additional signals due to various refocused echo paths. Steady-state sequences have revolutionized cardiac imaging and have become the standard for anatomic functional cardiac imaging and for the assessment of myocardial viability because of their good signal-to-noise ratio and contrast-to-noise ratio and increased speed of acquisition. They are also useful in abdominal and fetal imaging and hold promise for interventional MR imaging. Because steady-state sequences are now commonly used in MR imaging, radiologists will benefit from understanding the underlying physics, classification, and clinical applications of these sequences.

Localization of cerebrospinal fluid leaks by gadolinium-enhanced magnetic resonance cisternography: a 5-year single-center experience

OBJECTIVE

Intrathecal gadolinium (Gd)-enhanced magnetic resonance (MR) cisternography is a newly introduced imaging method. Two main objectives of this study were to investigate the sensitivity of Gd-enhanced MR cisternography for presurgical localization of cerebrospinal fluid (CSF) leaks in patients with CSF rhinorrhea and to study the potential long-term adverse effects of intrathecal Gd application.

METHODS

Fifty-one patients (19 women; mean age, 36.2 yr) with CSF rhinorrhea were included in the study. A total of 0.5 ml of Gd was injected into the lumbar subarachnoid space. T1-weighted MR cisternographic images were obtained to detect CSF leakage. The patient's neurological states and vital signs were recorded for the first 24 hours after the procedure. Neurological evaluations were repeated 1, 3, and 12 months after the procedure. The patients were followed for at least 3 years with annual neurological examinations.

RESULTS

Gd-enhanced MR cisternography demonstrated CSF leaks in 43 of the 51 patients. The sensitivity of Gd-enhanced MR cisternography for localization of CSF leaks was 84%. Forty-four patients underwent surgery to repair dural tears. Surgical findings confirmed the results of Gd-enhanced cisternography in 43 of the 44 patients who underwent surgery (98%). Eight patients with negative Gd-enhanced MR cisternography had no active rhinorrhea at the time of procedure, and seven of them did not need surgery. None of the patients developed an acute adverse reaction that could be attributed to the procedure. None of the patients developed any neurological symptoms or signs caused by intrathecal Gd injection during a mean follow-up period of 4.12 years.

CONCLUSION

Gd-enhanced MR cisternography is a sensitive and safe imaging method for detection of CSF leaks in patients with rhinorrhea.

Nontraumatic skull base defects with spontaneous CSF rhinorrhea and arachnoid herniation: imaging findings and correlation with endoscopic sinus surgery in 27 patients

BACKGROUND AND PURPOSE

Defects at the skull base leading to spontaneous CSF rhinorrhea are rare lesions. The purpose of our study was to correlate CT and MR findings regarding the location and content of CSF leaks in 27 patients with endoscopic sinus surgery observations.

MATERIALS AND METHODS

Imaging studies in 27 patients with intermittent CSF rhinorrhea (CT in every patient including 10 examinations with intrathecal contrast, plain CT in 2 patients, and MR in 15 patients) were analyzed and were retrospectively blinded to intraoperative findings.

RESULTS

CT depicted a small endoscopy-confirmed osseous defect in 3 different locations: 1) within the ethmoid in 15 instances (53.6% of defects) most commonly at the level of the anterior ethmoid artery (8/15); 2) adjacent to the inferolateral recess of the sphenoid sinus in 7 patients including one patient with bilateral lesions (8/28 defects, 28.6%); 3) within the midline sphenoid sinus in 5 of 28 instances (17.9%). Lateral sphenoid defects (3.5 +/- 0.80 mm) were larger than those in ethmoid (2.7 +/- 0.77 mm, P < or = 0.029) or midsphenoid location (2.4 +/- 0.65 mm, P < or = 0.026). With endoscopy proven arachnoid herniation in 24 instances as reference, MR was correct in 14 of 15 instances (93.3%), CT cisternography in 5 of 8 instances (62.5%). Plain CT in 1 patient was negative.

CONCLUSION

In patients with a history of spontaneous CSF rhinorrhea, CT was required to detect osseous defects at specific sites of predilection. MR enabled differentiating the contents of herniated tissue and allowed identification of arachnoid tissue as a previously hardly recognized imaging finding.

The effects of topical granulocyte-macrophage colony-stimulating factor on dural healing in rats after induced cerebrospinal fluid leakage

OBJECT

Dural defects must be repaired to protect the central nervous system from contamination. Although there are various experimental and commercial substances available for this purpose, the ultimate method of watertight dural closure has yet to be discovered. In this study, the authors investigate the effects of topically applied recombinant mouse granulocyte-macrophage colony-stimulating factor (GM-CSF) on dural healing in a rat model of dural injury and cerebrospinal fluid leakage.

METHODS

In this experimental model, a dural defect at the level of the L1-2 vertebrae was created in 32 Wistar rats. Sixteen animals were treated with locally applied recombinant mouse GM-CSF postoperatively, and 16 animals received normal saline. The effects of GM-CSF on dural healing, cerebrospinal fluid leakage, and wound healing were assessed 2 and 4 weeks postoperatively. Dural healing was evaluated histologically.

RESULTS

Dural healing was increased in rats treated with GM-CSF compared with rats in the control group. This difference was statistically significant (p < 0.05).

CONCLUSIONS

Cerebrospinal fluid leakage may impede healing of dural defects. Topically applied GM-CSF seems to aid in dural healing.

Intrathecal administration of gadopentetate dimeglumine for MR cisternography of nasoethmoidal CSF fistula

OBJECTIVE

Accurate diagnosis and localization of dural defects associated with CSF fistulas are difficult and often involve multiple imaging studies performed at the appropriate clinical moment. Our purpose was to assess the utility of intrathecal administration of gadopentetate dimeglumine for MR cisternography of patients with CSF fistula suspected clinically to arise from defects in the nasoethmoidal regions.

CONCLUSION

MR cisternography was useful for evaluating patients with rhinorrhea and suspected CSF fistula. It depicted the fistula site in most patients. No adverse effects were found in any patient.

Meningitis following basal skull fracture in two in-line skaters

INTRODUCTION

In-line skating has been reported to cause severe head injury. Basilar skull fracture (BSF) is associated with a high risk of complication.

CASE REPORT

We report two children who had bacterial meningitis following seemingly trivial in-line skating injuries. In both, anterior BSF was diagnosed retrospectively following occurrence of Streptococcus pneumoniae meningitis.

DISCUSSION

The clinical signs indicating BSF depend on the fracture location. Plain skull radiography and computed tomography (CT) are not sensitive enough to detect thin fractures in the anterior cranial fossa. We argue that high resolution multiple-plane CT and coronal T2-weighted magnetic resonance imaging are indicated to diagnose BSF.

MR imaging features of idiopathic thoracic spinal cord herniations using combined 3D-fiesta and 2D-PC cine techniques

Idiopathic thoracic spinal cord herniation (TISCH) is a rare cause of surgically treatable progressive myelopathy. The authors report 3 cases of TISCH diagnosed based on conventional T1- and T2-weighted Spin-Echo (SE) MR images in one case, and T1- and T2-weighted SE images combined with 3D-FIESTA (Fast Imaging Employing Steady state Acquisition) and 2D-Phase-Contrast Cine MR imaging in 2 cases. Conventional MRI findings usually provided the diagnosis. 3D-FIESTA images confirmed it, showing the herniated cord in the ventral epidural space. Moreover, in combination with 2D-Phase Contrast cine technique, it was a sensitive method to for the detection of associated pre- or postoperative cerebrospinal fluid spaces abnormalities.

MRI cisternography with gadolinium-containing contrast medium: its role, advantages and limitations in the investigation of rhinorrhoea

Our purpose was to evaluate the utility of intrathecal gadopentetate dimeglumine -enhanced magnetic resonance cisternography (GdMRC). We injected 0.5 ml contrast medium into the subarachnoid space via lumbar puncture in 20 patients with suspected cerebrospinal fluid (CSF) rhinorrhoea. MRC showed CSF leakage in 14 patients with rhinorrhoea at the time of the examination, into the ethmoid air cells in nine, the sphenoid sinus in three and the frontal sinus in two cases. In 12 of these the site leakage was confirmed during surgical repair of the fistula. No leakage was observed in four patients with intermittent rhinorrhoea, not present at the time of the examination. GdMRC showed leakage in two patients with negative CT cisternography. GdMRC may prove better than CT cisternography, especially with slow CSF flow. We also showed low-dose GdMRC to be a feasible and relative safe way of confirming the presence of and localising active CSF leaks prior to surgical repair.

Virtual Endoscopic Images by 3D FASE Cisternography for Neurovascular Compression

Three-dimensional fast asymmetric spin echo (3D FASE) cisternography provides high spatial resolution and excellent contrast as a water image acquisition technique. It is also useful for the evaluation of various anatomical regions. This study investigated the usefulness and limitations of virtual endoscopic images obtained by 3D FASE MR cisternography in the preoperative evaluation of patients with neurovascular compression. The study included 12 patients with neurovascular compression: 10 with hemifacial spasm and two with trigeminal neuralgia. The diagnosis was surgically confirmed in all patients. The virtual endoscopic images obtained were judged to be of acceptable quality for interpretation in all cases. The areas of compression identified in preoperative diagnosis with virtual endoscopic images showed good agreement with those observed from surgery, except in one case in which the common trunk of the anterior inferior cerebellar artery and posterior inferior cerebellar artery (AICA-PICA) bifurcated near the root exit zone of the facial nerve. The veins are displayed in some cases but not in others. The main advantage of generating virtual endoscopic images is that such images can be used for surgical simulation, allowing the neurosurgeon to perform surgical procedures with greater confidence.

New techniques in cerebral imaging

This article presents a review of the current techniques in Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) that enhance the usefulness of these tests for the diagnosis of cerebral disease. We were able to analyze concepts and definitions and give a comparative description for each test studied including Multidetector/Perfusion CT, Xenon CT, CT-Angiogram, MRI-Perfusion, MRI-Diffusion, MRI-Spectroscopy, MRI CSF Flow, Functional MRI studies and Cerebral Angiography.

Intrathecal gadolinium-enhanced MR cisternography in the evaluation of clinically suspected cerebrospinal fluid rhinorrhea in humans: early experience

In this prospective multicenter study, the authors evaluated the utility of magnetic resonance (MR) cisternography after intrathecal administration of gadopentetate dimeglumine in 15 patients clinically suspected of having cerebrospinal fluid (CSF) rhinorrhea. By means of lumbar puncture, a single dose of 0.5 mL of gadopentetate dimeglumine was injected into the lumbar subarachnoid space. Thirteen patients showed leakage of contrast material through the cribriform plate into the ethmoid or sphenoid air cells. No leakage was observed in two patients. The study results show the relative safety and feasibility of low-dose gadolinium-enhanced MR cisternography in confirming the presence and determining the focus of active CSF leaks.

[Head and brain injuries. Place of imaging]

This article considers the various mechanisms of brain injury and specifies the most efficient radiologic technique for assessing patients, depending on clinical presentation. The brain injuries include either extracerebral and intracerebral lesions. The former require rapid diagnosis and therapy and the latter determine management in an intensive therapy, unit and outcome. Standard X-rays are obsolete. The CT, rapidly performed, is the most relevant imaging procedure for surgical lesions. Cortical contusions and diffuse axonal injuries are underestimated by CT and best depicted by MRI. Only late MRI has a strong correlation with neuropsychological outcome. In terms of prognosis, MRI needs to be evaluated. The indications include: a) unstable neurological status: CT; b) moderate head injury: CT may help to decide hospital admission; c) severe head injury: initial CT may be followed by MRI; d) long-term consequences: MRI. Special Indications: a) angio-MRI: suspicion of vascular lesion; b) CT with thin slices and bone window: depressed skull fracture; c) teleradiology (image transfer): to decide a patient transport from a peripheral hospital to a neurosurgical centre. In conclusion, CT remains the first-line examination to detect immediately life-threatening lesions. MRI is the examination of choice for full assessment of brain lesions.

Evaluation of intrathecal gadolinium-enhanced MR cisternography in a rabbit model of traumatic nasoethmoidal CSF fistula

This pilot study details the feasibility of intrathecal gadopentetate dimeglumine (Gd) administration in the detection of posttraumatic cerebrospinal fluid (CSF) fistula in an animal model. Five rabbits were used in this study. An attempt was made to create a traumatic CSF fistula surgically via a nasal approach. Seven days following the procedure, images of the cranium in sagittal and coronal planes were obtained utilizing a 1.9 T magnetic resonance (MR) imaging scanner before and after intrathecal injection of 16 pmol Gd. Following the imaging study, the animals were euthanized and grossly sectioned coronally to search for fistula formation. One animal died on the third day following the surgical procedure. The other four rabbits underwent the MR and gross pathologic study. Diagnosis of the fistula by intrathecal Gd-enhanced MR imaging was successful in two rabbits; this finding was confirmed by gross pathologic examination. No fistula was detected on either intrathecal Gd-enhanced MR imaging or on pathologic study in the remaining two rabbits. Intrathecal enhanced MR cisternography is a potentially promising technique for the evaluation of posttraumatic CSF fistulae.