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Purpose: Presented here is a strategy of sequential lateral decubitus digital subtraction myelography (LDDSM) followed closely by lateral decubitus CT (LDCT) to facilitate cerebrospinal fluid (CSF)-venous fistula (CVF) localization., Materials and Methods: This is a retrospective analysis of patients referred to our institution for evaluation of CSF leak. Patients with Type 1 and Type 2 leaks, and those not displaying MR brain stigmata of intracranial hypotension were excluded. All patients underwent consecutive LDDSM and LDCT. If the CVF was not localized on the first LDDSM-LDCT pair the patient returned for contralateral examinations. Images were reviewed for CVF and for accumulation of contrast within the renal pelvises expressed as a renal pelvis contrast score (RPCS) in Hounsfield units (HU)., Results: Twenty-two patients were included in this study. In 21 of 22 patients (95%) a CVF was identified yielding an RPCS for the LDDSM-LDCT pair ipsilateral to the CVF ranging from 71 to 423 with an average of 146 HU. An RPCS of the negative side LDDSM-LDCT pair contralateral to a CVF was available in 8 patients and averaged 51 HU. In 4 patients the initial bilateral LDDSM-LDCT pairs did not reveal the location of the CVF however in 3 of these 4 cases the CVF was revealed on a third LDDSM repeated ipsilateral to the higher RPCS., Conclusion: The strategy of sequential LDDSM-LDCT coupled with evaluation of renal accumulation of contrast agent appears to improve the rate of CVF localization and warrants further evaluation.

Purpose: Traditionally, in the work-up of patients for spontaneous intracranial hypotension, T1 post-contrast imaging is performed in order to assess for pachymeningeal enhancement. The aim of this study is to assess whether pachymeningeal hyperintensity can be identified on a non-contrast FLAIR sequence in these patients as a surrogate sign for pachymeningeal enhancement., Methods: The patient cohort was identified from a prospectively maintained database of patients with a clinical diagnosis of intracranial hypotension. Patients who had both a post-contrast T1 sequence brain as well as non-contrast FLAR sequence of the brain were reviewed. Imaging was retrospectively reviewed by three independent neuroradiologists. Each study was assessed for the presence or absence of pachymeningeal hyperintensity on the FLAIR sequence., Results: From January 2010 to July 2022, 177 patients were diagnosed with spontaneous intracranial hypotension. In total, 121 were excluded as post-contrast imaging was not performed during their work-up. Twenty-four were excluded as the FLAIR sequence was performed after administration of contrast. Six were excluded as there was no pachymeningeal thickening present on T1 post-contrast imaging, although there were other signs of intracranial hypotension. The study group therefore consisted of 26 patients. Pachymeningeal thickening was correctly identified on the non-contrast FLAIR sequence in all patients (100%)., Conclusion: Where present, diffuse pachymeningeal hyperintensity can be accurately identified on a non-contrast FLAIR sequence in patients with spontaneous intracranial hypotension. This potentially obviates the need for gadolinium base contrast agents in the work-up of these patients., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Cerebrospinal fluid-venous fistulas (CVFs) may cause cerebrospinal fluid leaks resulting in spontaneous intracranial hypotension (SIH). Surgical treatment of CVFs aims to eliminate abnormal fistulous connections between the subarachnoid space and the epidural venous plexus at the level of the nerve root sleeve. The authors propose a percutaneous minimally invasive technique for surgical ligation of CVF as an alternative to the traditional open approach using a tubular retractor system., Observations: Minimally invasive surgical (MIS) ligation of spinal CVF was performed in 5 patients for 6 CVFs. The definite disconnection of the CVF was achieved in all patients by clipping and additional silk tie ligation of the fistula. None of the patients experienced surgical complications or required transition to an open procedure. One patient underwent 2 MIS procedures for 2 separate CVFs. Postoperative clinical follow-up and cranial magnetic resonance imaging confirmed resolution of symptoms and radiographic SIH stigmata., Lessons: MIS ligation of CVFs is safe and efficient. It represents an elegant and less invasive procedure, reducing the risk of wound infections and time to recovery. However, preparedness for open ligation is warranted within the same surgical setting in cases of complications and difficult accessibility.

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., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

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., (© 2020 by American Journal of Neuroradiology.)

Objective: Spontaneous spinal CSF-venous fistulas are a distinct type of spinal CSF leak recently described in patients with spontaneous intracranial hypotension (SIH). Using digital subtraction myelography (DSM) with the patient in the prone position, the authors have been able to demonstrate such fistulas in about one-fifth of patients with SIH in whom conventional spinal imaging (MRI or CT myelography) showed no evidence for a CSF leak (i.e., the presence of extradural CSF). The authors compared findings of DSM with patients in the lateral decubitus position versus the prone position and now report a significantly increased yield of identifying spinal CSF-venous fistulas with this modification of their imaging protocol., Methods: The population consisted of 23 patients with SIH who underwent DSM in the lateral decubitus position and 26 patients with SIH who underwent DSM in the prone position. None of the patients had evidence of a CSF leak on conventional spinal imaging., Results: A CSF-venous fistula was demonstrated in 17 (74%) of the 23 patients who underwent DSM in the lateral decubitus position compared to 4 (15%) of the 26 patients who underwent DSM in the prone position (p < 0.0001). The mean age of these 16 women and 5 men was 52.5 years (range 36-66 years)., Conclusions: Among SIH patients in whom conventional spinal imaging showed no evidence of a CSF leak, DSM in the lateral decubitus position demonstrated a CSF-venous fistula in about three-fourths of patients compared to only 15% of patients when the DSM was performed in the prone position, an approximately five-fold increase in the detection rate. Spinal CSF-venous fistulas are not rare among patients with SIH.

Background and Purpose: Localization of the culprit CSF leak in patients with spontaneous intracranial hypotension can be difficult and is inconsistently achieved. We present a high yield systematic imaging strategy using brain and spine MRI combined with digital subtraction myelography for CSF leak localization., Materials and Methods: During a 2-year period, patients with spontaneous intracranial hypotension at our institution underwent MR imaging to determine the presence or absence of a spinal longitudinal extradural collection. Digital subtraction myelography was then performed in patients positive for spinal longitudinal extradural CSF collection primarily in the prone position and in patients negative for spinal longitudinal extradural CSF collection in the lateral decubitus positions., Results: Thirty-one consecutive patients with spontaneous intracranial hypotension were included. The site of CSF leakage was definitively located in 27 (87%). Of these, 21 were positive for spinal longitudinal extradural CSF collection and categorized as having a ventral (type 1, fifteen [48%]) or lateral dural tear (type 2; four [13%]). Ten patients were negative for spinal longitudinal extradural CSF collection and were categorized as having a CSF-venous fistula (type 3, seven [23%]) or distal nerve root sleeve leak (type 4, one [3%]). The locations of leakage of 2 patients positive for spinal longitudinal extradural CSF collection remain undefined due to resolution of spontaneous intracranial hypotension before repeat digital subtraction myelography. In 2 (7%) patients negative for spinal longitudinal extradural CSF collection, the site of leakage could not be localized. Nine of 21 (43%) patients positive for spinal longitudinal extradural CSF collection were treated successfully with an epidural blood patch, and 12 required an operation. Of the 10 patients negative for spinal longitudinal extradural CSF collection (8 localized), none were effectively treated with an epidural blood patch, and all have undergone ( n = 7) or are awaiting ( n = 1) an operation., Conclusions: Patients positive for spinal longitudinal extradural CSF collection are best positioned prone for digital subtraction myelography and may warrant additional attempts at a directed epidural blood patch. Patients negative for spinal longitudinal extradural CSF collection are best evaluated in the decubitus positions to reveal a CSF-venous fistula, common in this population. Patients with CSF-venous fistula may forgo further epidural blood patch treatment and go on to surgical repair., (© 2019 by American Journal of Neuroradiology.)

Background: Spontaneous intracranial hypotension (SIH) is a condition of low cerebrospinal fluid volume and pressure caused by a leak of cerebrospinal fluid through a dural defect. Diagnosis and management can be difficult, often requiring coordination between multiple disciplines for myelography, blood patching, and possible surgical repair. Patients should be monitored closely, because they can deteriorate into a coma or even death. There are no widely accepted guidelines for the management of SIH., Methods and Conclusions: We review the existing SIH literature, illustrate management challenges via a case review, and propose an algorithm developed by neurosurgeons, radiologists, and anesthesiologists intended to simplify and streamline the management of SIH., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to determine the accuracy and utility of contrast-enhanced MR angiography (CE-MRA) in spinal dural arteriovenous fistulas (SDAVF)., Methods: A retrospective analysis from 1999-2012 identified 70 patients clinically suspected of harboring a SDAVF. Each patient underwent consecutive conventional MR-imaging, CE-MRA, and digital subtraction angiography (DSA). The presence or absence of serpentine flow voids, T2-weighted hyperintensity, and cord enhancement were evaluated, as well as location of the fistula as predicted by CE-MRA. DSA was used as the reference standard., Results: Of the 70 cases, 53 were determined to be a SDAVF, 10 cases were shown to be other forms of vascular malformation, and 7 were DSA-negative. On MRI, all reported cases of SDAVF showed serpentine flow voids (100 %). T2-weighted hyperintensity was seen in 48 of 50 cases (96 %), extending to the conus in 41 of 48 cases (85 %). Cord enhancement was seen in 38 of 41 cases (93 %). CE-MRA correctly localized the SDAVF in 43 of the 53 cases (81 %)., Conclusions: CE-MRA is a useful non-invasive examination for the detection and localization of SDAVF. CE-MRA facilitates but does not replace DSA as confirmation of location, fistula type, and arterial detail, which are required before treatment., Key Points: • CE-MRA correctly localized the site of the SDAVF in over 80 % of cases. • CE-MRA facilitates diagnostic DSA and expedites the diagnostic process. • CE-MRA does not replace diagnostic DSA in SDAVF cases as confirmative test. • CE-MRA provides better understanding of missed or mislocalized SDAVF cases.

While ethambutol optic neuropathy usually causes central or cecocentral scotomas, bitemporal visual field defects also have been reported. The pathogenesis of the bitemporal hemianopia has not been established. This article describes magnetic resonance imaging abnormalities involving the optic chiasm in a patient with bitemporal visual field loss. To our knowledge, these neuroimaging findings have not been previously described in association with ethambutol therapy.

Background and Purpose: Prospective differentiation between reversible cerebral vasoconstriction syndrome and central nervous system vasculitis can be challenging. We hypothesized that high-resolution vessel wall MRI would demonstrate arterial wall enhancement in central nervous system vasculitis but not in reversible cerebral vasoconstriction syndrome., Methods: We identified all patients with multifocal segmental narrowing of large intracranial arteries who had high-resolution vessel wall MRI and follow-up angiography at our institute over a 4-year period and performed a detailed chart review., Results: Three patients lacked arterial wall enhancement, and these all had reversal of arterial narrowing within 3 months. Four patients demonstrated arterial wall enhancement, and these had persistent or progressive arterial narrowing at a median follow-up of 17 months (range, 6-36 months) with final diagnoses of central nervous system vasculitis (3) and cocaine vasculopathy (1)., Conclusions: Preliminary results suggest that high-resolution contrast-enhanced vessel wall MRI may enable differentiation between reversible cerebral vasoconstriction syndrome and central nervous system vasculitis.

Background and Purpose: CTA is becoming the frontline modality to reveal aneurysms in patients with SAH. However, in about 20% of SAH patients no aneurysm is found. In these cases, intra-arterial DSA is still performed. Our aim was to evaluate whether negative findings on CTA can reliably exclude aneurysms in patients with acute SAH., Materials and Methods: We conducted a retrospective analysis of all negative findings on CTAs performed from 2005 to 2009 in patients with spontaneous SAH. Findings were compared with DSA. CTAs were performed with a 64-section multidetector row CT scanner., Results: One hundred ninety-three patients with SAH and negative findings on CTA who underwent subsequent DSA were identified. The distribution of blood on unenhanced CT was the following: PMH in 93 patients, diffuse aneurysmal pattern in 50, no blood on CT (xanthochromic LP) in 32, and peripheral sulcal distribution in 18. All patients with PMH had negative findings on DSA. One patient with no blood on CT had vasculitis on DSA. Six of 18 (33%) patients with peripheral blood had vasculitis on DSA. Three of these were also diagnosed by CTA. All except 1 patient with diffuse aneurysmal blood had negative findings on DSA. One patient was diagnosed with an aneurysm on DSA (1/50, 0.5%). Repeat delayed DSA performed in 28 of these patients revealed a small aneurysm in 4 (14%). Five patients had a complication of DSA (2.6%); 1 was a clinical stroke (0.5%)., Conclusions: In patients with SAH, negative CTA findings are reliable in ruling out aneurysms in the PMH pattern or no blood on CT. DSA is indicated in the diffuse aneurysmal pattern of SAH, and repeat delayed DSA is required if the initial DSA findings are negative. When the blood is peripheral, CTA should be scrutinized for vasculitis and DSA is recommended for confirmation.

Epistaxis is a common condition that can be managed conservatively in most cases. When these measures, including anterior and posterior packing of the nasal cavity, are unsuccessful at controlling the bleeding, interruption of the blood supply to the sinonasal area can be performed, either by surgical ligation or by transarterial embolization. Embolization should be preceded by thorough diagnostic angiography. Aside from aiding with subsequent selective catheterization and embolization, such angiography may reveal significant anatomic anomalies, anastomoses, or an unsuspected cause of epistaxis. Taking these findings into account, the interventionalist may decide to refrain from embolization or adjust the technique to minimize the risk of adverse events, which are mostly related to inadvertent embolization of the internal carotid artery or ophthalmic artery. We present a review of the various causes of epistaxis and the treatment options, with emphasis on endovascular embolization. We also describe the protocol of our institution for endovascular management of this condition.

Background and Purpose: The diagnosis of dural arteriovenous fistula (DAVF) remains one of the few uncontested indications for catheter based cerebral angiography. We report our experience of using a commercially available form of time-resolved MR angiography (trMRA) at 3T for the diagnosis and classification of a cranial DAVF compared with the reference standard of digital subtraction angiography (DSA)., Materials and Methods: A retrospective review of our patient records identified patients who had undergone trMRA at 3T and DSA for the evaluation of DAVF. The trMRA consisted of whole-head, contrast-enhanced "time-resolved imaging of contrast kinetics" (TRICKS) MRA. Image sets were independently reviewed by 3 readers for the presence, location, and classification of a DAVF. The reported result of the DSA was used as the gold standard against which the performance of the trMRA was measured., Results: Forty patients were identified who had undergone DSA and trMRA for evaluation of DAVF, yielding a total of 42 cases. On DSA, the results of 7 cases were normal, 15 cases were performed for surveillance of a previously cured fistula, and a new fistula (14) or persistent (6) fistula was found in 20 cases. Of these 20 fistulas, on DSA, 13 were Borden I, 2 were Borden II, and 5 were Borden III. In 93% (39/42) of DAVF cases, the 3 readers were unanimous and correct in their independent interpretation of the trMRA, correctly identifying (or excluding) all fistulas and accurately classifying them when encountered., Conclusions: In this small series, trMRA at 3T seems be a reliable technique in the screening and surveillance of DAVF in specific clinical situations.

Background and Purpose: Endovascular embolization is a well-established treatment of ruptured intracranial aneurysms, but concern about its long-term stability and its ability to prevent rehemorrhage are still present. We evaluated the long-term clinical and angiographic follow-up of patients with ruptured cerebral aneurysms treated with coiling, focusing on rehemorrhage and changes in aneurysm morphologic features., Materials and Methods: A total of 377 patients with ruptured aneurysms that were treated with endovascular approaches at our institution between 1994 and 2008 were reviewed. Clinical and angiographic data were analyzed from a prospectively collected data base., Results: There were 377 patients with 391 ruptured aneurysms treated for 14 years. Good outcome (Glasgow Outcome Score [GOS], 5) was achieved in 74% of patients, moderate disability or poor outcome in 18%, and 8.8% died. Permanent morbidity or mortality from procedural complications occurred in 2.9%. Complete follow-up was available for 85% of surviving patients, with mean follow-up of 22.3 months. Re-treatment was required in 11% (31 patients). Eight (2.1%) patients had rebleeding, 6 (1.6%) in the hospital within 30 days of treatment, 5 in the first 48 hours. Follow-up imaging was available in 276 aneurysms in 270 patients. Recanalization occurred in 56 of 276 aneurysms (20.3%) regardless of the initial angiographic result, but the risk was higher if a body remnant was left (chi2, 11.791; P = .0006)., Conclusions: Long-term clinical and angiographic follow-up demonstrates the efficacy of endovascular treatment of ruptured intracranial aneurysms. Rebleeding after treatment is rare, with the greatest risk during the first 48 hours after treatment. Initial angiographic results are not a useful predictor of clinical outcome or rehemorrhage.

Background: Conventional arterial imaging focuses on the vessel lumen but lacks specificity because different pathologies produce similar luminal defects. Wall imaging can characterize extracranial arterial pathology, but imaging intracranial walls has been limited by resolution and signal constraints. Higher-field scanners may improve visualization of these smaller vessels., Methods: Three-tesla contrast-enhanced MRI was used to study the intracranial arteries from a consecutive series of patients at a tertiary stroke center., Results: Multiplanar T2-weighted fast spin echo and multiplanar T1 fluid-attenuated inversion recovery precontrast and postcontrast images were acquired in 37 patients with focal neurologic deficits. Clinical diagnoses included atherosclerotic disease (13), CNS inflammatory disease (3), dissections (3), aneurysms (3), moyamoya syndrome (2), cavernous angioma (1), extracranial source of stroke (5), and no definitive clinical diagnosis (7). Twelve of 13 with atherosclerotic disease had focal, eccentric vessel wall enhancement, 10 of whom had enhancement only in the vessel supplying the area of ischemic injury. Two of 3 with inflammatory diseases had diffuse, concentric vessel wall enhancement. Three of 3 with dissection showed bright signal on T1, and 2 had irregular wall enhancement with a flap and dual lumen., Conclusions: Three-tesla contrast-enhanced MRI can be used to study the wall of intracranial blood vessels. T2 and precontrast and postcontrast T1 fluid-attenuated inversion recovery images at 3 tesla may be able to differentiate enhancement patterns of intracranial atherosclerotic plaques (eccentric), inflammation (concentric), and other wall pathologies. Prospective studies are required to determine the sensitivity and specificity of arterial wall imaging for distinguishing the range of pathologic conditions affecting cerebral vasculature.

Introduction: A comprehensive evaluation of cranial magnetic resonance imagings (MRIs) of 23 patients with intracranial hypotension (IH) was performed, and the evolution of the abnormalities on follow-up MRIs was correlated with the clinical outcome., Materials and Methods: The MRI report database at the University Health Network in Toronto was searched, and 23 cases of IH were identified between 2001 and 2007. A retrospective review of the MRIs of the brain and the electronic patient chart was performed. A control group of 40 subjects was also selected to complement the analysis of the pituitary gland., Results: A positive venous distention sign (VDS) was observed in 23 out of 23 patients and was the first sign to disappear on early follow-up scans following successful treatment. Pachymeningeal enhancement was seen in 23 out of 23 patients, and pachymeningeal thickening was detectable on unenhanced fluid attenuation inversion recovery (FLAIR) sequences in 17 out of 23 patients (74%). An increase in pituitary size in IH was also demonstrated based on the measured pituitary height and was qualitatively detectable in 12 out of 21 (57%) patients as the protrusion of the pituitary gland above the sella turica (two postpartum patients were excluded from this analysis). Overall, there was good correlation between the imaging findings and clinical outcome following treatment., Conclusion: Accurate diagnosis and follow-up of IH should be possible is some patients on unenhanced MRI of the brain by combining the signs on FLAIR and sagittal T1W images, enabling timely diagnosis in unsuspected cases and avoiding unnecessary administration of gadolinium compounds. In addition, VDS might be useful for early assessment of response to treatment.

Background and Purpose: A substantial percentage of coiled aneurysms are associated with persistent filling of an aneurysmal component due to incomplete initial treatment or re-growth. Traditionally follow-up of coiled aneurysms has consisted of repeated intra-arterial cerebral catheter angiography, an invasive procedure with associated risks. Hence, many authors have advocated the use of non-invasive imaging techniques for this purpose. Our aim was to compare contrast-enhanced MR angiography (CE-MRA) with digital subtraction angiography (DSA) for depiction of aneurysmal remnants of coiled cerebral aneurysms., Materials and Methods: Aneurysms coiled between September 2003 and October 2006 were retrospectively reviewed. We included patients meeting the following criteria: 1) residual/recurrent aneurysm measuring 2 mm or greater, and 2) CE-MRA and DSA performed no more than 60 days apart. Three readers were asked to determine which technique was superior for characterization of the aneurysmal remnant: CE-MRA, DSA, or indeterminate. Statistical analysis included most rule and kappa statistics., Results: Of 232 patients who underwent coiling, 44 met the inclusion criteria (33 women and 11 men; 24-72 years of age). Sixteen patients had neck remnants and 28 had body remnants. The first study to identify the remnant was DSA in 35 patients and CE-MRA in 9. In 32 patients (32/44, 73%), the readers indicated that CE-MRA was superior to DSA for remnant characterization. CE-MRA and DSA were thought to be equivalent in 7 (16%), and DSA was preferred in 3 (7%). Two cases (5%) yielded ambiguous results. Of the 28 body remnants, 22 (78.6%) were characterized by remnant protrusion into the coil mass: In 20 of these (91%), the readers preferred CE-MRA over DSA, and in 2 cases (9%), the techniques were thought to be equivalent., Conclusion: In patients with known aneurysm remnants, CE-MRA is at least equivalent to DSA for characterization of aneurysmal remnants after coiling. Contrast filling within the coil mass was more clearly seen with CE-MRA than with DSA.

Background: Evaluation of the intracranial venous system has historically been performed with conventional catheter-based digital subtraction angiography (DSA). The continued importance of DSA can not be overstated in light of its inherent option of endovascular intervention and thrombolysis for cerebral venous thrombosis. DSA is, however, an invasive procedure with associated risks, including radiation exposure, and adverse effects of iodinated contrast medium. DSA also suffers from the limitations of 2-dimensional planar imaging. For these reasons, noninvasive imaging techniques are playing a greater role in evaluation of the intracranial venous system., Review Summary: This review provides an overview of the current noninvasive methods and their applications and limitations, with examples of their use in a variety of disease processes. Computed tomography venography (CTV) is discussed as well as the various types of cerebral magnetic resonance venography (MRV)., Conclusion: When available, MR supplemented with the technique of triggered gadolinium-enhanced MRV is the method of choice for the diagnosis of dural sinus thrombosis as well as most other pathologic entities affecting the intracranial venous system.

Introduction: Our objective was to define the appearance and distribution of normally occurring intraluminal structures within the dural venous sinuses on contrast-enhanced MR venography (CE-MRV)., Methods: Informed consent was obtained from all subjects participating in the study, and the study protocol was approved by the institutional review board of the University Health Network. A group of 56 patients underwent CE-MRV. Intraluminal structures were categorized as an arachnoid granulation (AG) or trabeculation (Willis cord). Willis cords within the transverse and sigmoid sinuses as well as AGs 4 mm or more in size were recorded., Results: In 20 of the 56 patients (36%), 29 AGs measuring 4 mm or more were identified within the dural sinuses. All AGs were spherical or ovoid and occurred at sites where a cortical vein joined a dural sinus. Nearly all AGs (28 of 29, 97%) displayed an eccentric internal vein. Willis cords were seen within the superior sagittal sinus in all patients. Willis cords were less prevalent in the remaining dural sinuses. A minimum of one Willis cord was seen in 58 of the 112 transverse sinuses (52%). These cords were 1-2 mm in maximal thickness, uniformly smooth, and commonly partitioned the sinus. Willis cords and AGs (of any size) were not encountered within the sigmoid sinuses or jugular veins., Conclusion: CE-MRV elucidates structures normally found within the dural sinuses. These consist of AGs and Willis cords. This report confirms and establishes new criteria for identification of these normally occurring intraluminal structures providing a basis for their differentiation from pathologic entities.

Background and Purpose: Patients with intracranial hypotension (IH) demonstrate intracranial venous enlargement with a characteristic change in contour of the transverse sinus seen on routine T1-weighted sagittal imaging. In IH, the inferior margin of the midportion of the dominant transverse sinus acquires a distended convex appearance; we have termed this the venous distension sign (VDS). This is distinct from the normal appearance of this segment, which usually has a slightly concave or straight lower margin. This sign is introduced, and its performance as a test for the presence of this disease is evaluated., Materials and Methods: The transverse sinuses on T1-weighted sagittal imaging of 15 patients with IH and 15 control patients were independently assessed in a blinded fashion by 3 readers for the presence of a VDS. A present or absent VDS was determined for each patient by each reader, and a consensus result for each patient was determined by unanimity or majority rule., Results: Using the VDS, the readers correctly identified 93% (14 of 15) of the IH patients and similarly 93% (14 of 15) of the control patients. There was a high rate of agreement among the readers for the interpretation of the VDS (multirater kappa = 0.82). The overall sensitivity of the VDS for the diagnosis of intracranial hypotension was 94%. Specificity was also 94%., Conclusion: The VDS appears to be an accurate test for the presence or absence of IH and may be helpful in the evaluation of these patients.

Introduction: To evaluate the clinical role of CT angiography (CTA) in patients with acute subarachnoid hemorrhage (SAH) for treatment decision-making., Methods: Consecutive patients with acute SAH had CTA using a 64-slice scanner for initial clinical decision-making. Image processing included multiplanar volume reformatted (MPVR) maximum intensity projections (MIP) and 3D volume-rendered reconstructions. CTAs were used for (1) evaluating the cause of SAH, and (2) triaging aneurysm-bearing patients to the more appropriate management, either surgical clipping or endovascular coiling. CTA findings were confirmed by neurosurgical exploration or catheter angiography (digital subtraction angiography, DSA). Successful coiling provided evidence that triaging to endovascular treatment was correct., Results: Included in the study were 73 patients. CTA findings were confirmed by DSA or neurosurgical operation in 65 patients, and of these 65, 47 had aneurysmal SAH, 3 had vasculitis, 1 had arterial dissection and 14 had no underlying arterial abnormality. The cause of SAH was detected with CTA in 62 out of the 65 patients (95.4%, sensitivity 94%, specificity 100%). CTA revealed the aneurysm in 46 of 47 patients (98%, sensitivity 98%, specificity 100%, positive predictive value 100%, negative predictive value 82.3%), 1 of 3 vasculitides and 1 of 1 dissection. Of the 46 patients with aneurysm, 44 (95.7%) were referred for treatment based on CTA. In 2 patients (2 of 46, 4.4%) CTA was not informative enough to choose treatment requiring DSA. Of the 44 patients, 27 (61.4%) were referred to endovascular treatment and successful coiling was achieved in 25 (25 of 27, 92.6%)., Conclusion: CTA using a 64-slice scanner is an accurate tool for detecting and characterizing aneurysms in acute SAH. CTA is useful in the decision process whether to coil or clip an aneurysm.

The aim of this study was to evaluate the accuracy of previously reported neuroimaging signs in establishing or excluding the diagnosis of idiopathic intracranial hypertension (IIH). In a retrospective study, 30 patients with confirmed IIH and 56 controls were evaluated with brain magnetic resonance imaging. All examinations were evaluated in a blinded fashion by three neuroradiologists for the presence or absence of the 'traditional' signs of IIH: empty sella turcica, deformation of the pituitary, slit-like ventricles, 'tight' subarachnoid spaces, flattening of the posterior globe, protrusion of the optic nerve, enhancement of the optic nerve head, distension of the optic nerve sheath and vertical tortuosity of the optic nerve. Optic nerve protrusion and enhancement, slit-like ventricles and tight cerebrospinal fluid spaces were not significantly associated with IIH (P>0.05). Posterior globe flattening, optic nerve sheath distension, optic nerve tortuosity, pituitary deformity and empty sella turcica were significantly associated with IIH (P<0.05). However, most of these are not helpful in a clinical setting, with the exception of posterior globe flattening. This is the only sign that, if present, strongly suggests the diagnosis of IIH (specificity 100%, 95% CI 93.6% to 100%; sensitivity 43.5%, 95% CI 27.3% to 60.8%; positive likelihood ratio 49.7). The majority of the reported signs for IIH on cross-sectional imaging are not helpful in establishing or excluding the diagnosis of IIH, and are of no value in the clinical setting. Flattening of the posterior aspect of the globe is the only sign that, if present, is suggestive of the diagnosis of IIH.

Purpose: To generate two separate three-dimensional (3D) high spatial resolution images of the intracranial arterial and venous systems using a single contrast injection., Materials and Methods: A 3D contrast-enhanced (CE) magnetic resonance angiography (MRA) acquisition was modified to create two separate k-space data sets to encode the arterial and venous enhancement signals individually after contrast agent injection. Following an automated detection of contrast arrival, the central k-space views corresponding to the arterial phase were acquired for the first eight seconds. A full elliptical-centric acquisition was then acquired for the venous phase and the missing views in the periphery of the first k-space data set were copied from the venous phase. A total of 18 patients underwent this study. Image quality, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were determined in both intracranial systems., Results: Two 3D image sets were generated for the arterial and venous intracranial systems. Both sets have high quality images that are clinically diagnostic. SNR and CNR were high in both sets, so that all the major vessels were visible., Conclusion: This technique provides images with high spatial resolution for both arterial and venous intracranial systems using a single contrast injection.

Traditionally, the primary role of imaging in the diagnosis of idiopathic intracranial hypertension (IIH) has been to exclude other conditions that can cause increased intracranial pressure (ICP) and papilledema. Over the years multiple attempts have been made to define objective signs on cross-sectional imaging as well as on cerebral angiography that would actually identify IIH patients rather than only exclude other underlying conditions. There was also hope that mechanism-derived' imaging techniques such as magnetic resonance venography (MRV) and diffusion weighted imaging would potentially provide insight into the still unknown underlying etiology of this disease. It was recently shown in a double blind controlled study that flattening of the posterior aspect of the globe is the only sign on cross-sectional imaging that, if present, strongly suggests the diagnosis of IIH. In addition, evaluation of extra-luminal and intra-luminal narrowing of the transverse and sigmoid dural sinuses with contrast enhanced MRV using a simple grading system provides a highly sensitive and specific test for identifying patients with IIH. Unfortunately none of the imaging based studies published to date can explain the pathogenesis of IIH whether it be a primary vascular venous disorder causing the increase in ICP or rather the disorder itself secondarily affecting the cerebral veins.

This 39-year-old man presented with a 6-month history of occipital headaches. Magnetic resonance imaging revealed an irregularly shaped fourth ventricle mass. One month after his initial presentation, he was admitted to the hospital with significant tumor expansion and clinical deterioration. A posterior fossa craniectomy was performed and the mass was resected. Histopathological analysis of this tumor showed central necrosis with associated edema in an otherwise typical and benign-appearing subependymoma. To the authors' knowledge, this is the first reported case of rapid, nonhemorrhagic expansion associated with necrosis in a previously asymptomatic subependymoma.

Two MRA techniques were evaluated for the follow-up of coiled intracranial aneurysms. Twenty-nine coiled aneurysms were evaluated for a total of 36 follow-up assessments using 3D time-of flight MRA (TOF MRA), an auto-triggered elliptic-centric-ordered three-dimensional gadolinium-enhanced MR angiogram (ATECO MRA), as well as a selective digital subtraction angiography (DSA), which served as the "gold standard". Confident visualization was seen in 36 (100%) of ATECO MRAs and in 32 (89%) of the TOF MRAs. Eleven residual aneurysm components (RACs) greater than 2 mm were described on DSA. Of these, nine were seen on ATECO MRA (sensitivity of 81% and specificity of 88%) and four were seen on TOF MRA (sensitivity of 40% and specificity of 90%). The two RACs not seen on ATECO MRA both measured 3 mm. The six RACs not seen on TOF MRA measured 3, 4 and 5 mm. ATECO MRA provides a non-invasive reliable angiogram for the surveillance of coiled aneurysms and is superior to TOF MRA for this purpose.

We present a series of three patients with mastoid air cell effusions associated with adjacent lateral sinus thrombosis. In all of these cases, the findings support the hypothesis that the mastoid effusion is secondary to sinus thrombosis rather then the other way around. Also shown is the chronology and natural evolution of mastoid air cell effusion secondary to sinus thrombosis as seen on planar imaging.

In-plane carotid artery motion during a 3D MR angiography (MRA) scan can significantly degrade the resulting image resolution. This study characterizes the effect of cardiac pulsatility on 3D contrast-enhanced (CE) MRA with elliptical centric acquisitions using a point-spread function (PSF) analysis. Internal carotid artery (ICA) motion was collected from volunteers and patients using both MR and ultrasound (US) scans. After measuring the carotid artery motion displacement, a simulation was performed which calculated the blurring effects for three different protocols: nongated and two different cardiac gating schemes. The motion sensitivity of each protocol was evaluated for different spatial resolutions. The selection of optimal imaging parameters for a given scan time was investigated. The final results showed that cardiac-gated acquisitions only over a limited region of k-space high spatial frequencies are more time-efficient than cardiac gating for the entire k-space, as it allows for higher resolutions to be achieved and for capturing the arterial phase with low spatial frequencies. Selecting the optimal gating parameters depends directly on the motion characteristics of each individual. Our initial clinical experience is presented, and the need for a real-time tool that characterizes motion behavior for each individual as a prescan protocol is discussed., (Copyright 2004 Wiley-Liss, Inc.)

We report a patient with extensive cerebral venous thrombosis who showed complete reversal of restricted diffusion on MRI, accompanied by excellent clinical recovery. The implications of these findings in relation to interpretation of diffusion changes in cerebral venous thrombosis are discussed, and differences with arterial stroke are highlighted.

Objective: To determine the prevalence and nature of sinovenous obstruction in idiopathic intracranial hypertension (IIH) using auto-triggered elliptic-centric-ordered three-dimensional gadolinium-enhanced MR venography (ATECO MRV)., Methods: In a prospective controlled study, 29 patients with established IIH as well as 59 control patients underwent ATECO MRV. In a randomized blinded fashion, three readers evaluated the images. Using a novel scoring system, each reader graded the degree of stenosis seen in the transverse and sigmoid sinuses of each patient., Results: There was excellent agreement across the three readers for application of the grading system. Substantial bilateral sinovenous stenoses were seen in 27 of 29 patients with IIH and in only 4 of 59 control patients., Conclusion: Using ATECO MRV and a novel grading system for quantifying sinovenous stenoses, the authors can identify IIH patients with sensitivity and specificity of 93%.

Purpose: To prospectively identify risk factors for neurologic complications related to cerebral angiography., Materials and Methods: A total of 2,899 consecutive cerebral digital subtraction angiograms obtained with nonionic contrast material were prospectively evaluated. Neurologic complications were categorized as transient (<24 hours), reversible (24 hours to 7 days), and permanent (>7 days). The neurologic complication rate was correlated with patient age, type of indication for catheter angiography, medical history, fluoroscopic time, number and size of catheters, type and number of vessels injected, operator experience, and the quartile in which the study was performed. The correlations were statistically analyzed with Fisher exact tests and a multiple logistic regression model., Results: There were 39 (1.3%) neurologic complications in 2,899 procedures; 20 were transient (0.7%), five (0.2%) were reversible, and 14 (0.5%) were permanent. Neurologic complications were significantly more common in patients 55 years of age or older (25 of 1,361; 1.8%) (P =.035), in patients with cardiovascular disease (CVD) (20 of 862; 2.3%) (P =.004), and when fluoroscopic times were 10 minutes or longer (24 of 1,238; 1.9%) (P =.022). The neurologic complication rate was higher in procedures performed by fellows alone (24 of 1,878; 1.3%) compared with that when staff alone performed the procedures (three of 598; 0.5%), but the difference was not significant (P =.172). Neurologic complications were lower in the fourth quartile of the study (six of 171; 0.9%) compared with the first quartile (16 of 776; 2.1%), which was likely due to fewer patients being examined for carotid stenosis or ischemic stroke and fewer patients with CVD (P =.085)., Conclusion: Age-related vascular disease accounted for the failure to lower the neurologic complication rate of cerebral angiography despite technical advances., (Copyright RSNA, 2003)

The intracranial venous system is a complex three-dimensional structure that is often asymmetric and considerably more variable than the arterial anatomy. The traditional approach has been to evaluate venous phase of catheter angiography. However, non-invasive imaging is now playing a greater role in evaluating the intracranial venous system in both healthy and diseased states. MR angiography, and especially Gd-enhanced 3D MRA, has recently emerged and offers excellent visualization of venous morphology from multiple orientations. An overview of the current non-invasive MRA methods and their applications has been provided during depiction of normal venous anatomy.

Purpose: To evaluate gadolinium-enhanced three-dimensional auto-triggered elliptic centric-ordered (ATECO) magnetic resonance (MR) venography for imaging of the intracranial venous system., Materials and Methods: ATECO MR venography was performed in 23 patients, eight of whom also underwent two-dimensional time-of-flight (TOF) MR venography for imaging of the intracranial venous system. Seventeen predefined venous structures were evaluated on all venograms by two neuroradiologists. Visualization of venous structures was defined as completely visible (including clearly pathologic), partially visible, or not visible. Readers were also asked to compare the visibility of these predefined structures on ATECO and TOF MR venograms, where available., Results: Of the 23 patients, six had dural venous sinus disease. Of the remaining 17 healthy patients, five underwent both ATECO and TOF MR venography and 12 underwent ATECO MR venography alone. On ATECO MR venograms obtained in the healthy patients, visibility of the 17 predefined venous structures was complete in 92% (531 of 578) of evaluations. For the five normal TOF MR venograms, the rate of complete visibility of the same venous structures was 61% (104 of 170). The rate of complete visibility of the large dural venous sinuses was 99% for ATECO MR venograms and 75% for TOF MR venograms., Conclusion: ATECO MR venography provides high-quality images of the intracranial venous anatomy and was superior to TOF MR venography for consistent complete visibility of venous structures., (Copyright RSNA, 2002)

Background and Purpose: In the early 1980s, it was demonstrated that surgical intradural division of the shunting vein to the medullary venous plexus cures a spinal dural arteriovenous fistula (DAVF) at low morbidity. There is, however, growing literature to support endovascular therapy., Methods: The clinical features of 49 consecutive patients with a spinal DAVF treated at a single institution between 1986 and 2001 were studied (mean age, 63 years; range, 28 to 78 years; 80% male). When possible, embolization was offered as the initial treatment. Endovascular treatment was considered adequate only if the proximal shunting vein could be occluded with liquid adhesive embolics. Motor and bladder function was evaluated with Aminoff scores an average of 32.3 months after treatment., Results: All but 1 patient presented with myelopathy. At a mean of 2.3 years after symptom onset, 48 DAVFs were angiographically demonstrated. Since 1999, gadolinium-enhanced MR angiography was additionally performed in 7 patients to point out the level of the DAVF. Endovascular embolization could be attempted in 44 of the 48 DAVFs and resulted in a cure in 11 (25%). Thirty-five DAVFs were surgically cured; 2 patients refused surgery after failed embolization. Angiographic confirmation of the treatment result was available in 97.7% of the patients. No permanent complications of either embolization or surgery were noted. Motor and bladder function scores were significantly improved in 35 patients who had long-term follow-up (both P<0.005)., Conclusions: Endovascular treatment with liquid adhesive material provided a result equal to surgery in 25% of patients, overall resulting in a significant amelioration in the neurological status of patients with a spinal DAVF.

Nine patients with initial magnetic resonance (MR) imaging and clinical findings suggestive of spinal dural arteriovenous fistula (AVF) underwent spinal MR angiography with an autotriggered elliptic centric ordered three-dimensional gadolinium-enhanced technique (hereafter, this MR angiographic technique) before conventional intraarterial angiography. In all nine patients, findings with this MR angiographic technique correctly and precisely localized the spinal dural AVF. Observer error resulted in one case in which the site of the fistula was not prospectively reported but was easily identified retrospectively on the spinal MR angiogram.

Auto-triggered elliptic centric-ordered three-dimensional (3D) gadolinium-enhanced magnetic resonance (MR) angiography was compared with 3D multiple overlapping thin-slab acquisition time-of-flight (TOF) MR angiography in the evaluation of intracranial arteriovenous malformations (AVMs) in 10 patients. Intraarterial digital subtraction angiography (DSA) was the reference standard. Gadolinium-enhanced MR angiograms were found to be equivalent to DSA images in AVM component depiction in 70%--90% of cases and were consistently superior to TOF MR angiograms.

At magnetic resonance angiography in nine patients, a test bolus of gadopentetate dimeglumine was injected to determine transit time from venous injection to arrival in the carotid arteries. Mean times to onset of enhancement were calculated (arterial, 15.7 seconds [range, 10-22 seconds]; venous, 23.4 seconds [range, 16-30 seconds]; optimal imaging time, 7.78 seconds [range, 6-10 seconds]). Transit time was calculated correctly with a test bolus examination.

Purpose: To determine the magnetic resonance (MR) imaging characteristics of amyotrophic lateral sclerosis (ALS) and to evaluate possible correlations between the disease severity and the MR imaging findings., Materials and Methods: The authors retrospectively reviewed MR images of the head in 17 patients with ALS (14 men and three women) and 17 age-matched control subjects. The corticospinal tract (CST) was analyzed for the following features: size, signal intensity, and number of sections and regions in which the CST could be seen., Results: Patients with ALS demonstrated sharp, well-defined, round, symmetric lesions that were hyperintense to gray matter within the CST. The lesions were best seen at the level of the middle or lower internal capsule on T2-weighted images. Visualization of the CST on proton-density-weighted images (which occurred in eight ALS patients) is the most reliable MR finding. Low signal intensity was identified within the motor cortex in six patients. Positive MR findings correlated with average or rapid progression of the disease., Conclusion: Increased signal intensity in the CST on proton-density-weighted MR images is diagnostic for motor neuron disease and correlates with the rate of disease progression. Subtle ALS changes can be differentiated from the normal CST. Low signal intensity in the motor cortex on T2-weighted images is a useful finding.