Differentiation Between the Low and High Trans-Stenotic Pressure Gradient in Patients With Idiopathic Intracranial Hypertension Using 4D Flow MRI-Derived Hemodynamic Parameters.

BACKGROUND: Trans-stenotic pressure gradient (TPG) measurement is essential for idiopathic intracranial hypertension (IIH) patients with transverse sinus (TS) stenosis. Four-D flow MRI may provide a noninvasive imaging method for differentiation of IIH patients with different TPG. PURPOSE: To investigate the associations between 4D flow parameters and TPG, and to evaluate the diagnostic performance of 4D flow parameters in differentiating patients with high TPG (GroupHP) from low TPG (GroupLP). STUDY TYPE: Prospective. POPULATION: 31 IIH patients with TS stenosis (age, 38 ± 12 years; 23 females) and 5 healthy volunteers (age, 25 ± 1 years; 2 females). FIELD STRENGTH/SEQUENCE: 3T, 3D phase contrast MR venography, and gradient recalled echo 4D flow sequences. ASSESSMENT: Scan-rescan reproducibility of 4D flow parameters were performed. The correlation between TPG and flow parameters was analyzed. The netflow and velocity difference between inflow plane, outflow plane, and the stenosis plane were calculated and compared between GroupHP and GroupLP. STATISTICAL TESTS: Pearson's correlation or Spearman's rank correlation coefficient, Independent samples t-test or Wilcoxon rank-sum test, Intra-class correlation coefficient (ICC), Bland-Altman analyses, Receiver operating characteristic curves. A P value <0.05 was considered significant. RESULTS: Significant correlations were found between TPG and netflow parameters including Favg,out-s, Favg,in-s, Fmax,out-s, and Fmax,in-s (r = 0.525-0.565). Significant differences were found in Favg,out-s, Fmax,out-s, Favg,in-s, and Fmax,in-s between GroupHP and GroupLP. Using the cut-off value of 2.19 mL/sec, the Favg,out-s showed good estimate performance in distinguishing GroupHP from GroupLP (AUC = 0.856). The ICC (ranged 0.905-0.948) and Bland-Altman plots indicated good scan-rescan reproducibility. DATA CONCLUSIONS: 4D flow MRI derived flow parameters showed good correlations with TPG in IIH patients with TS stenosis. Netflow difference between outflow and stenosis location at TS shows the good performance in differentiating GroupHP and GroupLP cases. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Multiple skull base defects in the setting of spontaneous cerebrospinal fluid rhinorrhea; a dual institution view.

PURPOSE: Idiopathic intracranial hypertension (IIH) is a condition of high cerebrospinal fluid (CSF) pressure that presents with CSF leak. The implications of multiple skull base defects (SBD) and associated synchronous CSF leaks have not been previously explored. MATERIALS AND METHODS: A dual institutional case-control study examined multiple SBD's and encephaloceles on the risk of CSF leak and postoperative failures post-repair. IIH patients with CSF leaks and IIH controls without leaks were selected retrospectively. Chi square analysis evaluated for statistically significant alterations in probability with CSF leak development. RESULTS: 192 patients were selected with 108 IIH controls and 84 spontaneous CSF leak cases. Signs and symptoms for IIH controls and CSF leak cases respectively were pulsatile tinnitus (60.2 % and 29.8 %), headaches (96.3 % and 63.1 %), papilledema (74.1 % and 12.5 %), visual field defects (60.8 % and 13 %) (p < 0.001). Encephalocele formation in controls was 3.7 % compared to cases at 91.6 % (p < 0.001). Multiple SBD's in controls compared cases was 0.9 % and 46.4 % respectively (p < 0.001). Subgroup analysis of CSF leak cases showed 15 patients with two CSF leak repairs due to a recurrence. 27 (39.1 %) single leak cases had multiple SDB's while 12 (80 %) recurrent leaks had multiple SDB's (p = 0.004). CONCLUSIONS: Patients with radiographic evidence of multiple SBD's and encephaloceles represent a high-risk population with a propensity for CSF leaks. Secondary SBD's are common in patients with spontaneous CSF rhinorrhea and higher in patients with a recurrence.

Angulation of the dural venous sinuses of the posterior cranial fossa: Anatomical study with clinical and surgical applications.

Cerebral vein and dural venous sinus thromboses (CVST) account for 0.5%-1% of all strokes. Some structural factors associated with a potentially higher risk for developing CVST have been described. However, angulation of the dural venous sinuses (DVS) has yet to be studied as a structural factor. The current study was performed because this variable could be related to alterations in venous flow, thus predisposing to a greater risk of CVST development. Additionally, such information could help shed light on venous sinus stenosis (VSS) at or near the transverse-sigmoid junction. The angulations formed in the different segments of the grooves of the transverse (TS), sigmoid (SS), and superior sagittal sinuses (SSS) were measured in 52 skulls (104 sides). The overall angulation of the TS groove was measured using two reference points. Other variables were examined, such as the communication pattern at the sinuses' confluence and the sinus grooves' lengths and widths. The patterns of communication between sides were compared statistically. The most typical communication pattern at the sinuses' confluence was a right-dominant TS groove (82.98%). The mean angulations of the entire left TS groove at two different points (A and B) were 46° and 43°. Those of the right TS groove were 44° and 45°. The median angulations of the left and right SSS-transverse sinus junction grooves were 127° and 124°. The mean angulations of the left and right TS-SSJsv grooves were 111° (range 82°-152°) and 103° (range 79°-130°). Differentiating normal and abnormal angulations of the DVSs of the posterior cranial fossa can help to explain why some patients are more susceptible to pathologies affecting the DVSs, such as CVST and VSS. Future application of these findings to patients with such pathologies is now necessary to extrapolate our results.

Impact of rater experience and referral question on detecting magnetic resonance imaging features of idiopathic intracranial hypertension.

BACKGROUND AND PURPOSE: In idiopathic intracranial hypertension (IIH), magnetic resonance imaging (MRI) features are promising diagnostic markers, but the impact of rater experience and the specific referral question is unknown. METHODS: From the Vienna Idiopathic Intracranial Hypertension database, patients were included with definitive IIH and routine cranial MRI performed during diagnostic work-up. Frequencies of partial empty sella (ES), optic nerve sheath distension (ONSD), optic nerve tortuosity (ONT), posterior globe flattening (PGF) and transverse sinus stenosis (TSS) were compared in three settings: (i) real-world rating, (ii) junior neuroradiologist without special IIH training and (iii) senior neuroradiologist with experience in IIH imaging (gold standard). RESULTS: Magnetic resonance imaging scans of 84 IIH patients (88% female, mean age 33.5 years) were evaluated. By gold standard, ONSD was the most frequent (64.3%) followed by TSS (60.0%), ONT (46.4%), ES (44.4%) and PGF (23.8%). Compared to the gold standard, IIH features were described significantly less frequently in routine MRI reports (ONSD 28.6%, ONT 13.1%, PGF 4.8%, TSS 42.9%, p < 0.01 respectively) except for ES (42.9%, p = 0.9). A specific referral question regarding IIH increased detection rates in routine reports, but rates remained significantly lower than by gold standard. In contrast, a rating by a neuroradiologist without special training produced significantly higher frequencies of ONSD (81.0%, p < 0.01) and ONT (60.7%, p < 0.01) but not of ES (47.6%), PGF (29.8%) and TSS (68.1%). CONCLUSIONS: Idiopathic intracranial hypertension MRI features are underestimated in routine MRI reports and partly overcalled by less experienced neuroradiologists, driven by features less well known or methodologically difficult. Reevaluation of MRI scans by an experienced rater (and to a lesser degree a specific referral question) improves diagnostic accuracy.

Can the sigmoid notch sign be used on cranial computed tomography to differentiate between thrombosis and hypoplasia of the cerebral transverse venous sinus?

OBJECT: In patients with headache, the distinction between transverse sinus (TS) atresia/hypoplasia and TS thrombosis in cranial magnetic resonance venography (MRV) may be misleading. In this study, we aimed to distinguish TS thrombosis from atretic or severely hypoplastic TS, with the help of cranial computed tomography (CT). METHOD: Non-contrast cranial CT scans of 51 patients with no or severely thin signal on MRV were analyzed retrospectively using the bone window. Absence or asymmetry of the sigmoid notches on the CT predicted atretic or severe hypoplastic TS, and symmetry predicted thrombotic TS. Afterwards, it was investigated whether the patient's other imaging findings and confirmed diagnoses matched with the predictions. FINDINGS: Of the 51 patients included in the study, 15 were diagnosed with TS thrombosis, and 36 were diagnosed with atretic/hypoplastic TS. All 36 of the congenital atresia/hypoplasia diagnoses were correctly predicted. Thrombosis was predicted correctly in 14 of 15 patients with TS thrombosis. In cranial CT, the symmetry or asymmetry of the sigmoid notch sign was examined, and it was found that the evaluation predicted with 93.3% sensitivity (95% confidence interval (CI): 68.05-99.83) and 100% specificity (95% CI: 90.26-100.00) the distinction between TS thrombosis and atretic/hypoplastic sinus. CONCLUSION: Symmetry or asymmetry of the sigmoid notch on CT is a reliable method that can be used to differentiate congenital atresia/hypoplasia from the TS thrombosis in patients with very thin or absent TS signal on the cranial MRV.

Catastrophic Outcome Following Apparently Trivial Nondominant Transverse Sinus Injury During Resection of a Tentorial Meningioma: Case Report.

A 52-year-old man was admitted to our hospital with symptoms of raised intracranial pressure and cerebellar dysfunction caused by a medium-sized (4 cm in diameter) tentorial meningioma with an infratentorial extension. Preoperative magnetic resonance imaging showed that the tumor indented and possibly partially invaded the adjacent junction of the nondominant transverse and sigmoid sinuses. The contralateral dominant transverse sinus was fully patent. Total surgical removal of the lesion was done through the left retrosigmoid approach. During dissection of the meningioma, some bleeding from the venous sinus was noted, which was easily controlled by packing with hemostatic materials. The initial postoperative period was unremarkable, but approximately 48 h after surgery, acute clinical deterioration caused by hemorrhagic venous infarction of the left cerebellar hemisphere and brain stem developed and necessitated urgent reoperation for the evacuation of hematoma and brain decompression. Thereafter, the patient remained in a prolonged coma with a severe neurological deficit. After several years of extensive neurorehabilitation, he was able to walk with support but had a tracheostomy, required a feeding tube, and voided with a urinary catheter. Such a catastrophic outcome after an apparently trivial nondominant transverse sinus injury during resection of a tentorial meningioma raises the question whether reconstruction of the sinus wall with preservation of its patency might have prevented this complication in our patient.

ICP during head movement: significance of the venous system.

BACKGROUND: It is thought that the internal jugular veins (IJV) are the primary route for cranial venous outflow in supine position and the vertebral venous plexus when upright. Previous studies have noted a greater increase in intracranial pressure (ICP) when subjects turn their head in one direction compared to the other, but no clear cause had been investigated. We hypothesised that in the supine position, head turning and consequently obstructing the IJV draining the dominant transverse sinus (TVS) would lead to a greater rise in ICP compared to turning to the non-dominant side. METHODS: A prospective study in a large-volume neurosurgical centre. Patients undergoing continuous ICP monitoring as part of their standard clinical management were recruited. Immediate ICP was measured in different head positions (neutral, rotated to the right and left) when supine, seated, and standing. TVS dominance was established by consultant radiologist report on venous imaging. RESULTS: Twenty patients were included in the study, with a median age of 44 years. Venous system measurements revealed 85% right-sided vs 15% left-sided dominance. Immediate ICP rose more when head turning from neutral to the dominant TVS (21.93mmHg ± 4.39) vs non-dominant side (16.66mmHg ± 2.71) (p= <0.0001). There was no significant relationship in the sitting (6.08mmHg ± 3.86 vs 4.79mmHg ± 3.81, p = 0.13) or standing positions (8.74mmHg ± 4.30 vs 6.76mmHg ± 4.14, p =0.07). CONCLUSION: This study has provided further evidence that the transverse venous sinus to internal jugular system pathway is the likely primary venous drainage when supine; and quantified its effect when head turning on ICP. It may guide patient-specific nursing care and advice.

Micro-Doppler for venous sinus localization in approaches to the cerebello-pontine angle.

BACKGROUND: Main anatomical landmarks of retrosigmoid craniotomy are transverse sinus (TS), sigmoid sinus (SS), and the confluence of both. Anatomical references and guidance based on preoperative imaging studies are less reliable in the posterior fossa than in the supratentorial region. Simple intraoperative real-time guidance methods are in demand to increase safety. METHODS: This manuscript describes the localization of TS, SS, and TS-SS junction by audio blood flow detection with a micro-Doppler system. CONCLUSION: This is an additional technique to increase safety during craniotomy and dura opening, widening the surgical corridor to secure margins without carrying risks nor increase surgical time.

Absence of the torcular, review of venous sinus anatomy, and the simplified dural sinus classification.

BACKGROUND: Classically, the torcular Herophili is described as the symmetric junction between the superior sagittal sinus (SSS), transverse sinuses (TSs), and straight sinus (SS). However, finding this pattern in practice is not standard. Anatomical variations are common, and different drainage patterns should be expected. Existing literature proposes highly detailed descriptions and classifications of this region. Still, a simplified and practical categorization is not available. METHODS: We present an anatomical finding of the torcular Herophili discovered on a cadaveric dissection. Then, we conducted a retrospective study examining the 100 most recent cranial magnetic resonance venographies (MRVs) from the Mayo Clinic, labeling them with a new proposed dural sinus classification system. Images were initially classified by two authors and further validated by a board-certified neurosurgeon and a board-certified neuroradiologist from our institution. To measure consistency in image identification, two additional international neurosurgeons were asked to classify a subset of the same MRV images, and their answers were compared. RESULTS: Of the MRV cohort, 33 patients were male and 67 were female. Their ages ranged from 18 to 86 years, with a mean of 47.35 years and a median of 49 years. Upon examination, 53 patients presented as confluent (53%), 9 as SSS divergent (9%), 25 as SS divergent (25%), 11 as circular (11%), and 2 as trifurcated (2%). The inter-rater reliability ranked very good; agreement between the two neurosurgeons was 83% (κ = 0.830, p < 0.0005). CONCLUSION: The confluence of the venous sinuses is a highly variable anatomical area that is rarely evaluated with neuroimaging before surgery. The classic textbook configuration is not the rule. Using a simplified classification system may increase awareness and hopefully patient safety by preparing the physician for anatomical variations that they will encounter in a surgical or clinical scenario.

Transverse sinus pathologies, vestibular migraine and intracranial hypertension without papilledema.

BACKGROUND: In the absence of papilledema, the presentation of migraine and idiopathic intracranial hypertension (IIH) is very similar. In this respect, an IIH could be presented as a vestibular migraine. Our main objective in this case report is to demonstrate the similarities between IIH and vestibular migraine. CASES: This is a report of 14 patients who have IIH without papilledema presented as vestibular migraine to the clinic and followed from 2020 to 2022. RESULTS: The common presentation of patients was ear-facial pain, dizziness, and frequent pulsatile tinnitus. One-fourth of the patients reported episodes of true episodic vertigo. The average age was 37.8, the average BMI was 37.4, and the average lumbar puncture-opening pressure was 25.6 cm H2O. Transverse sinus venous flow alterations caused neuroimaging findings of sigmoid sinus dehiscence, empty sella, or tonsillar ectopia. Most patients improved with carbonic anhydrase inhibitors, and one patient was treated with a dural sinus stent. CONCLUSION: A transverse sinus stenosis, even in the non-dominant site, may elevate the CSF pressure in obese individuals. This stenosis causes dural sinus-related pulsatile tinnitus with characteristics different from those of an arterial origin. Dizziness is a common complaint in patients with IIH, just like VM. In our opinion, episodic vertigo in these patients is the direct effect of CSF flow alterations into the inner ear's vestibule. Patients with mild elevations will be presented to the clinic, similar to migraines with or without the presence of pulsatile tinnitus. Treatment requires lowering intracranial pressure and managing migraine symptoms.

Transsinusal embolization of transverse sigmoid sinus dural arteriovenous fistula in a hybrid operating room: A technical note.

BACKGROUND: Using the transverse sinus as a conduit to treat a transverse sigmoid sinus dural arteriovenous fistula is uncommon. This report describes a minimally invasive direct puncture technique for the transverse sinus to treat a complex dural arteriovenous fistula in a hybrid operating room. CASE: The patient was a 64-year-old man with intractable status epilepticus. Digital subtraction angiography demonstrated a right transverse sigmoid sinus dural arteriovenous fistula (Borden type II, Cognard type IIa+b). We performed a transcranial direct puncture because the femoral vein approach was not feasible due to bilateral thrombosed sinuses. Under general anesthesia and park-bench patient positioning, the transverse sinus was exposed and catheterized, and the affected sinus was embolized using microcoils. The fistula was completely obliterated, resolving the status epilepticus. CONCLUSIONS: Direct puncture of the transverse sinus can be effective for treating a transverse sigmoid sinus dural arteriovenous fistula. In a hybrid operating room, combined treatments can be performed comfortably and safely in a single session of general anesthesia. This treatment option is a viable alternative when other methods are unsuccessful.

MRI features of idiopathic intracranial hypertension are not prognostic of visual and headache outcome.

BACKGROUND: In idiopathic intracranial hypertension (IIH), certain MRI features are promising diagnostic markers, but whether these have prognostic value is currently unknown. METHODS: We included patients from the Vienna-Idiopathic-Intracranial-Hypertension (VIIH) database with IIH according to Friedman criteria and cranial MRI performed at diagnosis. Presence of empty sella (ES), perioptic subarachnoid space distension (POSD) with or without optic nerve tortuosity (ONT), posterior globe flattening (PGF) and transverse sinus stenosis (TSS) was assessed and multivariable regression models regarding visual outcome (persistent visual impairment/visual worsening) and headache outcome (headache improvement/freedom of headache) were fitted. RESULTS: We included 84 IIH patients (88.1% female, mean age 33.5 years, median body mass index 33.7). At baseline, visual impairment was present in 70.2% and headache in 84.5% (54.8% chronic). Persistent visual impairment occurred in 58.3%, visual worsening in 13.1%, headache improvement was achieved in 83.8%, freedom of headache in 26.2%. At least one MRI feature was found in 78.6% and 60.0% had ≥3 features with POSD most frequent (64.3%) followed by TSS (60.0%), ONT (46.4%), ES (44.0%) and PGF (23.8%). In multivariable models, there was no association of any single MRI feature or their number with visual impairment, visual worsening, headache improvement or freedom. Visual impairment at baseline predicted persistent visual impairment (odds ratio 6.3, p<0.001), but not visual worsening. Chronic headache at baseline was significantly associated with lower likelihood of headache freedom (odds ratio 0.48, p=0.013), but not with headache improvement. CONCLUSIONS: MRI features of IIH are neither prognostic of visual nor headache outcome.

Enlarged Vertebral Venous Plexus Alleviated Intracranial Hypertension-Related Symptoms in Patients with Bilateral Transverse Sinus Stenosis.

BACKGROUND: Enlarged vertebral venous plexus (EVVP) was often observed in patients with bilateral transverse sinus stenosis (BTSS). The purpose of this study was to investigate the physiological role of EVVP in BTSS patients. METHODS: Forty-five BTSS patients and 92 normal controls were prospectively recruited from January 2014 to December 2019. The index of transverse sinus stenosis (ITSS) was used for the assessment of BTSS severity. Subjects underwent a standard lumbar puncture to measure the intracranial pressure (ICP). Papilledema and tinnitus were evaluated by using Frisén's grade and questionnaires for Tinnitus Handicap Inventory (THI), respectively. The intensity and impact of headache were assessed by using 10-point Numeric Pain Rating Scale and six-item Headache Impact Test, respectively. RESULTS: The BTSS group had more subjects with intracranial hypertension (IH) and less subjects with normal ICP than normal controls (p < 0.01; p < 0.01). BTSS patients had higher ICP than normal controls (p < 0.01). ICP was significantly lower in BTSS patients with EVVP than in those without EVVP (p < 0.01). No significant difference in ICP was found between normal controls with EVVP and those without EVVP (p = 0.99). A similar incidence of EVVP in BTSS patients and normal controls was found (p = 0.86). BTSS patients with IH exhibited a lower incidence of EVVP than those with normal ICP and overlapping ICP (p < 0.01; p < 0.01). The incidence of EVVP was not correlated with ITSS (p = 0.81). EVVP, rather than ITSS, correlated with ICP (p = 0.01). Furthermore, EVVP alleviated papilledema evaluated by Frisén's grade and tinnitus evaluated by the THI score in BTSS patients (p = 004; p = 0.02). CONCLUSIONS: EVVP in normal controls is a congenital phenomenon that exerts no impact on ICP. However, the presence of EVVP reduces ICP and alleviates IH-related papilledema and tinnitus in BTSS patients.

MRI findings differentiating tonsillar herniation caused by idiopathic intracranial hypertension from Chiari I malformation.

PURPOSE: Some patients with idiopathic intracranial hypertension (IIH) have cerebellar tonsillar herniation ≥ 5 mm mimicking Chiari malformation I (CMI), which can result in misdiagnosis and unjustified treatment. Our purpose was to identify IIH patients with tonsillar herniation ≥ 5 mm (IIHTH) and compare with CMI patients to assess imaging findings that could distinguish the two conditions. METHODS: Ninety-eight patients with IIH, 81 patients with CMI, and 99 controls were retrospectively assessed. Two neuroradiologists blindly reviewed MR images. IIHTH patients were compared with CMI patients and controls regarding the extent of tonsillar herniation (ETH), bilateral transverse sinus stenosis (BTSS), hypophysis-sella ratio (HSR), and bilateral tortuosity of optic nerve (BTON). RESULTS: 13/98 (13.2%) IIH patients had tonsillar herniation ≥ 5 mm (IIHTH) and were significantly younger and had higher BMI compared with CMI patients and controls. ETH was significantly less in the IIHTH than CMI (6.5 ± 2.4 mm vs. 10.9 ± 4.4 mm; p < 0.001). BTSS and HSR < 0.5 were more common in IIHTH than CMI (p < 0.001 and p = 0.003, respectively). No differences were seen between CMI and controls. BTON was significantly more common in IIHTH compared to control (p = 0.01) but not to the CMI (p = 0.36). Sensitivity and specificity to differentiate IIHTH from CMI were 69.2% and 96.1% for BTSS and 69.2% and 75.3% for HSR < 0.5. CONCLUSION: The presence of BTSS and/or HSR < 0.5 in patients with ETH ≥ 5 mm should suggest further evaluation to exclude IIH before considering CMI surgery.

The transcerebral laterocavernous vein, a form of persisting primitive tentorial sinus.

The superficial middle cerebral vein (SMCV) commonly drains in the cavernous sinus. Its different drainage variants include preserved segments of the primitive tentorial sinus. In any of these variants, the terminal venous segment of SMCV passes on the base of the skull. The archived computed tomography angiograms of a 58-year-old female case were documented anatomically. On the left side was found the sinus of the lesser sphenoidal wing converging with the middle meningeal vein to form a venous channel located within the Sylvian fissure at 4 mm laterally to the cavernous sinus and trigeminal cavum. That venous channel was thus termed the 'laterocavernous vein'. It drained posteriorly within the superior petrosal sinus. This aberrant vein could interfere unpleasantly with pterional neurosurgical approaches for the Sylvian fissure, cavernous sinus or trigeminal ganglion.

Why does unilateral pulsatile tinnitus occur in patients with idiopathic intracranial hypertension?

PURPOSE: To investigate the relevant factors of unilateral pulsatile tinnitus (PT) in patients with idiopathic intracranial hypertension (IIH) using CT. METHODS: CT angiography images of IIH patients with unilateral PT (n = 19), without PT (n = 13), and controls (n = 32) were reviewed. The characteristics including transverse sinus stenosis (TSS), venous outflow laterality (VOL), sigmoid sinus wall dehiscence (SSWD), and sigmoid sinus diverticulum (SSD) were quantitatively or/and qualitatively detected. VOL was compared between the symptomatic side of IIH patients with PT and the larger side of IIH patients without PT and the controls. TSS, SSWD, and SSD were compared between the symptomatic side of IIH patients with PT, and both sides of the latter two groups. RESULTS: There was no statistical difference in body mass index or cerebrospinal fluid pressure between IIH patients with and without PT. The prevalence of TSS was significantly higher in IIH patients than that in the controls (p = 0.000), but TSS had no correlation with PT within IIH patients. The prevalence of SSWD successively decreased in IIH patients with PT, without PT, and the controls, with significant differences between each two of three groups (p = 0.000, p' = 0.000, p″ = 0.031). The proportion of VOL and the prevalence of SSD were significantly larger in IIH patients with PT than in the latter groups respectively (pVOL = 0.005, p'VOL = 0.000; pSSD = 0.040, p'SSD = 0.000). All SSDs in IIH patients with PT were accompanied with SSWD. CONCLUSION: The dominant VOL and ipsilateral SSWD with/without SSD may be correlated with the occurrence of unilateral PT in IIH patients.

Synostosis of the lambdoid suture: a spectrum.

PURPOSE: Lambdoid synostosis (LS) is a rare condition, which is either isolated; associated with sagittal synostosis, the "Mercedes-Benz" syndrome (MBS); or with synostosis of the coronal sutures (oxycephalic form). In addition, LS is part of the phenotype of a growing number of genetic diseases. The nosology, pathophysiology, and management are controversial. We decided to review our experience with LS. METHODS: We reviewed retrospectively pediatric cases of LS proved on CT-scanner, isolated or associated with other conditions, followed in our craniofacial center during the last 15 years, regarding clinical presentation, anatomical lesions, syndromic associations, surgical management, and outcome. RESULTS: We reviewed 48 cases: 6 isolated LS, 22 MBS, and 20 oxycephalic. A syndromic context was present in 72% (up to 80% of oxycephalic cases), and faciostenosis was present in 23%, mostly oxycephalic cases (40%). Transverse sinus agenesis was found in 61% of documented patients. A total of 31% of children had a dystocic birth, up to 45% of MBS. Decompressive craniectomy or cranioplasty was needed in a majority of patients, often young infants, while posterior fossa decompression was mostly performed in older children. CONCLUSION: LS is rarely isolated and non syndromic; most cases are found in a wide spectrum of diseases, and LS is often associated with sagittal or coronal synostosis. Genetic evaluation is mandatory for LS; conversely, geneticists may require neurosurgical advice for LS in an increasing number of very rare diseases. The surgical management of LS should be tailored according to clinical presentation, age, and syndromic context.

Dural venous sinus anatomy in children with external hydrocephalus: analysis of a series of 97 patients.

PURPOSE: To evaluate the anatomical variations of dural venous sinuses in children with external hydrocephalus, proposing a radiological grading of progressive anatomic restriction to venous outflow based on brain phase-contrast magnetic resonance venography (PC-MRV); to evaluate the correlation between positional plagiocephaly and dural sinuses patency; and to compare these findings with a control group to ascertain the role of anatomical restriction to venous outflow in the pathophysiology of external hydrocephalus. METHODS: Brain MRI and PC MRV were performed in 97 children (76 males, 21 females) diagnosed with external hydrocephalus at an average age of 8.22 months. Reduction of patency of the dural sinuses was graded as 1 (stenosis), 2 (complete stop) and 3 (complete agenesis) for each transverse/sigmoid sinus and sagittal sinus. Anatomical restriction was graded for each patient from 0 (symmetric anatomy of patent dural sinuses) through 6 (bilateral agenesis of both transverse sinuses). Ventricular and subarachnoid spaces were measured above the intercommissural plane using segmentation software. Positional plagiocephaly (PP) and/or asymmetric tentorial insertion (ATI) was correlated with the presence and grading of venous sinus obstruction. These results were compared with a retrospective control group of 75 patients (35 males, 40 females). RESULTS: Both the rate (84.53% vs 25.33%) and the grading (mean 2.59 vs mean 0.45) of anomalies of dural sinuses were significantly higher in case group than in control group. In the case group, sinus anomalies were asymmetric in 59 cases (right-left ratio 1/1) and symmetric in 22. A significant association was detected between the grading of venous drainage alterations and diagnosis of disease and between the severity of vascular anomalies and the widening of subarachnoid space (SAS). Postural plagiocephaly (39.1% vs 21.3%) and asymmetric tentorial insertion (35.4% vs 17.3%) were significantly more frequent in the case group than in the control group. When sinus anomalies occurred in plagiocephalic children, the obstruction grading was significantly higher on the flattened side (p ≤ 0.001). CONCLUSION: Decreased patency of the dural sinuses and consequent increased venous outflow resistance may play a role in the pathophysiology of external hydrocephalus in the first 3 years of life. In plagiocephalic children, calvarial flattening may impact on the homolateral dural sinus patency, with a possible effect on the anatomy of dural sinuses and venous drainage in the first months of life.

Detection and Differentiation of Dural Arteriovenous Fistulas in the Transverse Sinus/Sigmoid Sinus and Cavernous Sinus Using Carotid Ultrasound: Importance of Evaluation of the Occipital Artery.

OBJECTIVES: Dural arteriovenous fistula (DAVFs) in the transverse sinus (TS)/sigmoid sinus (SS) and cavernous sinus (CS) are observed frequently in the clinic. This study aimed to detect DAVFs with ultrasound and compare carotid ultrasound findings between these conditions. METHODS: We retrospectively reviewed 26 patients with either a TS/SS DAVF or a CS DAVF who were admitted to our hospital for evaluation of DAVFs from 2014 to 2018. The shunt site decision was made by neuroendovascular experts, whereas carotid ultrasound examinations were performed by ultrasound specialists. The flow velocity of the ipsilateral external carotid artery was reviewed in all 26 patients, whereas that of the occipital artery (OA) was examined in 20 patients. Blood flow velocities were compared between the TS/SS DAVF and CS DAVF groups. RESULTS: The study included 18 patients with a TS/SS DAVF (11 women and 7 men; mean age ± SD, 65.3 ± 18.6 years) and 8 patients with a CS DAVF (7 women and 1 man; mean age, 70.4 ± 9.3 years). Evaluations of feeder arteries on cerebral angiography showed that all patients had dural branches from the internal carotid and middle meningeal arteries as feeders of CS DAVFs, whereas the OA was the major feeder source of all TS/SS DAVF cases. The end-diastolic velocity (EDV) of the external carotid artery was significantly higher in patients with a TS/SS DAVF compared with those with a CS DAVF (P = .004). The EDV of the OA was significantly elevated in TS/SS DAVF cases compared with CS DAVF cases (P < .001). CONCLUSIONS: Duplex ultrasound parameters are significantly different between patients with TS/SS and CS DAVFs. An increased EDV of the OA can predict the presence of a TS/SS DAVF.

Associations Between Doppler Internal Jugular Vein Blood Flow and Transverse Sinus Stasis Detected by Magnetic Resonance Imaging.

OBJECTIVES: This study aimed to compare the estimated internal jugular vein (IJV) volume flow with Doppler ultrasound in patients with slow flow in the transverse sinuses and normal transverse sinuses on brain magnetic resonance imaging (MRI). METHODS: Eighty patients between the ages of 18 and 80 years who did not have any signs of sinus vein thrombosis on brain MRI were included. On MRI, cases with hyperintensity due to a signal void loss in the transverse sinuses in coronal fluid attenuation inversion recovery sequences were included in the slow-flow group. The presence of sinus thrombosis was excluded with other MRI pulse sequences and clinical findings. The participants were divided into 2 groups as having normal and slow flow according to MRI findings. Then bilateral IJV volume flow measurements were made by Doppler ultrasound. Bilateral volume flow was estimated by time-averaged blood flow velocities sampled in the center of the IJV, and IJV cross-sectional areas were measured. We defined the dominant IJV as the one having the higher estimated volume flow of the 2 sides. RESULTS: Total estimated IJV blood flow was lower (P < .001) in patients with slow flow on MRI (546 mL/min) compared to those without (768 mL/min). A similar finding was seen for the nondominant IJV. In a receiver operating characteristic analysis, the cutoff value for the total estimated IJV volume flow was determined to be 590 mL/min, and the cutoff value for nondominant estimated IJV volume flow was determined to be 202 mL/min to distinguish between the groups. CONCLUSIONS: Low estimated volume blood flow in the IJV is associated with MRI evidence of stasis in the ipsilateral transverse sinus.