Cerebral Sinus Hemodynamics in Adults Revealed by 4D Flow MRI.

BACKGROUND: The hemodynamics of the cerebral sinuses play a vital role in understanding blood flow-related diseases, yet the hemodynamics of the cerebral sinuses in normal adults remains an unresolved issue. PURPOSE: To evaluate hemodynamics in the cerebral sinus of adults using 4-dimensional flow MRI (4D Flow MRI). STUDY TYPE: Cross-sectional. POPULATION: Ninety-nine healthy volunteers (mean age, 42.88 ± 13.16 years old; females/males, 55/44). FIELD STRENGTH/SEQUENCE: 3 T/4D Flow MRI. ASSESSMENT: The blood flow velocity, average blood flow rate (Q), and vortexes at the superior sagittal sinus (SSS), straight sinus (STS), transverse sinus, sigmoid sinus, and jugular bulb of each volunteer were evaluated by two independent neuroradiologists. The relationship between the total cerebral Q and sex and age was also assessed. Twelve volunteers underwent two scans within a month. STATISTICAL TESTS: The intraclass correlation coefficient (ICC) evaluated the inter-observer agreement. Blood flow parameters among volunteers were compared by the independent-sample t-test or Mann-Whitney U test. The multiple linear regression equation was used to evaluate the relationship between total cerebral Q and age and sex. P < 0.05 indicated statistical significance. RESULTS: The test-retest and interobserver reliability of average velocity and Q were moderate to high (ICC: 0.54-0.99). Cerebral sinus velocity varied by segment and cardiac cycle. The SSS's velocity and Q increased downstream and Q near torcular herophili was 3.5 times that through the STS. The total cerebral Q decreased by 0.06 mL/s per year (ß = -0.06 ± 0.013) and was sex-independent within the group. Vortexes were found in 12.12%, 8.9%, and 59.8% of torcular herophili, transverse-sigmoid junction, and jugular bulb, respectively, and were related to higher upstream flow. DATA CONCLUSION: Cerebral sinuses could be measured visually and quantitatively in vivo by 4D Flow MRI, providing a basis for future research on pulsating tinnitus, multiple sclerosis, and other related diseases. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 1.

Comment on "Route patterns of the collateral venous pathway in patients with tumors invading the superior sagittal sinus: an angiographic study and clinical applications".

This commentary critiques the study "Route patterns of the collateral venous pathway in patients with tumors invading the superior sagittal sinus" by Pawit Jirawisan et al., highlighting its limitations in discussing parafalcine venous collaterals, reliance on invasive imaging modalities, and lack of structured assessments. It suggests improvements by incorporating alternative imaging techniques, acknowledging crucial venous structures, and providing grading systems for surgical decision-making.

Route patterns of the collateral venous pathway in patients with tumors invading the superior sagittal sinus: an angiographic study and clinical applications.

Chronic occlusion of the superior sagittal sinus (SSS) by tumors in the midsagittal region causes the collateral venous pathway (CVP). Understanding common patterns of CVP is helpful in reducing surgical complications. This study aimed to investigate the CVP found in patients with SSS-invading tumors, and to provide information on the prevention of operative venous complications. From January 2015 to December 2022, this retrospective study collected patients with tumors that invaded the SSS and underwent digital subtraction angiography of intracranial vessels. Data collected included sex, age, tumor pathology, tumor location along the SSS, tumor side, degree of obstruction of the SSS, types and route patterns of the CVP, and the distance between the tumor and the diploic vein (DV). Twenty patients (6 males, 14 females) were recruited. The prevalence of CVP types was 90% for DV, 35% for end-to-end anastomosis of superficial cortical vein, 15% for meningeal vein, and 20% for other types of CVP. The pteriofrontoparietal and occipitoparietal diploic routes were found on the cerebral hemisphere contralateral to the tumor significantly more than in the cerebral hemisphere ipsilateral to the tumor. Of all patients with presence of collateral DV, 61% had a very close (less than 1 cm) distance between the nearest DV and tumor attachment in the SSS. DV in the cerebral hemisphere contralateral to the tumor was the most common type of CVP found in patients with tumor-induced SSS obstruction. Most of the collateral DV was located very close to the SSS tumor attachment. Neurosurgeons should realize these findings when planning a craniotomy.

Clinical and radiological features of parasagittal dural arteriovenous fistulas: a report of 8 cases from a single institution.

OBJECTIVE: Dural arteriovenous fistulas (dAVFs) of the superior sagittal sinus (SSS) are uncommon and represent 5%-12% of all intracranial dAVFs. SSS dAVFs can be divided into two main subtypes. The first type involves direct arterialization of the SSS, whereas the second type consists of a parasagittal arteriovenous shunt draining into a cortical vein directly lateral to the SSS and has retrograde cortical venous drainage with only secondary involvement of the SSS. Descriptions of the latter type of SSS dAVF are limited. As such, the authors present a consecutive case series of parasagittal SSS dAVFs from their institution. They detail clinical presentation, treatment strategies, and clinical and radiographic outcomes. METHODS: The authors retrospectively reviewed a prospectively collected database of dAVFs that were treated between 2017 and 2023. All dAVFs characterized by an arterialized parasagittal vein directly lateral to the SSS were included in this study. Baseline demographic, clinical, radiological, treatment, and outcome-specific variables of interest were abstracted. RESULTS: One hundred fifty-four dAVFs were seen at the authors' institution over the 6-year period of interest. Eight (5.2%) were parasagittal dAVFs. At initial diagnostic imaging, 7 were Cognard grade III and 1 was grade IV. All patients initially underwent embolization of their dAVF. Three patients did not have complete obliteration of their dAVF after the first embolization. One patient underwent further treatment with repeat embolization, and 1 underwent microsurgical disconnection-both resulted in complete occlusion of the dAVF. Seven dAVFs were obliterated at final follow-up and 1 remained patent as the patient refused further treatment despite angiographic progression of dAVF. All symptomatic patients had resolution of their symptoms, and the average length of follow-up was 16.8 months. CONCLUSIONS: Treatment of parasagittal dAVFs consists of occluding the proximal portion of the parasagittal arterialized draining vein. Endovascular therapy with liquid embolic agents is usually the first line of treatment. Surgical ligation is a valid option if the fistula cannot be successfully obliterated with embolization. Symptoms related to the SSS dAVF resolve after their obliteration.

Direct superior sagittal sinus puncture via a surgical burr hole for curative embolization of the complex transverse-sigmoid sinus dural arteriovenous fistula: How I do it.

BACKGROUND: Transvenous embolization of high-grade dural arteriovenous fistulas (dAVFs) is challenging particularly when the direct sinus access is favorable due to the complex venous anatomy which prohibits endovascular access via the transfemoral approach. METHOD: The procedure was conducted in the hybrid operating suite, where a burr hole was performed, followed by direct catheterization of the superior sagittal sinus. Coil embolization was then executed to achieve complete obliteration of the fistula. CONCLUSION: The direct puncture of the superior sagittal sinus is a safe and effective method for treating complex dAVFs. This approach grants access to the fistula channel which facilitates curative embolization.

An epidural brain abscess and thrombus in the superior sagittal sinus in a 12 year-old with sinusitis.

BACKGROUND: Upper respiratory infections can be complicated by acute bacterial sinusitis in pediatric patients, and usually resolve with antibiotic therapy (DeMuri and Wald, 2011). However, intracranial complications such as: epidural abscess, meningitis and more rarely cerebral sinus venous thrombosis (CSVT) can occur (Germiller et al., 2006). We report an unusual case of sinusitis complicated by an epidural abscess and later a CSVT in a young previously healthy patient. CASE DESCRIPTION: A 12-year-old female presented to the emergency department with a 9-day history of headaches and a 3-day history of fevers, rigors, nasal congestion and nonproductive cough. She later tested positive for Covid-19. CT and MRI showed extensive paranasal sinus disease and a right frontal epidural collection. MRV showed no sinovenous thrombosis. Washout and burr hole drainage alongside endoscopic sinus surgery was completed and post-op imaging showed evacuation of the epidural abscess with a small residual collection. Six days after the procedure, she experienced worsening headaches and MRV showed a nonocclusive thrombus in the superior sagittal sinus, which was treated with anticoagulation therapy. Upon follow-up, the patient showed improvement of the sinusitis, abscess and thrombus. CONCLUSION: This specific case encourages clinicians to be aware of complications, though rare, and to diagnose and treat sinusitis cases quickly. It is also important to be aware of any risk factors for thrombus formation, including an inflammatory and hypercoagulable state. In the patient's case, it was perceived that the CSVT was provoked due to the patient's Covid-19 infection, abscess, and sinus disease.

Parasagittal Meningiomas: Prognostic Factors for Recurrence.

The term parasagittal meningioma applies to those tumors that are associated with the superior sagittal sinus (SSS), originating from the dura mater in close relation to the parasagittal wall or angle, with no intervening brain tissue, possibly extending to the dura of the convexity and/or falx cerebri.(Cushing et al., Meningiomas: their classification, regional behaviour, life history, and surgeical and results. Hafner, 1938) They make up about 20-30% of all meningiomas. There is a vast literature correlating the Simpson grade of resection with later recurrence. Frequent involvement of the superior sagittal sinus (SSS) by these tumors means that the optimal treatment recommended in the literature-complete resection, including of the dural base-is one of the most challenging.

Utility of MRI in surgical planning for parasagittal meningiomas.

BACKGROUND: Surgical resection is the standard treatment for parasagittal meningioma (PSM), but complete resection may be challenging due to superior sagittal sinus (SSS) involvement. The SSS may be partially or completely obstructed, and collateral veins are commonly present. Thus, knowing the status of the SSS in PSM cases prior to treatment is essential to a successful outcome. MRI is utilized prior to surgery in order to determine SSS status and to check for presence of collateral veins. The objective of this study is to evaluate the reliability of MRI in predicting both SSS involvement and presence of collateral veins in subsequent comparison to actual intra-operative findings, and to report on complications and outcomes. METHODS: 27 patients were retrospectively analyzed for this study. A blinded radiologist reviewed all pre-operative images, noting SSS status and collateral vein presence. Intraoperative findings were obtained from hospital records to similarly categorize SSS status and collateral vein presence. RESULTS: Sensitivity of the MRI to SSS status was found to be 100% and specificity was 93%. However, sensitivity and specificity of MRI to collateral vein presence was only 40% and 78.6%, respectively. Complications were experienced by 22% of patients, the majority neurologic in nature. CONCLUSION: MRI accurately predicted SSS occlusion status, but was less consistent in identification of collateral veins. These findings suggest MRI should be used with caution prior to PSM resection surgery particularly with regards to the presence of collateral veins which may complicate resection.

Predictors of recurrence after surgical resection of parafalcine and parasagittal meningiomas.

PURPOSE: Owing to their vicinity near the superior sagittal sinus, parasagittal and parafalcine meningiomas are challenging tumors to surgically resect. In this study, we investigate key factors that portend increased risk of recurrence after surgery. METHODS: This is a retrospective study of patients who underwent resection of parasagittal and parafalcine meningiomas at our institution between 2012 and 2018. Relevant clinical, radiographic, and histopathological variables were selected for analysis as predictors of tumor recurrence. RESULTS: A total of 110 consecutive subjects (mean age: 59.4 ± 15.2 years, 67.3% female) with 74 parasagittal and 36 parafalcine meningiomas (92 WHO grade 1, 18 WHO grade 2/3), are included in the study. A total of 37 patients (33.6%) exhibited recurrence with median follow-up of 42 months (IQR: 10-71). In the overall cohort, parasagittal meningiomas exhibited shorter progression-free survival compared to parafalcine meningiomas (Kaplan-Meier log-rank p = 0.045). On univariate analysis, predictors of recurrence include WHO grade 2/3 vs. grade 1 tumors (p < 0.001), higher Ki-67 indices (p < 0.001), partial (p = 0.04) or complete sinus invasion (p < 0.001), and subtotal resection (p < 0.001). Multivariable Cox regression analysis revealed high-grade meningiomas (HR: 3.62, 95% CI: 1.60-8.22; p = 0.002), complete sinus invasion (HR: 3.00, 95% CI: 1.16-7.79; p = 0.024), and subtotal resection (HR: 3.10, 95% CI: 1.38-6.96; p = 0.006) as independent factors that portend shorter time to recurrence. CONCLUSION: This study identifies several pertinent factors that confer increased risk of recurrence after resection of parasagittal and parafalcine meningiomas, which can be used to devise appropriate surgical strategy to achieve improved patient outcomes.

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.

Repair of the superior sagittal sinus following penetrating intracranial injury caused by nail gun accident: case report and technical note.

We report a 45-year-old man who suffered a penetrating nail gun injury resulting in damage to the lateral edge of the superior sagittal sinus. The injury was successfully treated via a parasagittal craniotomy that enabled removal of the nail under direct vision, allowing for rapid suturing of the sagittal sinus. Two neurosurgeons worked together; one carefully withdrew the tip of the nail back into the sinus itself while the second rapidly sutured the hole in the inner superior sagittal sinus leaflet. Postoperatively, the patient made a rapid recovery without neurological deficit.

Hypofractionated stereotactic radiosurgery for dural arteriovenous fistula in the superior sagittal sinus: case report and review of the literature.

Stereotactic radiosurgery (SRS) for dural arteriovenous fistula (dAVF) in the superior sagittal sinus (SSS) is not an established treatment because of relatively poor efficacy and a latency period for treatment effects. Hypofractionated SRS for these lesions has not yet been reported. A 65-year-old man presented with intermittent paraparesis. Brain magnetic resonance imaging (MRI) revealed acute infarction in the premotor and motor cortex of both frontal convexities. Cerebral angiography demonstrated extensive dAVF in the middle and posterior third SSS, associated with an occlusion in the middle third. Transfemoral arterial Onyx embolization was performed through the right middle meningeal arteries, and cerebral venous reflux (CVR) disappeared from the middle third of the SSS. However, the remnant dAVF in the posterior third of the SSS and CVR in the posterior parietal and occipital lobes remained. Novalis SRS was performed on remnant the dAVF with 35 Gy in 5 fractions. Seven months after Novalis SRS, symptoms improved and cortical engorged vessel gradually disappeared on brain MRI. The patient recovered completely at 22 months post-radiosurgery. SRS for dAVF in the SSS could provide an alternative treatment option. Hypofractionated SRS showed a good result in our case.

Fulminant Extra- And Intracranial Arteriovenous Thrombosis And Non-aneurysmal Subarachnoid Hemorrhage Following COVID-19 Infection.

PURPOSE: Coronavirus disease of 2019 (COVID-19) is associated with increased risk of stroke and intracranial hemorrhage. This first report of fulminant panvascular arteriovenous thrombosis with subarachnoid hemorrhage (SAH) in a post-COVID-19 infection is attributed to extensive arteriovenous inflammation leading to arterial rupture following vasculitis. CASE REPORT: We report a rare case of extensive extra- and intra-cranial cerebral arteriovenous thrombosis following COVID-19 infection, presenting as fatal non-aneurysmal subarachnoid hemorrhage. The clinical course, biochemical and radiological evaluation is discussed. The other possible etiological differentials which were analysed and ruled out during case management are also detailed. CONCLUSION: A high degree of suspicion for COVID-19 induced coagulopathy leading to extensive non- aneurysmal, non-hemispheric SAH and malignant intracranial hypertension should be entertained. Our experience and previous reports on non-aneurysmal SAH in such patients show a poor prognosis.

Histomorphometry of mast cells in the convexity of human intracranial dura mater.

Mast cells, known as pro-inflammatory effector cells, are immunocytes present in the meninges and may be involved in the pathophysiology of migraine. This study aims to evaluate the histomorphometric parameters of mast cells located in the convexity of the human intracranial dura mater. For this, samples of intracranial dura mater from eight human fresh cadavers were collected between 8- and 24-h post-mortem. The whole samples were fixed and, subsequently, two fragments of 1.5 cm² each were cut from four different areas of the dura mater convexity, containing a segment of the middle meningeal artery, totaling 64 fragments. After histological processing, the fragments were submitted to microtomy (5 and 10 µm), stained with toluidine blue (0.1%), or immunohistochemically labeled for tryptase, and analyzed using optical microscopy. The following histomorphometric parameters were evaluated: distance from mast cells to vessels, the density of mast cells, and percentage of mast cells with degranulation. Histomorphometric analyzes showed a higher density of mast cells in the vicinity of blood vessels (arterial and venous), with distances around 0-150 µm. A greater number of mast cells was detected near venous vessels in the periosteal layer (17.0 ± 10.1 cells/mm²) than in the meningeal layer (14.1 ± 7.0 cells/mm²) (p < 0.05). Mast cells from the region close to the superior sagittal sinus were found in greater quantity close to the venous vessels (16.7 ± 10.1 cells/mm²) than to the arterial vessels (11.2 ± 7.5 cells/mm²) (p < 0.05). In short, in the convexity of the human intracranial dura mater, mast cells are located close to blood vessels, with a greater number of cells next to the venous vessels of the periosteal layer and in the proximal region of the superior sagittal sinus.

How I do it: the surgical resection of a middle third parasagittal meningioma with venous preservation strategy.

BACKGROUND: The surgical resection of the middle third parasagittal meningioma (PSM) is difficult, where the challenge is to systematically protect the eloquent parenchyma and collateral venous drainage. METHOD: We report a case of PSM that eroded the skull, wholly occluded the superior sagittal sinus at the middle third segment, underwent radical resection with evaluation and preservation of the collateral venous drainage by preoperative venography, and intraoperative indocyanine green videoangiography (ICGVA) that aimed to avoid postoperative complications. CONCLUSION: This case demonstrates the importance of venous preservation strategy and the value of ICGVA in the intraoperative assessment of collateral venous drainage function.

A simple and successful treatment for rupture and defect of the posterior third superior sagittal sinus caused by open depressed skull fracture: A case report.

It is extremely dangerous to treat the posterior third of the superior sagittal sinus (PTSSS) surgically, since it is usually not completely ligated. In this report, the authors described the case of a 27-year-old man with a ruptured and defective PTSSS caused by an open depressed skull fracture, which was treated by ligation of the PTSSS and the patient achieved a positive recovery. The patient's occiput was hit by a height-limiting rod and was in a mild coma. A CT scan showed an open depressed skull fracture overlying the PTSSS and a diffuse brain swelling. He underwent emergency surgery. When the skull fragments were removed, a 4 cm segment of the superior sagittal sinus (SSS) and the adjacent dura mater were removed together with bone fragments. Haemorrhage occurred and blood pressure dropped. We completed the operation by ligating the severed ends of the fractured sagittal sinus. One month after the operation, apart from visual field defects, he recovered well. In our opinion, in primary hospitals, when patients with severely injured PTSSS cannot sustain a long-time and complicated operation, e.g., the bypass using venous graft, and face life-threatening conditions, ligation of the PTSSS is another option, which may unexpectedly achieve good results.

[Surgical treatment of large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading].

OBJECTIVE: To investigate the surgical strategy for large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading. METHODS: The clinical data of 16 patients with large and giant recurrent meningioma in the middle and posterior third part of the superior sagittal sinus with extracranial invasion who underwent surgery in the Department of Neurosurgery of Peking University Third Hospital from May 2019 to May 2022 were retrospectively analyzed. All the patients underwent brain-enhanced magnetic resonance imaging (MRI), magnetic resonance venography (MRV), computed tomography angiography (CTA) and three-dimensional skull computed tomography (CT) before, to evaluate the extent of tumor invasion, the edema of brain tissue, the degree of skull damage, the blood supply of the tumor, and the degree of compression of the superior sagittal sinus, etc, and to formulate an individualized surgical plan. The neurological function of the patients was evaluated 1 week, 1 month, and 3 months after the operation, and the tumor condition was evaluated by brain-enhanced MRI 3 months, 6 months, and 1 year after the operation. RESULTS: The tumors in the 16 patients were all located in the middle and posterior 1/3 part of the superior sagittal sinus and invaded extracranially. Among them, 8 cases were operated for the second time, 6 cases for the third time, and 2 cases for the fourth time; In the last operation, the bone flap was used to repair the skull in 4 cases, and the titanium mesh was used in 12 cases; Tumor arterials of 3 cases were embolized under digital subtraction angiography (DSA). Tumors of 10 cases were resected at Simpson grade Ⅰ, and 6 cases at Simpson grade Ⅱ; 2 cases underwent decompressive craniectomy during operation, and 14 cases underwent cranioplasty at the same time; scalp incisions of 14 cases were directly sutured, and flap transposition was used in 14 cases. When evaluating nerve function after operation, the limb muscle strength was improved compared with that before operation, and the Karnofsky performance scale (KPS) score reached 100 points 3 months after operation. During the follow-up, 1 patient's tumor recurred after 1 year and received Gamma Knife treatment, and the rest of the patients had no recurrence during the follow-up period. CONCLUSION: Surgical treatment is the first choice for large and giant recurrent meningiomas near the middle and posterior third part of the superior sagittal sinus with extracranial invading. It is a safe and effective surgical method to take individualized surgical plan after detailed preoperative assessment of cerebral edema, tumor blood supply, venous sinus compression, and scalp invasion.

Measurements of venous oxygen saturation in the superior sagittal sinus using conventional 3D multiple gradient-echo MRI: Effects of flow velocity and acceleration.

PURPOSE: This work investigates the effects of flow acceleration in the superior sagittal sinus on slice-dependent variations in venous oxygen saturation (SvO2 ) estimations using susceptibility-based MR oximetry. METHODS: Three-dimensional multiple gradient-echo images, with first-order flow compensation along the anterior-posterior readout direction for the first echo, were acquired twice from 15 healthy volunteers. For all slices, phases within the superior sagittal sinus were fitted using linear regression across four TEs to obtain the Pearson's correlation coefficients (PCCs), the largest of which corresponded to minimum acceleration influence. SvO2 derived from odd echoes on this slice was used to assess interscan difference, and compared with the central 15th slice for slice-dependent difference, both using Bland-Altman analysis. Within-scan interslice SvO2 consistency was examined versus PCC. Multislice-averaged SvO2 values were then computed from slices with PCCs above a certain threshold. RESULTS: Slice-dependent difference in SvO2 varied from -16.2% to 21.5% at two SDs, in agreement with a recent report, and about twice larger than interscan differences for the automatically selected slice (-7.5% to 10.3%) and for the central 15th slice (-8.0% to 8.8%). For slices with PCCs higher than -0.98, interslice SvO2 deviations were all found to be less than 5.0%. Multislice-averaged SvO2 with PCCs higher than -0.98 further reduced interscan difference to -4.7% to 8.2%. CONCLUSION: Slice-dependent variations in SvO2 may partly be explained by the effects of flow acceleration. Our method may enable conventional 3D multiple gradient echo to be used for SvO2 estimations in the presence of pulsatile flow.

Robust arterial input function surrogate measurement from the superior sagittal sinus complex signal for fast dynamic contrast-enhanced MRI in the brain.

PURPOSE: Accurately estimating the arterial input function for dynamic contrast-enhanced MRI is challenging. An arterial input function is typically determined from signal magnitude changes related to a contrast agent, often leading to underestimation of peak concentrations. Alternatively, signal phase recovers the accurate peak concentration for straight vessels but suffers from high noise. A recent method proposed to fit the signal in the complex plane by combining the advantages of the previous 2 methods. The purpose of this work is to refine this complex-based method to determine the venous output function (VOF), an arterial input function surrogate, from the superior sagittal sinus. METHODS: We propose a state-of-the-art complex-based method that includes direct compensation for blood inflow and signal phase correction accounting for the curvature of the superior sagittal sinus, generally assumed collinear with B0 . We compared the magnitude-, phase-, and complex-based VOF determination methods against various simulated biases as well as for 29 brain metastases patients. RESULTS: Angulation of the superior sagittal sinus relative to B0 varied widely within patients, and its effect on the signal phase caused an underestimation of peak concentrations of up to 65%. Correction significantly increased the VOF peak concentration for the phase- and complex-based VOFs in the cohort. The phase-based method recovered accurate peak concentrations but lacked precision in the tail of the VOF. Our complex-based VOF completely recovered the effect of inflow and resulted in a high-peak concentration with limited noise. CONCLUSION: The new complex-based method resulted in high-quality VOF robust against superior sagittal sinus curvature and variations in patient positioning.

Ventriculo-femoro-caval shunt: a salvage surgery.

Ventriculo-femoral vein shunts have been described in few case reports as an alternative for treating complex cases of hydrocephalus in which other accesses are discarded. To our best knowledge, only 6 cases have been reported in the literature to date. We present a case of a 2-year-old female patient with hydrocephalus secondary to neonatal sepsis and meningitis. Patient was operated with various types of shunting procedures, such as ventriculo-peritoneal (V-P) shunt, ventriculo-atrial (V-A) shunt, ventriculo-pleural (V-PL) shunt, ventriculo-vesical shunt, ventriculo-superior sagittal sinus (V-SSS) shunt, and ventriculo-caval (V-C) shunt. All previous procedures were unsuccessful in treating the hydrocephalus. Finally, right ventriculo-femoro-caval shunt procedure was performed. Distal catheter was inserted into the right femoral vein and passed toward inferior vena cava under fluoroscopy guidance. The early postoperative period was uneventful. Late postoperative complications consisting of few periods of shunt dysfunction and distal obstruction were managed as an outpatient with injection for diluted heparin in the shunt valve, resulting in recovery of the shunt function. This was the management until the age of 4 when the femoral vein shunt was removed and right ventriculo-pleural shunt was placed. The patient tolerated this surgery and long-term follow-up showed good neurological status without episodes of shunt dysfunction.