Radiol Oncol 2022; 56(3): 303-310. doi: 10.2478/raon-2022-0029 303 research article Early isolated subarachnoid hemorrhage versus hemorrhagic infarction in cerebral venous thrombosis Jan Kobal1, Ksenija Cankar2, Kristijan Ivanusic3, Borna Vudrag4, Katarina Surlan Popovic3,5 1 Department of Neurology, University Medical Centre Ljubljana, Ljubljana, Slovenia 2 Institute of Physiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia 3 Department of Neuroradiology, University Medical Centre Ljubljana, Ljubljana, Slovenia 4 Service of Neurology, Izola General Hospital, Izola, Slovenia 5 Department of Radiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia Radiol Oncol 2022; 56(3): 303-310. Received 25 February 2022 Accepted 14 June 2022 Correspondence to: Jan Kobal, M.D., Department of Neurology, University Medical Centre Ljubljana, Zaloška 2, SI-1000 Ljubljana, Slovenia. E-mail: jan.kobal@gmail.com Disclosure: No potential conflicts of interest were disclosed. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Background. Cerebral venous thrombosis (CVT) is a rare cerebral vascular disease, the presentation of which is highly variable clinically and radiologically. A recent study demonstrated that isolated subarachnoid hemorrhage (iSAH) in CVT is not as rare as thought previously and may have a good prognostic significance. Hemorrhagic venous infarction, however, is an indicator of an unfavorable outcome. We therefore hypothesized that patients who initially suffered iSAH would have a better clinical outcome than those who suffered hemorrhagic cerebral infarction. Patients and methods. We selected patients hospitalized due to CVT, who presented either with isolated SAH or cerebral hemorrhagic infarction at admission or during the following 24 hours: 23 (10 men) aged 22–73 years. The data were extracted from hospital admission records, our computer data system, and the hospital radiological database. Results. The iSAH group consisted of 8 (6 men) aged 49.3 ± 16.2 and the hemorrhagic infarction group included 15 (4 men) aged 47.9 ± 16.8. Despite having a significantly greater number of thrombosed venous sinuses/deep veins (Mann-Whitney Rank Sum Test, p = 0.002), the isolated SAH group had a significantly better outcome on its modified Rankin Score (mRs) than the hemorrhagic infarction group (Mann-Whitney Rank Sum Test, p = 0.026). Additional vari- ables of significant impact were edema formation (p = 0.004) and sulcal obliteration (p = 0.014). Conclusions. The patients who suffer iSAH initially had a significantly better outcome prognosis than the hemorrhagic infarction patients, despite the greater number of thrombosed sinuses/veins in the iSAH group. A possible explanation might include patent superficial cerebral communicating veins. Key words; cerebral venous thrombosis; subarachnoid hemorrhage; hemorrhagic brain infarction; superficial com- municating veins Introduction Cerebral venous thrombosis (CVT) is a rare cerebral vascular disease that represents a minor proportion of all strokes. A recent Dutch multicentric study re- vealed an incidence of 1.3 per 100,000 adults.1 The presentation of CVT is highly variable, not only clinically but also radiologically.2,3 Improvement in imaging techniques has enabled the identification of less obvious CVT cases; the incidence of CVT is increasing.4 Symptoms and signs depend not only on the location but also on the rate of thrombus pro- gression. Involvement of multiple venous sinuses/ veins may cause a wide variety of symptoms, e.g., headache, seizures, focal deficits, and disturbed consciousness, which may even proceed to coma. Radiol Oncol 2022; 56(3): 303-310. Kobal J et al. / Isolated SAH and hemorrhagic infarction304 The wide spectrum of possible radiological pres- entations ranges from brain edema accompanying venous sinus or cortical vein thrombosis to venous infarction, which may be hemorrhagic and accom- panied by SAH and hematocephalus. Isolated SAH (iSAH) may also appear without venous infarc- tion.5,6 Superficial CVT manifestations such as cor- tical or perimesencephalic SAH secondary to cer- ebral venous thrombosis are considered to be very rare.7,8 A recent study, however, demonstrated that 33 CVT patients in a series of 332 presented with SAH and 22 of those with iSAH mostly accompa- nied by thrombosis in cortical veins, lateral sinus, and/or superior sagittal sinus. The outcome was favorable in all but one patient, who died of pul- monary embolism.9 In contrast, a prospective and retrospective Pakistani and Middle East study re- vealed hemorrhagic infarction to be the most signif- icant feature of a long-term unfavorable outcome.10 Another study from Pakistan revealed hemorrhagic brain infarction to be usually associated with mul- tiple venous sinus/vein occlusions. Superior sagit- tal, transverse, and sigmoid sinuses were most of- ten occluded, as well as the internal jugular vein, straight sinus, cortical and deep cerebral veins.11 Hemorrhagic infarction as a factor in an unfavora- ble outcome, therefore, seems to be associated with multiple venous sinus, superficial and deep vein occlusions. Nevertheless, unsolved dilemmas about hemodynamics and the therapeutic approach still exist.12,13 Multiple cerebral sinuses/veins may be oc- cluded in hemorrhagic infarction patients as also iSAH patients. An interesting recent hypothesis suggests that isolated SAH in CVT may be a conse- quence of blood leakage from fragile dilated bridg- ing cortical veins, which have no valves or muscu- lar layer.7,14,15 Bridging cortical veins are abundant near the tentorial and dural venous sinuses.16,17 According to a previous experimental study, cortical SAH and perimesencephalic SAH in CVT patients indicates an increased blood flow in the superficial communicating veins from which the bridging veins originate.18 We, therefore, propose that early iSAH, either cortical or perimesencephal, indicates persistent collateral venous flow and is a good prognostic sign in CVT patients. To find out what features may influence the outcome in CVT patients, we decided to analyze retrospectively files of CVT patients hospitalized at our clinical ward for vascular neurology in the past 11 years. We hypothesized that patients with a better clinical outcome might have retained patent superficial communicating veins and consequently suffer iSAH rather than hemorrhagic infarct. They would therefore be spared from the mass effect of a hemorrhagic infarct. We consequently decided to examine by hand clinical and radiological details in files of our CVT patients who presented with iSAH or hemorrhagic infarction within the first 24 hours after admission; we sought to identify radiological features that might explain their clinical outcome. Patients and methods Patients and methods Sixty-three CVT patients were admitted to the Department of Neurology, UMC Ljubljana, be- tween January 1, 2008, and December 31, 2018.19 The patients were diagnosed and treated in our hospital, and only those in whom CVT was prov- en clinically and radiologically were identified as such. Among those, we chose patients who pre- sented either with iSAH or cerebral hemorrhagic infarction at admission or within the next 24 hours. Twenty-three patients from our inventory were enrolled in our retrospective observational study. Clinical and radiological data were analyzed. The patients were 13 women and 10 men aged 22–73 years. The data were reviewed by an experi- enced neurologist working in the vascular neurol- ogy ward of the Department of Neurology, UMC Ljubljana. At admission, all the patients presented with either hemorrhagic venous infarction or iSAH due to CVT. Patients presenting with other intrac- ranial and/or systemic pathology that can cause hemorrhagic lesions and/or isolated SAH (e.g., ruptured aneurysms, arteriovenous malforma- tion, amyloidosis, PRES syndrome) were not in- cluded.20,21 The data were extracted from hospital admission records, our computer data system, and the AGFA radiological database, all in accord with the Helsinki Declaration. Reports and scans were de-identified and coded before evaluation. The study was approved by the Slovenian National Medical Ethics Committee (163/02/09). CVT was diagnosed by clinical examination, fol- lowed by brain CT, CT venography (CTV), brain MR and MR venography (MRV), whenever nec- essary, and laboratory findings, (e.g., d-dimer, C-reactive protein, coagulation screening, along with a complete blood count and biochemical pro- file). The following sinuses/deep veins were found to be obstructed in the iSAH group: the transverse sinus in 8 (bilaterally in 4 patients), the sigmoid si- nus in 7 (bilaterally in 1), the superior sagittal sinus in 5, the jugular vein bulb in 5, the confluence of sinuses in 3, the straight sinus in 2, and the vein Radiol Oncol 2022; 56(3): 303-310. Kobal J et al. / Isolated SAH and hemorrhagic infarction 305 of Galen in 1 patient. In the hemorrhagic infarc- tion group, we found the superior sagittal sinus obstructed in 8 patients, the straight and sigmoid sinus in 6, the jugular vein bulb in 3, the internal cerebral vein in 2 (in 1 bilaterally), the basilar vein in 1 (bilaterally), the straight sinus in 1, the pet- rosal sinus in 1, and the vein of Galen in 1 patient. We also searched for environmental precipitating factors for CVT (e.g., trauma) as well as known intrinsic and acquired predisposing/precipitating factors (e.g., infections, contraceptive abuse, malig- nant disease, hematologic conditions, noninfective inflammatory disease, intracranial hypotension, acquired and genetic prothrombotic states).21 All the patients received anticoagulant treatment im- mediately after the diagnostic procedures were completed. They were started on low molecular heparin in a therapeutic dose and switched to war- farin before discharge. Average discharge time was about 3 weeks from admission, and a control clini- cal examination was typically performed 3–4 but not more than 6 months after discharge. Radiological analysis The type/location of venous infarct, intracerebral hemorrhage, and/or subarachnoid hemorrhage was determined by CT and/or MR whenever need- ed to confirm the presence of a venous hemorrhagic infarct in the perfusion area of cerebral veins and/ or blood in the subarachnoid space and/or throm- bosed sinuses/veins. The thrombus location in cer- ebral veins and major cerebral venous sinuses was determined by CTV and/or MRV. An initial CT was typically used as an accurate and fast method to detect hemorrhagic lesions and CTV as a fast and reliable method to investigate the structure of deep cerebral sinuses/veins.22 Brain CT was performed on a CT 40-slice mul- ti-detector row CT scan (SIEMENS SOMATOM Sensation Open 40). CT imaging was obtained with a 3-mm section thickness through the posterior fos- sa and basal brain structures and a 4.8-mm section thickness through the supratentorial hemispheres. CTV, as a fast thin-section volumetric helical CT ex- amination, was performed with a time-optimized bolus of contrast medium to enhance the cerebral venous system. A 75–100 mL non-ionic contrast medium (iodine, 300 mg/mL) was administered at a rate of 3 mL/sec with a 45-second pre-scanning delay. Helical scanning was performed on the cra- nial region, from the first vertebral body to the calvaria vertex. Post-processing included two-di- mensional (2D) and sometimes three-dimensional (3D) multiplanar images, slice thickness 3mm with 1 mm overlap. MRI was performed on a 1.5T unit (Philips Achieva 1.5T MRI system) using a standardized protocol for brain examination, including the fol- lowing sequences: axial T1, axial T2, axial fluid- attenuated inversion recovery (FLAIR), T2*, diffu- sion-weighted imaging (DWI) sequences, apparent diffusion coefficient (ADC) map and axial, sagittal and coronal T1 after the application of paramag- netic contrast agent. MR images were not used for statistics and were therefore not described in fur- ther detail. Data analysis A multiple linear regression was performed to test the effects upon clinical outcome of age, gender, predisposing/precipitating factors (e.g. genetic or acquired thrombophilia, steroid hormonal ther- apy, autoimmune disorders, malignancy, preg- nancy), clinical signs/symptoms (e.g. headache, seizures, focal signs, nausea/vomiting, disturbed consciousness), and CT diagnostics (e.g herniation, brain edema, sulcal effacement, ventricular com- pression). The impact of any pattern and burden of venous sinus/deep vein thrombosis on venous stroke was tested. A Spearman rank correlation co- efficient was determined. The patients were divided into 2 groups. The first group consisted of patients who were diag- nosed at admission as having isolated SAH asso- ciated with CVST, and the second group included patients who initially suffered from hemorrhagic venous brain infarction. The outcomes were clini- cally ranked according to the modified Rankin score of 0 to 6.23 The clinical outcome results were revised by a neurologist experienced in cerebro- vascular pathology. After comparing the baseline and demographic data of the groups, the laboratory and radiologi- cal data of the 2 groups were compared using the Mann-Whitney Rank sum test and/or Spearman rank-order correlation, as appropriate. The statisti- cal analyses were performed using the Sigma plot statistic package. Results With the multiple linear regression test, a positive correlation between CT diagnostic scores at admis- sion and mRS outcome scores at discharge was observed (Spearman rank correlation coefficient, R Radiol Oncol 2022; 56(3): 303-310. Kobal J et al. / Isolated SAH and hemorrhagic infarction306 ever, glucocorticoid/sex steroid therapy was most frequently observed (Table 1). The most frequently reported symptoms/signs on admission in both groups are presented in Table 2. Headache and seizures predominated in both groups. There was a statistically significant difference between the groups (Mann-Whitney Rank Sum Test, p = 0.026; Table 2) in the mRS outcome score at the control examination but not at discharge. The iSAH group had a significantly better outcome than the hemorrhagic infarction group. Nevertheless, the number of thrombosed venous sinuses/deep veins in the iSAH group was significantly greater (p = 0.002). In this group, we also observed signifi- cantly more occlusions of a confluence of sinuses (p = 0.015), transverse sinuses (p = 0.015), sigmoid sinuses (p = 0.023), and jugular vein bulbs (p = 0.013) than in the hemorrhagic infarction group. In contrast, there was a larger number of sulcal oblit- eration (p = 0.014) and edema formation (p = 0.004) in the hemorrhagic infarction group. There was no statistically significant difference between the two groups of patients (p = 0.128) in the number of her- niations. However, herniation was observed in all 3 patients with a fatal outcome in the hemorrhagic infarction group (mRS 6); minor subfalcine hernia- tion was observed in another patient in this group (Table 3). Discussion In this retrospective observational study, we found that patients with CVT who suffered initially from iSAH had a better clinical outcome than patients suffering from hemorrhagic brain infarct. Isolated SAH patients had significantly more venous si- nuses and deep veins obstructed than those in the hemorrhagic infarction group. Due to the CT ve- nography that was routinely performed, however, the detection of cortical vein thrombosis was not ac- curate enough to perform statistics.24 Nevertheless, we did observe a specific pattern of occluded si- nuses in this group. The confluence of sinuses, transverse sinuses, sigmoid sinuses, and jugular vein bulbs were occluded significantly more often than in the hemorrhagic infarction group. Despite more sinus/deep vein obstructions in the iSAH group, all the fatal cases occurred in the hemorrhagic infarction group as also signifi- cantly more edema formation/sulcal effacement. We observed gender differences, with men signifi- cantly predominating in the isolated SAH group TABLE 1. The basic data and predisposing/precipitating factors in isolated subarachnoid hemorrhage (iSAH) and haemorrhagic infarction groups of patients iSAH group N = 8 Hem. inf. group N = 15 Age (mean ± SD) 49.3 ± 16.2 47.9 ± 16.8 Gender 6 M, 2 W 4 M, 11 W* Genetic thrombophilia (%) 4 (50.0%) 2 (13.3%) Acquired thrombophilia (%) 0 (0%) 4 (26.7%) Autoimmune disorder (%) 4 (50.0%) 4 (26.7%) Hypothyroid disorder (%) 1 (12.5%) 1 (6.7%) Venous sinuses injury (%) 1 (12.5%) 0 (0%) Malignancy (%) 1 (12.5%) 1 (6.7%) Pregnancy (%) 0 (0%) 1 (6.7%) Glucocorticoid/sex steroid therapy (%) 1 (12.5%) 6 (40.0%) * statistically significant difference between the two at p < 0.05; Hem. inf. group = haemorrhagic infarction groups; M = men; N = number; W = women TABLE 2. Clinical signs on admission in isolated subarachnoid hemorrhage (iSAH) and haemorrhagic infarction groups iSAH group N = 8 Hem. Inf group N = 15 Headache (%) 6 (75.0%) 9 (60.0%) Seizure (%) 3 (37.5%) 8 (53.3%) Focal signs (%) 2 (25.0%) 5 (33.3%) Nausea/vomiting (%) 2 (25.0%) 3 (20.0%) Confusion (%) 0 (0%) 2 (13.3%) Disturbed consciousness(%) 0 (0%) 4 (26.7%) Hem. inf. group = haemorrhagic infarction groups; N = number = 0.850; p < 0.001). A positive correlation was also found between CT diagnostic scores at admission and mRS outcome scores at a 6-month control (R = 0.911; p < 0.001). There was no correlation between age, gender, predisposing/precipitating factors or clinical signs/symptoms at admission and the mRS outcome at discharge or at the 6-month control. The iSAH group consisted of 8 patients (6 men) aged 49.3 ± 16.2 years. In 7 of them, we identified isolated cortical SAH and in 1, perimesencephal. The hemorrhagic infarction group was composed of 15 patients (4 men) aged 47.9 ± 16.8 years. We observed significant gender differences (p = 0.032), with men significantly predominating in the iSAH group and women in the hemorrhagic infarction group. Genetic thrombophilia and autoimmune disorders prevailed among the risk/provoking fac- tors in the iSAH group. In the hemorrhagic infarc- tion group, the results were more dispersed; how- Radiol Oncol 2022; 56(3): 303-310. Kobal J et al. / Isolated SAH and hemorrhagic infarction 307 and women in the hemorrhagic infarction group. Significant differences in predisposing/precipitat- ing factors were not found. There were also no sig- nificant differences regarding clinical symptoms/ signs between the groups. Previous experience has indicated that hemor- rhagic infarction is a major long-term factor of un- favorable outcome10, especially when it presents as a space-occupying lesion.25 In our patients who presented with hemorrhagic infarction accompa- nied by edema formation/sulcal obliteration, the clinical outcome at the control examination was significantly worse than in isolated SAH patients. There were also 3 lethal outcomes (mRS 6) among TABLE 3. Comparison of thrombosed veins/sinuses (CVS), oedema formation, herniation, sulcal obliteration, modified Rankin Scores (mRs) at discharge and control examination in both groups of patients iSAH group N = 8 Hem. Inf group N = 15 Average No. of thrombosed CVS (median, 25%, 75% percentiles) 4 (25% 3.25, 75% 5.75) 2 (25% 1, 75% 3)* Sulcal obliteration 0 (0.0%) 13 (86.7%)* Subfalcine/uncal herniation 0 (0.0%) 4 (26.7%) Oedema formation 2 (25.0%) 8 (53.3%)* Average mRS at discharge (median, 25% , 75% percentiles) 1 (25% 0, 75% 1.75) 2 (25% 0, 75% 3) Average mRS at control (median, 25% , 75% percentiles) 0 (25% 0, 75% 0) 1 (25% 0, 75% 3)* *statistically significant difference between the two groups at p < 0.05; Hem. inf. group = haemorrhagic infarction groups; iSAH = isolated subarachnoid hemorrhage; N = number FIGURE 1. A 23-year old woman with headache followed by seizure and focal neurological deficit MRI on admission showed no focal lesions/oedema (A); contrast material-enhanced (CE) T1 and T2 showed occlusion of the left sigmoid sinus (B) and left transverse (C). Despite immediate anticoagulant treatment (fractioned heparin), the next day the patient became drowsy. CT revealed hemorrhagic infarction; in addition to the transverse sinus (arrow), the Labbe vein was suspected to be occluded due to the infarction territory (D). Decompressive craniotomy failed to prevent progression to irreversible coma (E,F). A B C D E F Radiol Oncol 2022; 56(3): 303-310. Kobal J et al. / Isolated SAH and hemorrhagic infarction308 hemorrhagic infarction patients. In each of those patients, we observed brain herniation within 24 hours of admission. Brain edema and sulcal oblit- eration were also present in each; brain edema of predominately the infratentorial region due to deep venous system obliteration was found in 1 of them. Edema formation, sulcal obliteration, and herniation are indicators of a space-occupying le- sion and a worse clinical outcome.25 Venous infarc- tion formation may be due to venous reflux in the cerebral veins, which have no valves; or perhaps, similarly to superficial communicating veins, due to increased venous and capillary tissue pressure leading to diapedesis of erythrocytes, blood-brain barrier disruption, blood vessel damage and blood leak, all of which further lead to hemorrhagic in- farction formation26. Given a rigid skull and me- ninges, the brain cannot distend, which leads to in- creased intracranial pressure, as also reduced cer- ebral perfusion pressure, cerebral blood flow, and oxygenation.27 However, given the experimental study by Ungersböck K. et al.18, which revealed the progression of thrombosis from the venous sinus to the bridging and cortical communicating veins completing an obstruction of venous collaterals, we presume this same progression in our patients and its eventuating a fatal outcome. The occlusion of the venous sinus alone seems to be not enough to cause cerebral infarction (Figure 1).18 In addi- tion, it seems that iSAH in CVT might be connected to a specific pattern of sinuses being occluded. The patients with iSAH, either cortical or in the posterior fossa (e.g., perimesencephal), in our study had an excellent outcome in that they were practically free of functional disability at the con- trol examination. None of them showed sulcal obliteration, although 3 of them experienced su- pratentorial edema. Isolated SAH patients were also found to have a good outcome in previous studies and reports.9,14,15,28 In the present study, we focused on clinical and radiological features that may influence different presentations of CVT. The previous studies examined patients experiencing either iSAH 9,15 or hemorrhagic brain infarct.10 We found no clinical studies focusing on the manner of iSAH and hemorrhagic venous brain infarct forma- tion after CVT. Venous blood flows along veins by the pressure gradient to the nearest venous sinus.16,29 If there is no communication through which blood flows, then venous stasis, edema, blood leakage, and in- farction develop.26 The leakage and formation of iSAH presumably evolve from congested super- ficial communicating veins and/or overstretched thin-walled bridging veins.7,27 According to a previous experimental study, cortical SAH/perimesencephalic SAH in CVT pa- tients indicate increased blood flow in the super- ficial communicating veins from which the bridg- ing veins originate.18 Persistent communication through the communicating/bridging venous sys- tem may reduce venous stasis and attenuate brain edema when the venous sinus is occluded. We suggest that iSAH is an indicator of that process. It seems that in patients who initially suffer iSAH, venous blood flow is partly transferred from the occluded veins/sinuses to superficial anastomotic veins, which carry venous blood towards venous FIGURE 2. A 59-year old man was examined after 5 days of headaches and a seizure. CT revealed bilateral cortical subarachnoid hemorrhage (SAH) and moderate diffuse brain edema, but no hemorrhagic infarction was formed (A). An extensive thrombosis of cerebral sinuses/veins including the superior sagittal sinus, transversal sinuses, left sigmoid sinus and jugular bulb was observed. The right transversal sinus was occluded to the point of Labbe vein inflow (B), arrow showing confluence of vein to sinus). Fractured heparin and later warfarin were introduced; the patient scored 0 according modified Rankin Score (mRs) at control examination. Complete recanalization of the occluded sinuses occurred (C). A B C Radiol Oncol 2022; 56(3): 303-310. Kobal J et al. / Isolated SAH and hemorrhagic infarction 309 sinuses that are not occluded; blood flow is also partly transferred by thin superficial communicat- ing veins leading blood towards meningeal veins and perhaps diploic veins (Figure 2).7,30 The findings in our patients are consistent with a recent neuroradiological study demonstrating that occlusion of the Labbe’s vein significantly correlates with occlusion of the ipsilateral transversal sinus.31 Predisposing/precipitating factors in the iSAH and hemorrhagic infarction groups were not sig- nificantly different. Five women were receiving sex steroid therapy, 1 of which was in the isolated SAH group. One man in the hemorrhagic infarc- tion group was receiving corticosteroid therapy. Hence, gender differences between the iSAH and hemorrhagic infarction groups cannot be ex- plained by the effect of women-specific risk factors. Men predominated in our iSAH group, similar to a study from India.7 In contrast, a French study of 22 of such patients included only 4 men.9 In each of the case series, sampling was relatively small, pos- sibly due to the rarity of the pathology; hence, bias is possible. Anticoagulant therapy was introduced in all the patients as recommended.32 In patients experiencing large hemispheric le- sions, a decompressive craniotomy was found to be effective.33 Decompressive craniotomy relieves pressure on patent venous pathways, although it does not open the occluded ones. We propose that craniotomy should be attempted soon enough to prevent large edema/sulcal displacement, which is followed by compression and thrombosis of super- ficial communicating veins (e.g., Labbe’s vein), as in line with recent updates/neuroradiologic stud- ies.31,33 Among the limitations of the present study are the retrospective and observational methods, since such methods may involve bias due to differences in the approach of various clinicians/radiologists. The examinations were likewise not performed ac- cording to a standardized protocol. This is a limita- tion in the value of the results. The available clini- cal results and radiological images were, however, reviewed and interpreted by an experienced clini- cal neurologist and neuroradiologist. At the same time, an observational method might be a strength, since it originates from real life and real clinical problems, possibly providing insights on how to perform future clinical and neuroradiological evaluations. Another limitation is the small num- ber of patients in the iSAH/hemorrhagic infarction groups, which can be explained by the rarity of the pathology and the strict inclusion criteria. In short, this retrospective study has shown that patients with CVT who have suffered from cortical subarachnoid hemorrhage have an excellent clini- cal outcome, despite a higher number of occluded deep cerebral veins/sinuses. Further, a specific pat- tern of occluded venous sinuses was found, a clue to which might be patent communicant superfi- cial venous pathways, e.g., vein of Labbe, vein of Trolard, and other less defined communicating cor- tical veins that drain to the nearest patent venous sinus. The pattern of sinuses that are occluded may have a role. Patients who suffered an early hemor- rhagic venous infarction had a worse outcome – a mass effect leading to brain edema and superficial vein obliteration may be the explanation. References 1. Coutinho JM, Zuurbier SM, Aramideh M, Stam J. 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