Progressive superficial siderosis despite complete remission of intracranial hypotension symptoms following epidural patching: Case report.

Spontaneous intracranial hypotension (SIH) commonly results from ventral spinal cerebrospinal fluid (CSF) leaks and epidural patches are advocated as first-line treatment. Complications such as superficial siderosis can arise but have previously been reported only in the context of long-term persistent, ongoing, CSF leak and SIH. We report a case of a patient with SIH from a ventral spinal CSF leak that was treated with epidural patching and experienced complete resolution of SIH. Four years later SIH symptoms recurred, and brain magnetic resonance imaging unexpectedly showed the interval accumulation of hemosiderin pigmentation on the cerebellum and brainstem during the period when the patient was without symptoms of SIH. This case uniquely demonstrates the progression of superficial siderosis despite the apparent resolution of SIH. Our findings suggest two divergent pathophysiological outcomes from spinal ventral dural tear: (1) CSF loss causing SIH; and (2) persistent low-level bleeding arising from the spinal dural tear leading to superficial siderosis. These divergent pathophysiologies had a discordant response to epidural patching. Epidural patching successfully treated the SIH but did not prevent the progression of superficial siderosis, indicating that some patients may require more than epidural patching despite symptom resolution. This case highlights the need for post-treatment monitoring protocols in patients with ventral spinal CSF leaks and SIH and raises important questions about the adequacy of epidural patching in certain SIH cases arising from ventral spinal CSF leak.

Pancreatic iron in pediatric transfusion-dependent beta-thalassemia patients: A longitudinal MRI study.

BACKGROUND: In pediatric transfusion-dependent thalassemia (TDT) patients, we evaluated the prevalence, pattern, and clinical associations of pancreatic siderosis and the changes in pancreatic iron levels and their association with baseline and changes in total body iron balance. PROCEDURE: We considered 86 pediatric TDT patients consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network. Iron overload (IO) was quantified by R2* magnetic resonance imaging (MRI). RESULTS: Sixty-three (73%) patients had pancreatic IO (R2* > 38 Hz). Global pancreas R2* values were significantly correlated with mean serum ferritin levels, MRI liver iron concentration (LIC) values, and global heart R2* values. Global pancreas R2* values were significantly higher in patients with altered versus normal glucose metabolism. Thirty-one patients also performed the follow-up MRI at 18 ± 3 months. Higher pancreatic R2* values were detected at the follow-up, but the difference versus the baseline MRI was not significant. The 20% of patients with baseline pancreatic IO showed no pancreatic IO at the follow-up. The 46% of patients without baseline pancreatic IO developed pancreatic siderosis. The changes in global pancreas R2* between the two MRIs were not correlated with baseline serum ferritin levels, baseline, final, and changes in MRI LIC values, or baseline pancreatic iron levels. CONCLUSIONS: In children with TDT, pancreatic siderosis is a frequent finding associated with hepatic siderosis and represents a risk factor for myocardial siderosis and alterations of glucose metabolism. Iron removal from the pancreas is exceptionally challenging and independent from hepatic iron status.

Post-transfusion severe headache in a patient with thalassemia with superficial siderosis of the central nervous system: a case report and literature review.

BACKGROUND: Patients with severe thalassemia may experience adverse effects from transfusion such as fever, rash, and iron overload after long-term transfusion therapy. Severe headaches as a side effect of blood transfusion in patients with thalassemia are not commonly observed, especially when combined with superficial siderosis of the central nervous system, which is easily misdiagnosed and requires excessive examination and treatment. CASE PRESENTATION: A 31-year-old woman was admitted with severe headache and vomiting over 3 days following blood transfusion. She was diagnosed with intermediate α-thalassemia at 2 years of age and had a history of irregular blood transfusions. Physical examination revealed horizontal nystagmus with no other abnormal neurological signs. Magnetic resonance (MR) imaging, MR venography, MR arteriography, and cerebrospinal fluid analysis were normal. However, susceptibility-weighted imaging showed abnormal signals in the bilateral and fourth ventricles. Initial antibiotics, antivirals, decompression of intracranial pressure, iron chelation, and symptomatic treatments were administered; subsequently, small intermittent blood transfusions were cautiously administered for severe anemia. The patient's headache was gradually relieved, and she was discharged on day 9. At the 5-month follow-up, the patient's headache recurred following another transfusion. CONCLUSIONS: Severe post-transfusion headache in patients with thalassemia has not been fully recognized and is easily misdiagnosed, leading to excessive examination and treatment. Understanding the clinical features of transfusion-related headaches can help identify this complication, but the exact pathophysiological mechanism requires further research.

Surgical closure of spinal cerebrospinal fluid leaks improves symptoms in patients with superficial siderosis.

BACKGROUND AND PURPOSE: Spinal cerebrospinal fluid (CSF) leaks may cause a myriad of symptoms, most common being orthostatic headache. In addition, ventral spinal CSF leaks are a possible etiology of superficial siderosis (SS), a rare condition characterized by hemosiderin deposits in the central nervous system (CNS). The classical presentation of SS involves ataxia, bilateral hearing loss, and myelopathy. Unfortunately, treatment options are scarce. This study was undertaken to evaluate whether microsurgical closure of CSF leaks can prevent further clinical deterioration or improve symptoms of SS. METHODS: This cohort study was conducted using data from a prospectively maintained database in two large spontaneous intracranial hypotension (SIH) referral centers in Germany and Switzerland of patients who meet the modified International Classification of Headache Disorders, 3rd edition criteria for SIH. Patients with spinal CSF leaks were screened for the presence of idiopathic infratentorial symmetric SS of the CNS. RESULTS: Twelve patients were included. The median latency between the onset of orthostatic headaches and symptoms attributed to SS was 9.5 years. After surgical closure of the underlying spinal CSF leak, symptoms attributed to SS improved in seven patients and remained stable in three. Patients who presented within 1 year after the onset of SS symptoms improved, but those who presented in 8-12 years did not improve. We could show a significant association between patients with spinal longitudinal extrathecal collections and SS. CONCLUSIONS: Long-standing untreated ventral spinal CSF leaks can lead to SS of the CNS, and microsurgical sealing of spinal CSF leaks might stop progression and improve symptoms in patients with SS in a time-dependent manner.

Impact of previous statin use on first intracerebral hemorrhage in cerebral amyloid angiopathy.

OBJECTIVES: Statins have been associated with an increased risk of spontaneous intracerebral hemorrhage (ICH), but without dedicated study in cerebral amyloid angiopathy (CAA). We aimed to evaluate the association between previous statin treatment and radiological hemorrhagic lesions in a CAA population during a first lobar ICH event. MATERIALS AND METHODS: We retrospectively included all patients meeting the modified Boston criteria for probable CAA and admitted for a first lobar ICH between 2010 and 2021 at Rouen University Hospital. Patients were classified as having previous statin treatment or not. We compared the ICH volume, the number of associated cerebral microbleeds (CMBs), and cortical superficial siderosis (CSS) according to previous statin treatment or not. We also compared functional outcomes and ICH recurrence during the follow-up period between the two groups. RESULTS: We included 99 patients, 27 of whom had statin treatment prior to their ICH. The ICH volume and the number of CMBs did not differ between groups. Disseminated CSS was initially more frequent in the statin group (88% versus 57%; P=0.019), but this was no longer significant after adjustment for antiplatelet treatment (P=0.13). The long-term outcome was similar between the two groups with no increased risk of ICH recurrence in the statin-treated group (29.63% versus 23.61%, P=0.54). CONCLUSIONS: Previous statin treatment was not associated with more severe hemorrhagic lesions in CAA in terms of ICH volume or number of microbleeds, but a trend for increased disseminated CSS was highlighted, which will require further larger studies.

Cortical superficial siderosis is associated with reactive astrogliosis in cerebral amyloid angiopathy.

BACKGROUND: Cortical superficial siderosis (cSS) has recently emerged as one of the most important predictors of symptomatic intracerebral hemorrhage and is a risk factor for post-stroke dementia in cerebral amyloid angiopathy (CAA). However, it remains unknown whether cSS is just a marker of severe CAA pathology or may itself contribute to intracerebral hemorrhage risk and cognitive decline. cSS is a chronic manifestation of convexal subarachnoid hemorrhage and is neuropathologically characterized by iron deposits in the superficial cortical layers. We hypothesized that these iron deposits lead to local neuroinflammation, a potentially contributory pathway towards secondary tissue injury. METHODS: Accordingly, we assessed the distribution of inflammatory markers in relation to cortical iron deposits in post-mortem tissue from CAA cases. Serial sections from the frontal, parietal, temporal, and occipital lobes of nineteen autopsy cases with CAA were stained with Perls' Prussian blue (iron) and underwent immunohistochemistry against glial fibrillary acidic protein (GFAP, reactive astrocytes) and cluster of differentiation 68 (CD68, activated microglia/macrophages). Digitized sections were uploaded to the cloud-based Aiforia® platform, where deep-learning algorithms were utilized to detect tissue, iron deposits, and GFAP-positive and CD68-positive cells. RESULTS: We observed a strong local relationship between cortical iron deposits and reactive astrocytes. Like cSS-related iron, reactive astrocytes were mainly found in the most superficial layers of the cortex. Although we observed iron within both astrocytes and activated microglia/macrophages on co-stains, there was no clear local relationship between the density of microglia/macrophages and the density of iron deposits. CONCLUSION: Iron deposition resulting from cSS is associated with local reactive astrogliosis.

[Classical cortical superficial siderosis presenting as extensive higher brain dysfunction with hypoperfusion in the frontoparietal lobe on the 123I-IMP-SPECT: a case report].

A 72-year-old male developed neurological symptoms such as difficulty in charging his electronic money card and making his mobile-phone call ten months before admission. On admission, neurological examination revealed extensive higher brain dysfunction such as impairment in recent memory, executive function disorders, constructional disturbance, agraphia and acalculia. Brain MRI revealed a low intensity lesion on the surface of the cerebral cortex diffusely and symmetrically on T2*-weighted images. MRI images are consistent with superficial siderosis. However, the lack of hemosiderin deposition in the brain stem and cerebellar hemisphere was atypical of the classical type of superficial siderosis. 123I-IMP-SPECT revealed hypoperfusion dominantly in the left hemisphere, particularly in the left frontal and parietal lobes. According to the Boston criteria, the patient with the cerebral microbleeds and cortical superficial siderosis was diagnosed with probable CAA (cerebral amyloid angiopathy).

Mechanistic Implications of Cortical Superficial Siderosis in Patients With Mixed Location Intracerebral Hemorrhage and Cerebral Microbleeds.

BACKGROUND AND OBJECTIVES: Hypertensive cerebral small vessel disease (HTN-cSVD) is the predominant microangiopathy in patients with a combination of lobar and deep cerebral microbleeds (CMBs) and intracerebral hemorrhage (mixed ICH). We tested the hypothesis that cerebral amyloid angiopathy (CAA) is also a contributing microangiopathy in patients with mixed ICH with cortical superficial siderosis (cSS), a marker strongly associated with CAA. METHODS: Brain MRIs from a prospective database of consecutive patients with nontraumatic ICH admitted to a referral center were reviewed for the presence of CMBs, cSS, and nonhemorrhagic CAA markers (lobar lacunes, centrum semiovale enlarged perivascular spaces [CSO-EPVS], and multispot white matter hyperintensity [WMH] pattern). The frequencies of CAA markers and left ventricular hypertrophy (LVH), a marker for hypertensive end-organ damage, were compared between patients with mixed ICH with cSS (mixed ICH/cSS[+]) and without cSS (mixed ICH/cSS[-]) in univariate and multivariable models. RESULTS: Of 1,791 patients with ICH, 40 had mixed ICH/cSS(+) and 256 had mixed ICH/cSS(-). LVH was less common in patients with mixed ICH/cSS(+) compared with those with mixed ICH/cSS(-) (34% vs 59%, p = 0.01). The frequencies of CAA imaging markers, namely multispot pattern (18% vs 4%, p < 0.01) and severe CSO-EPVS (33% vs 11%, p < 0.01), were higher in patients with mixed ICH/cSS(+) compared with those with mixed ICH/cSS(-). In a logistic regression model, older age (adjusted odds ratio [aOR] 1.04 per year, 95% CI 1.00-1.07, p = 0.04), lack of LVH (aOR 0.41, 95% CI 0.19-0.89, p = 0.02), multispot WMH pattern (aOR 5.25, 95% CI 1.63-16.94, p = 0.01), and severe CSO-EPVS (aOR 4.24, 95% CI 1.78-10.13, p < 0.01) were independently associated with mixed ICH/cSS(+) after further adjustment for hypertension and coronary artery disease. Among ICH survivors, the adjusted hazard ratio of ICH recurrence in patients with mixed ICH/cSS(+) was 4.65 (95% CI 1.38-11.38, p < 0.01) compared with that in patients with mixed ICH/cSS(-). DISCUSSION: The underlying microangiopathy of mixed ICH/cSS(+) likely includes both HTN-cSVD and CAA, whereas mixed ICH/cSS(-) is likely driven by HTN-cSVD. These imaging-based classifications can be important to stratify ICH risk but warrant confirmation in studies incorporating advanced imaging/pathology.

Quantitative measurement of cortical superficial siderosis in cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) is a cerebrovascular disease affecting the small arteries in the brain with hallmark depositions of amyloid-ß in the vessel wall, leading to cognitive decline and intracerebral hemorrhage (ICH). An emerging MRI marker for CAA is cortical superficial siderosis (cSS) as it is strongly related to the risk of (recurrent) ICH. Current assessment of cSS is mainly done on T2*- weighted MRI using a qualitative score consisting of 5 categories of severity which is hampered by ceiling effects. Therefore, the need for a more quantitative measurement is warranted to better map disease progression for prognosis and future therapeutic trials. We propose a semi-automated method to quantify cSS burden on MRI and investigated it in 20 patients with CAA and cSS. The method showed excellent inter-observer (Pearson's 0.991, P < 0.001) and intra-observer reproducibility (ICC 0.995, P < 0.001). Furthermore, in the highest category of the multifocality scale a large spread in the quantitative score is observed, demonstrating the ceiling effect in the traditional score. We observed a quantitative increase in cSS volume in two of the 5 patients who had a 1 year follow up, while the traditional qualitative method failed to identify an increase because these patients were already in the highest category. The proposed method could therefore potentially be a better way of tracking progression. In conclusion, semi-automated segmenting and quantifying cSS is feasible and repeatable and may be used for further studies in CAA cohorts.

Preceding symptoms and temporal development of cortical superficial siderosis in cerebral amyloid angiopathy: a case report.

BACKGROUND: We present a case illustrating evolution of symptoms and brain magnetic resonance imaging in cortical superficial siderosis. CASE PRESENTATION: A 74-year-old man with no prior medical history presented with transient focal neurological episodes with subtle imaging changes. There was no evidence of cortical superficial siderosis. Two weeks later, the patient was readmitted with new episodes, and had developed cortical superficial siderosis adjacent to a cerebral microbleed. Transient focal neurological episode secondary to cortical superficial siderosis was diagnosed together with probable cerebral amyloid angiopathy. CONCLUSION: Clinical symptoms may precede the development of cortical superficial siderosis prior to being detectable on brain MRI. This case highlights the temporal development of cortical superficial siderosis.

Gastric Glandular Siderosis but not Lamina Propria Siderosis is Associated With High Serum Ferritin Levels.

Three histologic patterns of gastric siderosis (GS) are described: pattern A (predominantly in lamina propria stromal cells-gastric lamina propria siderosis [GLPS]), pattern B (mostly extracellular crystalline iron) and pattern C (predominantly in glandular epithelium-gastric glandular siderosis [GGS]). This study aimed to analyze the association of GGS with clinicopathologic features using 3 cohorts. Cohort #1 consisted of 76 gastric siderosis cases. Upon classifying the cases into 3 groups by percentage of glandular involvement (negative, 1% to 5%, ≥5% GGS), the degree of GGS was positively associated with serum ferritin levels ( P =0.002), transferrin saturation ( P =0.003), and history of blood transfusion ( P =0.009). After excluding cases with coarse extracellular crystalline iron, cohort #1 was reclassified into 3 groups by degree of GLPS (no, rare [discernible at ×20 or ×40], overt [readily visible at low power]). The degree of GLPS was positively correlated with oral iron pill use ( P =0.01), but not serum ferritin levels or transferrin saturation. Cohort #2 contained 31 gastric samples from patients with hereditary hemochromatosis, most received phlebotomy treatment. GGS was identified in 2 (6.4%) patients; both had high ferritin levels. Cohort #3 included 38 gastric samples from patients with cirrhosis. Three (8%) cases showed GGS; serum ferritin level was available for 1 case and was elevated. These results indicate that GGS is associated with systemic iron overload, while GLPS is correlated with oral iron pill use. The identification of GGS, especially when it's ≥5%, should trigger further workup for potential systemic iron overload and underlying etiologies.

Axillary Cutaneous Hemosiderosis in a Patient With Hyperhidrosis, After Intravenous Iron Infusion.

ABSTRACT: Hemosiderosis consists of an iron deposit in tissues, which does not cause organic damage to them. However, in the case of the skin, being an organ exposed to sight, siderosis can produce a brownish coloration that is aesthetically discomforting for the individual. Most cutaneous sideroses are because of venous insufficiency with hemorrhagic extravasation. There is also a group secondary to iron extravasation in the injection site of the transfusion. However, there are very few cases in which an intravenous injection of an iron preparation has produced diffuse siderosis in extensive areas of the skin. We present the case of a 31-year-old woman with hyperhidrosis, who was transfused as a result of postpartum hemorrhage and, shortly after receiving an intravenous iron infusion, developed extensive hyperpigmentation in both axillae.

Intraventricular hemorrhage in term infants: a single institutional experience between 2016 and 2020.

PURPOSE: Intraventricular hemorrhage (IVH) of prematurity is a known complication of preterm birth. Intraventricular hemorrhage in term infants is much less commonly encountered. To address the lack of information in the current literature concerning this demographic, we offer demographic and image findings that demonstrate etiology and predict the need for permanent cerebrospinal fluid (CSF) diversion. METHODS: A prospectively maintained database was queried for all patients with intraventricular hemorrhage from 2016 to 2020 treated at our institution. Demographic data and etiology were collected, along with need for and timing of surgical intervention. RESULTS: A total of 150 IVH patients were identified. Of these patients, 138 were excluded due to prematurity. Twelve patients were born at term with IVH. All patients were followed for at least 8 months. Seven patients (58.3%) underwent ventriculoperitoneal (VP) shunt placement, performed between 4 days and 4 months of age. Superficial siderosis detected by MRI during in-patient stay or follow-up showed a sensitivity of 100% and specificity of 60% for the future development of post-hemorrhagic hydrocephalus (PHH) (p < 0.05). All full-term infants who developed PHH (n = 7, 58.3%) obtained a VP shunt. CONCLUSION: IVH in term infants occurs infrequently when compared to IVH of prematurity. Etiology of IVH in term infants remains difficult to ascertain, but the majority of patients did demonstrate risk factors. The presence of superficial siderosis on MRI significantly predicted the development of PHH and eventual need for CSF diversion.

Postoperative Spinal Cerebrospinal Fluid-Venous Fistulas Associated With Dural Tears in Patients With Intracranial Hypotension or Superficial Siderosis-A Digital Subtraction Myelography Study.

BACKGROUND: Postoperative spinal cerebrospinal fluid (CSF) leaks are common but rarely cause extensive CSF collections that require specialized imaging to detect the site of the dural breach. OBJECTIVE: To investigate the use of digital subtraction myelography (DSM) for patients with extensive extradural CSF collections after spine surgery. METHODS: A retrospective review was performed to identify a consecutive group of patients with extensive postoperative spinal CSF leaks who underwent DSM. RESULTS: Twenty-one patients (9 men and 12 women) were identified. The mean age was 46.7 years (range, 17-75 years). The mean duration of the postoperative CSF leak was 3.3 years (range, 3 months to 21 years). MRI showed superficial siderosis in 6 patients. DSM showed the exact location of the CSF leak in 19 (90%) of the 21 patients. These 19 patients all underwent surgery to repair the CSF leak, and the location of the CSF leak could be confirmed intraoperatively in all 19 patients. In 4 (19%) of the 21 patients, DSM also showed a CSF-venous fistula at the same location as the postoperative dural tear. CONCLUSION: In this study, DSM had a 90% detection rate of visualizing the exact site of the dural breach in patients with extensive postoperative spinal CSF leaks. The coexistence of a CSF-venous fistula in addition to the primary dural tear was present in about one-fifth of patients. The presence of a CSF-venous fistula should be considered if CSF leak symptoms persist in spite of successful repair of a durotomy.

Cerebellar Superficial Siderosis in Cerebral Amyloid Angiopathy on 1.5T T2*-Weighted Imaging.

BACKGROUND: Cerebellar superficial siderosis (SS) has been recently reported to be present in about 10% of both hereditary and sporadic cerebral amyloid angiopathy (CAA) on 3T MRI using primarily susceptibility-weighted imaging. OBJECTIVES: Our aim was to assess cerebellar SS in sporadic CAA patients using 1.5T T2*-weighted MRI and to evaluate possible underlying mechanisms. METHOD: We retrospectively screened MRI scans of sporadic probable CAA patients initially presenting with intracerebral hemorrhage-, acute subarachnoid hemorrhage- or cortical SS-related symptoms between September 2009 and January 2022 registered in our stroke database. Patients with familial CAA were excluded. On 1.5T T2*-weighted MRI, cerebellar SS (including kappa statistics for interobserver agreement) was assessed together with typical CAA hemorrhagic features and with the presence of supratentorial macrobleed and cortical SS adjacent to the tentorium cerebelli (TC) and TC hemosiderosis. RESULTS: We screened 151 patients and finally included 111 CAA patients (median age 77) with cerebellar SS observed in 6 (5%) patients. Cerebellar SS presence was associated with a higher number of supratentorial macrobleeds (median n = 3 vs. n = 1, p = 0.0012), presence of supratentorial macrobleed adjacent to the TC (p = 0.002), and TC hemosiderosis (p = 0.005). CONCLUSIONS: Cerebellar SS in CAA patients can be identified on 1.5T T2*-weighted imaging. Associated MRI characteristics suggest contamination from supratentorial macrobleeds.

Anterior horn damage in brachial multisegmental amyotrophy with superficial siderosis and dural tear: an autopsy case report.

BACKGROUND: Patients with superficial siderosis (SS) rarely show brachial multisegmental amyotrophy with ventral intraspinal fluid collection accompanied with dural tear. CASE PRESENTATION: We describe spinal cord pathology of a 58-year-old man who developed brachial multisegmental amyotrophy with ventral intraspinal fluid collection from the cervical to lumbar spinal levels accompanied with SS, dural tear, and snake-eyes appearance on magnetic resonance imaging (MRI). Radiological and pathological analyses detected diffuse and prominent superficial deposition of hemosiderin in the central nervous system. Snake-eyes appearance on MRI expanded from the C3 to C7 spinal levels without apparent cervical canal stenosis. Pathologically, severe neuronal loss at both anterior horns and intermediate zone was expanded from the upper cervical (C3) to middle thoracic (Th5) spinal gray matter, and these findings were similar to compressive myelopathy. CONCLUSION: Extensive damage of the anterior horns in our patient may be due to dynamic compression induced by ventral intraspinal fluid collection.

Subarachnoid CSF hyperintensities at 7 tesla FLAIR MRI: A novel marker in cerebral amyloid angiopathy.

BACKGROUND: We observed subarachnoid cerebrospinal fluid (CSF) hyperintensities at non-contrast 7-tesla (T) fluid-attenuated inversion recovery (FLAIR) MRI, frequently topographically associated with cortical superficial siderosis (cSS), in participants with cerebral amyloid angiopathy (CAA). To systemically evaluate these CSF hyperintensities we investigated their frequency and anatomical and temporal relationship with cSS on 7T and 3T MRI in hereditary Dutch-type CAA (D-CAA), sporadic CAA (sCAA), and non-CAA controls. METHODS: CAA participants were included from two prospective natural history studies and non-CAA controls from a 7T study in healthy females and females with ischemic stroke. CSF hyperintensities were scored by two independent observers. RESULTS: We included 38 sCAA participants (mean age 72y), 50 D-CAA participants (mean age 50y) and 44 non-CAA controls (mean age 53y, 15 with stroke). In total 27/38 (71 %, 95 %CI 56-84) sCAA and 23/50 (46 %, 95 %CI 33-60) D-CAA participants had subarachnoid CSF hyperintensities at baseline 7T. Most (96 %) of those had cSS, in 54 % there was complete topographical overlap with cSS. The remaining 46 % had ≥1 sulcus with CSF hyperintensities without co-localizing cSS. None of the healthy controls and 2/15 (13 %, 95 %CI 2-41, 100 % cSS overlap) of the stroke controls had CSF hyperintensities. In 85 % of the CAA participants CSF hyperintensities could retrospectively be identified at 3T. Of the 35 CAA participants with follow-up 7T after two years, 17/35 (49 %) showed increase and 6/35 (17 %) decrease of regional CSF hyperintensities. In 2/11 (18 %) of participants with follow-up who had baseline CSF hyperintensities without overlapping cSS, new cSS developed at those locations. CONCLUSIONS: Subarachnoid CSF hyperintensities at 7T FLAIR MRI occur frequently in CAA and are associated with cSS, although without complete overlap. We hypothesize that the phenomenon could be a sign of subtle plasma protein or blood product leakage into the CSF, resulting in CSF T1-shortening.