Artificial intelligence for MRI stroke detection: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis aimed to assess the stroke detection performance of artificial intelligence (AI) in magnetic resonance imaging (MRI), and additionally to identify reporting insufficiencies. METHODS: PRISMA guidelines were followed. MEDLINE, Embase, Cochrane Central, and IEEE Xplore were searched for studies utilising MRI and AI for stroke detection. The protocol was prospectively registered with PROSPERO (CRD42021289748). Sensitivity, specificity, accuracy, and area under the receiver operating characteristic (ROC) curve were the primary outcomes. Only studies using MRI in adults were included. The intervention was AI for stroke detection with ischaemic and haemorrhagic stroke in separate categories. Any manual labelling was used as a comparator. A modified QUADAS-2 tool was used for bias assessment. The minimum information about clinical artificial intelligence modelling (MI-CLAIM) checklist was used to assess reporting insufficiencies. Meta-analyses were performed for sensitivity, specificity, and hierarchical summary ROC (HSROC) on low risk of bias studies. RESULTS: Thirty-three studies were eligible for inclusion. Fifteen studies had a low risk of bias. Low-risk studies were better for reporting MI-CLAIM items. Only one study examined a CE-approved AI algorithm. Forest plots revealed detection sensitivity and specificity of 93% and 93% with identical performance in the HSROC analysis and positive and negative likelihood ratios of 12.6 and 0.079. CONCLUSION: Current AI technology can detect ischaemic stroke in MRI. There is a need for further validation of haemorrhagic detection. The clinical usability of AI stroke detection in MRI is yet to be investigated. CRITICAL RELEVANCE STATEMENT: This first meta-analysis concludes that AI, utilising diffusion-weighted MRI sequences, can accurately aid the detection of ischaemic brain lesions and its clinical utility is ready to be uncovered in clinical trials. KEY POINTS: There is a growing interest in AI solutions for detection aid. The performance is unknown for MRI stroke assessment. AI detection sensitivity and specificity were 93% and 93% for ischaemic lesions. There is limited evidence for the detection of patients with haemorrhagic lesions. AI can accurately detect patients with ischaemic stroke in MRI.

Major Cardiovascular Events After Spontaneous Intracerebral Hemorrhage by Hematoma Location.

Importance: Survivors of spontaneous (ie, nontraumatic and with no known structural cause) intracerebral hemorrhage (ICH) have an increased risk of major cardiovascular events (MACEs), including recurrent ICH, ischemic stroke (IS), and myocardial infarction (MI). Only limited data are available from large, unselected population studies assessing the risk of MACEs according to index hematoma location. Objective: To examine the risk of MACEs (ie, the composite of ICH, IS, spontaneous intracranial extra-axial hemorrhage, MI, systemic embolism, or vascular death) after ICH based on ICH location (lobar vs nonlobar). Design, Setting, and Participants: This cohort study identified 2819 patients in southern Denmark (population of 1.2 million) 50 years or older hospitalized with first-ever spontaneous ICH from January 1, 2009, to December 31, 2018. Intracerebral hemorrhage was categorized as lobar or nonlobar, and the cohorts were linked to registry data until the end of 2018 to identify the occurrence of MACEs and separately recurrent ICH, IS, and MI. Outcome events were validated using medical records. Associations were adjusted for potential confounders using inverse probability weighting. Exposure: Location of ICH (lobar vs nonlobar). Main Outcomes and Measures: The main outcomes were MACEs and separately recurrent ICH, IS, and MI. Crude absolute event rates per 100 person-years and adjusted hazard ratios (aHRs) with 95% CIs were calculated. Data were analyzed from February to September 2022. Results: Compared with patients with nonlobar ICH (n = 1255; 680 [54.2%] men and 575 [45.8%] women; mean [SD] age, 73.5 [11.4] years), those with lobar ICH (n = 1034; 495 [47.9%] men and 539 [52.1%] women, mean [SD] age, 75.2 [10.7] years) had higher rates of MACEs per 100 person-years (10.84 [95% CI, 9.51-12.37] vs 7.91 [95% CI, 6.93-9.03]; aHR, 1.26; 95% CI, 1.10-1.44) and recurrent ICH (3.74 [95% CI, 3.01-4.66] vs 1.24 [95% CI, 0.89-1.73]; aHR, 2.63; 95% CI, 1.97-3.49) but not IS (1.45 [95% CI, 1.02-2.06] vs 1.77 [95% CI, 1.34-2.34]; aHR, 0.81; 95% CI, 0.60-1.10) or MI (0.42 [95% CI, 0.22-0.81] vs 0.64 [95% CI, 0.40-1.01]; aHR, 0.64; 95% CI, 0.38-1.09). Conclusions and Relevance: In this cohort study, spontaneous lobar ICH was associated with a higher rate of subsequent MACEs than nonlobar ICH, primarily due to a higher rate of recurrent ICH. This study highlights the importance of secondary ICH prevention strategies in patients with lobar ICH.

Association Between Statin Use and Intracerebral Hemorrhage Location: A Nested Case-Control Registry Study.

BACKGROUND AND OBJECTIVES: A causal relationship between statin use and intracerebral hemorrhage (ICH) is uncertain. We hypothesized that an association between long-term statin exposure and ICH risk might vary for different ICH locations. METHODS: We conducted this analysis using linked Danish nationwide registries. Within the Southern Denmark Region (population 1.2 million), we identified all first-ever cases of ICH between 2009 and 2018 in persons aged ≥55 years. Patients with medical record-verified diagnoses were classified as having a lobar or nonlobar ICH and matched for age, sex, and calendar year to general population controls. We used a nationwide prescription registry to ascertain prior statin and other medication use that we classified for recency, duration, and intensity. Using conditional logistic regression adjusted for potential confounders, we calculated adjusted ORs (aORs) and corresponding 95% CIs for the risk of lobar and nonlobar ICH. RESULTS: We identified 989 patients with lobar ICH (52.2% women, mean age 76.3 years) who we matched to 39,500 controls and 1,175 patients with nonlobar ICH (46.5% women, mean age 75.1 years) who we matched to 46,755 controls. Current statin use was associated with a lower risk of lobar (aOR 0.83; 95% CI, 0.70-0.98) and nonlobar ICH (aOR 0.84; 95% CI, 0.72-0.98). Longer duration of statin use was also associated with a lower risk of lobar (<1 year: aOR 0.89; 95% CI, 0.69-1.14; ≥1 year to <5 years aOR 0.89; 95% CI 0.73-1.09; ≥5 years aOR 0.67; 95% CI, 0.51-0.87; p for trend 0.040) and nonlobar ICH (<1 year: aOR 1.00; 95% CI, 0.80-1.25; ≥1 year to <5 years aOR 0.88; 95% CI 0.73-1.06; ≥5 years aOR 0.62; 95% CI, 0.48-0.80; p for trend <0.001). Estimates stratified by statin intensity were similar to the main estimates for low-medium intensity therapy (lobar aOR 0.82; nonlobar aOR 0.84); the association with high-intensity therapy was neutral. DISCUSSION: We found that statin use was associated with a lower risk of ICH, particularly with longer treatment duration. This association did not vary by hematoma location.

[Amphetamine-induced toxic encephalopathy].

In this case report, a 40-year-old woman presented with altered mentation, central facial palsy and hemiparesis. Acute CT scan showed several hypodense, rounded areas in both hemispheres. Urine toxicology tested positive for amphetamine. Subsequent cerebral MRI had hyperintense T2-weighted fluid-attenuated inverse recovery (FLAIR) lesions in both hemispheres, indicating demyelinating disease. A biopsy was made from one of the lesions. The final diagnosis was toxic encephalopathy.

Multiple Focal Brown Tumors (Osteitis Fibrosa Cystica) in a Renal Transplant Recipient.

Brown tumors (BTs) are manifestations of osteitis fibrosa cystica that develops due to increased osteoclast activity secondary to hyperparathyroidism (HPTH). The name comes from its characteristic brown color due to high hemosiderin level and hemorrhage surrounded by osteoclastic giant cells, fibrous tissue, and bone fragments. Presentation can be either unifocal or rarely multifocal. Misdiagnosis of BT compared to malignant giant cell tumor is not uncommon. Early diagnosis and intervention may prevent destructive bone changes. Treatment of BTs due to chronic renal failure should be aimed primarily at its prevention with phosphate binders, vitamin D (analogues), calcimimetics, and prolonged dialysis sessions. Parathyroidectomy can be the option in nonresponsive cases. In this report, we present an unusual case of multiple brown tumors in a 54-year-old female renal transplant patient involving the spine, jaw, and scapula, initially misdiagnosed as giant cell tumor. Five years later, the patient was diagnosed with BT because of the medical history, morphology, and negative p63 staining in combination with secondary/tertiary hyperparathyroidism. The patient subsequently underwent subtotal parathyroidectomy.