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.

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.

Validity of Simple Algorithms to Identify Recurrence of Intracerebral Hemorrhage in Two Danish Nationwide Registries.

PURPOSE: Danish registries could be an attractive resource for studies of recurrent intracerebral hemorrhage (re-ICH). We developed and validated algorithms to identify re-ICH in the Danish Stroke Registry (DSR) and the Danish National Patient Registry (DNPR). PATIENTS AND METHODS: Using multiple sources, we followed-up an inception cohort with verified first-ever spontaneous ICH (n = 2528) for their first re-ICH in 2009-2018 (study period). We used verified cases of re-ICH (n = 124) as the gold standard to assess the performance of register-based algorithms for identifying re-ICH. For each cohort member, we traced events of re-ICH (ICD-10-code I61) in the study period according to DSR and DNPR, respectively. For each registry, we tested algorithms with a blanking period (BP) - ie, a period immediately following the index ICH during which outcome events were ignored - of varying length (7 days-360 days). The algorithm with the shortest BP that returned a positive predictive value (PPV) of ≥80% was considered optimal. We also calculated negative predictive value (NPV), sensitivity, and specificity of each algorithm and [95% confidence intervals] for all proportions. RESULTS: The optimal algorithm for DSR (BP 30 days) had a PPV of 89.5% [82.2-94.0], NPV 98.8% [98.2-99.1], sensitivity 75.8% [67.6-82.5], and specificity 99.5% [99.2-99.7]. The optimal algorithm for DNPR (BP 120 days) had a PPV of 80.6% [71.7-87.2], NPV 98.1% [97.5-98.6], sensitivity 63.7% [55.0-71.6], and specificity 99.2% [98.8-99.5]. CONCLUSION: Simple algorithms accurately identified re-ICH in DSR and DNPR. Compared with DNPR, DSR achieved higher PPV and sensitivity with a shorter BP. The proposed algorithms could facilitate valid use of DSR and DNPR for studies of re-ICH.

Evolution of the gross tumour volume extent during radiotherapy for glioblastomas.

BACKGROUND AND PURPOSE: Tumour growth during radiotherapy may lead to geographical misses of the target volume. This study investigates the evolution of the tumour extent and evaluates the need for plan adaptation to ensure dose coverage of the target in glioblastoma patients. MATERIALS AND METHODS: The prospective study included 29 patients referred for 59.4 Gy in 33 fractions. Magnetic resonance imaging (MRI) was performed at the time of treatment planning, at fraction 10, 20, 30, and three weeks after the end of radiotherapy. The gross tumour volume (GTV) was defined as the T1w contrast-enhanced region plus the surgical cavity on each MRI set. The relative GTV volume and the maximum distance (Dmax) of the extent of the actual GTV outside the original GTV were measured. Based on the location of the actual GTV during radiotherapy and the original planned dose, a prospective clinical decision was made whether to adapt the treatment. RESULTS: Dose coverage of the GTV during radiotherapy was not compromised, and none of the radiotherapy plans was adapted. The median Dmax (range) was 5.7 (2.0-18.9) mm, 8.0 (2.0-27.4) mm, 8.0 (1.9-27.3) mm, and 8.9 (1.9-34.4) mm at fraction 10, 20, 30, and follow-up. The relative GTV volume and Dmax observed at fraction 10 were correlated with the values observed at follow-up (R = 0.74, p < 0.001 and R = 0.79, p < 0.001, respectively). CONCLUSION: Large variations in the GTV extent were observed, and changes often occurred early in the treatment. Plan adaptation for geographical misses was not performed in our cohort due to sufficient CTV margins.

[Seminal vesicle cyst with ipsilateral renal agenesis]. / Vesicula seminalis-cyste med ipsilateral nyreagenesi.

A formerly healthy 41-year-old male with monosymptomatic swelling of his left testicle was diagnosed with testicular cancer (seminoma). During staging of the cancer a computed tomography showed left renal agenesis and an 8 x 6 cm retrovesical space-occupying lesion in the left side of the pelvis. The lesion was interpreted as a group of enlarged lymph nodes, but PET/CT and MRI later demonstrated that it was a left seminal vesicle cyst. An association between congenital seminal vesicle cysts and ipsilateral renal agenesis is rare and can be explained by their common embryologic origin.

Acute gastric incarceration from thoracic herniation in pregnancy following laparoscopic antireflux surgery.

Diaphragmatic hernia is a rare complication in pregnancy which due to misdiagnosis or management delays may be life-threatening. We report a case of a woman in the third trimester of pregnancy who presented with sudden onset of severe epigastric and thoracic pain radiating to the back. Earlier in the index pregnancy, she had undergone laparoscopic antireflux surgery (ARS) for a hiatus hernia because of severe gastro-oesophageal reflux. Owing to increasing epigastric pain a CT scan was carried out which diagnosed wrap disruption with gastric herniation into the thoracic cavity and threatened incarceration. This is, to our knowledge, the first report of severe adverse outcome after ARS during pregnancy, with acute intrathoracic gastric herniation. We recommend the avoidance of ARS in pregnancy, and the need to advise women undergoing ARS of the postoperative risks if pregnancy occurs within a few years of ARS.