Ultrafast MRI using deep learning echoplanar imaging for a comprehensive assessment of acute ischemic stroke.

OBJECTIVES: Acute ischemic stroke (AIS) is an emergency requiring both fast and informative MR sequences. We aimed to assess the performance of an artificial intelligence-enhanced ultrafast (UF) protocol, compared to the reference protocol, in the AIS management. METHODS: We included patients admitted in the emergency department for suspected AIS. Each patient underwent a 3-T MR protocol, including reference acquisitions of T2-FLAIR, DWI, and SWI (duration: 7 min 54 s) and their accelerated multishot EPI counterparts for T2-FLAIR and T2*, complemented by a single-shot EPI DWI (duration: 1 min 54 s). Two blinded neuroradiologists reviewed each dataset, assessing DWI (detection, location, number of acute lesions), FLAIR (vascular hyperintensities, visibility of acute lesions), and SWI/T2* (hemorrhagic transformation, thrombus). We compared the agreement between the diagnoses obtained with both protocols using kappa coefficients. RESULTS: A total of 173 patients were included consecutively, of whom 80 with an AIS in DWI. We found an almost perfect agreement between the UF and reference protocols regarding the detection, distribution, number of AIS in DWI (κ = 0.98, 0.98, and 0.87 respectively), the presence of vascular hyperintensities, and the presence of a parenchymal hyperintensity in the AIS region in FLAIR (κ = 0.93 and 0.89 respectively). Agreement was substantial in T2*/SWI for thrombus detection, and fair for hemorrhagic transformation detection (κ = 0.64 and 0.38 respectively). Differential diagnoses were similarly detected by both protocols (κ = 1). CONCLUSIONS: Our AI-enhanced ultrafast MRI protocol allowed an effective detection and characterization of both AIS and differential diagnoses in less than 2 min. KEY POINTS: • The AI-enhanced ultrafast MRI protocol allowed an effective detection of acute stroke. • Characterization of stroke features with the UF protocol was equivalent to the reference sequences. • Differential diagnoses were detected similarly by the UF and reference protocols.

Limited benefit of systematic head CT for mild traumatic brain injury in patients under antithrombotic therapy.

BACKGROUND AND PURPOSE: Mild traumatic brain injury (mTBI) in patients on antiplatelet (AP), anticoagulant (AC) or direct oral anticoagulant (DOAC) medication has become a systematic indication for head CT. However, the over-risk and impact of the intracranial hemorrhages (IH) detected with CT in this population remain unclear and need to be assessed. MATERIALS AND METHODS: We prospectively assessed head CTs performed in adults taking AP/AC/DOAC referred after a mTBI to our Emergency Departments between September 2016 and January 2018. Frequency, type and severity of IH were described and frequency was analyzed as a function of treatment. RESULTS: 840 patients were prospectively included. 58.9% were treated with AP, 23.7% with AC, 11.7% with DOAC and 5.7% with a combination of antithrombotic agents. The rate of IH detected with head CT was 5.8% (n...=...49), of which 81.6% (n...=...40) and 18.4% (n...=...9) with minor and intermediate severity respectively. No patient required surgical care and no death occurred. No statistically significant difference was found in treatment distribution between patients with or without IH (p...=...0.98). Among the patients who discontinued their antithrombotic treatment after mTBI, three experienced thrombotic events during the hospitalization. CONCLUSIONS: Our results showed a low frequency and severity of IH in mTBI patients indifferently treated with AP, AC or DOAC, without secondary neurological deterioration, death or need of surgical care. Our study suggests the limited benefit of systematic CT head scan as a standard practice for the management of mTBI patients under antithrombotic therapy.

Perfusion of subchondral bone marrow in knee osteoarthritis: A dynamic contrast-enhanced magnetic resonance imaging preliminary study.

The role of inflammation in the pathogenesis of osteoarthritis is being given major interest, and inflammation is closely linked with vascularization. It was recently demonstrated that dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) could identify the subchondral bone marrow vascularization changes occurring in osteoarthritis in animals. These changes appeared before cartilage lesions were visible and were correlated with osteoarthritis severity. Thus the opportunity to obtain an objective assessment of bone vascularization in non-invasive conditions in humans might help better understanding osteoarthritis pathophysiology and finding new biomarkers. We hypothesized that, as in animals, DCE-MRI has the ability to identify subchondral bone marrow vascularization changes in human osteoarthritis. We performed knee MRI in 19 patients with advanced knee osteoarthritis. We assessed subchondral bone marrow vascularization in medial and lateral femorotibial compartments with DCE-MRI and graded osteoarthritis lesions on MR images. Statistical analysis assessed intra- and inter-observer agreement, compared DCE-MRI values between the different subchondral zones, and sought for an influence of age, sex, body mass index, and osteoarthritis garde on these values. The intra- and inter-observer agreement for DCE-MRI values were excellent. These values were significantly higher in the femorotibial compartment the most affected by osteoarthritis, both in femur and tibia (p<0.0001) and were significantly and positively correlated with cartilage lesions (p=0.02) and bone marrow oedema grade (p<0.0001) after adjustment. We concluded that, as in animals, subchondral bone marrow vascularization changes assessed with DCE-MRI were correlated with osteoarthritis severity in humans.

Traumatic avulsion of the superior extensor retinaculum of the ankle as a cause of subperiosteal haematoma of the distal fibula in children. A retrospective study of 7 cases.

OBJECTIVE: To describe a new sonographic feature for a traumatic lesion of the ankle in children. MATERIALS AND METHODS: We present a retrospective review of superior extensor retinaculum (SER) avulsions diagnosed by ultrasound (US) as a cause of subperiosteal haematoma (SPH) and periosteal apposition of the distal fibula in seven children (3 girls and 4 boys, mean age 13.4 years; age range 10-15 years) after an inversion trauma of the ankle. Two children were subsequently examined with magnetic resonance imaging (MRI). RESULTS: At the acute phases (6 children), US showed a hypoechoic collection with periosteal elevation at the fibular insertion of the SER. The fibular cortex and growth plate were unremarkable. The SPH was isolated in three cases and associated with an anterior talofibular ligament sprain in four. In two cases, MRI confirmed the SER periosteal avulsion and the integrity of the distal fibula. At the later phase (one child), US showed a periosteal apposition at the fibular insertion of the SER with hypoechoic thickening of the SER and power Doppler hyperaemia. CONCLUSION: This is the first sonographic description of SER avulsion as cause of SPH of the distal fibula in children. SPH in children should not be considered as pathognomonic of a Salter-Harris type 1 lesion of the distal fibula. Later, it may be responsible for persistent ankle pain. Therefore, SER may be systematically explored in children during US examination of the ankle after trauma.

Long-term growth rate of vestibular schwannoma in neurofibromatosis 2: A volumetric consideration.

OBJECTIVES/HYPOTHESIS: To determine the long-term growth rate of vestibular schwannoma (VS) in neurofibromatosis type 2 (NF2) patients based on volumetric measurements. STUDY DESIGN: Retrospective review. METHODS: We retrospectively reviewed magnetic resonance imaging (MRI) scans acquired from patients with NF2 from 1999 to 2013. Patients with an annual radiologic follow-up over at least 3 consecutive years were included. Volumetric VS growth was prospectively measured using a three-dimensional imaging workstation and through manual contouring of the lesion. Time to tumor progression was assessed according to the Response Evaluation in Neurofibromatosis and Schwannomatosis Tumor Measurement Group. RESULTS: Eighteen patients presenting with a total of 26 VSs were included. The mean age at diagnosis was 26.1 years (range, 7 to 49 years). One hundred five MRI scans were analyzed during a median radiological follow-up of 5.6 years (range, 3 to 12 years). The annual volume and diameter growth rates were respectively 218.3 mm(3) /yr (range, -10 to 1,250 mm(3) /yr) and 0.9 mm/yr (range, -0.5 to 4.5 mm/yr). Time to tumor progression was 3 years (median survival). There was a weak correlation between volumetric and linear measurements (P < .0001, linear regression, n = 26, r(2) = 0.58). Among the 26 VSs, 76.9% (20/26) showed progression (VS growth more than 20%), 19.2% were stable, and 3.9% (1/26) exhibited shrinkage (spontaneous regression of more than 20% of the initial volume). CONCLUSIONS: This study helps to assess the long-term growth profile of VS in a population of NF2 patients with untreated VS. These data could help to better acknowledge VS natural growth history. LEVEL OF EVIDENCE: 4 Laryngoscope, 126:2358-2362, 2016.