Masked Vision and Language Pre-training with Unimodal and Multimodal Contrastive Losses for Medical Visual Question Answering

Medical visual question answering (VQA) is a challenging task that requires answering clinical questions of a given medical image, by taking consider of both visual and language information. However, due to the small scale of training data for medical VQA, pre-training fine-tuning paradigms have been a commonly used solution to improve model generalization performance. In this paper, we present a novel self-supervised approach that learns unimodal and multimodal feature representations of input images and text using medical image caption datasets, by leveraging both unimodal and multimodal contrastive losses, along with masked language modeling and image text matching as pretraining objectives. The pre-trained model is then transferred to downstream medical VQA tasks. The proposed approach achieves state-of-the-art (SOTA) performance on three publicly available medical VQA datasets with significant accuracy improvements of 2.2%, 14.7%, and 1.7% respectively. Besides, we conduct a comprehensive analysis to validate the effectiveness of different components of the approach and study different pre-training settings. Our codes and models are available at https://github.com/pengfeiliHEU/MUMC.Comment: accepted by MICCAI202

Cerebral Falx Mature Teratoma with Rare Imaging in an Adult

Intracranial mature teratoma is a rare lesion in adults. Despite several intracranial mature teratomas had been reported not to be located at the midline region, no one was found to be within cerebral falx. Herein, we reported a 37-year-old female patient with an intracranial mature teratoma confined within frontal cerebral falx. Her main complaint was intermitted headache, which could not be relieved recently by taking painkiller. Excepting for mild papilledema, we did not find positive neurological signs on physical examination. CT scanning showed it was a round homogenously hypodense lesion with hyperdense signal at its rim. MRI revealed the lesion was 3.5cm×3.6cm×4.5cm in volume, with uniformed hypointensity on T1WI, hyperintensity on T2WI and enhancement in the capsule. It was totally removed via inter-hemispheric approach, and we found the lesion was confined within the frontal cerebral falx. Postoperatively, it was proved histologically to be a mature teratoma. At three years of fellow up, neither neurological deficits nor recurrent sings on MRI was found. To our best knowledge, this is the first case of intracranial mature teratoma within cerebral falx

Self-supervised vision-language pretraining for Medical visual question answering

Medical image visual question answering (VQA) is a task to answer clinical questions, given a radiographic image, which is a challenging problem that requires a model to integrate both vision and language information. To solve medical VQA problems with a limited number of training data, pretrain-finetune paradigm is widely used to improve the model generalization. In this paper, we propose a self-supervised method that applies Masked image modeling, Masked language modeling, Image text matching and Image text alignment via contrastive learning (M2I2) for pretraining on medical image caption dataset, and finetunes to downstream medical VQA tasks. The proposed method achieves state-of-the-art performance on all the three public medical VQA datasets. Our codes and models are available at https://github.com/pengfeiliHEU/M2I2.Comment: 5 pages, 3 figure

Strain-induced semiconductor to metal transition in MA2Z4 bilayers

Very recently, a new type of two-dimensional layered material MoSi2N4 has been fabricated, which is semiconducting with weak interlayer interaction, high strength, and excellent stability. We systematically investigate theoretically the effect of vertical strain on the electronic structure of MA2Z4 (M=Ti/Cr/Mo, A=Si, Z=N/P) bilayers. Taking bilayer MoSi2N4 as an example, our first principle calculations show that its indirect band gap decreases monotonically as the vertical compressive strain increases. Under a critical strain around 22%, it undergoes a transition from semiconductor to metal. We attribute this to the opposite energy shift of states in different layers, which originates from the built-in electric field induced by the asymmetric charge transfer between two inner sublayers near the interface. Similar semiconductor to metal transitions are observed in other strained MA2Z4 bilayers, and the estimated critical pressures to realize such transitions are within the same order as semiconducting transition metal dichalcogenides. The semiconductor to metal transitions observed in the family of MA2Z4 bilayers present interesting possibilities for strain-induced engineering of their electronic properties

(1R*,2R*)-1-(7-Bromo-3-methoxy­naphthalen-2-yl)-4-(dimethyl­amino)-2-(naphthalen-1-yl)-1-phenyl­butan-2-ol

In the crystal structure of the title compound, C33H32BrNO2, the naphthalene ring system and the benzene ring are oriented at dihedral angles of 82.24 (4) and 79.53 (4)°, respectively, to the quinoline ring system. An intra­molecular O—H⋯N hydrogen bond occurs between the hydr­oxy H atom and the amine N atom

(R)-1-[(S)-(3-Cyano­thio­morpholino)carbon­yl]-2-methyl­propyl­aminium chloride dihydrate

In the title compound, C10H18N3OS+·Cl−·2H2O, the three C atoms of the isopropyl group are disordered and were refined using a split-site mode [occupancy ratio 0.53 (3):0.47 (3)]. In the crystal, the cations, anions and water mol­ecules are connected via O—H⋯O, O—H⋯Cl, N—H⋯Cl and N—H⋯O hydrogen bonding

Duszność spowodowana gruźliczakami powstającymi w rdzeniu przedłużonym w czasie leczenia gruźliczego zapalenia opon mózgowo-rdzeniowych

Formation of tuberculoma is a rare response of neurotuberculosis in patients regularly and adequately treated with anti-tuberculous drugs. We report a 13-year-old girl with two tuberculomas which formed in the dorsal part of the medulla oblongata during chemotherapy for tuberculous meningitis. The tuberculomas were both removed via a suboccipital midline approach and were demonstrated by pathological findings but the girl died of cardiac arrest that was thought to be caused by postoperative medulla oblongata oedema. In combination with a literature review, we discuss the clinical features and treatment options of brainstem tuberculomas.Tworzenie się gruźliczaka jest rzadką reakcją w przebiegu właściwie leczonej gruźlicy układu nerwowego. W pracy autorzy opisują przypadek 13-letniej dziewczynki z dwoma gruźliczakami, które utworzyły się w grzbietowej części rdzenia przedłużonego w czasie farmakologicznego leczenia gruźliczego zapalenia opon mózgowo-rdzeniowych. Oba gruźliczaki usunięto z dostępu podpotylicznego w linii środkowej i potwierdzono ich rozpoznanie w badaniu histopatologicznym, ale pacjentka zmarła w wyniku zatrzymania krążenia, przypuszczalnie wskutek pooperacyjnego obrzęku rdzenia przedłużonego. Na podstawie przedstawionego przypadku i przeglądu piśmiennictwa omówiono objawy kliniczne i możliwości leczenia gruźliczaków pnia mózgu