Self-supervised enhanced thyroid nodule detection in ultrasound examination video sequences with multi-perspective evaluation.

Objective.Ultrasound is the most commonly used examination for the detection and identification of thyroid nodules. Since manual detection is time-consuming and subjective, attempts to introduce machine learning into this process are ongoing. However, the performance of these methods is limited by the low signal-to-noise ratio and tissue contrast of ultrasound images. To address these challenges, we extend thyroid nodule detection from image-based to video-based using the temporal context information in ultrasound videos.Approach.We propose a video-based deep learning model with adjacent frame perception (AFP) for accurate and real-time thyroid nodule detection. Compared to image-based methods, AFP can aggregate semantically similar contextual features in the video. Furthermore, considering the cost of medical image annotation for video-based models, a patch scale self-supervised model (PASS) is proposed. PASS is trained on unlabeled datasets to improve the performance of the AFP model without additional labelling costs.Main results.The PASS model is trained by 92 videos containing 23 773 frames, of which 60 annotated videos containing 16 694 frames were used to train and evaluate the AFP model. The evaluation is performed from the video, frame, nodule, and localization perspectives. In the evaluation of the localization perspective, we used the average precision metric with the intersection-over-union threshold set to 50% (AP@50), which is the area under the smoothed Precision-Recall curve. Our proposed AFP improved AP@50 from 0.256 to 0.390, while the PASS-enhanced AFP further improved the AP@50 to 0.425. AFP and PASS also improve the performance in the valuations of other perspectives based on the localization results.Significance.Our video-based model can mitigate the effects of low signal-to-noise ratio and tissue contrast in ultrasound images and enable the accurate detection of thyroid nodules in real-time. The evaluation from multiple perspectives of the ablation experiments demonstrates the effectiveness of our proposed AFP and PASS models.

CT-TEE Image Registration for Surgical Navigation of Congenital Heart Disease Based on a Cycle Adversarial Network.

Transesophageal echocardiography (TEE) has become an essential tool in interventional cardiologist's daily toolbox which allows a continuous visualization of the movement of the visceral organ without trauma and the observation of the heartbeat in real time, due to the sensor's location at the esophagus directly behind the heart and it becomes useful for navigation during the surgery. However, TEE images provide very limited data on clear anatomically cardiac structures. Instead, computed tomography (CT) images can provide anatomical information of cardiac structures, which can be used as guidance to interpret TEE images. In this paper, we will focus on how to transfer the anatomical information from CT images to TEE images via registration, which is quite challenging but significant to physicians and clinicians due to the extreme morphological deformation and different appearance between CT and TEE images of the same person. In this paper, we proposed a learning-based method to register cardiac CT images to TEE images. In the proposed method, to reduce the deformation between two images, we introduce the Cycle Generative Adversarial Network (CycleGAN) into our method simulating TEE-like images from CT images to reduce their appearance gap. Then, we perform nongrid registration to align TEE-like images with TEE images. The experimental results on both children' and adults' CT and TEE images show that our proposed method outperforms other compared methods. It is quite noted that reducing the appearance gap between CT and TEE images can benefit physicians and clinicians to get the anatomical information of ROIs in TEE images during the cardiac surgical operation.

Astragaloside IV inhibits progression of glioma via blocking MAPK/ERK signaling pathway.

Glioma is one of the most common primary brain tumors in adults with a high mortality rate and relapse rate. Thus, finding better effective approaches to treat glioma has become very urgent. Astragaloside IV (AS-IV), the major active triterpenoid in Radix Astragali, has shown anti-tumorigenic properties in certain cancers. However, its role in glioma remains unclear. Here, we studied the effects of AS-IV on glioma in vitro and in vivo, and explored the underlying mechanisms. Our results revealed that AS-IV dose-dependently inhibited the proliferation of U251 cells in vitro and attenuated tumor growth in vivo. In addition, the migration and invasion ability of U251 cell has been suppressed in presence of AS-IV. The levels of proliferating cell nuclear antigen (PCNA), Ki67, matrix metallopeptidase (MMP) -2, MMP-9 and vascular endothelial growth factor (VEGF) were decreased significantly by the treatment of different concentrations AS-IV. Furthermore, AS-IV also significantly weakened the activation of Mitogen-activated protein kinase/Extracellular regulated protein kinase (MAPK/ERK) signaling pathway in vitro and in vivo. Taken together our study has identified a novel function of AS-IV and provided a molecular basis for AS-IV potential applications in the treatment of glioma and other cancers.

MicroRNA-181 inhibits glioma cell proliferation by targeting cyclin B1.

Small non­coding RNAs from the microRNA family (miRs) are important elements in the posttranscriptional control of gene expression. miRs are known to regulate numerous cellular processes and are of crucial importance during development and in pathological conditions, including tumor initiation and progression. In the present study, the expression level of miR­181 was reduced in glioma tissues compared with the adjacent normal tissues. The enforced expression of miR­181 was able to inhibit cell proliferation in U251 and SHG­44 cells, while antisense miR­181 oligonucleotides (antisense miR­181) enhanced cell proliferation. At the molecular level, these results further revealed that the expression of cyclin B1, a positive cell­cycle regulator, was negatively regulated by miR­181. Therefore, the data reported in the present study demonstrates that miR­181 is an important regulator in glioma. These results may contribute to improving the understanding of the key misregulated miRNAs in glioma.

Relationships between PTEN gene mutations and prognosis in glioma: a meta-analysis.

We conducted a meta-analysis in order to investigate the relationships between PTEN gene mutations and the prognosis in glioma. The following electronic databases were searched for relevant articles without any language restrictions: Web of Science (1945 ~ 2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966 ~ 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), and the Chinese Biomedical Database (CBM) (1982 ~ 2013). Meta-analyses were conducted using the STATA software (Version 12.0, Stata Corporation, College Station, Texas USA). Hazard ratio (HR) with its corresponding 95 % confidence interval (95%CI) was calculated. Six independent cohort studies with a total of 357 glioma patients met our inclusion criteria. Our meta-analysis results indicated that glioma patients with PTEN gene mutations exhibited a significantly shorter overall survival (OS) than those without PTEN gene mutations (HR = 3.66, 95%CI = 2.02 ~ 5.30, P < 0.001). Ethnicity-stratified subgroup analysis demonstrated that PTEN gene mutations were closely linked to poor prognosis in glioma among Americans (HR = 3.72, 95%CI = 1.72 ~ 5.73, P < 0.001), while similar correlations were not observed among populations in Sweden, Italy, and Malaysia (all P > 0.05). Our meta-analysis provides direct and strong evidences for the speculation of PTEN gene mutations' correlation with poor prognosis of glioma patients.

Studies on the operative outcomes and mechanisms of microvascular decompression in treating typical and atypical trigeminal neuralgia.

OBJECTIVE: To evaluate the operative outcomes and mechanisms of microvascular decompression in treating typical and atypical trigeminal neuralgia. METHODS: A group of 45 patients with typical trigeminal neuralgia and 17 patients with atypical trigeminal neuralgia treated by micro-vascular decompression from 2000 to 2002 were reviewed, including their clinical presentations, operative findings, and outcomes. RESULTS: Of 45 patients with typical trigeminal neuralgia, the mean duration was 3.1 years, and the mean age of pain onset was 60.3 years. Single trigeminal division was involved in 20 patients (44.4%), and 2 or 3 divisions were involved in the other 25 patients (55.6%). During the operation, artery compression was found in 39 patients (86.7%), and the combined artery and venous compression was found in 6 patients (13.3%). Postoperatively, complete pain relief was achieved in 44 patients (97.8%), and significant pain relief was achieved in 1 patient (2.2%). As for 17 patients with atypical trigeminal neuralgia, the mean duration and the mean age of pain onset was 8.7 years and 55.5 years, respectively. Two or 3 trigeminal divisions were involved in all of these patients. During operation, artery compression occurred in 10 patients (58.8%), and the combined artery and venous compression was found in 7 patients (41.2%). Postoperatively, complete pain relief was achieved in 5 patients (29.4%), and partial pain relief was achieved in 10 patients (58.8%), and 2 patients showed no response to microvascular decompression. CONCLUSIONS: The operative outcome of microvascular decompression in patients with typical trigeminal neuralgia was better than that of patients with atypical trigeminal neuralgia, which perhaps related to short duration, late onset of pain, limited distribution, artery compression, and complete operative decompression.

Trigeminal neuralgia: what are the important factors for good operative outcomes with microvascular decompression.

BACKGROUND: Microvascular decompression has been widely used as the first choice in treating trigeminal neuralgia, but in a few patients, facial pain cannot be effectively controlled by microvascular decompression. We sought to clarify the important factors for good operative outcomes. METHODS: We reviewed 62 patients with trigeminal neuralgia treated by microvascular decompression during the period 2000 through 2002, including clinical presentation, operative findings, techniques, and outcomes. Neurovascular conflicts were divided into single contact, contact and indentation, single adhesion, adhesion and indentation, and trigeminal nerve atrophy. Operative outcomes were graded into immediate postoperative complete pain relief (excellent), delayed postoperative complete pain relief (better), significant pain relief (good), and no response to microvascular decompression (poor). RESULTS: All patients' presentations were typical at the time of pain onset, but the symptom in 17 patients changed to atypical before surgery. During operation, single contact and single adhesion was found in 14 patients and 15 patients, respectively; contact or adhesion in combination with indentation was found in 7 patients and 18 patients, respectively; atrophy occurred in 8 patients. Postoperatively, immediate and delayed complete pain relief was achieved in 32 (51.6%) patients and 17 (27.4%) patients, respectively; 11(17.7%) patients got significant pain relief; and 2 patients showed no response. The overall rate of complete pain relief in patients with shorter duration, typical presentation, artery compression and complete decompression was higher than that in patients with longer duration, atypical presentation, venous compression, and incomplete decompression. CONCLUSIONS: Shorter duration, typical presentation, single artery compression, and complete decompression are the positive factors for better operative outcomes with microvascular decompression. Worse outcomes are usually related to venous compression, longer duration, and atypical presentation.

Neurotization of oculomotor, trochlear and abducent nerves in skull base surgery.

OBJECTIVE: To anatomically reconstruct the oculomotor nerve, trochlear nerve, and abducent nerve by skull base surgery. METHODS: Seventeen cranial nerves (three oculomotor nerves, eight trochlear nerves and six abducent nerves) were injured and anatomically reconstructed in thirteen skull base operations during a period from 1994 to 2000. Repair techniques included end-to-end neurosuture or fibrin glue adhesion, graft neurosuture or fibrin glue adhesion. The relationships between repair techniques and functional recovery and the related factors were analyzed. RESULTS: Functional recovery began from 3 to 8 months after surgery. During a follow-up period of 4 months to 6 years, complete recovery of function was observed in 6 trochlear nerves (75%) and 4 abducent nerves (67%), while partial functional recovery was observed in the other cranial nerves including 2 trochlear nerves, 2 abducent nerves, and 3 oculomotor nerves. CONCLUSIONS: Complete or partial functional recovery could be expected after anatomical neurotization of an injured oculomotor, trochlear or abducent nerve. Our study demonstrated that, in terms of functional recovery, trochlear and abducent nerves are more responsive than oculomotor nerves, and that end-to-end reconstruction is more efficient than graft reconstruction. These results encourage us to perform reconstruction for a separated cranial nerve as often as possible during skull base surgery.