Deep Neural Network Regression for Automated Retinal Layer Segmentation in Optical Coherence Tomography Images

Segmenting the retinal layers in optical coherence tomography (OCT) images helps to quantify the layer information in early diagnosis of retinal diseases, which are the main cause of permanent blindness. Thus, the segmentation process plays a critical role in preventing vision impairment. However, because there is a lack of practical automated techniques, expert ophthalmologists still have to manually segment the retinal layers. In this study, we propose an automated segmentation method for OCT images based on a feature-learning regression network without human bias. The proposed deep neural network regression takes the intensity, gradient, and adaptive normalized intensity score (ANIS) of an image segment as features for learning, and then predicts the corresponding retinal boundary pixel. Reformulating the segmentation as a regression problem obviates the need for a huge dataset and reduces the complexity significantly, as shown in the analysis of computational complexity given here. In addition, assisted by ANIS, the method operates robustly on OCT images containing intensity variances, low-contrast regions, speckle noise, and blood vessels, yet remains accurate and time-efficient. In evaluation of the method conducted using 114 images, the processing time was approximately 10.596 s per image for identifying eight boundaries, and the training phase for each boundary line took only 30 s. Further, the Dice similarity coefficient used for assessing accuracy gave a computed value of approximately 0.966. The absolute pixel distance of manual and automatic segmentation using the proposed scheme was 0.612, which is less than a one-pixel difference, on average.

A Biliary Tract-Specific Near-Infrared Fluorescent Dye for Image-Guided Hepatobiliary Surgery

Despite advances, visual inspection, palpation, and intraoperative ultrasound remain the most utilized tools during surgery today. A particularly challenging issue is the identification of the biliary system due to its complex architecture partially embedded within the liver. Fluorescence guided surgical interventions, particularly using near-infrared (NIR) wavelengths, are an emerging approach for the real-time assessment of the hepatobiliary system. However, existing fluorophores, such as the FDA-approved indocyanine green (ICG), have significant limitations for rapid and selective visualization of bile duct anatomy. Here we report a novel NIR fluorophore, BL (Bile Label)-760, which is exclusively metabolized by the liver providing high signal in the biliary system shortly after intravenous administration. This molecule was identified by first screening a small set of known heptamethine cyanines including clinically utilized agents. After finding that none of these were well-suited, we then designed and tested a small series of novel dyes within a prescribed polarity range. We validated the molecule that emerged from these efforts, BL-760, through animal studies using both rodent and swine models employing a clinically applicable imaging system. In contrast to ICG, BL-760 fluorescence revealed a high target-to-background ratio (TBR) of the cystic duct relative to liver parenchyma 5 min after intravenous injection. During hepatic resection surgery, intrahepatic ducts were clearly highlighted, and bile leakage was easily detected. In conclusion, BL-760 has highly promising properties for intraoperative navigation during hepatobiliary surgery.

Abstract P3-12-12: Impact of regional nodal irradiation for breast cancer patients with supraclavicular and/or internal mammary lymph node involvement: A multicenter, retrospective study (KROG 16-14)

Purpose: To evaluate the treatment outcomes of radiotherapy (RT) for breast cancer with ipsilateral supraclavicular (SCL) and/or internal mammary (IMN) lymph node involvement.

Methods: A total of 353 patients from 11 institutions were included. One hundred and thirty-six patients had SCL involvement, 148 had IMN involvement, and 69 had both. All patients received neoadjvant systemic therapy followed by breast conserving surgery or mastectomy, and postoperative RT to whole breast/chest wall. As for regional lymph node irradiation, SCL RT was given to 344 patients, and IMN RT to 236 patients. The median RT dose was 50.4 Gy.

Results: The median follow-up duration was 61 months (range, 7-173). In-field progression was present in SCL (n=20) and/or IMN (n=7). The 5-year disease-free survival (DFS) and overall survival rates were 57.8% and 75.1%, respectively. On multivariate analysis, both SCL/IMN involvement, number of axillary lymph node ≥4, triple negative subtype, and mastectomy were significant adverse prognosticators for DFS (p = 0.022, 0.001, 0.001, and 0.004, respectively). Regarding the impact of regional nodal irradiation, SCL RT dose ≥54 Gy was not associated with DFS (5-yr rate, 52.9% vs. 50.9%, p = 0.696) in SCL-involved patients, and the receipt of IMN RT was not associated with DFS (5-yr rate, 56.1% vs. 78.1%, p = 0.099) in IMN-involved patients.

Conclusion: Neoadjuvant chemotherapy followed by surgery and postoperative RT achieved an acceptable in-field regional control rate in patients with SCL and/or IMN involvement. However, a higher RT dose to SCL or IMN RT was not associated with the improved DFS in these patients.

Citation Format: Kim K, Jeong Y, Shin KH, Kim JH, Ahn SD, Kim SS, Suh C-O, Kim YB, Choi DH, Park W, Cha J, Chun M, Lee DS, Lee SY, Kim JH, Park HJ. Impact of regional nodal irradiation for breast cancer patients with supraclavicular and/or internal mammary lymph node involvement: A multicenter, retrospective study (KROG 16-14) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-12-12.

Dual-display laparoscopic laser speckle contrast imaging for real-time surgical assistance

Laser speckle contrast imaging (LSCI) utilizes the speckle pattern of a laser to determine the blood flow in tissues. The current approaches for its use in a clinical setting require a camera system with a laser source on a separate optical axis making it unsuitable for minimally invasive surgery (MIS). With blood flow visualization, bowel viability, for example, can be determined. Thus, LSCI can be a valuable tool in gastrointestinal surgery. In this work, we develop the first-of-its-kind dual-display laparoscopic vision system integrating LSCI with a commercially available 10mm rigid laparoscope where the laser has the same optical axis as the laparoscope. Designed for MIS, our system permits standard color RGB, label-free vasculature imaging, and fused display modes. A graphics processing unit accelerated algorithm enables the real-time display of three different modes at the surgical site. We demonstrate the capability of our system for imaging relative flow rates in a microfluidic phantom with channels as small as 200 μm at a working distance of 1-5 cm from the laparoscope tip to the phantom surface. Using our system, we reveal early changes in bowel perfusion, which are invisible to standard color vision using a rat bowel occlusion model. Furthermore, we apply our system for the first time for imaging intestinal vasculature during MIS in a swine.

Real-time, label-free, intraoperative visualization of peripheral nerves and micro-vasculatures using multimodal optical imaging techniques

Accurate, real-time identification and display of critical anatomic structures, such as the nerve and vasculature structures, are critical for reducing complications and improving surgical outcomes. Human vision is frequently limited in clearly distinguishing and contrasting these structures. We present a novel imaging system, which enables noninvasive visualization of critical anatomic structures during surgical dissection. Peripheral nerves are visualized by a snapshot polarimetry that calculates the anisotropic optical properties. Vascular structures, both venous and arterial, are identified and monitored in real-time using a near-infrared laser-speckle-contrast imaging. We evaluate the system by performing in vivo animal studies with qualitative comparison by contrast-agent-aided fluorescence imaging.

A chemically stable fluorescent marker of the ureter

Surgical methods guided by exogenous fluorescent markers have the potential to define tissue types in real time. Small molecule dyes with efficient and selective renal clearance could enable visualization of the ureter during surgical procedures involving the abdomen and pelvis. These studies report the design and synthesis of a water soluble, net neutral C4'-O-alkyl heptamethine cyanine, Ureter-Label (UL)-766, with excellent properties for ureter visualization. This compound is accessed through a concise synthetic sequence involving an N- to O-transposition reaction that provides other inaccessible C4'-O-alkyl heptamethine cyanines. Unlike molecules containing a C4'-O-aryl substituent, which have also been used for ureter visualization, UL-766 is not reactive towards glutathione and the cellular proteome. In addition, rat models of abdominal surgery reveal that UL-766 undergoes efficient and nearly exclusive renal clearance in vivo. In total, this molecule represents a promising candidate for visualizing the ureter during a variety of surgical interventions.

Melanoma of the Sinonasal Tract: Value of a Septate Pattern on Precontrast T1-Weighted MR Imaging

BACKGROUND AND PURPOSE

Various tumors of the sinonasal tract can exhibit high signal intensity on T1WI. The purpose of this study was to determine the value of a septate pattern on precontrast T1WI for diagnosing sinonasal melanoma.

MATERIALS AND METHODS

Retrospectively, 3 observers independently reviewed MR images of 31 histologically proved sinonasal melanomas with special attention to the presence or absence of a septate pattern on precontrast T1WI, defined as alternating hyperintense and hypointense striations on precontrast T1WI. For comparison, we evaluated the prevalence of a septate pattern on precontrast T1WI in 106 nonmelanomatous sinonasal malignant tumors with 16 different histologic types. We also tried to identify the histopathologic features responsible for the septate pattern on precontrast T1WI.

RESULTS

Twenty-seven (87.1%) of 31 sinonasal melanomas showed hyperintense foci on T1WI, among which a septate pattern on precontrast T1WI was seen in 23 (74.2%), while 22 (20.8%) of 106 nonmelanomatous malignant tumors demonstrated hyperintense foci on T1WI, among which only 3 (2.8%) showed a septate pattern on precontrast T1WI. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of a septate pattern on precontrast T1WI for the diagnosis of sinonasal melanoma were 74%, 97%, 88%, 93%, and 92%, respectively. Although limited due to the retrospective nature, 4 of 23 histologically reviewed sinonasal melanomas revealed an uneven distribution of melanin with alternating melanin and fibrous bands within the tumors.

CONCLUSIONS

A septate pattern on precontrast T1WI might be an adjunctive imaging finding for the diagnosis of sinonasal melanoma. This might be attributed histologically to an uneven distribution of melanin and hemorrhage within the tumors.

[Study of epidemic area on Tsutsugamushi disease in Taizhou from 2013 to 2014]

Objective: To study the epidemiological characteristics of tsutsugamushi disease, and to confirm the existence of the disease's epidemic foci in Taizhou. Methods: From 2013 to 2014, Dongxing town hospital and Xingqiao town hospital were selected as specimen collection sites in Jingjiang city. Blood samples (5 ml) were collected from 40 patients with acute tsutsugamushi disease. A total of 59 rodents were captured with cage night method in the survey sites at 5, 7, 9, 10, and 11 months in 2013, from which, the spleen, liver, and kidney specimens were selected. Chigger mites were captured by small blackboard method and from the ears of the captured rodents. A total of 226 small blackboards were laid, 27 mites were captured, and the samples were grounded into suspension. Nested-polymerase chain reaction and cell and tissue culture techniques were used to test the specimen from the probable patients, host animals and chigger mites. Results: Among the 40 acute tsutsugamushi disease blood samples, 29 were found to meet the test requirements, 17 were positive for orientia tsutsugamushi nucleic acid with 59% of the positive rate, and 1 stran orientia tsutsugamushi was isolated. 59 rats were captured and the density of mice was 5.5%. Among them, there were 26 Mus musculus (2.4%), 18 Rattus flavipectus (1.7%) and 15 Smelly shrew (density 1.4%). 1 Smelly shrew was tested positive for orientia tsutsugamushi nucleic acid, and the negative results were found in the other rodent specimens. 27 Chigge mites were collected by small blackboard method and the density of mites was 0.12 for each blackboard, among which 3 larvae and 24 nymphs were found. 33 Chigger mites were collected from the ears of 3 Smelly shrew, and the density of the mite was 11 per mouse. All the captured Chigger mites were identified as Leptotrombidium scutellare and 1 group of specimens of Chigger mites from the external environment were positive for orientia tsutsugamushi nucleic acid. Conclusion: There was a high density of mice in the epidemic area from May to November and the species of the chigger mites were Chigger mites in Taizhou. The nucleic acid of the oriental tsutsugamushi was detected in the patients with acute scrub typhus, rodents and vectors. According to the above-mentioned results, it was considered that the scrub typhus epidemic area of Taizhou city has the natural foci of scrub typhus.

Alterations in amygdala-prefrontal circuits in infants exposed to prenatal maternal depression

Prenatal exposure to maternal depression is common and puts offspring at risk for developing a range of neuropsychiatric disorders. Despite its prevalence and adverse associations, neurobiological processes by which prenatal maternal depression (PMD) confers risk remain poorly understood. Maternal mood and fetal behavior were assessed between 34 and 37 gestational weeks. Using resting-state functional magnetic resonance imaging (fMRI) and diffusion MRI, we examined functional and structural connectivity within amygdala-prefrontal circuits in 64 infants (mean age=5.8±1.7 weeks) with (n=20) and without (n=44) in utero exposure to PMD. Resting fMRI and diffusion MRI both indicated atypical amygdala-prefrontal connectivity in PMD-exposed infants: Resting fMRI indicated increased inverse, or negative, functional connectivity between the amygdala and the dorsal prefrontal cortex (PFC), bilaterally, and diffusion MRI indicated decreased structural connectivity between the right amygdala and the right ventral PFC. Spectral dynamic causal modeling supported these findings suggesting altered amygdala-PFC effective (or directed) connectivity in PMD-exposed infants. Last, path analyses supported a mechanistic account relating PMD to a third-trimester fetal behavior: PMD alters amygdala-PFC connectivity, which in turn, is associated with an increase in fetal heart rate reactivity to in utero perturbation. These data suggest that the maturation and coordination of central and peripheral physiology are altered by prenatal exposure to maternal depression. To the best of our knowledge, this is the first study to directly associate infant MRI measures with a behavior-fetal heart rate response, and supports hypotheses that PMD-associated variations in the development of amygdala-PFC circuits are relevant for future neurobehavioral maturation.

Differentiation of Hemangioblastoma from Metastatic Brain Tumor using Dynamic Contrast-enhanced MR Imaging

PURPOSE

The aim of this study was to differentiate hemangioblastomas from metastatic brain tumors using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and compare the diagnostic performances with diffusion-weighted imaging (DWI) and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI).

METHODS

We retrospectively reviewed 7 patients with hemangioblastoma and 15 patients with metastatic adenocarcinoma with magnetic resonance imaging (MRI) including DWI, DSC-MRI, and DCE-MRI. Apparent diffusion coefficient (ADC), relative cerebral blood volume (rCBV), and DCE-MRI parameters (K ^trans, k _ep, v _e, and v _p) were compared between the two groups. The diagnostic performance of each parameter was evaluated with receiver operating characteristic (ROC) curve analysis.

RESULTS

v _p, k _ep, and rCBV were significantly different between patients with hemangioblastoma and those with metastatic brain tumor (p < 0.001, p = 0.005, and p = 0.017, respectively). A v _p cutoff value of 0.012 and a rCBV cutoff value of 8.0 showed the highest accuracy for differentiating hemangioblastoma from metastasis. The area under the ROC curve for v _p and rCBV was 0.99 and 0.89, respectively. A v _p > 0.012 showed 100 % sensitivity, 93.3 % specificity, and 95.5 % accuracy and a rCBV > 8.0 showed 85.7 % sensitivity, 93.3 % specificity, and 90.9 % accuracy for differentiating hemangioblastoma from metastatic brain tumor.

CONCLUSION

DCE-MRI was useful for differentiating hemangioblastoma from metastatic brain tumor.