Repeatability and reproducibility of deep-learning-based liver volume and Couinaud segment volume measurement tool

Purpose Volumetric and health assessment of the liver is crucial to avoid poor post-operative outcomes following liver resection surgery. No current methods allow for concurrent and accurate measurement of both Couinaud segmental volumes for future liver remnant estimation and liver health using non-invasive imaging. In this study, we demonstrate the accuracy and precision of segmental volume measurements using new medical software, Hepatica™. Methods MRI scans from 48 volunteers from three previous studies were used in this analysis. Measurements obtained from Hepatica™ were compared with OsiriX. Time required per case with each software was also compared. The performance of technicians and experienced radiologists as well as the repeatability and reproducibility were compared using Bland–Altman plots and limits of agreement. Results High levels of agreement and lower inter-operator variability for liver volume measurements were shown between Hepatica™ and existing methods for liver volumetry (mean Dice score 0.947 ± 0.010). A high consistency between technicians and experienced radiologists using the device for volumetry was shown (± 3.5% of total liver volume) as well as low inter-observer and intra-observer variability. Tight limits of agreement were shown between repeated Couinaud segment volume (+ 3.4% of whole liver), segmental liver fibroinflammation and segmental liver fat measurements in the same participant on the same scanner and between different scanners. An underestimation of whole-liver volume was observed between three non-reference scanners. Conclusion Hepatica™ produces accurate and precise whole-liver and Couinaud segment volume and liver tissue characteristic measurements. Measurements are consistent between trained technicians and experienced radiologists. Graphic abstract

Assessing watershed hydrological response to climate change based on signature indices

Due to the fact that one of the important ways of describing the performance of basins is to use the hydrological signatures, the present study is to investigate the effects of climate change using the hydrological signatures in Azarshahr Chay basin, Iran. To this end, Canadian Earth system model (CanESM2) is first used to predict future climate change (2030–2059) under two Representative Concentration Pathways (RCP2.6 and RCP8.5). Six signature indices were extracted from flow duration curve (FDC) as follows: runoff ratio (RR), high-segment volume (FHV), low-segment volume (FLV), mid-segment slope (FMS), mid-range flow (FMM), and maximum peak discharge (DiffMaxPeak). These signature indices act as sorts of fingerprints representing differences in the hydrological behavior of the basin. The results indicate that the most significant changes in the future hydrological response are related to the FHV and FLV and FMS indices. The BiasFHV index indicates an increase in high discharge rates under RCP8.5 scenario, compared to the baseline period and the RCP2.6 scenario, as well. The mean annual discharge rate, however, is lower than the discharge rate under this scenario. Generally, for the RCP8.5 scenario, the changes in the signature indices in both high discharges and low discharges are significant.

Position uncertainties of AGATA pulse-shape analysis estimated via the bootstrapping method

The unprecedented capabilities of state-of-the-art segmented germanium-detector arrays, such as AGATA and GRETA, derive from the possibility of performing pulse-shape analysis. The comparison of the net- and transient-charge signals with databases via grid-search methods allows the identification of the $$\gamma $$ γ -ray interaction points within the segment volume. Their precise determination is crucial for the subsequent reconstruction of the $$\gamma $$ γ -ray paths within the array via tracking algorithms, and hence the performance of the spectrometer. In this paper the position uncertainty of the deduced interaction point is investigated using the bootstrapping technique applied to $$^{60}$$ 60 Co radioactive-source data. General features of the extracted position uncertainty are discussed as well as its dependence on various quantities, e.g. the deposited energy, the number of firing segments and the segment geometry.

Fluorescence visualization of the intersegmental plane by bronchoscopic instillation of indocyanine green into the targeted segmental bronchus: determination of the optimal settings

Objective To determine the appropriate amount of indocyanine green for bronchial insufflation. Methods We enrolled 20 consecutive patients scheduled for anatomical segmentectomy in the Kochi Medical School Hospital. After inducing general anesthesia, 6 to 60 mL of 200-fold-diluted indocyanine green (0.0125 mg/mL) was insufflated into the subsegmental bronchi in the targeted pulmonary segmental bronchus. The volume of the targeted pulmonary segments was calculated using preoperative computed tomography. Fluorescence spread in the segmental alveoli was visualized using a dedicated near-infrared thoracoscope. Results The targeted segment was uniformly visualized by indocyanine green fluorescence in 16/20 (80.0%) cases after insufflating indocyanine green. A receiver operating characteristic curve indicated that the area under the curve was 0.984; the optimal cut-off volume of diluted indocyanine green for insufflation was 8.91% of the calculated targeted pulmonary segment volume. Conclusions The setting for indocyanine green insufflation was optimized for near-infrared fluorescence image-guided anatomical segmentectomy. By injecting the correct amount of indocyanine green, fluorescence-guided anatomical segmentation may be performed more appropriately.

Ophtalmoplethysmography in ocular blood flow assessment

Introduction and purpose. Ocular blood flow (OBF) impairment is observed in more than 50 % of all ocular disorders. There is often an association with systemic hemodynamics. To evaluate ophthalmoplethysmographic parameters in normal subjects taking into account individual frequency-response OBF characteristics. Methods. 251 subjects without ophthalmic pathological findings (except incipient cataract in elderly) were examined using ophtalmoplethysmograph OP-A (SKTB Optimed, Moscow, Russia, calibrated by optimized method). Ocular biometry, intraocular pressure, blood pressure (BP), heart rate (HR) were also evaluated. Probands were divided into subgroups by gender and age. Results. The duration of the anacrotic part of the pulse curve ranged between 0.23±0.04 sec and 0.32±0.06 sec; the duration of the catacrotic part of the pulse curve was between 0.58±0.09 sec and 0.75±0.11 sec; the anacrotic/catacrotic ratio ranged between 0.34±0.07 and 0.55±0.1; the systolic increase of ocular anterior segment volume (SIOASV) ranged between 7.35±3.21 μl and 11.15±4.42 μl; SlOASV per minute was between 464.1±153.6 μl and 578.1±175.7 μl. Time characteristics of the plethysmographic curve highly correlate with HR. Conclusions. Ophtalmoplethysmography is a valuable tool for OBF evaluation. Normal OBF ophthalmoplethysmographic parameters vary significantly (ranging between 165.6 and 1388.4 μl/min). OBF evaluation should not be performed without systemic BP and HR examination.