Site Of Leak Research Articles

The relationship between alcohol consumption and outcomes after gastrointestinal surgery: a systematic review and meta-analysis.

The study aimed to summarise the evidence of the association between preoperative alcohol consumption and postoperative complications in gastrointestinal surgeries. Comprehensive searches of MEDLINE, EMBASE, and Cochrane databases were undertaken to identify original studies investigating the association between preoperative alcohol consumption and postoperative complications occurring within 30days of surgery. The primary outcome was 30-day mortality risk and secondary outcomes included postoperative complications such as surgical site infections and risk of anastomotic leak. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using a random effects model. In total, 3601 reports were identified and reviewed for eligibility, then data was extracted from 26 studies that met inclusion criteria. 13 studies were included in the meta-analysis. The total number of patients in the meta-analysis was 686 181 including 20 163 with a high alcohol intake. Clearly defined high preoperative alcohol consumption was associated with an increased risk of postoperative complications including 30-day mortality (OR = 1.56; 95% CI: 1.07-2.28). The risk of anastomotic leak was significantly increased in those undergoing colorectal surgery with a high alcohol intake, OR 2.17 (95% CI: 1.74-2.72). An increase in risk was also found for surgical site infections in those undergoing gastrointestinal surgery with high alcohol intake. (OR = 1.32; 95% CI: 1.15-1.53). Preoperative alcohol consumption was associated with an increased risk of 30-day mortality, anastomotic leak and surgical site infections. Preoperative modulation of alcohol intake may influence post-operative complications after gastrointestinal surgery.

Identification of leakage sites in central serous chorioretinopathy using optical coherence tomography and the assessment of the characteristics of the biomarkers.

To identify optical coherence tomography (OCT)-based imaging biomarkers that can localize focal leakage points without fluorescein angiography in central serous chorioretinopathy (CSC). This retrospective case-control study analyzed 119 consecutive patients (123 eyes) with CSC between April 2018 and February 2024, comprising 66 eyes with focal-leakage type and 57 eyes with diffuse-leakage type. We assessed leakage sites using OCT, and the proportions of OCT findings were compared between focal- and diffuse-leakage types. Hyporeflective lucency signs were observed in 27 eyes (40.9%) with focal-type CSC, while no such signs were detected in diffuse-type CSC cases (0.0%; P < 0.001). In focal-type CSC, these signs were exclusively localized to leakage points, with no occurrence in other areas within serous retinal detachment. Microrip of retinal pigment epithelium and subretinal hyperreflective material were identified in 23 (34.8%) and 47 (71.2%) eyes with focal-type CSC, respectively, and also in eyes with diffuse-type CSC (5.3% and 19.3%, respectively; P < 0.001 for both comparisons). Only the hyporeflective lucency sign is present exclusively in focal leakage points of fluorescein angiography. Our findings suggested that the hyporeflective lucency sign may serve as a potential therapeutic target in CSC.

Lymphatic leaks – success of intranodal lymphangiogram first strategy

BackgroundLymphatic leaks are associated with significant mortality and morbidity. Intranodal lymphangiography (ILAG) involves the direct injection of ethiodised lipid into the hilum of lymph nodes. It is diagnostic procedure that can have therapeutic effects secondary to a local sclerosant effect. The aim of the study is to describe the technical and clinical success of ILAG and adjunctive lymphatic interventions performed as first line interventional techniques for lymphatic leaks refractory to conservative and medical management in a multicentre cohort of patients with symptomatic large volume lymphatic leaks.MethodsMulticentre retrospective study of all lymphatic interventions performed between 2017–2023 in patients with large volume lymphatic leaks (> 500 ml a day). Intranodal lymphangiography was performed initially with technical success defined as opacification of the lymphatics at the aortic bifurcation and demonstration of lymphatic leak on the index ILAG procedure or immediate post procedural CT was recorded. Lymphatic embolisation was performed with a combination of direct puncture or transvenous cannulation with glue and or coil embolisation of the thoracic duct or leak point and in cases with refractory leak. Clinical success was defined as reduction in drain output to less than 20 mL per 24 h, or no further insensible lymph leak. Time to clinical success after ILAG and adjunctive embolisation was recorded.ResultsILAG alone lead to clinical success in 14 of 32 (44%) patients after a median of 14 days. Subsequent embolisation was performed in 12 refractory cases; this was successful in 8 (67%) at median of 8 days. Overall clinical success of all lymphatic interventions was 69% (22 of 32 patients) at a median of 11 days (IQR 5–34). No statistically significant correlation between the site of leakage, aetiology or embolisation technique correlated with clinical success. Decision to proceed to repeat ILAG or an adjunct procedure was made on a clinical basis, following multidisciplinary discussion.ConclusionsILAG can be employed a first line interventional therapeutic technique to treat clinically significant lymphatic leaks that are refractory to conservative and medical management. Adjunctive procedures, including embolisation, can be considered as part of clinical decision making after a period of 1–2 weeks’ watchful waiting in continuingly refractory cases.

Efficacy of a shortened oral antibiotic bowel decontamination in minimally invasive surgery for diverticular disease

Introduction Infectious complications, such as anastomotic leakage (AL) and surgical site infections (SSI), remain a significant challenge in colorectal surgery. Consequently, there is growing interest in oral antibiotic bowel decontamination with non-absorbable antibiotics (selective digestive decontamination, or SDD), which can reduce perioperative complications while also minimizing antibiotic use. This study aimed to determine whether a three-day SDD regimen is as effective as a seven-day regimen in preventing postoperative complications in laparoscopic diverticular surgery. Methods A bicenter data analysis of prospectively and retrospectively collected patient data was performed. Three-day versus seven-day perioperative use of an SDD-based regimen (polymyxin B, gentamicin, vancomycin and amphotericin B) in patients undergoing minimally invasive surgery for diverticular disease was compared using non-inferiority analysis. Results A total of 469 patients were included in the analysis: 101 patients received a three-day perioperative SDD regimen, while 368 patients received a seven-day regimen. Due to use of routine clinical data, no control cohort available. The overall complication rate was 16.5% in both groups. AL and SSI occurred in 2.0% and 6.0% of the three-day group, and in 1.4% and 6.3% of the seven-day group, respectively, with no significant differences between the groups. However, for wound infections and overall infectious complications, the three-day regimen can be considered non-inferior to the seven-day regimen. Our data did not confirm the non-inferiority of the SDD3 regimen compared to the SDD7 regimen for AL. Discussion We report low rates of AL and other surgical and non-surgical complications in minimally invasive diverticular disease surgery. The low complication rates demonstrate non-inferiority regarding SSI. Our findings are consistent with recent evidence highlighting the positive impact of perioperative SDD treatment on SSI and infectious complications.

Postoperative CSF Rhinorrhoea.

Cerebrospinal fluid (CSF) rhinorrhoea is a well known complication following skull base surgery. Identifying the site of leak is the most important determinant for the appropriate approach in the further management of the case. Either transcranial or transnasal approaches may be used, alone or in combination, as deemed appropriate. The success of the repair depends on the site of the fistula, the timing of surgery, and patient factors. Discussion of two illustrative cases is presented here to describe the challenges faced by the neurosurgeon in the recognition and the immediate and definitive management of postoperative CSF rhinorrhoea and various strategies for a successful outcome in their repair.

Current status of postoperative morbidity following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal cancer with peritoneal metastasis: a prospective single-center observational study.

This study aimed to evaluate current morbidity rates following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with colorectal cancer and peritoneal metastasis. A total of 42 patients who underwent CRS and HIPEC for colorectal cancer with peritoneal metastasis at a single tertiary referral center between January 2022 and December 2022 were included. Perioperative outcomes and postoperative complications were prospectively assessed. The mean peritoneal cancer index (PCI) was 16.0. The distribution of PCI scores was as follows: <10, 33.3%; 10-19, 26.2%; and ≥ 20, 40.5%. Completeness of the cytoreduction (CCR) scores were as follows: 57.1% of patients achieved CCR-0, 16.7% achieved CCR-1, 7.1% achieved CCR-2, and 19.0% achieved CCR-3. The mean operation time was 9.1 hours, and the median hospital stay was 17.0 days. Postoperative complications occurred within 30 days in 47.6% of cases and between 30 and 60 days in 11.9% of cases. Reoperation within 30 days was required in 5 cases, and 1 patient died within 30 days. The most common complications were pleural effusion (5 patients), anastomosis site leakage (3 patients), and pneumonia (3 patients). Patients with higher PCI scores were more likely to experience complications (P = 0.038). Although CRS and HIPEC are still associated with high morbidity and mortality compared to other colorectal surgeries, outcomes have improved with increased experience. These results suggest that the procedure is becoming a more acceptable treatment option over time.

An Analytical Solution for the Steady Seepage of Localized Line Leakage in Tunnels

This paper proposes an analytical solution for the seepage field when a localized line leakage occurs in a tunnel by accurately considering the boundary conditions at the leakage site, which overcomes the problem of current methods, such as the equivalent method or methods improving on the existing analytical solution for fully drained tunnels, being unable to give an accurate analytical solution. First, the semi-infinite seepage region is converted into a rectangular seepage region using two conformal transformations. Subsequently, in order to accurately consider the boundary conditions at the leakage site, the rectangular seepage region with a discontinuous boundary is divided into three subregions with continuous boundaries, and the water head solution for each subregion is given by using the separated variable method. Finally, the principle of orthogonality of trigonometric functions is specially adopted to construct a non-homogeneous system of equations to solve the unknowns in the analytical solution, and through the inverse transformation of the conformal transformation, an analytical solution for the steady-state seepage field when localized line leakage occurs in a tunnel is obtained. The solution proposed is verified by its satisfactory agreement with the numerical simulation results and existing experimental results, and is much more accurate than the existing analytical solution. In addition, the proposed analytical solution is much less computationally demanding compared to numerical simulations. Finally, the capability of the proposed analytical solution is demonstrated by a parametric analysis of the tunnel burial depth, leakage location, and leakage width, and some meaningful conclusions are drawn.

Investigation of oil spills in pipelines under pressureless flow conditions

In order to assess the losses and environmental impact during oil pipeline operations due to oil spills, it is essential to determine the volume of spilled oil. Generally, the existing mathematical models for calculating the amount of hydrocarbons spilled in accidents are based on the hydraulics of monophasic flow of liquid and gas through openings and tubes. However, appropriate evaluation and calculation methods for multiphase flows are almost non-existent in the literature and regulatory documents. Therefore, the development and application of methods for accurately determining the volume of oil or gas released into the environment from pipelines under various conditions deserve special attention. Analysis shows that in the accident-prone section of pipelines, due to the loss of integrity, a ballast volume forms when the liquid is discharged from the pipeline into the environment. Typically, for assessing oil spills, two points – maximum and minimum – are marked in the profile at the damaged and perforated section. A graph reflecting the distribution of hydrostatic pressure is constructed in this area. It is mistakenly assumed that the pressure at the leak point (at the point with the minimum height) is maximal, using the formula patm+ρghP. However, in reality, atmospheric pressure occurs at the minimum point, which is at the leak site. This article investigates the assessment of pressureless oil spills in pipelines with varying terrain profiles and presents possible scenarios. It also demonstrates, based on the principle of flow continuity, that complete emptying of the pipeline due to accidental leaks is impossible. In the event of oil spills, the complete drainage of the pipeline in a gravity flow mode is only possible if there are perforations at all the extremal points of the pipeline profile.

Microglial activation without peripheral immune cell infiltration characterises mouse and human cerebral small vessel disease.

Cerebral small vessel diseases (SVDs) involve diverse pathologies of the brain's small blood vessels, leading to cognitive deficits. Cerebral magnetic resonance imaging (MRI) reveals white matter hyperintensities (WMHs), lacunes, microbleeds and enlarged perivascular spaces in SVD patients. Although correlations of MRI and histopathology help to understand the pathogenesis of SVD, they do not explain disease progression. Mouse models, both genetic and sporadic, are valuable for studying SVD, but their resemblance to clinical SVD is unclear. The study examined similarities and differences between mouse models of SVDs and human nonamyloid SVD specimens. We analysed four mouse models of SVD (hypertensive BPH mice, Col4a1 mutants, Notch3 mutants and Htra1-/- mice) at different stages for changes in myelin, blood-brain barrier (BBB) markers, immune cell populations and immune activation. The observations from mouse models were compared with human SVD specimens from different regions, including the periventricular, frontal, central and occipital white matter. Postmortem MRI followed by MBP immunostaining was used to identify white matter lesions (WMLs). Only Notch3 mutant and hypertensive BPH mice showed significant changes in myelin basic protein (MBP) immunostaining, correlating with MRI patterns. These changes were linked to altered microglial morphology and focal plasma protein staining around blood vessels, without peripheral immune cell infiltration. In human specimens, both normal-appearing white matter (NAWM) and WMLs lacked peripheral cell infiltration. However, WMLs displayed altered microglial morphology, reduced myelin staining and occasional fibrinogen staining around arterioles and venules. Our data show that Notch3 mutants and hypertensive BPH/2J mice recapitulate several features of human SVD, including microglial activation, focal sites of demyelination and perivascular plasma protein leakage without peripheral immune cell infiltration.

Improved object detection network for pipeline leakage localization in the pneumatic system based on thermal images

The infrared thermal imaging method can effectively identify and locate leakage sites using the temperature characteristics of pneumatic system leakage. However, it is limited by the tiny dimensions of the objects, color shifts of varying background temperatures, and indistinctness of feature details. To address these issues, we integrate Omni-Dimensional Dynamic Convolution (ODDC), Squeeze-and-Excitation (SE) attention module, and Normalized Gaussian Wasserstein Distance (NWD) with You Only Look Once (YOLO) into a framework, named ODSW-YOLO, for the precise localization of leakage. Specifically, ODDC is employed to adjust the kernel parameters for improving the accuracy of detecting small targets. To reduce the influence of varying background temperatures, SE attention is adopted to extract key features. NWD is used to enhance the feature details by checking the small feature changes within the detection window. Finally, extensive experiments show that ODSW-YOLO improves the detection accuracy from 0.677 to 0.755, which surpasses the baseline model (YOLOv5).

A clinical study on the therapeutic effects of 577 nm micropulse laser photocoagulation treatment in early-stage CSCR patients

PurposeTo research the therapeutic effects of 577 nm micropulse laser photocoagulation (MLP) treatment in early-stage central serous chorioretinopathy (CSCR) patients.MethodsTwenty-two CSCR patients with 24 CSCR eyes were examined prior to MLP treatment. The examinations included best-corrected visual acuity (BCVA), fluorescein fundus angiography (FFA), indocyanine green angiography (ICGA), optical coherence tomography (OCT), optical coherence tomography angiography (OCTA) and microperimetry. After MLP treatment, all the subjects were reviewed at 30 days. The BCVA, macular function on microperimetry, subretinal fluid (SRF) height of the macula on OCT, and choroid vascular density (VD) of the macular area on OCTA were compared before and after MLP treatment. The correlations between SRF height and visual function, choroid VD was analyzed separately.ResultsBCVA and macular function significantly increased and the SRF height of the macula significantly decreased after MLP treatment. BCVA and macular function were significantly negatively correlated with SRF height. The choroid VD was significantly increased after MLP treatment, and choroid VD in the leakage site part of the macula were significantly negatively correlated with the height of the SRF. A recurrent patient who received two MLP treatments also had a negative correlation between SRF and choroid VD during the course of disease.Conclusions577 nm MLP is safe and effective for early-stage CSCR patients, and treatment can restore macular structure and function. The increase in choroid VD of leakage site part after treatment is one of the key effects of MLP treatment for early-stage CSCR patients.

Analysis of risk factors for the failure of endoscopic endonasal skull base reconstruction

Objective: To analyze the influencing factors of skull base reconstruction failure after endoscopic endonasal skull base surgery (EESBS). Methods: A retrospective analysis was performed on 228 EESBS cases at the Affiliated Hospital of Qingdao University from 2018 to 2023. The clinical features associated with skull base reconstruction and postoperative cerebrospinal fluid leakage were collected and analyzed. Lasso regression was initially used for exploratory analysis, and risk factors for reconstruction failure were subsequently evaluated using multifactorial logistic regression. Results: A total of 157 cases of EESBS were included, with an overall reconstruction failure rate of 11.5% (18/157). No patients who underwent second-stage reconstruction with a tipped mucosal flap or multilayered free mucosal and fascial repair experienced further postoperative cerebrospinal fluid leakage. Variables identified through Lasso regression included history of surgery, history of radiotherapy, and site of leakage. Multifactorial logistic analysis showed that history of radiotherapy (OR=5.96,P=0.021) and site of leakage in the posterior skull base (OR=8.70,P=0.003) were significant risk factors for failure of skull base reconstruction. Conclusion: In cases with a history of radiotherapy and/or posterior skull base lesions in the operative area, reconstruction strategies should be strengthened to improve the success rate of one-stage repair, in particular, when intraoperative cerebrospinal fluid leakage occurs.

Study on the correlation between spontaneous cerebrospinal fluid rhinorrhea and increased intracranial pressure

Objective: To study the correlation between spontaneous cerebrospinal fluid rhinorrhea and increased intracranial pressure. Methods: Clinical data of patients with spontaneous cerebrospinal fluid rhinorrhea treated in the Department of Otorhinolaryngology of the Provincial Hospital of Shandong First Medical University from January 2019 to December 2023 and their epidemiology, clinical symptoms and signs, preoperative cerebrospinal fluid pressure, imaging data, leakage site, repair method and the presence or absebce of increased intracranial pressure were analysed. SPSS 23.0 software was used for statistical analysis. Results: Of the 57 patients with cerebrospinal fluid nasolacrimal leakage, 84.2%(48/57) were females and 15.8%(9/57) were males; 80.7%(46/57) were between 40 and 60 years old; and overweight and obese patients accounted for 75.4%(43/57). Of 57 patients, 35 patients received cranial MRI+magnetic resonance venography, and among them, 12(34.3%) patients were clinically with headache symptoms; the incidences of empty pterygoid and venous sinus stenosis were 40.0%(14/35) and 51.4%(18/35), respectively; and 33 patients underwent preoperative lumbar puncture examination, of whom 25(75.8%) patients had the increased cerebrospinal fluid pressure and 1 patient had idiopathic intracranial hypertension. All 57 patients underwent dural repair of the skull base, the postoperative follow-up period ranged from 3 to 60 months, and the success rate of surgery was 94.7%. The success rate was 100% in female patients and 33.3%(3/9) in male patients, including one with surgical failure receiving reoperation and two with postoperative recurrence in other areas of the skull base, with significant difference in the success rate of surgery between males and females (χ2=16.890, P<0.001). Conclusions: Most patients with spontaneous cerebrospinal fluid rhinorrhea have the increased cerebrospinal fluid pressures, but very few fulfil the diagnosis of idiopathic intracranial hypertension. The success rate of surgical repair alone is high, but some recurrences still exist, especially in male patients.

Transanal total mesorectal excision: Understanding indications, managing complications, and effective prevention methods

AbstractTransanal total mesorectal excision (TaTME) has emerged as a surgical method for treating rectal malignancies in the middle and lower third of the rectum over the past 15 years. This approach was adopted because of the challenges encountered in secure total mesorectal excision (TME). Patient selection criteria and the rationale for TaTME have evolved, leading to improved oncological outcomes and patient quality of life. The procedure includes inserting a unique platform through the anus, forming a purse‐string closure, and endoscopically sealing the lower rectum. The mesorectum is then removed laparoscopically following a ‘down‐to‐up’ approach, finalised with a transabdominal laparoscopic phase and anastomosis. Pelvic anatomy complexity poses challenges, including potential injuries to the urinary tract, surgical site leakage, sinus damage, sagittal vein harm, nerve injury, carbon dioxide embolism, bowel function disturbance, sphincter mechanism issues, and rectal abscess formation. Proficient anatomy knowledge, precise surgical techniques, and advanced technologies contribute to their prevention. In conclusion, TaTME offers a promising approach to rectal surgery with satisfactory oncological outcomes. However, vigilance is required to eliminate potential complications.

Fabrication of polyoxometalate dispersed cobalt oxide nanowires for electrochemically monitoring superoxide radicals from Hela cell mitochondria

An ultrasensitive electrochemical sensor is constructed by electrostatically adsorbing negatively charged hourglass-shape Cu-Polyoxometalate (POM) onto a positively charged CoO nanowires modified carbon cloth. The petaloid CoO nanowires have a large specific surface area that can well disperse open-structured Cu-POM to form Cu-POM@CoONWs@CC, which can maximumly expose catalytic active centers (Co2+ and Cu2+) and accelerate mass/charge transfer. In addition to the above advantages, the excellent electron exchange ability of Cu-POM and good conductivity of CoONWs@CC endow the sensor with good detection capability to H2O2 including a linear detection range of 0.05–1.4 μA μM−1, a low detection limit of 0.022 μM, high sensitivity of 110.48 μA μM−1, good selectivity and long-term stability. Due to the fast transformation of superoxide anion (O2∙‐) to H2O2, the sensor can indirectly monitor the electron leakage resulting in the formation of O2∙‐ via detecting H2O2. Afterwards, Hela cell mitochondria were extracted from the living cells that cultured with different mitochondrial inhibitors and the release of O2∙‐ from the corresponding mitochondrial complexes was monitored by the sensor. Through comparing the current signals, we determined that complex I is probably the main electron leakage site. This work could provide meaningful information for the diagnosis of certain oxidative stress diseases.

Application of ultrasound-guided intranodal lymphangiography in the diagnosis and treatment of chylous ascites after abdominal surgery.

Chylous leakage is a serious and challenging postoperative complication. The purpose of this study was to explore the application of ultrasound-guided intranodal lymphangiography in the diagnosis and treatment of chylous ascites following abdominal surgery. Ten patients with chylous ascites after abdominal surgery after ineffective conservative treatment such as low-fat diet, parenteral nutrition, and negative pressure drainage were included in this single-center retrospective study. Of these 10 patients, 9 developed chylous ascites after liver surgery, and 1 after a radical gastrectomy. Lymphangiography was successfully performed in all 10 patients. The average dosage of lipiodol used was 4.5 ml (range 3.5-7.0 ml). No procedure-related complications were observed after excluding unrelated factors. During lymphangiography, lipiodol leakage was directly observed in 3 cases, and in the other 5 cases, it was detected through abdominal computed tomography post-lymphangiography. Chylous ascites resolved solely through lymphangiography in 6 patients without requiring additional surgical intervention. Lymphangiography may help identify leakage sites in patients with chylous ascites unresponsive to conservative treatment and could potentially be effective in treating chylous ascites following abdominal surgery.

Influencing factors of bentonite for the directional electric repair of landfill HDPE membrane leakage in calcium ion solution

The timely repair of high-density polyethylene (HDPE) membrane leakage in landfills is an important means of environmental risk control, which is critical for preventing leachate from polluting groundwater and soil. Electric repair technology is expected to become a hot spot in the leakage repair of HDPE films, because it can solve the issues of complex operation, high costs, and security risks during the operation and closure of landfills. To explore the influence law of various technical factors on the electric repair process, we carried out single factor experiments on the main influencing factors such as the operation time, bentonite concentration and dispersant/bentonite dosage ratio, leakage size, and calcium concentration. We then explored the best technological conditions. The results showed that accumulation at the leakage site possessed a good repair effect with a permeability coefficient of 4.22 × 10−6 cm/s. Furthermore, we observed that the Zeta potential played an important role in the electric repair technology, where the higher the absolute value of the Zeta potential, the faster the electrophoretic migration rate of the bentonite particles, and the lower the permeability coefficient of accumulation. This study may serve as a theoretical basis and offer scientific guidance for the directional electric repair of HDPE membrane leakage during the operating period and after the closure of landfills.

Lymphoscintigraphy With SPECT-CT in Detecting the Site of Chyle Leak in Postoperative Patient.

Here is a case of chyle leak post McKeown esophagectomy. Lymphoscintigraphy with 99m Tc-filtered sulfur colloid revealed tracer accumulation along the thoracic duct and in the left hemithorax. Precise localization of leak was done by SPECT-CT imaging. This enabled timely surgical intervention and reduced further morbidity. This procedure is not only precise but also cost-effective as compared with the other available investigations.

Simulation of bench-scale CO2 injection using a coupled continuum-discrete approach

Unintended releases of CO2 from carbon capture and storage operations presents the risk of atmospheric emissions and groundwater or surface water quality impacts. Given the potential impacts, it is valuable to have tools capable of predicting groundwater concentrations and likely pathways of CO2 migration in the subsurface. Traditional multiphase flow models struggle to simulate the discontinuous flow expected at leakage sites. This work applied a coupled continuum-discrete model, ET-MIP, to simulate a bench-scale injection of CO2. Results demonstrate the capability of ET-MIP to accurately capture gas fingering behaviour, and the complexity of multicomponent mass transfer observed in the experiment. Simulations were computationally efficient, allowing for the use of multiple displacement pressure realizations. CO2 migration in the subsurface was shown to be sensitive to mass transfer, as i) increased groundwater velocity can dissolve leaked CO2 prior to reaching the surface and ii) background dissolved gases in the subsurface can impact the rate of upwards gas movement, gas distribution, and the composition and persistence of the gas phase. The sensitivity to mass transfer suggests it may be preferable to monitor for low-solubility gases in the source mixture rather than CO2. These findings are applicable to other gases in the subsurface, such as hydrogen or methane migrating from geoenergy wells.

Structured Approach for Imaging and Treatment of Spontaneous Intracranial Hypotension: a Case-Based Review

Spontaneous intracranial hypotension (SIH) is an increasingly diagnosed condition typically characterized by orthostatic headache and other symptoms caused by a decrease in cerebrospinal fluid (CSF) volume. The initial imaging work-up for patients with high pretest probability of SIH begins with a brain MRI and total spine MRI. At our institution, if MRI demonstrates a spinal longitudinal extradural collection, dynamic CT myelography is performed to localize the CSF leak. Most spinal longitudinal extradural collections are ventral; thus, dynamic CT myelography is most commonly performed with the patient in the prone position to elucidate the site of leak. If a lateral or dorsal extradural CSF collection is evident on MRI, lateral decubitus digital subtraction myelography or lateral decubitus CT myelography could be performed to identify less-common sites of leak. If the MRI does not demonstrate an extradural CSF collection, then the patient undergoes a conventional myelogram. If the site of leak is not identified, this would typically be followed by bilateral lateral decubitus digital subtraction myelography. Treatment options are determined on the basis of the ability to accurately locate the site and type of leak. This review presents several SIH cases to elucidate the imaging modalities for diagnosis, management algorithm, and therapeutic options.Learning Objectives: To understand the imaging findings, management algorithm, and treatment options for spontaneous intracranial hypotension.