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Fluids and Barriers of the CNS Nov 2022Today's availability of medical imaging and computational resources set the scene for high-fidelity computational modelling of brain biomechanics. The brain and its...
BACKGROUND
Today's availability of medical imaging and computational resources set the scene for high-fidelity computational modelling of brain biomechanics. The brain and its environment feature a dynamic and complex interplay between the tissue, blood, cerebrospinal fluid (CSF) and interstitial fluid (ISF). Here, we design a computational platform for modelling and simulation of intracranial dynamics, and assess the models' validity in terms of clinically relevant indicators of brain pulsatility. Focusing on the dynamic interaction between tissue motion and ISF/CSF flow, we treat the pulsatile cerebral blood flow as a prescribed input of the model.
METHODS
We develop finite element models of cardiac-induced fully coupled pulsatile CSF flow and tissue motion in the human brain environment. The three-dimensional model geometry is derived from magnetic resonance images (MRI) and features a high level of detail including the brain tissue, the ventricular system, and the cranial subarachnoid space (SAS). We model the brain parenchyma at the organ-scale as an elastic medium permeated by an extracellular fluid network and describe flow of CSF in the SAS and ventricles as viscous fluid movement. Representing vascular expansion during the cardiac cycle, a prescribed pulsatile net blood flow distributed over the brain parenchyma acts as the driver of motion. Additionally, we investigate the effect of model variations on a set of clinically relevant quantities of interest.
RESULTS
Our model predicts a complex interplay between the CSF-filled spaces and poroelastic parenchyma in terms of ICP, CSF flow, and parenchymal displacements. Variations in the ICP are dominated by their temporal amplitude, but with small spatial variations in both the CSF-filled spaces and the parenchyma. Induced by ICP differences, we find substantial ventricular and cranial-spinal CSF flow, some flow in the cranial SAS, and small pulsatile ISF velocities in the brain parenchyma. Moreover, the model predicts a funnel-shaped deformation of parenchymal tissue in dorsal direction at the beginning of the cardiac cycle.
CONCLUSIONS
Our model accurately depicts the complex interplay of ICP, CSF flow and brain tissue movement and is well-aligned with clinical observations. It offers a qualitative and quantitative platform for detailed investigation of coupled intracranial dynamics and interplay, both under physiological and pathophysiological conditions.
Topics: Humans; Cerebral Ventricles; Subarachnoid Space; Pulsatile Flow; Computer Simulation; Brain; Magnetic Resonance Imaging; Cerebrospinal Fluid
PubMed: 36320038
DOI: 10.1186/s12987-022-00376-2 -
Respirology Case Reports May 2024Solitary respiratory papilloma is a rare epithelial tumour that can be categorized into multiple subtypes. The glandular type (Glandular papilloma, GP) is the rarest....
Solitary respiratory papilloma is a rare epithelial tumour that can be categorized into multiple subtypes. The glandular type (Glandular papilloma, GP) is the rarest. Most GP occurs in the proximal airways and is only rarely found in the lung parenchyma. In this article, we reported a case of GP in lung parenchyma.
PubMed: 38779541
DOI: 10.1002/rcr2.1389 -
Journal of Healthcare Engineering 2021Segmentation of pulmonary vessels in CT/CTA images can help physicians better determine the patient's condition and treatment. However, due to the complexity of CT...
Segmentation of pulmonary vessels in CT/CTA images can help physicians better determine the patient's condition and treatment. However, due to the complexity of CT images, existing methods have limitations in the segmentation of pulmonary vessels. In this paper, a method based on the separation of pulmonary vessels in CT/CTA images is investigated. The method is divided into two steps: in the first step, the lung parenchyma is extracted using the Unet++ algorithm, which can effectively reduce the oversegmentation rate; in the second step, the pulmonary vessels in the lung parenchyma are extracted using nnUnet. According to the obtained lung parenchyma segmentation results, the "AND" operation is performed on the original image and the lung parenchyma segmentation results, and only the blood vessels within the lung parenchyma are segmented, which reduces the interference of external tissues and improves the segmentation accuracy. The experimental data source used CT/CTA images acquired from the partner hospital. After the experiments were performed on a total of 67 sets of images, the accuracy of CT and CTA images reached 85.1% and 87.7%, respectively. The comparison of whether to segment the lung parenchyma and with other conventional methods was also performed, and the experimental results showed that the algorithm in this paper has high accuracy.
Topics: Algorithms; Humans; Lung; Thorax; Tomography, X-Ray Computed
PubMed: 34777735
DOI: 10.1155/2021/5763177 -
Medicina (Kaunas, Lithuania) Oct 2022Liver resection for malignant tumors should respect oncological margins while ensuring safety and improving the quality of life, therefore tumor staging, underlying... (Review)
Review
Liver resection for malignant tumors should respect oncological margins while ensuring safety and improving the quality of life, therefore tumor staging, underlying liver disease and performance status should all be attentively assessed in the decision process. The concept of parenchyma-sparing liver surgery is nowadays used as an alternative to major hepatectomies to address deeply located lesions with intricate topography by means of complex multiplanar parenchyma-sparing liver resections, preferably under the guidance of intraoperative ultrasound. Regenerative liver surgery evolved as a liver growth induction method to increase resectability by stimulating the hypertrophy of the parenchyma intended to remain after resection (referred to as future liver remnant), achievable by portal vein embolization and liver venous deprivation as interventional approaches, and portal vein ligation and associating liver partition and portal vein ligation for staged hepatectomy as surgical techniques. Interestingly, although both strategies have the same conceptual origin, they eventually became caught in the never-ending parenchyma-sparing liver surgery vs. regenerative liver surgery debate. However, these strategies are both valid and must both be mastered and used to increase resectability. In our opinion, we consider parenchyma-sparing liver surgery along with techniques of complex liver resection and intraoperative ultrasound guidance the preferred strategy to treat liver tumors. In addition, liver volume-manipulating regenerative surgery should be employed when resectability needs to be extended beyond the possibilities of parenchyma-sparing liver surgery.
Topics: Humans; Hepatectomy; Quality of Life; Liver Regeneration; Liver; Portal Vein; Treatment Outcome
PubMed: 36295582
DOI: 10.3390/medicina58101422 -
Frontiers in Medicine 2023Patients with impaired kidney function are at elevated risk for nephrotoxicity and hematotoxicity from peptide receptor radionuclide therapy (PPRT) for advanced...
OBJECTIVE
Patients with impaired kidney function are at elevated risk for nephrotoxicity and hematotoxicity from peptide receptor radionuclide therapy (PPRT) for advanced neuroendocrine tumors. Somatostatin receptor (SSR)-PET/CT imaging is the method of choice to identify sufficient SSR expression as a prerequisite for PRRT. Therefore, our study aimed to explore whether split renal function could be evaluated using imaging data from routine SSR-PET/CT prior to PRRT.
METHODS
In total, 25 consecutive patients who underwent SSR-PET/CT (Siemens Biograph mCT) before PRRT between June 2019 and December 2020 were enrolled in this retrospective study. PET acquisition in the caudocranial direction started at 20 ± 0.5 min after an i.v. injection of 173 ± 20 MBq [Ga]Ga-ha DOTATATE, and the kidneys were scanned at 32 ± 0.5 min p.i. The renal parenchyma was segmented semi-automatically using an SUV-based isocontour (SUV between 5 and 15). Multiple parameters including SUVmean of renal parenchyma and blood pool, as well as parenchyma volume, were extracted, and accumulation index (: renal parenchyma volume/SUVmean) and total kidney accumulation (: SUVmean x renal parenchyma volume) were calculated. All data were correlated with the reference standard tubular extraction rate (TER-MAG) from [Tc]Tc-MAG3 scintigraphy and glomerular filtration rate (GFR).
RESULTS
SUVmean of the parenchymal tracer retention showed a negative correlation with TER (: -0.519, < 0.001) and GFR (: -0.555, < 0.001) at 32 min p.i. The herein-introduced ACI revealed a significant correlation ( < 0.05) with the total tubular function (: 0.482), glomerular renal function (: 0.461), split renal function (: 0.916), and absolute single-sided renal function (: 0.549). The mean difference between the split renal function determined by renal scintigraphy and ACI was 1.8 ± 4.2 % points.
CONCLUSION
This pilot study indicates that static [Ga]Ga-ha DOTATATE PET-scans at 32 min p.i. may be used to estimate both split renal function and absolute renal function using the herein proposed "Accumulation Index" (ACI).
PubMed: 37448797
DOI: 10.3389/fmed.2023.1169451 -
World Journal of Surgical Oncology Mar 2023To evaluate perioperative safety and outcome of parenchyma-preserving pancreatectomy and risk factors of metastasis and recurrence for patients with solid...
BACKGROUND/OBJECTIVES
To evaluate perioperative safety and outcome of parenchyma-preserving pancreatectomy and risk factors of metastasis and recurrence for patients with solid pseudopapillary neoplasm (SPN).
METHODS
Demographic data, operative and pathological parameter, follow-up data of patients with SPN undergoing their first operation were collected in our single center from May 2016 to October 2021 and compared between regular pancreatectomy group and parenchyma-preserving surgery group. Risk factors for metastasis and recurrence were investigated.
RESULTS
A total of 194 patients were included, 154 of whom were female and the average age of all patients was 33 years old. Most patients were asymptomatic, with the most common complaint being abdominal pain or discomfort. Of them, 62 patients underwent parenchyma-preserving pancreatectomy including middle segment pancreatectomy and enucleation, and 132 patients underwent regular pancreatectomy including pancreaticoduodenectomy, distal pancreatectomy and total pancreatectomy. Patients in the parenchyma-preserving surgery group had a shorter duration of operation, less intraoperative bleeding, and decreased risk of combined organ removal and blood transfusion, with no statistical significance yet. The two groups exhibited a similar incidence of postoperative complications including grade B and C pancreatic fistula, delayed gastric emptying, postoperative pancreatic hemorrhage, and other complications, as well as radiological intervention, relaparotomy and the length of postoperative hospital stay. There were no perioperative deaths. All the patients, except 18 of those who discontinued follow-up, were alive with a median follow-up time of 31 months. Three patients in the regular pancreatectomy group were observed to have liver metastasis, and no metastasis was observed in the parenchyma-preserving surgery group. Significant risk factors for tumor metastasis and recurrence were tumor size, angioinvasion, and nerve infiltration.
CONCLUSIONS
Parenchyma-preserving surgery did not significantly increase the frequency of perioperative complications or recurrence and might be preferable if comprehensive conditions allow.
Topics: Humans; Female; Adult; Male; Pancreatic Neoplasms; Prognosis; Pancreatectomy; Pancreaticoduodenectomy; Postoperative Hemorrhage; Retrospective Studies; Pancreas; Treatment Outcome
PubMed: 37004027
DOI: 10.1186/s12957-023-03003-y -
Seminars in Cancer Biology Feb 2020The macro-metastasis/organ parenchyma interface (MMPI) was previously considered an inert anatomical border which sharply separates the affected organ parenchyma from... (Review)
Review
The macro-metastasis/organ parenchyma interface (MMPI) was previously considered an inert anatomical border which sharply separates the affected organ parenchyma from the macro-metastatic tissue. Recently, infiltrative growth of macro-metastases from various primary tumors was described in the brain, liver and lung, with significant impact on survival. Strikingly, the MMPI patterns differed between entities, so that at least nine different patterns were described. The MMPI patterns could be further classified into three major groups: displacing, epithelial and diffuse infiltrating. Additionally, macro-metastases are a source of further tumor cell dissemination in the affected organ; and these intra-organ metastatic dissemination tracks starting from the MMPI also vary depending on the anatomical structures of the colonized organ and influence disease outcome. In spite of their relevance, MMPIs and organ-specific dissemination tracks are still largely overlooked by many clinicians, pathologists and/or researchers. In this review, we aim to address this important issue and enhance our current understanding of the different MMPI patterns and dissemination tracks in the brain, liver and lung.
Topics: Humans; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Staging; Neoplasms; Organ Specificity
PubMed: 31647982
DOI: 10.1016/j.semcancer.2019.10.012 -
Current Oncology (Toronto, Ont.) Sep 2022Resection of lung metastases with curative intention in selected patients is associated with prolonged survival. Laser-assisted resection of lung metastases results in... (Review)
Review
BACKGROUND
Resection of lung metastases with curative intention in selected patients is associated with prolonged survival. Laser-assisted resection of lung metastases results in complete resection of a high number of lung metastases, while preserving lung parenchyma. However, data concerning laser lung resections are scarce and contradictory. The aim of this study was to conduct a systematic review to evaluate the utility of laser-assisted pulmonary metastasectomy.
METHODS
An electronic search in MEDLINE (via PubMed), complemented by manual searches in article references, was conducted to identify eligible studies.
RESULTS
Fourteen studies with a total of 1196 patients were included in this metanalysis. Laser-assisted surgery (LAS) for lung metastases is a safe procedure with a postoperative morbidity up to 24.2% and almost zero mortality. LAS resulted in the resection of a high number of lung metastases with reduction of the lung parenchyma loss in comparison with conventional resection methods. Survival was similar between LAS and conventional resections.
CONCLUSION
LAS allows radical lung-parenchyma saving resection of a high number of lung metastases with similar survival to conventional methods.
Topics: Humans; Retrospective Studies; Metastasectomy; Laser Therapy; Lung; Lung Neoplasms
PubMed: 36290825
DOI: 10.3390/curroncol29100548 -
CEN Case Reports Feb 2023Pathologic evaluation of the non-neoplastic renal parenchyma in tumor nephrectomy specimens is critical and can detect both renal-limited and systemic pathologies. We...
Pathologic evaluation of the non-neoplastic renal parenchyma in tumor nephrectomy specimens is critical and can detect both renal-limited and systemic pathologies. We report the case of a 69-year-old Punjabi male who underwent cytoreductive nephrectomy for advanced renal cell carcinoma after immunotherapy. We detected clinically unexpected leukocyte chemotactic factor 2 (LECT2) amyloidosis during pathologic analysis of the surrounding non-neoplastic renal parenchyma, which was confirmed by mass spectrometry. LECT2 amyloidosis occurs predominantly in Hispanic patients and has only rarely been described in Punjabi patients. This case highlights the importance of careful pathologic evaluation of the non-neoplastic renal parenchyma of nephrectomy specimens and raises awareness that LECT2 amyloidosis can occur outside of the typical demographic of Hispanic patients.
Topics: Humans; Male; Aged; Kidney; Nephrectomy; Amyloidosis; Carcinoma, Renal Cell; Kidney Neoplasms; Intercellular Signaling Peptides and Proteins
PubMed: 35986199
DOI: 10.1007/s13730-022-00728-9 -
Frontiers in Plant Science 2016This review examines the roles that ray and axial parenchyma (RAP) plays against fungal pathogens in the secondary xylem of wood within the context of the CODIT model... (Review)
Review
This review examines the roles that ray and axial parenchyma (RAP) plays against fungal pathogens in the secondary xylem of wood within the context of the CODIT model (Compartmentalization of Decay in Trees), a defense concept first conceived in the early 1970s by Alex Shigo. This model, simplistic in its design, shows how a large woody perennial is highly compartmented. Anatomical divisions in place at the time of infection or damage, (physical defense) alongside the 'active' response by the RAP during and after wounding work together in forming boundaries that function to restrict air or decay spread. The living parenchyma cells play a critical role in all of the four walls (differing anatomical constructs) that the model comprises. To understand how living cells in each of the walls of CODIT cooperate, we must have a clear vision of their complex interconnectivity from a three-dimensional perspective, along with knowledge of the huge variation in ray parenchyma (RP) and axial parenchyma (AP) abundance and patterns. Crucial patterns for defense encompass the symplastic continuum between both RP and AP and the dead tissues, with the latter including the vessel elements, libriform fibers, and imperforate tracheary elements (i.e., vasicentric and vascular tracheids). Also, the heartwood, a chemically altered antimicrobial non-living substance that forms the core of many trees, provides an integral part of the defense system. In the heartwood, dead RAP can play an important role in defense, depending on the genetic constitution of the species. Considering the array of functions that RAP are associated with, from capacitance, through to storage, and long-distance water transport, deciding how their role in defense fits into this suite of functions is a challenge for plant scientists, and likely depends on a range of factors. Here, we explore the important role of RAP in defense against fungal pathogens and the trade-offs involved from a viewpoint for structure-function relations, while also examining how fungi can breach the defense system using an array of enzymes in conjunction with the physically intrusive hyphae.
PubMed: 27881986
DOI: 10.3389/fpls.2016.01665