MRI Surveillance of Plastic Material Surgical Meshes: Experimental Model - Interim Results

The number of surgical procedures for abdominal wall defects is increasing, often requiring the insertion of plastic material meshes. Surveillance of patients with inserted plastic meshes requires an accurate determination of the position of the mesh. However, this is a difficult task, depending on the kind of mesh, magnetic resonance imaging (MRI) protocol or consistence of the surrounding tissue (fat, muscle, aponeurosis). The aim of our research was to develop an experimental model to test the ability of MRI to identify the exact position of surgical plastic meshes: polypropylene or polyester. To simulate the placement of a mesh in human body we developed a model built up from two pieces of tissue with dimensions of 40 cm x 20 cm, harvested from a pig with a weight of 120 kg. The meshes were situated for MRI evaluation between the two pieces: abdominal pig muscle respectively suprajacent abdominal pig wall subcutaneous fat, approximately 2 cm high. Five surgical meshes were scanned through six MRI sequences, in view of establishing an optimal MRI scanning protocol and best visible meshes. The MRI scans were evaluated by 5 radiologists with different degrees of training. Our results showed that the experimental model developed by us can be successfully used to test the ability of MRI to visualize different kind of plastic meshes. Also, our experiment has revealed that T1fl2D sequence is the best in highlighting meshes from surrounding tissue, and the best visualized Mesh was number 4, made of polyester. In conclusion, based on our experimental model, we should select a plastic mesh or MRI protocol which will allow an optimal post implantation monitoring. Modern technology of material�s fabrication can help to better identify the mesh itself using MRI scanning.

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Extended perfusion protocol for MS lesion quantification

Open Medicine ◽

10.1515/med-2020-0100 ◽

2020 ◽

Vol 15 (1) ◽

pp. 520-530

Author(s):

Eleftherios Kontopodis ◽

Kostas Marias ◽

Georgios C. Manikis ◽

Katerina Nikiforaki ◽

Maria Venianaki ◽

...

Keyword(s):

Statistical Analysis ◽

Magnetic Resonance ◽

Goodness Of Fit ◽

Accurate Determination ◽

Acquisition Time ◽

Minimal Extension ◽

Dce Mri ◽

Contrast Enhanced ◽

Demyelinating Lesions ◽

Mri Protocol

AbstractThis study aims to examine a time-extended dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) protocol and report a comparative study with three different pharmacokinetic (PK) models, for accurate determination of subtle blood–brain barrier (BBB) disruption in patients with multiple sclerosis (MS). This time-extended DCE-MRI perfusion protocol, called Snaps, was applied on 24 active demyelinating lesions of 12 MS patients. Statistical analysis was performed for both protocols through three different PK models. The Snaps protocol achieved triple the window time of perfusion observation by extending the magnetic resonance acquisition time by less than 2 min on average for all patients. In addition, the statistical analysis in terms of adj-R2 goodness of fit demonstrated that the Snaps protocol outperformed the conventional DCE-MRI protocol by detecting 49% more pixels on average. The exclusive pixels identified from the Snaps protocol lie in the low ktrans range, potentially reflecting areas with subtle BBB disruption. Finally, the extended Tofts model was found to have the highest fitting accuracy for both analyzed protocols. The previously proposed time-extended DCE protocol, called Snaps, provides additional temporal perfusion information at the expense of a minimal extension of the conventional DCE acquisition time.

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Flow-metabolism uncoupling in patients with asymptomatic unilateral carotid artery stenosis assessed by multi-modal magnetic resonance imaging

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x18783369 ◽

2018 ◽

Vol 39 (11) ◽

pp. 2132-2143 ◽

Cited By ~ 4

Author(s):

Jens Göttler ◽

Stephan Kaczmarz ◽

Michael Kallmayer ◽

Isabel Wustrow ◽

Hans-Henning Eckstein ◽

...

Keyword(s):

Contralateral Side ◽

Blood Oxygenation ◽

Carotid Revascularization ◽

Asymptomatic Patients ◽

Metabolic States ◽

Oxygenation Level ◽

Mri Scans ◽

Mri Protocol ◽

Revascularization Therapy ◽

Continuous Arterial Spin Labeling

Oxygen extraction (OEF), oxidative metabolism (CMRO2), and blood flow (CBF) in the brain, as well as the coupling between CMRO2 and CBF due to cerebral autoregulation are fundamental to brain's health. We used a clinically feasible MRI protocol to assess impairments of these parameters in the perfusion territories of stenosed carotid arteries. Twenty-nine patients with unilateral high-grade carotid stenosis and thirty age-matched healthy controls underwent multi-modal MRI scans. Pseudo-continuous arterial spin labeling (pCASL) yielded absolute CBF, whereas multi-parametric quantitative blood oxygenation level dependent (mqBOLD) modeling allowed imaging of relative OEF and CMRO2. Both CBF and CMRO2 were significantly reduced in the stenosed territory compared to the contralateral side, while OEF was evenly distributed across both hemispheres similarly in patients and controls. The CMRO2-CBF coupling was significantly different between both hemispheres in patients, i.e. significant interhemispheric flow-metabolism uncoupling was observed in patients compared to controls. Given that CBF and CMRO2 are intimately linked to brain function in health and disease, the proposed easily applicable MRI protocol of pCASL and mqBOLD imaging might serve as a valuable tool for early diagnosis of potentially harmful cerebral hemodynamic and metabolic states with the final aim to select clinically asymptomatic patients who would benefit from carotid revascularization therapy.

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Analysis of Clinical Diagnostic Value of High Frequency Colour Doppler Ultrasound for Abdominal Wall Endometriosis

Journal of Medical Imaging and Health Informatics ◽

10.1166/jmihi.2021.3618 ◽

2021 ◽

Vol 11 (3) ◽

pp. 1004-1012

Author(s):

Xiuchun Zhang

Keyword(s):

Blood Flow ◽

Abdominal Wall ◽

Doppler Ultrasound ◽

High Frequency ◽

Subcutaneous Fat ◽

Diagnostic Methods ◽

Surrounding Tissue ◽

Colour Doppler ◽

Abdominal Wall Endometriosis ◽

Colour Doppler Ultrasound

Abdominal wall endometriosis is a common endometriosis, which is located outside the endometrium, such as the myometrium or subcutaneous fat layer of the abdominal wall, forming a mass, active and infiltrating into the surrounding tissue, accompanied by menstrual pain, and seriously affecting the quality of life of patients. With the increasing operation of caesarean section and other traumatic operations, the incidence rate of abdominal wall endometriosis is increasing. Because of the variety of clinical manifestations of abdominal wall endometriosis, there are many kinds of diagnostic methods. Choosing the appropriate diagnostic methods to confirm abdominal wall endometriosis has become the primary work of diagnosis and treatment of abdominal wall endometriosis. This paper discusses the clinical value of high frequency colour doppler ultrasound in the diagnosis of abdominal wall endometriosis. Compared with the diagnosis of ordinary ultrasound and high frequency colour doppler ultrasound, the location, shape, size, boundary, internal echo, blood flow velocity, blood flow resistance and other parameters of the mass in the focus were observed. It is proved that the application of high-frequency colour doppler ultrasound can greatly improve the ultrasonic diagnosis rate of abdominal wall endometriosis, and it is non-invasive, radiation-free, low price, easy for patients to accept. It provides a high value clinical diagnosis basis for the early detection and treatment of abdominal wall endometriosis.

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CRITICAL ANALYSIS OF EXPERIMENTAL MODEL FOR STUDY OF ADHESIONS AFTER INCISIONAL HERNIAS INDUCED IN RATS’ AND REPAIR OF ABDOMINAL WALL WITH DIFFERENT BIOMATERIALS

ABCD Arquivos Brasileiros de Cirurgia Digestiva (São Paulo) ◽

10.1590/s0102-67202015000300008 ◽

2015 ◽

Vol 28 (3) ◽

pp. 178-182 ◽

Cited By ~ 5

Author(s):

Leonardo Carvalho SERIGIOLLE ◽

Renato Lamounier BARBIERI ◽

Helbert Minuncio Pereira GOMES ◽

Daren Athiê Boy RODRIGUES ◽

Sarah do Valle STUDART ◽

...

Keyword(s):

Abdominal Wall ◽

Experimental Model ◽

Primary Repair ◽

Statistical Significance ◽

Abdominal Cavity ◽

Incisional Hernia Repair ◽

Greater Omentum ◽

Abdominal Wall Defects ◽

Hernia Sac ◽

Incisional Hernias

Background: Adhesions induced by biomaterials experimentally implanted in the abdominal cavity are basically studied by primary repair of different abdominal wall defects or by the correction of incisional hernias previously performed with no precise definition of the most appropriate model. Aim: To describe the adhesions which occur after the development of incisional hernias, before the prosthesis implantation, in an experimental model to study the changes induced by different meshes. Methods: Incisional hernias were performed in 10 rats with hernia orifices of standardized dimensions, obtained by the median incision of the abdominal wall and eversion of the defect edges. Ten days after the procedure adhesions of abdominal structures were found when hernias were repaired with different meshes. Results: The results showed hernia sac well defined in all rats ten days after the initial procedure. Adhesions of the greater omentum occurred in five animals of which two also showed adhesions of small bowel loops besides the omentum, and another two showed liver adhesions as well as the greater omentum, numbers with statistical significance by Student's t test (p<0.05). Conclusion: Although it reproduces the real clinical situation, the choice of experimental model of incisional hernia repair previously induced implies important adhesions, with possible repercussions in the evaluation of the second operation, when different implants of synthetic materials are used.

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A clinically relevant in vivo model for the assessment of scaffold efficacy in abdominal wall reconstruction

Journal of Tissue Engineering ◽

10.1177/2041731416686532 ◽

2016 ◽

Vol 8 ◽

pp. 204173141668653 ◽

Cited By ~ 6

Author(s):

Jeffrey CY Chan ◽

Krishna Burugapalli ◽

Yi-Shiang Huang ◽

John L Kelly ◽

Abhay Pandit

Keyword(s):

Abdominal Wall ◽

Abdominal Wall Reconstruction ◽

Rabbit Model ◽

In Vivo Model ◽

Abdominal Wall Defects ◽

Tissue Samples ◽

Collagen Formation ◽

Hernia Formation ◽

Surgical Meshes

An animal model that allows for assessment of the degree of stretching or contraction of the implant area and the in vivo degradation properties of biological meshes is required to evaluate their performance in vivo. Adult New Zealand rabbits underwent full thickness subtotal unilateral rectus abdominis muscle excision and were reconstructed with the non-biodegradable Peri-Guard®, Prolene® or biodegradable Surgisis® meshes. Following 8 weeks of recovery, the anterior abdominal wall tissue samples were collected for measurement of the implant dimensions. The Peri-Guard and Prolene meshes showed a slight and obvious shrinkage, respectively, whereas the Surgisis mesh showed stretching, resulting in hernia formation. Surgisis meshes showed in vivo biodegradation and increased collagen formation. This surgical rabbit model for abdominal wall defects is advantageous for evaluating the in vivo behaviour of surgical meshes. Implant area stretching and shrinkage were detected corresponding to mesh properties, and histological analysis and stereological methods supported these findings.

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An optimal segmentation method for processing medical image to detect the brain tumor

Communications in Physics ◽

10.15625/0868-3166/15938 ◽

2021 ◽

Vol 31 (4) ◽

Author(s):

Ho Thi Thao ◽

Viet Cuong Phan ◽

Tuan Anh Le ◽

Hong Ha Nguyen ◽

Quang Thanh Ha ◽

...

Keyword(s):

Brain Tumor ◽

Surgical Planning ◽

Medical Physics ◽

Region Growing ◽

Surrounding Tissue ◽

Planning Time ◽

Mri Scans ◽

Tumor Region ◽

Sobel Edge Detection ◽

The Brain

In the field of medical physics, detection of brain tumor from computed tomography (CT) or magnetic resonance (MRI) scans is a difficult task due to complexity of the brain hence it is one of the top priority goals of many recent researches. In this article, we describe a new method that combines four different steps including smoothing, Sobel edge detection, connected component, and finally region growing algorithms for locating and extracting the various lesions in the brain. The computational algorithm of the proposed method was implemented using Insight Toolkit (ITK). The analysis results indicate that the proposed method automatically and efficiently detected the tumor region from the CT or MRI image of the brain. It is very clear for physicians to separate the abnormal from the normal surrounding tissue to get a real identification of related areas; improving quality and accuracy of diagnosis, which would help to increase success possibility by early detection of tumor as well as reducing surgical planning time. This is an important step in correctly calculating the dose in radiation therapy later.

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Expanded polytetrafluoroethylene and polypropylene in the repairing of abdominal wall defects in Wistar rats: comparative study

Acta Cirurgica Brasileira ◽

10.1590/s0102-86502006000600010 ◽

2006 ◽

Vol 21 (6) ◽

pp. 409-415 ◽

Cited By ~ 6

Author(s):

Armando José d'Acampora ◽

Fabrícia Slomski Joli ◽

Ricardo Tramonte

Keyword(s):

Connective Tissue ◽

Abdominal Wall ◽

Polypropylene Mesh ◽

Wistar Rats ◽

Fibrous Tissue ◽

Microscopic Analysis ◽

Surrounding Tissue ◽

Control Group ◽

Abdominal Wall Defects ◽

Surgical Wound

PURPOSE: To compare the use of polypropylene and PTFE meshes in the treatment of incisional hernias made experimentally on Wistar rats. METHODS: The experiment used 24 Wistar rats divided into three cohorts: C-A (ressection of a segment of abdominal wall), E-A (ressection and placement of PTFEe mesh), E-B (resection and placement of polypropylene mesh). After 28 days, the mesh and the surrounding tissue were removed and submitted to macroscopic analysis (assessment of the abdominal wall for presence of abscess in the surgical wound and/or skin necrosis, and adhesions) as well as microscopic analysis (presence of fibrosis, necrosis and abscess, counting of macrophages, mononuclears and polymorphonuclears). RESULTS: Adhesions and abscesses in the surgical wound were observed more commonly associated to the group treated with PTFEe. The size of the fibrous tissue was greater in the group treated with polypropylene. Cohort E-A showed PTFEe mesh enveloped by organized fine connective tissue. No groups presented necrosis on the site of the insertion. The highest mononuclear inflammatory reaction occurred in association to PTFEe when compared to the control group, but the findings for the polypropylene mesh were also significant when compared to the control group. In the analysis of the results obtained for cohorts E-A and E-B, a minimal occurrence of polymorphonuclears was noticed in both groups, which indicates low tissue reactivity to both materials used in the present experiment. CONCLUSION: Even with epithelization and proliferation of connective tissue, anchorage between PTFEe and abdominal wall is insufficient, which can result in reherniations.

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Semi-automated medulloblastoma segmentation and influence of molecular subgroup on segmentation quality

Neuro-Oncology ◽

10.1093/neuonc/noz167.060 ◽

2019 ◽

Vol 21 (Supplement_4) ◽

pp. iv14-iv14

Author(s):

Richard Dury ◽

Rob Dineen ◽

Anbarasu Lourdusamy ◽

Richard Grundy

Keyword(s):

Surrounding Tissue ◽

Common Source ◽

Manual Segmentation ◽

Molecular Subgroup ◽

User Input ◽

Group 4 ◽

Tumour Margin ◽

Calculated Volume ◽

Mri Scans ◽

Tumour Location

Abstract Medulloblastoma is the most common malignant brain tumour in children. Segmenting the tumour itself from the surrounding tissue on MRI scans has shown to be useful for neuro-surgical planning, by allowing a better understanding of the tumour margin with 3D visualisation. However, manual segmentation of medulloblastoma is time consuming, prone to bias and inter-observer discrepancies. Here we propose a semi-automatic patient based segmentation pipeline with little sensitivity to tumour location and minimal user input. Using SPM12 “Segment” as a base, an additional tissue component describing the medulloblastoma is included in the algorithm. The user is required to define the centre of mass and a single surface point of the tumour, creating an approximate enclosing sphere. The calculated volume is confined to the cerebellum to minimise misclassification of other intracranial structures. This process typically takes 5 minutes from start to finish. This method was applied to 97 T2-weighted scans of paediatric medulloblastoma (7 WNT, 6 SHH, 17 Gr3, 26 Gr4, 41 unknown subtype); resulting segmented volumes were compared to manual segmentations. An average Dice coefficient of 0.85±0.07 was found, with the Group 4 subtype demonstrating a significantly higher similarity with manual segmentation than other subgroups (0.88±0.04). When visually assessing the 10 cases with the lowest Dice coefficients, it was found that the misclassification of oedema was the most common source of error. As this method is independent of image contrast, segmentation could be improved by applying it to images that are less sensitive to oedema, such as T1.

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MRI diagnosis of cortical dysplasia in the immature brain

Epilepsia and paroxyzmal conditions ◽

10.17749/2077-8333.2020.12.1.36-50 ◽

2020 ◽

Vol 12 (1) ◽

pp. 36-50

Author(s):

M. V. Polyanskaya ◽

A. A. Demushkina ◽

F. A. Kostylev ◽

F. A. Kurbanova ◽

I. G. Vasilyev ◽

...

Keyword(s):

Young Children ◽

Focal Epilepsy ◽

High Amplitude ◽

Immature Brain ◽

Diagnostic Significance ◽

Mri Scans ◽

Mri Protocol ◽

Cortical Dysplasias ◽

Mri Diagnosis ◽

T2 Weighted Images

Introduction. Cortical dysplasias (CDs) encompass a wide variety of disorders that in most cases lead to epilepsy, especially in infants and young children. MRI diagnosis of CDs is a major part of presurgical examination of pediatric patients with resistant focal epilepsy.Aim. To identify MR markers of CD in the immature brain and develop an MRI protocol for early diagnosis of CDs.Materials and methods. Children aged <2 y.o. (total 128) diagnosed with focal epilepsy were examined over 2017-2019. All MRI scans were performed using the GE 3 T system (General Electric, USA) in the standard MR sequences including T2WI FSE, T1 SE, FLAIR, DWI, SWAN, and FSPGR BRAVO supported with anesthesiological assistance. Аll patients were divided into 3 groups according to the degree of brain maturity; of those, 28 patients had MR signs of CD.Results. The rate of detection of small-size cortical malformations, such as nodular heterotopies or focal cortical dysplasias was significantly higher in groups of patients whose brains (according to MR images) were at the infantile or adult phases of myelination. In children with the isointensive phase myelination, only large cortical dysplasias could be identified. In the first phase, the focal malformations had low amplitude signals in T2-weighted images and high amplitude signals in T1, unlike those in adult patients. In the isointensive phase, the quality of visualization was significantly reduced and provided poor diagnostic information.Conclusion. The results confirm the diagnostic significance of early (before age of 5 months) MRI testing in cases with suspected CD-associated focal epilepsy. However, at the period between 5 and 12 months of age, MR imaging was ineffective for CD diagnosing. Later, in the period from 12 to 15 months, the MRI ability to identify the CDs gradually increased. We consider the standard T2 weighted images with high TR values, the most effective MR modality for diagnosing CDs in young children.

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A novel model for the investigation of orthotopically growing primary and secondary bone tumours using intravital microscopy

Laboratory Animals ◽

10.1258/002367705774286411 ◽

2005 ◽

Vol 39 (4) ◽

pp. 377-383 ◽

Cited By ~ 11

Author(s):

F M Klenke ◽

T Merkle ◽

J Fellenberg ◽

A Abdollahi ◽

P E Huber ◽

...

Keyword(s):

Experimental Model ◽

Intravital Microscopy ◽

Soft Tissues ◽

Surrounding Tissue ◽

Bone Tumours ◽

Immunodeficient Mice ◽

Cranial Window ◽

Malignant Bone Tumours ◽

Novel Model

Here is reported the development of an experimental model using intravital microscopy as a tool to orthotopically investigate malignant bone tumours. Although up to 85% of the most frequently occurring malignant solid tumours, such as lung and prostate carcinomas, metastasize into the bone, and despite the knowledge that a tumour's course may be altered by its surrounding tissue, there is no adequate experimental model available enabling the investigation of orthotopically grown bone tumours in vivo. Intravital microscopy is an internationally accepted experimental method, used in various acute and chronic animal models, that enables qualitative and quantitative analysis of the angiogenesis, microcirculation, growth behaviour, etc. of various benign and malignant tissues. Non-invasive investigations of up to several weeks are possible. Additionally, tissue samples can be taken after termination of the in vivo experiments for further ex vivo investigation (histology, immunohistochemistry, molecular biology, etc.), elucidating the mechanisms that underlie the in vivo observations. Severe combined immunodeficient mice were fitted with a cranial window preparation where the calvaria served as the site for orthotopic implantation of the solid human tumours Saos-2 osteosarcoma (primary) and A 549 lung carcinoma and PC-3 prostate carcinoma (secondary). In all preparations, the take rate was 100%. Histological assessment confirmed the data obtained in vivo, showing typical tumour growth with infiltration of the surrounding osseous and soft tissues. This novel model serves as a valuable tool in understanding the biology of primary and secondary bone tumours in physiological and pathophysiological situations, with implications for the most areas of tumour therapy such as chemotherapy, radiation and antiangiogenesis.

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