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Andrea Degiovanni
- 502306
- Phd: 40th cycle
- Department of Veterinary Sciences
- Matriculation number: 726238
Phd thesis
A NOVEL NONINVASIVE EVALUATION OF THE CANINE GASTROINTESTINAL TRACT: THE ROLE OF THE SHEAR WAVE ELASTOGRAPHY
● Scientific background/state of the art:
The term “multiparametric ultrasound” includes a range of non-invasive ultrasonographic techniques that complement bidimensional ultrasound (US) exam by providing additional diagnostic information. Elastography is among the most promising methods (1). This technique mimics manual palpation and measures tissue stiffness based on the evidence that parenchyma affected by different pathologies alters its elasticity (1). Two methods are available: Strain Elastography (SE) and Shear Wave Elastography (SWE). The former provides semi-quantitative results, while the latter, more recent, provides quantitative data( 2,3). In human medicine SWE is currently used for the liver, breast, prostate, thyroid, muscle and gastrointestinal (GI) tract evaluation (2,3,4). Several studies have successfully described its application in the diagnostic process of Crohn’s disease, the most common form of inflammatory boweldisease, to identify and differentiate inflammation from mural fibrosis (5,6). SWE is also used in the diagnosis of acute appendicitis (7), ulcerative colitis (8), chronic pancreatitis (9) and in the characterization of rectal lesions10. Recent studies have described the use of SWE in the evaluation of both healthy and diseased organs in dogs (11,12) and cats (12,13). The high prevalence and different etiology of GI diseases, whicho ften alter the GI wall architecture, combined with the ease of performing US examinations in dogs due to their thinner abdominal wall, which allows for better probe-organ contact and improved image quality, make the GI tract a suitable candidate for SWE assessment. Two publications involving dogs have analyzed the GI tract. Results are promising and highlight the feasibility of SWE to measure the jejunal mucosa stiffness in healthy dogs (14) and the use of SWE in the diagnostic process of granulomatous colitis (15).
● Aims:
Based on these premises, the general aim of the PhD project is to use SWE to measure the wall stiffness of specific GI segments, which are routinely identified and evaluated during US exam of the GI tract, both in healthy and diseased dogs. The segments targeted for SWE examination will include the gastric fundus, descending duodenum, terminal jejunum, terminal ileum and descending colon. The research project has two specific aims:
1) To measure the wall stiffness of the selected GI segments in a population of healthy dogs, thereby establishing normal reference intervals for the canine species.
2) To compare the wall stiffness of the same GI segments in a population of dogs with enteropathies, either inflammatory or neoplastic, with those of the control group.
Should a sufficiently large cohort of dogs affected by both inflammatory and neoplastic diseases be enrolled, an additional objective of the study will be to assess the diagnostic performance of SWE in differentiating between inflammatory and neoplastic conditions, a long-standing diagnostic challenge in the field of imaging.
● Materials and methods:
This multicenter observational prospective study involves two populations of dogs, healthy and diseased, selected among patients from the Veterinary Hospitals of the Department of Veterinary Science of Turin and Bologna. It is expected to enroll between 62-77 healthy and 35 diseased dogs [Sample size: significance level 0.05 (5%); statistical power 80% (β = 0.2); estimated medium effect size (Cohen’s d = 0.5)]. Inclusion criteria for healthy dogs include absence of GI symptoms for at least two months, and normal results from: clinical examination, complete blood count, serum biochemistry (ALPK, ALT, AST, ALB, TP, CREA, BUN, GLU), fecal analysis by fecal flotation and US exam. Diseased dogs are included based on clinical history, US exam and histological diagnosis of inflammatory or neoplastic GI disease. All dogs will undergo SWE, performed concurrently with US exam. Both examinations will be conducted using a Philips EPIQ Elite ultrasound system. SWE will be performed using dedicated software (Philips ElastoQ) and a linear probe (L5–18 MHz). GI wall stiffness will be expressed as elasticity (E) measured in kilopascals (kPa). In every dog three measurements will be taken by placing a sampling box on the anterior wall of each selected GI segment and the result will be expressed as the mean of the three measurements. To establish reference intervals for GI wall stiffness in healthy dogs, MedCalc software will be used. Parametric or non-parametric statistical tests will be performed to evaluate the differences between healthy and diseased dogs. Data collection will be carried out during the 1st and 2nd year. In 3rd year, data analysis and publication will be conducted, along with the development of additional related projects.
● Expected results:
The hypotheses related to the different developments of the PhD project are as follows:
1) Normal reference intervals for GI wall stiffness could be defined for each segment using SWE. Obtaining quantitative data and establishing normal reference intervals is essential for distinguishing between healthy and diseased organs.
2) Pathological GI segments may exhibit higher stiffness compared to the healthy ones. In humans it is well documented that, in the presence of inflammatory or neoplastic conditions, the physical characteristics of the GI wall change due to the development of fibrosis and cellular infiltration.
It’s also expected that neoplastic GI segments may demonstrate greater stiffness than inflammatory ones, as a result of neoangiogenesis, fibrosis and infiltration by neoplastic cells. This evidence could streamline the diagnostic workflow and reduce the patient's exposure to anesthetic risks, invasive procedures (cytology or biopsy) and contrast agents or ionizing radiation.
● Bibliography:
1) Paratore M, Garcovich M, Ainora ME et al.; The Role of Transabdominal Ultrasound Elastography in Gastrointestinal Non-Liver Diseases: Current Application and Future Prospectives;Diagnostics;13(13):2266. 2023.
2) Sigrist RMS, Liau J, Kaffas AE et al., Ultrasound Elastography: Review of Techniques and Clinical Applications; Theranostics;7(5):1303-1329. 2017.
3) Cosgrove D, Piscaglia F, Bamber J et al.; EFSUMB guidelines and recommendations on the clinical use of ultrasound elastography. Part 2: Clinical applications; Ultraschall Med.;34(3):238-53.2013.
4) Săftoiu A, Gilja OH, Sidhu PS et al.; The EFSUMB Guidelines and Recommendations for the Clinical Practice of Elastography in Non-Hepatic Applications: Update 2018; Ultraschall Med.;40(4):425-453. 2019.
5) Goertz RS, Lueke C, Widner D et al.; Acoustic radiation force impulse (ARFI) elastography of the bowel wall as a possible marker of inflammatory activity in patients with Crohn’s disease. Clinical Radiology; 73:678. e1-678.e5. 2018.
6) Dillman JR, Stidham RW, Higgins PD et al.; US elastography-derived shear wave velocity helps distinguish acutely inflamed from fibrotic bowel in a Crohn disease animal model; Radiology;267(3):757-766. 2013.
7) Cha SW, Kim IY, Kim YW; Quantitative measurement of elasticity of the appendix using shear wave elastography in patients with suspected acute appendicitis; Plos One;9(7):101292. 2014.
8) Goertz RS, Lueke C, Schellhaas B et al.; Acoustic radiation force impulse (ARFI) shear wave elastography of the bowel wall in healthy volunteers and ulcerative colitis; Acta Radiologica Open;8(4):1-7. 2019.
9) Kojima H, Sofuni A, Sugimoto K et al.; Efficacy of share wave elastography for the diagnosis of chronic pancreatitis; J Hepatobiliary Pancreat Sci.;30:351-359. 2023.
10) Li T, Lu M, Li Y et al.; Quantitative Elastography of Rectal Lesions: The Value of Shear Wave Elastography in Identifying Benign and Malignant Rectal Lesions; Ultrasound Med Biol.,45 (1): 85-92. 2019
11) Jung JW, Je H, Lee SK et al.; Two-Dimensional Shear Wave Elastography of Normal Soft Tissue Organs in Adult Beagle Dogs; Interobserver Agreement and Sources of Variability; Front Bioeng Biotechnol.;8:979. 2020.
12) Ercolin ACM, Uchôa AS, Aires LPN et al.; Use of New Ultrasonography Methods for Detecting Neoplasms in Dogs and Cats: A Review; Animals;14(2):312. 2024.
13) Kim K, Lee J, So J et al.; Feasibility and Reliability of Two-Dimensional Shear-Wave Elastography of the Liver of Clinically Healthy Cats; Front Vet Sci.;7:614750. 2020.
14) Spużak J, Kubiak K, Glińska-Suchocka K et al.; Accuracy of real-time shear wave elastography inthe assessment of normal small intestine mucosa in dogs; Pol J Vet Sci.;22(3):457-461. 2019.
15) Cordella A, Stock E, Van de Maele I et al.; Use of Contrast-Enhanced Ultrasonography and Shear-Wave Elastography in the Diagnosis of Granulomatous Colitis in a French Bulldog; Vet Sci.;8(7):133. 2021.
Training:
18th November 2017 Graduation at the Department of Veterinary Sciences (DSV), University of Turin (UniTo), Italy Graduation grade: 102/110 Title of Degree Thesis:” Arthrosynovitis due to Leishmania: clinical evaluation and therapeutic response"
November 2017 Obtaining the license to practice the veterinary profession and registration in the Professional Association of Veterinary Physicians of Turin
February 2023- November 2024 Second-Level University Master’s Degree in “Specialized Ultrasonology in Small Animal Veterinary Medicine,” Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell’Emilia (BO), Italy
1th November 2024- In progress PhD student- Doctoral school PhD in Veterinary Sciences for Animal Health and Food Safety. Department of Veterinary Sciences (DSV), University of Turin (UniTo), Italy