Littérature scientifique sur le sujet « Diagnostic imaging »

[Truncated abstract] Hypothesis: There is deficiency in the evidence base and scientific underpinning of existing diagnostic imaging pathways (DIP) for diagnostic endpoints. Objective: a) To carry out systematic review of literature in relation to use of diagnostic imaging tests for diagnosis and investigation of 78 common clinical problems, b) To identify deficiencies and controversies in existing diagnostic imaging pathways, and to develop a new set of consensus based pathways for diagnostic imaging (DIP) supported by evidence as an education and decision support tool for hospital based doctors and general practitioners, c) To carry out a trial dissemination, implementation and evaluation of DIP. Methods: 78 common clinical presentations were chosen for development of DIP. For general practitioners, clinical topics were selected based on the following criteria: common clinical problem, complex in regards to options available for imaging, subject to inappropriate imaging resulting in unnecessary expenditure and /or radiation exposure, and new options for imaging of which general practitioners may not be aware. For hospital based junior doctors and medical students, additional criteria included: acute presentation when immediate access to expert radiological opinion may be lacking and clinical problem for which there is a need for education. Systematic review of the literature in relation to each of the 78 topics was carried out using Ovid, Pubmed and Cochrane Database of Systematic Reviews. ... The electronic environment and the method of delivery provided a satisfactory medium for dissemination. Getting DIP implemented required vigorous effort. Knowledge of diagnostic imaging and requesting behaviour tended to become more aligned with DIP following a period of intensive marketing. Conclusions: Systematic review of literature and input and feedback from various clinicians and radiologists led to the development of 78 consensus based Diagnostic Imaging Pathways supported by evidence. These pathways are a valuable decision support tool and are a definite step towards incorporating evidence based medicine in patient management. The clinical and academic content of DIP is of practical use to a wide range of clinicians in hospital and general practice settings. It is source of high level knowledge; a reference tool for the latest available and most effective imaging test for a particular clinical problem. In addition, it is an educational tool for medical students, junior doctors, medical imaging technologists, and allied health care personnel.

The focus of the project has two aspects associated with tumour imaging. The primary and major focus of my thesis was to assess the potential of a radiolabelled agent, 99mTc-Hynic-Annexin V, for the in vivo imaging of apoptosis after chemotherapy and radiotherapy in nude mice bearing thymoma tumours. The second aspect of the thesis examines the potential of a glucose analog, 99mTclabelled 2-deoxyglucosamine (99mTc—ECDG), to detect tumours based on the increased glucose metabolism of tumours in an attempt to evaluate if it can substitute the PET agent, 18F— labelled fluorodeoxyglucose (lgF-FDG) for tumour detection. Apoptosis is a process whereby damaged cells undergo programmed cell death during which phosphatidylserine (PS) becomes extemalised. Annexin V is shown to have a high affinity for PS and has been demonstrated to bind in apoptotic cells. When radiolabelled, Annexin V acts as an imaging probe to detect apoptosis. Available literature revealed many modalities available for apoptosis detection but most are associated with many pitfalls. However, only nuclear medicine imaging is able to provide a non-invasive tool for the early assessment of apoptosis. Furthermore, 99mTc-Hynic-Annexin V has been the best characterised probe for detecting apoptosis to date. Several studies have reported good correlation of this agent with therapy-induced apoptosis. However none have reported on the comparisons of two modes of cancer treatment (chemotherapy and radiotherapy) in a thymoma mouse model.

There are two Gadolinium-based liver-specific contrast media for Magnetic Resonance Imaging on the market, Gd-BOPTA (MultiHance®, Bracco Imaging, Milan, Italy) and Gd-EOB-DTPA (Primovist®, Bayer Schering Pharma, Berlin, Germany). The aim of this study in two parts was to evaluate the dynamics of biliary, parenchymal and vascular enhancement using these contrast media in healthy subjects. Ten healthy volunteers were examined in a 1.5 T magnetic resonance system using three-dimensional Volumetric Interpolated Breath-Hold (VIBE) sequences for dynamic imaging with both contrast media – at two different occasions – until five hours after injection. The doses given were 0.025 mmol/kg for Gd-EOB-DTPA and 0.1 mmol/kg for Gd-BOPTA. The enhancement over time of the common biliary duct in contrast to the liver parenchyma was analyzed in the first study. This was followed by a study of the image contrasts of the hepatic artery, portal vein and middle hepatic vein versus the liver parenchyma.While Gd-EOB-DTPA gave an earlier and more prolonged enhancement of the biliary duct, Gd-BOPTA achieved higher image contrast for all vessels studied, during the arterial and portal venous phases. There was no significant difference in the maximal enhancement obtained in the liver parenchyma.At the obtained time-points and at the dosage used, the high contrast between the common biliary duct and liver parenchyma had an earlier onset and longer duration for Gd-EOB-DTPA, while Gd-BOPTA achieved higher maximal enhancement of the hepatic artery, portal vein and middle hepatic vein than Gd-EOB-DTPA. Diseases of the liver and biliary system may affect the vasculature, parenchyma, biliary excretion or a combination of these. The clinical context regarding the relative importance of vascular, hepatic parenchymal and biliary processes should determine the choice of contrast media for each patient and examination.

 

The increasing popularity of snakes and lizards as pets has led to an increasing demand of specialised veterinary duties in these animals. Diagnostic imaging is often a fundamental step of the clinical investigation. The interpretation of diagnostic images is complex and requires a broad knowledge of anatomy, physiology and pathology of the species object of the clinical investigation. Moreover, in order to achieve a correct diagnosis, the comparison between normal and abnormal diagnostic images, for all the diagnostic imaging modalities, is mandatory. In this PhD thesis the diagnostic imaging features of some snake and lizard species are described. The aim of all the works presented is to provide some normal atlases matching the normal gross and cross-sectional anatomy with the normal radiographic, ultrasonographic, CT features of some of the most popular pet lizard and snake specie. In Chapter I a review of literature regarding snakes and lizards is presented. The aim of this chapter is to review the most commonly used diagnostic imaging modalities as well as to make an updated collection of the available international references describing the normal and pathological imaging features in snakes and lizards. Most of papers describing radiography, ultrasonography, computed tomography, magnetic resonance imaging and other imaging modalities have been collected in order to overcome the lack of a unique reference regarding diagnostic imaging in snakes and lizards. The scientific aims and the outline of this thesis are presented in Chapter II. The general aim of this PhD thesis is to provide some useful anatomical and diagnostic imaging references in snakes and lizards. The first part of this work (Chapters III and IV) is focused on the description of the normal radiographic and computed tomographic features of the head of some snakes and lizards species. The second part (Chapters V to VII) is focused on the diagnostic imaging of the coelomic cavity; the description of the normal contrast enhanced computed tomographic features of the coelomic cavity of some lizards, the normal ultrasonographic features of the coelomic cavity of some snake species and the normal upper gastro-intestinal examination in the ball python are presented. In Chapter III the normal stratigraphic and cross sectional anatomy is matched with the normal radiographic and computed tomographic features of the head of the Boa constrictor. 4 boa constrictor’s cadavers head where used in this study. Radiographs of the head were taken in LL and DV projections using a high detail screen-film combination. CT scans scans of the head where performed in a CC and a LL direction with a slice thickness of 1,5mm and displayed in a bone window. 2 heads where dissected following a stratigraphic approach and 2 heads frozen for 24h (-20°C) and then sectioned into 3mm slices respecting the imaging protocol. All anatomical structures have been identified and labelled with the aid of available literature in the anatomical images and then matched on the corresponding radiographic and computed tomographic images. Radiographic and CT images provided a high detail for the visualisation of bony structures; soft tissues were not easily identified on radiographic and CT images. In Chapter IV the normal radiographic and contrast enhanced computed tomographic features of the head of the green iguana, common tegu and bearded dragon are described. The study included 4 cadavers for each considered species and 6 adult green iguanas, 4 tegus, 3 bearded dragons. Prior to the beginning of the radiographic and computed tomographic studies 2 cadavers were dissected following a stratigraphic approach and 2 cadavers were cross-sectioned for each species. Anatomical studies were performed following the same approach described in Chapter III. Both the radiographic and the computed tomographic studies were performed only in live animals. Radiographic studies included a LL and a DV projection. Pre- and post- contrast computed tomographic studies of the head were performed in a CC direction. CT images were displayed in both bone and soft tissue windows. Individual anatomical structures were first recognised and labelled on the anatomic images and then matched on radiographs and CT images. Radiographic studies provided a good detail both of the soft tissues (especially in the green iguana) and of the bony structures. CT images provided an excellent detail of the bony structures in all the considered species. The soft tissues were clearly outlined only in the green iguana. In the common tegu and the bearded dragon only the eyes were clearly outlined from the remaining soft tissues. In Chapter V the normal contrast enhanced computed tomographic features of the coelomic cavity of the green iguana, black and white tegu and the bearded dragon are described. 4 cadavers and 4 live animals for each considered species were object of this study. The cadavers were frozen for 24 hours and then cross sectioned at 5mm intervals. The slices have been cleaned with water and photographed on both sides. In order to reduce the duration of the procedure only contrast enhanced CT scans have been performed. The CT scans have been performed in a CC direction. The CT scans have been displayed in a soft tissue and, when appropriate, in a lung window. Individual organs have been recognised and labelled on the anatomical images and then matched on the corresponding CT images. Most of the coelomic organs have been identified in all the considered species. Results provide an atlas of the normal cross sectional and CT features of the coelomic cavity of lizards. In Chapter VI the normal ultrasonographic features of the coelomic cavity of the Boa constrictor, Python molurus, Python curtus and Python regius are described. Moreover, normal reference ultrasonographic measurements of the scent glans, the colonic, gastric and pyloric wall thickness are reported. 46 live snakes (16 Python regius, 10 Python molurus, 12 Python curtus and 8 Boa constrictor) and 23 cadavers (6 Python regius, 4 Python molurus, 10 Python curtus, 3 Boa constrictor) where object of this study. Anatomical studies where performed prior to the beginning of the ultrasonographic studies in order to characterise the normal anatomical features of the above mentioned species. In previous ultrasonographic studies of the coelomic cavity of the Boa constrictor studies a ventral approach on sedated animals was proposed. We have decided to use a lateral approach on unsedated animals. Although, especially in larger animals, the shadowing effect produced by the ribs was evident in some images, most of the coelomic organs (scent glands, hemipenes, cloaca, ureters, colon, small intestine, pylorus, stomach, pancreas, liver, gallbladder and oesophagus) have been recognised. The rate of ultrasonographic recognition of individual organs is reported. Results provide a description of the normal ultrasonographic features of coelomic cavity of boid snakes along with a series of tables matching the gross and cross sectional anatomy with corresponding normal ultrasonographic images. In Chapter VII the technique and the normal features of upper gastro-intestinal examination in ball pythons are described. 10 ball python's cadavers have been dissected and cross sectioned prior to the the beginning of the study in order to characterise the normal features of the intestine in this species.18 healthy ball pythons where object of this study. All animals where not fed for at least 7 days before the beginning of the study. The animals have been divided into three groups (A, B, C). Contrast medium (barium sulphate) at the dose of 25 ml/kg has been administered through an esophageal probe at an increasing concentration (25%, 35% and 45 wt/vol) to three groups. An initial animal (Group A , 25% wt/vol) was used to verify the feasibility and establish a time course for the procedure. Imaging quality was evaluated by 3 investigators who assigned a grading score on the basis of predetermined criteria. Results of present study revealed that the 35% wt/vol concentration of contrast medium provided the best imaging quality. Moreover, three pattern of distribution of the contrast medium in the small intestine, independent from the concentration, have been described.
Negli ultimi anni ofidi e sauri sono diventati sempre più diffusi come animali da compagnia. Questa crescente diffusione ha comportato un aumento della richiesta di servizi veterinari specializzati in questi animali. L’imaging diagnostico spesso è una parte fondamentale dell’indagine clinica. La corretta interpretazione delle immagini diagnostiche implica una conoscenza approfondita dell’anatomia, fisiologia e patologia della specie oggetto dell’indagine clinica. Il confronto tra immagini normali e immagini patologiche spesso è di vitale importanza per una corretta interpretazione delle immagini diagnostiche. Lo scopo di questa tesi di dottorato è quella di fornire degli atlanti che mettano in relazione l’anatomia normale e per sezioni con le corrispondenti immagini radiografiche, tomografiche e ecografiche di alcune delle specie più popolari di ofidi e sauri. Il Capitolo I è riportata una revisione della letteratura corrente sull’imaging in ofidi e sauri. Al momento manca un riferimento univoco su questo argomento e la letteratura presente è spesso frammentaria a volte difficile da reperire. L’obiettivo di questo capitolo, quindi, è quello di fare il punto sullo stato dell’arte della diagnostica per immagini in ofidi e sauri. Molti articoli internazionali riguardanti la radiologia, l’ecografia, la tomografia computerizzata, la risonanza magnetica e altre tecniche di imaging sono stati citati in modo da creare un riferimento utile ai clinici che si occupano di animali esotici. Nel Capitolo II vengono presentati gli obiettivi scientifici e la struttura di questa tesi. L’obiettivo generale è quello di fornire una descrizione dell’anatomia e dell’imaging normale in ofidi e sauri. La prima parte (Capitoli III e IV) è incentrata sul confronto tra la l’anatomia normale e per sezioni della testa alcune specie di ofidi e sauri con i normali aspetti radiografici e tomografici. La seconda parte (Capitoli dal V al VII) è incentrata sull’imaging della cavità celomatica. In questi capitoli sono descritti: gli aspetti normali valutati in tomografia computerizzata della cavità celomatica di alcune specie di sauri, l’ecografia normale in alcune specie di ofidi e il Nel Capitolo III sono descritti i normali aspetti anatomici, radiografici e tomografici della testa del Boa constrictor. Per questo studio sono stati impiegate le teste di 4 cadaveri di Boa constrictor. Utilizzando una combinazione pellicola-casetta ad alta definizione sono state ottenute proiezioni latero-laterali e dorso-ventrali di tutte le teste. L’esame tomografico è stato eseguito in direzione cranio-caudale e latero-laterale con uno spessore di fetta di 1,5mm. Le immagini sono state visualizzate in una finestra da osso. 2 teste sono state dissezionate con un approccio stratigrafico. 2 teste invece sono state congelate per 24 ore a -20°C e poi sezionate in fette di 3mm rispettando il protocollo utilizzato in tomografia computerizzata. Le strutture anatomiche sono state identificate nelle immagini anatomiche e poi accoppiate con le corrispondenti immagini radiografiche e tomografiche. I tessuti ossei sono ben definiti sia nelle immagini radiografiche che tomografiche; i tessuti molli risultano poco definiti in entrambe. Nel Capitolo IV l’anatomia stratigrafica e per sezioni della testa dell’iguana, del tegu e del drago barbuto vengono messi in relazione con il loro normale aspetto radiografico e tomografico. Per realizzare questo studio sono stati usati 4 cadaveri per specie e 6 iguane, 4 tegu e 3 draghi barbuti adulti. Prima di iniziare gli studi di imaging 2 cadaveri per specie sono stati dissezionati con un approccio stratigrafico e 2 sono stati sezionati. Gli studi anatomici sono stati eseguiti con la stessa metodica riportata nel Capitolo III. Gli studi radiografici e tomografici sono stati eseguiti solo sugli animali vivi. Le radiografie sono stata scattate in proiezione latero-laterale e dorso-ventrale. Le scansioni tomografiche sono state effettuate pre e post contrasto scansionando gli animali in direzione cranio-caudale. Le immagini tomografiche sono state quindi visualizzate sia in finestra da tessuti molli che da osso. Le strutture anatomiche sono state individuate prima nelle immagini anatomiche e poi correlate con le corrispondenti immagini radiografiche e tomografiche. Gli studi radiografici hanno permesso di visualizzare in maniera ottimale sia i tessuti duri che i tessuti molli (specialmente nell’iguana). Negli studi tomografici le strutture ossee sono state visualizzate in modo ottimale in tutte le specie. I tessuti molli sono chiaramente delineati solo nell’iguana; nel tegu e nel drago barbuto si riescono a distinguere chiaramente solo gli occhi. Nel Capitolo V i normali aspetti anatomici della cavità celomatica dell’iguana verde, del tegu bianco e nero e del drago barbuto sono messi in relazione con i normali aspetti tomografici di queste specie. Per questo studio sono stati usati 4 cadaveri e 4 animali vivi per specie. I cadaveri sono stati congelati per 24 ore e poi sezionati a intervalli di 5mm. Le fette così ottenute sono state lavate da entrambi i lati e poi fotografate. Per ridurre la durata delle procedure diagnostiche sono state effettuate solo procedure post-contrasto. Le scansioni tomografiche sono state effettuate in direzione cranio-caudale. Le immagini tomografiche sono state visualizzate in finestra da tessuti molli e da polmoni. La maggior parte degli organi celomatici sono stati individuati sia nelle immagini anatomiche che nelle immagini tomografiche. Il risultato di questo lavoro è un atlante degli aspetti anatomici e tomografici normali della cavità celomatica di queste specie di sauri. Nel Capitolo VI vengono descritti gli aspetti ultrasonografici normali della cavità celomatica del Boa constrictor, Python molurus, Python curtus e Python regius. Inoltre vengono fornite le misure ecografiche di riferimento delle scent glands e delle mucose gastica, pilorica e del colon nelle suddette specie. Per questo lavoro sono stati utilizzati 46 serpenti vivi (16 Python regius, 10 Python molurus, 12 Python curtus and 8 Boa constrictor) and 23 cadaveri (6 Python regius, 4 Python molurus, 10 Python curtus, 3 Boa constrictor). Gli studi anatomici sono stati effettuati prima di iniziare gli studi ecografici in modo da caratterizzare i normali aspetti anatomici di queste specie. In un lavoro precedente, nel quale vengono descritti i normali aspetti ecografici del Boa constrictor, viene proposto un approccio ventrale al paziente. In questo studio proponiamo un approccio laterale. In alcune immagini ecografiche i coni d’ombra prodotti dalle coste di questi animali, specialmente nei soggetti di maggiori dimensioni, degradavano leggermente la qualità dell’esame. Nonostante ciò è stato possibile riconoscere la maggior parte degli organi celomatici (scent glands, emipeni, cloaca, ureteri, colon, piccolo e grosso intestino, piloro, stomaco, pancreas, fegato, cistifellea ed esofago). Il numero di animali nei quali i singoli organi sono stati visualizzati è stato riportato. Questo lavoro ha prodotto una descrizione completa degli aspetti ecografici normali in alcune specie di boidi oltre a una serie di tavole che mettono in relazione l’anatomia normale e per sezioni con le corrispondenti immagini ecografiche. Nel Capitolo VII è riportata la tecnica e gli aspetti normali dello studio radiografico dell’esofago, stomaco e piccolo intestino nel Python regius. Per caratterizzare l’aspetto normale del piccolo intestino di questa specie i cadaveri di 10 Python regius sono stati dissezionati prima dei iniziare procedure diagnostiche. Per questo lavoro sono stati utilizzati 18 Python regius. Tutti gli animali utilizzati non sono stati nutriti nella settimana precedente lo studio. Gli animali sono stati divisi in 3 gruppi (A, B, C). Il mezzo di contrasto (bario solfato) è stato somministrato alla dose di 25ml/kg tramite una sonda esofagea a concentrazione crescente (25%, 35%, 45% p/v) nei tre gruppi. Un soggetto appartenente al gruppo A (25% p/v) è stato usato per verificare la fattibilità della procedura e per stabilire una timeline radiografica approssimativa per gli studi successivi. La qualità delle immagini diagnostiche è stata valutata da tre autori in basi a criteri pre-definiti. I risultati di questo studio suggeriscono che la concentrazione ideale di mezzo contrasto per questo tipo di indagine diagnostica è del 35%. Inoltre, sono stati descritti tre pattern di distribuzione del mezzo di contrasto nel piccolo intestino, indipendenti dalla concentrazione.

Review question / Objective: With the development of endoscopic techniques, several diagnostic endoscopy methods are available for the diagnosis of malignant lesions, including magnified pigmented endoscopy and narrow band imaging (NBI).The main goal of endoscopy is to achieve the real-time diagnostic evaluation of the tissue, allowing an accurate assessment comparable to histopathological diagnosis based on structural and cellular heterogeneity to significantly improve the diagnostic rate for cancerous tissues. Endocytoscopy (ECS) is based on ultrahigh magnification endoscopy and has been applied to endoscopy to achieve microscopic observation of gastrointestinal (GI) cells through tissue staining, thus allowing the differentiation of cancerous and noncancerous tissues in real time.To date, ECS observation has been applied to the diagnosis of oesophageal, gastric and colorectal tumours and has shown high sensitivity and specificity.Despite the highly accurate diagnostic capability of this method, the interpretation of the results is highly dependent on the operator's skill level, and it is difficult to train all endoscopists to master all methods quickly. Artificial intelligence (AI)-assisted diagnostic systems have been widely recognized for their high sensitivity and specificity in the diagnosis of GI tumours under general endoscopy. Few studies have explored on ECS for endoscopic tumour identification, and even fewer have explored ECS-based AI in the endoscopic identification of GI tumours, all of which have reached different conclusions. Therefore, we aimed to investigate the value of ECS-based AI in detecting GI tumour to provide evidence for its clinical application.