This thesis was carried out at the "Analysis Laboratory Radiological Advanced" (LARA), in collaboration with the "Department of Bioengineering" of Politecnico di Milano and the Department of "Diagnostic Imaging and Radiotherapy "of the" Fondazione IRCCS National Cancer Institute "(INT). The aim of this work was the characterization and evaluation of nasopharyngeal cancer (NPC) and the limph nodal tissue associated with the pathology through two specific techniques of MRI: Diffusion Weighted Imaging (DWI) and Dynamic Contrast Enhanced (DCE). The DWI was introduced to study the microstructure tissue with the measurement of water diffusivity, whose variation is related to the pathological tissues, whereas the DCE-MRI studies the dynamics of the capillary network that supplies the tumor and in particular the permeability of blood vessels that nourish it. The tumor and lymph nodal analysis was carried out on a sample of 22 patients affected by NPC, choosing for each patient MR examinations only to "first survey", which are important for the assessment of cancer staging. For the DWI technique, our research has an acquisition protocol consisting of MR anatomical T1-weighted sequences before and after contrast medium (Gd) injection, T2 Turbo Spin Echo (TSE) and DWI sequences at different b-values. The DICOM images were reassembled and resampled with isotropic 0.5 mm spatial resolution. Coregistration was implemented using the volume T1-Gd as a reference, using two multiresolution rigid transformations, merging head and neck volumes, and a multiresolution non-rigid transformation. 8 volumes co-registered have been obtained for each session. The volumes have been used for the location of regions of interest (ROI) drawn with the help of an experienced radiologist and the assistance of a graphical user interface built in-house. As regards the technique DCE-MRI, a session MR ,composed of T1-T2 TSE sequences and VIBE-spoiled gradient echo (sGRE) sequences for the evaluation of vascular dynamics has been provided. The identification and characterization of cancer and lymph nodes in cases of NPC was possible by the use of a dedicated software 3Dnet SuiteTM of Biotronics3D, clinically validated by the Institute of Cancer Research and the Royal Marsden Hospital in London, in this case the ROI have been drawn with the aid of the radiologist. Data analysis, supported by statistical analysis, showed that, comparing two by two the three different tissue classes (tumor, lymph node and lymph node capsule), there were statistically significant differences among the tissues both at microstructural level (average diffusivity, ADC) and at hemodynamic level (permeability , Ktrans and IAUGC). As for the DWI, this work reveals a significant difference of the ADC values between the capsule and the tumor, probably indicating a different cellularity between the two tissues. Even the analysis of perfusion revealed a significant difference, in particular between the primary tumor and its derivatives (lymph node capsule): the parameters of the endothelial wall permeability Ktrans and IAUGC showed a greater perfusion of lymph node areas, as their normal physiology suggests. The work supports the conclusion that the conjunction of normal clinical MR imaging with the two advanced techniques DWI and DCE-MRI allows the identification of suitable parameters for the characterization of the microstructural and microvascular tissue, suggesting the evaluation of a suitable therapeutic treatment ,and also the prediction of the NPC cancer staging before the biopsy.
Il presente lavoro di tesi magistrale è stato svolto all’interno del “Laboratorio di Analisi Radiologiche Avanzate” (LARA), nato da una collaborazione con il “Dipartimento di Bioingegneria” del Politecnico di Milano e il Dipartimento di “Diagnostica per Immagini e Radioterapia” della “Fondazione IRCCS Istituto Nazionale dei Tumori” (INT). Lo studio ha avuto come scopo la caratterizzazione e la valutazione del tumore del rinofaringe (NPC) e del tessuto lifonodale associato alla patologia tramite due tecniche specifiche di risonanza magnetica Diffusion Weighted Imaging (DWI) e Dynamic Contrast Enhanced (DCE). La DWI è stata utilizzata per studiare la microstruttura tissutale e la variazione correlata ai tessuti patologici, mentre, la DCE-MRI è utilizzata per studiare la dinamica della rete capillare che irrora il tumore ed in particolare la permeabilità dei vasi sanguigni che lo nutrono. L’analisi tumorale e linfonodale è stata svolta su un campione di 22 soggetti affetti da carcinoma rinofaringeo, scegliendo per ogni paziente solo esami MR a “prima indagine”, importanti per la valutazione dello staging del carcinoma. Lo studio di ricerca ha previsto, per la tecnica DWI, un protocollo di acquisizione MR composto da sequenze anatomiche T1-pesate pre e post iniezione di mezzo di contrasto (Gd), sequenze T2 Turbo Spin Echo (TSE) e sequenze DWI a differenti valori di b. Le immagini DICOM sono state ricollocate spazialmente e ricampionate con una risoluzione isotropica di 0.5mm. La coregistrazione è stata implementata, usando il volume T1-Gd come riferimento, tramite due trasformazioni rigide multirisoluzione, l'unione dei volumi testa e collo, e una trasformazione non rigida multirisoluzione. Per ogni sessione si sono ottenuti 8 volumi coregistrati. Ciascuno dei volumi è stato utilizzato per la localizzazione delle regioni d’interesse (ROI) tracciate tramite l’aiuto di un radiologo esperto con l’assistenza di un’interfaccia grafica realizzata in-house. Per quanto riguarda la tecnica DCE-MRI, è stata prevista una sessione MR composta da sequenze T1-T2 TSE, VIBE e sequenze spoiled-Gradient Echo (sGRE) per la valutazione della dinamica vascolare. L'identificazione e la caratterizzazione del carcinoma e dei linfonodi nei casi di NPC è stata permessa dall’uso di un software dedicato 3Dnet SuiteTM di Biotronics3D, clinicamente validato dall’Istituto di Ricerca dei Tumori e dal Royal Marsden Hospital di Londra, anche in questo caso le ROI sono state tracciate con l’aiuto del radiologo. Dall’analisi statistica effettuata sui dati acquisiti, confrontando le tre diverse classi tissutali (tumore, linfonodo e capsula linfonodale), sono emerse differenze statisticamente significative tra i tessuti sia a livello microstrutturale (diffusività media, ADC) che emodinamico (permeabilità, Ktrans e IAUGC). Per ciò che concerne la DWI, i risultati ottenuti in questo studio mostrano una differenza significativa dei valori di ADC tra capsula e tumore probabilmente indicando una differente cellularità tra i due tessuti. Anche nell’analisi di perfusione sono emerse differenze significative, in particolare tra il tumore primario e i derivati (linfonodo e capsula): i parametri di permeabilità della parete endoteliale Ktrans e IAUGC hanno evidenziato una maggior perfusione delle zone linfonodali, come suggerito dalla loro normale fisiologia. Il lavoro svolto consente di concludere che la possibilità di affiancare al normale imaging clinico MR con le due tecniche avanzate DWI e DCE-MRI consente di identificare parametri idonei per la caratterizzazione microstrutturale e microvascolare dei tessuti suggerendo la valutazione di un trattamento terapeutico adeguato o, in prospettiva, di prevedere la stadiazione del carcinoma NPC precedentemente alla biopsia.
Caratterizzazione e differenziazione dei tessuti linfonodale e rinofaringeo con tecniche DWI e DCE-MRI
SARCINA, ANNUNZIATA STEFANIA
2011/2012
Abstract
This thesis was carried out at the "Analysis Laboratory Radiological Advanced" (LARA), in collaboration with the "Department of Bioengineering" of Politecnico di Milano and the Department of "Diagnostic Imaging and Radiotherapy "of the" Fondazione IRCCS National Cancer Institute "(INT). The aim of this work was the characterization and evaluation of nasopharyngeal cancer (NPC) and the limph nodal tissue associated with the pathology through two specific techniques of MRI: Diffusion Weighted Imaging (DWI) and Dynamic Contrast Enhanced (DCE). The DWI was introduced to study the microstructure tissue with the measurement of water diffusivity, whose variation is related to the pathological tissues, whereas the DCE-MRI studies the dynamics of the capillary network that supplies the tumor and in particular the permeability of blood vessels that nourish it. The tumor and lymph nodal analysis was carried out on a sample of 22 patients affected by NPC, choosing for each patient MR examinations only to "first survey", which are important for the assessment of cancer staging. For the DWI technique, our research has an acquisition protocol consisting of MR anatomical T1-weighted sequences before and after contrast medium (Gd) injection, T2 Turbo Spin Echo (TSE) and DWI sequences at different b-values. The DICOM images were reassembled and resampled with isotropic 0.5 mm spatial resolution. Coregistration was implemented using the volume T1-Gd as a reference, using two multiresolution rigid transformations, merging head and neck volumes, and a multiresolution non-rigid transformation. 8 volumes co-registered have been obtained for each session. The volumes have been used for the location of regions of interest (ROI) drawn with the help of an experienced radiologist and the assistance of a graphical user interface built in-house. As regards the technique DCE-MRI, a session MR ,composed of T1-T2 TSE sequences and VIBE-spoiled gradient echo (sGRE) sequences for the evaluation of vascular dynamics has been provided. The identification and characterization of cancer and lymph nodes in cases of NPC was possible by the use of a dedicated software 3Dnet SuiteTM of Biotronics3D, clinically validated by the Institute of Cancer Research and the Royal Marsden Hospital in London, in this case the ROI have been drawn with the aid of the radiologist. Data analysis, supported by statistical analysis, showed that, comparing two by two the three different tissue classes (tumor, lymph node and lymph node capsule), there were statistically significant differences among the tissues both at microstructural level (average diffusivity, ADC) and at hemodynamic level (permeability , Ktrans and IAUGC). As for the DWI, this work reveals a significant difference of the ADC values between the capsule and the tumor, probably indicating a different cellularity between the two tissues. Even the analysis of perfusion revealed a significant difference, in particular between the primary tumor and its derivatives (lymph node capsule): the parameters of the endothelial wall permeability Ktrans and IAUGC showed a greater perfusion of lymph node areas, as their normal physiology suggests. The work supports the conclusion that the conjunction of normal clinical MR imaging with the two advanced techniques DWI and DCE-MRI allows the identification of suitable parameters for the characterization of the microstructural and microvascular tissue, suggesting the evaluation of a suitable therapeutic treatment ,and also the prediction of the NPC cancer staging before the biopsy.| File | Dimensione | Formato | |
|---|---|---|---|
|
2012_10_SARCINA.pdf
non accessibile
Descrizione: Testo della tesi
Dimensione
12.18 MB
Formato
Adobe PDF
|
12.18 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/66461