Postgraduate Thesis: Quantitative multiparametric imaging for the evaluation of nasopharyngeal carcinoma using PET and DCE-MRI

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Title	Quantitative multiparametric imaging for the evaluation of nasopharyngeal carcinoma using PET and DCE-MRI
Authors	Huang, Bingsheng 黄炳升
Issue Date	2012
Publisher	The University of Hong Kong (Pokfulam, Hong Kong)
Abstract	Nasopharyngeal carcinoma (NPC) is an aggressive head and neck cancer ranked as the 5th most common in Hong Kong. We aimed to study the role of dynamic contrast-enhanced MRI (DCE-MRI) and dynamic 2-deoxy-2-[fluorine-18]fluoro -D-glucose positron emission tomography (FDG-PET) for characterizing NPC tumors in newly-diagnosed patients, and to quantitatively evaluate the intratumoral heterogeneity of NPC. In Chapter 2 we employed semi-quantitative analysis of DCE-MRI to study the dynamic enhancement pattern by analyzing the time-intensity curves in 25 NPC patients. Our findings suggested that high blood flow caused a high initial intensity enhancement rate (ER), and that neovasculature due to tumor angiogenesis in tumors of larger volume or higher T-stage caused more accumulation of contrast agent which can be detected by DCE-MRI. PET and semi-quantitative DCE-MRI parameters were not correlated and may reflect different physiological/molecular processes in the microenvironment of NPC tumor. However the major limitation of semi-quantitative analysis was that the physiological correlates of these parameters were unclear. In Chapter 3 we applied quantitative analysis of DCE-MRI to study the permeability and perfusion characteristics in the same cohort as in Chapter 2. Our findings implied that the permeability may be high compared to blood flow in NPC tumor. We also observed significant correlations between iAUC (the initial area under the time-intensity curve) by semi-quantitative analysis and ve (the volume fraction of extravascular extracellular space) by quantitative analysis, and between the two rate constants (kep’s) from these two methods, which showed that semi-quantitative analysis was a feasible alternative in reflecting the physiological characteristics of NPC. However, we did not observe any significant correlation between PET and DCE-MRI quantitative parameters, also suggesting that PET and DCE-MRI reflected different physiological information in NPC. In Chapter 4 we applied dynamic PET scan to study the glucose metabolism in 18 NPC tumors (16 included in DCE-MRI cohort). Our findings showed that the overall FDG uptake was mainly composed of the FDG in tissue compartment (Ki), which was governed by the phosphorylation (k3) but not the transport of FDG (K1). This finding may further indicate a potential role of the phosphorylation rate k3 in NPC. Dynamic PET parameters did not correlate with DCE-MRI, indicating that the two modalities reflect different molecular information in NPC. In Chapter 5, intratumoral heterogeneity in NPC tumors of 40 patients was studied using 18F-FDG PET scan. Our findings showed that as tumors grew to a larger volume and higher T-stage, they showed more heterogeneous glucose metabolism. It was found that more heterogeneous tumor was associated with worse disease-free survival, indicating that tumor metabolic heterogeneity may play an important role for NPC patient prognosis. To summarize, these results showed that DCE-MRI and dynamic PET improved our understanding about the physiological/molecular process of NPC, and, these two modalities reflected different physiological information in the microenvironment of NPC tumors. This indicated that the relationship between supply of nutrients such as glucose and blood flow/permeability is complex and not directly related. Moreover, intratumoral heterogeneity by PET scan was also of importance in prognostication.
Advisors	Khong, PL
Degree	Doctor of Philosophy
Subject	Nasopharynx - Cancer - Magnetic resonance imaging. Nasopharynx - Cancer - Tomography.
Dept/Program	Diagnostic Radiology

DC Field	Value
dc.contributor.advisor	Khong, PL
dc.contributor.author	Huang, Bingsheng
dc.contributor.author	黄炳升
dc.date.hkucongregation	2012
dc.date.issued	2012
dc.description.abstract	Nasopharyngeal carcinoma (NPC) is an aggressive head and neck cancer ranked as the 5th most common in Hong Kong. We aimed to study the role of dynamic contrast-enhanced MRI (DCE-MRI) and dynamic 2-deoxy-2-[fluorine-18]fluoro -D-glucose positron emission tomography (FDG-PET) for characterizing NPC tumors in newly-diagnosed patients, and to quantitatively evaluate the intratumoral heterogeneity of NPC. In Chapter 2 we employed semi-quantitative analysis of DCE-MRI to study the dynamic enhancement pattern by analyzing the time-intensity curves in 25 NPC patients. Our findings suggested that high blood flow caused a high initial intensity enhancement rate (ER), and that neovasculature due to tumor angiogenesis in tumors of larger volume or higher T-stage caused more accumulation of contrast agent which can be detected by DCE-MRI. PET and semi-quantitative DCE-MRI parameters were not correlated and may reflect different physiological/molecular processes in the microenvironment of NPC tumor. However the major limitation of semi-quantitative analysis was that the physiological correlates of these parameters were unclear. In Chapter 3 we applied quantitative analysis of DCE-MRI to study the permeability and perfusion characteristics in the same cohort as in Chapter 2. Our findings implied that the permeability may be high compared to blood flow in NPC tumor. We also observed significant correlations between iAUC (the initial area under the time-intensity curve) by semi-quantitative analysis and ve (the volume fraction of extravascular extracellular space) by quantitative analysis, and between the two rate constants (kep’s) from these two methods, which showed that semi-quantitative analysis was a feasible alternative in reflecting the physiological characteristics of NPC. However, we did not observe any significant correlation between PET and DCE-MRI quantitative parameters, also suggesting that PET and DCE-MRI reflected different physiological information in NPC. In Chapter 4 we applied dynamic PET scan to study the glucose metabolism in 18 NPC tumors (16 included in DCE-MRI cohort). Our findings showed that the overall FDG uptake was mainly composed of the FDG in tissue compartment (Ki), which was governed by the phosphorylation (k3) but not the transport of FDG (K1). This finding may further indicate a potential role of the phosphorylation rate k3 in NPC. Dynamic PET parameters did not correlate with DCE-MRI, indicating that the two modalities reflect different molecular information in NPC. In Chapter 5, intratumoral heterogeneity in NPC tumors of 40 patients was studied using 18F-FDG PET scan. Our findings showed that as tumors grew to a larger volume and higher T-stage, they showed more heterogeneous glucose metabolism. It was found that more heterogeneous tumor was associated with worse disease-free survival, indicating that tumor metabolic heterogeneity may play an important role for NPC patient prognosis. To summarize, these results showed that DCE-MRI and dynamic PET improved our understanding about the physiological/molecular process of NPC, and, these two modalities reflected different physiological information in the microenvironment of NPC tumors. This indicated that the relationship between supply of nutrients such as glucose and blood flow/permeability is complex and not directly related. Moreover, intratumoral heterogeneity by PET scan was also of importance in prognostication.
dc.description.nature	published_or_final_version
dc.description.thesisdiscipline	Diagnostic Radiology
dc.description.thesislevel	doctoral
dc.description.thesisname	Doctor of Philosophy
dc.identifier.hkul	b4786958
dc.language	eng
dc.publisher	The University of Hong Kong (Pokfulam, Hong Kong)
dc.relation.ispartof	HKU Theses Online (HKUTO)
dc.rights	The author retains all proprietary rights, (such as patent rights) and the right to use in future works.
dc.rights	Creative Commons: Attribution 3.0 Hong Kong License
dc.source.uri	http://hub.hku.hk/bib/B47869586
dc.subject.lcsh	Nasopharynx - Cancer - Magnetic resonance imaging.
dc.subject.lcsh	Nasopharynx - Cancer - Tomography.
dc.title	Quantitative multiparametric imaging for the evaluation of nasopharyngeal carcinoma using PET and DCE-MRI
dc.type	PG_Thesis

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as the 5th most common in Hong Kong. We aimed to study the role of dynamic

contrast-enhanced MRI (DCE-MRI) and dynamic 2-deoxy-2-[fluorine-18]fluoro

-D-glucose positron emission tomography (FDG-PET) for characterizing NPC

tumors in newly-diagnosed patients, and to quantitatively evaluate the

intratumoral heterogeneity of NPC.

In Chapter 2 we employed semi-quantitative analysis of DCE-MRI to study the

dynamic enhancement pattern by analyzing the time-intensity curves in 25 NPC

patients. Our findings suggested that high blood flow caused a high initial

intensity enhancement rate (ER), and that neovasculature due to tumor

angiogenesis in tumors of larger volume or higher T-stage caused more

accumulation of contrast agent which can be detected by DCE-MRI. PET and

semi-quantitative DCE-MRI parameters were not correlated and may reflect

different physiological/molecular processes in the microenvironment of NPC

tumor. However the major limitation of semi-quantitative analysis was that the

physiological correlates of these parameters were unclear.

In Chapter 3 we applied quantitative analysis of DCE-MRI to study the

permeability and perfusion characteristics in the same cohort as in Chapter 2.

Our findings implied that the permeability may be high compared to blood flow

in NPC tumor. We also observed significant correlations between iAUC (the

initial area under the time-intensity curve) by semi-quantitative analysis and ve

(the volume fraction of extravascular extracellular space) by quantitative analysis,

and between the two rate constants (kep&#8217;s) from these two methods, which

showed that semi-quantitative analysis was a feasible alternative in reflecting the

physiological characteristics of NPC. However, we did not observe any

significant correlation between PET and DCE-MRI quantitative parameters, also

suggesting that PET and DCE-MRI reflected different physiological information

in NPC.

In Chapter 4 we applied dynamic PET scan to study the glucose metabolism in

18 NPC tumors (16 included in DCE-MRI cohort). Our findings showed that

the overall FDG uptake was mainly composed of the FDG in tissue compartment

(Ki), which was governed by the phosphorylation (k3) but not the transport of

FDG (K1). This finding may further indicate a potential role of the

phosphorylation rate k3 in NPC. Dynamic PET parameters did not correlate

with DCE-MRI, indicating that the two modalities reflect different molecular

information in NPC.

In Chapter 5, intratumoral heterogeneity in NPC tumors of 40 patients was

studied using 18F-FDG PET scan. Our findings showed that as tumors grew to

a larger volume and higher T-stage, they showed more heterogeneous glucose

metabolism. It was found that more heterogeneous tumor was associated with

worse disease-free survival, indicating that tumor metabolic heterogeneity may

play an important role for NPC patient prognosis.

To summarize, these results showed that DCE-MRI and dynamic PET improved

our understanding about the physiological/molecular process of NPC, and, these

two modalities reflected different physiological information in the

microenvironment of NPC tumors. This indicated that the relationship between

supply of nutrients such as glucose and blood flow/permeability is complex and

not directly related. Moreover, intratumoral heterogeneity by PET scan was

also of importance in prognostication.</description.abstract><language>eng</language><publisher>The University of Hong Kong (Pokfulam, Hong Kong)</publisher><relation.ispartof>HKU Theses Online (HKUTO)</relation.ispartof><rights>The author retains all proprietary rights, (such as patent rights) and the right to use in future works.</rights><rights>Creative Commons: Attribution 3.0 Hong Kong License</rights><source.uri>http://hub.hku.hk/bib/B47869586</source.uri><subject.lcsh>Nasopharynx - Cancer - Magnetic resonance imaging.</subject.lcsh><subject.lcsh>Nasopharynx - Cancer - Tomography.</subject.lcsh><title>Quantitative multiparametric imaging for the evaluation of nasopharyngeal carcinoma using PET and DCE-MRI</title><type>PG_Thesis</type><identifier.hkul>b4786958</identifier.hkul><description.thesisname>Doctor of Philosophy</description.thesisname><description.thesislevel>doctoral</description.thesislevel><description.thesisdiscipline>Diagnostic Radiology</description.thesisdiscipline><description.nature>published_or_final_version</description.nature><date.hkucongregation>2012</date.hkucongregation><bitstream.url>http://hub.hku.hk/bitstream/10722/161536/1/FullText.pdf</bitstream.url></item>