Assessment of Early Response to Lung Cancer Chemotherapy by Semiquantitative Analysis of Dynamic Contrast-Enhanced MRI

Objective. To evaluate the early chemotherapy response in patients with lung cancer using semiquantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Methods. Twenty-two patients with lung cancer treated with chemotherapy were subjected to DCE-MRI at two time points: before starting treatment and after one week of therapy. The image data were collected by DCE-MRI, and the semiquantitative parameters including positive enhancement integral (PEI), signal enhancement ratio (SER), maximum slope of increase (MSI), and time to peak (TTP) were calculated. After chemotherapy, the parameters and relevant variations between the responders and nonresponders were compared with Mann–Whitney <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi>U</a:mi> </a:math> tests. Student’s <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>t</c:mi> </c:math> -test for paired samples was used to evaluate the temporal changes between pre- and posttreatment images. Results. The patients were categorized as 13 responders and 9 nonresponders based on the tumor response evaluation. After chemotherapy, the PEI, SER, and MSI were significantly increased in responders compared with the pretreatment values ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mi>P</e:mi> <e:mo><</e:mo> <e:mn>0.05</e:mn> </e:math> ), while no obvious decrease in TTP was observed ( <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"> <g:mi>P</g:mi> <g:mo>></g:mo> <g:mn>0.05</g:mn> </g:math> ). However, 9 nonresponders showed no significant changes in PEI, SER, MSI, and TTP values, as compared with those of pretreatment ( <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" id="M5"> <i:mi>P</i:mi> <i:mo>></i:mo> <i:mn>0.05</i:mn> </i:math> ). Moreover, the increase of PEI was more dramatically in responders than in nonresponders ( <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" id="M6"> <k:mi>P</k:mi> <k:mo><</k:mo> <k:mn>0.05</k:mn> </k:math> ), but no significantly differences were observed in SER, MSI, and TTP ( <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" id="M7"> <m:mi>P</m:mi> <m:mo>></m:mo> <m:mn>0.05</m:mn> </m:math> ). Conclusion. Semiquantitative analysis of DCE-MRI could provide a reliable noninvasive method for assessing early chemotherapy response in lung cancer patients.