Original scientific paper
https://doi.org/10.3325/cmj.2015.56.460
Apparent diffusion coefficient measurement covering complete tumor area better predicts rectal cancer response to neoadjuvant chemoradiotherapy
Ivana Blažić
; Clinical Hospital Centre Zemun, Belgrade, Serbia
Ružica Maksimović
; Clinical Centre of Serbia, Centre for Radiology and MagneticResonance Imaging, Belgrade, Serbia
Milan Gajić
; Institute for Medical Statistics and Informatics, Belgrade, Serbia
Đorđije Šaranović
; Clinical Centre of Serbia, Centre for Radiology and MagneticResonance Imaging, Belgrade, Serbia
Abstract
Aim To determine the impact of two apparent diffusion
coefficient (ADC) measurement techniques on diffusionweighted
magnetic resonance images (DW MRI) on the
assessment of rectal cancer response to neoadjuvant
chemoradiotherapy (CRT).
Methods ADC values were measured prospectively with
two different techniques – the first, which measures ADCs
in the most cellular tumor parts, and the second, which
measures the entire tumor area, in 58 patients with locally
advanced rectal cancer on pre-CRT and post-CRT image
sets. Areas under the receiver operating characteristic
curves (AUCs) and parameters of diagnostic accuracy were
calculated for pre- and post-CRT ADC values and numeric
and percent ADC change for each technique to determine
their performance in tumor response evaluation using histopathological
tumor-regression grade as the reference
standard.
Results The second technique yielded higher AUCs
(0.935 vs 0.704, P < 0.001), percent-change (0.828 vs 0.636,
P < 0.001), and numeric-change (0.866 vs 0.653, P < 0.001)
than the first technique for post-CRT ADC. Accuracies
for post-CRT ADC assessment were 62% for the first and
88% for the second technique (cut-off values: 0.98 and
1.29 × 10−3 mm2/s, respectively) and for ADC change assessment,
both numeric and percent, 59% and 74%, respectively
(cut-off values: increase of 0.18 and 0.28 × 10−3
mm2/s; increase of 24% and 37%, respectively).
Conclusions The type of measurement technique significantly
affected ADC results. ADC measurements covering
a larger area better predicted tumor response to therapy.
Post-CRT ADCs, regardless of the measurement technique,
and numeric ADC change measured in the whole tumor
volume accurately identified non-complete responders.
Post-CRT ADCs measured in the entire tumor area yielded
the highest accuracy level in tumor response evaluation.
Keywords
Hrčak ID:
151740
URI
Publication date:
15.10.2015.
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