Synopsis
This study is to
investigate the diagnostic utility of fractional anisotropy(FA) and apparent
diffusion coefficient(ADC) values of diffusion tensor imaging(DTI) to differentiate and classify abnormal signal
nodules in prostate transition zone. Eighty-four patients were included in our study and divided
into 5 groups: BPH,Gleason score(GS)≤6,GS＝7,GS＝8,GS≥9,measured FA and ADC of the
region of interest, using one-way ANOVA to compare the difference among groups. There
was significant statistical
difference between the groups of FA and ADC values(F＝20.986,P＝0.000; F＝26.560,P＝0.000).Comparison among five groups: just BPH
had significant statistical difference(P＝0.000) with other four groups. The FA and ADC values of DTI had higher
value for distinguishing benign and malignant nodules, but no obvious
advantages in the further classification.Purpose
The abnormal signal nodules in prostate transition zone(TZ) is pretty common among older men. The prostate functional imaging has high resolution and precision in time and space domain, which helped us to detect these lesions easily,
1 but how to distinguish lesions between benign and malignant Is still a difficult task in MRI imaging research.
2DTI is one of the best techniques of MRI, so our study is to investigate the diagnostic utility of FA and ADC values of DTI in patients with nodules in prostate transition zone.
Methods
Fifty-four TZ-PCa and thirty BPH cases with histopathology diagnosis using ultrasound guided systemic biopsy, were included in our retrospective study. All the patients were divided into 5 groups: BPH、Gleason score (GS)≤6、GS＝7、GS＝8、GS≥9, which based on Gleason system. All patients performed on a 3.0T MRI scaner. The FA and ADC values of the region of interest were respectively measured, using Kolmogorov_Smirnov and Levene test to check up the datas of all groups with normality and homogeneity of variance , using one-way ANOVA to compare the difference between groups and using LSD/DunnettT3 for the paired comparison.
Results
The mean FA values of the 5 groups were 150.52±29.63、222.71±29.04、208.25±45.53、238.91±39.17、237.44±46.90,respectively, and there was statistical difference among the five groups(
F＝20.986,
P＝0.000); comparison among groups: BPH with other four groups and GS＝7 with GS＝8 had statistical difference(
P＝0.000、
P＝0.014). The mean ADC values(×10
-6mm
2/s) of the five groups were 1606.11±234.64、791.67±173.12、848.21±191.69、783.01±118.62、748.96±123.02, respectively and there was statistical difference among the groups(
F＝26.560,
P＝0.000);comparison among groups: just BPH with other four groups had statistical difference(
P＝0.000)．
Discussion
With the development of
higher magnetic field systems and parallel imaging technology, DTI has also
been applied for some of the abdominal organs, especially the prostate.
3, 4ADC value represent the degree of restricted diffusion of water molecules and
FA value represent the fractional anisotropy of water molecules movement. To
our knowledge: the ADC value in BPH is significantly higher than
malignant groups, correspondingly, and the FA value is significantly
slower in BPH group. That may
because the increased amount of cell membranes and intracellular viscosity, as
well as significantly decreased extracellular space in malignant lesions, resulting
the increase of directionality of water diffusion within each pixel of DTI, so a
sustained increase in FA;
5 and also because of disordered arrangement of malignant cells, water molecules
obviously limited, so decreased in ADC. But, the difference among GS≤6、GS＝7、GS＝8 and GS≥9 groups is very small,
the reasons need to be further studied.
Conclusions
The FA and ADC values of diffusion tensor
imaging had higher
value for distinguishing benign and malignant nodules, but no obvious
advantages in the further classification.
Acknowledgements
The authors would like to thank Dr. MingDeng and our team for their support and help in this study. References
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