Volume 29, Issue 6 (9-2022)
RJMS 2022, 29(6): 115-122 |
Back to browse issues page
Research code: 97117
Ethics code: IR.BHN.REC.1396.09
Clinical trials code: 97117
Download citation:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:
Abedi I, Abdi N, Naserpour M, Rabbani M. Evaluation of the Relationship between Quantitative Apparent Diffusion Coefficient (ADC) Values in Diffusion-Weighted Images of the Prostate with Glisson Score Values in Pathology Specimens after Prostatectomy. RJMS 2022; 29 (6) :115-122
URL: http://rjms.iums.ac.ir/article-1-7101-en.html
URL: http://rjms.iums.ac.ir/article-1-7101-en.html
Assistant Professor, Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran , i.abedi@med.mui.ac.ir
Abstract: (1085 Views)
Background & Aims: Prostate cancer is the most common malignancy in men and the second leading cause of death in all countries of the world. According to the US statistics, about 27% of men in the United States were diagnosed with prostate cancer in 2014, and 10% will die of cancer. Over the past decades, prostate cancer management has reached a point where the degree, stage, and location of cancer determine the type of treatment. Treatment for prostate cancer depends on the spread of cancer at the time of diagnosis. Several clinical trials, including the digital rectal examination (DRE), biochemistry such as prostate-specific Antigen (PSA), and pathology such as ultrasound-guided biopsy (TRUS) are used to assess the size and spread of prostate cancer. However, these tests alone are not enough and reliable to diagnose and stage prostate cancer. In addition to the above methods, there are extensive imaging techniques for the diagnosis and staging of prostate tumors. Initially, CT scans were used for staging, but due to the inherent weakness of CT scans in differentiating prostate disease, MRI and ultrasound were used to diagnose and determine the of stage prostate cancer. Although, the standard method for diagnosing and staging prostate cancer is sampling and determining the Gleason index. In this study, the relationship between Gleason score as a standard method in patients with prostate cancer was compared with the parameters extracted from Diffusion-weighted imaging (DWI). In the DWI method, based on the diffusion of water molecules among intracellular molecules, a parameter called the apparent diffusion coefficient (ADC) is determined in the images and can provide precise contrast to differentiate tumor cells from healthy cells. Sensitivity to the diffusion of water molecules is defined by the gradient factor b (b-value) in s / mm2. This factor indicates the intensity and time of applying gradients to produce diffusion-weighted images. The higher b-value, the stronger effect of the diffusion of water molecules and results in better contrast, greater propagation and lower T2 shine-through effect, but a lower signal-to-noise ratio and a higher sensitivity artifact. Magnetic Resonance Imaging (MRI) provides information on the biological behavior of prostate cancer tissue in diffusion weighted (DW) MR images. The diffusion rate measured by DWI is related to the average path length traveled by water molecules so that the longer path leads to an increase in ADC. The three-dimensional diffusion of water molecules into the tissue is not random due to the presence of cell membrane impedance. Also in tissues with high cell density, increasing cell membrane may significantly inhibit the diffusion of intercellular water molecules and reduce the diffusion pathway and hence reduce ADC. Therefore, this parameter can indirectly provide information about tissue cells. The anatomical structure of normal prostate tissue consists of a glandular component associated with stroma tissue. Water molecules are easily diffused into the glandular component of prostate tissue. But as cancer becomes more distinct, the cell density increases, and the glandular structure becomes unrecognizable.
Methods: This fundamental study was performed on 90 patients with prostate cancer, according to McDonald's criteria, who were referred to Shafa Imaging Center in Isfahan, from March 2020 to January 2021. First, the informed consent form was obtained from all patients and then they participated in the study. In this study, patients were first referred to the MRI imaging department and routine MRI protocols were performed on them. Then, in order to evaluate the accuracy of the MRI-diffusion imaging method in comparison with the surgical and pathological results of patients and also to determine the optimal value of the resulting parameters, this sequence was performed on patients to evaluate the extent of tumor invasion. Free-breathing DW MR axial images were obtained using Siemens Avanto system 1.5 Tesla (with b-values equal to 0, 1000, 1500, and 2000 mm2 / s). The European Society of Urogenital Radiology (ESUR) recommends a b-value in the range of 800-1000 mm2 / s for prostate imaging. ROIs were plotted independently on ADC maps. To measure ADC in prostate cancer, tumor areas on T2W images were used to measure ADC, which accounted for a total of 24 ADC measurements in all three diffusion gradients for each patient. ADC values were measured by inserting ROI with an average area of 30 mm2. Using Medcalc software version 15 with a 95% confidence level, the indicators of sensitivity, specificity, accuracy, threshold, positive, and negative predictive value were calculated.
Results: The results showed that in 6 patients with Gleason score 6, the mean value of ADC using 32 ROIs (Region of Interests) was 0.982 ± 0.909 SD s/mm2. In 9 patients with Gleason score 7, the mean ADC value using 52 ROIs was 0.961 ± 0.806 SD s/mm2. In 6 patients with Gleason score 8, the mean ADC value using 52 ROIs was 0.924 ± 0.786 SD s/mm2. In 4 patients with Gleason score 9, the mean ADC value using 24 ROIs was 0.812 ± 0.726 SD s/mm2. Pearson correlation analysis showed a significant negative correlation between Gleason score and ADC measurements (r = -0.926, P = 0.01).
Conclusion: According to the guidelines of the European association of urology in 2013, the main tools for diagnosing prostate cancer include DRE (Digital Rectal Examination), PSA (Prostate Specific Antigen) and TRUS (Trans-Rectal Ultrasonography)-guided biopsy. Prostate cancer is often multifocal. It is generally accepted that GS determines the prognosis, the lesion with the highest GS has the weakest prognosis. The correlation of imaging with histopathology is very important for the validation and creation of new imaging biomarkers. In particular, accurate correlation allows to analyze relationships between quantitative MRI-based parameters and histopathology, and allows to evaluate the accuracy of imaging in tumor examination. The main limitation of previous studies was the unreliability of the amount of GS obtained from biopsy and problems in determining the exact location of the tumor on MRI. To overcome this limitation, prostatectomy specimens were used for the image and GS communication in this study. The results showed that there was a significant negative relationship between ADC values calculated from DW images and GS of prostate cancer obtained from a prostatectomy sample.
Methods: This fundamental study was performed on 90 patients with prostate cancer, according to McDonald's criteria, who were referred to Shafa Imaging Center in Isfahan, from March 2020 to January 2021. First, the informed consent form was obtained from all patients and then they participated in the study. In this study, patients were first referred to the MRI imaging department and routine MRI protocols were performed on them. Then, in order to evaluate the accuracy of the MRI-diffusion imaging method in comparison with the surgical and pathological results of patients and also to determine the optimal value of the resulting parameters, this sequence was performed on patients to evaluate the extent of tumor invasion. Free-breathing DW MR axial images were obtained using Siemens Avanto system 1.5 Tesla (with b-values equal to 0, 1000, 1500, and 2000 mm2 / s). The European Society of Urogenital Radiology (ESUR) recommends a b-value in the range of 800-1000 mm2 / s for prostate imaging. ROIs were plotted independently on ADC maps. To measure ADC in prostate cancer, tumor areas on T2W images were used to measure ADC, which accounted for a total of 24 ADC measurements in all three diffusion gradients for each patient. ADC values were measured by inserting ROI with an average area of 30 mm2. Using Medcalc software version 15 with a 95% confidence level, the indicators of sensitivity, specificity, accuracy, threshold, positive, and negative predictive value were calculated.
Results: The results showed that in 6 patients with Gleason score 6, the mean value of ADC using 32 ROIs (Region of Interests) was 0.982 ± 0.909 SD s/mm2. In 9 patients with Gleason score 7, the mean ADC value using 52 ROIs was 0.961 ± 0.806 SD s/mm2. In 6 patients with Gleason score 8, the mean ADC value using 52 ROIs was 0.924 ± 0.786 SD s/mm2. In 4 patients with Gleason score 9, the mean ADC value using 24 ROIs was 0.812 ± 0.726 SD s/mm2. Pearson correlation analysis showed a significant negative correlation between Gleason score and ADC measurements (r = -0.926, P = 0.01).
Conclusion: According to the guidelines of the European association of urology in 2013, the main tools for diagnosing prostate cancer include DRE (Digital Rectal Examination), PSA (Prostate Specific Antigen) and TRUS (Trans-Rectal Ultrasonography)-guided biopsy. Prostate cancer is often multifocal. It is generally accepted that GS determines the prognosis, the lesion with the highest GS has the weakest prognosis. The correlation of imaging with histopathology is very important for the validation and creation of new imaging biomarkers. In particular, accurate correlation allows to analyze relationships between quantitative MRI-based parameters and histopathology, and allows to evaluate the accuracy of imaging in tumor examination. The main limitation of previous studies was the unreliability of the amount of GS obtained from biopsy and problems in determining the exact location of the tumor on MRI. To overcome this limitation, prostatectomy specimens were used for the image and GS communication in this study. The results showed that there was a significant negative relationship between ADC values calculated from DW images and GS of prostate cancer obtained from a prostatectomy sample.
Send email to the article author
| Rights and permissions | |
 |
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
