Discrimination between Intact and Decayed Pulp Regions in Carious Teeth by ADC Mapping

To examine possible differences between the evolution of cerebral watershed infarction (WI) and that of territorial thromboembolic infarction (TI) by using diffusion-weighted (DW) and T2-weighted magnetic resonance (MR) images and apparent diffusion coefficient (ADC) maps. Fourteen patients with TI and nine with WI underwent MR imaging from the acute to chronic infarction stages. ADC maps were derived from DW images. Lesion-to-normal tissue signal intensity ratios on ADC maps (rADC), echo-planar T2-weighted images, and DW images were calculated. Lesion volumes at acute or early subacute infarction stages were measured on DW images, and final lesion volumes were estimated on fluid-attenuated inversion-recovery images. Analysis of variance revealed a significant difference in temporal evolution patterns of rADC between WI and TI (P <.001). rADC pseudonormalization following TI began about 10 days after symptom onset, but that following WI did not occur until about 1 month after symptom onset. The Pearson correlation coefficient between final and initial infarct volumes was 0.9899 for both infarction subtypes, indicating that the initial ischemic injury volume measured at the acute or early subacute stage predicted the final lesion volume fairly well. The evolution time of ADC is faster for TI than for WI. This difference, which likely originates from the different pathophysiologic and hemodynamic features of the two infarction types, might account for the relatively large range of ADC values reported for the time course of ischemic strokes.

To investigate and determine the optimal b-values for Diffusion Weighted Imaging(DWI) for Apparent Diffusion Coefficient(ADC) maps in differentiating normal, benign and malignant breast tissue. Twenty-five patients underwent diffusion-weighted magnetic resonance imaging (DWI-MRI) and conventional breast MRI with suspicious breast fmdings(BIRADS >4). Breast lesions were defined by pathology. The DWI was acquired with different b-values ranging from 0,500, 600,750 and 1000s/mm2 . Apparent Diffusion Coefficient(ADC) maps of breast tissue were constructed using different b-values, e.g., using either 2 b-values(0- 1000) or combinations of 3 or more (0,500,1000 or 0,600,750,1000). Quantitative analyses of the ADC maps of glandular, fatty and lesion tissue were obtained. Ratios of lesion to glandular tissue(L/GT) and signal to noise(SNR) were assessed. Paired t-tests were performed for statistical significance. Eighteen patients had invasive ductal carcinoma and 7 had benign breast lesions. The mean ADC value for malignant lesions using all b values was 1.17±0.16×10-3mm2 /s with a lesion to glandular(L/GT) ratio=0.65. The benign lesions, ADC map value was 1.86±0.03×10-3mm2 /s with L/GT=0.98. There was a significant difference(P<0.05) between benign and malignant lesions ADC map value.The lowest SNR(12±6) was with single b-values. There was a significant difference(P<0.05) in SNR with multiple b-values(34±6) compared to single b-values. The highest SNR was given by using two b values greater than 500. Finally, the background noise for all combinations was surprising stable and ranged between 60±20%. This is the first study to investigate the effect of changing different b values in DWI breast imaging. There were significant differences in the SNR between single and multiple b values. Our data show suggest that the recommended b-values for DWI in breast are 0, and two that are 500 or greater. Therefore use of at least 3 b-values in DWI/ADC mapping of breast lesions are needed for better characterization of benign and malignant breast tissue. P50CA88843, Avon Foundation for Women:01-2008-012, U01CA070095, andU01CA140204.

The correct staging of rectal cancer is very important for treatment. This study aims to show the contribution of diffusion-weighted imaging (DWI) to staging, to predict tumor differentiation and neoadjuvant chemoradiotherapy response using DWI. The study con- sisted of 36 patients and 22 control groups. 12 patients who received neoadjuvant therapy were evaluated before and after treatment. Magnetic Resonance Imaging (MRI) and DWI were performed to all patients and apparent diffusion coefficient (ADC) maps were obtained. The findings were compared with histopathological results. T staging accuracy was 72.2% on MRI. N staging accuracy rate was 75% on the T2 sequence and 72.2% on DWI. Tumoral rectal ADC values were significantly decreased compared to the normal rectal wall (p&lt; 0.001). Mean T3 and T4 (extramural) ADC values were significantly decreased compared to the T2 stage (intramural) ADC values (p&lt; 0.001). ADC and relative ADC (lymph node / primary tumor ADC) values of the metastatic lymph nodes were signifi- cantly decreased compared to benign lymph nodes (p&lt; 0.001). According to the ADC cut point, N staging accuracy was found to be 83%. The ADC values of the low differentiated group were significantly decreased compared to the moderately and well-differentiated group (p&lt; 0.011). In the control MRI of patients receiving neoadjuvant therapy, the ADC increase in the group that responded well to the treatment was significantly higher than the group with partial response (p &lt;0.004). As a result, DWI and ADC are useful for preoperative rectum cancer evaluation. Keywords: Rectum cancer, Staging, Diffusion MRI

Pulpal blood supply can be measured noninvasively and objectively via laser-Doppler fluxmetry. The aim of the study was to measure and compare pulpal laser-Doppler (LD) flux values for permanent non-carious teeth and carious teeth with different degrees of caries progression. Conventional sensitivity tests were also conducted for a comparative analysis to clarify the difference between tooth sensitivity and vitality. Carious lesions were detected and assessed in 15 adult subjects using the International Caries Detection and Assessment System (ICDAS) criteria. Pulpal sensitivity of selected carious teeth (without previous prosthetic restoration or endodontic treatment) and suitable caries-free teeth were then tested with a cold stimulus and subsequently with a weak electric current, whereas their pulpal LD flux was recorded at a separate visit using individually designed silicone probe holders. The LD flux values for teeth with an ICDAS score 6 were significantly lower compared to the values for teeth with an ICDAS score 1 (p < 0.05). Pulpal LD flux values of teeth with active caries were significantly lower than those of teeth with solely inactive carious lesions (p < 0.05). The degree of agreement between sensitivity and vitality testing was fair within both of the pairs: cold test/LDF (κk = 0.232, p = 0.00) and electric test/LDF (κk = 0.354, p = 0.00). Pulpal LD flux measurement proved to be reliable in the pulp vitality assessment of carious and non-carious teeth and might improve the reliability of clinical decisions when used in addition to standard clinical diagnostic protocols.

We aimed to identify the radiologic features of uterine cervical adenocarcinoma associated with lobular endocervical glandular hyperplasia (LEGH). We retrospectively analyzed magnetic resonance (MR) images and pathologic findings of eight patients who underwent preoperative MR imaging followed by surgical resection and who were pathologically diagnosed with adenocarcinoma (except for adenocarcinoma in situ) associated with LEGH. We assessed the following MR findings: multicystic component (MC), solid component (SC), signal intensity of SC on diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) map, and radiological stage (r-stage) based on the FIGO classification. A pathologist reevaluated the pathological stage (p-stage) according to the FIGO classification. We correlated the MR findings with the pathologic features. Eight patients were classified into the following three types based on the MR findings: type A, MC and SC; type B, only SC; and type C, only MC. In the five patients with type A, diffusion restriction (DR) was seen on DWI and the ADC map. In 80% of type A cases, the r-stage matched the p-stage. In the one patient with type B, DR was not seen on DWI or the ADC map, and the r-stage matched the p-stage. In the remaining type C cases, DR was not seen on DWI or the ADC map, and the r-stage was underestimated compared with the p-stage. On MR imaging, the most common type of adenocarcinoma with LEGH is type A; type C is difficult to diagnose as carcinoma.

Apparent diffusion coefficient (ADC) thresholds for tissue infarction have been identified in acute stroke. IV tissue plasminogen activator (tPA) is associated with tissue salvage. We hypothesized that tPA would lower the ADC threshold for infarction. ADC and mean transit time (MTT) maps were generated for 26 patients imaged within 6 hours of stroke onset (12 tPA and 14 conservatively managed controls). MTT maps and day-90 T2-weighted images were coregistered to ADC maps. Relative ADC (rADC) values were calculated for initial diffusion-weighted imaging (DWI) lesions, infarct growth regions (final infarct volume-the acute DWI lesion volume), and hypoperfused salvaged regions (HS; MTT map abnormality-the final infarct volume). When relevant, the DWI lesion was subdivided into DWI reversal and DWI infarct regions. Mean DWI lesion rADC was 0.79 in tPA and 0.74 in untreated patients (P=0.097). Mean rADC in HS and infarct growth regions were similar in tPA patients (0.950 and 0.946) and untreated patients (0.957, P=0.76; 0.970, P=0.08, respectively). The rADC in HS tissue was directly correlated with the time to treatment with tPA (r=0.685; P=0.029). DWI reversal was seen in 67% of tPA-treated patients and in 36% of those conservatively managed (Fisher exact test; P=0.238). In the 13 patients with DWI reversal, the mean rADC in these regions (0.81+/-0.07) was significantly higher than in the acute DWI region that infarcted (0.74+/-0.07; P=0.02), although no absolute thresholds could be identified. The peri-DWI lesion region contains tissue with intermediate ADC values. The fate of this tissue is variable and cannot be predicted based on the ADC alone. DWI expansion occurs in bioenergetically normal tissue, and this is attenuated by tPA in a time-dependent fashion.

A retrospective evaluation of diffusion-weighted imaging, apparent diffusion coefficient (ADC) maps, and T2-weighted images in patients with cervical compression myelopathy. To correlate high signal intensity on ADC maps and T2-weighted images to neurologic severity and radiologic spinal cord compression. Previous studies indicated that the ADC map was more sensitive in detection of cervical compressive myelopathy than T2-weighted imaging. The relationship to neurologic severity has not been previously published. In 100 patients with or without cervical compressive myelopathy, the magnetic resonance appearance of the spinal cord on ADC maps and T2-weighted images was evaluated independently by 2 readers. On the basis of the presence or absence of abnormality, patients were categorized into 4 groups by type of intramedullary change. The degree of canal compression and the Japanese Orthopedic Association (JOA) score for cervical myelopathy were compared among the 4 types. The type I group consisted of 32 patients without signal change on either ADC maps or T2-weighted images. The type II group had 33 patients with high signal intensity only on the ADC map. The type III group contained 28 patients with high signal intensity on both the ADC map and the T2-weighted images. The type IV group comprised 7 patients with high signal intensity only on T2-weighted images. The degree of canal compression and the JOA scores were significantly different among the 4 groups (P < 0.005). Most type III (25 of 28) and type IV (7 of 7) patients had severe cord compression. Average JOA scores in each type were (I) 16.0, (II) 14.7, (III) 11.7, and (IV) 8.7. ADC maps demonstrated internal changes in the early stages of chronic spinal cord compression, but had limitations for the detection of intramedullary changes in late-stage myelopathy.

Objectives: This study aimed to assess intra- and inter-examiner reliability of International Caries Detection and Assessment System (ICDAS) and modified epidemiology ICDAS (MOD) code by undergraduate dental students with different clinical experiences. Methods: A total of 150 dental undergraduate students with varying clinical experiences (0, 1 and 2 years of clinical experience) were recruited. Participants received training through a theoretical lecture on ICDAS criteria by an experienced National Benchmark Group (NBG) examiner and underwent e-learning program prior to ICDAS calibration. Visual examination on extracted permanent teeth (N= 45) with different location and stages of caries progression ranging from ICDAS scores 0 to 6, was performed using the ICDAS criteria. The assessments were repeated after one hour. The data were analysed to evaluate inter-examiner and intra-examiner reliability in the form of kappa scores using SPSS 23 Software. Results: Mean kappa values for intra- and inter-examiner reliability for ICDAS code, were between 0.41 to 0.60, and 0.61 to 0.80 respectively. For MOD code, mean kappa values for intra- and inter-examiner reliability were between 0.61 to 0.80. Good intra-examiner agreement (&gt;0.61) was observed in both ICDAS and MOD code for all groups. Conclusion: All students performed similar agreement, therefore, clinical experience within 2 years does not influence the performance of visual inspection in detecting caries using ICDAS. The results of the study shows that ICDAS and modified epidemiology ICDAS codes has good reproducibility and is feasible to be used as a tool in clinical practice as well as patient education.

In cervical carcinoma, lymph node involvement is a key indicator of disease progression and a critical prognostic factor that influences staging and treatment. Accurate identification of metastatic lymph nodes is essential for optimal management. Diffusion-weighted MRI combined with apparent diffusion coefficient (ADC) mapping provides a non-invasive approach for evaluating tissue cellularity and may enhance the identification of metastatic lymph nodes, surpassing traditional size-based criteria. The purpose of the study is to assess the effectiveness of diffusion-weighted imaging (DWI) and ADC values in differentiating between metastatic and non-metastatic lymph nodes in patients with cervical cancer. The study focuses on imaging findings without histopathological confirmation, aiming to determine whether ADC measurements can reliably indicate nodal metastasis. Thirty patients with histologically confirmed cervical cancer (International Federation of Gynecology and Obstetrics (FIGO) stage IB to IIIC) were prospectively enrolled in a study with a duration of three months. All patients underwent pre-treatment pelvic MRI including DWI on a 1.5 T scanner (b-values: 50, 400, and 800 s/mm²). ADC maps were obtained, and the ADC values of lymph nodes were quantitatively analyzed. Lymph nodes were categorized as suspicious for metastasis based on MRI features, including a short-axis diameter of ≥10 mm, round shape, or the presence of necrosis. Nodes lacking these characteristics were considered benign. Histopathological confirmation of lymph nodes was not conducted. A sample size of 30 was calculated via Fisher's z-test formula for correlation (assuming r = 0.685, 99% confidence, 90% power). Of 30 patients (mean age -63.5 years, range 51-80), one-third had radiologic evidence of lymph node involvement on MRI (stage IIIC1 by the FIGO 2018 criteria), while the remainder had no enlarged nodes. DWI showed qualitatively restricted diffusion in nodes suspected of metastasis. Quantitatively, ADC values were markedly lower in suspicious (metastatic-appearing) nodes compared to non-suspicious nodes. The mean ADC of nodes deemed metastatic was approximately 0.90 × 10-3mm²/s, versus ~1.30 × 10-3mm²/s for benign nodes (p < 0.001). Notably, all nodes with ADC < 1.0 × 10-3mm²/s were in the metastatic-suspect group, whereas nodes with ADC > 1.0 × 10-3mm²/s were benign, suggesting a clear separation. Using an ADC threshold of ~1.0 × 10-3mm²/s to define positive nodes, the sensitivity for detecting metastatic nodes was ~93% and specificity ~100% in this cohort. DWI and ADC mapping demonstrated strong potential in differentiating metastatic from non-metastatic lymph nodes in cervical carcinoma patients. Metastatic nodes showed significantly lower ADC values (around or below 1.0 × 10-3mm²/s) compared to non-metastatic nodes. These findings indicate that ADC measurements can augment conventional MRI assessment of lymph nodes, providing a non-invasive indicator of nodal metastasis. This could be especially valuable when surgical nodal sampling is not performed.

This study aims for targeted biopsy validation of magnetic resonance fingerprinting (MRF) and diffusion mapping for characterizing peripheral zone (PZ) prostate cancer and noncancers. One hundred four PZ lesions in 85 patients who underwent magnetic resonance imaging were retrospectively analyzed with apparent diffusion coefficient (ADC) mapping, MRF, and targeted biopsy (cognitive or in-gantry). A radiologist blinded to pathology drew regions of interest on targeted lesions and visually normal peripheral zone on MRF and ADC maps. Mean T1, T2, and ADC were analyzed using linear mixed models. Generalized estimating equations logistic regression analyses were used to evaluate T1 and T2 relaxometry combined with ADC in differentiating pathologic groups. Targeted biopsy revealed 63 cancers (low-grade cancer/Gleason score 6 = 10, clinically significant cancer/Gleason score ≥7 = 53), 15 prostatitis, and 26 negative biopsies. Prostate cancer T1, T2, and ADC (mean ± SD, 1660 ± 270 milliseconds, 56 ± 20 milliseconds, 0.70 × 10 ± 0.24 × 10 mm/s) were significantly lower than prostatitis (mean ± SD, 1730 ± 350 milliseconds, 77 ± 36 milliseconds, 1.00 × 10 ± 0.30 × 10 mm/s) and negative biopsies (mean ± SD, 1810 ± 250 milliseconds, 71 ± 37 milliseconds, 1.00 × 10 ± 0.33 × 10 mm/s). For cancer versus prostatitis, ADC was sensitive and T2 specific with comparable area under curve (AUC; (AUCT2 = 0.71, AUCADC = 0.79, difference between AUCs not significant P = 0.37). T1 + ADC (AUCT1 + ADC = 0.83) provided the best separation between cancer and negative biopsies. Low-grade cancer T2 and ADC (mean ± SD, 75 ± 29 milliseconds, 0.96 × 10 ± 0.34 × 10 mm/s) were significantly higher than clinically significant cancers (mean ± SD, 52 ± 16 milliseconds, 0.65 ± 0.18 × 10 mm/s), and T2 + ADC (AUCT2 + ADC = 0.91) provided the best separation. T1 and T2 relaxometry combined with ADC mapping may be useful for quantitative characterization of prostate cancer grades and differentiating cancer from noncancers for PZ lesions seen on T2-weighted images.

To examine the clinicopathological features and identify the predictors of pathological upgrading in low-risk prostate cancer (PCa) patients without hypointense lesions on the apparent diffusion coefficient (ADC) map calculated from multiparametric magnetic resonance imaging. We reviewed the medical records of 1905 PCa patients who underwent radical prostatectomy between 2007 and 2015. All ADC images were graded using the five-grade Likert scale; the positive hypointense lesions were graded 4-5. We analyzed 256 patients with low-risk classifications according to D'Amico criteria. Patients were classified into two groups according to the pathologic upgrading in the surgical specimens. The predictive factors for pathologic upgrading were evaluated using amultivariate logistic regression analysis. In 256 patients with low-risk PCa, the percentage of positive cores [odds ratio (OR) 1.09; 95% confidence interval (CI) 1.02-1.16], the percentage of cancer in the positive cores (OR 1.07, 95% CI 1.03-1.12), and the presence of hypointensity on an ADC map (OR 2.28; 95% CI 1.23-4.22) were independent predictors of pathologic upgrading. Notably, 138 of low-risk patients (53.9%) had no hypointense lesions on an ADC map. Of these 138 patients, the percentage of positive cores (OR 1.09; 95% CI 1.01-1.18) and the percentage of cancer in the positive cores (OR 1.06; 95% CI 1.01-1.12) remained independent predictors of pathologic upgrading. In low-risk PCa patients without hypointense lesions on an ADC map, biopsy-related parameters such as the percentage of positive cores and the percentage of cancer in the positive cores were independent predictors of pathological upgrading following radical prostatectomy.

Purpose To compare single-shot echo-planar diffusion-weighted imaging-derived apparent diffusion coefficient (ADC) maps with fat-saturated (FS) proton density (PD)-weighted turbo spin-echo (TSE) imaging in the detection of bone marrow lesions (BMLs) after knee trauma. Materials and Methods Institutional review board approval was obtained from Leipzig University. Written informed consent was waived. Three radiologists retrospectively re-examined 97 consecutive patients with reported knee trauma who underwent 1.5-T magnetic resonance (MR) imaging within 90 days of knee trauma. The following sequences were used: (a) sagittal T1-weighted TSE and FS PD-weighted TSE and (b) sagittal T1-weighted TSE and single-shot echo-planar diffusion-weighted imaging-derived ADC mapping. BMLs on the lateral and medial femoral condyle, lateral and medial aspect of the tibial plateau, and patella were documented. Volumetry was performed on BMLs with a thickness of at least 15 mm (major BMLs). ADC values were measured in intact bone marrow and major BMLs. A McNemar test and t tests were used as appropriate to test for significant differences between BML number and volume at an α level of .05. Results Significantly more patients showed at least one BML on ADC maps (98%, 95 of 97 patients) than on FS PD-weighted TSE images (86%, 84 of 97 patients) (P < .001). Of the affected regions detected on FS PD-weighted TSE images, 97% (170 of 175 regions) were identified consistently on ADC maps. Only 58% of the affected regions detected on ADC maps (170 of 293 regions) were identified on FS PD-weighted TSE images (P < .001). Median volume of concordant major BML was approximately two times larger on ADC maps (81 cm3) than on FS PD-weighted TSE images (39 cm3) (P < .001). The ADC values of intact bone marrow and BMLs did not overlap. Conclusion ADC maps are more sensitive than corresponding FS PD-weighted TSE images for detection of BML after knee trauma and allow detection of significantly more and larger BMLs. ADC map evaluation improves diagnostic performance in regions with insufficient spectral fat saturation, such as the patella. © RSNA, 2016 Online supplemental material is available for this article.

Objective: The consistency of pituitary macroadenomas can be a confounding factor during transnasal transsphenoidal decompression, often necessitating incomplete removal and need for a transcranial approach for complete tumor excision. Very few studies have evaluated preoperative tumor consistency in relation to imaging findings. Our objective was to determine whether conventional magnetic resonance images and diffusion-weighted (DW) imaging with apparent diffusion coefficient (ADC) maps are predictive of the consistency of pituitary macroadenomas. Methods: A retrospective study of 31 patients who had undergone surgery for pituitary macroadenoma in our hospital. Preoperative magnetic resonance images were reviewed and regions of interest were drawn on the macroadenoma and normal white matter on DW images independently by 2 neuroradiologists. Consistency of macroadenomas was determined from the surgical records and was classified into soft, intermediate, or hard. Mean ADC values, signal intensity ratio of tumor to white matter within regions of interest on conventional and DW images, and degree of enhancement were compared with tumor consistency using analysis of variance. Results: The mean ADC values in the soft group was 0.754×10−3 mm2/s, in the intermediate group was 0.963×10−3 mm2/s, and in the hard group was 1.312×10−3 mm/s. Statistical analysis revealed a significant correlation between consistency and ADC values (P<0.004). There was no significant association between tumor consistency and signal intensity or degree of contrast enhancement. Conclusions: The findings in this study suggest that DW images with ADC maps are useful for preoperative prediction of consistency of pituitary macroadenomas.

Early detection of disc degeneration and categorizing them is very important for the treatment plan and better prognosis. We aimed to assess the efficacy of apparent diffusion coefficient (ADC) mapping and T2 mapping in the early detection and grading of the severity of degenerative disc disease. In this review, the articles published until July 2022, from the PubMed database were used. All articles contained information about the application of ADC and T2 mapping in the detection of disc degeneration. A total of 40 articles were included in this review. We assessed each article for the feasibility of both techniques to categorize the degeneration. ADC values of nucleus pulposus (NP) showed a negative correlation with Pfirrmann grades and age. T2 values of NP and annulus fibrosus (AF) are significantly decreased with an increase in Pfirrmann grades. And also, as age increases, T2 values of NP and posterior AF decreased significantly. ADC and T2 mapping techniques are sensitive in the detection and categorization of disc degeneration. It is highly recommended to include quantitative magnetic resonance imaging techniques in routine spine imaging protocol in a patient with complaints of back pain.

Prostate cancer (PCa) is a highly heterogeneous disease, making tailored treatment approaches challenging. Magnetic resonance imaging (MRI), notably diffusion-weighted imaging (DWI) and the derived Apparent Diffusion Coefficient (ADC) maps, plays a crucial role in PCa characterization. In this context, radiomics is a very promising approach able to disclose insights from MRI data. However, the sensitivity of radiomic features to MRI settings, encompassing DWI protocols and multicenter variations, requires the development of robust and generalizable models. To develop a comprehensive radiomics framework for noninvasive PCa characterization using ADC maps, focusing on identifying reliable imaging biomarkers against intra- and inter-institution variations. Two patient cohorts, including an internal cohort (118 PCa patients) used for both training (75%) and hold-out testing (25%), and an external cohort (50 PCa patients) for independent testing, were employed in the study. DWI images were acquired with three different DWI protocols on two different MRI scanners: two DWI protocols acquired on a 1.5-T scanner for the internal cohort, and one DWI protocol acquired on a 3-T scanner for the external cohort. One hundred and seven radiomics features (i.e., shape, first order, texture) were extracted from ADC maps of the whole prostate gland. To address variations in DWI protocols and multicenter variability, a dedicated pipeline, including two-way ANOVA, sequential-feature-selection (SFS), and ComBat features harmonization was implemented. Mann-Whitney U-tests (α=0.05) were performed to find statistically significant features dividing patients with different tumor characteristics in terms of Gleason score (GS) and T-stage. Support-Vector-Machine models were then developed to predict GS and T-stage, and the performance was assessed through the area under the curve (AUC) of receiver-operating-characteristic curves. Downstream of ANOVA, two subsets of 38 and 41 features stable against DWI protocol were identified for GS and T-stage, respectively. Among these, SFS revealed the most predictive features, yielding an AUC of 0.75 (GS) and 0.70 (T-stage) in the hold-out test. Employing ComBat harmonization improved the external-test performance of the GS model, raising AUC from 0.72 to 0.78. By incorporating stable features with a harmonization procedure and validating the model on an external dataset, model robustness, and generalizability were assessed, highlighting the potential of ADC and radiomics for PCa characterization.