RPS 2102 - How to optimise and use breast MRI

Author Block: S. V. Grinsven¹, R. Mann², K. M. Duvivier³, M. De Jong⁴, P. K. De Koekkoek-Doll³, C. Loo³, J. Veltman⁵, W. B. Veldhuis¹, F. T. D. T. S. G. -¹; ¹Utrecht/NL, ²Nijmegen/NL, ³Amsterdam/NL, ⁴Den Bosch/NL, ⁵Almelo/NL
Purpose: Costs and time of a full multi-parametric MRI protocol may be reduced by using an abbreviated MRI (AB-MRI) protocol. The DENSE trial’s multiparametric protocol provided the unique opportunity to study the accuracy of various AB-MRI protocols, to identify the minimal protocol necessary to maintain high diagnostic accuracy.
Methods or Background: Seven radiologists performed incremental reads of a subset of 518 MRI examinations from the DENSE trial (women with extremely dense breasts and negative mammography). Different sequences were added in four incremental steps, starting with: 1) both high resolution (hi-res) and ultra-fast T1-weighted images (T1WI), up to 120 seconds after contrast-injection only, 2) complemented by diffusion-weighted images (DWI), 3) T2-weighted images (T2WI), and 4) finally adding all remaining full protocol sequences: non-fatsat-T1-weighted pre-contrast images, all remaining dynamic phases, and curve-kinetics. Each radiologist assessed the same MRI examinations and provided BI-RADS scores for all four steps. We calculated the pooled sensitivity and specificity per incremental step by using a generalized estimating equation model, and the pooled reading time per incremental step by using a linear mixed model.
Results or Findings: The sensitivity and specificity of the most abbreviated MRI protocol (step 1) were not significantly different from that of the full multiparametric MRI protocol (step 4) (p=0.68, p=0.39). The pooled reading time of step 1 was almost 50% shorter than that of the full multiparametric MRI protocol (p<0.01), and the MR acquisition time was 70-80% shorter, depending on the hospital and scanner vendor.
Conclusion: In a screening setting, a full multiparametric MRI protocol, including pre-contrast DWI and T2WI, and delayed post-contrast T1WI, did not provide significant additional diagnostic information for making a recall/no-recall decision compared to an ultrafast bi-dynamic T1WI-only protocol.
Limitations: A prospective screening study should confirm these results.
Funding for this study: The DENSE trial is financially supported by the University Medical Center Utrecht (UMC Utrecht, Project number: UMCU DENSE), the Netherlands Organization for Health Research and Development (ZonMw, Project numbers: ZONMW-200320002-UMCU and ZonMW Preventie 50-53125-98-014), the Dutch Cancer Society (KWF Kankerbestrijding, Project numbers: DCS-UU-2009-4348, UU-2014-6859 and UU-2014-7151), the Dutch Pink Ribbon / a Sister’s hope (Project number: Pink Ribbon-10074), Bayer AG Pharmaceuticals, Radiology (Project number: BSP-DENSE), and Stichting Kankerpreventie Midden-West. For research purposes, Volpara Health Technologies (Wellington, New Zealand) has provided Volpara Imaging Software 1.5 for installation on servers in the screening units of the Dutch screening program.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: On November 11, 2011, the trial was approved by the Dutch Minister of Health, Welfare, and Sport, under advisement from the Health Council of the Netherlands.

Author Block: J. T. Lee¹, B. K. Seo¹, M. S. Bae¹, H. Choi², K. R. Cho², O. Woo², S. E. Song², S-Y. Kim², S. Cheon¹; ¹Ansan/KR, ²Seoul/KR
Purpose: Environmental sustainability in healthcare is crucial, and MRI is a major energy-intensive device in radiology. We aimed to identify optimal energy-saving breast MRI protocols by comparing energy consumption and carbon emissions of abbreviated MRI, ultrafast dynamic contrast-enhanced MRI (Ultrafast-DCE), and artificial intelligence (AI)-assisted protocols against multiparametric MRI, conventional dynamic contrast-enhanced MRI (Conventional-DCE), and non-AI-assisted protocols using patient and phantom tests.
Methods or Background: A 3-T MRI scanner equipped with a dedicated breast coil and a power meter providing a 1-Hz sampling rate was used. We compared scan time (seconds), total energy (kW), energy consumption (kWh), and carbon emissions per scan (kgCO2e) between abbreviated (n=74) and multiparametric (n=81) protocols, Ultrafast-DCE (n=81) and Conventional-DCE (n=81), and AI-assisted (n=76) and non-AI-assisted (n=76) protocols in 307 patients. Additionally, the signal-to-noise ratio was compared between AI-assisted and non-AI-assisted protocols using a breast MRI phantom. The abbreviated protocol included T2-weighted imaging (T2), diffusion-weighted imaging (DWI) (b values: 0 and 800 s/mm²), four-phase DCE T1-weighted imaging (T1), and axillary T1. The multiparametric protocol consisted of T2, DWI (b values: 0, 800, and 1400 s/mm²), Ultrafast-DCE, five-phase DCE T1, and axillary T1.
Results or Findings: Abbreviated MRI reduced scan time by 40%, total energy by 36%, and energy/carbon emissions by 62% compared to multiparametric MRI. Ultrafast-DCE reduced scan time by 81%, total energy by 83%, and energy/carbon emissions by 97% compared to Conventional-DCE. AI-assisted MRI reduced scan time by 29%, total energy by 30%, and energy/carbon emissions by 52% compared to non-AI-assisted MRI, while increasing signal-to-noise ratio by 16% (all p < 0.001).
Conclusion: Abbreviated, ultrafast, and AI-assisted MRI protocols significantly reduce energy consumption and carbon emissions, supporting eco-friendly MRI practices.
Limitations: Not applicable.
Funding for this study: National Research Foundation of Korea funded by the Korea government (RS-2024-00347290).
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: No

Author Block: C. C. Arıkan, M. A. Arıkan, M. A. Nazli; Istanbul/TR
Purpose: Diffusion-weighted imaging(DWI) presents a rapid, cost-effective, and non-contrast alternative to contrast-enhanced MRI(CE-MRI).This study aims to evaluate the diagnostic performance of DWI compared to CE-MRI in breast cancer screening for high-risk women under 40 while assessing inter-rater agreement and correlating findings with biopsy outcomes and ultrasound BI-RADS categories.
Methods or Background: We retrospectively analyzed the DWI and CE-MR images of 112 women under the age of 40 who had breast MRI screening due to high risk. Two radiologists independently reviewed the images without knowledge of ultrasound or pathological results. Patients were classified as having "diffusion restriction present or absent" and "pathological contrast enhancement present or absent." Inter-rater agreement was assessed using Cohen’s kappa coefficient.MRI findings were compared to ultrasound-based BI-RADS reports and biopsy results to determine sensitivity and specificity.
Results or Findings: Lesion detection inter-rater agreement was high for DWI(kappa=0.83), and moderate for CE-MRI(kappa=0.57). Of the 112 patients, 43 underwent biopsy, with 37 benign and 6 malignant diagnoses. DWI detected 5 out of 6 malignant lesions (sensitivity 83.3%).DWI exhibited 10 false positives (specificity 73%).CE-MRI detected all malignant lesions (sensitivity 100%), but showed 30 false positives (specificity 18.9%). Among the 79 patients classified by BI-RADS with no biopsy, 57 were BI-RADS1-2, with 5(%8.7) false positives on DWI and 14(%24,5) on CE-MRI. Of the remaining 12 BI-RADS3 cases were recommended for follow-up, DWI was positive in 2(%16.6) and CE-MRI in 7(%58.3).
Conclusion: DWI shows high sensitivity and specificity, particularly in breast cancer screening for women at high risk below 40 years.The high inter-rater agreement shows its reliability, and the reduced recall rate suggests that DWI has the potential to reduce unnecessary treatments compared to CE-MRI.
Limitations: The study is limited by loss to follow-up patients and those with incomplete diagnostic tests
Funding for this study: No funding was provided for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Başakşehir Çam and Sakura City Hospital Ethics Committee

Author Block: L. Nohava, R. Czerny, M. Tik, E. Laistler, R. Frass-Kriegl; Vienna/AT
Purpose: Supine positioning during breast MRI using a wearable coil at 3 T has the potential to improve patient comfort and to extend the inclusion criteria for breast MR examinations (obesity, pregnancy). While the technical performance of the wearable coil for supine breast MRI is being assessed in ongoing studies, the aim of this study was the evaluation of patient perception with the goal of ensuring comfortable patient-oriented breast MR examinations.
Methods or Background: A questionnaire evaluating the impact of radiofrequency coils on patient comfort in MRI as an add-on to clinical studies comparing the performance of flexible coils with standard rigid coils was developed. In an IRB-approved breast MRI study, patients underwent one exam in supine using a wearable flexible coil and one prone reference exam. After each exam, patients filled in the questionnaire with 18 items using a 7-point Likert scale. So far, 10 questionnaire sets were collected. The study population had a range of different bra sizes (70B-95D), ages (20-64 years), and BMIs (19-30 kg/m2).
Results or Findings: Significant improvement in patient comfort during supine breast MRI was found for the following items: “I felt comfortable before the exam.” (p<0.009); “I found it cumbersome or physically demanding to take the lying position.” (p<0.026); ”I felt comfortable during the exam.” (p<0.043); “I found the lying position comfortable.” (p<0.047).
9 patients commented on pain or discomfort in prone whereas only 1 patient commented on discomfort due to peripheral nerve stimulation in supine breast MRI.
Conclusion: Patients perceived supine BraCoil MRI as significantly more comfortable than prone MRI, in anticipation of and during the exam.
Limitations: The limitations of the study are the small sample size, and mono-center character.
Funding for this study: Funding was provided by by the Austrian Science Fund (FWF)/Agence Nationale de Recherche (ANR) grant FWF I-3618/ANR-17-CE19-0022 “BraCoil” and FWF grant P37189 “OPTIMAL”, the Horizon Europe Grants No. 101078393 “MRITwins” and No. 101071008 “CITRUS”, and the Austrian Society for Senology (ÖGS) support grant.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Ethics Committee of the Medical University of Vienna (EK No. 2137/2021).

Author Block: S. Marziali, L. Corradini, M. Zanardo, C. Depretto, G. Della Pepa, G. Irmici, G. P. Scaperrotta, F. Sardanelli; Milan/IT
Purpose: Breast MRI is an established technique for diagnosing breast cancer using a multiparametric protocol, including sequences before/after contrast administration. The diagnostic performance depends on image quality, limited by misregistration artefacts due to patient movement. We propose a standardized image quality score (BreastMRI-QUAL).
Methods or Background: Two independent readers with 3 years of experience assigned a 4-level score to each sequence of 50 consecutive 1.5-T examinations at a tertiary cancer centre, as follows: 0 = not diagnostic for any cause; 1 = relevant artefacts/malpositioning with conserved diagnostic value for the specific case; 2 = slight artefacts/malpositioning with conserved diagnostic value; 3 = excellent image quality with full diagnostic value. The score per sequence was summed as follows: (T2-weighted*1) + (DWI-b=0*0.5) + (ADCmaps*0.5) + (T1-weighted-precontrast*1) + (T1-weighted-postcontrast*2) + (T1-weighted-subtracted*3). To obtain a global score (GS) from 0 to 10, the sum was divided by 2.4, with scores below 6 considered as insufficient.
Results or Findings: The average GS between the two readers was 8.0 ± 1.0 (mean ± standard deviation), with 42 cases (84%%) receiving a score ≥ 7. Only 1 case (2%) was scored <6 by both readers. The difference between the GSs assigned by the readers was ≤ 1 for 32 cases (64%), >1 but ≤ 2 for 17 cases (34%), and > 2 for 1 case (2%). The Bland-Altman analysis showed a mean difference (bias) of 0.28, with the limits of agreement ranging from -1.82 to 2.38, indicating the level of agreement between readers. The average assessment time/examination was 3 min.
Conclusion: BreastMRI-QUAL is a reproducible quality score system. Breast MRI image quality at a tertiary cancer center was good-to-excellent in over 80% of cases. Multicenter-multivendor validation studies are needed.
Limitations: Monocentric study, limited sample size.
Funding for this study: No funding.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Use of anonymized datasets outside clinical workflow.

Author Block: N. Smeins, J. Rooij, Van, E. Heuts, J. B. Houwers, S. Tuinder, T. J. Nijnatten; Maastricht/NL
Purpose: After breast amputation, and especially skin sparing mastectomy, there can be residual fibroglandular tissue (RFGT). RFGT can influence the risk of breast cancer recurrence. However, women are not screened for RFGT after mastectomy. This study examines the frequency in which RFGT can be detected on breast MRI after mastectomy and DIEP flap reconstruction and the influence of RFGT on breast cancer recurrence risk.
Methods or Background: This retrospective, single-centre study included female patients who underwent mastectomy and DIEP flap reconstruction. Post-reconstruction breast MRI exams from 2007-2022 were reassessed by a breast radiologist to detect potential presence of RFGT. The presence of RFGT was rated according to a confidence scale (1-5), with a score of 1 indicating ‘definitely no breast tissue’ and 5 indicating ‘definitely breast tissue’. Locations suspected of RFGT rated with a score of 4 or more were considered RFGT. RFGT prevalence was correlated with disease recurrence.
Results or Findings: A total of 73 patients (85 breasts) were included. RFGT was found in 15 (20.5%) patients and 16 (18.8%) breasts. Ten (13.7%) local recurrences had occurred after a mean follow-up period of 164.3 months (range: 27.0-381.0 months). Presence of RFGT resulted in a relative risk of 2.58 (95% CI 0.83-7.98) for recurring disease. Most breast MRI exams were assessed with a score of 3 on the confidence scale (39.2%).
Conclusion: RFGT is frequently detected on breast MRI after mastectomy and DIEP flap breast reconstruction and might have an association with disease recurrence. Future studies should focus on the clinical consequences of visualization of RFGT on breast MRI and whether there is a role for breast MRI in post-mastectomy patients.
Limitations: No limitations were identified.
Funding for this study: N. Smeins received a salary from Kankeronderzoekfonds Limburg.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by METC azM/UM (reference number METC 2022-3122).

Author Block: T. Arazi Kleinman¹, J. Lvovski¹, D. Walchok¹, G. Michal², T. Sella³; ¹Beer Yakov/IL, ²Tel Aviv/IL, ³Jerusalem/IL
Purpose: Current guidelines regarding post bilateral mastectomy (BMx) follow-up indicate no need for imaging. Regardless many patients are referred for breast MRI, though this practice is not evidence based. The aim of this study to evaluate the role of MRI in detection of cancer in post BMx women.
Methods or Background: Retrospective analysis of surveillance breast MRI in women s/p BMx between the years 2017-2020, at a single institution. Data collected included demographic information, personal and family history of breast cancer, indication for mastectomy (prophylactic vs. therapeutic) and reconstruction type. Suspicious MRI findings underwent biopsy and were correlated with pathology. Malignancy or benignity were determined by either pathology or stability on imaging for at least 12 months. Descriptive statistics applied with p<0.05 considered significant.
Results or Findings: 229 asymptomatic women s/p BMx aged 29-76±8.7 years underwent 709 surveillance studies for a total of 1418 breasts examined. Reconstructions included 1324 (93.3%) silicone, 47 (3.3%) autologous flaps and 47 (3.3%) with no reconstruction. 158 (69%) women underwent risk-reducing prophylactic Mx (rr-Mx) on one side and therapeutic Mx (t-Mx) for cancer on the other, 45 (20%) underwent bilateral rr-Mx and 26 (11%) underwent bilateral t-Mx for bilateral breast cancer. Overall, 782/1418 breasts underwent rr-Mx and 184/1418 breasts t-Mx. Cancer was detected in six breasts, five post t-Mx and one post rr-Mx. Overall cancer detection rate (CDR) was 0.4 (6/1418), higher in post t-Mx (CDR= 0.78, 5/636) than post rr-Mx (CDR= 0.12, 1/782), p<0.05. No cancers were detected in women post rr-BMx.
Conclusion: Cancer risk in women undergoing bilateral rr-Mx is negligible and likely does not warrant MRI surveillance. In contrast, CDR in post t-Mx women was 0.78 on the side of prior cancer and surveillance MRI may be considered.
Limitations: Single-institution, retrospective
Funding for this study: No Funding for this study
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Retrospective study

Author Block: R. J. Weinfurtner, S. Falcon, D. Ataya, M. Abdalah, O. Stringfield, N. Raghunand, B. Czerniecki, H. Soliman, H. Han; Tampa, FL/US
Purpose: To determine if functional tumor volume (FTV) analysis of human epidermal growth factor 2 positive (HER2+) breast cancer on pre-treatment MRI can help predict pathologic complete response (pCR) in patients treated with dendritic cell vaccine (DC1) neoadjuvant immunotherapy (NAI) followed by neoadjuvant chemotherapy (NAC).
Methods or Background: Patients with HER2+ breast cancer in this pilot trial underwent pre-treatment MRI, followed by ultrasound-guided intratumoral and intranodal DC1 injections, and then NAC prior to post-treatment MRI and surgery. FTV was calculated on pre-treatment post-contrast T1-weighted MRI images using a percent enhancement threshold of 70% and signal enhancement ratio set to 0. The %FTV was calculated as %FTV = FTV / segmented tumor volume. These were correlated with pathologic response at surgery using unpaired t-tests where p<0.05 was considered significant. FTV analysis was also compared to post-NAI/NAC pre-surgical MRI reports for diagnostic test accuracy comparison.
Results or Findings: Nineteen patients aged 29-74 (average 54) were included in the study, and 11 (57%) achieved pCR. MRI complete response (mCR) was seen in 11/19 (57%). However, accuracy for mCR predicting pCR was only 38%. For %FTV, median was 71%, and patients achieving pCR had higher %FTV (78% vs 57%, respectively, p=0.007). As a diagnostic test, %FTV above median accurately predicted pCR in 79% (95% confidence interval of 54-94%) with sensitivity 75%, specificity 86%, PPV 90%, and NPV 67%.
Conclusion: In this pilot study of combination NAI/NAC treatment for HER2+ breast cancer, tumors with above median %FTV on pre-treatment MRI demonstrated more favorable response to treatment, achieving pCR in 78%. Given that post-treatment MRI evaluation demonstrated low accuracy in predicting pCR, pre-treatment FTV analysis may prove a more accurate predictor in future studies.
Limitations: This study was a pilot study with limited sample size.
Funding for this study: Internal institution grant
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Institutional Review Board (IRB)

Author Block: M. Vukojevic, M. M. Nadrljanski, I. B. Krušac, D. Dimitrijevic, L. J. Raspopović, A. Djajic, M. Mihajlović; Belgrade/RS
Purpose: To examine the performance of the Kaiser score in the diagnosis of nonmass breast lesions on MRI.
Methods or Background: There were 39 female patients with pathologically confirmed nonmass lesions on breast MRI retrospectively analyzed. For each patient, the Kaiser score was determined and the BI-RADS category assigned. All patients were examined with full diagnostic protocol (T2W-STIR, T2W-TSE, T1W-TSE, DWI-ADC, 3D-FLASH) on 1.5T and 3T. Specificity and sensitivity of the Kaiser score were computed and the correlation between the Kaiser score and the BI-RADS classification was determined.
Results or Findings: In the group of patients with nonmass lesions (N=39), there were 10 patients (n1) with benign lesions (25.64%) and 29 patients with malignant lesions (n2). The mean Kaiser score value in n1=3 and in n2=7. There was significant correlation between the Kaiser score and BI-RADS category: n1=0.92; n2=0.66; N=0.79. Sensitivity of the Kaiser score was 89.7% and specificity equaled 70.0%. ROC curve value reached 0.89.
Conclusion: Kaiser score represents a reproducible, sensitive and specific diagnostic tool for assessment of nonmass lesions on breast MRI and may contribute to the adequate BI-RADS categorization and appropriate further steps in diagnostic algorithm of the patients with nonmass lesions.
Limitations: A single center retrospective analysis with the limited number of patients.
Funding for this study: None
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: No decision was required for the retrospective analysis without the patient intervention.

Author Block: Y. Shen, C. You, Y. Gu; Shanghai/CN
Purpose: To investigate whether qualitative and quantitative MRI features can reflect HER2-low expression breast cancer.
Methods or Background: The benefit of novel antibody-drug conjugates in HER2-low expression breast cancer suggests that the conventional binary classification HER2 status is insufficient to meet the needs of clinical diagnosis and treatment.The pre-treatment breast MRI images of 232 patients with pathologically confirmed breast cancer were retrospectively analyzed. Clinicopathologic features and MRI features were recorded. The qualitative MRI features included BI-RADS descriptors in DCE-MRI, and intratumoral T2 hyperintensity and peritumoral edema in T2WI. The quantitative features were generated by multi-b-value DKI, including mean, median, 5th, 95th percentile, skewness, kurtosis and entropy of ADC, Dapp and Kapp histogram from the mono-b and multi-b value models.
Results or Findings: HER2 status was categorized into HER2-zero (n=60), HER2-low (n=91) and HER2-over expression (n=81). For MRI features, the proportion of intratumoral T2 hyperintensity was higher in HER2-low than in other groups (p=0.009, p=0.008). For the lesion type, the mass lesions were more common in HER2-zero group than in HER2-low group (p=0.038). For mass lesions, mass shape (p<0.001) and margin(p<0.001) were significantly different between HER2-low and other groups, and mass shape is the independent predictive factor (HER2-low vs. HER2-zero: p=0.010, HER2-low vs. HER2-over: p=0.012). The area under the ROC curve (AUC) of qualitative features to distinguish HER2-low and -zero was 0.763 (95% CI: 0.667-0.859). Quantitative features differed between HER2-low and -overexpression groups, especially in NME-related lesions. All combined variables (Combinedall) had the best performance in predicting HER2-low, with an AUC of 0.802 (95% CI: 0.701 - 0.903).
Conclusion: Qualitative and quantitative MRI features are valuable for noninvasively distinguishing HER2-low expression breast cancer, and have their advantages in mass and NME lesions, respectively.
Limitations: Single-center retrospective study with limited samples.
Funding for this study: Not applicable.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Fudan University, Shanghai Cancer Center

Author Block: M. M. Nadrljanski, I. B. Krušac, D. Dimitrijevic, L. J. Raspopović, A. Djajic, M. Mihajlović; Belgrade/RS
Purpose: To assess the difference in pre- and post-contrast assessment of apparent diffusion coefficient (ADC) in early tumor response to neoadjuvant chemotherapy (NACT) after the 2nd cycle.
Methods or Background: There were 43 patients (N=43) included in retrospective analysis of ADC (b50, b850) in assessment of early tumor response in responders (R, n1=19) and non-responders (NR, n2=24), defined pathologically . In all patients, diffusion-weighted imaging (EPI sequence) was performed before and after application of contrast medium (gadobutrol, 1 mmol/L; 0.1 mL/kg). All patients were examined on either 1.5T or 3T unit in same institution with full diagnostic protocol (T2W-STIR, T2W-TSE, T1W-TSE, DWI b50, b850, 3D-FLASH, DWI b50, b850).
Results or Findings: In R, mean pre-contrast ADC: 1.17+/-0.07 mm2/s x 10-3, significantly differs from pre-contrast ADC in NR: 0.98+/-0.09 mm2/s x 10-3; p<0.0001. In R, mean post-contrast ADC value: 1.09+/-0.08 mm2/s x 10-3, significantly differs from post-contrast ADC in NR: 0.91+/-0.09 mm2/s x 10-3; p<0.0001. Significant difference was obtained for R between mean value of ADC on pre- and post-contrast DWI: 1.17+/-0.07 mm2/s x 10-3 vs. 1.09+/-0.08 mm2/s x 10-3; p<0.001. Significant difference was obtained for NR between mean value of ADC on pre- and post-contrast DWI: 0.98+/-0.97 mm2/s x 10-3 vs. 0.91+/-0.09 mm2/s x 10-3; p<0.001.
Conclusion: DWI before and after the application of contrast media did not clinically influence the differentiation between R and NR, although ADC was generally lower after the application of contrast medium. Although significantly different, ADC values for R before and after the application of the contrast medium did not show clinical relevance and did not interfere with the interpretation of the findings. The same applied for the ADC values for NR.
Limitations: Small number of patients in a single center retrospective study.
Funding for this study: None,
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Institutional Review Board waived the need for decision for the collection and analysis of medical record information, with no participant interaction.