Research Presentation Session: Genitourinary
RPS 1707 - Advances in imaging techniques for the genitourinary tract
March 1, 08:00 - 09:00 CET
7 min
Synthesising and adapting multiple data sources to design environmentally sustainable and clinically effective imaging pathways for visible haematuria
Simon Lambracos, London / United Kingdom
Author Block: J. B. John1, K. O'Flynn2, S. Lambracos3, B. Abdelqader4, S. Nalagatla4, S. Khadouri5, T. W. R. Briggs3, W. K. Gray3, J. Mcgrath1; 1Exeter/UK, 2Salford/UK, 3London/UK, 4Glasgow/UK, 5Leeds/UK
Purpose: To design a risk-stratified imaging pathway that reduces greenhouse gas (GHG) emissions using diagnostic performance evidence for ultrasound and computerised tomography urogram (CTU) in detecting upper tract urothelial cancer (UTUC).
Methods or Background: An audit of 15 UK hospitals’ first-line imaging for visible haematuria (VH) and non-visible haematuria (NVH), and use of one-stop cystoscopy and imaging, was performed. Urology referral data from the IDENTIFY study (N = 10,896) were linked to national Hospital Episode Statistics data to estimate absolute numbers of patients receiving ultrasound or CTU first-line across England annually.
Results or Findings: Ultrasound was the first-line imaging choice for VH and NVH in 53% and 93% of hospitals respectively; other hospitals used CTU as first-line. One-stop assessment was performed in 44% of audited cases. An estimated 127,701 ultrasound and 77,880 CTU were performed across England annually, including an estimated 20% and 2% of additional CTU for patients with VH and NVH respectively receiving ultrasound first due to persistent VH.
Informed by these data, a risk-stratified imaging pathway for patients with haematuria was developed. The pathway comprised: one-stop clinic ultrasound first-line for all, additional CTU for high-risk cases (VH + age>65 + smoking history), patient-initiated follow up direct to CTU for persistent VH if not performed initially. We estimate that this pathway could results in 191,097 ultrasounds, 51,320 CTU and 73% of assessments completed with one-stop assessment, leading to an estimated 269 tonnes CO2e reduction in net greenhouse gas emissions across England for one year. Around 0.1% of patients would have UTUC missed with first-line ultrasound on this pathway.
Conclusion: Adoption of this evidence-based pathway will reduce GHG emissions whilst delivering greater risk-stratified imaging use, improving equity of healthcare access and reducing unwarranted use of CTU.
Limitations: N/A
Funding for this study: Not applicable
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Not applicable
Purpose: To design a risk-stratified imaging pathway that reduces greenhouse gas (GHG) emissions using diagnostic performance evidence for ultrasound and computerised tomography urogram (CTU) in detecting upper tract urothelial cancer (UTUC).
Methods or Background: An audit of 15 UK hospitals’ first-line imaging for visible haematuria (VH) and non-visible haematuria (NVH), and use of one-stop cystoscopy and imaging, was performed. Urology referral data from the IDENTIFY study (N = 10,896) were linked to national Hospital Episode Statistics data to estimate absolute numbers of patients receiving ultrasound or CTU first-line across England annually.
Results or Findings: Ultrasound was the first-line imaging choice for VH and NVH in 53% and 93% of hospitals respectively; other hospitals used CTU as first-line. One-stop assessment was performed in 44% of audited cases. An estimated 127,701 ultrasound and 77,880 CTU were performed across England annually, including an estimated 20% and 2% of additional CTU for patients with VH and NVH respectively receiving ultrasound first due to persistent VH.
Informed by these data, a risk-stratified imaging pathway for patients with haematuria was developed. The pathway comprised: one-stop clinic ultrasound first-line for all, additional CTU for high-risk cases (VH + age>65 + smoking history), patient-initiated follow up direct to CTU for persistent VH if not performed initially. We estimate that this pathway could results in 191,097 ultrasounds, 51,320 CTU and 73% of assessments completed with one-stop assessment, leading to an estimated 269 tonnes CO2e reduction in net greenhouse gas emissions across England for one year. Around 0.1% of patients would have UTUC missed with first-line ultrasound on this pathway.
Conclusion: Adoption of this evidence-based pathway will reduce GHG emissions whilst delivering greater risk-stratified imaging use, improving equity of healthcare access and reducing unwarranted use of CTU.
Limitations: N/A
Funding for this study: Not applicable
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Not applicable
7 min
Study on Optimization of Image Quality of Computed Tomography Urography Using Dual-layer Detector Spectral CT Virtual Monoenergetic Imaging Technique Combined with Contrast Split Bolus Protocol
Fanhui Zhao, Xi An / China
Author Block: F. Zhao, K. Li; Xi'an/CN
Purpose: To investigate the optimal keV of dual-detector spectral CT virtual monoenergetic imaging（VMI）in computed tomography urography（CTU）
Methods or Background: Hematuria patients who underwent dual-layer detector spectral CTU were collected. In the experimental group, 25mL of contrast bolus was injected first, and then 20mL of contrast bolus was injected 15 minutes later, and cortico-excretory phase CT scan was performed. In control group, non-contrast phase CT scan was performed first, then 100mL of contrast bolus was injected, and cortical, medullary and excretory phases CT scans were performed later. The experimental group was reconstructed into 40keV, 50keV, 60keV, 70keV VMI images and mixed energy images, and the excretory phase in control group was reconstructed into mixed energy image. The differences of CT value, standard deviation（SD）, signal-to-noise ratio（SNR）, contrast-to-noise ratio（CNR）, subjective score of the image quality were compared.
Results or Findings: There was no significant difference in SNR and CNR between the mixed energy images of the control group and the VMI 50keV images of the experimental group. In the score of image display effect, the VMI 50keV image of the experimental group had the highest score. In the score of filling degree of contrast bolus, VMI 40keV images in the experimental group had the highest score.The effective dose in the experimental group was about 19.96% of that in the control group, and the amount of contrast bolus in the experimental group was about 45% of that in the control group.
Conclusion: The dual-layer detector spectral CT VMI technique used in CTU can improve the image quality while reducing the amount of contrast bolus and radiation dose, and VMI 40～50keV is the best energy level for image display.
Limitations: A single-center study with a small number of cases
Funding for this study: This study was funded by the hospital by RMB 10,000
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Ethics Committee
Purpose: To investigate the optimal keV of dual-detector spectral CT virtual monoenergetic imaging（VMI）in computed tomography urography（CTU）
Methods or Background: Hematuria patients who underwent dual-layer detector spectral CTU were collected. In the experimental group, 25mL of contrast bolus was injected first, and then 20mL of contrast bolus was injected 15 minutes later, and cortico-excretory phase CT scan was performed. In control group, non-contrast phase CT scan was performed first, then 100mL of contrast bolus was injected, and cortical, medullary and excretory phases CT scans were performed later. The experimental group was reconstructed into 40keV, 50keV, 60keV, 70keV VMI images and mixed energy images, and the excretory phase in control group was reconstructed into mixed energy image. The differences of CT value, standard deviation（SD）, signal-to-noise ratio（SNR）, contrast-to-noise ratio（CNR）, subjective score of the image quality were compared.
Results or Findings: There was no significant difference in SNR and CNR between the mixed energy images of the control group and the VMI 50keV images of the experimental group. In the score of image display effect, the VMI 50keV image of the experimental group had the highest score. In the score of filling degree of contrast bolus, VMI 40keV images in the experimental group had the highest score.The effective dose in the experimental group was about 19.96% of that in the control group, and the amount of contrast bolus in the experimental group was about 45% of that in the control group.
Conclusion: The dual-layer detector spectral CT VMI technique used in CTU can improve the image quality while reducing the amount of contrast bolus and radiation dose, and VMI 40～50keV is the best energy level for image display.
Limitations: A single-center study with a small number of cases
Funding for this study: This study was funded by the hospital by RMB 10,000
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Ethics Committee
7 min
Prospective evaluation of high-resolution diffusion-weighted imaging accelerated by deep-learning reconstruction in multiparametric MRI of the prostate
Stephan Ursprung, Tübingen / Germany
Author Block: S. Ursprung1, J. Herrmann1, E. Weiland2, D. Nickel2, A. Lingg1, S. Afat1, S. Gassenmaier1; 1Tübingen/DE, 2Erlangen/DE
Purpose: Prostate MRI is a gatekeeper for more invasive investigations in prostate cancer diagnosis. This study investigates the potential of deep-learning reconstruction of high-resolution (HR) diffusion-weighted imaging (DWI) to improve image quality and lesion detectability.
Methods or Background: Prospective study comparing multiparametric MRI according to PI-RADS 2.1 specifications with standard (DWI-Std) and DWI-HR (4-fold higher in-plane resolution) on a 3T MRI-system.
Two radiologists (7yr experience) compared image quality of DWI-Std/DWI-HR qualitatively and quantitatively using the Prostate Imaging Quality Scoring System (PI-QUALv2), a 5-point Likert-scale assessing sharpness, noise, artefacts, overall impression and diagnostic confidence, and contrast-to-noise ratio (CNR) of prostatic lesions.
Results or Findings: 91 patients consented (17 exclusions for prostatectomy, 2 radiotherapy, 3 incomplete imaging); 69 patients were included. Average acquisition time for DWI-Std/DWI-HR was 04:30min/05:33min.
DWI-DL showed higher sharpness at all b-values and on ADC maps (p<0.001). This came at the cost of higher noise on b1000 and ADC (p<0.001), resulting in comparable lesion detectability (p=0.28) and PI-RADS scoring (p=1). Readers favoured DWI-HR in 47% and DWI-Std in 33%.
The PI-QUAL sub-score of DWI-Std/DWI-HR was similar (p=0.37); only the reduced SNR/Contrast in DWI-HR approached significance (p=0.054). PI-QUAL was optimal in 67%/61%, acceptable in 28%/33% and inadequate in 6%/6% when including DWI-Std/DWI-HR.
The CNR of PI-RADS 3-5 lesions in the PZ was significantly higher at b1000/on ADC maps from DWI-Std (median 10.8 vs. 10.3, p=0.002 at b1000, 10.1 vs. 7.7, p=0.0002 for ADC). The CNR between PZ/TZ was higher in DWI-Std (median 3.0 vs. 2.2; p=0.04).
Conclusion: We prospectively evaluated high-resolution DWI with DL-reconstruction, showing improved sharpness at slightly reduced CNR and maintained diagnostic performance in prostate MRI.
Limitations: This study was conducted on scanners of a single vendor. Confirmatory histology was available for PI-RADS 3+ lesions only.
Funding for this study: This study received no funding.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Tubingen University Hospital IRB
Purpose: Prostate MRI is a gatekeeper for more invasive investigations in prostate cancer diagnosis. This study investigates the potential of deep-learning reconstruction of high-resolution (HR) diffusion-weighted imaging (DWI) to improve image quality and lesion detectability.
Methods or Background: Prospective study comparing multiparametric MRI according to PI-RADS 2.1 specifications with standard (DWI-Std) and DWI-HR (4-fold higher in-plane resolution) on a 3T MRI-system.
Two radiologists (7yr experience) compared image quality of DWI-Std/DWI-HR qualitatively and quantitatively using the Prostate Imaging Quality Scoring System (PI-QUALv2), a 5-point Likert-scale assessing sharpness, noise, artefacts, overall impression and diagnostic confidence, and contrast-to-noise ratio (CNR) of prostatic lesions.
Results or Findings: 91 patients consented (17 exclusions for prostatectomy, 2 radiotherapy, 3 incomplete imaging); 69 patients were included. Average acquisition time for DWI-Std/DWI-HR was 04:30min/05:33min.
DWI-DL showed higher sharpness at all b-values and on ADC maps (p<0.001). This came at the cost of higher noise on b1000 and ADC (p<0.001), resulting in comparable lesion detectability (p=0.28) and PI-RADS scoring (p=1). Readers favoured DWI-HR in 47% and DWI-Std in 33%.
The PI-QUAL sub-score of DWI-Std/DWI-HR was similar (p=0.37); only the reduced SNR/Contrast in DWI-HR approached significance (p=0.054). PI-QUAL was optimal in 67%/61%, acceptable in 28%/33% and inadequate in 6%/6% when including DWI-Std/DWI-HR.
The CNR of PI-RADS 3-5 lesions in the PZ was significantly higher at b1000/on ADC maps from DWI-Std (median 10.8 vs. 10.3, p=0.002 at b1000, 10.1 vs. 7.7, p=0.0002 for ADC). The CNR between PZ/TZ was higher in DWI-Std (median 3.0 vs. 2.2; p=0.04).
Conclusion: We prospectively evaluated high-resolution DWI with DL-reconstruction, showing improved sharpness at slightly reduced CNR and maintained diagnostic performance in prostate MRI.
Limitations: This study was conducted on scanners of a single vendor. Confirmatory histology was available for PI-RADS 3+ lesions only.
Funding for this study: This study received no funding.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Tubingen University Hospital IRB
7 min
Ultra-Fast Biparametric MRI in Prostate Cancer Assessment: Diagnostic Performance and Image Quality Compared to Conventional Multiparametric MRI
Antonia-Maria Pausch, Zürich / Switzerland
Author Block: A-M. Pausch, V. Filleböck, C. Elsner, N. Rupp, D. Eberli, A. M. Hötker; Zurich/CH
Purpose: To compare the diagnostic performance and image quality of a deep-learning-assisted ultra-fast biparametric MRI (bpMRI) with the conventional multiparametric MRI (mpMRI) for the diagnosis of clinically significant prostate cancer (csPCa).
Methods or Background: This IRB-approved prospective single-center study enrolled 123 biopsy-naïve patients undergoing conventional mpMRI and additionally ultra-fast bpMRI at 3T between 06/2023-02/2024. Two radiologists (R1: 4 years and R2: 3 years of experience) independently assigned PI-RADS scores (PI-RADS v2.1) and assessed image quality (mPI-QUAL score) in two blinded study readouts. Weighted Cohen’s Kappa (κ) was calculated to evaluate inter-reader agreement. Diagnostic performance was analyzed using clinical data and histopathological results from clinically indicated biopsies.
Results or Findings: Inter-reader agreement was good for both mpMRI (κ = 0.83) and ultra-fast bpMRI (κ = 0.87). Both readers demonstrated high sensitivity (≥94%/≥91%, R1/R2) and NPV (≥96%/≥95%) for csPCa detection using both protocols. The more experienced reader mostly showed notably higher specificity (≥77%/≥53%), PPV (≥62%/≥45%), and diagnostic accuracy (≥82%/≥65%) compared to the less experienced reader. There was no significant difference in the diagnostic performance of correctly identifying csPCa between both protocols (p>0.05). The ultra-fast bpMRI protocol had significantly better image quality ratings (p<0.001) and achieved an 80% reduction in scan time compared to mpMRI.
Conclusion: Deep-learning-assisted ultra-fast bpMRI protocols offer a promising alternative to conventional mpMRI for diagnosing csPCa in biopsy-naïve patients with comparable inter-reader agreement and diagnostic performance at superior image quality. However, reader experience remains essential for diagnostic performance.
Limitations: The single-center design and the exclusion of some patients with a PI-RADS ≥ 3 who did not undergo biopsy may limit the generalizability of our findings.
Funding for this study: Holcim Stiftung zur Förderung der wissenschaftlichen Fortbildung
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Cantonal Ethics Commission Zurich
Purpose: To compare the diagnostic performance and image quality of a deep-learning-assisted ultra-fast biparametric MRI (bpMRI) with the conventional multiparametric MRI (mpMRI) for the diagnosis of clinically significant prostate cancer (csPCa).
Methods or Background: This IRB-approved prospective single-center study enrolled 123 biopsy-naïve patients undergoing conventional mpMRI and additionally ultra-fast bpMRI at 3T between 06/2023-02/2024. Two radiologists (R1: 4 years and R2: 3 years of experience) independently assigned PI-RADS scores (PI-RADS v2.1) and assessed image quality (mPI-QUAL score) in two blinded study readouts. Weighted Cohen’s Kappa (κ) was calculated to evaluate inter-reader agreement. Diagnostic performance was analyzed using clinical data and histopathological results from clinically indicated biopsies.
Results or Findings: Inter-reader agreement was good for both mpMRI (κ = 0.83) and ultra-fast bpMRI (κ = 0.87). Both readers demonstrated high sensitivity (≥94%/≥91%, R1/R2) and NPV (≥96%/≥95%) for csPCa detection using both protocols. The more experienced reader mostly showed notably higher specificity (≥77%/≥53%), PPV (≥62%/≥45%), and diagnostic accuracy (≥82%/≥65%) compared to the less experienced reader. There was no significant difference in the diagnostic performance of correctly identifying csPCa between both protocols (p>0.05). The ultra-fast bpMRI protocol had significantly better image quality ratings (p<0.001) and achieved an 80% reduction in scan time compared to mpMRI.
Conclusion: Deep-learning-assisted ultra-fast bpMRI protocols offer a promising alternative to conventional mpMRI for diagnosing csPCa in biopsy-naïve patients with comparable inter-reader agreement and diagnostic performance at superior image quality. However, reader experience remains essential for diagnostic performance.
Limitations: The single-center design and the exclusion of some patients with a PI-RADS ≥ 3 who did not undergo biopsy may limit the generalizability of our findings.
Funding for this study: Holcim Stiftung zur Förderung der wissenschaftlichen Fortbildung
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Cantonal Ethics Commission Zurich
7 min
Increased dose of iodine contrast media does not increase the odds of contrast-associated acute kidney injury
Felix Björn Berglund, Uppsala / Sweden
Author Block: F. B. Berglund, P. Liss, R. Frithiof; Uppsala/SE
Purpose: The aim of this study is to investigate if any of the two components of the g-I/eGFR ratio is independently associated with the development of contrast-associated acute kidney injury (CA-AKI).
Methods or Background: All patients admitted to the intensive care units (ICUs) of a tertiary hospital from January 2013 to February 2020 were retrospectively identified. Those who underwent iodine contrast media (ICM)-enhanced CT exams were included in this nested case-control study. CA-AKI was defined and staged based on the creatinine and urine output criteria set forth by the Kidney Disease Improving Global Outcomes guidelines. The two components of the ratio, the dose of ICM (measured in grams of iodine) and renal function estimated by plasma creatinine, were analyzed separately in relation to the odds of developing CA-AKI.
Results or Findings: Among the 214 patients included in the analysis PC-AKI occurred in 42 of the patients (19.6%). Median age was 61.5 years (IQR 40-73) and 59.3% were of male sex. Renal function at the day of the CT-scan differed between those developing PC-AKI (eGFR 56.9, IQR 35-87) and those that did not (eGFR 81.6, IQR 58-96). However, the dose of ICM was not associated with PC-AKI development (OR 1.31 (IQR 0.49-3.47), p=0.827).
Conclusion: In this case-control study, renal function at the day of the examination but not the administered dose of iodine contrast media was associated with PC-AKI. This suggest that including injected amount of iodine contrast media as a variable to clinically predict risk of PC-AKI is futile.
Limitations: This is a single center case-control study where only 42 critically ill patients developed CA-AKI. This reduces the generalizability of the study as well as its power.
Funding for this study: The study was supported with funding from ALF from Uppsala University Hospital, and the Swedish Research Council (2014-02569 and 2014-07606). Funding bodies had no role in the design of the study, data collection, interpretation, or in the writing of the manuscript.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Swedish Ethical Review Authority (Dnr 2017/168 with amendment 2020-00135). Declaration of Helsinki and its subsequent revisions were observed.
Purpose: The aim of this study is to investigate if any of the two components of the g-I/eGFR ratio is independently associated with the development of contrast-associated acute kidney injury (CA-AKI).
Methods or Background: All patients admitted to the intensive care units (ICUs) of a tertiary hospital from January 2013 to February 2020 were retrospectively identified. Those who underwent iodine contrast media (ICM)-enhanced CT exams were included in this nested case-control study. CA-AKI was defined and staged based on the creatinine and urine output criteria set forth by the Kidney Disease Improving Global Outcomes guidelines. The two components of the ratio, the dose of ICM (measured in grams of iodine) and renal function estimated by plasma creatinine, were analyzed separately in relation to the odds of developing CA-AKI.
Results or Findings: Among the 214 patients included in the analysis PC-AKI occurred in 42 of the patients (19.6%). Median age was 61.5 years (IQR 40-73) and 59.3% were of male sex. Renal function at the day of the CT-scan differed between those developing PC-AKI (eGFR 56.9, IQR 35-87) and those that did not (eGFR 81.6, IQR 58-96). However, the dose of ICM was not associated with PC-AKI development (OR 1.31 (IQR 0.49-3.47), p=0.827).
Conclusion: In this case-control study, renal function at the day of the examination but not the administered dose of iodine contrast media was associated with PC-AKI. This suggest that including injected amount of iodine contrast media as a variable to clinically predict risk of PC-AKI is futile.
Limitations: This is a single center case-control study where only 42 critically ill patients developed CA-AKI. This reduces the generalizability of the study as well as its power.
Funding for this study: The study was supported with funding from ALF from Uppsala University Hospital, and the Swedish Research Council (2014-02569 and 2014-07606). Funding bodies had no role in the design of the study, data collection, interpretation, or in the writing of the manuscript.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Swedish Ethical Review Authority (Dnr 2017/168 with amendment 2020-00135). Declaration of Helsinki and its subsequent revisions were observed.
7 min
Modified in-plane resolution while maintaining high image quality T2-weighted prostate MRI
Stephen J. Riederer, Rochester / United States
Author Block: S. J. Riederer1, E. Borisch1, A. Froemming1, A. Kawashima2, N. Takahashi1; 1Rochester, MN/US, 2Phoenix, AZ/US
Purpose: To determine if an axial T2-weighted spin-echo (T2-WI) sequence with modified in-plane spatial resolution could provide non-inferior performance and reduced acquisition time vs. a standard PI-RADSv2.1-compatible sequence.
Methods or Background: Both sequences used 3 mm slice thickness, 16 cm FOV, acceleration R=1.5, TR>3000, TE 150. The PI-RADS-compatible sequence used 400×230 in-plane sampling, 0.4 mm × 0.7 mm resolution (0.280 mm2 pixel area). The modified sequence used 320×280 in-plane sampling, 0.5 mm × 0.57 mm resolution (0.285 mm2 pixel area). Although the increased phase sampling of the modified sequence (280 vs. 230) required more repetitions, the reduced frequency sampling (320 vs. 400) allowed lower bandwidth and reduced averaging. The two sequences were both applied to 62 consecutive subjects identified for clinical prostate MRI. The number of slices was patient-specific but identical for the two sequences. Results were blindly reviewed by three experienced radiologists. Each series was assessed individually for Image Quality (IQ) using a 0-3 scale. For each subject the two series were also compared for overall preference on a five-point (-2, -1, 0, +1, +2) scale.
Results or Findings: Scan time depended on slice count (29 to 45). Scan time range for the PI-RADS-compatible sequence was 2:56-5:04 (median 3:54) and for the modified sequence 2:16-3:56 (median 3:01). Scan time reduction using the modified sequence was 37 to 80 sec (median 53 sec). 51/62=82.2% of the PI-RADS-compatible series and 56/62=90.3% of the modified sequence were evaluated as diagnostically interpretable (IQ=2,3). Reviewer-averaged scores showed a significant preference for the modified sequence (p<0.001).
Conclusion: Although not adherent to PI-RADSv2.1 guidelines, acquisition with essentially identical in-plane pixel area (0.28 mm2) allows 53 sec (23%) reduction in acquisition time and significantly improved reviewer preference vs. a PI-RADS-adherent sequence.
Limitations: Limited number of subjects
Funding for this study: This work was supported by NIH.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Approved by Institutional Review Board (IRB)
Purpose: To determine if an axial T2-weighted spin-echo (T2-WI) sequence with modified in-plane spatial resolution could provide non-inferior performance and reduced acquisition time vs. a standard PI-RADSv2.1-compatible sequence.
Methods or Background: Both sequences used 3 mm slice thickness, 16 cm FOV, acceleration R=1.5, TR>3000, TE 150. The PI-RADS-compatible sequence used 400×230 in-plane sampling, 0.4 mm × 0.7 mm resolution (0.280 mm2 pixel area). The modified sequence used 320×280 in-plane sampling, 0.5 mm × 0.57 mm resolution (0.285 mm2 pixel area). Although the increased phase sampling of the modified sequence (280 vs. 230) required more repetitions, the reduced frequency sampling (320 vs. 400) allowed lower bandwidth and reduced averaging. The two sequences were both applied to 62 consecutive subjects identified for clinical prostate MRI. The number of slices was patient-specific but identical for the two sequences. Results were blindly reviewed by three experienced radiologists. Each series was assessed individually for Image Quality (IQ) using a 0-3 scale. For each subject the two series were also compared for overall preference on a five-point (-2, -1, 0, +1, +2) scale.
Results or Findings: Scan time depended on slice count (29 to 45). Scan time range for the PI-RADS-compatible sequence was 2:56-5:04 (median 3:54) and for the modified sequence 2:16-3:56 (median 3:01). Scan time reduction using the modified sequence was 37 to 80 sec (median 53 sec). 51/62=82.2% of the PI-RADS-compatible series and 56/62=90.3% of the modified sequence were evaluated as diagnostically interpretable (IQ=2,3). Reviewer-averaged scores showed a significant preference for the modified sequence (p<0.001).
Conclusion: Although not adherent to PI-RADSv2.1 guidelines, acquisition with essentially identical in-plane pixel area (0.28 mm2) allows 53 sec (23%) reduction in acquisition time and significantly improved reviewer preference vs. a PI-RADS-adherent sequence.
Limitations: Limited number of subjects
Funding for this study: This work was supported by NIH.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Approved by Institutional Review Board (IRB)
7 min
CEST Imaging vs. DWI with and without CEST Imaging: Capability for Distinguishing Malignant from Benign Prostatic Areas
Yoshiharu Ohno, Toyoake / Japan
Author Block: T. Ueda, H. Nagata, M. Nomura, T. Yoshikawa, D. Takenaka, Y. Ozawa, Y. Ohno; Toyoake/JP
Purpose: 3D Chemical exchange saturation transfer (CEST) imaging is recently developed to obtain CEST information within entire tumor. The purpose of this study was to compare the capability for distinguishing malignant from benign prostatic areas among 3D CEST imaging, diffusion weighted imaging (DWI) and combined both information.
Methods or Background: Fifty-two suspected prostatic cancer patients underwent DWI at b value as 0 and 1500 s/mm2 and 3D CEST imaging, surgical treatments and pathological examinations. According to the pathological results, 154 areas were determined as malignant prostatic areas, and 154 out of 470 areas were computationally selected as benign prostatic areas. On each 3D CEST imaging, magnetization transfer ratio asymmetry (MTRasym) at 3.5 ppm map was generated. Then, 308 ROIs were placed over malignant or benign areas on each map, and MTRasym and ADC values were determined. Each index was compared between malignant and benign areas by Student’s t-test. ROC analysis was performed to compare diagnostic performance among MTRasym, ADC and combined discriminators. Finally, sensitivity, specificity and accuracy were compared among all methods by McNemar’s test.
Results or Findings: MTRasym and ADC of malignant area had significant differences with those of benign area (MTRasym: p<0.0001, ADC: p<0.0001). Area under the curves (AUC) of combined discriminators (AUC=0.86) was significantly better than that of MTRasym (AUC=0.81, p=0.001) and ADC (AUC=0.76, p<0.0001). Specificity (SP) and accuracy (AC) of combined discriminators (SP: 72.1%, AC: 78.6%) were significantly higher than those of MTRasym (SP: 60.4%, p<0.0001; AC: 73.1%, p<0.0001) and ADC (SP: 64.2%, p<0.0001; AC: 74.0%, p<0.0001).
Conclusion: 3D CEST imaging is considered at least as valuable as DWI and can improve capability for differentiation of malignant from benign prostatic areas with DWI.
Limitations: LImited study population
Funding for this study: Research grants from Canon Medical Systems
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Fujita Health University Hospital
Purpose: 3D Chemical exchange saturation transfer (CEST) imaging is recently developed to obtain CEST information within entire tumor. The purpose of this study was to compare the capability for distinguishing malignant from benign prostatic areas among 3D CEST imaging, diffusion weighted imaging (DWI) and combined both information.
Methods or Background: Fifty-two suspected prostatic cancer patients underwent DWI at b value as 0 and 1500 s/mm2 and 3D CEST imaging, surgical treatments and pathological examinations. According to the pathological results, 154 areas were determined as malignant prostatic areas, and 154 out of 470 areas were computationally selected as benign prostatic areas. On each 3D CEST imaging, magnetization transfer ratio asymmetry (MTRasym) at 3.5 ppm map was generated. Then, 308 ROIs were placed over malignant or benign areas on each map, and MTRasym and ADC values were determined. Each index was compared between malignant and benign areas by Student’s t-test. ROC analysis was performed to compare diagnostic performance among MTRasym, ADC and combined discriminators. Finally, sensitivity, specificity and accuracy were compared among all methods by McNemar’s test.
Results or Findings: MTRasym and ADC of malignant area had significant differences with those of benign area (MTRasym: p<0.0001, ADC: p<0.0001). Area under the curves (AUC) of combined discriminators (AUC=0.86) was significantly better than that of MTRasym (AUC=0.81, p=0.001) and ADC (AUC=0.76, p<0.0001). Specificity (SP) and accuracy (AC) of combined discriminators (SP: 72.1%, AC: 78.6%) were significantly higher than those of MTRasym (SP: 60.4%, p<0.0001; AC: 73.1%, p<0.0001) and ADC (SP: 64.2%, p<0.0001; AC: 74.0%, p<0.0001).
Conclusion: 3D CEST imaging is considered at least as valuable as DWI and can improve capability for differentiation of malignant from benign prostatic areas with DWI.
Limitations: LImited study population
Funding for this study: Research grants from Canon Medical Systems
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Fujita Health University Hospital
7 min
The comparison between virtual non-contrast and true non-contrast imaging of adrenal masses on photon-counting CT
Xin Bai, Beijing / China
Author Block: X. Bai, G. Zhang, X. Zhang, J. Zhang, L. Chen, Q. Peng, E. Guo, H. Sun, Z. Jin; Beijing/CN
Purpose: To investigate the differences in CT attenuation and radiomics features between virtual non-contrast (VNC) and true non-contrast (TNC) of adrenal masses on photon-counting CT (PCCT).
Methods or Background: Patients with adrenal masses who underwent unenhanced and portal-venous-phase PCCT were included. Image reconstructions of portal-venous phase were performed, including Conventional VNC (VNCconv) and PureCalcium VNC (VNCpc) algorithms. For two dimensional (2D) measurements, we measured CT attenuation of adrenal mass at the largest slice on TNC, VNCconv, and VNCpc images, respectively. Semiautomatic segmentations of adrenal masses were performed to extract three-dimensional (3D) CT attenuation and radiomics features on TNC and VNC. The paired t-test, Bland–Altman plots and intraclass correlation efficient (ICC) were used for statistical analyses.
Results or Findings: The study consisted of 54 patients (27 female, mean age 45.3 years) with 68 adrenal lesions. CT attenuation on VNCconv and VNCpc was higher than that on TNC (Mean differences, 2D: 8.03 HU for VNCconv and 5.76 HU for VNCpc, 3D: 8.75 HU for VNCconv and 6.89 HU for VNCpc). The proportion of lipid-rich adenomas (TNC < 10 HU) correctly classified by VNCconv and VNCpc was 26.1% (6/23) and 39.1% (9/23), respectively. TNC, VNCconv, and VNCpc attenuation did not differ significantly between 2D and 3D measurements (all P ＞ 0.05). The ICCs of first-order features, shape features and texture features between TNC and VNCconv were 0.625, 0.820 and 0.591, respectively.
Conclusion: The VNC algorithms of PCCT overestimated CT attenuation. CT attenuation at the largest slice can replace 3D attenuation. VNC and TNC have excellent agreement on shape features and average agreement on first-order features and texture features.
Limitations: The limitations of the study are the study sample is relatively small and the retrospective study may have a selection bias.
Funding for this study: Funding was provided by the National High-Level Hospital Clinical Research Funding (2022-PUMCH-B-069, 2022-PUMCH-A-033 and 2022-PUMCH-A-035), CAMS Innovation Fund for Medical Sciences (2022-I2M-C&T-B-019) and Beijing Municipal Natural Science Foundation (L232133).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Institutional Review Board (No. 23PJ1487).
Purpose: To investigate the differences in CT attenuation and radiomics features between virtual non-contrast (VNC) and true non-contrast (TNC) of adrenal masses on photon-counting CT (PCCT).
Methods or Background: Patients with adrenal masses who underwent unenhanced and portal-venous-phase PCCT were included. Image reconstructions of portal-venous phase were performed, including Conventional VNC (VNCconv) and PureCalcium VNC (VNCpc) algorithms. For two dimensional (2D) measurements, we measured CT attenuation of adrenal mass at the largest slice on TNC, VNCconv, and VNCpc images, respectively. Semiautomatic segmentations of adrenal masses were performed to extract three-dimensional (3D) CT attenuation and radiomics features on TNC and VNC. The paired t-test, Bland–Altman plots and intraclass correlation efficient (ICC) were used for statistical analyses.
Results or Findings: The study consisted of 54 patients (27 female, mean age 45.3 years) with 68 adrenal lesions. CT attenuation on VNCconv and VNCpc was higher than that on TNC (Mean differences, 2D: 8.03 HU for VNCconv and 5.76 HU for VNCpc, 3D: 8.75 HU for VNCconv and 6.89 HU for VNCpc). The proportion of lipid-rich adenomas (TNC < 10 HU) correctly classified by VNCconv and VNCpc was 26.1% (6/23) and 39.1% (9/23), respectively. TNC, VNCconv, and VNCpc attenuation did not differ significantly between 2D and 3D measurements (all P ＞ 0.05). The ICCs of first-order features, shape features and texture features between TNC and VNCconv were 0.625, 0.820 and 0.591, respectively.
Conclusion: The VNC algorithms of PCCT overestimated CT attenuation. CT attenuation at the largest slice can replace 3D attenuation. VNC and TNC have excellent agreement on shape features and average agreement on first-order features and texture features.
Limitations: The limitations of the study are the study sample is relatively small and the retrospective study may have a selection bias.
Funding for this study: Funding was provided by the National High-Level Hospital Clinical Research Funding (2022-PUMCH-B-069, 2022-PUMCH-A-033 and 2022-PUMCH-A-035), CAMS Innovation Fund for Medical Sciences (2022-I2M-C&T-B-019) and Beijing Municipal Natural Science Foundation (L232133).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Institutional Review Board (No. 23PJ1487).
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This session is accredited with 1 CME credit.
Atul B Shinagare
Boston / United States
Simon Lambracos
London / United KingdomFanhui Zhao
Xi An / ChinaStephan Ursprung
Tübingen / GermanyAntonia-Maria Pausch
Zürich / SwitzerlandFelix Björn Berglund
Uppsala / SwedenStephen J. Riederer
Rochester / United StatesYoshiharu Ohno
Toyoake / JapanXin Bai
Beijing / China