Faculty Bibliography

OBJECTIVE:The aim of this study was to compare portal venous phase photon-counting CT (PCCT) using 20 cc less than weight-based contrast dosing with energy-integrating detector CT (EID-CT) using weight-based dosing by quantitative and qualitative analysis. METHODS:Fifty adult patients who underwent a reduced intravenous contrast dose portal venous phase PCCT from May 1, 2023, to August 10, 2023, and a prior portal-venous EID-CT with weight-based contrast dosing were retrospectively identified. Hounsfield units (HU) and noise (SD of HU) were obtained from region-of-interest measurements on 70-keV PCCT and EID-CT in 4 hepatic segments, the main and right portal vein, and both paraspinal muscles. Signal-to-noise and contrast-to-noise ratios were computed. Three abdominal radiologists qualitatively assessed overall image quality, hepatic enhancement, and confidence for metastasis identification on 5-point Likert scales. Readers also recorded the presence/absence of hepatic metastases. Quantitative variables were compared with paired t tests, and multiple comparisons were accounted for with a Bonferroni-adjusted α level of .0016. Ordinal logistic regression was used to evaluate qualitative assessments. Interreader agreement for hepatic metastases was calculated using Fleiss' κ. RESULTS:Fifty patients (32 women; mean [SD] age, 64 [13] years) were included. There was no significant difference in hepatic HU, portal vein HU, noise, and signal-to-noise or contrast-to-noise ratio between reduced contrast dose portal venous phase PCCT versus EID-CT (all Ps > 0.0016). Image quality, degree of hepatic enhancement, and confidence for metastasis identification were not different for reduced dose PCCT 70-keV images and EID-CT (P = 0.06-0.69). κ Value for metastasis identification was 0.86 (95% confidence interval, 0.70-1.00) with PCCT and 0.78 (95% confidence interval, 0.59-0.98) with EID-CT. CONCLUSION/CONCLUSIONS:Reduced intravenous contrast portal venous phase PCCT 70-keV images had similar attenuation and image quality as EID-CT with weight-based dosing. Metastases were identified with near-perfect agreement in reduced dose PCCT 70-keV images.

PURPOSE/OBJECTIVE:This study aimed to compare the image quality of portal venous phase-derived virtual noncontrast (VNC) images from photon-counting computed tomography (PCCT) with energy-integrating dual-energy computed tomography (EI-DECT) in the same patient using quantitative and qualitative analyses. METHODS:Consecutive patients retrospectively identified with available portal venous phase-derived VNC images from both PCCT and EI-DECT were included. Patients without available VNC in picture archiving and communication system in PCCT or prior EI-DECT and non-portal venous phase acquisitions were excluded. Three fellowship-trained radiologists blinded to VNC source qualitatively assessed VNC images on a 5-point scale for overall image quality, image noise, small structure delineation, noise texture, artifacts, and degree of iodine removal. Quantitative assessment used region-of-interest measurements within the aorta at 4 standard locations, both psoas muscles, both renal cortices, spleen, retroperitoneal fat, and inferior vena cava. Attenuation (Hounsfield unit), quantitative noise (Hounsfield unit SD), contrast-to-noise ratio (CNR) (CNRvascular, CNRkidney, CNRspleen, CNRfat), signal-to-noise ratio (SNR) (SNRvascular, SNRkidney, SNRspleen, SNRfat), and radiation dose were compared between PCCT and EI-DECT with the Wilcoxon signed rank test. A P < 0.05 indicated statistical significance. RESULTS:A total of 74 patients (27 men; mean ± SD age, 63 ± 13 years) were included. Computed tomography dose index volumes for PCCT and EI-DECT were 9.2 ± 3.5 mGy and 9.4 ± 9.0 mGy, respectively (P = 0.06). Qualitatively, PCCT VNC images had better overall image quality, image noise, small structure delineation, noise texture, and fewer artifacts (all P < 0.00001). Virtual noncontrast images from PCCT had lower attenuation (all P < 0.05), noise (P = 0.006), and higher CNR (P < 0.0001-0.04). Contrast-enhanced structures had lower SNR on PCCT (P = 0.001, 0.002), reflecting greater contrast removal. The SNRfat (nonenhancing) was higher for PCCT than EI-DECT (P < 0.00001). CONCLUSIONS:Virtual noncontrast images from PCCT had improved image quality, lower noise, improved CNR and SNR compared with those derived from EI-DECT.

PURPOSE/OBJECTIVE:To quantitatively and qualitatively compare the degree of iodine removal in the collecting system from PCCT urographic phase-derived virtual noncontrast (VNC) images obtained at 140 kV versus 120 kV. METHODS:A retrospective PACS search identified adult patients (>18 years) who underwent a PCCT urogram for hematuria from 4/2022 to 4/2023 with available urographic phase-derived VNC images in PACS. Tube voltage (120 kV, 140 kV), body mass index, CTDIvol, dose length product (DLP), and size-specific dose estimate (SSDE) were recorded. Hounsfield Unit (HU) in both renal pelvises and the urinary bladder on urographic-derived VNC were recorded. Three radiologists qualitatively assessed the degree of iodine removal (renal pelvis, urinary bladder) and diagnostic confidence for urinary stone detection. Continuous variables were compared for 140 kV versus 120 kV with the Wilcoxon rank sum test. A p < .05 indicated statistical significance. RESULTS:63 patients (34 male; median (Q1, Q3) age: 30 (26, 34) years; 140 kV/120 kV: 30 patients/33 patients) were included. BMI, CTDIvol, DLP, and SSDE were not different for 140 kV and 120 kV (all p > .05). Median (Q1, Q3) collecting system HU (renal pelvis and bladder) was 0.9 (- 3.6, 4.4) HU at 140 kV and 10.5 (3.6, 26.7) HU at 120 kV (p = .04). Diagnostic confidence for urinary calculi was 4.6 [1.1] at 140 kV and 4.1 [1.4] at 120 kV (p = .005). Diagnostic confidence was 5/5 (all readers) in 82.2% (74/90) at 140 kV and 59.6% (59/99) at 120 kV (p < .001). CONCLUSION/CONCLUSIONS:PCCT urographic phase-derived VNC images obtained at 140 kV had better collecting system iodine removal than 120 kV with similar patient radiation exposure. With excellent PCCT urographic phase iodine removal at 140 kV, consideration can be made to utilize a single-phase CT urogram in young patients.

INTRODUCTION/BACKGROUND:Prostate cancer diffusion weighted imaging (DWI) MRI is typically performed at high-field strength (3.0 T) in order to overcome low signal-to-noise ratio (SNR). In this study, we demonstrate the feasibility of prostate DWI at low field enabled by random matrix theory (RMT)-based denoising, relying on the MP-PCA algorithm applied during image reconstruction from multiple coils. METHODS:Twenty-one volunteers and 2 prostate cancer patients were imaged with a 6-channel pelvic surface array coil and an 18-channel spine array on a prototype 0.55 T system created by ramping down a commercial magnetic resonance imaging system (1.5 T MAGNETOM Aera Siemens Healthcare) with 45 mT/m gradients and 200 T/m/s slew rate. Diffusion-weighted imagings were acquired with 4 non-collinear directions, for which b = 50 s/mm2 was used with 8 averages and b = 1000 s/mm2 with 40 averages; 2 extra b = 50 s/mm2 were used as part of the dynamic field correction. Standard and RMT-based reconstructions were applied on DWI over different ranges of averages. Accuracy/precision was evaluated using the apparent diffusion coefficient (ADC), and image quality was evaluated over 5 separate reconstructions by 3 radiologists with a 5-point Likert scale. For the 2 patients, we compare image quality and lesion visibility of the RMT reconstruction versus the standard one on 0.55 T and on clinical 3.0 T. RESULTS:The RMT-based reconstruction in this study reduces the noise floor by a factor of 5.8, thereby alleviating the bias on prostate ADC. Moreover, the precision of the ADC in prostate tissue after RMT increases over a range of 30%-130%, with the increase in both signal-to-noise ratio and precision being more prominent for a low number of averages. Raters found that the images were consistently of moderate to good overall quality (3-4 on the Likert scale). Moreover, they determined that b = 1000 s/mm2 images from a 1:55-minute scan with the RMT-based reconstruction were on par with the corresponding images from a 14:20-minute scan with standard reconstruction. Prostate cancer was visible on ADC and calculated b = 1500 images even with the abbreviated 1:55 scan reconstructed with RMT. CONCLUSIONS:Prostate imaging using DWI is feasible at low field and can be performed more rapidly with noninferior image quality compared with standard reconstruction.

PURPOSE/OBJECTIVE:Given that ileal pouch-anal anastomosis (IPAA) surgery is a technically challenging and high-morbidity procedure, there are numerous pertinent imaging findings that need to be clearly and efficiently communicated to the IBD surgeons for essential patient management and surgical planning. Structured reporting has been increasingly used over the past decade throughout various radiology subspecialties to improve reporting clarity and completeness. We compare structured versus non-structured reporting of pelvic MRI for ileal pouch to evaluate for clarity and effectiveness. METHODS:164 consecutive pelvic MRI's for ileal pouch evaluation, excluding subsequent exams for the same patient, acquired between 1/1/2019 and 7/31/2021 at one institution were included, before and after implementation (11/15/2020) of a structured reporting template, which was created with institutional IBD surgeons. Reports were assessed for the presence of 18 key features required for complete ileal pouch assessment: anastomosis (IPAA, tip of J, pouch body), cuff (length, cuffitis), pouch body (size, pouchitis, stricture), pouch inlet/pre-pouch ileum (stricture, inflammation, sharp angulation), pouch outlet (stricture), peripouch mesentery (position, mesentery twist), pelvic abscess, peri-anal fistula, pelvic lymph nodes, and skeletal abnormalities. Subgroup analysis was performed based on reader experience and divided into three categories: experienced (n = 2), other intra-institutional (n = 20), or affiliate site (n = 6). RESULTS:57 (35%) structured and 107 (65%) non-structured pelvic MRI reports were reviewed. Structured reports contained 16.6 [SD:4.0] key features whereas non-structured reports contained 6.3 [SD:2.5] key features (p < .001). The largest improvement following template implementation was for reporting sharp angulation of the pouch inlet (91.2% vs. 0.9%, p < .001), tip of J suture line and pouch body anastomosis (both improved to 91.2% from 3.7%). Structured versus non-structured reports contained mean 17.7 versus 9.1 key features for experienced readers, 17.0 versus 5.9 for other intra-institutional readers, and 8.7 versus 5.3 for affiliate site readers. CONCLUSION/CONCLUSIONS:Structured reporting of pelvic MRI guides a systematic search pattern and comprehensive evaluation of ileal pouches, and therefore facilitates surgical planning and clinical management. This standardized reporting template can serve as baseline at other institutions for adaptation based on specific radiology and surgery preferences, fostering a collaborative environment between radiology and surgery, and ultimately improving patient care.

BACKGROUND:Three-dimensional (3D) printed anatomic models can facilitate presurgical planning by providing surgeons with detailed knowledge of the exact location of pertinent anatomical structures. Although 3D printed anatomic models have been shown to be useful for pre-operative planning, few studies have demonstrated how these models can influence quantitative surgical metrics. OBJECTIVE:To prospectively assess whether patient-specific 3D printed prostate cancer models can improve quantitative surgical metrics in patients undergoing robotic-assisted radical prostatectomy (RARP). METHODS:Patients with MRI-visible prostate cancer (PI-RADS V2 ≥ 3) scheduled to undergo RARP were prospectively enrolled in our IRB approved study (n = 82). Quantitative surgical metrics included the rate of positive surgical margins (PSMs), operative times, and blood loss. A qualitative Likert scale survey to assess understanding of anatomy and confidence regarding surgical approach was also implemented. RESULTS:The rate of PSMs was lower for the 3D printed model group (8.11%) compared to that with imaging only (28.6%), p = 0.128. The 3D printed model group had a 9-min reduction in operating time (213 ± 42 min vs. 222 ± 47 min) and a 5 mL reduction in average blood loss (227 ± 148 mL vs. 232 ± 114 mL). Surgeon anatomical understanding and confidence improved after reviewing the 3D printed models (3.60 ± 0.74 to 4.20 ± 0.56, p = 0.62 and 3.86 ± 0.53 to 4.20 ± 0.56, p = 0.22). CONCLUSIONS:3D printed prostate cancer models can positively impact quantitative patient outcomes such as PSMs, operative times, and blood loss in patients undergoing RARP.

PURPOSE/OBJECTIVE:The aim of this study was to evaluate the diagnostic performance of preoperative cross-sectional imaging findings using the SAR-AGA definitions in Crohn's disease (CD) patients who underwent ileocolic resection (ICR) with and without surgically complex ileocolic CD (CIC-CD). METHODS:69 CD patients [38 men; mean (± SD) age: 40.6 (16.2) years] who underwent ICR were retrospectively classified by surgical complexity by a colorectal surgeon using operative findings. CIC-CD was defined as ileal CD, not confined to the distal ileum. Two radiologists retrospectively evaluated the preoperative imaging for the presence and type of penetrating disease, stricture, or probable stricture using the SAR-AGA consensus definitions. The diagnostic performance of preoperative imaging findings was compared for patients with and without CIC-CD. Estimated blood loss (EBL), operative time (OT), conversion to open surgery, diversion, and length of hospital stay (LOS) were compared. RESULTS:60.9% had CIC-CD and 79.7% underwent primary ICR. Penetrating disease was more common in patients with than without CIC-CD (76.2% vs. 40.7%, p = 0.0048) and similar among primary versus redo ICR (p = 0.12). Patients with CIC-CD had more complex fistulas (59.5% vs. 11.1%; p < 0.0001) and fewer simple fistulas (2.4% vs. 18.5%; p = 0.03) than those without. Mesenteric findings (abscess, inflammatory mass) were more frequent in patients with (35.7%) than without (0%) (p = 0.0002) CIC-CD. Stricture and probable stricture were similar (p = 0.59). CIC-CD patients had greater EBL (178 cc vs. 57 cc, p = 0.006), conversion rates (30% vs. 0%, p = 0.0026), and diversion (80% vs. 52%, p = 0.04). CONCLUSION/CONCLUSIONS:Complex fistula, mesenteric abscess, or inflammatory mass defined by the SAR-AGA guidelines suggests CIC-CD. ICR for CIC-CD had greater EBL, conversion to open surgery, and diversion.

PURPOSE/OBJECTIVE:Fat-suppressed T2-weighted imaging (T2-FS) requires a long scan time and can be wrought with motion artifacts, urging the development of a shorter and more motion robust sequence. We compare the image quality of a single-shot T2-weighted MRI prototype with deep-learning-based image reconstruction (DL HASTE-FS) with a standard T2-FS sequence for 3 T liver MRI. METHODS:41 consecutive patients with 3 T abdominal MRI examinations including standard T2-FS and DL HASTE-FS, between 5/6/2020 and 11/23/2020, comprised the study cohort. Three radiologists independently reviewed images using a 5-point Likert scale for artifact and image quality measures, while also assessing for liver lesions. RESULTS:DL HASTE-FS acquisition time was 54.93 ± 16.69, significantly (p < .001) shorter than standard T2-FS (114.00 ± 32.98 s). DL HASTE-FS received significantly higher scores for sharpness of liver margin (4.3 vs 3.3; p < .001), hepatic vessel margin (4.2 vs 3.3; p < .001), pancreatic duct margin (4.0 vs 1.9; p < .001); in-plane (4.0 vs 3.2; p < .001) and through-plane (3.9 vs 3.4; p < .001) motion artifacts; other ghosting artifacts (4.3 vs 2.9; p < .001); and overall image quality (4.0 vs 2.9; p < .001), in addition to receiving a higher score for homogeneity of fat suppression (3.7 vs 3.4; p = .04) and liver-fat contrast (p = .03). For liver lesions, DL HASTE-FS received significantly higher scores for sharpness of lesion margin (4.4 vs 3.7; p = .03). CONCLUSION/CONCLUSIONS:Novel single-shot T2-weighted MRI with deep-learning-based image reconstruction demonstrated superior image quality compared with the standard T2-FS sequence for 3 T liver MRI, while being acquired in less than half the time.

PURPOSE/OBJECTIVE:To implement a more efficient standardized computed tomography (CT) protocoling system for emergency department (ED) patients in order to improve resident work satisfaction and wellness, and decrease lag time between ordering and protocoling a study. METHODS AND MATERIALS/METHODS:Residents recorded lag times between time of order and time of protocol for 176 CT scans between November 2018 and January 2019. Pre- and postintervention resident surveys of 7 questions utilizing a 5-point Likert scale were used to assess the perceived efficiency and overall satisfaction with the protocolling system. CT technologists received a 2-step Standardized ED CT Protocoling Guidance Sheet for common indications and would consult the radiologist for any questions. RESULTS:Lag time between order and protocol averaged 17.8 minutes. Postintervention surveys demonstrated that residents were more satisfied with the new system (100% vs 6.1%), had an overall higher job satisfaction in the ED (91% vs 12.1%), thought the system was more efficient for a single study (100% vs 15.2%) and for an entire shift (100% vs 6.1%), volume of studies was maximized (91% vs 6.1%), and the workflow allowed residents to focus on interpreting studies and communicating findings (91% vs 3%). CONCLUSION/CONCLUSIONS:The implementation of an auto-protocolling system at our institution's ED took a system which was disruptive, inefficient, and unreliable, and eliminated both lag time and variation in time between ordering and protocoling, improving time to final report. It simultaneously decreased interruptions, allowing residents to focus on study interpretation, which increased resident work satisfaction, wellness, and educational benefit.