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Purpose@#This study aimed to evaluate the feasibility of measuring liver fat using the volumetric measurement method (Fatvol) by comparing it with the conventional 27-regions of interest drawing method (Fatroi). @*Materials and Methods@#This retrospective study included 67 patients who underwent liver magnetic resonance imaging with fat quantification in August or September 2020.Two experienced abdominal radiologists measured the proton density fat fraction (PDFF) of the liver using the mDIXON-Quant sequence for each of two methods. The PDFF was measured twice with each method at intervals of at least 4 weeks to avoid recall bias. Measurement times were recorded. The intra-class correlation coefficient (ICC) was calculated for intra-exam repeatability, inter-reviewer reproducibility, and inter-exam agreement. @*Results@#Measurement times for Fatvol were significantly shorter than for Fatroi. Measurement times for Fatroi and Fatvol, respectively, for reviewer A were 209.4 ± 55.1 s and 137.2 ± 51.5 s in session 1, and 180.9 ± 37.3 s and 127.0 ± 46.1 s in session 2. For reviewer B, the times were 190.7 ± 30.1 s and 74.8 ± 27.4 s in session 1, and 174.6 ± 21.8 s and 64.1 ± 17.5 s in session 2. In all cases, p < 0.001. The mean PDFF values were 7.2% ± 6.4% and 7.2% ± 6.5% (sessions 1 and 2, respectively) for Fatroi and 7.4% ± 6.0% and 7.3% ± 6.1% for Fatvol for reviewer A. For reviewer B, they were 7.1% ± 6.6% and 7.1% ± 6.6% for Fatroi and 7.4% ± 5.8% and 7.4% ± 5.8% for Fatvol. The ICCs between measurement methods (0.998 and 0.995 for reviewers A and B, respectively), for Fatvol within each reviewer (0.999 and 1.000 in sessions 1 and 2, respectively), and between reviewers (0.999) were excellent. @*Conclusion@#The measurement time could be significantly reduced using Fatvol compared to Fatroi while maintaining the consistency of the liver fat measurement values.
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Objective@#To investigate molecular and functional consequences of additional exposures to iodine- or gadolinium-based contrast agents within 24 hours from the initial intravenous administration of iodine-based contrast agents through an animal study. @*Materials and Methods@#Fifty-six Sprague–Dawley male rats were equally divided into eight groups: negative control, positive control (PC) with single-dose administration of CT contrast agent, and additional administration of either CT or MR contrast agents 2, 4, or 24 hours from initial CT contrast agent injection. A 12 µL/g of iodinated contrast agent or a 0.47 µL/g of gadoliniumbased contrast agent were injected into the tail vein. Serum levels of blood urea nitrogen, creatinine, cystatin C (Cys C), and malondialdehyde (MDA) were measured. mRNA and protein levels of kidney injury molecule-1 (KIM-1) and neutrophil gelatinaseassociated lipocalin (NGAL) were evaluated. @*Results@#Levels of serum creatinine (SCr) were significantly higher in repeated CT contrast agent injection groups than in PC (0.21 ± 0.02 mg/dL for PC; 0.40 ± 0.02, 0.34 ± 0.03, and 0.41 ± 0.10 mg/dL for 2-, 4-, and 24-hour interval groups, respectively; P 0.99). Additional doses of MR contrast agent did not make significant changes compared to PC in SCr (P > 0.99), Cys C (P = 0.262), and MDA (P = 0.139–0.771) levels. mRNA and protein levels of KIM-1 and NGAL were not significantly different among additional CT or MR contrast agent groups (P > 0.05). @*Conclusion@#A sufficient time interval, probably more than 24 hours, between repeated contrast-enhanced CT examinations may be necessary to avoid deterioration in renal function. However, conducting contrast-enhanced MRI on the same day as contrast-enhanced CT may not induce clinically significant kidney injury.
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Objective@#To evaluate the image quality and lesion detectability of lower-dose CT (LDCT) of the abdomen and pelvis obtained using a deep learning image reconstruction (DLIR) algorithm compared with those of standard-dose CT (SDCT) images. @*Materials and Methods@#This retrospective study included 123 patients (mean age ± standard deviation, 63 ± 11 years;male:female, 70:53) who underwent contrast-enhanced abdominopelvic LDCT between May and August 2020 and had prior SDCT obtained using the same CT scanner within a year. LDCT images were reconstructed with hybrid iterative reconstruction (h-IR) and DLIR at medium and high strengths (DLIR-M and DLIR-H), while SDCT images were reconstructed with h-IR. For quantitative image quality analysis, image noise, signal-to-noise ratio, and contrast-to-noise ratio were measured in the liver, muscle, and aorta. Among the three different LDCT reconstruction algorithms, the one showing the smallest difference in quantitative parameters from those of SDCT images was selected for qualitative image quality analysis and lesion detectability evaluation. For qualitative analysis, overall image quality, image noise, image sharpness, image texture, and lesion conspicuity were graded using a 5-point scale by two radiologists. Observer performance in focal liver lesion detection was evaluated by comparing the jackknife free-response receiver operating characteristic figures-of-merit (FOM). @*Results@#LDCT (35.1% dose reduction compared with SDCT) images obtained using DLIR-M showed similar quantitative measures to those of SDCT with h-IR images. All qualitative parameters of LDCT with DLIR-M images but image texture were similar to or significantly better than those of SDCT with h-IR images. The lesion detectability on LDCT with DLIR-M images was not significantly different from that of SDCT with h-IR images (reader-averaged FOM, 0.887 vs. 0.874, respectively; p = 0.581). @*Conclusion@#Overall image quality and detectability of focal liver lesions is preserved in contrast-enhanced abdominopelvic LDCT obtained with DLIR-M relative to those in SDCT with h-IR.
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Purpose@#Locally advanced rectal cancer (LARC) is managed by chemoradiotherapy (CRT), followed by surgery. Herein we reported patients with metastases during or after CRT. @*Methods@#Data of patients with LARC who received CRT from 2008 to 2017 were reviewed. Patients with metastases after CRT were included. Those with metastatic tumors at the initial diagnosis were excluded. @*Results@#Fourteen patients (1.3%) of 1,092 who received CRT presented with metastases. Magnetic resonance circumferential resection margin (mrCRM) and mesorectal lymph nodes (LNs) were positive in 12 patients (85.7%). Meanwhile, magnetic resonance extramural vascular invasion (mrEMVI) was positive in 10 patients (71.4%). Magnetic resonance tumor regression grade (mrTRG) 4 and mrTRG5 was detected in 5 and 1 patient respectively. Ten patients (71.4%) underwent combined surgery and 3 (21.4%) received palliative chemotherapy. @*Conclusion@#Patients with metastases after CRT showed a higher rate of positive mrCRM, mrEMVI, mesorectal LNs, and poor tumor response. Further studies with a large number of patients are necessary for better survival outcomes in LARC.
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Objective@#To compare the performance of the deep learning-based lesion detection algorithm (DLLD) in detecting liver metastasis with that of radiologists. @*Materials and Methods@#This clinical retrospective study used 4386-slice computed tomography (CT) images and labels from a training cohort (502 patients with colorectal cancer [CRC] from November 2005 to December 2010) to train the DLLD for detecting liver metastasis, and used CT images of a validation cohort (40 patients with 99 liver metastatic lesions and 45 patients without liver metastasis from January 2011 to December 2011) for comparing the performance of the DLLD with that of readers (three abdominal radiologists and three radiology residents). For per-lesion binary classification, the sensitivity and false positives per patient were measured. @*Results@#A total of 85 patients with CRC were included in the validation cohort. In the comparison based on per-lesion binary classification, the sensitivity of DLLD (81.82%, [81/99]) was comparable to that of abdominal radiologists (80.81%, p = 0.80) and radiology residents (79.46%, p = 0.57). However, the false positives per patient with DLLD (1.330) was higher than that of abdominal radiologists (0.357, p < 0.001) and radiology residents (0.667, p < 0.001). @*Conclusion@#DLLD showed a sensitivity comparable to that of radiologists when detecting liver metastasis in patients initially diagnosed with CRC. However, the false positives of DLLD were higher than those of radiologists. Therefore, DLLD could serve as an assistant tool for detecting liver metastasis instead of a standalone diagnostic tool.
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Purpose@#To assess associations between surveillance intervals in a national hepatocellular carcinoma (HCC) surveillance program and receiving curative treatment and mortality using nationwide cohort data for Korea. @*Materials and Methods@#Using the National Health Insurance Service Database of Korea, we retrospectively identified 3201852 patients, the target population of the national HCC surveillance program, between 2008 and 2017. After exclusion, a total of 64674 HCC patients were divided based on surveillance intervals: never screened, ≤6 months (6M), 7–12 months (1Y), 13–24 months (2Y), and 25–36 months (3Y). Associations for surveillance interval with the chance to receive curative therapy and all-cause mortality were analyzed. @*Results@#The 6M group (51.9%) received curative therapy more often than the other groups (1Y, 48.3%; 2Y, 43.8%; 3Y, 41.3%; never screened, 34.5%). Odds ratio for receiving curative therapy among the other surveillance interval groups (1Y, 0.87; 2Y, 0.76; 3Y, 0.77;never screened, 0.57; p<0.001) were significantly lower than that of the 6M group. The hazard ratios (HRs) of all-cause mortality were 1.07, 1.14, and 1.37 for 2Y, 3Y, and never screened groups. The HR for the 1Y group (0.96; p=0.092) was not significantly different, and it was lower (0.91; p<0.001) than that of the 6M group after adjustment for lead-time bias. Curative therapy was associated with survival benefits (HR, 0.26; p<0.001). @*Conclusion@#HCC surveillance, especially at a surveillance interval of 6 months, increases the chance to receive curative therapy.
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Purpose@#Locally advanced rectal cancer (LARC) is managed by chemoradiotherapy (CRT), followed by surgery. Herein we reported patients with metastases during or after CRT. @*Methods@#Data of patients with LARC who received CRT from 2008 to 2017 were reviewed. Patients with metastases after CRT were included. Those with metastatic tumors at the initial diagnosis were excluded. @*Results@#Fourteen patients (1.3%) of 1,092 who received CRT presented with metastases. Magnetic resonance circumferential resection margin (mrCRM) and mesorectal lymph nodes (LNs) were positive in 12 patients (85.7%). Meanwhile, magnetic resonance extramural vascular invasion (mrEMVI) was positive in 10 patients (71.4%). Magnetic resonance tumor regression grade (mrTRG) 4 and mrTRG5 was detected in 5 and 1 patient respectively. Ten patients (71.4%) underwent combined surgery and 3 (21.4%) received palliative chemotherapy. @*Conclusion@#Patients with metastases after CRT showed a higher rate of positive mrCRM, mrEMVI, mesorectal LNs, and poor tumor response. Further studies with a large number of patients are necessary for better survival outcomes in LARC.
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Objective@#To compare the performance of the deep learning-based lesion detection algorithm (DLLD) in detecting liver metastasis with that of radiologists. @*Materials and Methods@#This clinical retrospective study used 4386-slice computed tomography (CT) images and labels from a training cohort (502 patients with colorectal cancer [CRC] from November 2005 to December 2010) to train the DLLD for detecting liver metastasis, and used CT images of a validation cohort (40 patients with 99 liver metastatic lesions and 45 patients without liver metastasis from January 2011 to December 2011) for comparing the performance of the DLLD with that of readers (three abdominal radiologists and three radiology residents). For per-lesion binary classification, the sensitivity and false positives per patient were measured. @*Results@#A total of 85 patients with CRC were included in the validation cohort. In the comparison based on per-lesion binary classification, the sensitivity of DLLD (81.82%, [81/99]) was comparable to that of abdominal radiologists (80.81%, p = 0.80) and radiology residents (79.46%, p = 0.57). However, the false positives per patient with DLLD (1.330) was higher than that of abdominal radiologists (0.357, p < 0.001) and radiology residents (0.667, p < 0.001). @*Conclusion@#DLLD showed a sensitivity comparable to that of radiologists when detecting liver metastasis in patients initially diagnosed with CRC. However, the false positives of DLLD were higher than those of radiologists. Therefore, DLLD could serve as an assistant tool for detecting liver metastasis instead of a standalone diagnostic tool.
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Purpose@#To assess associations between surveillance intervals in a national hepatocellular carcinoma (HCC) surveillance program and receiving curative treatment and mortality using nationwide cohort data for Korea. @*Materials and Methods@#Using the National Health Insurance Service Database of Korea, we retrospectively identified 3201852 patients, the target population of the national HCC surveillance program, between 2008 and 2017. After exclusion, a total of 64674 HCC patients were divided based on surveillance intervals: never screened, ≤6 months (6M), 7–12 months (1Y), 13–24 months (2Y), and 25–36 months (3Y). Associations for surveillance interval with the chance to receive curative therapy and all-cause mortality were analyzed. @*Results@#The 6M group (51.9%) received curative therapy more often than the other groups (1Y, 48.3%; 2Y, 43.8%; 3Y, 41.3%; never screened, 34.5%). Odds ratio for receiving curative therapy among the other surveillance interval groups (1Y, 0.87; 2Y, 0.76; 3Y, 0.77;never screened, 0.57; p<0.001) were significantly lower than that of the 6M group. The hazard ratios (HRs) of all-cause mortality were 1.07, 1.14, and 1.37 for 2Y, 3Y, and never screened groups. The HR for the 1Y group (0.96; p=0.092) was not significantly different, and it was lower (0.91; p<0.001) than that of the 6M group after adjustment for lead-time bias. Curative therapy was associated with survival benefits (HR, 0.26; p<0.001). @*Conclusion@#HCC surveillance, especially at a surveillance interval of 6 months, increases the chance to receive curative therapy.
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PURPOSE: This study aimed to develop a multi-channel near-infrared spectroscopy (NIRS) and ultrasonography (USG) fusion imaging system for imaging prostate cancer and to verify its diagnostic capability by applying the hybrid imaging system to a prostate cancer phantom. METHODS: A multi-channel NIRS system using the near-infrared 785-nm wavelength with 12 channels and four detectors was developed. After arranging the optical fibers around a USG transducer, we performed NIRS imaging and grayscale USG imaging simultaneously. Fusion imaging was obtained by processing incoming signals and the spatial reconstruction of NIRS, which corresponded with grayscale USG acquired at the same time. The NIRS-USG hybrid system was applied to a silicone-based optical phantom of the prostate gland containing prostate cancer to verify its diagnostic capability qualitatively. RESULTS: The NIRS-USG hybrid imaging system for prostate cancer imaging simultaneously provided anatomical and optical information with 2-dimensional registration. The hybrid imaging system showed more NIR attenuation over the prostate cancer model than over the model of normal prostate tissue. Its diagnostic capability to discriminate a focal area mimicking the optical properties of prostate cancer from the surrounding background mimicking the optical properties of normal prostate tissue was verified by applying the hybrid system to a silicone-based optical phantom of prostate cancer. CONCLUSION: This study successfully demonstrated that the NIRS-USG hybrid system may serve as a new imaging method for improving the diagnostic accuracy of prostate cancer, with potential utility for future clinical applications.
Subject(s)
Diagnosis , Methods , Optical Fibers , Prostate , Prostatic Neoplasms , Spectroscopy, Near-Infrared , Transducers , UltrasonographyABSTRACT
PURPOSE: Extraosseous Ewing's sarcoma (EOE) of the rectum is extremely rare: only three cases have been reported in the literature and none of these reports described their imaging findings in detail. Herein, we describe the tumor imaging and pathological features in detail. MATERIALS AND METHODS: We report a case of rectal EOE in a 72-year-old female who received local excision and was provisionally diagnosed with a rectal submucosal spindle cell tumor. We used immunohistochemistry, histopathology, and fluorescence in situ hybridization to characterize the tumor and provide a definitive diagnosis of EOE. RESULTS: MRI revealed a well-demarcated submucosal tumor with heterogeneous enhancement and hemorrhagic foci in rectum. EOE was diagnosed by positive staining of tumor cells for CD99 and Fli-1 by immunohistochemistry and the presence of the EWSR1 gene translocation by fluorescence in situ hybridization. Although the patient underwent radiation treatment and surgery, the tumor recurred after 4 months as revealed by computed tomography and magnetic resonance imaging. CONCLUSION: Rectal EOE may present as a rectal submucosal tumor. The understanding of imaging and histological characteristics of this tumor are critical for accurate diagnosis and appropriate aggressive treatment.