Interpretation of Complete Tumor Response on MRI Following Chemoradiotherapy of Rectal Cancer: Inter-Reader Agreement and Associated Factors in Multi-Center Clinical Practice

OBJECTIVE

To measure inter-reader agreement and identify associated factors in interpreting complete response (CR) on magnetic resonance imaging (MRI) following chemoradiotherapy (CRT) for rectal cancer.

MATERIALS AND METHODS

This retrospective study involved 10 readers from seven hospitals with experience of 80-10210 cases, and 149 patients who underwent surgery after CRT for rectal cancer. Using MRI-based tumor regression grading (mrTRG) and methods employed in daily practice, the readers independently assessed mrTRG, CR on T2-weighted images (T2WI) denoted as mrCRT2W, and CR on all images including diffusion-weighted images (DWI) denoted as mrCRoverall. The readers described their interpretation patterns and how they utilized DWI. Inter-reader agreement was measured using multi-rater kappa, and associated factors were analyzed using multivariable regression. Correlation between sensitivity and specificity of each reader was analyzed using Spearman coefficient.

RESULTS

The mrCRT2W and mrCRoverall rates varied widely among the readers, ranging 18.8%-40.3% and 18.1%-34.9%, respectively. Nine readers used DWI as a supplement sequence, which modified interpretations on T2WI in 2.7% of cases (36/1341 [149 patients × 9 readers]) and mostly (33/36) changed mrCRT2W to non-mrCRoverall. The kappa values for mrTRG, mrCRT2W, and mrCRoverall were 0.56 (95% confidence interval: 0.49, 0.62), 0.55 (0.52, 0.57), and 0.54 (0.51, 0.57), respectively. No use of rectal gel, larger initial tumor size, and higher initial cT stage exhibited significant association with a higher inter-reader agreement for assessing mrCRoverall (P ≤ 0.042). Strong negative correlations were observed between the sensitivity and specificity of individual readers (coefficient, -0.718 to -0.963; P ≤ 0.019).

CONCLUSION

Inter-reader agreement was moderate for assessing CR on post-CRT MRI. Readers' varying standards on MRI interpretation (i.e., threshold effect), along with the use of rectal gel, initial tumor size, and initial cT stage, were significant factors associated with inter-reader agreement.

Deep Learning-Accelerated Liver Diffusion-Weighted Imaging: Intraindividual Comparison and Additional Phantom Study of Free-Breathing and Respiratory-Triggering Acquisitions

OBJECTIVES

Deep learning-reconstructed diffusion-weighted imaging (DL-DWI) is an emerging promising time-efficient method for liver evaluation, but analyses regarding different motion compensation strategies are lacking. This study evaluated the qualitative and quantitative features, sensitivity for focal lesion detection, and scan time of free-breathing (FB) DL-DWI and respiratory-triggered (RT) DL-DWI compared with RT conventional DWI (C-DWI) in the liver and a phantom.

MATERIALS AND METHODS

Eighty-six patients indicated for liver MRI underwent RT C-DWI, FB DL-DWI, and RT DL-DWI with matching imaging parameters other than the parallel imaging factor and number of averages. Two abdominal radiologists independently assessed qualitative features (structural sharpness, image noise, artifacts, and overall image quality) using a 5-point scale. The signal-to-noise ratio (SNR) along with the apparent diffusion coefficient (ADC) value and its standard deviation (SD) were measured in the liver parenchyma and a dedicated diffusion phantom. For focal lesions, per-lesion sensitivity, conspicuity score, SNR, and ADC value were evaluated. Wilcoxon signed rank test and repeated-measures analysis of variance with post hoc test revealed the difference in DWI sequences.

RESULTS

Compared with RT C-DWI, the scan times for FB DL-DWI and RT DL-DWI were reduced by 61.5% and 23.9%, respectively, with statistically significant differences between all 3 pairs (all P 's < 0.001). Respiratory-triggered DL-DWI showed a significantly sharper liver margin, less image noise, and more minor cardiac motion artifact compared with RT C-DWI (all P 's < 0.001), whereas FB DL-DWI showed more blurred liver margins and poorer intrahepatic vessels demarcation than RT C-DWI. Both FB- and RT DL-DWI showed significantly higher SNRs than RT C-DWI in all liver segments (all P 's < 0.001). There was no significant difference in overall ADC values across DWI sequences in the patient or phantom, with the highest value recorded in the left liver dome by RT C-DWI. The overall SD was significantly lower with FB DL-DWI and RT DL-DWI than RT C-DWI (all P 's ≤ 0.003). Respiratory-triggered DL-DWI showed a similar per-lesion sensitivity (0.96; 95% confidence interval, 0.90-0.99) and conspicuity score to those of RT C-DWI and significantly higher SNR and contrast-to-noise ratio values ( P ≤ 0.006). The per-lesion sensitivity of FB DL-DWI (0.91; 95% confidence interval, 0.85-0.95) was significantly lower than that of RT C-DWI ( P = 0.001), with a significantly lower conspicuity score.

CONCLUSIONS

Compared with RT C-DWI, RT DL-DWI demonstrated superior SNR, comparable sensitivity for focal hepatic lesions, and reduced acquisition time, making it a suitable alternative to RT C-DWI. Despite FB DL-DWI's weakness in motion-related challenges, further refinement could potentiate FB DL-DWI in the context of abbreviated screening protocols, where time efficiency is a high priority.

Survival Prediction after Curative Resection of Pancreatic Ductal Adenocarcinoma by Imaging-Based Intratumoral Necrosis

We aimed to determine the histopathological characteristics and prognosis of curatively resected pancreatic ductal adenocarcinoma (PDAC) showing intratumoral necrosis on preoperative CT or MRI. This study consecutively included 102 patients who underwent upfront surgery with margin-negative resection from 2012 to 2020. All patients underwent both pancreatic CT and MRI within 1 month before surgery. Two radiologists independently assessed CT/MRI findings, including the presence of CT- and MRI-detected necrosis. Histopathological characteristics of PDACs according to CT or MRI detection of necrosis were evaluated. Disease-free survival (DFS) and overall survival (OS) were assessed by the Kaplan−Meier method and the Cox proportional hazards model. Among the 102 PDAC patients, 14 patients (13.7%) had CT-detected necrosis, and 16 patients (15.7%) had MRI-detected necrosis, of which 9 showed both CT- and MRI-detected necrosis. PDACs with CT- or MRI-detected necrosis demonstrated a significantly higher degree of histopathological necrosis than those without (p < 0.001). Multivariable analysis revealed that tumor size (hazard ratio [HR], 1.19; p = 0.040), tumor location (HR, 0.46; p = 0.009), and MRI-detected necrosis (HR, 2.64; p = 0.002) had independent associations with DFS. Only MRI-detected necrosis was significantly associated with OS (HR, 2.59; p = 0.004). Therefore, MRI-detected necrosis might be a potential imaging predictor of poor survival after curative resection of PDAC.

LI-RADS Treatment Response versus Modified RECIST for Diagnosing Viable Hepatocellular Carcinoma after Locoregional Therapy: A Systematic Review and Meta-Analysis of Comparative Studies

Purpose

To systematically compare the performance of liver imaging reporting and data system treatment response (LR-TR) with the modified Response Evaluation Criteria in Solid Tumors (mRECIST) for diagnosing viable hepatocellular carcinoma (HCC) treated with locoregional therapy (LRT).

Materials and Methods

Original studies of intra-individual comparisons between the diagnostic performance of LR-TR and mRECIST using dynamic contrast-enhanced CT or MRI were searched in MEDLINE and EMBASE, up to August 25, 2021. The reference standard for tumor viability was surgical pathology. The meta-analytic pooled sensitivity and specificity of the viable category using each criterion were calculated using a bivariate random-effects model and compared using bivariate meta-regression.

Results

For five eligible studies (430 patients with 631 treated observations), the pooled per-lesion sensitivities and specificities were 58% (95% confidence interval [CI], 45%–70%) and 93% (95% CI, 88%–96%) for the LR-TR viable category and 56% (95% CI, 42%–69%) and 86% (95% CI, 72%–94%) for the mRECIST viable category, respectively. The LR-TR viable category provided significantly higher pooled specificity (p < 0.01) than the mRECIST but comparable pooled sensitivity (p = 0.53).

Conclusion

The LR-TR algorithm demonstrated better specificity than mRECIST, without a significant difference in sensitivity for the diagnosis of pathologically viable HCC after LRT.

Usefulness of Arterial Subtraction in Applying Liver Imaging Reporting and Data System (LI-RADS) Treatment Response Algorithm to Gadoxetic Acid-Enhanced MRI

Objective

We aimed to evaluate the usefulness of arterial subtraction images for predicting the viability of hepatocellular carcinoma (HCC) after locoregional therapy (LRT) using gadoxetic acid-enhanced MRI and the Liver Imaging Reporting and Data System treatment response (LR-TR) algorithm.

Materials and Methods

This study included 90 patients (mean age ± standard deviation, 57 ± 9 years) who underwent liver transplantation or resection after LRT and had 73 viable and 32 nonviable HCCs. All patients underwent gadoxetic acid-enhanced MRI before surgery. Two radiologists assessed the presence of LR-TR features, including arterial phase hyperenhancement (APHE) and LR-TR categories (viable, nonviable, or equivocal), using ordinary arterial-phase and arterial subtraction images. The reference standard for tumor viability was surgical pathology. The sensitivity of APHE for diagnosing viable HCC was compared between ordinary arterial-phase and arterial subtraction images. The sensitivity and specificity of the LR-TR algorithm for diagnosing viable HCC was compared between the use of ordinary arterial-phase and the use of arterial subtraction images. Subgroup analysis was performed on lesions treated with transarterial chemoembolization (TACE) only.

Results

The sensitivity of APHE for viable HCCs was higher for arterial subtraction images than ordinary arterial-phase images (71.2% vs. 47.9%; p < 0.001). LR-TR viable category with the use of arterial subtraction images compared with ordinary arterial-phase images showed a significant increase in sensitivity (76.7% [56/73] vs. 63.0% [46/73]; p = 0.002) without significant decrease in specificity (90.6% [29/32] vs. 93.8% [30/32]; p > 0.999). In a subgroup of 63 lesions treated with TACE only, the use of arterial subtraction images showed a significant increase in sensitivity (81.4% [35/43] vs. 67.4% [29/43]; p = 0.031) without significant decrease in specificity (85.0% [17/20] vs. 90.0% [18/20]; p > 0.999).

Conclusion

Use of arterial subtraction images compared with ordinary arterial-phase images improved the sensitivity while maintaining specificity for diagnosing viable HCC after LRT using gadoxetic acid-enhanced MRI and the LR-TR algorithm.

Diagnostic performance of Liver Imaging Reporting and Data System treatment response algorithm: a systematic review and meta-analysis

OBJECTIVE

To systematically determine the accuracy of Liver Imaging Reporting and Data System treatment response (LR-TR) algorithm for diagnosing the viability of hepatocellular carcinoma (HCC) treated with locoregional therapy (LRT).

METHODS

Original studies reporting the diagnostic accuracy of LR-TR algorithm on dynamic contrast-enhanced computed tomography or magnetic resonance imaging (MRI) were identified in MEDLINE and EMBASE up to June 1, 2020. The meta-analytic summary sensitivity and specificity of LR-TR algorithm were calculated using a bivariate random-effects model. Subgroup analyses and meta-regression analysis were performed to explore study heterogeneity.

RESULTS

We found six studies reporting the accuracy of LR-TR viable category (601 observations in 453 patients). The meta-analytic pooled sensitivity and specificity of LR-TR viable category were 63% (95% confidence interval [CI], 39-81%; I² = 88%) and 96% (95% CI, 91-99%; I² = 76%), respectively. The meta-analytic pooled sensitivity and specificity of LR-TR viable or equivocal category combined were 71% (95% CI, 55-84%; I² = 89%) and 87% (95% CI, 73-94% I² = 80%), respectively. Studies which used only MRI showed a trend towards higher sensitivity (71% [95% CI, 46-88%]) with a comparable specificity (95% [95% CI, 86-99%]) of LR-TR viable category compared to the whole group. The type of reference standard and study design were significantly associated with study heterogeneity (p ≤ 0.01).

CONCLUSIONS

The LR-TR viable category had high specificity but suboptimal sensitivity for diagnosing the viability of HCC after LRT. Substantial study heterogeneity was noted, and it was significantly associated with the type of reference standard and study design.

KEY POINTS

• The meta-analytic pooled sensitivity and specificity of LR-TR viable category were 63% (95% CI, 39-81%) and 96% (95% CI, 91-99%), respectively. • The meta-analytic pooled sensitivity and specificity of LR-TR viable or equivocal category combined were 71% (95% CI, 55-84%) and 87% (95% CI, 73-94%), respectively. • The type of reference standard and study design were the factors significantly influencing study heterogeneity (p ≤ 0.01).

Immunoglobulin G4-related Disease of the Genitourinary System: Spectrum of Imaging Findings and Clinical-Pathologic Features

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterized by focal or diffuse organ infiltration of IgG4-bearing plasma cells. The diagnosis of IgG4-RD is based on a combination of clinical, serologic, radiologic, and histopathologic findings. IgG4-RD has been reported to affect almost all organ systems. The kidney is the most frequently involved of the genitourinary organs. The most common renal manifestation of IgG4-RD is IgG4-RD tubulointerstitial nephritis, followed by membranous glomerulonephropathy and, less frequently, obstructive nephropathy involving the renal pelvis, ureter, or retroperitoneum. Renal parenchymal lesions may appear as multiple nodular lesions, diffuse patchy infiltrative lesions, or a single nodular lesion. Multiple small nodular cortical lesions are the most common imaging findings of IgG4-RD involving the kidney. Renal pelvic, sinus, or perinephric lesions can also occur. IgG4-RD involvement of other genitourinary organs including the ureter, bladder, urethra, and male and female reproductive organs is rare compared with kidney involvement but may show variable imaging findings such as a localized mass within or surrounding the involved organ or diffuse enlargement of the involved organ. Imaging findings of IgG4-RD involving the genitourinary system are nonspecific but should be differentiated from inflammatory and neoplastic lesions that mimic IgG4-RD. The online slide presentation from the RSNA Annual Meeting is available for this article. ^©RSNA, 2020.

Prognostic role of pre-sarcopenia and body composition with long-term outcomes in obstructive colorectal cancer: a retrospective cohort study

Background

The clinical significance of pre-sarcopenia in colorectal cancer obstruction has not yet been described. The present study aimed to determine the short- and long-term oncologic impacts of pre-sarcopenia in obstructive colorectal cancer.

Methods

We retrospectively analyzed 214 patients with obstructive colon cancer between January 2004 and December 2013. Initial staging computed tomography (CT) scans identified pre-sarcopenia and visceral obesity by measuring the muscle and visceral fat areas at the third lumbar vertebra level. Both short-term postoperative and long-term oncologic outcomes were analyzed.

Results

Among all 214 patients, 71 (33.2%) were diagnosed with pre-sarcopenia. Pre-sarcopenia had a negative oncologic impact in both disease-free survival (DFS) and overall survival (OS), (hazard ratio [HR] = 1.86, 95% confidence interval [CI] 1.04–3.13, p = 0.037, and HR = 1.92, CI 1.02–3.60, p = 0.043, respectively). Visceral adiposity, body mass index (BMI), and neutrophil-lymphocyte ratio (NLR) did not significantly impact DFS and OS.

Conclusion

Pre-sarcopenia is a clinical factor significantly associated with OS and DFS but not with short-term complications in obstructive colorectal cancer. In future, prospective studies should incorporate body composition data in patient risk assessments and oncologic prediction tools.

Reproducibility of mRECIST in Measurement and Response Assessment for Hepatocellular Carcinoma Treated by Transarterial Chemoembolization

RATIONALE AND OBJECTIVES

To evaluate the reproducibility of Modified Response Evaluation Criteria in Solid Tumors (mRECIST) for hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE) using multiphasic computed tomography.

MATERIALS AND METHODS

The institutional review board approved this retrospective study. We evaluated 97 patients who underwent TACE (60 conventional TACE [cTACE] and 37 drug-eluting bead TACE [DEB-TACE]) for HCC from 2010 to 2014. Four radiologists evaluated pairs of dynamic liver CTs scanned within 2 months before and after TACE based on mRECIST. Assessment of intra- or interobserver reproducibility for response categorization and sum of long diameter were evaluated using weighted kappa statistics (κ) and intraclass correlation coefficients, respectively. The relationship between concordance of target lesion selection and agreement of target lesion response was evaluated using Fisher exact test.

RESULTS

Intraobserver reproducibility for overall response was moderate to excellent (κ = 0.525-0.865). Interobserver reproducibility was improved on the second review compared to the first review and it was good in both treatment groups (κ = 0.627 for cTACE and 0.602 for DEB-TACE). Between the two treatment methods, intra- or interobserver reproducibility was better after cTACE than DEB-TACE. Intraclass correlation coefficients for sum of long diameter measurement showed excellent intra- or interobserver reproducibility. The concordance rate of target lesion selection was significantly higher for patients with radiologists' agreement for target lesion response than patients with disagreed response (P = .003).

CONCLUSIONS

The intra- and interobserver reproducibility of mRECIST in patients with HCC after TACE was moderate to excellent, and the reproducibility was slightly better after cTACE than DEB-TACE.

Sarcopenia is negatively associated with long-term outcomes in locally advanced rectal cancer

BACKGROUND

The association of sarcopenia and visceral obesity to treatment outcome is not clear for locally advanced rectal cancer. This study evaluates the influence of skeletal muscle and visceral fat on short-term and long-term outcomes in locally advanced rectal cancer patients treated with neoadjuvant chemoradiation therapy followed by curative resection.

METHODS

A total of 188 patients with locally advanced cancer were included between January 2009 and December 2013. Neoadjuvant chemoradiotherapy was followed by curative resection. Sarcopenia and visceral obesity were identified in initial staging CT by measuring the muscle and visceral fat area at the third lumbar vertebra level.

RESULTS

Among the 188 included patients, 74 (39.4%) patients were sarcopenic and 97 (51.6%) patients were viscerally obese. Sarcopenia and high levels of preoperative carcinoembryonic antigen were significant prognostic factors for overall survival (P = 0.013, 0.014, respectively) in the Cox regression multivariate analysis. Visceral obesity was not associated with overall survival; however, it did tend to shorten disease-free survival (P = 0.079).

CONCLUSIONS

Sarcopenia is negatively associated with overall survival in locally advanced rectal cancer patients who underwent neoadjuvant chemoradiation therapy and curative resection. Visceral obesity tended to shorten disease-free survival. Future studies should be directed to optimize patient conditions according to body composition status.

Educational Effects of Radiation Reduction During Fluoroscopic Examination of the Adult Gastrointestinal Tract

RATIONALE AND OBJECTIVES

This study aimed to evaluate the effects of educating radiology residents and radiographers about radiation exposure on reduction of dose area product (DAP) and fluoroscopy time in diagnostic fluoroscopy of the gastrointestinal (GI) tract in adult patients.

MATERIALS AND METHODS

In April 2015, we offered 1 hour of education to radiology residents and radiographers on how to reduce radiation doses during fluoroscopic examinations. Fluoroscopic examinations of the GI tracts of adult patients performed from June 2014 to February 2016 were evaluated. A total of 2326 fluoroscopic examinations (779 and 1547 examinations before and after education, respectively) were performed, including 10 kinds of examinations. Fluoroscopy time and DAP were collected. A radiologist evaluated the number of spot images, captured images, cine video, captured video, and the use of collimation or magnification. We used the Mann-Whitney U test to assess the difference in fluoroscopy-related factors before and after education.

RESULTS

Median DAP decreased significantly after education, from 21.1 to 18.2 Gy∙cm² (P < .001) in all examinations. After education DAP decreased significantly in defecography (P < .001) and fluoroscopy time decreased significantly in upper gastrointestinal series with water-soluble contrast (P < .001). Spot and cine images that increased the radiation dose were used less frequently after education than before in some kinds of examinations, especially in defecography (P < .001). More images were collimated after education in barium swallow than before (P < .001).

CONCLUSIONS

Educating radiologist residents and radiographers could reduce DAP in fluoroscopy examinations of the GI tract in adult patients.

USPIO enhanced lymph node MRI using 3D multi-echo GRE in a rabbit model

Ultrasmallsuperparamagnetic iron oxide (USPIO) has been suggested to be a negative MR contrast agent to detect metastatic lymph nodes. Previously reported studies have evaluated the diagnostic performance of USPIO-enhanced MR lymph node imaging based on signal intensity. In this study, we investigate the specific performance of three different parametric approaches (normalized signal intensity, R₂ * and susceptibility) using 3D multi-echo gradient echo to quantify the USPIO particles in lymph nodes. Nine rabbits with VX2 tumor implants were scanned before and after USPIO injection. From 3D multi-echo GRE magnitude and phase data, we generated multi-echo combined T₂ *-weighted images, an R₂ * map, and a quantitative susceptibility map. Eighteen lymph nodes (nine reactive and nine metastatic) were evaluated and showed remarkable signal drops in the area of USPIO accumulation. On parametric analysis, the R₂ * difference before and after USPIO injection was significantly different (p < 0.05) between reactive and metastatic lymph nodes; in contrast, the normalized signal intensity and susceptibility were not significantly different between the nodes. Our study showed the potential utility of USPIO-enhanced MRI using R2* mapping from 3D multi-echo GRE for the detection of lymph node metastasis and parametric analysis of lymph node status in a rabbit model. Copyright © 2016 John Wiley & Sons, Ltd.

Diffusion-weighted imaging: Apparent diffusion coefficient histogram analysis for detecting pathologic complete response to chemoradiotherapy in locally advanced rectal cancer

PURPOSE

To investigate the usefulness of apparent diffusion coefficient (ADC) values derived from histogram analysis of the whole rectal cancer as a quantitative parameter to evaluate pathologic complete response (pCR) on preoperative magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We enrolled a total of 86 consecutive patients who had undergone surgery for rectal cancer after neoadjuvant chemoradiotherapy (CRT) at our institution between July 2012 and November 2014. Two radiologists who were blinded to the final pathological results reviewed post-CRT MRI to evaluate tumor stage. Quantitative image analysis was performed using T2 -weighted and diffusion-weighted images independently by two radiologists using dedicated software that performed histogram analysis to assess the distribution of ADC in the whole tumor.

RESULTS

After surgery, 16 patients were confirmed to have achieved pCR (18.6%). All parameters from pre- and post-CRT ADC histogram showed good or excellent agreement between two readers. The minimum, 10th, 25th, 50th, and 75th percentile and mean ADC from post-CRT ADC histogram were significantly higher in the pCR group than in the non-pCR group for both readers. The 25th percentile value from ADC histogram in post-CRT MRI had the best diagnostic performance for detecting pCR, with an area under the receiver operating characteristic curve of 0.796.

CONCLUSION

Low percentile values derived from the ADC histogram analysis of rectal cancer on MRI after CRT showed a significant difference between pCR and non-pCR groups, demonstrating the utility of the ADC value as a quantitative and objective marker to evaluate complete pathologic response to preoperative CRT in rectal cancer. J. Magn. Reson. Imaging 2016;44:212-220.

Ultrasonographic findings of low-grade endometrial stromal sarcoma of the uterus with a focus on cystic degeneration

PURPOSE

The goal of this study was to perform a retrospective analysis of the ultrasonographic findings associated with low-grade endometrial stromal sarcoma.

METHODS

Ten pathologically confirmed cases of low-grade endometrial stromal sarcoma at our institution from January 2007 to April 2014 were retrospectively reviewed. All patients underwent a preoperative transvaginal ultrasound. Two radiologists came to a consensus regarding the location, size, margin, and echogenicity of the tumor, as well as the presence of intratumoral cystic degeneration and its extent and configuration.

RESULTS

Low-grade endometrial stromal sarcoma manifested as an intramural mass protruding into the endometrial cavity (n=6) or as a purely intramural mass (n=4). The maximal diameter of the lesion ranged from 4 to 9.1 cm (mean, 6.2 cm). The imaging features of low-grade endometrial stromal sarcoma were variable: six cases involved predominantly solid masses containing cystic degeneration, one was a predominantly unilocular cystic mass, two were ill-defined infiltrative solid masses, and one was a well-defined solid mass. Among the seven cases with internal cystic degeneration, five patients showed a multiseptated cystic area or a cystic area with multiple small clusters, while a unilocular cystic area within the tumor was found in two patients.

CONCLUSION

Low-grade endometrial stromal sarcoma is associated with variable ultrasonographic findings with regard to the location, margin, and configuration of the lesion. Multiseptated cystic areas and multiple small areas of cystic degeneration are common.

Diffusion-weighted MRI of epithelial ovarian cancers: correlation of apparent diffusion coefficient values with histologic grade and surgical stage

OBJECTIVE

The purpose of this article is to correlate the apparent diffusion coefficient (ADC) values of epithelial ovarian cancers with histologic grade and surgical stage.

MATERIALS AND METHODS

We enrolled 43 patients with pathologically proven epithelial ovarian cancers for this retrospective study. All patients underwent preoperative pelvic magnetic resonance imaging (MRI) including diffusion-weighted images with b value of 0 and 1000 s/mm2 at 3.0-T unit. The mean ADC values of the solid portion of the tumor were measured and compared among different histologic grades and surgical stages.

RESULTS

The mean ADC values of epithelial ovarian cancers differed significantly between grade 1 (well-differentiated) and grade 2 (moderately-differentiated) (P=0.013) as well as between grade 1 and grade 3 (poorly-differentiated) (P=0.01); however, no statistically significant difference existed between grade 2 and grade 3 (P=0.737). The receiver-operating characteristic analysis indicated that a cutoff ADC value of less than or equal to 1.09×10(-3)mm2/s was associated with 94.4% sensitivity and 85.7% specificity in distinguishing grade 1 and grade 2/3 cancer. The difference in mean ADC values was statistically significant for early stage (FIGO stage I) and advanced stage (FIGO stage II-IV) cancer (P=0.011). The interobserver agreement for the mean ADC values of epithelial ovarian cancers was excellent.

CONCLUSION

The mean ADC values of the solid portion of epithelial ovarian cancers negatively correlated to histologic grade and surgical stage. The mean ADC values may be useful imaging biomarkers for assessment of tumor grade of epithelial ovarian cancer.

Computed tomography and magnetic resonance imaging evaluation of lymph node metastasis in early colorectal cancer

AIM: To assess the role of computed tomography (CT) and magnetic resonance imaging (MRI) and establish imaging criteria of lymph node metastasis in early colorectal cancer.

METHODS: One hundred and sixty patients with early colorectal cancer were evaluated for tumor location, clinical history of polypectomy, depth of tumor invasion, and lymph node metastasis. Two radiologists assessed preoperative CT and/or MRI for the primary tumor site detectability, the presence or absence of regional lymph node, and the size of the largest lymph node. Demographic, imaging, and pathologic findings were compared between the two groups of patients based on pathologic lymph node metastasis and optimal size criterion was obtained.

RESULTS: The locations of tumor were ascending, transverse, descending, sigmoid colon, and rectum. One hundred and sixty early colorectal cancers were classified into 3 groups based on the pathological depth of tumor invasion; mucosa, submucosa, and depth unavailable. A total of 20 (12.5%) cancers with submucosal invasion showed lymph node metastasis. Lymph nodes were detected on CT or MRI in 53 patients. The detection rate and size of lymph nodes were significantly higher (P = 0.000, P = 0.044, respectively) in patients with pathologic nodal metastasis than in patients without nodal metastasis. Receiver operating curve analysis showed that a cut-off value of 4.1 mm is optimal with a sensitivity of 78.6% and specificity of 75%.

CONCLUSION: The short diameter size criterion of ≥ 4.1 mm for metastatic lymph nodes was optimal for nodal staging in early colorectal cancer.

Alveolar soft part sarcoma arising from the kidney: imaging and clinical features

Alveolar soft part sarcoma (ASPS) is an extremely rare malignant soft tissue sarcoma primarily affecting young patients. It usually occurs in the lower extremities, although it can occur in soft tissue anywhere in the body. However, to our knowledge, there has been no case of primary ASPS originating from the kidney in the literature. We herein present the imaging and clinical features of an ASPS which occurred in a 16-year-old male presented as a palpable mass in the left side of the abdomen.

Intra- and interobserver reliability of gray scale/dynamic range evaluation of ultrasonography using a standardized phantom

PURPOSE

To evaluate intra- and interobserver reliability of the gray scale/dynamic range of the phantom image evaluation of ultrasonography using a standardized phantom, and to assess the effect of interactive education on the reliability.

METHODS

Three radiologists (a resident, and two board-certified radiologists with 2 and 7 years of experience in evaluating ultrasound phantom images) performed the gray scale/dynamic range test for an ultrasound machine using a standardized phantom. They scored the number of visible cylindrical structures of varying degrees of brightness and made a 'pass or fail' decision. First, they scored 49 phantom images twice from a 2010 survey with limited knowledge of phantom images. After this, the radiologists underwent two hours of interactive education for the phantom images and scored another 91 phantom images from a 2011 survey twice. Intra- and interobserver reliability before and after the interactive education session were analyzed using K analyses.

RESULTS

Before education, the K-value for intraobserver reliability for the radiologist with 7 years of experience, 2 years of experience, and the resident was 0.386, 0.469, and 0.465, respectively. After education, the K-values were improved (0.823, 0.611, and 0.711, respectively). For interobserver reliability, the K-value was also better after the education for the 3 participants (0.067, 0.002, and 0.547 before education; 0.635, 0.667, and 0.616 after education, respectively).

CONCLUSION

The intra- and interobserver reliability of the gray scale/dynamic range was fair to substantial. Interactive education can improve reliability. For more reliable results, double- checking of phantom images by multiple reviewers is recommended.

Correlation of dynamic contrast-enhanced MRI perfusion parameters with angiogenesis and biologic aggressiveness of rectal cancer: Preliminary results

PURPOSE

To investigate whether quantitative parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) are correlated with angiogenesis and biologic aggressiveness of rectal cancer.

MATERIALS AND METHODS

A total of 46 patients with rectal cancer underwent DCE-MRI. Using a two-compartmental model, quantitative parameters (K(trans) , kep , ve , and iAUC) were calculated from the whole-transverse region of interest (ROI) and high K(trans) area ROI of entire tumors. Histological specimens were analyzed for tumor size; T/N stage; lymphatic, vascular, perineural invasion; expression of epidermal growth factor receptor (EGFR); and KRAS gene mutations. Tumor angiogenesis was evaluated based on the microvessel density (MVD) and the expression level of the vascular endothelial growth factor. Correlations of the DCE-MRI parameters with histological markers and angiogenesis were determined using Student's t-test and analysis of variance (ANOVA).

RESULTS

The mean kep from high K(trans) area ROIs showed a significantly positive correlation with MVD (P  =  0.030, r  =  0.514, R(2)   =  0.264). The mean kep from the whole-transverse ROIs showed a significant inverse correlation with T stage (T1 vs. T2-4, P  =  0.021). EGFR-positive cancer displayed higher mean K(trans) (P  =  0.045) and kep (P  =  0.038) than EGFR-negative cancer in whole-transverse ROIs.

CONCLUSION

These preliminary results suggest that the determination of kep of high K(trans) area permits the noninvasive estimation of tumor angiogenesis in rectal cancer and that DCE-MRI parameters can be used as imaging biomarkers to predict the biologic aggressiveness of the tumor and patient prognosis.

A feasibility study of unidirectional 240°-angle 3D CT colonography

In three-dimensional (3D) CT colonography (CTC), a wider viewing angle provides a larger field of view. The purpose of this study was to investigate the polyp detection rate and time efficiency of unidirectional 240°-angle 3D CTC compared with bidirectional 120°-angle CTC. CTC data sets of 40 patients were reviewed by two readers using the two methods. The unidirectional 240°-angle CTC showed a performance in polyp detection similar to the bidirectional 120°-angle CTC with improved time efficiency.

Comparison of bolus transit patterns identified by esophageal impedance to barium esophagram in patients with dysphagia

Bolus transit through the esophagus has not been validated by videoesophagram in patients with dysphagia and changes in impedance with abnormal barium transit have not been described in those patients. The aim of this study was to compare esophageal impedance findings with barium esophagram measurements in patients with dysphagia. The consecutive patients with dysphagia underwent conventional multichannel esophageal impedance manometry, after which a barium videoesophagram was performed simultaneously with multichannel esophageal impedance manometry using a mean of three swallows of barium. Esophageal emptying patterns shown in the esophagogram were classified by the degree of intraesophageal stasis and presence of intraesophageal reflux. Bolus transit patterns in impedance were classified as complete and incomplete transit. Sixteen patients (M : F = 8 : 8, mean age, 47 years) were enrolled. Their manometric diagnosis were normal (n= 6), ineffective esophageal motility (n= 1), diffuse esophageal spasm (DES; n= 2), and achalasia (n= 7). Sixty-three swallows were analyzed. According to impedance analysis, 21/22 swallows with normal barium emptying showed complete transit (96%) and 31/32 swallows with severe stasis showed incomplete transit (97%). Nine swallows with mild stasis showed either complete or incomplete transit patterns in impedance. Swallows with mild barium stasis and complete transit in impedance were observed in patients who had received treatment (two patients with achalasia with history of esophageal balloonplasty and a patient with DES after nifedipine administration). Impedance reflected severe stasis with retrograde barium movement and described typical bolus transit patterns in patients with achalasia and DES. In conclusion, impedance-barium esophagram concordance is high for swallows with normal esophageal emptying and for severe barium stasis in patients with dysphagia.

Fraudulent retouching of digital radiographic images--a potential risk

AIM

To determine whether radiologists can recognize images retouched to include sham lesions.

MATERIALS AND METHODS

Ten representative key images were selected of aortic dissection, hepatocellular carcinoma, renal cell carcinoma, colon cancer, liver metastasis, hepatic cyst, gallbladder stones, splenic artery aneurysm, adrenal adenoma, and stomach cancer from abdominal computed tomography (CT) imaging performed in 2008. Five of the key images were replaced with retouched images using image-editing software. The time to complete retouching was recorded for each image. Radiologists were requested to make a diagnosis for the 10 images, and were then asked to identify possible retouched images. The time taken to reach a decision in each case was recorded. Thirty radiologists (13 residents and 17 attending radiologists) participated as reviewers.

RESULTS

The time to complete retouching was 15.2±3.15 min. None of the reviewers recognized that some images were retouched during diagnosis. The rate of correct diagnosis was 90% (range 71.7-100%). After reviewers were informed of possible image retouching, the detection rate of retouched images was 50% (40-58.3%). This rate was statistically the same as random choice (p=0.876). There was no significant difference between residents and attending radiologists in the detection rate of retouched images (p=0.786). The time to diagnosis and the time to detection of the retouched images were 15 (14-17) and 6 (5-7) min, respectively.

CONCLUSION

Digital images can be easily retouched, and radiologists have difficulty in identifying retouched images. Radiologists should be aware of the potential fraudulent use of retouched images.

Imaging findings of intrahepatic bile duct adenoma (peribiliary gland hamartoma): a case report and literature review

Intrahepatic bile duct adenoma is a rare benign epithelial hepatic tumor derived from bile duct cells. We report the imaging findings of a patient with bile duct adenoma, which appeared as a small heterogeneously enhancing mass with focal small cystic change on CT and MRI. Follow-up images at seven months showed a slight increase in tumor size, which could be partly explained by intratumoral hemorrhage on pathologic examination. Although rare, bile duct adenoma should be considered as a differential diagnosis of a small hypervascular tumor located in the periphery of liver. Focal cystic change and intratumoral hemorrhage may occur.

Lupus mesenteric vasculitis can cause acute abdominal pain in patients with SLE

Lupus mesenteric vasculitis (LMV) is a unique clinical entity found in patients who present with gastrointestinal manifestations of systemic lupus erythematosus, and is the main cause of acute abdominal pain in these patients. LMV usually presents as acute abdominal pain with sudden onset, severe intensity and diffuse localization. Other causes of abdominal pain, such as acute gastroenteritis, peptic ulcers, acute pancreatitis, peritonitis, and other reasons for abdominal surgery should be ruled out. Prompt and accurate diagnosis of LMV is critical to ensure implementation of appropriate immunosuppressive therapy and avoidance of unnecessary surgical intervention. The pathology of LMV comprises immune-complex deposition and complement activation, with subsequent submucosal edema, leukocytoclastic vasculitis and thrombus formation; most of these changes are confined to small mesenteric vessels. Abdominal CT is the most useful tool for diagnosing LMV, which is characterized by the presence of target signs, comb signs, and other associated findings. The presence of autoantibodies against phospholipids and endothelial cells might provide information about the likelihood of recurrence of LMV. Immediate, high-dose, intravenous steroid therapy can lead to a favorable outcome and prevent serious complications such as bowel ischemia, necrosis and perforation.

Case report. Lipomatous haemangiopericytoma (fat-forming solitary fibrous tumour) involving the perineum: CT and MRI findings and pathological correlation

Lipomatous haemangiopericytoma (a fat-forming solitary fibrous tumour) is a rare soft-tissue tumour histologically characterized by haemangiopericytomatous vasculature and the presence of mature adipocytes. We report the CT and MRI findings of a case of lipomatous haemangiopericytoma involving the perineum. CT showed a well-circumscribed soft-tissue density mass containing a small area of fat density and a punctuate calcification. On MR images, the mass was mostly isointense to the muscle on T(1) weighted images, with heterogeneous signal intensity on T(2) weighted images, and showed strong contrast enhancement except for the fatty and dense collagenous components. This is the first case report of imaging findings of a lipomatous haemangiopericytoma in the radiological literature. Although rare, lipomatous haemangiopericytoma should be considered as a differential diagnosis of fat-containing, hypervascular soft-tissue tumours with variable signal intensity on T(2) weighted images.

Case report: Ovarian cavernous haemangioma presenting as a heavily calcified adnexal mass

Haemangioma is an extremely rare tumour of the ovary. We describe the CT and MRI findings of a heavily calcified ovarian haemangioma in a 69-year-old woman presenting with adnexal torsion. CT showed a well-circumscribed mass with extensive punctate calcifications, located posterior to the uterus. MR images showed dark signal intensities of the mass on both T(1) and T(2) weighted images, with poor enhancement of the mass on contrast-enhanced T(1) weighted images. MR images also demonstrated a beak-like protrusion from the adnexal mass, representing the adnexal torsion. This is the first case report of a heavily calcified ovarian haemangioma in the English literature. Although rare, ovarian haemangioma should be included in the differential diagnosis of a heavily calcified adnexal mass.

Primary signet ring cell carcinoma of the appendix: A rare case report and our 18-year experience

Primary adenocarcinoma of the appendix is a rare malignancy that constitutes < 0.5% of all gastrointestinal neoplasms. Moreover, primary signet ring cell carcinoma of the appendix is an exceedingly rare entity. We have encountered 15 cases of primary appendiceal cancer among 3389 patients who underwent appendectomy over the past 18 years. In the present report, we describe a rare case of primary signet ring cell carcinoma of the appendix with ovarian metastases and unresectable peritoneal dissemination occurring in a 67-year-old female patient. She underwent appendectomy and bilateral salpingo-oophorectomy with a laparoscopy procedure. She then received palliative systemic chemotherapy with 12 cycles of oxaliplatin, 5-fluorouracil, and leucovorin (FOLFOX-4). The patient currently is well without progression of disease 12 mo after beginning chemotherapy.

Renal trauma

Urinary tract injury occurs in 10% of all abdominal trauma patients, and the kidney is the most commonly injured organ in the urinary tract. CT with contrast enhancement is the modality of choice for cross-sectional imaging of renal trauma because it quickly and accurately can demonstrate injury to the renal parenchyma, renal pedicles, and associated abdominal or retroperitoneal organs. This article reviews the mechanism, clinical features, imaging modalities, and CT imaging findings according to the classification of the renal trauma. Trauma to underlying abnormal kidneys, iatrogenic renal injuries, and complications of renal trauma are reviewed also.

Sonography of various cystic masses of the female groin

OBJECTIVE

The purpose of this presentation is to review the pathologic spectrum of cystic masses that may involve the female groin region, with a correlation of the lesions with their sonographic appearance.

METHODS

We reviewed the sonographic findings of palpable groin masses showing a cystic pattern in female patients. The groin region is best depicted with a high-frequency (7.5- to 12-MHz) linear array transducer. Color Doppler sonography and an extended field of view are helpful in the differential diagnosis of variable groin masses.

RESULTS

There are various cystic masses involving the female groin, such as round ligament cysts, varicosities of the round ligament, inguinal herniation of the ovary, cystic lymphangiomas, epidermal inclusion cysts, abscesses, and pseudoaneurysms.

CONCLUSIONS

Sonography with color Doppler imaging is helpful for the differential diagnosis of the pathologic spectrum of cystic masses involving the female groin.

Recurrent ovarian granulosa cell tumors: clinical and imaging features

BACKGROUND

Granulosa cell tumor of the ovary differs from epithelial ovarian tumors in histologic appearance, clinical course and imaging findings. The purpose of this study was to evaluate clinical and imaging features of recurrent ovarian granulosa cell tumors.

METHODS

We performed retrospective evaluation of the medical, surgicopathologic records and CT or MR images of 11 patients with pathologically proven recurrent ovarian granulosa cell tumor.

RESULTS

The first recurrence of granulosa cell tumor was diagnosed at between 4 months and 18 years after the initial surgical resection of tumor (mean; 9.7 years). Six patients relapsed after 10 years after initial diagnosis. The recurrent tumors were located in the pelvic cavity alone in three patients, extrapelvic peritoneal cavity alone in two, both pelvic and extrapelvic peritoneal cavity in three, and paraaortic retroperitoneal space in three. The imaging appearances of recurrent masses were variable ranging from solid masses to completely cystic masses.

CONCLUSION

Recurrent granulosa cell tumor is characterized by late tumor recurrence manifested as a relatively small number of discrete peritoneal or retroperitoneal masses with variable imaging appearances from solid to cystic masses.

Sonographic diagnosis of a round ligament cyst in the inguinal area

We report a case of a 37-year-old female with a mesothelial cyst of the round ligament presenting as a palpable mass. The mass appeared sonographically as a fusiform structure with several cystic anechoic areas and was misdiagnosed preoperatively as herniation of the right ovary.

Chilaiditi syndrome caused by Fitz-Hugh-Curtis syndrome: multidetector CT findings

Chilaiditi syndrome is a condition in which the colon or small intestine is interposed temporarily or permanently between the liver and the diaphragm. Usually, it is an asymptomatic and incidental radiographic finding, but it may be a potential source of abdominal problems, ranging from intermittent mild abdominal pain to acute intestinal obstruction. We report multidetector computed tomographic findings of a case of Chilaiditi syndrome presenting as small bowel obstruction due to hepatodiaphragmatic interposition of the ileal loop, which was entrapped by adhesive bands caused by Fitz-Hugh-Curtis syndrome.

The renal sinus: pathologic spectrum and multimodality imaging approach

Various pathologic conditions can occur in the renal sinus, primarily originating in the constituents of the renal sinus, and the renal sinus can be secondarily involved by surrounding renal parenchymal and adjacent retroperitoneal lesions. Lipomatosis and cysts are common renal sinus lesions with little clinical significance, but differentiation from other pathologic conditions is important. Renal vascular lesions such as renal artery aneurysm or arteriovenous fistula can mimic other parapelvic or peripelvic lesions at excretory urography, but their vascular nature is evident at color Doppler ultrasonography, contrast material-enhanced computed tomography (CT), and magnetic resonance (MR) imaging. Although most tumors originating in the renal pelvis are transitional cell carcinoma or squamous cell carcinoma, renal parenchymal tumors such as renal cell carcinoma or benign multilocular cystic nephroma have a tendency to grow into the renal sinus. Rare tumors of mesenchymal origin can develop in the renal sinus, but their imaging findings are nonspecific. The observation of renal sinus fat is important for detecting a small tumor located in that area and determining the exact tumor stage. Multiplanar CT or MR images can allow exact evaluation of the extent of complex renal sinus disease.

CT and MRI Findings of Sex Cord–Stromal Tumor of the Ovary

OBJECTIVE

The purpose of this article was to research the clinical and imaging features of sex cord-stromal tumors of the ovary to help in specific diagnosis of ovarian tumors. Sex cord-stromal tumors of the ovary are rare ovarian neoplasms, which arise from stromal cells and primitive sex cords in the ovary. The common types are granulosa cell tumors, fibrothecomas, sclerosing stromal tumors, and Sertoli-Leydig cell tumors. They account for most of the hormonally active ovarian tumors. They have characteristic imaging features in each type of the tumor.

CONCLUSION

Clinical and radiologic clues are helpful in differential diagnosis from the more common epithelial tumors; sex cord-stromal tumors primarily are treated surgically and have generally good prognosis.

Osteonecrosis in patients with systemic lupus erythematosus

This study was to describe the findings of osteonecrosis in patients with SLE at MR and scintigraphic imaging. Among 415 patients with SLE, 37 patients were diagnosed to have osteonecrosis. MR images and bone scintigraphs were analyzed for sites of involvement, signal intensity, bilaterality and multiplicity. MR imaging features of osteonecrosis in patients with SLE included isointense signal intensity relative to adjacent bone marrow, hypointense rim, marginal enhancement and unusual involvement of flat bones. Bilateral and multiple involvements were common.

Surface measurements of global warming causing atmospheric constituents in Korea

The expansion of the industrial economy and the increase of population in Northeast Asian countries have caused much interest in climate monitoring related to global warming. However, new techniques and better platforms for the measurement of global warming and regional databases are still old-fashioned and are not being developed sufficiently. With respect to this agenda, since 1993, at the request of the World Meteorological Organization (WMO), to monitor functions of global warming, the Korea Meteorological Administration (KMA) has set up a Global Atmospheric Watch (GAW) Station on the western coast of Korea (Anmyun-do) and has been actively monitoring global warming over Northeast Asia. In addition, atmospheric carbon dioxide (CO2) has been measured for a similar KMA global warming program at Kosan, Cheju Island since 1990. Aerosol and radiation have also been measured at both sites as well as in Seoul. The observations have been analyzed using diagnostics of climate change in Northeast Asia and also have been internationally compared. Results indicate that greenhouse gases are in good statistic agreement with the NOAA/Climate Monitoring and Diagnostics Laboratory (CMDL) long-term trends of monthly mean concentrations and seasonal cycles. Atmospheric particulate matter has also been analyzed for particular Asian types in terms of optical depth, number concentration and size distribution.

Background monitoring and long-range transport of atmospheric CFC-11 and CFC-12 at Kosan, Korea

The background concentrations of atmospheric CFC-11 and CFC-12 were monitored to assess their impact on stratospheric ozone depletion and global warming from September 1995 to March 1999 at Kosan, Korea, located at eastern margin of the Asian Continent. The concentrations of atmospheric CFC-11 at Kosan have decreased slightly, at a rate of -2.5 pptv yr(-1), over the period in response to the Montreal Protocol. The CFC-12 mixing ratio at Kosan continues to increase in the atmosphere at a rate of 5.7 pptv yr(-1) despite international regulations, because of its extreme atmosphere persistence. Recent trends of these two chlorofluorocarbons at Kosan, Korea were concordant with those of the northern hemispheric background monitored unit at Mauna Loa, Hawaii. The maximum seasonal mean mixing ratios of CFC-11 and CFC-12 at Kosan, Korea, were 270 +/- 4 pptv in the spring and 538 +/- 9 pptv in the winter, and the corresponding seasonal minima were 267 +/- 7 and 529 +/- 12 pptv. This occurred in the summer and was due to southeasterly winds from the northwestern Pacific Ocean. By performing a three-day isentropic backward trajectory analysis, it was shown that air masses at Kosan, and with the exception of summer, mainly originated from central and northern China. In particular, the mixing ratios of these two contaminant species are closely related with their air mass trajectories.