Impact of Visceral Fat on Survival and Metastasis of Stage III Colorectal Cancer

Background/Aims@#Previous studies have investigated the relationship between visceral obesity and the risk of colorectal tumors. Visceral obesity may affect the outcome of colorectal cancer (CRC), including survival and metastasis. We investigated the associations between visceral adipose tissue and oncologic outcomes in stage III CRC. @*Methods@#Four hundred seventy-two patients with stage III CRC were identified. Subcutaneous and visceral adipose tissue areas were measured volumetrically via computed tomography for each patient at different levels of the lumbar spine. After adjusting for age, sex, and other clinical factors, the effects of visceral adipose tissue area on mortality and recurrence were assessed using Cox proportional hazard regression. @*Results@#In univariate and multivariate analyses, a higher visceral adipose tissue to total adipose tissue (VT) ratio (hazard ratio [HR], 1.041; 95% CI, 1.008 to 1.075; p=0.015) and higher visceral adipose tissue to subcutaneous adipose tissue (VS) ratio (HR, 1.016; 95% CI, 1.005 to 1.028; p=0.006) were both associated with poor CRC-specific survival. Interestingly, in the evaluation of each site of recurrence, a higher VT ratio (HR, 1.069; 95% CI, 1.010 to 1.131; p=0.020) and higher VS ratio (HR, 1.024; 95% CI, 1.003 to 1.045; p=0.023) were both related to a higher risk of peritoneal seeding and tumor recurrence. The VT ratio at the L3–L4 level was significantly associated with a higher risk of peritoneal seeding and tumor recurrence (HR, 4.969; 95% CI, 1.303 to 18.949; p=0.019), while other levels showed no such relationship. @*Conclusions@#Visceral obesity is closely related to increased risks of CRC-specific mortality and peritoneal seeding metastasis in stage III CRC patients.

Diagnostic Performance of Deep Learning-Based Lesion Detection Algorithm in CT for Detecting Hepatic Metastasis from Colorectal Cancer

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.

Diagnostic Performance of Deep Learning-Based Lesion Detection Algorithm in CT for Detecting Hepatic Metastasis from Colorectal Cancer

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.

MRI Assessment of Complete Response to Preoperative Chemoradiation Therapy for Rectal Cancer: 2020 Guide for Practice from the Korean Society of Abdominal Radiology

Objective@#To provide an evidence-based guide for the MRI interpretation of complete tumor response after neoadjuvant chemoradiation therapy (CRT) for rectal cancer using visual assessment on T2-weighted imaging (T2) and diffusion-weighted imaging (DWI). @*Materials and Methods@#PubMed MEDLINE, EMBASE, and Cochrane Library were searched on November 28, 2019 to identify articles on the following issues: 1) sensitivity and specificity of T2 or DWI for diagnosing pathologic complete response (pCR) and the criteria for MRI diagnosis; 2) MRI alone vs. MRI combined with other test(s) in sensitivity and specificity for pCR; and 3) tests to select patients for the watch-and-wait management. Eligible articles were selected according to meticulous criteria and were synthesized. @*Results@#Of 1615 article candidates, 55 eligible articles (for all three issues combined) were identified. Combined T2 and DWI performed better than T2 alone, with a meta-analytic summary sensitivity of 0.62 (95% confidence interval [CI], 0.43– 0.77; I2 = 80.60) and summary specificity of 0.89 (95% CI, 0.80–0.94; I2 = 92.61) for diagnosing pCR. The criteria for the complete response on T2 in most studies had the commonality of remarkable tumor decrease to the absence of mass-like or nodular intermediate signal, although somewhat varied, as follows: (near) normalization of the wall; regular, thin, hypointense scar in the luminal side with (near) normal-appearance or homogeneous intermediate signal in the underlying wall; and hypointense thickening of the wall. The criteria on DWI were the absence of a hyperintense signal at high b-value (≥ 800 sec/mm2) in most studies. The specific algorithm to combine T2 and DWI was obscure in half of the studies. MRI combined with endoscopy was the most utilized means to select patients for the watch-and-wait management despite a lack of strong evidence to guide and support a multi-test approach. @*Conclusion@#This systematic review and meta-analysis provide an evidence-based practical guide for MRI assessment of complete tumor response after CRT for rectal cancer.

Feasibility of Simultaneous Multislice Acceleration Technique in Diffusion-Weighted Magnetic Resonance Imaging of the Rectum

Response Assessment with MRI after Chemoradiotherapy in Rectal Cancer: Current Evidences

Baseline magnetic resonance imaging (MRI) has become the primary staging modality for surgical plans and stratification of patient populations for more efficient neoadjuvant treatment. Patients who exhibit a complete response to chemoradiotherapy (CRT) may achieve excellent local tumor control and better quality of life with organ-preserving treatments such as local excision or even watch-and-wait management. Therefore, the evaluation of tumor response is a key factor for determining the appropriate treatment following CRT. Although post-CRT MRI is generally accepted as the first-choice method for evaluating treatment response after CRT, its application in the clinical decision process is not fully validated. In this review, we will discuss various oncologic treatment options from radical surgical technique to organ-preservation strategies for achieving better cancer control and improved quality of life following CRT. In addition, the current status of post-CRT MRI in restaging rectal cancer as well as the main imaging features that should be evaluated for treatment planning will also be described for the tailored treatment.

Petersen's Hernia after Subtotal Gastrectomy with Billroth II Gastrojejunostomy for Gastric Cancer: A Specific CT Finding

Petersen's hernia is a rare internal hernia occurring after any type of gastrojejunal anastomosis. This type of internal hernia after laparoscopic gastrectomy with Roux-en-Y reconstruction for obesity treatment has been reported frequently. However, reports about Petersen's hernia after gastrectomy with Billroth II gastrojejunostomy for gastric cancer are relatively rare. To diagnose internal hernia, whirl sign has been reported to be a sensitive predictor of internal hernia. However, it is hard to diagnose a specific type of internal hernia. We report a case of Petersen's hernia after radical subtotal gastrectomy with Billroth II gastrojejunostomy for gastric cancer with an unreported specific computed tomography finding that suggests Petersen's hernia.

Magnetic resonance enterography predicts the prognosis of Crohn's disease

BACKGROUND/AIMS: Magnetic resonance enterography (MRE) has emerged as an important tool in the diagnosis and follow-up of Crohn's disease (CD). The aim of this study was to evaluate whether MRE findings could predict the prognosis of CD. METHODS: In this retrospective study, a total of 173 patients with clinical remission of CD (n=61) or active CD (n=112) were identified. The outcomes of clinical relapse, admission, surgery, and need for other medications according to the MRE findings were evaluated. RESULTS: The presence of active inflammation on MRE was observed in 93 (83%) patients with clinically active CD and in 44 (72.1%) patients with clinical remission of CD, without a statistically significant difference (P=0.091). In multivariate analysis, active inflammation on MRE increased the risk for clinical relapse (hazard ratio [HR], 6.985; 95% confidence interval [CI], 1.024–47.649) in patients with clinical remission of CD. In patients with clinically active CD, active inflammation on MRE increased the risk for CD-related hospitalization (HR, 2.970; 95% CI, 1.006–8.772). CONCLUSIONS: The presence of active inflammation on MRE was significantly associated with poor prognosis both in patients with clinical remission of CD and in those with active CD.

Extraosseous Ewing's Sarcoma Presented as a Rectal Subepithelial Tumor: Radiological and Pathological Features

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.

Portal venous perfusion steal causing graft dysfunction after orthotopic liver transplantation: serial imaging findings in a successfully treated patient

A 53-year-old male with hepatocellular carcinoma underwent orthotopic liver transplantation. Preoperative computed tomography revealed main portal vein luminal narrowing by flat thrombi and the development of cavernous transformation. On post-transplantation day 1, thrombotic portal venous occlusion occurred, and emergency thrombectomy was performed. Subsequent Doppler ultrasonography and contrast-enhanced ultrasonography confirmed the restoration of normal portal venous flow. The next day, however, decreased portal venous velocity was observed via Doppler ultrasonography, and serum liver enzymes and bilirubin levels remained persistently elevated. Direct portography identified massive perfusion steal through prominent splenorenal collateral veins. Stent insertion and balloon angioplasty of the portal vein were performed, and subsequent Doppler ultrasonography demonstrated normalized portal flow parameters. Afterwards, the serum liver enzymes and bilirubin levels rapidly normalized.

Necrotic lymphoma in a patient with post-transplantation lymphoproliferative disorder: ultrasonography and CT findings with pathologic correlation

Seventeen months after kidney transplantation for the treatment of nephrotic syndrome, a retroperitoneal mass was incidentally detected in a 30-year-old man during routine follow-up. Ultrasonography revealed a mass measuring 5.5 cmx4.3 cm located between the liver and the atrophic right kidney, which showed markedly heterogeneous internal echogenicity. Contrast-enhanced computed tomography displayed a mild degree of enhancement only at the periphery of the mass, while the center lacked perceivable intensification. The patient underwent surgical resection. The final pathological diagnosis was non-Hodgkin lymphoma (diffuse large B-cell lymphoma), and extensive necrosis was observed on microscopic examination. We found that the prominent heterogeneous echogenicity of the mass (an unusual finding of lymphoma) demonstrated on ultrasonography is a result of extensive necrosis, which may sometimes occur in patients with post-transplantation lymphoproliferative disorder.

Preoperative Evaluation of Lower Rectal Cancer by Pelvic MR with and without Gel Filling

PURPOSE: To assess the usefulness of rectal filling using ultrasonographic gel in patients with lower rectal cancer. MATERIALS AND METHODS: Twenty five patients with lower rectal cancer were enrolled. High resolution pelvic MR was performed twice before and after gel filling. Independently and retrospectively, two radiologists reviewed each set of MR images using five-grade scales for sphincter involvement, CRM (circumferential resection margin) involvement and depiction of the tumor. Same two radiologists retrospectively performed consensus review of each set of MR images for tumor distance from the anal verge and T&N staging. RESULTS: Tumor depiction scores from MR with gel filling were significantly higher than those of MR without distention (p0.05). Distance from the anal verge was significantly different between MR with gel filling and rigid endoscopy (6.8 +/- 1.6 cm vs. 5.8 +/- 1.6 cm, p=0.001). There were no significant differences between pathological staging and MR staging with or without gel filling. CONCLUSION: MR with gel filling improved tumor depiction. And also MR with gel filling revealed same ability for the predictions of CRM or sphincter invasion in patients with lower rectal cancer, comparing with MR without gel filling.

Perfusion Parameters of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Patients with Rectal Cancer: Correlation with Microvascular Density and Vascular Endothelial Growth Factor Expression

OBJECTIVE: To determine whether quantitative perfusion parameters of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) correlate with immunohistochemical markers of angiogenesis in rectal cancer. MATERIALS AND METHODS: Preoperative DCE-MRI was performed in 63 patients with rectal adenocarcinoma. Transendothelial volume transfer (Ktrans) and fractional volume of the extravascular-extracellular space (Ve) were measured by Interactive Data Language software in rectal cancer. After surgery, microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression scores were determined using immunohistochemical staining of rectal cancer specimens. Perfusion parameters (Ktrans, Ve) of DCE-MRI in rectal cancer were found to be correlated with MVD and VEGF expression scores by Spearman's rank coefficient analysis. T stage and N stage (negative or positive) were correlated with perfusion parameters and MVD. RESULTS: Significant correlation was not found between any DCE-MRI perfusion parameters and MVD (rs = -0.056 and p = 0.662 for Ktrans; rs = -0.103 and p = 0.416 for Ve), or between any DCE-MRI perfusion parameters and the VEGF expression score (rs = -0.042, p = 0.741 for Ktrans ; r = 0.086, p = 0.497 for Ve) in rectal cancer. TN stage showed no significant correlation with perfusion parameters or MVD (p > 0.05 for all). CONCLUSION: DCE-MRI perfusion parameters, Ktrans and Ve, correlated poorly with MVD and VEGF expression scores in rectal cancer, suggesting that these parameters do not simply denote static histological vascular properties.

Computed Tomography Enterography for Evaluation of Inflammatory Bowel Disease

Computed tomography enterography (CTE) has become a main modality for the evaluation of inflammatory bowel disease (IBD). It simultaneously offers visualization of the small bowel and extraintestinal status, which is helpful for diagnosing IBD. Crohn disease has long segmental enhancing wall thickening related with the eccentric longitudinal distribution. In addition, mural stratification, fibrofatty proliferation, positive comb sign by increased mesenteric vascularity and internal/perianal fistula are characteristics of Crohn disease and can be identified on CTE. Short segmental inflammatory wall thickening and the central low attenuated lymph nodes are favorable CT finding of intestinal tuberculosis. A geographic, relatively large, and deep penetrating ulcer with bowel wall thickening and mural hyperenhancement in ileocecal area are characteristics of intestinal Behcet disease. Each of CTE findings for the IBDs is helpful for differential diagnosis. The main disadvantage of this technique is the requisite radiation exposure of patients, particularly in young patients. However, recent development of advanced CT techniques is promising for radiation dose reduction without compromising diagnostic image quality.

Laparoscopic Total Gastrectomy in a Gastric Cancer Patient with Intestinal Malrotation

As the incidence of early gastric cancer increases, laparoscopic surgery has become one of the treatments of choice for gastric cancer. With the increase of laparoscopic surgery, the chance of discovering aberrant anatomy during the operation also increases. We present a case of laparoscopic total gastrectomy in gastric cancer patients with intestinal malrotation. Intestinal malrotation occurs in one in every 500 births. We found that laparoscopic total gastrectomy in such patients can be performed successfully when it is performed with a proper Roux limb orientation through an alternative minilaparotomy.

Laparoscopic Total Gastrectomy in a Gastric Cancer Patient with Intestinal Malrotation

As the incidence of early gastric cancer increases, laparoscopic surgery has become one of the treatments of choice for gastric cancer. With the increase of laparoscopic surgery, the chance of discovering aberrant anatomy during the operation also increases. We present a case of laparoscopic total gastrectomy in gastric cancer patients with intestinal malrotation. Intestinal malrotation occurs in one in every 500 births. We found that laparoscopic total gastrectomy in such patients can be performed successfully when it is performed with a proper Roux limb orientation through an alternative minilaparotomy.

Malignant Mixed Mullerian Tumor with Small Bowel Metastasis: A Case Report

Malignant mixed Mullerian tumors (MMMT) are rare aggressive tumors that typically arise fromthe female genital tract. This malignancy has an extremely poor prognosis due to its rapid growthand the high associated incidence of both local recurrence and distant metastases. Althoughintraperitoneal metastasis from MMMT is relatively common, no reports exist regarding theradiologic findings of intestinal metastasis from MMMT. Here, we report a case of MMMT withsecondary small bowel metastasis and the associated radiologic findings.

Quantitative Assessment of Tumor Responses after Radiation Therapy in a DLD-1 Colon Cancer Mouse Model Using Serial Dynamic Contrast-Enhanced Magnetic Resonance Imaging

PURPOSE: The purpose of this study was to investigate the predictability of pretreatment values including Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) derived parameters (Ktrans, Kep and Ve), early changes in parameters (Ktrans, tumor volume), and heterogeneity (standard deviation of Ktrans) for radiation therapy responses via a human colorectal cancer xenograft model. MATERIALS AND METHODS: A human colorectal cancer xenograft model with DLD-1 cancer cells was produced in the right hind limbs of five mice. Tumors were irradiated with 3 fractions of 3 Gy each for 3 weeks. Baseline and follow up DCE-MRI were performed. Quantitative parameters (Ktrans, Kep and Ve) were calculated based on the Tofts model. Early changes in Ktrans, standard deviation (SD) of Ktrans, and tumor volume were also calculated. Tumor responses were evaluated based on histology. With a cut-off value of 0.4 for necrotic factor, a comparison between good and poor responses was conducted. RESULTS: The good response group (mice #1 and 2) exhibited higher pretreatment Ktrans than the poor response group (mice #3, 4, and 5). The good response group tended to show lower pretreatment Kep, higher pretreatment Ve, and larger baseline tumor volume than the poor response group. All the mice in the good response group demonstrated marked reductions in Ktrans and SD value after the first radiation. All tumors showed increased volume after the first radiation therapy. CONCLUSION: The good response after radiation therapy group in the DLD-1 colon cancer xenograft nude mouse model exhibited a higher pretreatment Ktrans and showed an early reduction in Ktrans, demonstrating a more homogenous distribution.

Cumulative Radiation Exposure during Follow-Up after Curative Surgery for Gastric Cancer

OBJECTIVE: To quantify the cumulative effective dose (cED) of radiation due to repeated CT and PET/CT examinations after curative resection of gastric cancer and to assess the lifetime attributable risk (LAR) estimates based on Biological Effects of Ionizing Radiation VII models. SUBJECTS AND METHODS: Patients who underwent a curative resection for gastric cancer between January 2006 and December 2006 and were followed-up until May 2010 were included in this study. The cED was calculated by using the dose-length product values and conversion factors for quantitative risk assessment of radiation exposure. cED and LAR were compared between early and advanced gastric cancer patients and among American Joint Committee on Cancer TNM stage groups (stage I, II, and III). The nonparametric Mann-Whitney U and Kruskal-Wallis tests, followed by a post-hoc analysis with Bonferroni adjustment, were employed as part of the statistical analysis. RESULTS: The overall median cED was 57.8 mSv (interquartile range [IQR], 43.9-74.7). The cED was significantly higher in the advanced (median, 67.0; IQR, 49.1-102.3) than in the early gastric cancer group (median, 52.3; IQR, 41.5-67.9) (p < 0.001), and increased as the TNM stage increased. For radiation exposure, 62% of all patients received an estimated cED of over 50 mSv, while 11% of patients received over 100 mSv. The median LAR of cancer incidence was 0.28% (IQR, 0.20-0.40) and there were significant differences between the early gastric cancer and advanced gastric cancer group (p < 0.001) as well as among the three TNM stage groups (p = 0.015). The LAR of cancer incidence exceeded 1% in 2.4% of the patients. CONCLUSION: The cED increases proportionally along with tumor stage and, even in early gastric cancer or stage I patients, cED is much higher than that found among the general population. Considering the very good prognosis of early gastric cancer after curative surgery, the cED should be considered when designing a postoperative follow-up CT protocol.

Pancreatic Tumors: Emphasis on CT Findings and Pathologic Classification

Pancreatic tumors can be classified by their morphologic features on CT. The subtypes include solid tumors, mixed cystic and solid lesions, unilocular cysts, multilocular cystic lesions, and microcystic lesions. Endoscopic US and MRI can provide detailed information for classifying pancreatic lesions. Each subtype has different kinds of tumors and malignant potential, thus the classification can be useful for a better differential diagnosis and treatment planning. For this purpose, we suggest an appropriate modified classification system by using the imaging features of pancreatic tumors with an emphasis on CT findings and illustrate various findings of typical and atypical manifestations.