New Imaging Techniques.

The chapter discusses the advancement of new imaging techniques, the role of imaging in CCA diagnosis, anatomical and morphological classification, ultrasound screening of CCA, ultrasound findings of MF-CCA, PI-CCA, ID-CCA, the use of CT in CCA diagnosis, staging and treatment planning, CT volumetry and estimation of future liver remnant, post-treatment follow-up and surveillance, MRI imaging, Positron Emission Tomography (PET)/CT, limitations to contrast studies and resolution, internal receivers for CCA imaging, and in vitro imaging of CCA.

Modification of the AJCC/UICC 8th edition staging system for intrahepatic cholangiocarcinoma: proposal for an alternative staging system from cholangiocarcinoma-prevalent Northeast Thailand.

BACKGROUND: Intrahepatic cholangiocarcinoma (iCCA) arises from bile ducts within the liver. Thailand has the highest incidence of CCA worldwide, with a high mortality rate. Early diagnosis and accurate prognostic stratification can improve overall survival. We aim to modify the AJCC/UICC 8th edition staging system for iCCA by creating the Khon Kaen University (KKU) staging system for more precise patient stratification and prognostic prediction. METHODS: A total of 298 iCCA patients who underwent hepatectomy were included in this retrospective study at the Srinagarind Hospital, Khon Kaen University, Thailand. Univariate and multivariate analysis were performed to examine survival rate, hazard ratio, and prognostic factors. RESULTS: Univariate and multivariate analysis of the cohort showed that growth patterns, histological type, histological grade, lymph node metastasis and distant metastasis were independent prognostic factors when compared to the respective reference groups. The 8th AJCC staging system incorporated growth patterns into the KKU staging system. This model modified AJCC stages I, II, and III for better prediction of patient survival. CONCLUSION: Growth patterns were incorporated to improve the 8th AJCC staging system for prognostication of iCCA patients in Northeast Thailand. We propose the KKU staging system as an alternative model for iCCA staging to augment the accuracy of survival prognostication.

Trend of minimally invasive and open surgery experience of general surgery residents: Accreditation Council for Graduate Medical Education general surgery case log in Thailand.

Purpose: Minimally invasive surgery (MIS) offers patients several benefits, such as smaller incisions, and fast recovery times. General surgery residents should be trained in both open and MIS. We aimed to examine the trends of minimally invasive and open procedures performed by general surgery residents in Thailand. Methods: A retrospective review of the Royal College of Surgeons of Thailand and Accreditation Council for Graduate Medical Education general surgery case logs from 2007 to 2018 was performed for common open and laparoscopic general surgery operations. The data were grouped by three time periods, which were 2007-2010, 2011-2014, and 2015-2018, and analyzed to explore changes in the operative trends. Results: For Thai residents, the mean number of laparoscopic operations per person per year increased from 5.97 to 9.36 (56.78% increase) and open increased from 20.02 to 27.16 (35.67% increase). There was a significant increase in the average number of minimally invasive procedures performed among cholecystectomy (5.83, 6.57, 8.10; p < 0.001) and inguinal hernia repair (0.33, 0.35, 0.66; p < 0.001). Compared to general surgery residents in the United States, Thai residents had more experience with open appendectomy, but significantly less experience with all other operations/procedures. Conclusion: The number of open and minimally invasive procedures performed or assisted by Thai general surgery residents has slowly increased, but generally lags behind residents in the United States. The Thai education program must be updated to improve residents' technical skills in open and laparoscopic surgery to remain competitive with their global partners.

Diffusion-weighted imaging as an imaging biomarker for assessing survival of patients with intrahepatic mass-forming cholangiocarcinoma.

BACKGROUND: Mass-forming cholangiocarcinoma is the most common form of intrahepatic cholangiocarcinoma and is associated with a worse prognosis. This study aimed to assess the role of diffusion-weighted imaging and other imaging features as prognostic markers to predict the survival of patients with intrahepatic mass-forming cholangiocarcinoma (IMCC). MATERIALS AND METHODS: The study included patients with pathologically proven IMCC from January 2011 to January 2018. Two radiologists retrospectively reviewed various imaging findings and manually estimated the area of diffusion restriction. Patients were grouped according to their restriction area into (group 1) restriction ≥ 1/3 of the tumor and (group 2) restriction < 1/3 of the tumor. Statistical analysis was performed to assess the relationship between various imaging features and patients' survival. RESULTS: Seventy-three patients were included in the study. IMCC patients with tumor size ≥ 5 cm had increased intrahepatic- and peritoneal metastases (p = 039 and p = 0.001 for reader 1 and p = 0.048 and p = 0.057 for reader 2). There was no significant relationship between the diffusion restriction area and tumor size, enhancement pattern, vascular involvement, lymph node metastasis, peritoneal- and distant metastasis. The number of deaths was significantly higher in patients with group 2 restriction (63.6% for group 1 vs. 96.6% for group 2; p = 0.001 for reader 1)(68.2% for group 1 vs. 89.7%% for group 2; p = 0.030 for reader 2). Patients with group 2 restriction had shorter 1- and 3-year survival rates and lower median survival time. Multivariable survival analysis showed two independent prognostic factors relating to poor survival outcomes: peritoneal metastasis (p = 0.04 for reader 1 and p = 0.041 for reader 2) and diffusion restriction < 1/3 (p = 0.011 for reader 1 and p = 0.042 for reader 2). Lymph node metastasis and intrahepatic metastasis were associated with shorter survival in the univariate analysis. However, these factors were non-significant in the multivariate analysis. CONCLUSION: Restriction diffusion of less than 1/3 and peritoneal metastasis were associated with shorter overall survival of IMCC patients. Other features that might correlate with the outcome are suspicious lymph nodes and multifocal lesions.

Predictors of transmural intestinal necrosis in patients presenting with acute mesenteric ischemia on computed tomography.

PURPOSE: The purpose of this study was to identify the significant imaging predictors of transmural intestinal necrosis in patients with acute mesenteric ischemia (AMI). METHODS: The medical records and CT imaging of 48 patients between 2011 and 2019 suspected of having AMI that underwent exploratory laparotomy with bowel resection and pathological confirmation of ischemic bowel injury were retrospectively reviewed. Using histopathology as a gold standard, various parameters related to vascular insufficiency and bowel injury were analyzed and correlated with outcome of ischemic bowel necrosis using nonparametric tests. Univariate analysis was performed using Fisher's exact test followed by binary logistic regression test for multivariate analysis. RESULTS: 48 Patients (19 females, 40%) with a median age of 68.5 years (IQR of 17 years) built our retrospective cohort. 26 (54%) patients were found to have transmural intestinal necrosis on histopathology (case group) whereas 22 (46%) patients had partial mucosal injury (control group). Pneumatosis intestinalis (p = 0.005, odd's ratio of 2.07-63.14) and severity (> 70% or complete occlusion) of vascular narrowing (p = 0.019, odd's ratio of 1.39-42.30) were identified as the most significant predictors of transmural ischemic necrosis on imaging. Dilatation of bowel did not approach the statistical significance on multivariate analysis although it was found significant on univariate analysis (p = 0.041). CONCLUSION: Pneumatosis intestinalis and severity of vascular luminal narrowing are the most important imaging predictors of transmural ischemic bowel necrosis in patients presenting with AMI. The presence of these findings on CT scan should raise high index of suspicion for irreversible transmural ischemic necrosis. In the absence of these factors, endovascular management might be beneficial.

Prognostic Significance of Growth Pattern in Predicting Outcome of Opisthorchis viverrini-Associated Distal Cholangiocarcinoma in Thailand.

Distal cholangiocarcinoma (dCCA) is a rare type of CCA in Asia, even in Opisthorchis viverrini-prevalent Northeastern Thailand. The clinical ambiguity and imprecision of diagnosis surrounding this malignancy result in high mortality due often to advanced/metastatic disease on presentation. We aim to identify a prognostic factor that can improve the performance stratification and influence the outcome of dCCA patients after curative resection. A total of 79 patients who underwent curative-intended surgery for dCCA was enrolled. Possible risk factors for survival were analyzed with log-rank test, and independent factors with Cox regression model. dCCA patients were staged and classified according to the 8th edition the American Joint Committee on Cancer (AJCC) Staging Manual. Results were then compared with the revised classification employing the prognostic factor identified from multivariate analysis. Multivariate analysis revealed that growth pattern (p < 0.01) and distant metastasis (p = 0.012) were independent factors. Growth patterns comprise intraductal (ID), periductal infiltrating (PI), mass-forming (MF), and mixed types. When dCCA patients were grouped into those having good and poor outcomes (with and without ID components, respectively). The survival outcomes significantly differed among patients with and without ID components, which was better than with the 8th AJCC staging system in our cohort. Furthermore, Chi-square test showed that patterns without ID components (PI, MF, PI + MF) correlated with lymph node and distant metastasis. Therefore, classification of dCCA patients after curative-intended surgical resection based on growth pattern provides additional beneficial information for the prediction of survival in dCCA patients.

Modification of the eighth AJCC/UICC staging system for perihilar cholangiocarcinoma: An alternative pathological staging system from cholangiocarcinoma-prevalent Northeast Thailand.

Aim: This study aims to improve the classification performance of the eighth American Joint Committee on Cancer (AJCC) staging system for perihilar cholangiocarcinoma (pCCA) by proposing the Khon Kaen University (KKU) staging system developed in cholangiocarcinoma-prevalent Northeast Thailand. Method: Four hundred eighty-eight patients with pCCA who underwent partial hepatectomy between 2002 and 2017 at the Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Thailand, were included. Overall survival (OS) related to clinicopathological features was analyzed using the Kaplan-Meier method. Logrank test was performed in univariate analysis to compare OS data of clinicopathological features to determine risk factors for poor survival. Significant features were further analyzed by multivariate analysis (Cox regression) to identify prognostic factors which were then employed to modify the eighth AJCC staging system. Results: Multivariate analysis showed that growth pattern (HR = 4.67-19.72, p < 0.001), moderately and poorly differentiated histological grades (HR = 2.31-4.99, p < 0.05 and 0.001, respectively), lymph node metastasis N1 and N2 (HR = 1.37 and 2.18, p < 0.05 and 0.01, respectively), and distant metastasis (HR = 2.11, p < 0.001) were independent factors when compared to their respective reference groups. There was a clear separation of patients with pCCA into KKU stage: I [OS = 116 months (mo.)], II (OS = 46 mo.), IIIA (OS = 24 mo.), IIIB (11 mo.), IVA (OS = 7 mo.), and IVB (OS = 6 mo.). Conclusion: The new staging system was based on the incorporation of growth patterns to modify the eighth AJCC staging system. The classification performance demonstrated that the KKU staging system was able to classify and distinctly separate patients with pCCA into those with good and poor outcomes. It was also able to improve the stratification performance and discriminative ability of different stages of pCCA classification better than the eighth AJCC staging system. Hence, the KKU staging system is proposed as an alternative model to augment the accuracy of survival prognostication and treatment performance for patients with pCCA.

Prognostic significance of tumor-infiltrating lymphocytes in predicting outcome of distal cholangiocarcinoma in Thailand.

Patients with distal cholangiocarcinoma (dCCA) generally have poor outcomes because of late presentation and diagnosis. Therefore, prognostic factors for predicting outcomes are essential to improve therapeutic strategies and quality of life. Tumor-infiltrating lymphocytes (TILs) have been reported as a prognostic predictor in several cancers. However, their role in dCCA is still unclear. This study aimed to evaluate the association of TILs with outcome in patients with dCCA. Fifty-two patients were evaluated for the percentage rate of TILs in their cancers, and a median TIL level was used to divide the patients into two groups. Survival, multivariate, and correlation analyses were performed to determine the prognostic factors. Results showed that a low TIL level was associated with poor survival. Multivariate analysis revealed TILs as an independent factor for poor outcome. Moreover, TILs were markedly correlated with growth patterns, and both were applied to classify patients with dCCA. Subgroups of TILs with growth pattern incorporation improved stratification performance in separating good from poor patient outcomes. This study suggested that TILs could be a prognostic factor for predicting survival and for clustering patients with dCCA to improve prognostication capability. This finding may be incorporated into a new staging system for stratifying dCCA in Thailand.

The absolute tumor-capsule contact length in the diagnosis of extraprostatic extension of prostate cancer.

BACKGROUND: Extraprostatic extension (EPE) of prostate cancer is associated with a poor prognosis. The broad-based capsule-tumor interface has been recognized as one of the worrisome imaging features in multiparametric prostate MRI (mpMRI). However, there was significant heterogeneity among the measurement method used in prior studies. OBJECTIVES: This study's objectives were to investigate and compare the accuracy between the curvilinear and linear measurement, find the optimal cut-off contact surface threshold for the diagnosis of EPE, and assess the benefit of the additional contact surface measurement versus visual assessment alone. METHODS: The status of EPE in mpMRI and the overall PI-RADS were assessed. The tumor's dimensions, the actual tumor-capsule contact length (ACTCL), and the absolute tumor-capsule contact length (ABTCL) were measured. The parameters were analyzed and correlated with the EPE status from prostatectomy specimens. RESULTS: Ninety-five patients who underwent mpMRI followed by prostatectomy were included in the study. High Gleason score (score 8-9), radiologist's impression of EPE, and PI-RADS 5 were significantly correlated with EPE in surgical specimens (p = 0.014, p < 0.001, and p < 0.001, respectively). Both ACTCL and ABTCL of patients with EPE were significantly higher than those without EPE in all imaging sequences (p < 0.001 to p = 0.003). The ABTCL has higher accuracy than the ACTCL. Dynamic contrast enhancement (DCE) was the most accurate sequence to measure the contact interface. The recommended cut-off value of ABTCL was 15.0 mm, which had a sensitivity and specificity of 75.86% and 72.09%. Multivariable analysis revealed that the ABTCL > 15 mm and the radiologist's impression on visual assessment were the only two independent predictors for the prediction of EPE (p = 0.048 and p = 0.016, respectively). Improvement of diagnostic performance was achieved when the two factors were combined. CONCLUSION: The ABTCL has better accuracy than the curvilinear measurement in the prediction of EPE. The optimum sequence for the measurement of the contact surface is the DCE. We recommended using 15.0 mm as a cut-off point. CLINICAL IMPACT: The addition of the ABTCL measurement showed an increase in diagnostic performance. We encourage radiologists to use the capsular contact measurement in addition to their visual assessment to detect EPE in pre-operative MRI.

Accuracy of Nonenhanced CT vs Contrast-Enhanced CT for Diagnosis of Acute Appendicitis in Adults.

BACKGROUND: Acute appendicitis is one of the most common causes of acute abdominal pain requiring emergency intervention. It is often difficult for the clinician to make an accurate diagnosis due to nonspecific and overlapping clinical symptoms. Computed tomography (CT) has become the imaging modality of choice for the evaluation of suspected acute appendicitis. The main purpose of our study was to compare nonenhanced CT (NECT) with contrast-enhanced CT (CECT) for the diagnosis of acute appendicitis. MATERIAL AND METHODS: A total of 140 patients were enrolled in the study. Two abdominal radiologists-masked to both the clinical information and the final diagnosis-retrospectively reviewed the computed tomographic findings and made an imaging diagnosis based on (1) NECT only, (2) CECT only, and (3) both NECT and CECT. With the final diagnosis as the reference standard, the accuracy of each CT technique was estimated. RESULTS: The respective sensitivity, specificity, and accuracy for NECT, CECT, and NECT + CECT for the diagnosis of acute appendicitis were 80.7%, 86.7%, and 84.3%; 86.0%, 81.9%, and 83.6%; and, 87.7%, 80.7%, and 83.6%. There was no significant difference in the diagnosis of acute appendicitis among the 3 techniques. In order to make a correct diagnosis, the presence of at least 3 imaging findings for NECT or at least 4 for CECT had the best diagnostic accuracy. We also found that 9.25 mm was the optimal cut-off threshold for the detection of patients with acute appendicitis. CONCLUSION: Our study allowed direct comparison between NECT, CECT, and NECT + CECT combined. There was no difference in the ability of each CT technique for diagnosing patients with acute appendicitis. For a patient whom iodinated contrast media is contraindicated or a patient who has an increased risk of severe adverse reaction, we would encourage the use of NECT because it provides comparable diagnostic accuracy without further exposing such patient to the contrast media.

Utility of texture analysis on T2-weighted MR for differentiating tumor deposits from mesorectal nodes in rectal cancer patients, in a retrospective cohort.

OBJECTIVE: The purpose of the study was to evaluate the utility of MR texture analysis for differentiating tumor deposits from mesorectal nodes in rectal cancer. MATERIALS AND METHODS: Pretreatment MRI of 40 patients performed between 2006 and 2018 with pathologically proven tumor deposits and/or malignant nodes in the setting of rectal cancer were retrospectively reviewed. In total, 25 tumor deposits (TDs) and 71 positive lymph nodes (LNs) were analyzed for morphological and first-order texture analysis features on T2-weighted axial images. MR morphological features (lesion shape, size, signal heterogeneity, contrast enhancement) were analyzed and agreed in consensus by two experienced radiologists followed by assessment with Fisher's exact test. Texture analysis of the lesions was performed using TexRAD, a proprietary software algorithm. First-order texture analysis features (mean, standard deviation, skewness, entropy, kurtosis, MPP) were obtained after applying spatial scaling filters (SSF; 0, 2, 3, 4, 5, 6). Univariate analysis was performed with non-parametric Mann-Whitney U test. The results of univariate analysis were reassessed with generalized estimating equations followed by multivariate analysis. Using histopathology as a gold standard, diagnostic accuracy was assessed by obtaining area under the receiver operating curve. RESULTS: MR morphological parameter, lesion shape was a strong discriminator between TDs and LNs with a p value of 0.02 (AUC: 0.76, 95% CI of 0.66 to 0.84, SE: 0.06) and sensitivity, specificity of 90% and 68%, respectively. Skewness extracted at fine filter (SSF-2) was the only significant texture analysis parameter for distinguishing TDs from LNs with p value of 0.03 (AUC: 0.70, 95% CI of 0.59 to 0.79, SE: 0.06) and sensitivity, specificity of 70% and 72%, respectively. When lesion shape and skewness-2 were combined into a single model, the diagnostic accuracy was improved with AUC of 0.82 (SE: 0.05, 95% CI of 0.72 to 0.88 with p value of < 0.01). This model also showed a high sensitivity of 91% with specificity of 68%. CONCLUSION: Lesion shape on MR can be a useful predictor for distinguishing TDs from positive LNs in rectal cancer patients. When interpreted along with MR texture parameter of skewness, accuracy is further improved.

Imaging predictors of BRAF mutation in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is one of the leading causes of cancer deaths and is associated with various genetic mutations. BRAF mutations, found in approximately 10% of all CRCs, are associated with negative predictive outcomes. The goal of this study was to assess the relationship between the imaging findings and BRAF statuses of CRC patients. MATERIALS AND METHODS: The study population was colorectal cancer patients who underwent biopsy or surgery in a single institution from September 2004 to October 2018, and in whom the pathologic specimens were tested for BRAF mutation. The exclusion criteria were (1) patients without pre-operative cross-sectional imaging, and (2) patients whose tumors were invisible on imaging. Two hundred and eighty-three patients met the inclusion criteria. Among them, 128 were excluded, and a total of 155 patients were enrolled in the study. RESULTS: BRAF mutations were significantly more common in female patients (p = 0.007). Patients with mutated BRAF were significantly older than those with wild-type BRAF (p = 0.001). BRAF-mutant tumors were predominant in right-sided colon (p = 0.001) with higher numbers of polypoid- or mass-like morphology (p = 0.019) and heterogeneous enhancement (p = 0.009). Compared to their wild-type counterparts, BRAF-mutated CRCs have a lower occurrence of non-peritoneal, and overall metastases (p = 0.013 and p = 0.004, respectively). Logistic regression analysis showed three significant factors for the prediction of BRAF mutations in CRC patients: right-sided location (p = 0.002), heterogeneous tumor enhancement (p = 0.039), and lack of non-peritoneal metastasis (p = 0.043). CONCLUSION: By recognizing the specific imaging features of BRAF-mutant CRCs, it would be possible to identify a patient who has a higher risk of carrying BRAF mutation.

Successful Conservative Treatment of an Elderly Patient with Corrosive Proctocolitis.

Corrosive proctocolitis has occurred after accidental contamination of endoscopes in most patients. But accidental administration of corrosive agents for bowel cleansing can occur. The agents implicated for chemical colitis is 15% hydrochloric acid and 2% ethoxylated alcohol. We present a case of corrosive proctocolitis, present with anal pain and bloody diarrhea. Endoscopy revealed edema, erythema, and friability of the colonic mucosa. An experience of successful nonoperative treatments has been demonstrated.