Differentiation of hepatic abscess from metastasis on contrast-enhanced dynamic computed tomography in patients with a history of extrahepatic malignancy: emphasis on dynamic change of arterial rim enhancement

Imaging of pancreatic ductal adenocarcinoma - An update for all stages of patient management

Background

Pancreatic ductal adenocarcinoma (PDAC) is a common and lethal cancer. From diagnosis to disease staging, response to neoadjuvant therapy assessment and patient surveillance after resection, imaging plays a central role, guiding the multidisciplinary team in decision-planning.

Review aims and findings

This review discusses the most up-to-date imaging recommendations, typical and atypical findings, and issues related to each step of patient management. Example cases for each relevant condition are presented, and a structured report for disease staging is suggested.

Conclusion

Despite current issues in PDAC imaging at different stages of patient management, the radiologist is essential in the multidisciplinary team, as the conveyor of relevant imaging findings crucial for patient care.

Treatment of Candida albicans liver abscess complicated with COVID-19 after liver metastasis ablation: A case report

BACKGROUND

Liver interventional surgery is a relatively safe and minimally invasive surgery. However, for patients who have undergone Whipple surgery, the probability of developing a liver abscess after liver interventional surgery is very high. Fungal liver abscess has a high mortality rate, especially when complicated with malignant tumors, diabetes, coronavirus disease 2019 (COVID-19) and other complications. Fungal liver abscess is rare, and there are no guidelines or expert consensus on the course of antifungal therapy.

CASE SUMMARY

A 54-year-old woman with pancreatic head cancer received albumin-bound paclitaxel in combination with gemcitabine chemotherapy after laparoscopic pancreaticoduodenectomy. Liver metastasis was found 1 mo after completion of 8 cycles of chemotherapy, followed by ablation of the liver metastasis. After half a month of liver metastasis ablation, the patient experienced fever after chemotherapy and was diagnosed with liver abscess complicated with COVID-19 by contrast-enhanced abdominal computed tomography and real-time polymerase chain reaction detection. The results of pus culture showed Candida albicans, which was sensitive to fluconazole. The patient underwent percutaneous catheter drainage, antifungal therapy with fluconazole, and antiviral therapy with azvudine. During antifungal therapy, the patient showed a significant increase in liver enzyme levels and was discharged after liver protection therapy. Oral fluconazole was continued for 1 wk outside the hospital, and fluconazole was used for a total of 5 wk. The patient recovered well and received 4 cycles of fluorouracil, leucovorin, oxaliplatin, and irinotecan after 2 mo of antifungal therapy.

CONCLUSION

Effective treatment of Candida albicans liver abscess requires early detection, percutaneous catheter drainage, and 5 wk of antifungal therapy. Meanwhile, complications such as COVID-19 should be actively managed and nutritional support should be provided.

Postoperative surveillance of pancreatic ductal adenocarcinoma (PDAC) recurrence: practice pattern on standardized imaging and reporting from the society of abdominal radiology disease focus panel on PDAC

PURPOSE

Surgical resection is the only potential curative treatment for patients with pancreatic ductal adenocarcinoma (PDAC), but unfortunately most patients recur within 5 years of surgery. This article aims to assess the practice patterns across major academic institutions and develop consensus recommendations for postoperative imaging and interpretation in patients with PDAC.

METHODS

The consensus recommendations for postoperative imaging surveillance following PDAC resection were developed using the Delphi method. Members of the Society of Abdominal Radiology (SAR) PDAC Disease Focused Panel (DFP) underwent three rounds of surveys followed by live webinar group discussions to develop consensus recommendations.

RESULTS

Significant variations currently exist in the postoperative surveillance of PDAC, even among academic institutions. Differentiating common postoperative inflammatory and fibrotic changes from tumor recurrence remains a diagnostic challenge, and there is no reliable size threshold or growth rate of imaging findings that can provide differentiation. A new liver lesion or peritoneal nodule should be considered suspicious for tumor recurrence, and the imaging features should be interpreted in the appropriate clinical context (e.g., CA 19-9, clinical presentation, pathologic staging).

CONCLUSION

Postoperative imaging following PDAC resection is challenging to interpret due to the presence of confounding postoperative inflammatory changes. A standardized reporting template for locoregional findings and report impression may improve communication of relaying risk of recurrence with referring providers, which merits validation in future studies.

Comparison of contrast-enhanced transabdominal ultrasonography following endoscopic ultrasonography with GD-EOB-DTPA-enhanced MRI for the sequential diagnosis of liver metastasis in patients with pancreatic cancer

PURPOSE

To compare contrast-enhanced transabdominal ultrasonography (CE-US) following contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) with enhanced magnetic resonance imaging using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (EOB-MRI) in the diagnosis of liver metastases in patients with pancreatic cancer.

METHODS

Patients who underwent contrast-enhanced computed tomography for possible pancreatic cancer and required further evaluation with CH-EUS were enrolled in this study, and the diagnostic performance of CE-US following CH-EUS for liver metastasis was compared with that of EOB-MRI.

RESULTS

A total of 228 patients were included in the final analysis. Two hundred thirty-four hepatic lesions were found in 81 patients, and 178 lesions were finally diagnosed as metastases. EOB-MRI had a higher sensitivity (0.837 vs 0.949), while CE-US had a higher specificity and positive predictive value (PPV) (0.982 and 0.993 vs 0.911 and 0.971, respectively) in the diagnosis of liver metastasis. CE-US with defect reperfusion imaging had a higher diagnostic performance than EOB-MRI (0.866 vs 0.667) in the differentiation between liver metastasis and abscess.

CONCLUSION

EOB-MRI had a higher sensitivity than CE-US for diagnosing liver metastasis in patients with pancreatic cancer, but CE-US following CH-EUS demonstrated a higher specificity and PPV than EOB-MRI and was especially useful in the differentiation between liver metastasis and abscess.

Differentiation of Small Hepatic Abscess From Hepatic Metastasis With a Combination of Imaging Parameters

OBJECTIVE

We aimed to evaluate the diagnostic performance of the combination imaging features to differentiate small (the lesion size of 3 cm or less) hepatic abscess from metastasis.

METHODS

This retrospective study included patients with preexisting malignancy and small hepatic lesions who underwent contrast-enhanced computed tomography (CT) and gadoxetic acid-enhanced magnetic resonance imaging (MRI) within 4 days between March 2017 and July 2020. Two radiologists independently evaluated the imaging features of each focal hepatic lesion. Laboratory parameters were also recorded. Significant parameters differentiating hepatic abscess from hepatic metastasis were identified by univariate generalized estimating equation regression. We compared the diagnostic performances of laboratory parameters, imaging features, and their combinations.

RESULTS

We included 16 patients (10 males and 6 females) with 35 hepatic abscesses and 21 patients (13 males and 8 females) with 62 metastases with a mean age of 70.3 years in this study. Abnormal segmental neutrophil, pathy parenchymal enhancement on CT, and absence of dark rim on MRI were associated with hepatic abscess (all P < 0.01). The combination of CT and MRI parameters showed significantly higher specificity and positive predictive value than CT alone (P ≤ 0.031), without significant difference in sensitivity and negative predictive value.

CONCLUSIONS

We have demonstrated that the combination of CT and MRI imaging features is helpful for the differentiation of small hepatic abscess from metastasis.

Development and validation of a prediction model based on clinical and CT features for invasiveness of K. pneumoniae liver abscess

OBJECTIVES

Klebsiella pneumoniae liver abscess (KPLA) complicated with extrahepatic migratory infection (EMI) is defined as invasive KPLA. The current study aimed to develop and validate a risk prediction model for the invasiveness of KPLA.

METHODS

From 2010 to 2020, KPLA patients from four institutes were selected retrospectively. In the development cohort, risk factors from a logistic regression analysis were utilized to develop the prediction model. External validation was performed using an independent cohort.

RESULTS

A total of 382 KPLA patients comprised two separate cohorts: development cohort (institute 1, n = 286) and validation cohort (institute 2-4, n = 86). The overall incidence of EMI was 19.1% (development cohort, n = 55; validation cohort, n = 18, p > 0.05). In the development cohort, four risk factors (age ≤ 40 years, fasting blood glucose (FBG) > 7 mmol/L, no rim enhancement, and thrombophlebitis on CT), significantly associated with EMI, were incorporated into the scoring system. The area under curve (AUC) of the receiver operating characteristic curve (ROC) in the development and validation cohorts was 0.931 (95% confidence interval [CI]: 0.93-0.95) and 0.831 (95% CI: 0.86-0.91), respectively. The calibration curves fitted well. The incidence of EMI was 3.3% and 56.5% for the low- (total scores ≤ 4) and high-risk (total scores > 4) groups in the development cohort, and 3.2% and 66.7% in the validation cohort (all p < 0.001), respectively.

CONCLUSIONS

Age ≤ 40 years, FBG > 7 mmol/L, no rim enhancement, and thrombophlebitis were independent risk factors for EMI. This validated prediction model may aid clinicians in identifying KPLA patients at increased risk for invasiveness.

KEY POINTS

• Four risk factors are significantly associated with extrahepatic migratory infections (EMI): age ≤ 40 years, fasting blood glucose (FBG) > 7 mmol/L, no rim enhancement, and thrombophlebitis on CT. • Based on these risk factors, the current study developed and validated a prediction model for the invasiveness of Klebsiella pneumoniae liver abscess (KPLA). • This validated prediction model may in the help early identification of KPLA patients at increased risk for invasiveness.

Current Status and Recent Update of Imaging Evaluation for Peri-Hilar Cholangiocarcinoma

간문주변부의 해부학적 복잡성으로 인해 간문주변부 담관암은 그 진단과 치료가 어려운 질환으로 알려져 있다. 간문주변부 담관암이 의심되는 환자에 있어서, 영상 검사는 이상 소견의 발견 및 감별 진단, 종양의 종축 침범 부위의 파악, 인접 혈관 침범과 원격 전이 유무의 파악, 그리고 최종적으로 수술적 절제 가능 유무의 평가에 있어 핵심적인 역할을 하고 있다. 이 종설에서는 간문주변부 담관암의 분류 및 종양의 평가를 위해 권고되는 표준 영상 검사의 기법과 간문주변부 담관암의 전형적인 영상 소견에 대해 기술할 예정이다. 종축 방향의 종양 침범 파악, 인접 혈관 침범 및 원격 전이 유무의 평가에 있어서 각 영상 검사 소견과 그 진단능에 대해 논의할 예정이다. 이후 전통적인 절제 가능성 평가의 개념에 대해 고찰하고, 최근의 경향을 소개한다.

Therapeutic response assessment in pancreatic ductal adenocarcinoma: society of abdominal radiology review paper on the role of morphological and functional imaging techniques

Pancreatic ductal adenocarcinoma (PDA) is the third leading cause of cancer-related death in the United States and is projected to be the second by 2030. Systemic combination chemotherapy is considered an essential first-line treatment for the majority of patients with PDA, in both the neoadjuvant and palliative settings. In addition, a number of novel therapies are being tested in clinical trials for patients with advanced PDA. In all cases, accurate and timely assessment of treatment response is critical to guide therapy, reduce drug toxicities and cost from a failing therapy, and aid adaptive clinical trials. Conventional morphological imaging has significant limitations, especially in the context of determining primary tumor response and resectability following neoadjuvant therapies. In this article, we provide an overview of current therapy options for PDA, highlight several morphological imaging findings that may be helpful to reduce over-staging following neoadjuvant therapy, and discuss a number of emerging imaging, and non-imaging, tools that have shown promise in providing a more precise quantification of disease burden and treatment response in PDA.

Deep learning-based radiomics predicts response to chemotherapy in colorectal liver metastases

PURPOSE

The purpose of this study was to develop and validate a deep learning (DL)-based radiomics model to predict the response to chemotherapy in colorectal liver metastases (CRLM).

METHODS

In this retrospective study, we enrolled 192 patients diagnosed with CRLM who received first-line chemotherapy and were followed by response assessment. Tumor response was identified according to the Response Evaluation Criteria in Solid Tumors (RECIST). Contrast-enhanced multidetector computed tomography (MDCT) images were fed as inputs of the ResNet10-based DL radiomics model, and the possibility of response was predicted as the output. The final combined DL radiomics model was constructed by integrating the response-related clinical factors and the developed DL radiomics signature. A time-independent validation cohort (n = 48) was extracted from the 192 patients to evaluate the DL model with area under the receiver operating characteristic curve (AUC), specificity, and sensitivity. Meanwhile, a traditional radiomics model was constructed using least absolute shrinkage and selection operator (lasso) as comparisons with the DL-based model.

RESULTS

According to RECIST criteria, 131 patients were identified as responders with complete response, partial response, and stable disease, while 61 patients were nonresponders with progression disease. The selected predictive clinical factor turned out to be the carcinoembryonic antigen (CEA) level with AUC of 0.489 (95% confidence interval [CI], 0.380-0.599) and 0.558 (95% CI, 0.374-0.741) in the training and validation cohorts, respectively. The DL-based model provided better performance than the traditional classifier-based radiomics model with significantly higher AUC (training: 0.903 [95% CI, 0.851-0.955] vs 0.745 [95% CI, 0.659-0.831]; validation: 0.820 [95% CI, 0.681-0.959] vs 0.598 [95% CI, 0.422-0.774]). The combination of DL-based model with the CEA level provided slightly increased performance with AUC of 0.935 [95% CI, 0.897-0.973] in the training cohort and 0.830 [95% CI, 0.688-0.973] in the validation cohort.

CONCLUSIONS

The developed DL-based radiomics model could improve the efficiency to predict the response to chemotherapy in CRLM, which may assist in subsequent personalized treatment decision-making in CRLM management.

CT-based radiomics model to distinguish necrotic hepatocellular carcinoma from pyogenic liver abscess

AIM

To investigate the feasibility of a computed tomography (CT)-based radiomics model in distinguishing necrotic hepatocellular carcinoma (nHCC) from pyogenic liver abscess (PLA).

MATERIAL AND METHODS

One hundred-four enrolled patients with nHCC (n=56) and PLA (n=48) were divided randomly into a training cohort (n=62) and validation cohort (n=42). ROI (region of interest) of the wall (ROI-wall) and ROI of the necrotic cavity (ROI-necrotic cavity) of the lesion were delineated from each arterial phase (AP) and portal venous phase (PP) image. The least absolute shrinkage and the selection operator logistic regression method was used to select radiomics features, and radiomics scores (R-scores) were calculated. Four radiomics models, including R-score (ROI-wall) in the AP, R-score (ROI-necrotic cavity) in the AP, R-score (ROI-wall) in the PP and R-score (ROI-necrotic cavity) in the PP, were constructed and evaluated by area under the curve (AUC) of receiver operating characteristic curve.

RESULTS

The AUCs of R-score (ROI-wall) in the AP, R-score (ROI-necrotic cavity) in the AP, R-score (ROI-wall) in the PP, and R-score (ROI-necrotic cavity) in the PP were 0.935 and 0.917, 0.906 and 0.824, 0.985 and 0.928, 0.899 and 0.850, in the training and validation cohorts, respectively. In the training cohort, the AUC of R-score (ROI-wall) in the PP was higher than that of R-score (ROI-wall) in the AP (p=0.024) or R-score (ROI-necrotic cavity) in the AP (p=0.046) or R-score (ROI-necrotic cavity) in the PP (p=0.044).

CONCLUSION

CT-based radiomics models can be used to distinguish nHCC from PLA.

Enhanced Rim on MDCT of Colorectal Liver Metastases: Assessment of Ability to Predict Progression-Free Survival and Response to Bevacizumab-Based Chemotherapy

OBJECTIVE. The purpose of this article is to evaluate the enhanced rim on the portal venous phase (PVP) on MDCT as a predictor of 1-year progression-free survival (PFS) and response to bevacizumab-based chemotherapy in patients with colorectal liver metastases (CRLM). MATERIALS AND METHODS. We retrospectively identified 111 patients with primary unresectable CRLM treated with bevacizumab-based chemotherapy at two institutions between 2012 and 2018. Pretreatment contrast-enhanced MDCT images were reviewed and data on clinical characteristics were collected from the electronic medical records. Univariable and multivariable analyses were conducted to assess several imaging features and clinical characteristics as potential predictors of 1-year PFS and objective response rate (ORR). RESULTS. After 1 year of follow-up, liver metastatic tumor progression was detected in 52 patients (46.8%) after bevacizumab-based chemotherapy. A log-rank test showed that enhanced rim on PVP (chi-square test, 5.862; p = 0.015) and the occurrence of liver resection surgery (chi-square test, 7.836; p = 0.005) were significant predictors of 1-year PFS. Multivariable analysis showed that enhanced rim on PVP images was an independent predictor of 1-year PFS (hazard ratio, 0.510; 95% CI, 0.282-0.926; p = 0.027) and ORR (odds ratio, 4.694; p < 0.001). CONCLUSION. The presence of an enhanced rim on PVP MDCT is an independent predictor of survival and response to bevacizumab-based chemotherapy among patients with CRLM.

Radiologic Evaluation and Structured Reporting Form for Extrahepatic Bile Duct Cancer: 2019 Consensus Recommendations from the Korean Society of Abdominal Radiology

Radiologic imaging is important for evaluating extrahepatic bile duct (EHD) cancers; it is used for staging tumors and evaluating the suitability of surgical resection, as surgery may be contraindicated in some cases regardless of tumor stage. However, the published general recommendations for EHD cancer and recommendations guided by the perspectives of radiologists are limited. The Korean Society of Abdominal Radiology (KSAR) study group for EHD cancer developed key questions and corresponding recommendations for the radiologic evaluation of EHD cancer and organized them into 4 sections: nomenclature and definition, imaging technique, cancer evaluation, and tumor response. A structured reporting form was also developed to allow the progressive accumulation of standardized data, which will facilitate multicenter studies and contribute more evidence for the development of recommendations.