Diagnostic accuracy and sensitivity of diffusion-weighted and of gadoxetic acid-enhanced 3-T MR imaging alone or in combination in the detection of small liver metastasis (≤ 1.5 cm in diameter). Invest Radiol. 2012;47:159-166. [PMID: 22330426 DOI: 10.1097/rli.0b013e31823a1495]

Hypointense Findings on Hepatobiliary Phase MR Images

Hepatobiliary (HB) contrast agents are increasingly valuable diagnostic tools in MRI, offering a wider range of applications as their clinical use expands. Normal hepatocytes take up HB contrast agents, which are subsequently excreted in bile. This property creates a distinct HB phase providing valuable insights into liver function and biliary anatomy. HB contrast agents can assist in diagnosing a broad spectrum of HB diseases ranging from diffuse liver disease to focal hepatic lesions and can delineate anatomic details of the biliary tree. Understanding the pharmacodynamics of HB contrast agents is paramount to their appropriate clinical application and troubleshooting. HB phase hypointensity can arise from various diffuse and focal abnormalities that may or may not be associated with biliary excretion. Hypointensity during the HB phase can be broadly grouped into diffuse hypointensity, regional hypointensity, and focal lesions for better evaluation of the underlying cause. Abnormalities may arise from hepatic parenchymal, biliary, or vascular causes, or a combination thereof in each of the broad groups. Recognition of a suboptimal hypointense HB phase is important in the evaluation of focal lesions in patients with cirrhosis of the liver and particularly in those with hepatocellular carcinoma. Furthermore, hypointensity can also suggest the aggressiveness of malignancies such as hepatocellular carcinoma or colorectal metastases, which may affect the prognosis. It is essential to consider all imaging findings relative to the clinical context and the complete set of the MRI sequences performed for diagnosis of liver abnormalities. This comprehensive approach minimizes the risk of misinterpretation or pitfalls. The authors aim to equip radiologists with key insights for accurately understanding hypointensity in the HB phase, ultimately leading to more accurate diagnoses. ©RSNA, 2025 Supplemental material is available for this article.

Comparison of adaptive imaging receiver coil and traditional coil for multiplexed sensitivity encoding diffusion-weighted imaging of the liver

OBJECTIVES

To compare the image quality and efficacy of the adaptive imaging receiver (AIR) coil (GE Healthcare) and the traditional coil for multiplexed sensitivity encoding diffusion-weighted imaging (MUSE-DWI) in the detection of focal liver lesions (FLLs).

METHODS

Two groups of MUSE-DWI were obtained. Image quality was qualitatively evaluated by 3 independent blinded radiologists on a 5-point scale, and quantitative parameters were calculated by measurements of the region of interest in the liver and FLLs. McNemar's test were used to compare the characteristics and detectability.

RESULTS

Less image noise, sharper contours, milder susceptibility artefacts, and better liver lesion conspicuity were found by all radiologists in 60 livers with 140 FLLs with the AIR coil than with the traditional coil (reader average mean, 4.3-4.4 vs. 3.7-4.0, P < .001). The signal-to-noise ratio (SNR) of the liver was significantly higher with the AIR coil than with the traditional coil (right lobe: mean, 8.89 vs.7.76, P < .05; left lobe: mean, 7.14 vs.6.19, P < .001), and the SNR of FLLs (mean, 24.62 vs. 21.01, P < .001) and lesion-to-liver CNR (mean, 16.61 vs. 14.02, P < .001) exhibited significant differences between the AIR coil and the traditional coil. Besides, superior detection of FLLs was observed with the AIR coil compared to the traditional coil (95.7% [134/140] vs. 85.7% [120/140], P < .001).

CONCLUSIONS

The AIR coil yields less noise, fewer distortions, better lesion detectability, higher SNR of the liver and FLLs, and improved lesion-to-liver CNR during liver MUSE-DWI. Thus, it is a feasible and effective scanning scheme in liver MRI.

ADVANCES IN KNOWLEDGE

The AIR coil improves SNR and the quality of liver MR imaging compared with the traditional coil.

Analysis of endoscopic and pathological features of 6961 cases of gastric cancer

Gastric cancer (GC) stage and tissue differentiation affect treatment efficacy and prognosis, highlighting the importance of understanding the risk factors that affect these parameters. Therefore, this study analyzed risk factors affecting the GC stage and differentiation and the relationships between the cancer site and the sex and age of the patient. We collected clinical data from 6961 patients with GC, including sex, age, endoscopic lesion location, and pathological differentiation. Patients were grouped based on GC stage (early or advanced), differentiation (well or poorly differentiated), and lesion site (upper stomach [cardia and fundus], middle stomach [gastric body], and lower stomach [gastric antrum]). Differences in sex, age, location, stage, and degree of differentiation were assessed based on these groupings. Univariate analysis revealed that the disease location and differentiation significantly differed based on the GC stage (P < 0.05), whereas sex, age, site, and stage significantly differed based on GC differentiation (P < 0.05). A multivariate analysis confirmed these factors as independent risk factors affecting GC. Moreover, lesion sites significantly differed between sexes (P < 0.05) and among age groups (P < 0.05). Although the effects of family history, lifestyle, and Helicobacter pylori infection status of the patients were not considered, this single-center retrospective study established independent risk factors for GC.Trial registration ChiCTR2200061989.

The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of gastric cancer, 2023

The 2023 update of the Chinese Society of Clinical Oncology (CSCO) Clinical Guidelines for Gastric Cancer focuses on standardizing cancer diagnosis and treatment in China, reflecting the latest advancements in evidence-based medicine, healthcare resource availability, and precision medicine. These updates address the differences in epidemiological characteristics, clinicopathological features, tumor biology, treatment patterns, and drug selections between Eastern and Western gastric cancer patients. Key revisions include a structured template for imaging diagnosis reports, updated standards for molecular marker testing in pathological diagnosis, and an elevated recommendation for neoadjuvant chemotherapy in stage III gastric cancer. For advanced metastatic gastric cancer, the guidelines introduce new recommendations for immunotherapy, anti-angiogenic therapy and targeted drugs, along with updated management strategies for human epidermal growth factor receptor 2 (HER2)-positive and deficient DNA mismatch repair (dMMR)/microsatellite instability-high (MSI-H) patients. Additionally, the guidelines offer detailed screening recommendations for hereditary gastric cancer and an appendix listing drug treatment regimens for various stages of gastric cancer. The 2023 CSCO Clinical Guidelines for Gastric Cancer updates are based on both Chinese and international clinical research and expert consensus to enhance their applicability and relevance in clinical practice, particularly in the heterogeneous healthcare landscape of China, while maintaining a commitment to scientific rigor, impartiality, and timely revisions.

Gadoxetic acid in hepatocellular carcinoma and liver metastases: pearls and pitfalls

Gadoxetic disodium (Primovist) is a hepatocyte-specific magnetic resonance imaging (MRI) contrast agent with increasing popularity with its unique dual dynamic and excretory properties in focal liver lesion detection and characterisation. In-depth knowledge of its diagnostic utility and pitfalls in hepatocellular carcinoma (HCC) and liver metastases is crucial in facilitating clinical management. The current article reviews the pearls and pitfalls in these aspects with highlights from the latest research evidence. Pearls for common usage of Primovist in HCC includes detection of precursor cancer lesions in cirrhotic patients. Hepatobiliary phase hypointensity precedes arterial phase hyperenhancement (APHE) in hepatocarcinogenesis. Hepatobiliary phase hypointense nodules without APHE can represent early or progressed hepatocellular carcinoma (HCC) and high-grade dysplastic nodules. In addition, Primovist is useful to differentiate HCC from pseudolesions. Pitfalls in diagnosing HCC include transient tachypnoea in the arterial phase, rare hepatobiliary phase hyperintense HCC, and decompensated liver cirrhosis compromising image quality. Primovist is currently the most sensitive technique in diagnosing liver metastases before curative hepatic resection. Other patterns of enhancement of liver metastases, "disappearing" liver metastases are important pitfalls. Radiologists should be aware of the diagnostic utility, limitations, and potential pitfalls for the common usage of hepatobiliary specific contrast agent in liver MRI.

Diagnostic Performance of Contrast Enhanced CT Alone or in Combination with (Non-)Enhanced MRI for Colorectal Liver Metastasis

RATIONALE AND OBJECTIVES

To compare the diagnostic performance of contrast enhanced CT (CE-CT), CE-CT combined with non-enhanced MRI (NE-MRI) or contrast enhanced MRI (CE-MRI) for colorectal liver metastasis (CRLM).

MATERIALS AND METHODS

Sixty-six colorectal cancer patients with 198 focal liver lesions who underwent preoperative abdominal CE-CT and MRI examinations were included respectively. The images were assessed independently by two readers in three protocols (1: CE-CT, 2: CE-CT+NE-MRI, 3: CE-CT+CE-MRI). The diagnostic performance of each protocol was analyzed by receiver operating characteristic (ROC) curve and the areas under ROC (AUCs) were calculated and compared.

RESULTS

The detection rates of protocol 2 were 90.9%-92.9% for liver lesions and 86.4%-89.6% for CRLM, and both significantly higher than protocol 1 of 82.8%-85.4% and 76.8%-80.8% (p<0.001-0.001), whereas similar to protocol 3 of 91.9%-94.4% and 87.2%-91.2% (p 0.250-1.000). The AUCs of protocol 2 were greater than protocol 1 for all lesions (0.914-0.934 vs. 0.779-0.799, p<0.001) and lesions < 10mm (0.726-0.776 vs. 0.528-0.561, p<0.001), and were not inferior to that of protocol 3 (0.929-0.949 in all lesions and 0.754-0.821 in lesion < 10mm, p 0.053-0.162).

CONCLUSION

CE-CT combined with NE-MRI offered superior diagnostic performance for CRLM compared to CE-CT alone and showed comparable performance to CE-CT combined with CE-MRI.

Exploring the Outcome of Disappearance or Small Remnants of Colorectal Liver Metastases during First-Line Chemotherapy on Hepatobiliary Contrast-Enhanced and Diffusion-Weighted MR Imaging

We aimed to evaluate the outcome of the disappearance or small remnants of colorectal liver metastases during first-line chemotherapy assessed by hepatobiliary contrast-enhanced and diffusion-weighted MR imaging (DW-MRI). Consecutive patients with at least one disappearing liver metastasis (DLM) or small residual liver metastases (≤10 mm) assessed by hepatobiliary contrast-enhanced and DW-MRI during first-line chemotherapy were included. Liver lesions were categorized into three groups: DLM; residual tiny liver metastases (RTLM) when ≤5 mm; small residual liver metastases (SRLM) when >5mm and ≤10 mm. The outcome of resected liver metastases was assessed in terms of pathological response, whereas lesions left in situ were evaluated in terms of local relapse or progression. Fifty-two outpatients with 265 liver lesions were radiologically reviewed; 185 metastases fulfilled the inclusion criteria: 40 DLM, 82 RTLM and 60 SRLM. We observed a pCR rate of 75% (3/4) in resected DLM and 33% (12/36) of local relapse for DLM left in situ. We observed a risk of relapse of 29% and 57% for RTLM and SRLM left in situ, respectively, and a pCR rate of about 40% overall for resected lesions. DLM assessed via hepatobiliary contrast-enhanced and DW-MRI very probably indicates a complete response. The surgical removal of small remnants of liver metastases should always be advocated whenever technically possible.

Application of nanotechnology in the early diagnosis and comprehensive treatment of gastrointestinal cancer

Gastrointestinal cancer (GIC) is a common malignant tumour of the digestive system that seriously threatens human health. Due to the unique organ structure of the gastrointestinal tract, endoscopic and MRI diagnoses of GIC in the clinic share the problem of low sensitivity. The ineffectiveness of drugs and high recurrence rates in surgical and drug therapies are the main factors that impact the curative effect in GIC patients. Therefore, there is an urgent need to improve diagnostic accuracies and treatment efficiencies. Nanotechnology is widely used in the diagnosis and treatment of GIC by virtue of its unique size advantages and extensive modifiability. In the diagnosis and treatment of clinical GIC, surface-enhanced Raman scattering (SERS) nanoparticles, electrochemical nanobiosensors and magnetic nanoparticles, intraoperative imaging nanoparticles, drug delivery systems and other multifunctional nanoparticles have successfully improved the diagnosis and treatment of GIC. It is important to further improve the coordinated development of nanotechnology and GIC diagnosis and treatment. Herein, starting from the clinical diagnosis and treatment of GIC, this review summarizes which nanotechnologies have been applied in clinical diagnosis and treatment of GIC in recent years, and which cannot be applied in clinical practice. We also point out which challenges must be overcome by nanotechnology in the development of the clinical diagnosis and treatment of GIC and discuss how to quickly and safely combine the latest nanotechnology developed in the laboratory with clinical applications. Finally, we hope that this review can provide valuable reference information for researchers who are conducting cross-research on GIC and nanotechnology.

Fast T2-weighted liver MRI: Image quality and solid focal lesions conspicuity using a deep learning accelerated single breath-hold HASTE fat-suppressed sequence

PURPOSE

Acceleration of MRI acquisitions and especially of T2-weighted sequences is essential to reduce the duration of MRI examinations but also kinetic artifacts in liver imaging. The purpose of this study was to compare the acquisition time and the image quality of a single-shot fat-suppressed turbo spin-echo (TSE) T2-weighted sequence with deep learning reconstruction (HASTE_DL) with that of a fat-suppressed T2-weighted BLADE TSE sequence in patients with focal liver lesions.

MATERIALS AND METHODS

Ninety-five patients (52 men, 43 women; mean age: 61 ± 14 [SD]; age range: 28-87 years) with 42 focal liver lesions (17 hepatocellular carcinomas, 10 sarcoidosis lesions, 9 myeloma lesions, 3 liver metastases and 3 focal nodular hyperplasias) who underwent liver MRI at 1.5 T including HASTE_DL and BLADE sequences were retrospectively included. Overall image quality, noise level in the liver, lesion conspicuity and sharpness of liver lesion contours were assessed by two independent readers. Liver signal-to-noise ratio (SNR) and lesion contrast-to-noise ratio (CNR) were measured and compared between the two sequences, as well as the mean duration of the sequences (Student t-test or Wilcoxon test for paired data).

RESULTS

Median overall quality on HASTE_DL images (3; IQR: 3, 3) was significantly greater than that on BLADE images (2; IQR: 1, 3) (P < 0.001). Median noise level in the liver on HASTE_DL images (0; IQR: 0, 0.5) was significantly lower than that on BLADE images (1; IQR: 1, 2) (P < 0.001). On HASTE_DL images, mean liver SNR (107.3 ± 39.7 [SD]) and mean focal liver lesion CNR (87.0 ± 76.6 [SD]) were significantly greater than those on BLADE images (67.1 ± 23.8 [SD], P < 0.001 and 48.6 ± 43.9 [SD], P = 0.027, respectively). Acquisition time was significantly shorter with the HASTE_DL sequence (18 ± [0] s; range: 18-18 s) compared to BLADE sequence (152 ± 47 [SD] s; range: 87-263 s) (P < 0.001).

CONCLUSION

By comparison with the BLADE sequence, HASTE_DL sequence significantly reduces acquisition time while improving image quality, liver SNR and focal liver lesions CNR.

Imaging of Oligometastatic Disease

Simple Summary

The imaging of oligometastatic disease (OMD) is challenging as it requires precise loco-regional staging and whole-body assessment. The combination of imaging modalities is often required. The more accurate imaging tool will be selected according to tumor type, the timing with regard to measurement and treatment, metastatic location, and the patient’s individual risk for metastasis. The most commonly used modalities are contrast-enhanced computed tomography (CT), magnetic resonance imaging and metabolic and receptor-specific imaging, particularly, ¹⁸F-fluorodesoxyglucose positron emission tomography/CT, used alone or in combination.

Abstract

Oligometastatic disease (OMD) is an emerging state of disease with limited metastatic tumor burden. It should be distinguished from polymetastatic disease due the potential curative therapeutic options of OMD. Imaging plays a pivotal role in the diagnosis and follow-up of patients with OMD. The imaging tools needed in the case of OMD will differ according to different parameters, which include primary tumor type, timing between measurement and treatment, potential metastatic location and the patient’s individual risk for metastasis. In this article, OMD is defined and the use of different imaging modalities in several oncologic situations are described in order to better understand OMD and its specific implication for radiologists.

Total Bilirubin Level as a Predictor of Suboptimal Image Quality of the Hepatobiliary Phase of Gadoxetic Acid-Enhanced MRI in Patients with Extrahepatic Bile Duct Cancer

Objective

This study aimed to determine a factor for predicting suboptimal image quality of the hepatobiliary phase (HBP) of gadoxetic acid-enhanced MRI in patients with extrahepatic bile duct (EHD) cancer before MRI examination.

Materials and Methods

We retrospectively evaluated 259 patients (mean age ± standard deviation: 68.0 ± 8.3 years; 162 male and 97 female) with EHD cancer who underwent gadoxetic acid-enhanced MRI between 2011 and 2017. Patients were divided into a primary analysis set (n = 184) and a validation set (n = 75) based on the diagnosis date of January 2014. Two reviewers assigned the functional liver imaging score (FLIS) to reflect the HBP image quality. The FLIS consists of the sum of three HBP features, each scored on a 0–2 scale: liver parenchymal enhancement, biliary excretion, and signal intensity of the portal vein. Patients were classified into low-FLIS (0–3) or high-FLIS (4–6) groups. Multivariable analysis was performed to determine a predictor of low FLIS using serum biochemical and imaging parameters of cholestasis severity. The optimal cutoff value for predicting low FLIS was obtained using receiver operating characteristic analysis, and validation was performed.

Results

Of the 259 patients, 140 (54.0%) and 119 (46.0%) were classified into the low-FLIS and high-FLIS groups, respectively. In the primary analysis set, total bilirubin was an independent factor associated with low FLIS (adjusted odds ratio per 1-mg/dL increase, 1.62; 95% confidence interval [CI], 1.32–1.98). The optimal cutoff value of total bilirubin for predicting low FLIS was 2.1 mg/dL with a sensitivity of 95.1% (95% CI: 88.9–98.4) and a specificity of 89.0% (95% CI: 80.2–94.9). In the validation set, the total bilirubin cutoff showed a sensitivity of 92.1% (95% CI: 78.6–98.3) and a specificity of 83.8% (95% CI: 68.0–93.8).

Conclusion

Serum total bilirubin before acquisition of gadoxetic acid-enhanced MRI may help predict suboptimal HBP image quality in patients with EHD cancer.

Compressed sensing for breath-hold high-resolution hepatobiliary phase imaging: image noise, artifact, biliary anatomy evaluation, and focal lesion detection in comparison with parallel imaging

PURPOSE

To assess image quality, performance for biliary anatomy diagnosis, and focal lesion detection rate of breath-hold high-resolution 3D T1-weighted hepatobiliary phase imaging using compressed sensing (CS HBP) compared to standard HBP using conventional parallel imaging.

METHODS

This retrospective study assessed consecutive 125 patients who underwent CS HBP and standard HBP between November 2019 and July 2020. Optimized resolution and scan time for CS HBP were 1 × 1.4 × 1 mm³ and 15 s, while those for standard HBP were 1.3 × 1.8 × 3 mm³ and 16 s. Two independent radiologists evaluated qualitative indices on the clarity of liver margin, visibility of the hepatic vessel and bile duct, image noise, and artifact on a 5-point scale. Biliary anatomy, confidence for biliary anatomy diagnosis, expected number of bile duct openings, and number of focal lesions were assessed. Wilcoxon signed-rank test, Pearson chi-square test, and sensitivity for focal lesion were used for statistical analysis. Intraclass correlation coefficient (ICC) and Cohen's kappa (κ) were used to determine inter-observer agreement.

RESULTS

CS HBP showed significantly better liver edge sharpness and bile duct visualization, but greater subjective image noise and non-respiratory artifacts compared to standard HBP. CS HBP showed higher number of concordantly assigned biliary anatomy across readers (86 vs. 80), indicating greater inter-observer agreement for biliary anatomy (κ, 0.67 vs. 0.45) and the number of bile duct openings (ICC, 0.860 vs. 0.579) with significantly higher diagnostic confidence (4.70-4.74 vs. 3.96-4.55; p = 0.002). Both readers identified more focal lesions in CS HBP than in standard HBP (88.2% and 84.5% vs. 66.3% and 73.4%).

CONCLUSION

Breath-hold high-resolution CS HBP was a feasible clinical sequence providing superior liver edge sharpness, bile duct visualization, and focal lesion detection rate compared to standard HBP despite higher noise and artifact. Due to improved spatial resolution, CS HBP yielded a higher inter-observer agreement and confidence for the biliary anatomy diagnosis.

The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of gastric cancer, 2021

There exist differences in the epidemiological characteristics, clinicopathological features, tumor biological characteristics, treatment patterns, and drug selections between gastric cancer patients from the Eastern and Western countries. The Chinese Society of Clinical Oncology (CSCO) has organized a panel of senior experts specializing in all sub-specialties of gastric cancer to compile a clinical guideline for the diagnosis and treatment of gastric cancer since 2016 and renews it annually. Taking into account regional differences, giving full consideration to the accessibility of diagnosis and treatment resources, these experts have conducted expert consensus judgment on relevant evidence and made various grades of recommendations for the clinical diagnosis and treatment of gastric cancer to reflect the value of cancer treatment and meeting health economic indexes in China. The 2021 CSCO Clinical Practice Guidelines for Gastric Cancer covers the diagnosis, treatment, follow-up, and screening of gastric cancer. Based on the 2020 version of the CSCO Chinese Gastric Cancer guidelines, this updated guideline integrates the results of major clinical studies from China and overseas for the past year, focused on the inclusion of research data from the Chinese population for more personalized and clinically relevant recommendations. For the comprehensive treatment of non-metastatic gastric cancer, attentions were paid to neoadjuvant treatment. The value of perioperative chemotherapy is gradually becoming clearer and its recommendation level has been updated. For the comprehensive treatment of metastatic gastric cancer, recommendations for immunotherapy were included, and immune checkpoint inhibitors from third-line to the first-line of treatment for different patient groups with detailed notes are provided.

Spectrum of liver lesions hyperintense on hepatobiliary phase: an approach by clinical setting

Hepatobiliary MRI contrast agents are increasingly being used for liver imaging. In clinical practice, most focal liver lesions do not uptake hepatobiliary contrast agents. Less commonly, hepatic lesions may show variable signal characteristics on hepatobiliary phase. This pictorial essay reviews a broad spectrum of benign and malignant focal hepatic observations that may show hyperintensity on hepatobiliary phase in various clinical settings. In non-cirrhotic patients, focal hepatic observations that show hyperintensity in the hepatobiliary phase are usually benign and typically include focal nodular hyperplasia. In patients with primary or secondary vascular disorders, focal nodular hyperplasia-like lesions arise as a local hyperplastic response to vascular alterations and tend to be iso- or hyperintense in the hepatobiliary phase. In oncologic patients, metastases and cholangiocarcinoma are hypointense lesions in the hepatobiliary phase; however, occasionally they may show a diffuse, central and inhomogeneous hepatobiliary paradoxical uptake with peripheral rim hypointensity. Post-chemotherapy focal nodular hyperplasia-like lesions may be tricky, and their typical hyperintense rim in the hepatobiliary phase is very helpful for the differential diagnosis with metastases. In cirrhotic patients, hepatocellular carcinoma may occasionally appear hyperintense on hepatobiliary phase.

Value of gadoxetic acid-enhanced MR imaging and DWI in classification, characterization and confidence in diagnosis of solid focal liver lesions

OBJECTIVE

To assess gadoxetic acid (Gd-EOB-DTPA) and diffusion-weighted imaging (DWI) value in classification (benign vs. malignant) and characterization of solid focal liver lesions (SFLLs) and impact on confidence in diagnosis.

METHODS

A total of 195 lesions (46 hepatocellular carcinomas [HCCs], 45 metastases, 32 adenomas, 37 focal nodular hyperplasias [FNHs] and 35 hemangiomas) were retrospectively evaluated in 93 patients. Three imaging datasets were compared: DWI/ apparent diffusion coefficient (ADC) (set A), Gd-EOB-DTPA (set B) and combination of both (set C). Two radiologists (R) independently classified (on a five-point ordinal scale) and characterized each lesion. The accuracy in classification and characterization was compared, and the diagnostic confidence was assessed.

RESULTS

The classification accuracy on set A, B and C was 86.2%, 91.3% and 91.8% (R1), and 84.6%, 91.8% and 93.3% (R2); and characterization accuracy was 67.2%, 88.2% and 87.7% (R1), and 60.5%, 88.2% and 85.6% (R2). Classification by reader 1 showed no significant difference between set A and B (p=.09). For both readers, there was a significant difference between set A and C in both classification and characterization (all p < .05), but no significant difference between set B and C in neither classification nor characterization. No significant difference between the three datasets in classification and characterization of hemangiomas (all p > .05). The diagnostic confidence of the readers has increased progressively from set A to Set C (all p < .01).

CONCLUSIONS

DWI may suggest benignity or malignancy of solid liver lesions, while Gd-EOB-DTPA-enhanced imaging remains superior in lesions characterization and the combination of both increases the diagnostic confidence. DWI is very helpful in the diagnosis of hepatic hemangiomas.

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.

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.

The combination of hepatobiliary phase with Gd-EOB-DTPA and DWI is highly accurate for the detection and characterization of liver metastases from neuroendocrine tumor

OBJECTIVES

To compare the diagnostic accuracy of dynamic contrast-enhanced phases, hepatobiliary phase (HBP), and diffusion-weighted imaging (DWI) for the detection of liver metastases from neuroendocrine tumor (NET).

METHODS

Sixty-seven patients with suspected NET liver metastases underwent gadoxetic acid-enhanced MRI. Three radiologists read four imaging sets separately and independently: DWI, T2W+dynamic, T2WI+HBP, and DWI+HBP. Reference standard included all imaging, histological findings, and clinical data. Sensitivity and specificity were calculated and compared for each imaging set. Interreader agreement was evaluated by intraclass correlation coefficient (ICC). Univariate logistic regression was performed to evaluate lesion characteristics (size, ADC, and enhancing pattern) associated to false positive and negative lesions.

RESULTS

Six hundred twenty-five lesions (545 metastases, 80 benign lesions) were identified. Detection rate was significantly higher combining DWI+HBP than the other imaging sets (sensitivity 86% (95% confidence interval (CI) 0.845-0.878), specificity 94% (95% CI 0.901-0.961)). The sensitivity and specificity of the other sets were 82% and 65% for DWI, 88% and 69% for T2WI, and 90% and 82% for HBP+T2WI, respectively. The interreader agreement was statistically higher for both HBP sets (ICC = 0.96 (95% CI 0.94-0.97) for T2WI+HBP and ICC = 0.91 (95% CI 0.87-0.94) for DWI+HBP, respectively) compared with that for DWI (ICC = 0.76 (95% CI 0.66-0.83)) and T2+dynamic (ICC = 0.85 (95% CI 0.79-0.9)). High ADC values, large lesion size, and hypervascular pattern lowered the risk of false negative.

CONCLUSION

Given the high diagnostic accuracy of combining DWI+HBP, gadoxetic acid-enhanced MRI is to be considered in NET patients with suspected liver metastases. Fast MRI protocol using T2WI, DWI, and HBP is of interest in this population.

KEY POINTS

• The combined set of diffusion-weighted (DW) and hepatobiliary phase (HBP) images yields the highest sensitivity and specificity for neuroendocrine liver metastasis (NELM) detection. • Gadoxetic acid should be the contrast agent of choice for liver MRI in NET patients. • The combined set of HBP and DWI sequences could also be used as a tool of abbreviated MRI in follow-up or assessment of treatment such as somatostatin analogs.

Chinese consensus on the diagnosis and treatment of gastric cancer with liver metastases

Background

The incidence of gastric cancer with liver metastases (GCLM) is 9.9-18.7%, with a median survival time of 11 months and a 5-year survival rate <20%. Multidisciplinary treatment (MDT) is gradually gaining recognition as the most important method. However, specific treatment plans remain unclear. The aim of study was to provide a consensus to improve the diagnosis and treatment of GCLM.

Methods

We brought together experts from relevant medical fields across China, including the Chinese Research Hospital Association Digestive Tumor Committee, Chinese Association of Upper Gastrointestinal Surgeons, Chinese Gastric Cancer Association, and the Gastrointestinal Surgical Group of Chinese Surgical Society Affiliated to Chinese Medical Association, to discuss and formulate this consensus.

Results

A consensus was reached on the diagnosis and treatment of GCLM. Moreover, we have developed a new clinical classification system, the Chinese Type for Gastric Cancer Liver Metastases, based on the likelihood of a surgical treatment being successful.

Conclusions

The MDT mode should be implemented throughout all treatment of GCLM.A Chinese version of this expert consensus has been published in the Chinese Journal of Practical Surgery (Volume 39, Issue 10, p. 405-411). Written permission was obtained from the Chinese Journal of Practical Surgery to disseminate the expert consensus in English.

Diagnostic performance of contrast-enhanced ultrasound and magnetic resonance imaging for detecting colorectal liver metastases: A systematic review and meta-analysis

OBJECTIVES

To determine the diagnostic performance of contrast-enhanced ultrasound, diffusion-weighted magnetic resonance imaging and contrast-enhanced magnetic resonance imaging for detecting colorectal liver metastases.

METHODS

We performed comprehensive searches of the MEDLINE, EMBASE, and Cochrane Library databases to identify studies reporting the per-lesion diagnostic accuracy of contrast-enhanced ultrasound, diffusion-weighted magnetic resonance imaging, and contrast-enhanced magnetic resonance imaging for detecting colorectal liver metastases. Studies published between January 2003 and December 2018 with reference standards, including histopathology and intraoperative observation, and/or follow-up, were included. Sources of bias were assessed using the QUADAS-2 tool. A linear mixed-effects regression model was used to determine sensitivity estimates.

RESULTS

Overall, 47 articles were included. The sensitivity estimates for contrast-enhanced ultrasound, diffusion-weighted magnetic resonance imaging, and contrast-enhanced magnetic resonance imaging for detecting colorectal liver metastases were 85.3%, 83.0%, and 90.1%, respectively. For lesions ≥10 mm in diameter, the sensitivities were 93.1%, 92.9%, and 94.5%, respectively. In 21 articles using histopathology as the only reference standard, the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for contrast-enhanced ultrasound/contrast-enhanced magnetic resonance imaging were 86%/91%, 91%/95%, 9.2/16.6, 0.15/0.10, and 61/170, respectively.

CONCLUSIONS

CEUS showed a diagnostic ability comparable to that of DWI and CEMRI, particularly for lesions ≥10 mm in diameter.

Improving preoperative detection of synchronous liver metastases in pancreatic cancer with combined contrast-enhanced and diffusion-weighted MRI

PURPOSE

To explore the value of gadolinium-enhanced MRI combined with diffusion-weighted MRI (Gd-enhanced MRI with DWI) in addition to contrast-enhanced CT (CECT) for detection of synchronous liver metastases for potentially resectable pancreatic cancer.

METHODS

By means of a retrospective cohort study we included patients with potentially resectable pancreatic cancer on CECT, who underwent Gd-enhanced MRI with DWI between January 2012 and December 2016. A single observer evaluated MRI and CT and was blinded to imaging, pathology, and surgery reports. Liver lesions were scored in both modalities, using a 3-point scale: 1-benign, 2-indeterminate, 3- malignant (i.e., metastasis). The primary outcome parameters were the presence of liver metastases on Gd-enhanced MRI with DWI and the sensitivity of Gd-enhanced MRI with DWI for synchronous liver metastases.

RESULTS

We included 66 patients (42 men, 24 women; median age 65 years, range 36-82 years). In 19 patients, liver metastases were present, which were confirmed by histopathology (n = 12), ¹⁸FDG-PET (n = 6), or surgical inspection (n = 1). Gd-enhanced MRI with DWI showed metastases in 16/19 patients (24%), which resulted in a sensitivity of 84% (95% CI 60-97%). Contrast-enhanced MRI showed 156 and DWI 397 metastases (p = 0.051), and 339 were particularly small (< 5 mm).

CONCLUSIONS

In this study, Gd-enhanced MRI with DWI detected synchronous liver metastases in 24% of patients with potentially resectable pancreatic cancer on CECT with a sensitivity of 84%. Diffusion-weighted MRI showed a greater number of metastases than any other sequence, particularly small metastases (< 5 mm).

Non-contrast liver MRI as an alternative to gadoxetic acid-enhanced MRI for liver metastasis from colorectal cancer

BACKGROUND

Liver magnetic resonance imaging (MRI) provides reliable diagnostic performance for detecting liver metastasis but is costly and time-consuming.

PURPOSE

To compare the diagnostic performance of non-contrast liver MRI to whole MRI using gadoxetic acid for detecting liver metastasis in patients with colorectal cancer (CRC).

MATERIAL AND METHODS

We included 175 patients with histologically confirmed 401 liver metastases and 73 benign liver lesions. A non-contrast MRI (T1-weighted, T2-weighted, and diffusion-weighted images) with or without multidetector computed tomography (MDCT) and a whole MRI (gadoxetic acid-enhanced and non-contrast MRI) were analyzed independently by two observers to detect liver metastasis using receiver operating characteristic analysis.

RESULTS

We found no significant differences in Az value (range = 0.914-0.997), sensitivity (range = 95.2-99.6%), specificity (range = 77.3-100%), or positive (range = 92.9-100%) or negative predictive value (range = 87.5-95.7%) between the non-contrast MRI with or without MDCT and the whole MRI for both observers for all lesions as well as lesions ≤1.0 cm and lesions >1.0 cm in size ( P = 0.203-1.000). Combined MDCT and non-contrast MRI led to similar numbers of false-positive diagnosis to the whole MRI (eight for Observers 1 and 4 vs. 3 for Observer 2).

CONCLUSION

Non-contrast liver MRI may serve as an alternative to gadoxetic acid-enhanced MRI for detecting and characterizing liver metastasis from CRC, at least in patients with relatively high risk of liver metastasis who underwent MDCT. Non-contrast liver MRI could be beneficial especially for patients with lesions that are already documented as benign but require additional follow-up MRIs.

The Chinese Society of Clinical Oncology (CSCO): clinical guidelines for the diagnosis and treatment of gastric cancer

China is one of the countries with the highest incidence of gastric cancer. There are differences in epidemiological characteristics, clinicopathological features, tumor biological characteristics, treatment patterns, and drug selection between gastric cancer patients from the Eastern and Western countries. Non-Chinese guidelines cannot specifically reflect the diagnosis and treatment characteristics for the Chinese gastric cancer patients. The Chinese Society of Clinical Oncology (CSCO) arranged for a panel of senior experts specializing in all sub-specialties of gastric cancer to compile, discuss, and revise the guidelines on the diagnosis and treatment of gastric cancer based on the findings of evidence-based medicine in China and abroad. By referring to the opinions of industry experts, taking into account of regional differences, giving full consideration to the accessibility of diagnosis and treatment resources, these experts have conducted experts' consensus judgement on relevant evidence and made various grades of recommendations for the clinical diagnosis and treatment of gastric cancer to reflect the value of cancer treatment and meeting health economic indexes. This guideline uses tables and is complemented by explanatory and descriptive notes covering the diagnosis, comprehensive treatment, and follow-up visits for gastric cancer.

Gastroenteropancreatic Neuroendocrine Tumors

Neuroendocrine tumors (NETs) are heterogeneous malignancies arising from the diffuse neuroendocrine system. They frequently originate in the gastroenteropancreatic (GEP) tract and the bronchopulmonary tree, and their incidence has steadily increased in the last 3 decades. Fundamental biologic and genomic differences underlie the clinical heterogeneity of NETs, and distinct molecular features characterize NETs of different grades and different primary sites. Although surgery remains the cornerstone of treatment for localized tumors, systemic treatment options for patients with metastatic NETs have expanded considerably. Somatostatin analogs have demonstrated both antisecretory and antitumor efficacy. Peptide receptor radionuclide therapy with lutetium-177 dotatate (¹⁷⁷ Lu-DOTATATE) has been approved for advanced GEP-NETs. The antitumor activity of everolimus has been demonstrated across a wide spectrum of NETs, and the antiangiogenic agent sunitinib has been approved for pancreatic NETs (pNETs). Chemotherapy with temozolomide and capecitabine has recently demonstrated an unprecedented prolongation of progression-free survival in a randomized trial of pNETs. Multiple retrospective series have reported the efficacy of liver-directed therapies both for palliating symptoms of hormone excess and for controlling tumor growth. Telotristat, an oral inhibitor of tryptophan hydroxylase, has been shown to reduce diarrhea in patients with carcinoid syndrome. Defining the therapeutic algorithm and identifying biomarkers predictive of response to treatments are among the main priorities for the next decade of research in the NET field.

Value of hepatocellular phase imaging after intravenous gadoxetate disodium for assessing hepatic metastases from gastroenteropancreatic neuroendocrine tumors: comparison with other MRI pulse sequences and with extracellular agent

OBJECTIVE

To compare hepatocellular phase imaging after intravenous gadoxetate disodium with other MRI pulse sequences and with extracellular agent for assessing hepatic metastases from gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN).

MATERIALS AND METHODS

In this IRB-approved, HIPAA-compliant retrospective study, we included 30 patients (15 women, mean age: 58 years, range 44-77 years) with GEP-NEN metastatic to the liver, who underwent MRI with gadoxetate disodium. Six MRI sequences were reviewed by two radiologists to score tumor-liver interface (TLI) on a 5-point scale, to assess lesion detectability in different liver segments (divided into 3 zones/patient), and to measure lesion size. Contrast-to-noise ratio (CNR) was calculated on each sequence. In 19 patients, lesion size and CNR on dynamic imaging with gadopentetate dimeglumine was compared with hepatocellular phase. Wilcoxon signed-rank test was used to compare TLI scores, lesion size, and median CNR, using Bonferroni correction for multiple testing. Interobserver agreement for TLI was analyzed using Krippendorff's alpha, and for lesion size using concordance correlation coefficient (CCC) and mean relative difference.

RESULTS

Hepatocellular phase had the best TLI (mean TLI for reader 1 = 1.2, reader 2 = 1.3) compared to all other sequences (p < 0.0001) with excellent interobserver agreement (Krippendorff's alpha = 1.0), maximum lesion detectability (61/90 zones), highest interobserver agreement for lesion measurement (CCC 0.9875 and smallest mean relative difference - 1.567%), and highest median CNR (31.2, p < 0.008). Hepatocellular phase also had the highest CNR when compared with gadopentetate imaging.

CONCLUSION

Hepatocellular phase imaging offers significant advantages for assessment of hepatic metastasis in GEP-NEN, and should be routinely considered for follow-up of these patients.

CT-MRI LI-RADS v2017: A Comprehensive Guide for Beginners

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy and the second leading cause of cancer-related deceases worldwide. Early diagnosis is essential for correct management and improvement of prognosis. Proposed for the first time in 2011 and updated for the last time in 2017, the Liver Imaging-Reporting and Data System (LI-RADS) is a comprehensive system for standardized interpretation and reporting of computed tomography (CT) and magnetic resonance imaging (MRI) liver examinations, endorsed by the American College of Radiology to achieve congruence with HCC diagnostic criteria in at-risk populations. Understanding its algorithm is fundamental to correctly apply LI-RADS in clinical practice. In this pictorial review, we provide a guide for beginners, explaining LI-RADS indications, describing major and ancillary features and eventually elucidating the diagnostic algorithm with the use of some clinical examples.

Computed Diffusion Weighted Imaging of the Liver Using Extrapolation Technique in Patients Who Underwent Liver Transplantation With Hepatocellular Carcinomas: Initial Experience and Feasibility Study

OBJECTIVE

This study aimed to evaluate the feasibility and image quality of computed diffusion weighted imaging (DWI) of the liver in patients with hepatocellular carcinoma (HCC).

METHODS

Twenty-four patients who underwent liver transplantation with HCC were enrolled. Computed DWI was synthesized for b-values of 800 (cDWI800) and 1200 s/mm (cDWI1200) using directly acquired DWI with b-values of 0, 50, and 500 s/mm. Signal intensity of HCC, background liver, and contrast-to-noise ratio were evaluated for directly acquired DWI of 800 s/mm (dDWI800), cDWI800, and cDWI1200. Two radiologists evaluated the image quality for contrast between HCC and liver, suppression of background signal and T2 shine-through, and overall image quality.

RESULTS

cDWI1200 showed the lowest contrast-to-noise ratio. Qualitative scores for background suppression and decreased T2 shine-through were highest for cDWI1200. However, contrast between HCC and background liver was worst in cDWI1200.

CONCLUSIONS

In computed DWI of high b-values, contrast between HCC and background liver was very low.

ACR Appropriateness Criteria® Pretreatment Staging of Colorectal Cancer

Colorectal cancers are common tumors in the United States and appropriate imaging is essential to direct appropriate care. Staging and treatment differs between tumors arising in the colon versus the rectum. Local staging for colon cancer is less integral to directing therapy given radical resection is often standard. Surgical options for rectal carcinoma are more varied and rely on accurate assessment of the sphincter, circumferential resection margins, and peritoneal reflection. These important anatomic landmarks are best appreciated on high-resolution imaging with transrectal ultrasound or MRI. When metastatic disease is suspected, imaging modalities that provide a global view of the body, such as CT with contrast or PET/CT may be indicated. Rectal cancer often metastasizes to the liver and so MRI of the liver with and without contrast provides accurate staging for liver metastases. This article focuses on local and distant staging and reviews the appropriateness of different imaging for both variants. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Suspected Liver Metastases

Liver metastases are the most common malignant liver tumors. The accurate and early detection and characterization of liver lesions is the key to successful treatment strategies. Increasingly, surgical resection in combination with chemotherapy is effective in significantly improving survival if all metastases are successfully resected. MRI and multiphase CT are the primary imaging modalities in the assessment of liver metastasis, with the relative preference toward multiphase CT or MRI depending upon the clinical setting (ie, surveillance or presurgical planning). The optimization of imaging parameters is a vital factor in the success of either modality. PET/CT, intraoperative ultrasound are used to supplement CT and MRI. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases: is the differential diagnosis using diffusion-weighted MRI possible?

Background Intrahepatic mass-forming cholangiocellular carcinoma (IMC) is the second most common primary liver tumor. The differentiation between IMC and solitary hypovascular liver metastases (SHLM) represents a diagnostic challenge due to many overlapping magnetic resonance imaging (MRI) features. Purpose To determine the value of diffusion-weighted imaging (DWI) in addition to conventional MRI for the distinction between intrahepatic mass-forming cholangiocarcinoma and solitary hypovascular liver metastases. Material and Methods Fifty-three patients with pathologically proven IMC (n = 31) and SHLM (n = 22) who had undergone MRI and DWI before surgery or percutaneous biopsy were enrolled in this study. The following MRI features were analyzed: the size and shape of the lesion, presence of capsular retraction and segmental biliary dilatation, T2-weighted (T2W) signal intensity, the presence of target sign on DWI and enhancement pattern. Apparent diffusion coefficient (ADC) values were calculated for each lesion ( b = 800 s/mm²). Univariate and multivariate logistic regression analyses were used to identify significant differentiating features between IMCs and SHLMs. Results Univariate analysis revealed that following parameters favor diagnosis of IMCs over SHLMs: lobulating shape, heterogeneous T2W signal intensity, capsular retraction, segmental biliary dilatation, target sign on DWI and rim-like enhancement on arterial phase followed by progressive enhancement in delayed phases. ADC values measured in the periphery of the lesion were significantly lower in IMCs in comparison to SHLMs. Multivariate analysis revealed that target sign on DWI was the most significant predictor of IMCs. Conclusion Qualitative DWI analysis with target sign significantly improves diagnostic accuracy for differentiation among IMC and SHLM lesions.

Whole-body MRI including diffusion-weighted MRI compared with 5-HTP PET/CT in the detection of neuroendocrine tumors

AIM

We wanted to explore if whole-body magnetic resonance imaging (MRI) including diffusion-weighted (DW) and liver-specific contrast agent-enhanced imaging could be valuable in lesion detection of neuroendocrine tumors (NET). [11C]-5-Hydroxytryptophan positron emission tomography/computed tomography (5-HTP PET/CT) was used for comparison.

MATERIALS AND METHODS

Twenty-one patients with NET were investigated with whole-body MRI, including DW imaging (DWI) and contrast-enhanced imaging of the liver, and whole-body 5-HTP PET/CT. Seven additional patients underwent upper abdomen MRI including DWI, liver-specific contrast agent-enhanced imaging, and 5-HTP PET/CT.

RESULTS

There was a patient-based concordance of 61% and a lesion-based concordance of 53% between the modalities. MRI showed good concordance with PET in detecting bone metastases but was less sensitive in detecting metastases in mediastinal lymph nodes. MRI detected more liver metastases than 5-HTP PET/CT.

CONCLUSION

Whole-body MRI with DWI did not detect all NET lesions found with whole-body 5-HTP PET/CT. Our findings indicate that MRI of the liver including liver-specific contrast agent-enhanced imaging and DWI could be a useful complement to whole-body 5-HTP PET/CT.

MR visible localization device for radiographic-pathologic correlation of surgical specimens

PURPOSE

The detection of small parenchymal hepatic lesions identified by preoperative imaging remains a challenge for traditional pathologic methods in large specimens. We developed a magnetic resonance imaging (MRI) compatible localization device for imaging of surgical specimens aimed to improve identification and localization of hepatic lesions ex vivo.

MATERIALS AND METHODS

The device consists of two stationary and one removable MR-visible grids lined with silicone gel, creating an orthogonal 3D matrix for lesion localization. To test the device, five specimens of swine liver with a random number of lesions created by microwave ablation were imaged on a 3T MR scanner. Two readers independently evaluated lesion coordinates and size, which were then correlated with sectioning guided by MR imaging.

RESULTS

All lesions (n=38) were detected at/very close to the expected localization. Inter-reader agreement of lesion localization was almost perfect (0.92). The lesion size estimated by MRI matched macroscopic lesion size in cut specimen (±2mm) in 34 and 35, respectively, out of 38 lesions.

CONCLUSION

Use of this MR compatible device for ex vivo imaging proved feasible for detection and three-dimensional localization of liver lesions, and has potential to play an important role in the ex vivo examination of surgical specimens in which pathologic correlation is clinically important.

Diffusion-weighted imaging of the liver: Current applications

Diffusion-weighted imaging (DWI) of the liver can be performed using most commercially available machines and is currently accepted in routine sequence. This sequence has some potential as an imaging biomarker for fibrosis, tumor detection/characterization, and following/predicting therapy. To improve reliability including accuracy and reproducibility, researchers have validated this new technique in terms of image acquisition, data sampling, and analysis. The added value of DWI in contrast-enhanced magnetic resonance imaging was established in the detection of malignant liver lesions. However, some limitations remain in terms of lesion characterization and fibrosis detection. Furthermore, the methodologies of image acquisition and data analysis have been inconsistent. Therefore, researchers should make every effort to not only improve accuracy and reproducibility but also standardize imaging parameters.

An overview of imaging techniques for liver metastases management

Evaluation of liver metastases is one of the most common indications for liver imaging. Imaging plays a key role in the of assessment liver metastases. A variety of imaging techniques, including ultrasonography, computed tomography, MRI and PET combined with CT scan are available for diagnosis, planning treatment, and follow-up treatment response. In this paper, the authors present the role of imaging for the assessment of liver metastases and the contribution of each of the different imaging techniques for their evaluation and management. Following recent developments in the field of oncology, the authors also present the importance of imaging for the assessment of liver metastases response to therapy. Finally, future perspectives on imaging of liver metastases are presented.

Diagnostic performance of CT, MRI and PET/CT in patients with suspected colorectal liver metastases: the superiority of MRI

BACKGROUND

Meticulous imaging of colorectal liver metastases (CRLM) is mandatory to optimize outcome after liver resection. However, the detection of CRLM is still challenging.

PURPOSE

To evaluate prospectively if magnetic resonance imaging (MRI) with diffusion-weighted and Gd-EOB-DTPA-enhanced sequences had a better diagnostic performance for CRLM compared to computed tomography (CT) and fluorine-18 fluorodeoxyglucose positron emission tomography (PET/CT).

MATERIAL AND METHODS

Forty-six patients scheduled for resection of suspected CRLM were evaluated prospectively from September 2011 to January 2013. None of the patients had undergone previous treatment for their CRLM. Multiphase CT, liver MRI with diffusion-weighted and dynamic Gd-EOB-DTPA-enhanced sequences and low-dose PET/CT were performed. Two independent, blinded readers evaluated the examinations. The reference standard was histopathological confirmation (81/140 CRLM) or follow-up.

RESULTS

A total of 140 CRLM and 196 benign lesions were identified. On a per-lesion basis, MRI had the significantly highest sensitivity overall and for CRLM < 10 mm (P < 0.001). Overall sensitivity/specificity and PPV/NPV were 68%/94% and 89%/81% for CT, 90%/87% and 82%/93% for MRI, and 61%/99% and 97%/78% for PET/CT. For CRLM < 10 mm it was 16%/96% and 54%/80% for CT, 74%/88% and 64%/93% for MRI, and 9%/98% and 57%/79% for PET/CT.

CONCLUSION

MRI had the significantly highest sensitivity compared with CT and PET/CT, particularly for CRLM < 10 mm. Therefore, detection of CRLM should be based on MRI.

Liver-directed treatments for liver metastasis from gastric adenocarcinoma: comparison between liver resection and radiofrequency ablation

BACKGROUND

Although various liver-directed treatment modalities, such as liver resection and radiofrequency ablation (RFA), have been applied to treat liver metastases from gastric cancer, optimal management of them remains controversial. In patients with liver metastasis from gastric cancer, we investigated the short- and long-term outcomes of liver resection and RFA and analyzed factors influencing survival.

METHODS

A total of 98 gastric cancer patients with liver metastasis and no extrahepatic disease were treated by liver resection (n = 68) or RFA (n = 30). Short- and long-term outcomes were evaluated retrospectively for each of the liver-directed treatments.

RESULTS

Severe complication rates did not differ between liver resection (18 %) and RFA (10 %) (p = 0.333). Only one treatment-related mortality occurred in the liver resection group. No statistically significant difference in survival was noted between the treatment groups. Median overall survival after liver resection was 24 months, with 3-year overall and progression-free survival rates of 40.6 % and 30.4 %, respectively. Median overall survival after RFA was 23 months, with 3-year overall and progression-free survival rates of 43.0 % and 37.4 %, respectively. Only the size of the metastases was shown to be an independent prognostic factor for gastric cancer patients with liver metastasis.

CONCLUSIONS

In select patients with liver metastasis from gastric cancer, liver resection and RFA showed satisfactory and comparable short- and long-term results. Thus, systemic chemotherapy may not be the only therapeutic option for patients with liver metastasis, and possible liver-directed treatment options for such patients should be considered on an individual basis.

Fifty Years of Technological Innovation: Potential and Limitations of Current Technologies in Abdominal Magnetic Resonance Imaging and Computed Tomography

Magnetic resonance imaging (MRI) has become an important modality for the diagnosis of intra-abdominal pathology. Hardware and pulse sequence developments have made it possible to derive not only morphologic but also functional information related to organ perfusion (dynamic contrast-enhanced MRI), oxygen saturation (blood oxygen level dependent), tissue cellularity (diffusion-weighted imaging), and tissue composition (spectroscopy). These techniques enable a more specific assessment of pathologic lesions and organ functionality. Magnetic resonance imaging has thus transitioned from a purely morphologic examination to a modality from which image-based disease biomarkers can be derived. This fits well with several emerging trends in radiology, such as the need to accurately assess response to costly treatment strategies and the need to improve lesion characterization to potentially avoid biopsy. Meanwhile, the cost-effectiveness, availability, and robustness of computed tomography (CT) ensure its place as the current workhorse for clinical imaging. Although the lower soft tissue contrast of CT relative to MRI is a long-standing limitation, other disadvantages such as ionizing radiation exposure have become a matter of public concern. Nevertheless, recent technical developments such as dual-energy CT or dynamic volume perfusion CT also provide more functional imaging beyond morphology.The aim of this article was to review and discuss the most important recent technical developments in abdominal MRI and state-of-the-art CT, with an eye toward the future, providing examples of their clinical utility for the evaluation of hepatic and renal pathologies.

Clinical Intravoxel Incoherent Motion and Diffusion MR Imaging: Past, Present, and Future

The concept of diffusion magnetic resonance (MR) imaging emerged in the mid-1980s, together with the first images of water diffusion in the human brain, as a way to probe tissue structure at a microscopic scale, although the images were acquired at a millimetric scale. Since then, diffusion MR imaging has become a pillar of modern clinical imaging. Diffusion MR imaging has mainly been used to investigate neurologic disorders. A dramatic application of diffusion MR imaging has been acute brain ischemia, providing patients with the opportunity to receive suitable treatment at a stage when brain tissue might still be salvageable, thus avoiding terrible handicaps. On the other hand, it was found that water diffusion is anisotropic in white matter, because axon membranes limit molecular movement perpendicularly to the nerve fibers. This feature can be exploited to produce stunning maps of the orientation in space of the white matter tracts and brain connections in just a few minutes. Diffusion MR imaging is now also rapidly expanding in oncology, for the detection of malignant lesions and metastases, as well as monitoring. Water diffusion is usually largely decreased in malignant tissues, and body diffusion MR imaging, which does not require any tracer injection, is rapidly becoming a modality of choice to detect, characterize, or even stage malignant lesions, especially for breast or prostate cancer. After a brief summary of the key methodological concepts beyond diffusion MR imaging, this article will give a review of the clinical literature, mainly focusing on current outstanding issues, followed by some innovative proposals for future improvements.

A meta-analysis of diffusion-weighted and gadoxetic acid-enhanced MR imaging for the detection of liver metastases

OBJECTIVES

To obtain the diagnostic performance of diffusion-weighted (DW) and gadoxetic-enhanced magnetic resonance (MR) imaging in the detection of liver metastases.

METHODS

A comprehensive search (EMBASE, PubMed, Cochrane) was performed to identify relevant articles up to June 2015. Inclusion criteria were: liver metastases, DW-MR imaging and/or gadoxetic acid-enhanced MR imaging, and per-lesion statistics. The reference standard was histopathology, intraoperative observation and/or follow-up. Sources of bias were assessed using the QUADAS-2 tool. A linear mixed-effect regression model was used to obtain sensitivity estimates.

RESULTS

Thirty-nine articles were included (1,989 patients, 3,854 metastases). Sensitivity estimates for DW-MR imaging, gadoxetic acid-enhanced MR imaging and the combined sequence for detecting liver metastases on a per-lesion basis was 87.1 %, 90.6 % and 95.5 %, respectively. Sensitivity estimates by gadoxetic acid-enhanced MR imaging and the combined sequence were significantly better than DW-MR imaging (p = 0.0001 and p < 0.0001, respectively), and the combined MR sequence was significantly more sensitive than gadoxetic acid-enhanced MR imaging (p < 0.0001). Similar results were observed in articles that compared the three techniques simultaneously, with only colorectal liver metastases and in liver metastases smaller than 1 cm.

CONCLUSIONS

In patients with liver metastases, combined DW-MR and gadoxetic acid-enhanced MR imaging has the highest sensitivity for detecting liver metastases on a per-lesion basis.

KEY POINTS

• DW-MRI is less sensitive than gadoxetic acid-enhanced MRI for detecting liver metastases • DW-MRI and gadoxetic acid-enhanced MRI is the best combination • Same results are observed in colorectal liver metastases • Same results are observed in liver metastases smaller than 1 cm • Same results are observed when histopathology alone is the reference standard.