Gadoxetic acid-enhanced MRI and diffusion-weighted imaging for the detection of colorectal liver metastases after neoadjuvant chemotherapy

Utility of abbreviated MRI in the post-treatment evaluation of rectal cancer

BACKGROUND

Post-treatment evaluation of patients with rectal cancer (RC) using magnetic resonance imaging (MRI) burdens medical resources, necessitating an exploration of abbreviated protocols.

PURPOSE

To evaluate the diagnostic performance of abbreviated MRI (A-MRI) for the post-treatment evaluation of RC patients.

MATERIAL AND METHODS

This retrospective study included RC patients who underwent non-contrast rectal MRI and standard liver MRI, as well as abdominal contrast-enhanced computed tomography (CECT) for post-treatment evaluation. A-MRI comprised diffusion-weighted imaging (DWI) and T2-weighted imaging of the upper abdomen and the pelvic cavity. Three radiologists independently reviewed A-MRI, CECT, and standard liver MRI in the detection of viable disease. The diagnostic performances were compared using a reference standard considering all available information, including pathology, FDG-PET, endoscopic results, and clinical follow-up.

RESULTS

We included 78 patients (50 men, 28 women; mean age=60.9 ± 10.2 years) and observed viable disease in 34 (43.6%). On a per-patient-basis analysis, A-MRI showed significantly higher sensitivity (95% vs. 81%, P = 0.04) and higher accuracy (93% vs. 82%, P < 0.01), compared to those of CECT, while A-MRI showed comparable sensitivity (91% vs. 91%, P = 0.42) and accuracy (97% vs. 98%, P = 0.06) to that of standard liver MRI. On a per-lesion-based analysis, A-MRI exhibited significantly superior lesion detectability than that of CECT (figure of merit 0.91 vs. 0.77, P < 0.01) and comparable to that of standard liver MRI (figure of merit 0.91 vs. 0.92, P = 0.75).

CONCLUSION

A-MRI exhibited higher sensitivity and diagnostic accuracy than those of CECT in the post-treatment evaluation of RC, while it showed comparable performances with standard liver MRI. A-MRI provides diagnostic added value in the follow-up of RC patients.

Contrast-Enhanced Ultrasound With SonoVue and Sonazoid for the Diagnosis of Colorectal Liver Metastasis After Chemotherapy

PURPOSE

To compare the diagnostic efficacy of SonoVue and Sonazoid contrast-enhanced ultrasound (CEUS) in correctly detecting and characterizing colorectal liver metastasis (CRLM) after chemotherapy.

MATERIALS AND METHODS

Patients with CRLMs treated with chemotherapy and subsequently scheduled for hepatic resection were prospectively enrolled from April 2020 to January 2021. Lesions detected by SonoVue or Sonazoid CEUS were recorded as and characterized as metastases or non-metastatic lesions respectively. Histopathology or intraoperative ultrasound with MRI were the reference standard.

RESULTS

A total of 348 focal liver lesions in 42 patients were investigated, including 297 CRLMs and 51 non-metastatic lesions. SonoVue showed significantly higher diagnostic accuracy (64.7% versus 54.0%; P < .001) and sensitivity (63.3% versus 50.5%; P < .001) in the diagnosis of CRLMs than Sonazoid, both methods presented with similar specificity (72.5% versus 74.5%; P = 1.0). Forty metastases appeared non-hypoenhancing (hyperenhancing or isoenhancing) in the late phase and postvascular phase of Sonazoid CEUS and were mischaracterized as benign lesions.

CONCLUSION

SonoVue performed significantly better than Sonazoid in the diagnosis of CRLMs after chemotherapy.

Improved sensitivity and positive predictive value of contrast-enhanced intraoperative ultrasound in colorectal cancer liver metastasis: a systematic review and meta-analysis

BACKGROUND

Surgery is an effective treatment for improving the survival rate of patients with colorectal cancer liver metastases (CRLM). However, accurately determining the resection margin of liver lesions during surgery remains challenging. Therefore, this study aimed to evaluate the sensitivity and predictive value of intraoperative contrast-enhanced ultrasound (CE-IOUS) in CRLM patients undergoing surgery.

METHODS

We performed a literature search of the PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang, and Weipu databases using the following search terms: metastatic liver cancer, colorectal cancer, sensitivity, contrast-enhanced intraoperative ultrasound, CE-IOUS, colorectal liver metastases, and CRLM. The search period was set from the date of establishment of the database to September 2021. Quality assessment of diagnostic accuracy studies 2 (QUADAS-2) recommended by the Cochrane Collaboration was used to assess the methodological quality of the included studies, and network meta-analysis was performed using Stata 15.0 software.

RESULTS

A total of 10 articles met the inclusion criteria. The meta-analysis results showed that the overall sensitivity and specificity of CE-IOUS were 0.96 [95% confidence interval (CI), 0.95-0.97] and 0.75 (95% CI, 0.70-0.80), respectively. The overall sensitivity and specificity of IOUS were 0.84 (95% CI, 0.82-0.86) and 0.82 (95% CI, 0.77-0.87), respectively. The area under the summary receiving operating characteristic (SROC) curves (AUCs) of CE-IOUS and IOUS were 0.9753 and 0.8590, respectively. The odds ratio (OR) and 95% CI of CE-IOUS changed the surgical margin were 0.205 and 0.071-0.465, P=0.000, the difference was statistically significant.

DISCUSSION

Based on the results of this meta-analysis, CE-IOUS improved the sensitivity and predictive value of CRLM detection compared with IOUS, and is more suitable for intraoperative planning of surgical margins. At present, it is the most sensitive imaging method available, and is recommended for use during liver resection to provide doctors with more reliable information during surgery.

Structured reporting of CT or MRI for perihilar cholangiocarcinoma: usefulness for clinical planning and interdisciplinary communication

PURPOSE

To compare the content and communication between the radiologist and the clinicians for treatment planning of structured reports (SRs) and narrative reports (NRs) for reporting CT/MRI findings in patients with perihilar cholangiocarcinoma.

MATERIALS AND METHOD

This retrospective study included 54 patients with perihilar cholangiocarcinoma who underwent CT/MRI before ERCP or surgery. For all patients, we generated both NRs and SRs for perihilar cholangiocarcinoma and compared the number of key features between NRs and SRs. In addition, three clinicians performed a questionnaire evaluation that included three questions regarding assessment of the sufficiency of information for surgical or procedural planning, the effort required for information extraction, and the report quality rated on a Likert scale.

RESULTS

SRs included significantly more predefined key features (6.89 ± 0.31) than NRs (5.87 ± 0.70) (p < 0.001). SRs provided greater sufficiency of information for clinical planning than NRs (89.9% vs. 18.5% of the cases, respectively; p < 0.001). Extraction of information was easier from SRs than NRs (94.4% vs. 9.3%, respectively) (p < 0.001). SRs received a higher overall report quality rating (5.96 ± 0.19) than NRs (4.31 ± 0.77) (p < 0.001).

CONCLUSIONS

SRs of CT/MRI findings for hilar cholangiocarcinoma can reveal more predefined key features, provide more sufficiency of information, and yield higher satisfaction levels, in comparison with NRs.

The impact of 18F-FDOPA-PET/MRI image fusion in detecting liver metastasis in patients with neuroendocrine tumors of the gastrointestinal tract

Background

This study assesses the value of image fusion using 18F-fluoro-L-DOPA (18F-DOPA) positron emission tomography (PET) and magnetic resonance imaging (MRI) for examining patients with neuroendocrine tumors (NETs) and a suspicion of metastasis of the liver.

Methods

Eleven patients (five women and six men aged between 20 and 81, with a mean age of 54.6 years) were included in the study. All patients underwent whole-body 18F-DOPA PET examinations and contrast-enhanced MRI with diffusion-weighted sequences (DWS). Image fusion was performed using a semiautomatic voxel-based algorithm. Images obtained using PET and MRI were assessed separately. Side-by-side evaluations of fused PET/MRI images were also performed.

Results

In total, 55 liver lesions (52 liver metastases and 3 benign lesions) were detected in the 11 patients. Sensitivity detection for liver lesions was higher when using PET/CT than when using contrast-enhanced MRI without DWSs and lower than using MRI with DWSs. The sensitivity of PET/MRI image fusion in the detection of liver metastasis was significantly higher than that of MRI with DWSs (P < 0.05).

Conclusion

Images of the liver obtained using PET and MRI in patients with NETs exhibited characteristic features. These findings suggest that an appropriate combination of available imaging modalities can optimize patient evaluations.

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.

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.

[Evaluation of Efficiencies on the Gadoxetic Acid-enhanced MRI for Preoperative Assessment of Liver Metastases from Colorectal Carcinoma]

THE AIMS OF OUR STUDY WERE

1) to evaluate efficiencies of gadoxetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI) for preoperative assessment of liver metastases from colorectal carcinoma, and 2) to compare them with other diagnostic imaging modalities. The subjects of the analysis were outpatients with advanced colorectal cancer who are at risk of developing liver metastases (initial setting: pre-test probability=20%). At initial setting, we performed a decision analysis to calculate numbers of true positive (TP), false negative (FN), false positive (FP) and true negative (TN) test results per 1000 patients of Gd-EOB-MRI and other imaging modalities (conventional contrast agent-enhanced MRI, contrast-enhanced CT and ¹⁸F-FDG PET/CT). From the result of decision analysis, we calculated the cost of detection per one patient with liver metastases (detection cost). Also, we calculated positive predictive value (PPV) and negative predictive value (NPV). Moreover, these values were defined as efficiencies in this study. In the initial setting, number of TP, FN, FP TN results and detection cost of Gd-EOB-MRI were 197, 3, 40, 760, and 224,032.8 Japanese Yen, respectively. Also, PPV and NPV were 83.1% and 99.7%, respectively. In comparison with other imaging modalities, efficiencies of Gd-EOB-MRI were superior to them, except detection cost. We consider that the efficiencies of Gd-EOB-MRI, which we had assessed are easy to understand and useful when they are used for explanation to patients.

Prospective comparison of gadoxetic acid-enhanced liver MRI and contrast-enhanced CT with histopathological correlation for preoperative detection of colorectal liver metastases following chemotherapy and potential impact on surgical plan

OBJECTIVE

To prospectively compare the diagnostic performance of gadoxetic acid-enhanced MRI (EOB-MRI) and contrast-enhanced CT (CECT) for preoperative detection of colorectal liver metastases (CRLM) following chemotherapy and to evaluate the potential change in the hepatic resection plan.

METHODS

51 patients with CRLM treated with preoperative chemotherapy underwent liver imaging by EOB-MRI and CECT prospectively. Two independent blinded readers characterized hepatic lesions on each imaging modality using a 5-point scoring system. 41 patients underwent hepatic resection and histopathological evaluation.

RESULTS

151 CRLM were confirmed by histology. EOB-MRI, compared to CECT, had significantly higher sensitivity in detection of CRLM ≤1.0 cm (86% vs. 45.5%; p < 0.001), significantly lower indeterminate lesions diagnosis (7% vs. 33%; p < 0.001) and significantly higher interobserver concordance rate in characterizing the lesions ≤1.0 cm (72% vs. 51%; p = 0.041). The higher yield of EOB-MRI could have changed the surgical plan in 45% of patients.

CONCLUSION

Following preoperative chemotherapy, EOB-MRI is superior to CECT in detection of small CRLM (≤1 cm) with significantly higher sensitivity and diagnostic confidence and interobserver concordance in lesion characterization. This improved diagnostic performance can alter the surgical plan in almost half of patients scheduled for liver resection.

Primary malignant tumours in the non-cirrhotic liver

Intrahepatic chlangiocarcinomas (CCs), the second most common primary malignant liver tumours, usually occur in non-cirrhotic liver, and can be classified into three types based on gross morphology: mass-forming; periductal infiltrating; and intraductal growing. Among them, mass-forming intrahepatic CCs are the most common type and characterized by homogeneous mass with an irregular but well-defined margin with peripheral enhancement on late arterial phase and delayed enhancement in central portion of tumours corresponding to the fibrous stroma. Several imaging features such as enhancement pattern and degree of diffusion restriction have been suggested as prognostic markers for mass-forming CCs. Hepatocellular carcinomas (HCCs) are the most common primary malignant liver tumors, and usually arise from the cirrhotic liver. However, approximately 20% of HCCs involve the non-cirrhotic liver (hereafter, non-cirrhotic HCC), and non-cirrhotic HCCs are often detected at an advanced stage due to the lack of surveillance for patients with non-cirrhotic liver. Other primary malignant liver tumours other than CCs and HCCs including angiosarcoma, undifferentiated embryonal sarcoma are quite rare, and imaging diagnosis is often difficult. This review offers a brief overview of epidemiology, risk factors and imaging features of primary malignant tumours in non-cirrhotic liver. Understanding of radiologic appearance and predisposing clinical features as well as differentials of primary malignant tumour in non-cirrhotic liver can be helpful for radiologists to adequately assess these tumours, and subsequently to make optimal management plan.

Detection and Viability of Colorectal Liver Metastases After Neoadjuvant Chemotherapy: A Multiparametric PET/CT-MRI Study

PURPOSE

The aim of this study was to compare combined gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)-enhanced and diffusion-weighted (DW) MRI with IV contrast-enhanced F-FDG PET/CT to detect and assess the viability of colorectal liver metastases (CLMs) after neoadjuvant chemotherapy (NAC).

PATIENTS AND METHODS

After NAC, 45 patients with CLMs were prospectively enrolled and underwent combined Gd-EOB-DTPA-enhanced and DW-MRI and contrast-enhanced F-FDG PET/CT. Forty patients subsequently underwent surgery based on intraoperative ultrasound, which served as the reference standard for the presence of CLMs. The number of metastases detected by each technique was then compared. In 69 resected metastases, the SUVmean and SUVmax, mean and maximum target-to-background ratio (TBR), total lesion glycolysis, metabolic tumor volume, and mean and minimum apparent diffusion coefficient (ADC) were examined to identify correlations with the corresponding tumor viability (TV) determined from histological specimens.

RESULTS

Intraoperative ultrasound revealed 153 CLMs, 122 of which were resected. The detection rate of MRI and contrast-enhanced F-FDG PET/CT were similar (P = 0.61). The SUVmax and minimum ADC were negatively correlated (r = -0.34, P = 0.005) on preoperative imaging after NAC. However, TV was significantly correlated with the maximum TBR (r = 0.33, P = 0.006) and mean TBR (r = 0.37, P = 0.002), but not with the minimum ADC (r = -0.02, P = 0.9) or mean ADC (r = 0.01, P = 0.9).

CONCLUSIONS

Combined Gd-EOB-DTPA-enhanced and DW-MRI and contrast-enhanced F-FDG PET/CT allow confident detection of CLMs, but only F-FDG PET metrics are associated with TV after NAC.

Intraoperative Contrast-Enhanced Ultrasound in Colorectal Liver Metastasis Surgery Improves the Identification and Characterization of Nodules

INTRODUCTION

The sensitivity of preoperative assessment of colorectal liver metastases (CRLM) ranges from 74 to 80%. Intraoperative ultrasound (IOUS) associated with contrast-enhanced intraoperative ultrasound (CE-IOUS) may be able to improve this. Thus, the aims of this study were to assess the value of IOUS and CE-IOUS for the surgical approach and to determine risk factors both for the detection of new nodules and for the modification of the surgical strategy.

MATERIALS AND METHODS

Forty-three patients who underwent CRLM surgery were included. These patients had an MRI in the 8 weeks preceding surgery and benefited from intraoperative IOUS and CE-IOUS.

RESULTS AND DISCUSSION

The use of IOUS/CE-IOUS permitted the identification of 43 additional lesions and an improved characterization of nodules in 23 patients with a resulting modification of surgical strategy. Lesions were down-staged in six patients and up-staged in six patients. Chemotherapy (p = 0.02) and the presence of nodules in the left lobe (p = 0.04) were predictive factors for finding new nodules at IOUS/CE-IOUS. The discovery of a new nodule systematically modified surgical management. IOUS/CE-IOUS improved intraoperative management of liver metastases. The techniques enable pertinent modification of surgical resections and a reduction of residual lesions.

Cost evaluation of gadoxetic acid-enhanced magnetic resonance imaging in the diagnosis of colorectal-cancer metastasis in the liver: Results from the VALUE Trial

OBJECTIVES

To assess the costs of diagnostic workup and surgery of three strategies for patients with colorectal cancer liver-metastases (CRCLM): gadoxetic-acid-enhanced MRI (Gd-EOB-DTPA-MRI), MRI with extracellular contrast-media (ECCM-MRI) or contrast-enhanced MDCT (CE-MDCT).

METHODS

The within-trial cost evaluation was modelled as a decision-tree to calculate the cost of diagnosis and surgery. The model used clinical outcomes and resource utilization data from a prospective randomized multicentre study. Analyses were performed for the 354-patient safety population from eight participating countries.

RESULTS

The diagnostic workup cost using Gd-EOB-DTPA-MRI upfront resulted in savings compared to ECCM-MRI in all countries except Thailand (difference <2 %). Compared to CE-MDCT, initial imaging with Gd-EOB-DTPA-MRI was less costly in all countries except Korea and Spain (differences 4 and 8 %, respectively). Significantly more patients in the Gd-EOB-DTPA-MRI group were eligible for surgery (39.3 % (48/122) vs. 31.0 % (36/116) and 26.7 % (31/116) for ECCM-MRI and CE-MDCT, respectively), allowing more patients to undergo potentially curative surgery, but resulting in higher treatment costs for the strategy starting with Gd-EOB-DTPA-MRI.

CONCLUSIONS

The benefits of Gd-EOB-DTPA-MRI due to less additional imaging and similar diagnostic workup costs in the three groups suggest that Gd-EOB-DTPA-MRI should be the preferred initial imaging procedure to evaluate hepatic resectability in patients with CRCLM.

KEY POINTS

• Diagnostic imaging cost to evaluate resectability was similar among the groups • Cost for imaging was rather small compared to the cost of surgery • Significantly more patients in the Gd-EOB-DTPA-MRI arm were eligible for surgery • Gd-EOB-DTPA-MRI is recommended for evaluating hepatic resectability in patients with CRCLM.

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.

Technical advancements and protocol optimization of diffusion-weighted imaging (DWI) in liver

An area of rapid advancement in abdominal MRI is diffusion-weighted imaging (DWI). By measuring diffusion properties of water molecules, DWI is capable of non-invasively probing tissue properties and physiology at cellular and macromolecular level. The integration of DWI as part of abdominal MRI exam allows better lesion characterization and therefore more accurate initial diagnosis and treatment monitoring. One of the most technical challenging, but also most useful abdominal DWI applications is in liver and therefore requires special attention and careful optimization. In this article, the latest technical developments of DWI and its liver applications are reviewed with the explanations of the technical principles, recommendations of the imaging parameters, and examples of clinical applications. More advanced DWI techniques, including Intra-Voxel Incoherent Motion (IVIM) diffusion imaging, anomalous diffusion imaging, and Diffusion Kurtosis Imaging (DKI) are discussed.