Gd-EOB-DTPA-Enhanced MRI for Detection of Liver Metastases from Colorectal Cancer: A Surgeon's Perspective!

Focal Liver Lesion MRI Feature Identification Using Efficientnet and MONAI: A Feasibility Study

Liver tumors constitute a major part of the global disease burden, often making regular imaging follow-up necessary. Recently, deep learning (DL) has increasingly been applied in this research area. How these methods could facilitate report writing is still a question, which our study aims to address by assessing multiple DL methods using the Medical Open Network for Artificial Intelligence (MONAI) framework, which may provide clinicians with preliminary information about a given liver lesion. For this purpose, we collected 2274 three-dimensional images of lesions, which we cropped from gadoxetate disodium enhanced T1w, native T1w, and T2w magnetic resonance imaging (MRI) scans. After we performed training and validation using 202 and 65 lesions, we selected the best performing model to predict features of lesions from our in-house test dataset containing 112 lesions. The model (EfficientNetB0) predicted 10 features in the test set with an average area under the receiver operating characteristic curve (standard deviation), sensitivity, specificity, negative predictive value, positive predictive value of 0.84 (0.1), 0.78 (0.14), 0.86 (0.08), 0.89 (0.08) and 0.71 (0.17), respectively. These results suggest that AI methods may assist less experienced residents or radiologists in liver MRI reporting of focal liver lesions.

Clinical added value of MRI to CT in patients scheduled for local therapy of colorectal liver metastases (CAMINO): study protocol for an international multicentre prospective diagnostic accuracy study

BACKGROUND

Abdominal computed tomography (CT) is the standard imaging method for patients with suspected colorectal liver metastases (CRLM) in the diagnostic workup for surgery or thermal ablation. Diffusion-weighted and gadoxetic-acid-enhanced magnetic resonance imaging (MRI) of the liver is increasingly used to improve the detection rate and characterization of liver lesions. MRI is superior in detection and characterization of CRLM as compared to CT. However, it is unknown how MRI actually impacts patient management. The primary aim of the CAMINO study is to evaluate whether MRI has sufficient clinical added value to be routinely added to CT in the staging of CRLM. The secondary objective is to identify subgroups who benefit the most from additional MRI.

METHODS

In this international multicentre prospective incremental diagnostic accuracy study, 298 patients with primary or recurrent CRLM scheduled for curative liver resection or thermal ablation based on CT staging will be enrolled from 17 centres across the Netherlands, Belgium, Norway, and Italy. All study participants will undergo CT and diffusion-weighted and gadoxetic-acid enhanced MRI prior to local therapy. The local multidisciplinary team will provide two local therapy plans: first, based on CT-staging and second, based on both CT and MRI. The primary outcome measure is the proportion of clinically significant CRLM (CS-CRLM) detected by MRI not visible on CT. CS-CRLM are defined as liver lesions leading to a change in local therapeutical management. If MRI detects new CRLM in segments which would have been resected in the original operative plan, these are not considered CS-CRLM. It is hypothesized that MRI will lead to the detection of CS-CRLM in ≥10% of patients which is considered the minimal clinically important difference. Furthermore, a prediction model will be developed using multivariable logistic regression modelling to evaluate the predictive value of patient, tumor and procedural variables on finding CS-CRLM on MRI.

DISCUSSION

The CAMINO study will clarify the clinical added value of MRI to CT in patients with CRLM scheduled for local therapy. This study will provide the evidence required for the implementation of additional MRI in the routine work-up of patients with primary and recurrent CRLM for local therapy.

TRIAL REGISTRATION

The CAMINO study was registered in the Netherlands National Trial Register under number NL8039 on September 20th 2019.

Staging Laparoscopy in Patients with Intrahepatic Cholangiocarcinoma: Is It Still Useful?

Background

The role of staging laparoscopy in patients with intrahepatic cholangiocarcinoma remains unclear. Despite extensive preoperative imaging, approximately 25% of patients are deemed unresectable at laparotomy due to metastasized disease. The aim of this study was to evaluate the frequency of unresectable disease found at staging laparoscopy and to identify predictors for detecting metastasized intrahepatic cholangiocarcinoma.

Methods

We retrospectively collected records of all patients with intrahepatic cholangiocarcinoma, presenting at our institution from 2008 to 2017. Staging laparoscopy was performed on the suspicion of distant metastases and on indication in larger tumors. The yield and sensitivity of staging laparoscopy was calculated. Reasons for unresectability at staging laparoscopy or laparotomy were recorded.

Results

Among a total of 80 patients with potentially resectable intrahepatic cholangiocarcinoma, 35 patients underwent staging laparoscopy on the suspicion of distant metastases. Unresectable disease was found at staging laparoscopy in 15 patients. Reasons for unresectability were liver metastasis (n = 6), peritoneal metastasis (n = 4), severe cirrhosis (n = 2), locally advanced tumor with satellite lesions (n = 1), and distant lymph node metastasis (n = 2). Considering optimal preoperative imaging, the true yield of staging laparoscopy was 20% (7/35). Two patients did not undergo laparotomy due to progression after staging laparoscopy. Of the remaining 18 patients who underwent laparotomy, 6 patients (30%) had unresectable disease, mostly because of distant metastasis (n = 4).

Conclusions

The role of staging laparoscopy to detect unresectable intrahepatic cholangiocarcinoma is highly dependent on the quality of preoperative imaging. Currently, no accurate selection criteria on imaging exist to select patients with intrahepatic cholangiocarcinoma who potentially benefit from staging laparoscopy.

[Computed tomography and/or magnetic resonance imaging of the liver : How, why, what for?]

CLINICAL PROBLEM

Colorectal metastases are the most common malignant liver lesions. Imaging of the liver in patients with colorectal carcinoma is performed for early detection of liver metastases (CRLM) at the time of initial tumor diagnosis, for monitoring and follow-up in order to exclude or diagnose metachronous metastases.

STANDARD RADIOLOGICAL METHODS

Radiological imaging includes primarily multislice computed tomography (CT) and magnetic resonance imaging (MRI), which play an important role regarding therapeutic management and assessment of prognosis.

PERFORMANCE, ACHIEVEMENTS

Contrast-enhanced CT is broadly available and allows for rapid image acquisition including the possibility for complete tumor staging. MRI, on the other hand, is characterized by very good soft tissue contrast and has-especially with the use of diffusion-weighted imaging and administration of liver-specific contrast agents-the highest sensitivity for detection of metastases smaller than 1 cm.

PRACTICAL RECOMMENDATIONS

The choice of imaging in daily routine is often dependent on availability and clinical question. Frequently, e.g. for assessment of resectability (extent of metastases, anatomic relation of lesions to critical structures), both modalities may be implemented in combination.

Health economic assessment of Gd-EOB-DTPA MRI versus ECCM-MRI and multi-detector CT for diagnosis of hepatocellular carcinoma in China

Limited data exists in China on the comparative cost of gadolinium ethoxybenzyl diethylenetriamine magnetic resonance imaging (Gd-EOB-DTPA-MRI) with other imaging techniques. This study compared the total cost of Gd-EOB-DTPA-MRI with multidetector computed tomography (MDCT) and extracellular contrast media-enhanced MRI (ECCM-MRI) as initial imaging procedures in patients with suspected hepatocellular carcinoma (HCC). We developed a decision-tree model on the basis of the Chinese clinical guidelines for HCC, which was validated by clinical experts from China. The model compared the diagnostic accuracy and costs of alternative initial imaging procedures. Compared with MDCT and ECCM-MRI, Gd-EOB-DTPA-MRI imaging was associated with higher rates of diagnostic accuracy, i.e. higher proportions of true positives (TP) and true negatives (TN) with lower false positives (FP). Total diagnosis and treatment cost per patient after the initial Gd-EOB-DTPA-MRI evaluation was similar to MDCT (¥30,360 vs. ¥30,803) and lower than that reported with ECCM-MRI (¥30,360 vs. ¥31,465). Lower treatment cost after initial Gd-EOB-DTPA-MRI was driven by reduced utilization of confirmatory diagnostic procedures and unnecessary treatments. The findings reported that Gd-EOB-DTPA-MRI offered higher diagnostic accuracy compared with MDCT and ECCM-MRI at a comparable cost, which indicates Gd-EOB-DTPA-MRI could be the preferred initial imaging procedure for the diagnosis of HCC in China.

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) in colorectal liver metastasis: the radiologist's perspective

PURPOSE

Hepatic resection is the only potentially curative treatment for patients with colorectal liver metastasis (CRLM). Many multidisciplinary approaches, including the associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) procedure, have been proposed to increase the resectability rate in these patients. ALPPS is the most recently described staged liver resection technique, representing an advantageous strategy to induce a rapid and marked increase in the future liver remnant (FLR) volume. The aim of this article is to describe the radiological evaluation of this procedure and its variation.

METHODS

This retrospective study included 9 patients with CRLM who underwent the ALPPS procedure. Abdominal imaging studies were reviewed, with an emphasis on a rational radiological approach. The number of liver metastases, the FLR volume (pre- and postportal vein ligation), anatomical variations, potential pitfalls related to disease progression, and postoperative complications were evaluated.

RESULTS

The types of hepatic resection included 4 classical ALPPS cases, 3 right ALPPS variations, and 2 left ALPPS variations. The mean FLR volume calculated in the initial evaluation was 453 mL (213-790 mL). Following the first surgery, the mean FLR volume increased to 634 mL (410-957 mL), which indicated a mean volume increase of 181.1 mL (95% CI 149.7-212.5 mL; p < 0.001) and a mean absolute volume increase of 48% (19%-88%).

CONCLUSION

The ALPPS procedure is an emerging form of two-stage hepatectomy. In this context, radiologists should provide crucial preoperative and perioperative information that may change surgical planning and contribute to an improvement in the oncologic outcome.

Role of imaging for patients with colorectal hepatic metastases: what the radiologist needs to know

Surgical resection of colorectal metastatic disease has increased as surgeons have adopted a more aggressive ideology. Current exclusion criteria are patients for whom a negative resection margin is not feasible or a future liver remnant (FLR) of greater than 20% is not achievable. The goal of preoperative imaging is to identify the number and distribution of liver metastases, in addition to establishing their relation to relevant intrahepatic structures. FLR can be calculated utilizing cross-sectional imaging to select out patients at risk for hepatic dysfunction after resection. MRI, specifically with gadoxetic acid contrast, is currently the preferred modality for assessment of hepatic involvement for patients with newly diagnosed colorectal cancer, to include those who have undergone neoadjuvant chemotherapy. Employment of liver-directed therapies has recently expanded and they may provide an alternative to hepatectomy in order to obtain locoregional control in poor surgical candidates or convert patients with initially unresectable disease into surgical candidates.

Gadoxetic acid: pearls and pitfalls

Gadoxetic acid is a hepatocyte-specific magnetic resonance imaging contrast agent with the ability to detect and characterize focal liver lesions and provide structural and functional information about the hepatobiliary system. Knowledge of the pharmacokinetics of gadoxetic acid is paramount to understanding imaging protocol and lesion appearance and facilitates identification and avoidance of undesired effects with use of this intravenous contrast agent. This article reviews the utility of gadoxetic acid in liver and biliary imaging, with emphasis on the hepatobiliary phase.

MRI with gadoxetate disodium for colorectal liver metastasis: is it the new "imaging modality of choice"?

BACKGROUND

Accurate detection of colorectal liver metastasis is paramount in the role of management. This study aims to compare magnetic resonance imaging (MRI) with gadoxetate disodium (a hepatocyte-specific agent-Eovist®) to triple-phase enhanced computed tomography in detecting colorectal liver metastases.

METHODS

A retrospective chart analysis of 30 patients from 2011 to 2013 with colorectal liver metastases was performed. Patients with more than 6 weeks or two cycles of chemotherapy between the two imaging modalities were excluded. The number of lesions identified on triple-phase enhanced computed tomography vs. MRI with Eovist® was compared.

RESULTS

Of the 30 patients that met the inclusion criteria, 12 (40 %) patients had more lesions identified on MRI with Eovist® compared to triple-phase enhanced computed tomography. Eighteen (60 %) had no change in the number of lesions identified. When MRI with Eovist® detected more lesions, the mean number of additional lesions detected was 1.5. Eovist® MRI changed the surgical management in 36.7 % of patients.

CONCLUSION

MRI with Eovist® is superior to enhanced computed tomography in identifying colorectal liver metastases. The increased number of lesion identified on MRI with Eovist® can profoundly change the surgeon's management. It should be considered the "imaging modality of choice" in preoperative imaging for liver metastases in these patients.

Surgical resection of a malignant liver lesion: what the surgeon wants the radiologist to know

OBJECTIVE

Hepatic malignancy is a common and lethal disease, whether due to a primary tumor or metastasis. There are numerous treatment options available depending on the stage of the disease and medical condition of the patient, including systemic chemotherapy, transcatheter embolization, thermal ablation, and surgical resection. In a subset of patients with liver malignancy, surgical resection can offer the best chance of long-term survival and potentially even cure. This article reviews the major indications and contraindications for resection, basic surgical techniques and terminology, key clinical and imaging preoperative workup, and pertinent interventional oncology procedures in the management of hepatic malignancy.

CONCLUSION

Diagnostic and interventional radiology plays an important role in the assessment and treatment of malignant hepatic lesions. Radiologists should be familiar with how surgeons select, work up, and treat candidates for liver resection to provide the most clinically valuable service.