Imaging of colorectal cancer liver metastases using contrast-enhanced US, multidetector CT, MRI, and FDG PET/CT: a meta-analysis

Baseline hepatobiliary MRI for predicting chemotherapeutic response and prognosis in initially unresectable colorectal cancer liver metastases

PURPOSE

To evaluate the performance of hepatobiliary MRI parameters as predictors of clinical response to chemotherapy in patients with initially unresectable colorectal cancer liver metastases (CRLM).

METHODS

Eighty-five patients with initially unresectable CRLM were retrospectively enrolled from two hospitals and scanned using gadobenate dimeglumine-enhanced MRI before treatment. Therapy response was evaluated based on the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Conventional parameters (i.e., signal intensity [SI]) and radiomics features of portal venous phase (PVP) and hepatobiliary phase (HBP) images were analyzed between the responders and non-responders. Next, the combined model was constructed, and the area under the receiver operating characteristic (ROC) curve (AUC) was calculated. The relationship between the combined model and progression-free survival (PFS) was analyzed using Cox regression.

RESULTS

Of the 85 patients from two hospitals, 42 were in the response group, and 43 were in the non-response group. Upon conducting five-fold cross-validation, the normalized relative enhancement (NRE) of CRLM during the PVP yielded an AUC of 0.625. Additionally, a radiomics feature derived from the tumor area in the HBP achieved an AUC of 0.698, while a separate feature extracted from the peritumoral region in the HBP recorded an AUC of 0.709. The model that integrated these three features outperformed the individual features, achieving an AUC of 0.818. Furthermore, the combined model exhibited a significant correlation with PFS (P < 0.001).

CONCLUSION

The combined model, based on baseline hepatobiliary MRI, aids in predicting chemotherapeutic response and PFS in patients with initially unresectable CRLM.

Influence of Covariates on 18F-FDG PET/CT Diagnostic Accuracy for Liver Metastasis

(1) Background: 18F-FDG PET/CT diagnostic accuracy for liver metastasis (LM) could be influenced by technical parameters, lesion size, and the patient's covariates. This retrospective study aimed to evaluate these covariates' impact on PET/CT sensitivity. (2) Methods: Consecutive patients with suspected LMs who underwent 18F-FDG PET/CT scans were included. PET/CT scans were interpreted visually. The reference standard integrated histopathological and imaging follow-up. Logistic regression modeling and average marginal predictions were used to calculate per-lesion diagnostic performance measures with cluster robust 95% confidence intervals and to assess the covariates' impact on PET/CT sensitivity. (3) Results: We included 192 patients with 330 lesions. 18F-FDG PET/CT exhibited a per-lesion sensitivity, specificity, positive predictive value, and negative predictive value of 86%, 79%, 91%, and 69%, respectively. In multivariate analysis, TOF PET/CT exhibited a higher sensitivity than non-TOF PET/CT (91% vs. 78%, p = 0.02). Sensitivity was reduced for lesions < 10 mm compared to larger lesions (56% vs. 93%, p < 0.001). A 5 kg/m2 increase in BMI led to an average 5% sensitivity reduction (p < 0.001). Age, sex, blood glucose level below 11 mmol/L, and liver density did not significantly impact sensitivity (p > 0.05). (4) Conclusions: 18F-FDG PET/CT sensitivity might be reduced with non-TOF PET, lesions < 10 mm, and higher BMI.

Deep learning CT reconstruction improves liver metastases detection

OBJECTIVES

Detection of liver metastases is crucial for guiding oncological management. Computed tomography through iterative reconstructions is widely used in this indication but has certain limitations. Deep learning image reconstructions (DLIR) use deep neural networks to achieve a significant noise reduction compared to iterative reconstructions. While reports have demonstrated improvements in image quality, their impact on liver metastases detection remains unclear. Our main objective was to determine whether DLIR affects the number of detected liver metastasis. Our secondary objective was to compare metastases conspicuity between the two reconstruction methods.

METHODS

CT images of 121 patients with liver metastases were reconstructed using a 50% adaptive statistical iterative reconstruction (50%-ASiR-V), and three levels of DLIR (DLIR-low, DLIR-medium, and DLIR-high). For each reconstruction, two double-blinded radiologists counted up to a maximum of ten metastases. Visibility and contour definitions were also assessed. Comparisons between methods for continuous parameters were performed using mixed models.

RESULTS

A higher number of metastases was detected by one reader with DLIR-high: 7 (2-10) (median (Q₁-Q₃); total 733) versus 5 (2-10), respectively for DLIR-medium, DLIR-low, and ASiR-V (p < 0.001). Ten patents were detected with more metastases with DLIR-high simultaneously by both readers and a third reader for confirmation. Metastases visibility and contour definition were better with DLIR than ASiR-V.

CONCLUSION

DLIR-high enhanced the detection and visibility of liver metastases compared to ASiR-V, and also increased the number of liver metastases detected.

CRITICAL RELEVANCE STATEMENT

Deep learning-based reconstruction at high strength allowed an increase in liver metastases detection compared to hybrid iterative reconstruction and can be used in clinical oncology imaging to help overcome the limitations of CT.

KEY POINTS

Detection of liver metastases is crucial but limited with standard CT reconstructions. More liver metastases were detected with deep-learning CT reconstruction compared to iterative reconstruction. Deep learning reconstructions are suitable for hepatic metastases staging and follow-up.

Ablation of Small Liver Metastases Presenting as Foci of Diffusion Restriction on MRI-Results from the Prospective Minimally Invasive Thermal Ablation (MITA) Study

PURPOSE

Liver metastases presenting as small hyperintense foci on diffusion-weighted imaging (DWI) pose a therapeutic challenge. Ablation is generally not possible since these lesions are often occult on ultrasound and CT. The purpose of this prospective study was to assess if small liver metastases (≤10 mm) detected on DWI can be successfully localized and ablated with the Hepatic Arteriography and C-Arm CT-Guided Ablation technique (HepACAGA).

MATERIALS AND METHODS

All consecutive patients with small liver metastases (≤10 mm), as measured on DWI, referred for ablation with HepACAGA between 1 January 2021, and 31 October 2023, were included. Re-ablations and ablations concomitant with another local treatment were excluded. The primary outcome was the technical success rate, defined as the intraprocedural detection and subsequent successful ablation of small liver metastases using HepACAGA. Secondary outcomes included the primary and secondary local tumor progression (LTP) rates and the complication rate.

RESULTS

A total of 15 patients (26 tumors) were included, with liver metastases from colorectal cancer (73%), neuro-endocrine tumors (15%), breast cancer (8%) and esophageal cancer (4%). All 26 tumors were successfully identified, punctured and ablated (a technical success rate of 100%). After a median follow-up of 9 months, primary and secondary LTP were 4% and 0%, respectively. No complications occurred.

CONCLUSION

In this proof-of-concept study, the HepACAGA technique was successfully used to detect and ablate 100% of small liver metastases identified on DWI with a low recurrence rate and no complications. This technique enables the ablation of subcentimeter liver metastases detected on MRI.

Imaging Considerations before and after Liver-Directed Locoregional Treatments for Metastatic Colorectal Cancer

Colorectal cancer is a leading cause of cancer-related death. Liver metastases will develop in over one-third of patients with colorectal cancer and are a major cause of morbidity and mortality. Even though surgical resection has been considered the mainstay of treatment, only approximately 20% of the patients are surgical candidates. Liver-directed locoregional therapies such as thermal ablation, Yttrium-90 transarterial radioembolization, and stereotactic body radiation therapy are pivotal in managing colorectal liver metastatic disease. Comprehensive pre- and post-intervention imaging, encompassing both anatomic and metabolic assessments, is invaluable for precise treatment planning, staging, treatment response assessment, and the prompt identification of local or distant tumor progression. This review outlines the value of imaging for colorectal liver metastatic disease and offers insights into imaging follow-up after locoregional liver-directed therapy.

Added Value of Liver MRI in Patients Eligible for Surgical Resection or Ablation of Colorectal Liver Metastases Based on CT: A Systematic Review and Meta-Analysis

Background

Abdominal computed tomography (CT) is the standard imaging modality for detection and staging in patients with colorectal liver metastases (CRLM). Although liver magnetic resonance imaging (MRI) is superior to CT in detecting small lesions, guidelines are ambiguous regarding the added value of an additional liver MRI in the surgical workup of patients with CRLM. Therefore, this systematic review and meta-analysis aimed to evaluate the clinical added value of liver MRI in patients eligible for resection or ablation of CRLM based on CT.

Methods

A systematic search was performed in the PubMed, Embase, and Cochrane Library databases through June 23, 2023. Studies investigating the impact of additional MRI on local treatment plan following CT in patients with CRLM were included. Risk of bias was assessed using the QUADAS-2 tool. The pooled weighted proportions for the primary outcome were calculated using random effect meta-analysis.

Results

Overall, 11 studies with 1440 patients were included, of whom 468 patients (32.5%) were assessed for change in local treatment plan. Contrast-enhanced liver MRI was used in 10 studies, including gadoxetic acid in 9 studies. Liver MRI with diffusion-weighted imaging was used in 8 studies. Pooling of data found a 24.12% (95% confidence interval, 15.58%-32.65%) change in the local treatment plan based on the added findings of liver MRI following CT. Sensitivity analysis including 5 studies (268 patients) focusing on monophasic portal venous CT followed by gadoxetic acid-enhanced liver MRI with diffusion-weighted imaging showed a change of local treatment plan of 17.88% (95% confidence interval, 5.14%-30.62%).

Conclusions

This systematic review and meta-analysis found that liver MRI changed the preinterventional local treatment plan in approximately one-fifth of patients eligible for surgical resection or ablation of CRLM based on CT. These findings suggest a clinically relevant added value of routine liver MRI in the preinterventional workup of CRLM, which should be confirmed by large prospective studies.

Exploring Potential Epigenetic Biomarkers for Colorectal Cancer Metastasis

Metastatic progression is a complex, multistep process and the leading cause of cancer mortality. There is growing evidence that emphasises the significance of epigenetic modification, specifically DNA methylation and histone modifications, in influencing colorectal (CRC) metastasis. Epigenetic modifications influence the expression of genes involved in various cellular processes, including the pathways associated with metastasis. These modifications could contribute to metastatic progression by enhancing oncogenes and silencing tumour suppressor genes. Moreover, specific epigenetic alterations enable cancer cells to acquire invasive and metastatic characteristics by altering cell adhesion, migration, and invasion-related pathways. Exploring the involvement of DNA methylation and histone modification is crucial for identifying biomarkers that impact cancer prediction for metastasis in CRC. This review provides a summary of the potential epigenetic biomarkers associated with metastasis in CRC, particularly DNA methylation and histone modifications, and examines the pathways associated with these biomarkers.

Comparison of outcomes between surgical treatment of colorectal cancer metastatic to the liver and the peritoneum: Review of the literature

BACKGROUND

Liver and peritoneum are two of the most common sites of colorectal metastases.

METHODS

We searched for articles comparing outcomes of surgical management for metastatic colorectal cancer to the liver and peritoneum.

CONCLUSION

Cytoreductive surgery/heated intraperitoneal chemotherapy has a similar safety profile and survival outcomes as hepatectomy for colorectal metastases after stratifying by resection status and should be incorporated earlier in the management algorithm for colorectal cancer patients with peritoneal metastases METHODS: We performed a wide search on PubMed, EMBASE, and Google Scholar for articles comparing outcomes of surgical management for metastatic colorectal cancer to the liver and peritoneum. We focused on studies comparing their perioperative clinical outcomes as well as their oncological outcomes. The following words were included in the search: comparison, outcomes, metastasectomy, colorectal cancer, liver, peritoneal surface disease, hepatectomy, and cytoreduction.

RESULTS

One hundred and twenty studies were evaluated. Six of these studies met the criteria for this review.

Contrast-enhanced ultrasound with microbubbles containing sulfur hexafluoride and perfluorobutane with Kupffer phase for the detection of colorectal liver metastases

OBJECTIVE

To compare contrast-enhanced ultrasound (CEUS) with microbubbles containing sulfur hexafluoride (SHF) and perfluorobutane (PFB) for the detection of colorectal liver metastasis (CRLM).

METHODS

In this prospective study, conducted from September to November 2021, patients with colorectal cancer were consecutively recruited and underwent same-day ultrasound, SHF-CEUS, and PFB-CEUS. The reference standard was contrast-enhanced MRI and follow-up imaging. The size, depth, echogenicity, and calcification of each focal liver lesion were recorded. The number and conspicuity of CRLMs, based on washout appearance during the late phase (LP) (> 120 s)/Kupffer phase (KP), were evaluated offsite by two blinded readers.

RESULTS

Overall, 230 lesions (CRLMs, n = 219; benign lesions, n = 11) in 78 patients were evaluated. Lesion conspicuity (p = 0.344) and accuracy in the detection of CRLM were comparable for SHF- and PFB-CEUS (0.877 for SHF vs. 0.770 for PFB, p = 0.087). More CRLMs ≥ 10 mm were identified by LP contrast washout in SHF-CEUS than in KP PFB-CEUS (p < 0.001). More CRLMs < 10 mm were identified by KP washout in PFB-CEUS than in LP SHF-CEUS (p < 0.001). Conspicuity was better on PFB-CEUS than on SHF-CEUS (p = 0.027). In hyperechoic lesions, lesions located deeper than 80 mm, and calcified lesions, CRLM conspicuity on PFB-CEUS was inferior to that on SHF-CEUS (p < 0.05).

CONCLUSIONS

The overall accuracy of detection and conspicuity of washout in CRLMs were comparable between SHF and PFB-CEUS. PFB-CEUS has the advantage of identifying washout in small CRLMs. However, larger, hyperechogenic, deep-seated, or calcified lesions were better identified using SHF-CEUS.

CLINICAL RELEVANCE STATEMENT

Accuracy of detection and conspicuity of washout in CRLMs were comparable between SHF- and PFB-CEUS. PFB-CEUS has the advantage in detecting small CRLMs, whereas SHF-CEUS is better for detecting larger, hyperechogenic, deep-seated, or calcified lesions.

KEY POINTS

Contrast-enhanced ultrasound with sulfur hexafluoride in the late phase and perfluorobutane microbubbles in the Kupffer phase were comparable in terms of accuracy in the detection and conspicuity of colorectal liver metastases. Small colorectal liver metastases (< 10 mm) were more often identified in the Kupffer phase contrast-enhanced ultrasound imaging when using perfluorobutane microbubbles. Larger, hyperechogenic, deep-seated, or calcified lesions were better identified in the late phase contrast-enhanced ultrasound imaging (> 120 s) when using sulfur hexafluoride microbubbles.

MRI in addition to CT in patients scheduled for local therapy of colorectal liver metastases (CAMINO): an international, multicentre, prospective, diagnostic accuracy trial

BACKGROUND

Guidelines are inconclusive on whether contrast-enhanced MRI using gadoxetic acid and diffusion-weighted imaging should be added routinely to CT in the investigation of patients with colorectal liver metastases who are scheduled for curative liver resection or thermal ablation, or both. Although contrast-enhanced MRI is reportedly superior than contrast-enhanced CT in the detection and characterisation of colorectal liver metastases, its effect on clinical patient management is unknown. We aimed to assess the clinical effect of an additional liver contrast-enhanced MRI on local treatment plan in patients with colorectal liver metastases amenable to local treatment, based on contrast-enhanced CT.

METHODS

We did an international, multicentre, prospective, incremental diagnostic accuracy trial in 14 liver surgery centres in the Netherlands, Belgium, Norway, and Italy. Participants were aged 18 years or older with histological proof of colorectal cancer, a WHO performance status score of 0-4, and primary or recurrent colorectal liver metastases, who were scheduled for local therapy based on contrast-enhanced CT. All patients had contrast-enhanced CT and liver contrast-enhanced MRI including diffusion-weighted imaging and gadoxetic acid as a contrast agent before undergoing local therapy. The primary outcome was change in the local clinical treatment plan (decided by the individual clinics) on the basis of liver contrast-enhanced MRI findings, analysed in the intention-to-image population. The minimal clinically important difference in the proportion of patients who would have change in their local treatment plan due to an additional liver contrast-enhanced MRI was 10%. This study is closed and registered in the Netherlands Trial Register, NL8039.

FINDINGS

Between Dec 17, 2019, and July 31, 2021, 325 patients with colorectal liver metastases were assessed for eligibility. 298 patients were enrolled and included in the intention-to-treat population, including 177 males (59%) and 121 females (41%) with planned local therapy based on contrast-enhanced CT. A change in the local treatment plan based on liver contrast-enhanced MRI findings was observed in 92 (31%; 95% CI 26-36) of 298 patients. Changes were made for 40 patients (13%) requiring more extensive local therapy, 11 patients (4%) requiring less extensive local therapy, and 34 patients (11%) in whom the indication for curative-intent local therapy was revoked, including 26 patients (9%) with too extensive disease and eight patients (3%) with benign lesions on liver contrast-enhanced MRI (confirmed by a median follow-up of 21·0 months [IQR 17·5-24·0]).

INTERPRETATION

Liver contrast-enhanced MRI should be considered in all patients scheduled for local treatment for colorectal liver metastases on the basis of contrast-enhanced CT imaging.

FUNDING

The Dutch Cancer Society and Bayer AG - Pharmaceuticals.

Diagnostic performance of whole-body [18F]FDG PET/MR in cancer M staging: A systematic review and meta-analysis

OBJECTIVES

To calculate the pooled diagnostic performances of whole-body [18F]FDG PET/MR in M staging of [18F]FDG-avid cancer entities.

METHODS

A diagnostic meta-analysis was conducted on the [18F]FDG PET/MR in M staging, including studies: (1) evaluated [18F]FDG PET/MR in detecting distant metastasis; (2) compared[ 18F]FDG PET/MR with histopathology, follow-up, or asynchronous multimodality imaging as the reference standard; (3) provided data for the whole-body evaluation; (4) provided adequate data to calculate the meta-analytic performances. Pooled performances were calculated with their confidence interval. In addition, forest plots, SROC curves, and likelihood ratio scatterplots were drawn. All analyses were performed using STATA 16.

RESULTS

From 52 eligible studies, 2289 patients and 2072 metastases were entered in the meta-analysis. The whole-body pooled sensitivities were 0.95 (95%CI: 0.91-0.97) and 0.97 (95%CI: 0.91-0.99) at the patient and lesion levels, respectively. The pooled specificities were 0.99 (95%CI: 0.97-1.00) and 0.97 (95%CI: 0.90-0.99), respectively. Additionally, subgroup analyses were performed. The calculated pooled sensitivities for lung, gastrointestinal, breast, and gynecological cancers were 0.90, 0.93, 1.00, and 0.97, respectively. The pooled specificities were 1.00, 0.98, 0.97, and 1.00, respectively. Furthermore, the pooled sensitivities for non-small cell lung, colorectal, and cervical cancers were 0.92, 0.96, and 0.86, respectively. The pooled specificities were 1.00, 0.95, and 1.00, respectively.

CONCLUSION

[18F]FDG PET/MR was a highly accurate modality in M staging in the reported [18F]FDG-avid malignancies. The results showed high sensitivity and specificity in each reviewed malignancy type. Thus, our findings may help clinicians and patients to be confident about the performance of [18F]FDG PET/MR in the clinic.

CLINICAL RELEVANCE STATEMENT

Although [18F]FDG PET/MR is not a routine imaging technique in current guidelines, mostly due to its availability and logistic issues, our findings might add to the limited evidence regarding its performance, showing a sensitivity of 0.95 and specificity of 0.97.

KEY POINTS

• The whole-body [18F]FDG PET/MR showed high accuracy in detecting distant metastases at both patient and lesion levels. • The pooled sensitivities were 95% and 97% and pooled specificities were 99% and 97% at patient and lesion levels, respectively. • The results suggested that 18F-FDG PET/MR was a strong modality in the exclusion and confirmation of distant metastases.

Metabolic Tumor Volume from 18F-FDG PET/CT in Combination with Radiologic Measurements to Predict Long-Term Survival Following Transplantation for Colorectal Liver Metastases

The aim of the present study is to report on the ability of metabolic tumor volume (MTV) of liver metastases from pre-transplant 18F-FDG PET/CT in combination with conventional radiological measurements from CT scans to predict long-term disease-free survival (DFS), overall survival (OS), and survival after relapse (SAR) after liver transplantation for colorectal liver metastases. The total liver MTV was obtained from the 18F-FDG PET/CT, and the size of the largest metastasis and the total number of metastases were obtained from the CT. DFS, OS, and SAR for patients with a low and high MTV, in combination with a low and high size, number, and tumor burden score, were compared using the Kaplan-Meier method and log-rank test. Patients with a low number of metastases and low MTV had a significantly longer OS than those with a high MTV, with a median survival of 151 vs. 26 months (p = 0.010). Patients with a high number of metastases and low MTV had significantly longer DFS, OS, and SAR than patients with a high MTV (p = 0.034, 0.006, and 0.026). The tumor burden score of group/zone 3, in combination with a low MTV, had a significantly improved DFS, OS, and SAR compared to those with a high MTV (p = 0.034, <0.001, and 0.006). Patients with a low MTV of liver metastases had a long DFS, OS, and SAR despite a high number of liver metastases and a high tumor burden score.

PET/CT in assessment of colorectal liver metastases: a comprehensive review with emphasis on 18F-FDG

Approximately 25% of those who are diagnosed with colorectal cancer will develop colorectal liver metastases (CRLM) as their illness advances. Despite major improvements in both diagnostic and treatment methods, the prognosis for patients with CRLM is still poor, with low survival rates. Accurate employment of imaging methods is critical in identifying the most effective treatment approach for CRLM. Different imaging modalities are used to evaluate CRLM, including positron emission tomography (PET)/computed tomography (CT). Among the PET radiotracers, fluoro-18-deoxyglucose (18F-FDG), a glucose analog, is commonly used as the primary radiotracer in assessment of CRLM. As the importance of 18F-FDG-PET/CT continues to grow in assessment of CRLM, developing a comprehensive understanding of this subject becomes imperative for healthcare professionals from diverse disciplines. The primary aim of this article is to offer a simplified and comprehensive explanation of PET/CT in the evaluation of CRLM, with a deliberate effort to minimize the use of technical nuclear medicine terminology. This approach intends to provide various healthcare professionals and researchers with a thorough understanding of the subject matter.

Defining MRI Superiority over CT for Colorectal and Neuroendocrine Liver Metastases

BACKGROUND

We compared CT and MRI for staging metastatic colorectal or neuroendocrine liver metastases (CRLMs and NELMs, respectively) to assess their impact on tumor burden.

METHODS

A prospectively maintained database was queried for patients who underwent both imaging modalities within 3 months, with two blinded radiologists (R1 and R2) independently assessing the images for liver lesions. To minimize recall bias, studies were grouped by modality, and were randomized and evaluated separately.

RESULTS

Our query yielded 76 patients (42 CRLMs; 34 NELMs) with low interrater variability (intraclass correlation coefficients: CT = 0.941, MRI = 0.975). For CRLMs, there were no significant differences in lesion number or size between CT and MRI. However, in NELMs, Eovist®-enhanced MRI detected more lesions (R1: 14.3 vs. 12.1, p = 0.02; R2: 14.4 vs. 12.4, p = 0.01) and smaller lesions (R1: 5.7 vs. 4.4, p = 0.03; R2: 4.8 vs. 2.9, p = 0.02) than CT.

CONCLUSIONS

CT and MRI are equivalent for CRLMs, but for NELMs, MRI outperforms CT in detecting more and smaller lesions, potentially influencing treatment planning and surgery.

The Role of 68Ga FAPI-04 and 18F-FDG PET/CT in Detecting Liver Metastases in Different Types of Cancer

OBJECTIVE

We compared the diagnostic accuracies of 68Ga FAPI-04 PET/CT and 18F-FDG PET/CT for detecting liver metastases (LMs) in patients with different cancer types.

MATERIALS AND METHODS

This retrospective study included 63 patients with liver lesions who underwent 18F-FDG PET/CT and 68Ga-FAPI-04 PET/CT between May 2020 and May 2022. Patients with histopathologically confirmed primary diagnoses, data that could be accessed retrospectively, liver lesions confirmed by biopsy over at least 3-6 months of follow-up (via ultrasonography, CT, magnetic resonance imaging, PET/CT, or laboratory tests) were included. Patients with secondary malignancies or primary liver malignancies, and/or who could not be followed-up, were excluded.

RESULTS

Of the 63 total patients, 34 (54%) were female, and the mean age was 61 (30-92) years. There were 582 LMs in 51 patients and 35 benign liver lesions in 20 (12 patients had only benign and 8 both benign and malignant lesions). Of the 582 LMs, 472 (81.1%) evidenced 18F-FDG uptake and 572 (98.2%) 68Ga-FAPI uptake. The diagnostic accuracies of 68Ga-FAPI PET/CT and 18F-FDG PET/CT were 98% and 82%, respectively (p < 0.001; McNemar test). When the LMs were compared, the maximum standardized uptake (SUVmax) value was significantly higher on 18F-FDG PET/CT than 68Ga-FAPI PET/CT (median: 6.0 vs. 5.4; p = 0.016). However, the LM-to-background ratio (TBR) was significantly higher on 68Ga-FAPI PET/CT than 18F-FDG PET/CT (median: 4.1 vs. 2.1; p < 0.001).

CONCLUSION

68Ga-FAPI PET/CT detected more LMs than did 18F-FDG PET/CT, and TBR was significantly higher on 68Ga-FAPI PET/CT than 18F-FDG PET/CT.

Oxaliplatin-Induced Sinusoidal Obstruction Syndrome Masquerading as Colorectal Liver Metastasis: A Case Report

INTRODUCTION

Oxaliplatin-based chemotherapy is commonly used in adjuvant treatment of colon cancer as well as in neoadjuvant setting in patients with liver metastases. However oxaliplatin can cause damage to non-tumor bearing liver which presents as sinusoidal obstructive syndrome (SOS). These changes are difficult to differentiate from metastasis clinic-radiologically and manifests as sinusoidal dilatation, peliosis and nodular regenerative hyperplasia.

CASE

The present study reports the case of a patient with oxaliplatin-induced SOS which mimicked colo-rectal liver metastasis on follow up imaging studies after receiving neoadjuvant oxaliplatin based chemotherapy. After multidisciplinary discussion, patient was planned for simultaneous resection of rectal primary and right hepatectomy for metastasis. Final histopathology revealed no tumour in liver but the liver lesions seen radiologically were actually changes of oxaliplatin induced focal SOS and mimicked metastatic nodules.

CONCLUSION

In patients with colo-rectal cancer having received oxaliplatin-based chemotherapy, SOS may be considered as one of the causes of newly developed liver lesions, and should be subjected to additional radio-pathologic evaluation to prevent overtreatment and avoiding potentially morbid surgeries.

The Management of Oligometastatic Disease in Colorectal Cancer: Present Strategies and Future Perspectives

Oligometastatic disease has been described as an intermediate clinical state between localized cancer and systemically metastasized disease. Recent clinical studies have shown prolonged survival when aggressive locoregional approaches are added to systemic therapies in patients with oligometastases. The aim of this review is to outline the newest options to treat oligometastatic colorectal cancer (CRC), also considering its molecular patterns. We present an overview of the available local treatment strategies, including surgical procedures, stereotactic body radiation therapy (SBRT), thermal ablation, as well as trans-arterial chemoembolization (TACE) and selective internal radiotherapy (SIRT). Moreover, since imaging methods provide crucial information for the early diagnosis and management of oligometastatic CRC, we discuss the role of modern radiologic techniques in selecting patients that are amenable to potentially curative locoregional treatments.

Comparison of 18 F-FDG and 68 Ga-FAPI-04 Uptake in Postoperative Re-evaluation of Gastric, Duodenal, and Colorectal Cancers

PURPOSE

To compare the potential efficacy of 68 Ga-FAPI-04 PET/CT with that of 18 F-FDG PET/CT for detecting tumor recurrence and nodal and distant metastases in gastric, duodenal, and colorectal cancers.

METHODS

This single-center retrospective clinical study was performed at the Affiliated Hospital of Southwest Medical University between January 2020 and June 2022. Participants with gastric, duodenal, and colorectal cancers after curative resection underwent both 68 Ga-FAPI-04 and 18 F-FDG PET/CT. Histopathologic examination, morphologic imaging, and/or follow-up imaging served as the reference standards. The SUV max of the tumor recurrence and nodal and distant metastases between 18 F-FDG and 68 Ga-FAPI-04 PET/CT were compared using the paired-sample t test.

RESULTS

Forty-one participants with gastric, duodenal, and colorectal cancers were enrolled in the study (median age, 51 years; range, 19-75 years). The sensitivity of 68 Ga-FAPI-04 PET/CT was higher than that of 18 F-FDG PET/CT for detecting tumor recurrence (6 of 6 [100%] vs 4 of 6 [67%]), nodal metastases (92 of 92 [100%] vs 31 of 92 [34%]), and distant metastases (28 of 30 [93%] vs 20 of 30 [67%]).

CONCLUSION

68 Ga-FAPI-04 PET/CT for tumor re-evaluation showed potential for more accurate performance of gastric, duodenal, and colorectal cancers, thereby improving treatment decision-making.

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.

Role of Positron Emission Tomography/Computed Tomography in Gastrointestinal Malignancies: A Brief Review and Pictorial Essay

Positron emission tomography/computed tomography (PET/CT) is increasingly becoming a mainstay in diagnosis and management of many malignant disorders. However, its role in the assessment of gastro-intestinal lesions is still evolving. The aim of this review was to demonstrate the areas, where PET/CT is impactful and where it has limitations. This will allow for us to reduce unnecessary investigations and develop methods to overcome the limitations.

High-frame-rate contrast-enhanced ultrasound findings of liver metastasis of duodenal gastrointestinal stromal tumor: A case report and literature review

BACKGROUND

Liver metastasis of duodenal gastrointestinal stromal tumor (GIST) is rare. Most reports mainly focus on its treatment and approaches to surgical resection, while details on its contrast-enhanced ultrasound (CEUS) findings are lacking. The diagnosis and imaging modalities for this condition remain challenging.

CASE SUMMARY

A 53-year-old Chinese man presented with mild signs and symptoms of the digestive tract. He underwent routine examinations after GIST surgery. Magnetic resonance imaging showed a 2.3 cm hepatic space-occupying lesion. All the laboratory test results were within normal limits. For further diagnostic confirmation, we conducted high frame rate CEUS (H-CEUS) and found a malignant perfusion pattern. Heterogeneous concentric hyper-enhancement, earlier wash-in than the liver parenchyma, and two irregular vessel columns could be observed at the periphery of the lesion during the arterial phase. Ultrasound-guided puncture biopsy was used to confirm the diagnosis of the lesion as liver metastasis of duodenal GIST. Imatinib was prescribed after biopsy, and the patient’s clinical course was monitored.

CONCLUSION

H-CEUS is useful for detecting microcirculation differences, wash-in patterns, and vascular morphogenesis and diagnosing liver metastasis of duodenal GIST.

Diagnostic performance of [18F]-FDG PET/MR in evaluating colorectal cancer: a systematic review and meta-analysis

PURPOSE

To calculate the diagnostic performance of [¹⁸F]-FDG PET/MR in colorectal cancer (CRC).

METHODS

This study was designed following the PRISMA-DTA guidelines. To be included, published original articles (until December 31, 2021) that met the following criteria were considered eligible: (1) evaluated [¹⁸F]-FDG PET/MR as the diagnostic method to detect CRC; (2) compared [¹⁸F]-FDG PET/MR with histopathology as the reference standard, or clinical/imaging composite follow-up when pathology was not available; (3) provided adequate crude data for meta-analysis. The diagnostic pooled measurements were calculated at patient and lesion levels. Regarding sub-group analysis, diagnostic measurements were calculated in "TNM staging," "T staging," "N staging," "M staging," and "liver metastasis" sub-groups. Additionally, we calculated the pooled performances in "rectal cancer: patient-level" and "rectal cancer: lesion-level" sub-groups. A hierarchical method was used to pool the performances. The bivariate model was conducted to find the summary points. Analyses were performed using STATA 16.

RESULTS

A total of 1534 patients from 18 studies were entered. The pooled sensitivities in CRC lesion detection (tumor, lymph nodes, and metastases) were 0.94 (95%CI: 0.89-0.97) and 0.93 (95%CI: 0.82-0.98) at patient-level and lesion-level, respectively. The pooled specificities were 0.89 (95%CI: 0.84-0.93) and 0.95 (95%CI: 0.90-0.98) at patient-level and lesion-level, respectively. In sub-groups, the highest sensitivity (0.97, 95%CI: 0.86-0.99) and specificity (0.99, 95%CI: 0.84-1.00) were calculated for "M staging" and "rectal cancer: lesion-level," respectively. The lowest sensitivity (0.81, 95%CI: 0.65-0.91) and specificity (0.79, 95%CI: 0.52-0.93) were calculated for "N staging" and "T staging," respectively.

CONCLUSION

This meta-analysis showed an overall high diagnostic performance for [¹⁸F]-FDG PET/MR in detecting CRC lesions/metastases. Thus, this modality can play a significant role in several clinical scenarios in CRC staging and restaging. Specifically, one of the main strengths of this modality is ruling out the existence of CRC lesions/metastases. Finally, the overall diagnostic performance was not found to be affected in the post-treatment setting.

A clinical trial of super-stable homogeneous lipiodol-nanoICG formulation-guided precise fluorescent laparoscopic hepatocellular carcinoma resection

Background

Applying traditional fluorescence navigation technologies in hepatocellular carcinoma is severely restricted by high false-positive rates, variable tumor differentiation, and unstable fluorescence performance.

Results

In this study, a green, economical and safe nanomedicine formulation technology was developed to construct carrier-free indocyanine green nanoparticles (nanoICG) with a small uniform size and better fluorescent properties without any molecular structure changes compared to the ICG molecule. Subsequently, nanoICG dispersed into lipiodol via a super-stable homogeneous intermixed formulation technology (SHIFT&nanoICG) for transhepatic arterial embolization combined with fluorescent laparoscopic hepatectomy to eliminate the existing shortcomings. A 52-year-old liver cancer patient was recruited for the clinical trial of SHIFT&nanoICG. We demonstrate that SHIFT&nanoICG could accurately identify and mark the lesion with excellent stability, embolism, optical imaging performance, and higher tumor-to-normal tissue ratio, especially in the detection of the microsatellite lesions (0.4 × 0.3 cm), which could not be detected by preoperative imaging, to realize a complete resection of hepatocellular carcinoma under fluorescence laparoscopy in a shorter period (within 2 h) and with less intraoperative blood loss (50 mL).

Conclusions

This simple and effective strategy integrates the diagnosis and treatment of hepatocellular carcinoma, and thus, it has great potential in various clinical applications.

Supplementary information

The online version contains supplementary material available at 10.1186/s12951-022-01467-w.

Benign focal liver lesions: The role of magnetic resonance imaging

Liver lesions are common findings in radiologists’ daily routine. They are a complex category of pathology that range from solitary benign lesions to primary liver cancer and liver metastases. Benign focal liver lesions can arise from different liver cell types: Epithelial (hepatocytes and biliary cells) and nonepithelial (mesenchymal cells). Liver magnetic resonance imaging (MRI) is a fundamental radiological method in these patients as it allows with its multiparametric approach optimal non-invasive tissue characterization. Furthermore, advanced liver MRI techniques such as diffusion-weighted imaging and hepatobiliary contrast agents have improved the detection of focal liver lesions and can be highly effective in differentiating pseudotumor from tumors, as well as benign from malignant lesions, and can also be used for differential diagnosis. Although histological examination can be useful in making a definitive diagnosis, MRI is an important modality in the diagnosis of liver lesions with a significant impact on patient care. This aim of this review is to provide a comprehensive overview of benign liver lesions on MRI.

Imaging of Colorectal Liver Metastasis

Colorectal cancer (CRC) is one of the most common cancers in the world. The most important determinant of survival and prognosis is the stage and presence of metastasis. The liver is the most common location for CRC metastasis. The only curative treatment for CRC liver metastasis (CRLM) is resection; however, many patients are ineligible for surgical resection of CRLM. Locoregional treatments such as ablation and intra-arterial therapy are also available for patients with CRLM. Assessment of response after chemotherapy is challenging due to anatomical and functional changes. Antiangiogenic agents such as bevacizumab that are used in the treatment of CRLM may show atypical patterns of response on imaging. It is vital to distinguish patterns of response in addition to toxicities to various treatments. Imaging plays a critical role in evaluating the characteristics of CRLM and the approach to treatment. CT is the modality of choice in the diagnosis and management of CRLM. MRI is best used for indeterminate lesions and to assess response to intra-arterial therapy. PET-CT is often utilized to detect extrahepatic metastasis. State-of-the-art imaging is critical to characterize patterns of response to various treatments. We herein review the imaging characteristics of CRLM with an emphasis on imaging changes following the most common CRLM treatments.

Investigating ultra-low-dose total-body [18F]-FDG PET/CT in colorectal cancer: initial experience

PURPOSE

This study was to evaluate the effects of an ultra-low dose of [18F]-FDG on the image quality of total-body PET/CT and its lesion detectability in colorectal cancer (CRC).

METHODS

Sixty-two CRC patients who underwent total-body PET/CT (uEXPLORER, United Imaging Healthcare, Shanghai, China) with an ultra-low dose (0.37 MBq/kg) of [18F]-FDG were enrolled in this retrospective study. The PET images were reconstructed with the entire 15-min dataset first and then split into 13-, 8-, 5-, 4-, 3-, 2-, and 1-min duration groups to simulate fast scanning images. For simplicity, the images reconstructed with the data from 15 to 1 min were referred to as G15, G13, and so on until G1. Subjective image quality was assessed with 5-point Likert scales. The objective image quality parameters included the SUVmax, SUVmean, and signal-to-noise ratio (SNR) of the liver and blood pool and the SUVmax and tumor-to-background ratio (TBR) of the lesions. G15 served as the control to evaluate lesion detectability.

RESULTS

A total of 62 patients (43 men, 19 women; age 41-88, mean ± SD 64.0 ± 10.9 years) with 64 CRC primary tumor lesions and 10 low-grade intraepithelial neoplasia (LGIN) lesions were enrolled in this study. The subjective scores were highest for G15 (4.5 ± 0.5) and then decreased from G13 (4.3 ± 0.4) to G8 (3.7 ± 0.5). The liver SNR increased with the extension of acquisition time from G8 (17.2 ± 2.8) to G13 (20.6 ± 3.4) and G15 (21.9 ± 3.4). The liver SNR of G8 was not significantly different from that of G13 (p = 0.15) and was significantly different from that of G15 (p = 0.001). All 64 CRC lesions could be identified in all image groups, even on G1. One of ten LGINs was missed on G1, G2, and G3, and one LGIN was missed on G1, G2, G3, and G4. G15 served as the control, and 100% (48/48) lymph nodes could be found on G13 and G8 compared to 93.8% (45/48) lymph nodes on G5 and G4, 85.4% (41/48) lymph nodes on G3, 81.3% (39/48) lymph nodes on G2, and 77.1% (37/48) lymph nodes on G1. For liver metastases, there were no missed liver lesions on G13 and G8 and 3, 4, 6, 7, and 9 missed liver lesions on G5, G4, G3, G2, and G1, respectively. For other areas of metastasis, including the lung, peritoneum, and ovaries, there were no missed lesions in any group.

CONCLUSIONS

Total-body PET/CT with an ultra-low dose of [18F]-FDG can maintain satisfactory image quality and lesion detectability in CRC.

Practical Considerations When Interpreting FDG PET/CT Imaging for Staging and Treatment Response Assessment in Melanoma Patients

While FDG PET/CT bears a high sensitivity and specificity for the staging of stage III and IV melanoma as well as for the purpose of melanoma recurrence detection, overall results tend to vary from one part of the body to another as well as for melanoma from cutaneous or choroidal origin. In this paper, organ or site-related differences in sensitivity and specificity in melanoma patients, both from cutaneous and choroidal origin, as well as their impact on clinical decision making are discussed. Furthermore, with the advent of immunotherapy for the treatment of malignant melanoma, post-treatment related potential false positive findings have emerged, the knowledge of which is essential for accurate treatment response assessment. These post-treatment related potential false positive findings are summarized in this paper so as to help the nuclear medicine physician in avoiding erroneous interpretation of acquired FDG PET/CT images in melanoma patients receiving immuntherapy.

Artificial intelligence performance in detecting tumor metastasis from medical radiology imaging: A systematic review and meta-analysis

BACKGROUND

Early diagnosis of tumor metastasis is crucial for clinical treatment. Artificial intelligence (AI) has shown great promise in the field of medicine. We therefore aimed to evaluate the diagnostic accuracy of AI algorithms in detecting tumor metastasis using medical radiology imaging.

METHODS

We searched PubMed and Web of Science for studies published from January 1, 1997, to January 30, 2020. Studies evaluating an AI model for the diagnosis of tumor metastasis from medical images were included. We excluded studies that used histopathology images or medical wave-form data and those focused on the region segmentation of interest. Studies providing enough information to construct contingency tables were included in a meta-analysis.

FINDINGS

We identified 2620 studies, of which 69 were included. Among them, 34 studies were included in a meta-analysis with a pooled sensitivity of 82% (95% CI 79-84%), specificity of 84% (82-87%) and AUC of 0·90 (0·87-0·92). Analysis for different AI algorithms showed a pooled sensitivity of 87% (83-90%) for machine learning and 86% (82-89%) for deep learning, and a pooled specificity of 89% (82-93%) for machine learning, and 87% (82-91%) for deep learning.

INTERPRETATION

AI algorithms may be used for the diagnosis of tumor metastasis using medical radiology imaging with equivalent or even better performance to health-care professionals, in terms of sensitivity and specificity. At the same time, rigorous reporting standards with external validation and comparison to health-care professionals are urgently needed for AI application in the medical field.

FUNDING

College students' innovative entrepreneurial training plan program .