Detection of hepatic metastases from cancers of the gastrointestinal tract by using noninvasive imaging methods (US, CT, MR imaging, PET): a meta-analysis

[Importance of FDG-PET/computed tomography in colorectal cancer]

BACKGROUND

Hybrid imaging FDG PET/CT (¹⁸F‑fluordeoxyglucose positron emission tomography/computed tomography) has gained increasing importance in oncology in recent years.

DIAGNOSIS

A focal increase in FDG uptake in the gastrointestinal tract may be due to colorectal carcinoma. Such a finding requires further clarification.

PRIMARY STAGING

Staging of the primary and locoregional lymph nodes remains a domain of established imaging modalities as FDG PET/CT does not provide a clear additional benefit. Liver metastases can be detected with high sensitivity by FDG PET/CT, but MRI is superior in small lesions.

RADIATION THERAPY PLANNING

So far FDG PET/CT plays a subordinate role in the radiation therapy planning of rectal cancer. However, it can potentially contribute to the optimization of planning target volumes.

THERAPY MONITORING

FDG PET/CT is suitable for monitoring therapy because morphological and metabolic changes of the tumor can be detected in early stages. This enables early detection of nonresponders after beginning neoadjuvant chemoradiation therapy of rectal cancer. FDG PET/CT can also be used for therapy control of liver metastases, especially after local therapeutic procedures.

DETECTION OF RECURRENCE

With clinical suspicion of local recurrence and increased tumor markers, FDG PET/CT is a valuable tool as tumor recurrence can be detected with high sensitivity and specificity.

Positron emission tomography with computed tomography imaging (PET/CT) for the radiotherapy planning definition of the biological target volume: PART 2

AIM

Positron Emission Tomography with Computed Tomography (PET/CT) has been proven to be useful in the definition of Radiotherapy (RT) target volume. In this regard, the present expert review summarizes existing data for pancreas, prostate, gynecological and rectum/anal cancer.

METHODS

A comprehensive search of published original article was made, based on SCOPUS and PubMed database, selecting the paper that evaluated the role of PET/CT in the definition of RT volume.

RESULTS

FDG-PET has an important and promising role for pancreatic cancer. Choline PET/CT could be useful for identifying high-risk volumes for prostate cancer; while PSMA PET/CT is still under evaluation. FDG PET/CT in gynecological cancers has been shown to impact external-beam RT planning. The role of FDG-PET for Gross Tumor volume identification is crucial, representing a useful and powerful tool for anal and rectal cancer.

CONCLUSION

Taken together, molecular and functional imaging approaches offer a major step to individualize radiotherapeutic approach.

Preoperative Metabolic Tumor Volume2.5 Associated with Early Systemic Metastasis in Resected Pancreatic Cancer: A Transcriptome-Wide Analysis

BACKGROUND/AIMS

18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) reflects biological aggressiveness and predicts prognoses in various tumors. Evaluating the oncologic significance of the preoperative metabolic phenotype might be necessary for planning the surgical strategy in resectable pancreatic cancers.

METHODS

From January 2010 to December 2015, a total of 93 patients with pathologic T3 (pT3) pancreatic cancer were included in this study. Clinicopathological parameters and PET parameters were evaluated, and transcriptome-wide analysis was performed to identify the oncologic impact and molecular landscape of the metabolic phenotype of resectable pancreatic cancers.

RESULTS

Preoperative metabolic tumor volume (MTV)2.5 was significantly higher in the pN1 group compared to the pN0 group (11.1±11.2 vs 6.5±7.8, p=0.031). Higher MTV2.5 values (MTV2.5 ≥4.5) were associated with multiple lymph node metastasis (p=0.003), and the lymph node ratio was also significantly higher in resected pT3 pancreatic cancer with MTV2.5 ≥4.5 compared to those with MTV2.5 <4.5 (0.12±0.13vs 0.05±0.08, p=0.001). Disease-specific survival of patientswith MTV2.5 <4.5 was better than that of patients withMTV2.5 ≥4.5 (mean, 28.8 months; 95% confidence interval[CI], 40.1 to 57.0 vs mean, 32.6 months; 95% CI, 25.5 to 39.7; p=0.026). Patients with MTV2.5 ≥4.5 who received postoperative adjuvant chemotherapy showed better survival outcomes than patients with MTV2.5 ≥4.5 who did not receive adjuvant treatment in resected pT3 pancreatic cancers (p<0.001). Transcriptome-wide analysis revealed that tumors with MTV2.5 ≥4.5 demonstrated significantly different expression of cancer-related genes reflecting aggressive tumor biology.

CONCLUSIONS

Resectable pancreatic cancer with high MTV2.5 is not only associated with lymph node metastasis but also early systemic metastasis. The molecular background of resectable pancreatic cancer with high MTV2.5 may be associated with aggressive biologic behavior, which might need to be considered when managing resectable pancreatic cancers. Further study is mandatory.

18F-FDG PET/CT AS AN ASSESSMENT TOOL OF HEPATOCELLULAR CARCINOMA SECONDARY TO NON-ALCOHOLIC FATTY LIVER DISEASE DEVELOPMENT IN EXPERIMENTAL MODEL

BACKGROUND

Hepatocellular carcinoma (HCC) can be the last step of non-alcoholic fatty liver disease (NAFLD) evolution. Experimental models are crucial to elucidate the pathogenesis of HCC secondary to NAFLD. The 2-deoxy-2-(18F)fluoro-D-glucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) plays an important role in evaluating HCC development and progression.

OBJECTIVE

To standardize the imaging method of PET/CT with 18F-FDG as an evaluation tool of the experimental model of HCC secondary to NAFLD.

METHODS

Ten male Sprague-Dawley rats were fed with choline-deficient high-fat diet and diethylnitrosamine (DEN) in the drinking water for 16 weeks and then received 1 mL of saline solution (0.9%) daily by gavage for three weeks. At the 16th and 19th weeks, abdominal ultrasonography (USG) was performed. 18F-FDG PET/CT images were obtained before the beginning of experiment (week 0) and at the end (week 19). Histological and immunohistochemically analysis were also performed.

RESULTS

The USG results showed a homogeneous group at the 16th week with an average of 4.6±2.74 nodules per animal. At the 19th week, PET/CT findings demonstrated an average of 8.5±3.7 nodules per animal. The mean values of SUVmed and SUVmax were 2.186±0.1698 and 3.8±1.74, respectively. The average number of nodules per animal in the histological analysis was 5.5±1.5. From all nodules, 4.6% were classified as well-differentiated HCC and 81.8% were classified as poorly-differentiated HCC.

CONCLUSION

18F-FDG PET/CT was able to evaluate the development of HCC in an experimental model of NAFLD non-invasively. From the standardization of PET/CT in this model, it is possible to use this tool in future studies to monitor, in vivo and non-invasively, the progression of HCC.

A 3E8.scFv.Cys-IR800 Conjugate Targeting TAG-72 in an Orthotopic Colorectal Cancer Model

PURPOSE

Optical surgical navigation (OSN) will be a potent tool to help surgeons more accurately and efficiently remove tumors. The purpose of this study was to evaluate a novel humanized 3E8 antibody (3E8 MAb) fragment site-specifically conjugated with IR800, 3E8.scFv.Cys-IR800, as a potential OSN agent to target colorectal adenocarcinoma.

PROCEDURES

An engineered single-chain variable fragment of 3E8 MAb (targeted to TAG-72), appending a C-terminal cysteine residue (3E8.scFv.Cys), was created and reacted with IRDye800-maleimide. 3E8.scFv.Cys-IR800 identity and purity were verified by MALDI-TOF mass spectra and 800 nm detected size exclusion column HPLC. In vitro human colon adenocarcinoma LS-174 T cells binding and competition assay validated biological functionality. We further evaluated the imaging ability and receptor-specific binding of 3E8.scFv.Cys-IR800 in an orthotopic LS-174 T mouse model.

RESULTS

A 1:1 dye to protein conjugate was achieved at greater than 90 % HPLC purity. A 1 nmol dose of 3E8.scFv.Cys-IR800 via intraperitoneal injection administration was sufficient to produce high tumor to background fluorescence contrast. Blocking competition studies both in vitro and in vivo using a different blocking protein, 3E8ΔCH2, demonstrated 3E8.scFv.Cys-IR800 binding specificity for TAG-72 antigen.

CONCLUSIONS

3E8.scFv.Cys-IR800 shows properties useful in a clinically viable OSN agent for colorectal cancer.

Lower Gastrointestinal Tract Applications of PET/Computed Tomography and PET/MR Imaging

This article discusses the role of PET/CT and PET/MR imaging in the evaluation of inflammatory and malignant disorders of the lower gastrointestinal tract. This includes a review of the current literature and a discussion of new and emerging research.

Smart-Dust-Nanorice for Enhancement of Endogenous Raman Signal, Contrast in Photoacoustic Imaging, and T2-Shortening in Magnetic Resonance Imaging

Raman microspectroscopy provides chemo-selective image contrast, sub-micrometer resolution, and multiplexing capabilities. However, it suffers from weak signals resulting in image-acquisition times of up to several hours. Surface-enhanced Raman scattering (SERS) can dramatically enhance signals of molecules in close vicinity of metallic surfaces and overcome this limitation. Multimodal, SERS-active nanoparticles are usually labeled with Raman marker molecules, limiting SERS to the coating material. In order to realize multimodal imaging while acquiring the rich endogenous vibronic information of the specimen, a core-shell particle based on "Nanorice", where a spindle-shaped iron oxide core is encapsulated by a closed gold shell, is developed. An ultrathin layer of silica prevents agglomeration and unwanted chemical interaction with the specimen. This approach provides Raman signal enhancement due to plasmon resonance effects of the shell while the optical absorption in the near-infrared spectral region provides contrast in photoacoustic tomography. Finally, T2-relaxation of a magnetic resonance imaging (MRI) experiment is altered by taking advantage of the iron oxide core. The feasibility for Raman imaging is evaluated by nearfield simulations and experimental studies on the primate cell line COS1. MRI and photoacoustics are demonstrated in agarose phantoms illustrating the promising translational nature of this strategy for clinical applications in radiology.

Precise targeting of cancer metastasis using multi-ligand nanoparticles incorporating four different ligands

Metastasis displays a highly heterogeneous cellular population with cancer cells continuously evolving. As a result, a single-ligand nanoparticle cannot account for the continuously changing expression of targetable biomarkers over time and space. To effectively direct nanoparticles to metastasis, we developed a multi-ligand nanoparticle by using four different types of ligands on the same nanoparticle that target biomarkers on the endothelium associated with metastatic disease. These vascular targets included αvβ3 integrin, P-selectin, EGFR and fibronectin. Using terminal and in vivo imaging studies, the targeting performance of the multi-ligand nanoparticles was compared to the single-ligand nanoparticle variants. All four single-ligand nanoparticle variants achieved significant targeting of lung metastasis in the 4T1 mouse model of breast cancer metastasis with about 2.5% of the injected dose being deposited into metastasis. A dual-ligand nanoparticle resulted in a nearly 2-fold higher deposition into lung metastases than its single-ligand counterparts. The multi-ligand nanoparticle significantly outperformed its targeting nanoparticle counterparts achieving a deposition of ∼7% of its injected nanoparticles into lung metastases. Using the high sensitivity of radionuclide imaging, PET imaging showed that a multi-ligand nanoparticle labeled with [18F]fluoride was able to precisely target metastatic disease at its very early stage of development in three different animal models of metastatic breast cancer.

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.

Liver enhancement in healthy dogs after gadoxetic acid administration during dynamic contrast-enhanced magnetic resonance imaging

Dynamic contrast enhanced (DCE)-magnetic resonance imaging (MRI) consists of acquisition of native baseline images, followed by a series of acquisitions performed during and after administration of a contrast medium. DCE-MRI, in conjunction with hepatobiliary-specific contrast media, such as gadoxetic acid (GD-EOB-DTPA), allows for precise characterisation of the enhancement pattern of the hepatic parenchyma following administration of the contrast agent. The aim of the study was to assess the pattern of temporal resolution contrast enhancement of the hepatic parenchyma following administration of GD-EOB-DTPA and to determine the optimal time window for post-contrast assessment of the liver. The study was carried out on eight healthy beagle dogs. MRI was performed using a 1.5T scanner. The imaging protocol included T1 weighted (T1-W) gradient echo (GRE), T2 weighted (T2-W) turbo spin echo (TSE) and dynamic T1-W GRE sequences. The dynamic T1-W sequence was performed using single 10mm thick slices. Regions of interest (ROIs) were chosen and the signal intensity curves were calculated for quantitative image analysis. The mean time to peak for all dogs was 26min. The plateau phase lasted on average 21min. A gradual decrease in the signal intensity of the hepatic parenchyma was observed in all dogs. A DCE-MRI enhancement pattern of the hepatic parenchyma was evident in dogs following the administration of a GD-EOB-DTPA, establishing baseline data for an optimal time window between 26 and 41min after administration of the contrast agent.

CD133+CD54+CD44+ circulating tumor cells as a biomarker of treatment selection and liver metastasis in patients with colorectal cancer

Introduction

Liver is the most common site of distant metastasis in colorectal cancer (CRC). Early diagnosis and appropriate treatment selection decides overall prognosis of patients. However, current diagnostic measures were basically imaging but not functional. Circulating tumor cells (CTCs) known as hold the key to understand the biology of metastatic mechanism provide a novel and auxiliary diagnostic strategy for CRC with liver metastasis (CRC-LM).

Results

The expression of CD133⁺ and CD133⁺CD54⁺CD44⁺ cellular subpopulations were higher in the peripheral blood of CRC-LM patients when compared with those without metastasis (P<0.001). Multivariate analysis proved the association between the expression of CD133⁺CD44⁺CD54⁺ cellular subpopulation and the existence of CRC-LM (P<0.001). The combination of abdominal CT/MRI, CEA and the CD133⁺CD44⁺CD54⁺ cellular subpopulation showed increased detection and discrimination rate for liver metastasis, with a sensitivity of 88.2% and a specificity of 92.4%. Meanwhile, it also show accurate predictive value for liver metastasis (OR=2.898, 95% C.I.1.374–6.110).

Materials and Method

Flow cytometry and multivariate analysis was performed to detect the expression of cancer initiating cells the correlation between cellular subpopulations and liver metastasis in patients with CRC. The receiver operating characteristic curves combined with the area under the curve were generated to compare the predictive ability of the cellular subpopulation for liver metastasis with current CT and MRI images.

Conclusions

The identification, expression and application of CTC subpopulations will provide an ideal cellular predictive marker for CRC liver metastasis and a potential marker for further investigation.

Contrast enhanced ultrasound guided biopsies of liver lesions not visualized on standard B-mode ultrasound-preliminary experience

Background

To assess the technical success of contrast enhanced ultrasound (CEUS) guided biopsies of liver lesions poorly visualized on B-mode ultrasound.

Methods

Patients were selected during the procedure based on the real-time clinical scenario of unsatisfactory B-mode ultrasound lesion visualization and all patients would have otherwise undergone CT guided liver lesion biopsy. A total of 26 patients underwent CEUS guided biopsy and were included in this retrospective analysis. The review of the patients' files included demographic information, lesion characteristics on imaging, procedural details and pathology outcome. Technical success was defined as concordance between the radiological findings, pathology report and clinical follow-up-demonstrating lack of need for re-biopsy or re-biopsy with identical pathological results. Patients with less than 2 months follow-up were excluded from the study.

Results

CEUS guided liver biopsy was successful in 23 out of 26 patients (88.5%). The average procedure time was 30.7±12.3 minutes and the average lesion size was 2.2±1.7 cm. The majority of lesions (80.8%) were hypoenhancing on the delayed phase of CEUS. The mean number of samples taken from each lesion per procedure was 3.2 (±1.7).

Conclusions

CEUS guidance biopsies of focal liver lesions (FLL) that were difficult to visualize on B-mode ultrasound demonstrated high success rate and may be an evolving image guidance modality in selected patients to avoid CT guided procedures.

Liver metastases: Detection and staging

The liver is more often involved with metastatic disease than primary liver tumors. The accurate detection and characterization of liver metastases are crucial since patient management depends on it. The imaging options, mainly consisting of contrast-enhanced ultrasound (CEUS), multidetector computed tomography (CT), magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI), extra-cellular contrast media and liver-specific contrast media as well as positron emission tomography/computed tomography (PET/CT), are constantly evolving. PET/MRI is a more recent hybrid method and a topic of major interest concerning liver metastases detection and characterization. This review gives a brief overview about the spectrum of imaging findings and focus on an update about the performance, advantages and potential limitations of each modality as well as current developments and innovations.

Care of cancer patients with liver and bone metastases - the place of pharmaceutical care in a balanced plan, focused on the patient's needs and goals

Metastatic cancer, especially in the growing population of geriatric patients, presents a big challenge to these patients, as well as to treatment teams and the entire health care system. This article describes some common medical problems faced by patients with metastases to liver and bone, and presents a diagnostic approach, and therapeutic management of various symptoms, relevant to advanced stages of the malignant disease. The article highlights the importance of patient education on various aspects of metastatic cancer, and underscores the unique position of pharmacists practicing pharmaceutical care, which is particularly beneficial in this group of patients with advanced malignancy. Also, this paper emphasizes that achieving a proper balance between managing the malignant disease and maintaining the patients' quality of life, especially in the elderly population, should involve coordinated efforts of the oncology treatment team, primary care physicians, pharmacists, therapists and nurses, as well as patients, their families and caregivers.

Evaluation of recurrence in gastric carcinoma: Comparison of contrast-enhanced computed tomography and positron emission tomography/computed tomography

AIM

To compare the value of contrast-enhanced abdominal computed tomography (CT) and fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for detecting gastric carcinoma recurrence.

METHODS

We retrospectively examined data from 2475 patients who underwent both contrast-enhanced abdominal CT and FDG PET/CT for the surveillance of gastric carcinoma curative resection. Patients had an interval of less than 1 mo between their CT and PET/CT scans. Sixty patients who had recurrence were enrolled. Among 1896 patients who did not have recurrence, 60 were selected by simple random sampling. All CT and PET/CT images were reviewed retrospectively by two reviewers blinded to all clinical and pathologic information except curative resection due to gastric carcinoma.

RESULTS

The pathological stage of the recurrence group was statistically significantly higher than that of the control group (P < 0.001). In the 60 patients who had recurrence, there were 79 recurrent lesions. Forty-four patients had only one location of recurrence, 13 patients had two locations, and 3 patients had three. In the detection of patient-based overall recurrence, no statistically significant differences existed between the two modalities (P = 0.096). However, for peritoneal carcinomatosis, CT had a statistically significantly higher sensitivity compared to PET/CT (96% vs 50%, P = 0.001). Adenocarcinoma was the most common type of gastric carcinoma. On the pathology-based analysis, CT also had a statistically significantly higher sensitivity compared to PET/CT (98% vs 80%, P = 0.035).

CONCLUSION

Contrast-enhanced CT was superior to PET/CT in the detection of peritoneal carcinomatosis and pathologic type of adenocarcinoma.

Imaging of Hepatic Metastases

BACKGROUND

Imaging plays an important role not only in screening, evaluating, staging, and monitoring disease, but also in surveillance following tumor ablation. Advances in imaging techniques have increased our ability to detect and characterize focal liver lesions, resulting in improvements in diagnostic capability and improved monitoring of liver metastases. This has led to increased interest in both hepatic imaging and image-guided hepatic interventions.

METHODS

Several imaging options are reviewed according to their effective application, notably computed tomography (CT), CT during arterial portography, ultrasound, magnetic resonance imaging, positron emission tomography, and integrated PET/CT imaging.

RESULTS

Although there are exceptions regarding imaging options based on patient selection and on institution preference and expertise, multidetector helical CT scanning remains the dominant modality in the evaluation of suspected hepatic metastases, and for preoperative planning, treatment monitoring, and posttreatment follow-up.

CONCLUSIONS

Ultimately, the choice of imaging modality must be based not only on the patient and the clinical situation, but also on the imaging expertise within each institution.

High-Contrast Fluorescence Detection of Metastatic Breast Cancer Including Bone and Liver Micrometastases via Size-Controlled pH-Activatable Water-Soluble Probes

Breast cancer metastasis is the major cause of cancer death in women worldwide. Early detection would save many lives, but current fluorescence imaging probes are limited in their detection ability, particularly of bone and liver micrometastases. Herein, probes that are capable of imaging tiny (<1 mm) micrometastases in the liver, lung, pancreas, kidneys, and bone, that have disseminated from the primary site, are reported. The influence of the poly(ethylene glycol) (PEG) chain length on the performance of water-soluble, pH-responsive, near-infrared 4,4'-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) probes is systematically investigated to demonstrate that PEG tuning can provide control over micrometastasis tracking with high tumor-to-background contrast (up to 12/1). Optimized probes can effectively visualize tumor boundaries and successfully detect micrometastases with diameters <1 mm. The bone-metastasis-targeting ability of these probes is further enhanced by covalent functionalization with bisphosphonate. This improved detection of both bone and liver micrometastases (<2 mm) with excellent tumor-to-normal contrast (5.2/1). A versatile method is thus introduced to directly synthesize modular water-soluble probes with broad potential utility. Through a single intravenous injection, these materials can image micrometastases in multiple organs with spatiotemporal resolution. They thus hold promise for metastasis diagnosis, image-guided surgery, and theranostic PEGylated drug therapies.

FDG-PET/CT in the Postoperative Period: Utility, Expected Findings, Complications, and Pitfalls

FDG-PET/CT as a modality is increasingly used for detection of recurrence and for restaging in patients with clinical suspicion of malignancy, as well as in patients with elevated tumor markers. However, there are many pitfalls in the interpretation of these scans when the studies are performed after some treatment. Some of these are attributed to normal physiological distribution and are compounded when there are inflammatory changes occurring after surgery. The body's inherent response to the surgical insult results in this inflammation. In addition, there are also complications that can happen following surgery, causing increased FDG uptake. Despite various fallacies, FDG-PET/CT provides valuable information in evaluation of residual and recurrent malignant disease. In this article, we aim to describe some of these postsurgical changes secondary to inflammation, common surgical complications, and finally, the utility of FDG-PET/CT in these patients to detect recurrent disease, even in the background of postsurgical changes.

Fluorodeoxyglucose-positron emission tomography/computed tomography performs better than contrast-enhanced computed tomography for metastasis evaluation in the initial staging of pancreatic adenocarcinoma

OBJECTIVE

To evaluate the additional role of FDG-PET/CT to the conventional multiphasic CECT in the initial staging of pancreatic adenocarcinoma.

METHODS

54 patients diagnosed with pathologically proven pancreatic malignancy underwent FDG-PET/CECT. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal and metastatic staging were calculated. The statistical difference was calculated by McNemar's test.

RESULTS

Of 54 patients, 15 had distal metastasis. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT for nodal staging were 33 vs 89%, 84 vs 100%, 67 vs 100%, 60 vs 90%, and 59 vs 95%, respectively, p < 0.001. The sensitivity, specificity, PPV, NPV, and accuracy of CECT for metastatic staging were 73, 87, 69, 89, and 83%, whereas the accuracy of PET/CT was 100%, p = 0.01. By correctly characterizing unsuspected distant lesions, PET/CT could change management in 19% of patients.

CONCLUSION

FDG-PET/CT can contribute to change in the management in almost one of every five patients of PA evaluated with the standard investigations during the initial staging.

Colorectal cancer staging: comparison of whole-body PET/CT and PET/MR

PURPOSE

Correct staging is imperative for colorectal cancer (CRC) since it influences both prognosis and management. Several imaging methods are used for this purpose, with variable performance. Positron emission tomography-magnetic resonance (PET/MR) is an innovative imaging technique recently employed for clinical application. The present study was undertaken to compare the staging accuracy of whole-body positron emission tomography-computed tomography (PET/CT) with whole-body PET/MR in patients with both newly diagnosed and treated colorectal cancer.

METHODS

Twenty-six patients, who underwent same day whole-body (WB) PET/CT and WB-PET/MR, were evaluated. PET/CT and PET/MR studies were interpreted by consensus by a radiologist and a nuclear medicine physician. Correlations with prior imaging and follow-up studies were used as the reference standard. Correct staging was compared between methods using McNemar's Chi square test.

RESULTS

The two methods were in agreement and correct for 18/26 (69%) patients, and in agreement and incorrect for one patient (3.8%). PET/MR and PET/CT stages for the remaining 7/26 patients (27%) were discordant, with PET/MR staging being correct in all seven cases. PET/MR significantly outperformed PET/CT overall for accurate staging (P = 0.02).

CONCLUSION

PET/MR outperformed PET/CT in CRC staging. PET/MR might allow accurate local and distant staging of CRC patients during both at the time of diagnosis and during follow-up.

The Practice of Using Contrast Sonography for the Differential Diagnosis of Liver Neoplasms

Purpose: to improve the differential diagnosis of benign liver rumors and the liver metastasis of colorectal cancer with the ultrasound using contrast sonography.

Materials and methods.There were evaluated 92 patients with liver neoplasms (44 (47.8%) women and 48 (52.2%) men) age 41 to 83, with a mean age of 62.8 ± 2.64. Ultrasound exam was carried out in three stages: I stage – liver ultrasound in B-mode, II stage – ultrasound in B-mode with addition of color Doppler imaging and power Doppler scanning, III stage – contrast liver sonography employing the contrast agent SonoVue (Bracco Imaging SpA, Milan, Italy). According to the results of the examination the patients were either surgically treated if there were indications, or the nature of the neoplasm was verified via the needle biopsy. Thus the patients formed two groups: I group (n = 35 (38.0%) – patients with benign liver neoplasms: cavernous hemangiomas – 17, hepatocellular adenomas – 3, focal modular hyperplasia of the liver – 5; II group (n = 57 (62.0%) – patients with metastasis of colorectal cancer.

Results.With the use of the ultrasound in B-mode with addition of color Doppler imaging and power Doppler scanning in patients from group I (n = 35) with benign tumors of the liver – bilobar involvement in 2 cases, right lobe involvement in 28 cases, left lobe involvement in 5 cases. There were found both solitary (in 33 cases) and multiple (in 2 cases) neoplasms ranging from 2.5– 4.5 cm to conglomerates of 8–17 cm in diameter. In group II (n = 57), in patients with colorectal cancer metastasis who had an ultrasound examination in B-mode with addition of color Doppler imaging and power Doppler scanning, bilobar metastatic (91.2%) involvement of the liver prevailed over the monolobar, notably right lobe (84.21%) involvement was more frequent. Multiple metastasis were encountered more often (89.5%) then solitary. At the moment of metastatic liver disease discovery the size of the tumor nodules was over 5 cm in diameter in 33 (57.8%) patients. According to the results of contrast sonography in patients of group I (n = 35) with benign tumors of the liver, there was detected a prolonged enhancement of the neoplasm in the arterial, portal and delayed phases of enhancement. In patients of group II (n = 57) with metastasis of colorectal cancer to the liver, in the end of arterial phase there was noted a “washing out” of the contrast agent by 16th second – in 36 (63.1%) of the patients, by 23th se cond – in 17 (29.8%) and by the 26th second – in 4 (7.0%) of the patients. In portal and delayed phase of the enhancement all of the group II patients (100%) at the site of the metastasis there were located anechogenic round foci.

Conclusions. 1. Complex 3-stage ultrasound examination (B-mode, color Doppler imaging and power Doppler scanning, contrast sonography) of the liver neoplasms allows to get a more detailed information and differentiate benign and metastatic disease of the liver; 2. During contrast sonography the benign liver tumors “keep” the contrast gent during the arterial, portal and delayed enhancement phases, but with metastasis in liver the contrast agent gets “washed out” already in the arterial phase of enhancement.

Added Value of Contrast-Enhanced Ultrasound on Biopsies of Focal Hepatic Lesions Invisible on Fusion Imaging Guidance

Objective

To assess whether contrast-enhanced ultrasonography (CEUS) with Sonazoid can improve the lesion conspicuity and feasibility of percutaneous biopsies for focal hepatic lesions invisible on fusion imaging of real-time ultrasonography (US) with computed tomography/magnetic resonance images, and evaluate its impact on clinical decision making.

Materials and Methods

The Institutional Review Board approved this retrospective study. Between June 2013 and January 2015, 711 US-guided percutaneous biopsies were performed for focal hepatic lesions. Biopsies were performed using CEUS for guidance if lesions were invisible on fusion imaging. We retrospectively evaluated the number of target lesions initially invisible on fusion imaging that became visible after applying CEUS, using a 4-point scale. Technical success rates of biopsies were evaluated based on histopathological results. In addition, the occurrence of changes in clinical decision making was assessed.

Results

Among 711 patients, 16 patients (2.3%) were included in the study. The median size of target lesions was 1.1 cm (range, 0.5–1.9 cm) in pre-procedural imaging. After CEUS, 15 of 16 (93.8%) focal hepatic lesions were visualized. The conspicuity score was significantly increased after adding CEUS, as compared to that on fusion imaging (p < 0.001). The technical success rate of biopsy was 87.6% (14/16). After biopsy, there were changes in clinical decision making for 11 of 16 patients (68.8%).

Conclusion

The addition of CEUS could improve the conspicuity of focal hepatic lesions invisible on fusion imaging. This dual guidance using CEUS and fusion imaging may affect patient management via changes in clinical decision-making.

PET/CT in paediatric malignancies - An update

¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a well-established imaging modality in adult oncological practice. Its role in childhood malignancies needs to be discussed as paediatric malignancies differ from adults in tumor subtypes and they have different tumor biology and FDG uptake patterns. This is also compounded by smaller body mass, dosimetric restrictions, and physiological factors that can affect the FDG uptake. It calls for careful planning of the PET study, preparing the child, the parents, and expertise of nuclear physicians in reporting pediatric positron emission tomography/computed tomography (PET/CT) studies. In a broad perspective, FDG-PET/CT has been used in staging, assessment of therapy response, identifying metastases and as a follow-up tool in a wide variety of pediatric malignancies. This review outlines the role of PET/CT in childhood malignancies other than hematological malignancies such as lymphoma and leukemia.

The role of surgery in the therapeutic approach of gastric cancer liver metastases

Gastric cancer (GC) currently prevails as the second cause of death by malignancy worldwide. Estimations suggest that 35 % of affected patients appear with synchronous distant metastases. The vast majority of patients present with hepatic metastatic disease, sometimes accompanied by synchronous peritoneal and lung dissemination. The disease mostly remains asymptomatic at an early stage, with few reported cases of incidental abdominal discomfort. As the cancer advances, symptoms such as nausea or vomiting arise, along with indigestion and dysphagia, blood loss in the form of melena or hematemesis, as well as anorexia and weight loss. Having spread to the liver, it also causes jaundice due to hepatomegaly and general inanition. Despite recent research on the therapeutic strategies against GC metastatic disease, surgical resection appears the only potentially curative approach. Unfortunately, the majority of patients are not eligible to undergo surgical intervention. With regard to treatment modalities of the advanced stage disease, the role of metastasectomy is still debatable and quite unclear, while prolonged survival was succeeded only under certain specific circumstances. Systemic chemotherapy remains however another option, as well as local management in the form of cryotherapy, radiofrequency ablation, or transcatheter arterial chemoembolization. The aims of this review were to evaluate the results of surgical treatment for metastatic GC with special reference to the extent of its histological spread and to present the recent literature in order to provide an update on the current concepts of advanced surgical management of this entity. Relevant publications in the last two decades are briefly reviewed.

Current evidence for the diagnostic value of gadoxetic acid-enhanced magnetic resonance imaging for liver metastasis

A variety of imaging techniques, including ultrasonography (US), multidetector computed tomography (MDCT), magnetic resonance imaging (MRI) and positron emission tomography combined with CT scan (PET/CT), are available for diagnosis and treatment planning in liver metastasis. Contrast-enhanced MDCT is a relatively non-invasive, widely available and standardized method for hepatic work-up. Gadoxetic acid (gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid; EOB Primovist®]) is a recently developed liver-specific hepatobiliary MR contrast agent that offers both dynamic imaging as well as liver-specific static hepatocyte imaging, referred to as the hepatobiliary phase. Following contrast injection, this technique reveals dynamic vascular phases (arterial, portal venous and delayed phases), in addition to the hepatobiliary phase upon uptake by functional hepatocytes. The overall sensitivity of gadoxetic acid-enhanced MRI was significantly higher than that of contrast-enhanced CT. Specifically, the higher sensitivity of gadoxetic acid-enhanced MRI was observed in lesions smaller than 1 cm in diameter. Gadoxetic acid-enhanced MRI is considered an extremely useful tool for the diagnosis of liver metastases. Future studies will focus on diagnostic algorithms involving combinations of modalities such as MRI, MDCT and/or (18) F-fluorodeoxyglucose PET/CT, which may impact the treatment plan for these patients.

Preoperative Use of PET/CT in Patients With Colorectal and Gastric Cancer and Its Impact on Treatment Decision Making

The advantages of primary positron emission tomography–computed tomography (PET-CT) evaluation of both cancers needs to be clarified. This study aimed to investigate the efficacy of PET-CT compared with computed tomography (CT) in preoperative evaluation of colorectal and gastric cancer patients, and to determine its effects on treatment decision-making. We prospectively evaluated patients who presented with both types of cancer in our clinic between September 2008 and June 2010, using PET-CT and CT. We compared the results with histopathologic findings and determined the changing treatment strategies. In detecting local lymph node positivity, for colorectal cancer patients the sensitivity of PET-CT was 30% and that of CT was 20%; the specificities were the same (100%). For gastric cancer patients, the sensitivity of PET-CT was 38.9% and that of CT was 22%; the specificities were 100% and 83%, respectively. In detecting metastasis, for colorectal cancer patients the sensitivity of PET-CT was 80% and that of CT was 50%; the specificities were similar (100% versus 95%). For gastric cancer patients, the sensitivity of PET-CT was 72% and that of CT was 34%; the specificities were similar (95% versus 90%). In detecting liver metastasis, for colorectal cancer patients the sensitivity of PET was 75% and that of CT was 50%; the specificities were similar (100% versus 95%). For gastric cancer patients, the sensitivity of PET-CT was 57% and that of CT was 28%; the specificities were similar (95% versus 91%). PET-CT findings altered treatment decisions in 16% of patients (n = 10; 9 gastric cancer and 1 colorectal cancer). A high rate of treatment strategy alteration in gastric cancers was seen with PET-CT; its usage is preferred in colorectal cancer staging only for high-risk patients and those with equivocal findings.

Advantages of L-3-[(18)F] fluoro-alpha-methyl tyrosine over 2-[(18)F]-fluoro-2-deoxyglucose in detecting liver metastasis during positron emission tomography scan

Purpose

We aimed to assess the usefulness of positron emission tomography (PET) using the amino acid tracer L-3-[18F] fluoro-alpha-methyl tyrosine (FAMT) in detecting metastatic liver lesions compared with 2-[18F]-fluoro-2-deoxyglucose (FDG).

Methods

We included 24 patients with liver metastases who underwent both FDG-PET/computed tomography (CT) and FAMT-PET/CT. Maximum standardized uptake value (SUVmax) and tumor-to-liver parenchymal (T/L) ratio were analyzed to evaluate the correlation between FDG and FAMT uptakes in metastatic liver lesions; adenocarcinoma (AC, n = 21), squamous cell carcinoma (SCC, n = 23), neuroendocrine tumor (NET, n = 9), and carcinoid tumor (CAR, n = 6).

Results

We detected 59 lesions on performing either FDG-PET or FAMT-PET. NETs had significantly lower T/L ratios for FAMT (median, 1.00; range, 0.86–1.34) compared with those for FDG (median 2.86; range 1.70–6.13, p < 0.01). CAR tumors tended to reveal lower T/L ratios for FDG (median 1.10; range 0.78–1.92) than those for FAMT (median 1.80; range 0.80–2.34). Comparison of T/L ratios of SCC and AC revealed that FAMT in the metastatic liver lesions of SCC was higher than those of AC (p < 0.05).

Conclusion

FAMT-PET could detect metastatic liver lesions from various cancers, except NET.

The 100 most cited articles investigating the radiological staging of oesophageal and junctional cancer: a bibliometric analysis

Objectives

Accurate staging of oesophageal cancer (OC) is vital. Bibliometric analysis highlights key topics and publications that have shaped understanding of a subject. The 100 most cited articles investigating radiological staging of OC are identified.

Methods

The Thomas Reuters Web of Science database with search terms including “CT, PET, EUS, oesophageal and gastro-oesophageal junction cancer” was used to identify all English language, full-script articles. The 100 most cited articles were further analysed by topic, journal, author, year and institution.

Results

A total of 5,500 eligible papers were returned. The most cited paper was Flamen et al. (n = 306), investigating the utility of positron emission tomography (PET) for the staging of patients with potentially operable OC. The most common research topic was accuracy of staging investigations (n = 63). The article with the highest citation rate (38.00), defined as the number of citations divided by the number of complete years published, was Tixier et al. investigating PET texture analysis to predict treatment response to neo-adjuvant chemo-radiotherapy, cited 114 times since publication in 2011.

Conclusion

This bibliometric analysis has identified key publications regarded as important in radiological OC staging. Articles with the highest citation rates all investigated PET imaging, suggesting this modality could be the focus of future research.

Main Messages

• This study identifies key articles that investigate radiological staging of oesophageal cancer.

• The most common topic was accuracy of staging investigations.

• The article with the highest citation rate investigated the use of texture analysis in PET images.

Focal hepatic uptake along the falciform: False positive for malignancy on 18F-FDG-PET in a lymphoma patient with superior vena cava obstruction

We present a case of focal increased intrahepatic radiotracer activity on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in a patient with lymphoma and superior vena cava (SVC) obstruction, a false positive for malignancy. Contrast-enhanced computed tomography (CT) demonstrated an enhancing region of geographic focal hypoattenuation in the liver along the falciform, corresponding to the region of increased radiotracer activity on FDG-PET, with marked narrowing of the superior vena cava and resultant collateral venous pathways to the portal vein via paraumbilical veins. CT followup demonstrated stability of the hepatic abnormality, and no lesion was evident on ultrasound, suggesting that the finding on PET-CT represented a false positive for malignancy in this patient with known SVC obstruction. In patients with SVC obstruction, radiologists should consider this phenomenon of anomalous hepatic uptake along the falciform as a source of possible false positives for malignancy on PET.

Morphologic and Functional Imaging of Non-Colorectal Liver Metastases

Liver metastases are the most frequent malignant liver lesions. Besides colorectal carcinoma, gastric carcinoma, pancreatic carcinoma, breast cancer, lung cancer, and neuroendocrine tumors are the most common entities that metastasize to the liver. The morphology of these metastases depends on the primary tumor. For morphologic and functional imaging of non-colorectal liver metastases, multiple imaging techniques such as ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography coupled with CT or MRI are available. This review summarizes morphologic and functional characteristics of different non-colorectal liver metastases.

Vascular Targeting of a Gold Nanoparticle to Breast Cancer Metastasis

The vast majority of breast cancer deaths are due to metastatic disease. Although deep tissue targeting of nanoparticles is suitable for some primary tumors, vascular targeting may be a more attractive strategy for micrometastasis. This study combined a vascular targeting strategy with the enhanced targeting capabilities of a nanoparticle to evaluate the ability of a gold nanoparticle (AuNP) to specifically target the early spread of metastatic disease. As a ligand for the vascular targeting strategy, we utilized a peptide targeting alpha(v) beta(3) integrin, which is functionally linked to the development of micrometastases at a distal site. By employing a straightforward radiolabeling method to incorporate Technetium-99m into the AuNPs, we used the high sensitivity of radionuclide imaging to monitor the longitudinal accumulation of the nanoparticles in metastatic sites. Animal and histological studies showed that vascular targeting of the nanoparticle facilitated highly accurate targeting of micrometastasis in the 4T1 mouse model of breast cancer metastasis using radionuclide imaging and a low dose of the nanoparticle. Because of the efficient targeting scheme, 14% of the injected AuNP deposited at metastatic sites in the lungs within 60 min after injection, indicating that the vascular bed of metastasis is a viable target site for nanoparticles.

Non-invasive diagnostic imaging of colorectal liver metastases

Colorectal cancer is one of the few malignant tumors in which synchronous or metachronous liver metastases [colorectal liver metastases (CRLMs)] may be treated with surgery. It has been demonstrated that resection of CRLMs improves the long-term prognosis. On the other hand, patients with un-resectable CRLMs may benefit from chemotherapy alone or in addition to liver-directed therapies. The choice of the most appropriate therapeutic management of CRLMs depends mostly on the diagnostic imaging. Nowadays, multiple non-invasive imaging modalities are available and those have a pivotal role in the workup of patients with CRLMs. Although extensive research has been performed with regards to the diagnostic performance of ultrasonography, computed tomography, positron emission tomography and magnetic resonance for the detection of CRLMs, the optimal imaging strategies for staging and follow up are still to be established. This largely due to the progressive technological and pharmacological advances which are constantly improving the accuracy of each imaging modality. This review describes the non-invasive imaging approaches of CRLMs reporting the technical features, the clinical indications, the advantages and the potential limitations of each modality, as well as including some information on the development of new imaging modalities, the role of new contrast media and the feasibility of using parametric image analysis as diagnostic marker of presence of CRLMs.