Differentiation of well-differentiated hepatocellular carcinomas from other hepatocellular nodules in cirrhotic liver: value of SPIO-enhanced MR imaging at 3.0 Tesla

Magnetic Relaxation Switching Assay Using IFNα-2b-Conjugated Superparamagnetic Nanoparticles for Anti-Interferon Antibody Detection

Type I interferons, particularly IFNα-2b, play essential roles in eliciting adaptive and innate immune responses, being implicated in the pathogenesis of various diseases, including cancer, and autoimmune and infectious diseases. Therefore, the development of a highly sensitive platform for analysis of either IFNα-2b or anti-IFNα-2b antibodies is of high importance to improve the diagnosis of various pathologies associated with the IFNα-2b disbalance. For evaluation of the anti-IFNα-2b antibody level, we have synthesized superparamagnetic iron oxide nanoparticles (SPIONs) coupled with the recombinant human IFNα-2b protein (SPIONs@IFNα-2b). Employing a magnetic relaxation switching assay (MRSw)-based nanosensor, we detected picomolar concentrations (0.36 pg/mL) of anti-INFα-2b antibodies. The high sensitivity of the real-time antibodies' detection was ensured by the specificity of immune responses and the maintenance of resonance conditions for water spins by choosing a high-frequency filling of short radio-frequency pulses of the generator. The formation of a complex of the SPIONs@IFNα-2b nanoparticles with the anti-INFα-2b antibodies led to a cascade process of the formation of nanoparticle clusters, which was further enhanced by exposure to a strong (7.1 T) homogenous magnetic field. Obtained magnetic conjugates exhibited high negative MR contrast-enhancing properties (as shown by NMR studies) that were also preserved when particles were administered in vivo. Thus, we observed a 1.2-fold decrease of the T2 relaxation time in the liver following administration of magnetic conjugates as compared to the control. In conclusion, the developed MRSw assay based on SPIONs@IFNα-2b nanoparticles represents an alternative immunological probe for the estimation of anti-IFNα-2b antibodies that could be further employed in clinical studies.

IONPs-Based Medical Imaging in Cancer Care: Moving Beyond Traditional Diagnosis and Therapeutic Assessment

Cancer-related burden of morbidity and mortality is rapidly rising worldwide. Medical imaging plays an important role in every phase of cancer management, including diagnosis, staging, treatment planning and evaluation. Iron oxide nanoparticles (IONPs) could serve as contrast agents or labeling agents to enhance the identification and visualization of pathological tissues as well as target cells. Multimodal or multifunctional imaging can be easily acquired by modifying IONPs with other imaging agents or functional groups, allowing the accessibility of combined imaging techniques and providing more comprehensive information for cancer care. To date, IONPs-enhanced medical imaging has gained intensive application in early diagnosis, monitoring treatment as well as guiding radio-frequency ablation, sentinel lymph node dissection, radiotherapy and hyperthermia therapy. Besides, IONPs mediated imaging is also capable of promoting the development of anti-cancer nanomedicines through identifying patients potentially sensitive to nanotherapeutics. Based on versatile imaging modes and application fields, this review highlights and summarizes recent research advances of IONPs-based medical imaging in cancer management. Besides, currently existing challenges are also discussed to provide perspectives and advices for the future development of IONPs-based imaging in cancer management.

Visibility of focal liver lesions: Comparison between kupffer phase of CEUS with sonazoid and hepatobiliary phase of gadoxetic acid-enhanced MRI

BACKGROUND

To investigate the agreement between Kupffer phase of Sonazoid contrast-enhanced sonography (CEUS) and hepatobiliary phase of gadoxetic acid-enhanced MRI in the evaluation of focal liver lesions (FLLs).

METHODS

One hundred fifty-four FLLs in 154 patients who underwent both Sonazoid CEUS and gadoxetic acid-enhanced liver MRI were included in this retrospective study. FLL visibility on the Kupffer-phase images was graded as one (invisible or isoenhancing), two (vaguely visible or vaguely hypoenhancing), or three (clearly visible or clearly hypoenhancing), and that on the hepatobiliary-phase images of MRI was graded as one (invisible or hyper/isointense), two (vaguely visible or weakly hypointense), or three (clearly visible or strongly hypointense). Pairwise comparison of lesion visibility between the two modalities was performed, and intermodality agreement was assessed.

RESULTS

On Kupffer-phase CEUS, 31 (20.1%) lesions were invisible, 17 (11.1%) were vaguely visible, and 106 (68.9%) were clearly visible. On the hepatobiliary-phase MRI, 9 (5.9%) lesions were invisible, 45 (29.2%) were vaguely visible, and 100 (64.9%) were clearly visible. Overall, lesion visibility scores were not significantly different between the two modalities (p = 0.121), but the visibility was significantly better on MRI in smaller lesions. Twenty-eight lesions (18.2%) showed discrepancy in the visibility on CEUS and MRI, and most of the cases (89.7%) were lesions that were invisible on CEUS but visible on MRI.

CONCLUSIONS

The overall visibility of FLLs was comparable between the Kupffer phase of Sonazoid-CEUS and the hepatobiliary-phase images of gadoxetic acid-enhanced MRI, with a discrepancy between the two modalities in 18% of the cases. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:542-550, 2017.

Functional imaging of hepatocellular carcinoma

Imaging plays a key role in the clinical management of hepatocellular carcinoma (HCC), but conventional imaging techniques have limited sensitivity in visualizing small tumors and assessing response to locoregional treatments and sorafenib. Functional imaging techniques allow visualization of organ and tumor physiology. Assessment of functional characteristics of tissue, such as metabolism, proliferation and stiffness, may overcome some of the limitations of structural imaging. In particular, novel molecular imaging agents offer a potential tool for early diagnosis of HCC, and radiomics may aid in response assessment and generate prognostic models. Further prospective research is warranted to evaluate emerging techniques and their cost-effectiveness in the context of HCC in order to improve detection and response assessment.

Superparamagnetic iron oxide-enhanced magnetic resonance imaging for focal hepatic lesions: Systematic review and meta-analysis

AIM: To evaluate the performance of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) in the detection and characterization of focal hepatic lesions (FHLs).

METHODS: This meta-analysis compared relevant studies that were identified by searching PubMed, EMBASE, and the Cochrane Library databases for articles published between January 1988 and September 2014 and that met the following criteria: (1) SPIO-enhanced MRI was conducted to identify FHLs and data were sufficient for pooled analysis using Meta-DiSc 1.4; (2) hepatocellular carcinomas (HCCs) were differentiated from other FHLs; (3) well-differentiated HCCs (WD-HCCs) were contradistinguished from dysplastic nodules; and (4) WD-HCCs were compared with moderately and poorly differentiated HCCs (MD- and PD-HCCs, respectively).

RESULTS: The data obtained from 15 eligible studies yielded a sensitivity of 85% and a specificity of 78% for differentiating between HCCs and other FHLs. The sensitivity was unchanged and the specificity was increased to 87% when non-HCC malignancies were excluded. Comparative analyses between WD-HCCs and MD- and PD-HCCs from seven studies showed a sensitivity of 98% and a specificity of 50% for the diagnosis of MD- and PD-HCCs, and the area under the summary receiver operating characteristics (sROC) curve was 0.97. A comparison between WD-HCCs and dysplastic nodules revealed a sensitivity of 50% and a specificity of 92% for the diagnosis of WD-HCCs and the area under the sROC curve was 0.80.

CONCLUSION: SPIO-enhanced MRI is useful in differentiating between HCCs and other FHLs.

Radiological diagnosis of hepatocellular carcinoma

Diagnosis of hepatocellular carcinoma (HCC) still remains a challenging issue. In the setting of liver cirrhosis, international guidelines have set the noninvasive criteria for HCC diagnosis, represented by the detection of contrast hyperenhancement in the arterial phase (wash-in) and hypoenhancement in the portal or delayed phase (wash-out) with dynamic multi-detector computer tomography or magnetic resonance (MR) imaging. Although highly specific, this typical enhancement pattern has relatively low sensitivity, since approximately one-third of HCC nodules are characterized by atypical enhancement patterns. In atypical HCC nodules larger than 1 cm, the majority of international guidelines recommend liver biopsy. However, there is an increasing interest in exploiting new noninvasive diagnostic tools, to increase the sensitivity of radiological diagnosis of HCC. Diffusion-weighted MR imaging and MR hepatobiliary contrast agents may represent useful tools for the detection and characterization of borderline hypovascular lesions by providing functional information such as water molecule motion in diffusion-weighted imaging and residual hepatobiliary function, which can be impaired early during the course of hepatocarcinogenesis. Also, dual-energy computed tomography (CT) represents an interesting new CT technology that could increase detectability and conspicuity of hypervascular lesions, thus possibly improving CT sensitivity in small HCCs. However, more data and further developments are needed to verify the usefulness of these new technologies in the diagnosis of HCC and to translate these recent advances into clinical practice.

Enhancement patterns of hepatocellular carcinomas on multiphasicmultidetector row CT: comparison with pathological differentiation

OBJECTIVE

The objective of this study was to determine the incidence of typical and atypical enhancement patterns of hepatocellular carcinomas (HCCs) on multiphasic multidetector row CT (MDCT) and to correlate the enhancement patterns and morphological image findings of HCC with the degree of tumour differentiation.

METHODS

MDCT images of 217 patients with 243 surgically proven HCCs were evaluated through consensus reading by two radiologists. Our MDCT protocol was composed of precontrast, arterial, portal and delayed phases. The reviewers analysed the CT images for degree of attenuation; relative timing of washout; presence of dysmorphic intratumoral vessels, aneurysms and necrosis; tumour size; tumour margin; presence of pseudocapsule; intratumoral heterogeneity; and determined enhancement pattern. The imaging features were correlated with tumour differentiation using Fisher's exact test or the χ(2) test.

RESULTS

Among 243 HCCs, 137 (56.4%) showed the typical enhancement pattern of HCC, which is arterial enhancement and washout on portal or equilibrium phase images. In the arterial phase, 190 of 243 (78.2%) HCCs showed hypervascularity, with approximately three quarters of poorly differentiated (PD) (34 of 45, 75.6%) and moderately differentiated (MD) HCCs (92 of 123, 74.8%) showing washout during the portal or delayed phases, vs only 50% of well-differentiated (WD) HCCs (11 of 22; p<0.048). The presence of intratumoral vessels and aneurysms, tumour necrosis, attenuation of precontrast, the relative timing of washout, intratumoral attenuation heterogeneity, tumour margin and tumour size were correlated with the pathological differentiation of HCCs (p<0.05).

CONCLUSION

A typical enhancement of HCCs on MDCT was not unusual (43.6%) and WD and PD HCCs account for most of the atypical enhancement patterns. Early washout favoured MD and PD HCCs rather than WD HCCs, whereas in our study the presence of intratumoral aneurysm was a highly specific finding for PD HCC.

Negatively charged superparamagnetic iron oxide nanoparticles: a new blood-pooling magnetic resonance contrast agent

PURPOSE

Our purpose was to investigate the utility of superparamagnetic iron-oxide nanoparticles (SPIO) as a blood-pooling contrast agent at magnetic resonance imaging (MRI).

MATERIALS AND METHODS

We studied four contrast agents: carboxymethyl-diethylaminoethyl dextran magnetite SPIO (CMEADM-S, diameter 54 nm), negatively charged CMEADM ultrasmall SPIO (CMEADM-U, 32 nm), alkali-treated dextran magnetite SPIO (ATDM-S, 55 nm), and ATDM ultrasmall SPIO (ATDM-U, 28 nm) carrying a neutral charge. Each contrast agent (80 μmol/kg) was injected intraperitoneally into apolipoprotein E (apoE) mice and the tissue iron concentration was measured 30-, 60-, 180-, and 300-min later by nuclear MR. For MR angiographic (MRA) evaluation, we injected the agents into the auricular vein of four groups of 15 rabbits. Immediately and 30-, 60-, 180-, and 300-min later, three rabbits from each group were subjected to MRI. The organ/background signal ratio (SR) was calculated. Statistical analyses were performed with Tukey's honestly significant difference (HSD) test.

RESULTS

At 60 and 180 min, blood-iron concentration of CMEADM-U was significantly different from other contrast agents. In the abdominal aorta and inferior vena cava, SR of CMEADM-U was higher at 180 and 300 min than of the other contrast agents. In the thoracic aorta, there was no difference in SR at 300 min between CMEADM-U and CMEADM-S.

CONCLUSION

Negatively charged SPIO nanoparticles may be useful as a blood-pooling contrast agent.

New paradigm for management of hepatocellular carcinoma by imaging

Based on recent clinical practice guidelines, imaging is largely replacing pathology as the preferred diagnostic method for determination of hepatocellular carcinoma (HCC). A variety of imaging modalities, including ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), nuclear medicine, and angiography, are currently used to examine patients with chronic liver disease and suspected HCC. Advancements in imaging techniques such as perfusion imaging, diffusion imaging, and elastography along with the development of new contrast media will further improve the ability to detect and characterize HCC. Early diagnosis of HCC is essential for prompt treatment, which may in turn improve prognosis. Considering the process of hepatocarcinogenesis, it is important to evaluate sequential changes via imaging which would help to differentiate HCC from premalignant or benign lesions. Recent innovations including multiphasic examinations, high-resolution imaging, and the increased functional capabilities available with contrast-enhanced US, multidetector row CT, and MRI have raised the standards for HCC diagnosis. Although hemodynamic features of nodules in the cirrhotic liver remain the main diagnostic criterion, newly developed cellspecific contrast agents have shown great possibilities for improved HCC diagnosis and may overcome the diagnostic dilemma associated with small or borderline hepatocellular lesions. In the 20th century paradigm of medical imaging, radiological diagnosis was based on morphological characteristics, but in the 21st century, a paradigm shift to include biomedical, physiological, functional, and genetic imaging is needed. A multidisciplinary team approach is necessary to foster an integrated approach to HCC imaging. By developing and combining new imaging modalities, all phases of HCC patient care, including screening, diagnosis, treatment, and therapy, can be dramatically improved.

Imaging study of early hepatocellular carcinoma: usefulness of gadoxetic acid-enhanced MR imaging

PURPOSE

To describe imaging findings of early hepatocellular carcinoma (HCC) at gadoxetic acid-enhanced magnetic resonance (MR) imaging, dynamic contrast material-enhanced computed tomography (CT), CT during arterial portography (CTAP), and CT during hepatic arteriography (CTHA) and to compare the diagnostic performance of each modality for small (≤ 2 cm) HCC.

MATERIALS AND METHODS

The institute ethics committee deemed study approval unnecessary. One hundred eight resected small lesions in 64 patients were diagnosed as a dysplastic nodule (DN) (n = 12), progressed HCC (n = 66), or early HCC (n = 30). All but two patients underwent all imaging examinations. The imaging characteristics of the lesions with each modality were determined. To evaluate the diagnostic performance of the modalities, two radiologists graded the presence of HCC with use of a five-point confidence scale. The area under the receiver operating characteristic curve (A(z)), sensitivity, and specificity of each modality were compared.

RESULTS

The imaging features that are statistically significant for differentiating an early HCC from a DN include fat-containing lesions at dual-echo T1-weighted MR imaging (seen in 16 of the 30 early HCCs and none of the DNs), low attenuation at unenhanced CT (seen in 13 of the 30 early HCCs and none of the DNs), low attenuation at CTAP (seen in 11 of the 30 early HCCs and none of the DNs), and low signal intensity at hepatocyte phase gadoxetic acid-enhanced MR imaging (seen in 29 of the 30 early HCCs and none of the DNs). The diagnostic performance of gadoxetic acid-enhanced MR imaging (A(z), 0.98 and 0.99) was significantly greater than that of contrast-enhanced CT (A(z), 0.87) and CTHA-CTAP (A(z), 0.85 and 0.86) owing to its significantly higher sensitivity (P < .001).

CONCLUSION

Gadoxetic acid-enhanced MR imaging is the most useful imaging technique for evaluating small HCC, including early HCC.

Contribution of diffusion-weighted magnetic resonance imaging in the characterization of hepatocellular carcinomas and dysplastic nodules in cirrhotic liver

OBJECTIVES

To evaluate the diagnostic value of diffusion-weighted magnetic resonance imaging (DWI) for the characterization of hepatocellular carcinoma (HCC) and dysplastic nodule (DN) in cirrhotic liver, compared with contrast material-enhanced magnetic resonance imaging (CE-MRI).

METHODS

A total of 54 patients with 40 HCC and 19 DN lesions were included in our study, and all lesions were histopathologically confirmed. All lesions were evaluated with CE-MRI, and breath-hold DWI was performed with b = 500 s/mm. The signal intensity (SI) of the lesions were classified as low, iso-, slightly high, and strongly high SI compared with that of the surrounding liver parenchyma on DWI for qualitative assessment. Apparent diffusion coefficients (ADCs) and lesion-to-liver ADC ratio of HCCs and DNs were measured and compared by using the Mann-Whitney U test. The lesions were characterized with the use of CE-MRI criteria and DWI, respectively. Receiver operating characteristic analysis was performed to assess the diagnostic value of DWI, CE-MRI, and these techniques combined in the differentiation of HCCs from DNs.

RESULTS

In the qualitative analysis, among 40 HCCs, 39 (97.5%) had slightly high or strongly high SI on DWI, and 1 (2.5%) had low SI; only 4 (21.5%) of 19 DNs had slightly high SI, and 15 (78.95%) had iso-SI or low SI. The mean (SD) ADC and ADC ratio for HCCs (1.28 x 10 [0.25] mm/s and 0.88 [0.15], respectively) were significantly lower (P < 0.01 and P < 0.001, respectively) than those for DNs (1.53 x 10 [0.33] mm/s and 1.00 [0.08], respectively). The area, Az, under the receiver operating characteristic curve for the SI feature, the ADC ratio, and the ADCs based on the diagnosis of HCC versus DN were 0.88, 0.81, and 0.68, respectively. When the slightly high SI of lesion with a cutoff ADC ratio less than 0.92 was applied as a criterion, the Az, the sensitivity, the specificity, and the accuracy of DWI for the diagnosis of HCC versus DN were 0.81, 67.50%, 94.74%, and 76.27%, respectively. The corresponding Az, sensitivity, specificity, and accuracy of CE-MRI were 0.70, 82.50%, 57.89%, and 74.58%, respectively. Combined DWI plus CE-MRI had 0.91 Az, 97.50% sensitivity, and 93.22% accuracy, which increased significantly compared with those of CE-MRI alone.

CONCLUSIONS

Diffusion-weighted MRI can provide additional information to differentiate HCC from DN. Combined with CE-MRI, DWI allows improved characterization of HCC versus DN in cirrhotic liver.

Additional value of SPIO-enhanced MR imaging for the noninvasive imaging diagnosis of hepatocellular carcinoma in cirrhotic liver

OBJECTIVES

The purpose of this study is to determine whether adding superparamagnetic iron oxide (SPIO)-enhanced MR images to the 2 dynamic imaging modalities, triphasic CT scan and dynamic MR imaging (MRI), improves the diagnosis of hepatocellular carcinomas (HCCs) compared with the noninvasive diagnosis provided by the European Society of Study of the Liver (EASL) criteria.

MATERIALS AND METHODS

This retrospective study included 108 patients with 152 histologically confirmed hepatocellular nodules, ie, 28 dysplastic nodules and 124 HCCs. Of the 124 HCCs, 79 were larger than 2 cm in diameter, 34 were between 1 to 2 cm, and 11 were less than 1 cm. The reviewers retrospectively analyzed by consensus the hypervascularity of the nodules on both dynamic CT and MR images as well as their signal intensity on SPIO-enhanced images. Sensitivity, specificity, and diagnostic accuracy were assessed based on the EASL noninvasive diagnostic criteria for HCC and SPIO-combined EASL criteria.

RESULTS

Seventeen (14%) of 124 HCCs were hypovascular HCC according to both imaging modalities, and hypovascular HCC was more frequently seen in the subgroup of HCC < or = 2 cm in diameter. A significant improvement in the sensitivity (78% to 96%) for diagnosing HCCs larger than 2 cm in diameter, was achieved by adding SPIO-enhanced MR images to 2 dynamic studies compared with the noninvasive diagnosis according to the EASL criteria (P < 0.01). When the EASL criteria were applied to the 34 HCCs of 1 to 2 cm in diameter, 21 lesions (62%) were correctly diagnosed using the EASL criteria and 29 lesions (85%) according to the SPIO-combined EASL criteria.

CONCLUSIONS

Adding SPIO-enhanced MR images to the dynamic imaging modalities, including triphasic CT and dynamic MRI, improves the noninvasive diagnosis of HCCs compared with using only the EASL criteria, especially when attempting to diagnose hypovascular or slightly hypervascular HCCs. As these images combine information regarding the function or deficit of Kupffer cells within the hepatic nodules with vascularity information, combining sequentially acquired SPIO-enhanced MRI with dynamic MRI could be considered to be the single-step imaging modality with a high degree of accuracy in the diagnostic work-up of small HCCs.

Detection of hepatic metastases by superparamagnetic iron oxide-enhanced MR imaging: prospective comparison between 1.5-T and 3.0-T images in the same patients

OBJECTIVE

To prospectively compare the diagnostic performance of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging at 3.0 T and 1.5 T for detection of hepatic metastases.

METHODS

A total of 28 patients (18 men, 10 women; mean age, 61 years) with 80 hepatic metastases were prospectively examined by SPIO-enhanced MR imaging at 3.0 T and 1.5 T. T1-weighted gradient-recalled-echo (GRE) images, T2*-weighted GRE images and T2-weighted fast spin-echo (SE) images were acquired. The tumour-to-liver contrast-to-noise ratio (CNR) of the lesions was calculated. Three observers independently reviewed each image. Image artefacts and overall image quality were analysed, sensitivity and positive predictive value for the detection of hepatic metastases were calculated, and diagnostic accuracy using the receiver-operating characteristics (ROC) method was evaluated.

RESULTS

The tumour-to-liver CNRs were significantly higher at 3.0 T. Chemical shift and motion artefact were more severe, and overall image quality was worse on T2-weighted fast SE images at 3.0 T. Overall image quality of the two systems was similar on T1-weighted GRE images and T2*-weighted GRE images. Sensitivity and area under the ROC curve for the 3.0-T image sets were significantly higher.

CONCLUSION

SPIO-enhanced MR imaging at 3.0 T provided better diagnostic performance for detection of hepatic metastases than 1.5 T.