Susceptibility-weighted imaging for the noncontrast evaluation of hepatocellular carcinoma: a prospective study with histopathologic correlation

Intravoxel incoherent motion and enhanced T2*-weighted angiography for preoperative prediction of microvascular invasion in hepatocellular carcinoma

Objective

To investigate the value of the combined application of intravoxel incoherent motion (IVIM) and enhanced T2*-weighted angiography (ESWAN) for preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC).

Materials and methods

76 patients with pathologically confirmed HCC were retrospectively enrolled and divided into the MVI-positive group (n=26) and MVI-negative group (n=50). Conventional MRI, IVIM, and ESWAN sequences were performed. Three region of interests (ROIs) were placed on the maximum axial slice of the lesion on D, D*, and f maps derived from IVIM sequence, and R2* map derived from ESWAN sequence, and intratumoral susceptibility signal (ITSS) from the phase map derived from ESWAN sequence was also automatically measured. Receiver operating characteristic (ROC) curves were drawn to evaluate the ability for predicting MVI. Univariate and multivariate logistic regression were used to screen independent risk predictors in clinical and imaging information. The Delong's test was used to compare the differences between the area under curves (AUCs).

Results

The D and D* values of MVI-negative group were significantly higher than those of MVI-positive group (P=0.038, and P=0.023), which in MVI-negative group were 0.892×10-3 (0.760×10-3, 1.303×10-3) mm2/s and 0.055 (0.025, 0.100) mm2/s, and in MVI-positive group were 0.591×10-3 (0.372×10-3, 0.824×10-3) mm2/s and 0.028 (0.006, 0.050)mm2/s, respectively. The R2* and ITSS values of MVI-negative group were significantly lower than those of MVI-positive group (P=0.034, and P=0.005), which in MVI-negative group were 29.290 (23.117, 35.228) Hz and 0.146 (0.086, 0.236), and in MVI-positive group were 43.696 (34.914, 58.083) Hz and 0.199 (0.155, 0.245), respectively. After univariate and multivariate analyses, only AFP (odds ratio, 0.183; 95% CI, 0.041-0.823; P = 0.027) was the independent risk factor for predicting the status of MVI. The AUCs of AFP, D, D*, R2*, and ITSS for prediction of MVI were 0.652, 0.739, 0.707, 0.798, and 0.657, respectively. The AUCs of IVIM (D+D*), ESWAN (R2*+ITSS), and combination (D+D*+R2*+ITSS) for predicting MVI were 0.772, 0.800, and, 0.855, respectively. When IVIM combined with ESWAN, the performance was improved with a sensitivity of 73.1% and a specificity of 92.0% (cut-off value: 0.502) and the AUC was significantly higher than AFP (P=0.001), D (P=0.038), D* (P=0.023), R2* (P=0.034), and ITSS (P=0.005).

Conclusion

The IVIM and ESWAN parameters showed good efficacy in prediction of MVI in patients with HCC. The combination of IVIM and ESWAN may be useful for noninvasive prediction of MVI before clinical operation.

Prediction of microvascular invasion in hepatocellular carcinoma patients with MRI radiomics based on susceptibility weighted imaging and T2-weighted imaging

BACKGROUND

The accurate identification of microvascular invasion (MVI) in patients with hepatocellular carcinoma (HCC) is of great clinical importance.

PURPOSE

To develop a radiomics nomogram based on susceptibility-weighted imaging (SWI) and T2-weighted imaging (T2WI) for predicting MVI in early-stage (Barcelona Clinic Liver Cancer stages 0 and A) HCC patients.

MATERIALS AND METHODS

A prospective cohort of 189 participants with HCC was included for model training and testing, and an additional 34 participants were enrolled for external validation. ITK-SNAP was used to manually segment the tumour, and PyRadiomics was used to extract radiomic features from the SWI and T2W images. Variance filtering, student's t test, least absolute shrinkage and selection operator regression and random forest (RF) were applied to select meaningful features. Four machine learning classifiers, including K-nearest neighbour, RF, logistic regression and support vector machine-based models, were established. Independent clinical and radiological risk factors were also determined to establish a clinical model. The best radiomics and clinical models were further evaluated in the validation set. In addition, a nomogram was constructed from the radiomic model and independent clinical factors. Diagnostic efficacy was evaluated by receiver operating characteristic curve analysis with fivefold cross-validation.

RESULTS

AFP levels greater than 400 ng/mL [odds ratio (OR) 2.50; 95% confidence interval (CI) 1.239-5.047], tumour diameter greater than 5 cm (OR 2.39; 95% CI 1.178-4.839), and absence of pseudocapsule (OR 2.053; 95% CI 1.007-4.202) were found to be independent risk factors for MVI. The areas under the curve (AUCs) of the best radiomic model were 1.000 and 0.882 in the training and testing cohorts, respectively, while those of the clinical model were 0.688 and 0.6691. In the validation set, the radiomic model achieved better diagnostic performance (AUC = 0.888) than the clinical model (AUC = 0.602). The combination of clinical factors and the radiomic model yielded a nomogram with the best diagnostic performance (AUC = 0.948).

CONCLUSION

SWI and T2WI-derived radiomic features are valuable for noninvasively and accurately identifying MVI in early-stage HCC. Furthermore, the integration of radiomics and clinical factors yielded a predictive nomogram with satisfactory diagnostic performance and potential clinical benefits.

Detection of tumour boundary in metastatic liver disease with 2D multibreath-hold susceptibility-weighted imaging

PURPOSE

To investigate the feasibility of susceptibility weighted imaging (SWI) in detecting tumour boundaries in metastatic liver disease (MLD) without contrast agent, and whether SWI can provide pathophysiologic information for preoperative evaluation.

METHODS

Thirty patients with MLD underwent tumour resection. All patients underwent conventional MRI (T1-weighted and T2-weighted imaging), contrast-enhanced (CE) MRI and multibreath-hold 2D SWI. The conspicuity of the tumour boundary was assessed using a 4-grade scale. The detection rate of tumour boundaries and areas were reviewed and measured. The longest dimension was used to estimate the tumour size from the MR image. The conspicuity of the tumour boundary and area were compared using a nonparametric multi-group comparison (Friedman M). The McNemar test was applied to examine differences in the detection rate of tumour boundaries.

RESULTS

Among four different MRI sequences, SWI exhibited increased conspicuity of the tumour boundary than the conventional MRI (P < 0.001). SWI (91.8%) and CE-MRI (64.4%) exhibited higher detection rates of the tumour boundary than T1WI and T2WI (6.8% and 12.3% respectively). Longer tumour maximum diameters were measured with SWI (29.1 ± 17.2 mm) and CE-MRI (28.2 ± 16.8) compared to conventional MRI (P < 0.05).

CONCLUSION

2D multibreath-hold SWI enables enhanced noninvasive detection of tumour boundaries in patients with MLD compared with conventional MRI and CE-MRI without using an exogenous contrast agent. SWI has the potential to become a preoperative assessment standard that complements conventional MRI.

Study on clinical application of susceptibility weighted imaging ombined with diffusion weighted imaging in patients with Liver Cirrhosis complicated with small Hepatocellular Carcinoma

Objectives

To evaluate the clinical value of susceptibility weighted imaging (SWI) combined with diffusion weighted imaging (DWI) in patients with liver cirrhosis complicated with small hepatocellular carcinoma (SHCC).

Methods

A total of 40 patients with liver cirrhosis and 44 nodules were treated with conventional nuclear magnetic scanning (T1WI, T2WI) and SWI combined with DWI; the results were judged by two senior physicians; the t test, χ² test, rank sum test, and other methods were used for contrastive analysis of the pathological results of different scanning methods after operation or puncture.

Results

Contrast analysis of the different MRI scanning methods and pathological results showed that among the 32 nodules of small hepatocellular carcinoma, 24 cases were diagnosed by conventional MRI, with the coincidence rate being 75%, 30 cases were diagnosed by SWI DWI, with the coincidence rate being 96%; significant difference was found between the two groups (p=0. 04). Significant differences were found in the specificity, sensitivity and accuracy of different scanning methods in the diagnosis of small hepatocellular carcinoma (specificity, accuracy, p=0.04; sensitivity p=0.01). The SWI of small hepatocellular carcinoma nodules showed hyperintensity, and the degree of iron deposition was low. Significant difference was found between small hepatocellular carcinoma nodules and other nodules (comparison of SWI signal degree, p=0.01; comparison of iron deposition degree, p=0.00).

Conclusion

The SWI of small hepatocellular carcinoma nodules showed hyperintensity, and the degree of iron deposition was low. The coincidence rate of SWI+DWI scanning is higher than that of conventional scanning methods in the diagnosis of small hepatocellular carcinoma, and the difference in specificity, sensitivity and accuracy has obvious advantages. SWI+DWI scanning can improve the detection rate of liver cirrhosis complicated with small hepatocellular carcinoma.

The peritumoral hypointense rim around hepatocellular carcinoma on T2*-weighted magnetic resonance imaging: radiologic-pathologic correlation

BACKGROUND

A peritumoral hypointense rim (PTHR) is sometimes observed around hepatocellular carcinoma (HCC) on T2*-weighted images (T2*WIs). We aimed to investigate the association between the PTHR and histopathologic findings on T2*WIs.

METHODS

We assessed the presence of a PTHR on T2*WIs in 39 pathologically proven HCCs from April 2012 to December 2013. Prussian blue staining was performed, and iron deposition was evaluated by semiquantitative and quantitative methods. Optical density was used in the quantitative methods. The associations between a PTHR on T2*WI and histopathologic peritumoral or background liver iron deposition were analyzed.

RESULTS

A PTHR on T2*WI was observed in 23 of 39 (59%) HCCs. There was no significant difference in the histopathologic fibrous capsule findings (P = 0.394). In the semiquantitative methods, both peritumoral and background liver iron deposition grade were significantly higher in HCCs with a PTHR compared with HCCs without a PTHR (P < 0.001). The mean optical density in HCCs with a PTHR was significantly higher compared with HCCs without a PTHR, in the quantitative peritumoral (42,244.1 ± 20,854.9 vs. 18,739.1 ± 12,258.7, respectively; P < 0.001) and background liver iron deposition analyses (35,554.7 ± 19,854.8 vs. 17,292.4 ± 11,605.8, respectively; P < 0.001). Tumor size (P = 0.005), etiology (P = 0.001), and degree of fibrosis (P = 0.042) were significantly associated with the presence of a PTHR.

CONCLUSIONS

A PTHR in HCCs on T2*WIs was strongly associated with peritumoral iron deposition in the iron-deposited background liver but not with the fibrous capsule.

Radiomics Analysis of Susceptibility Weighted Imaging for Hepatocellular Carcinoma: Exploring the Correlation between Histopathology and Radiomics Features

Purpose:

No previous researches have extracted radiomics features from susceptibility weighted imaging (SWI) for biomedical applications. This research aimed to explore the correlation between histopathology of hepatocellular carcinoma (HCC) and radiomics features extracted from SWI.

Methods:

A total of 53 patients were ultimately enrolled into this retrospective study with MR examinations undertaken at a 3T scanner. About 107 radiomics features were extracted from SWI images of each patient. Then, the Spearman correlation test was performed to evaluate the correlation between the SWI-derived radiomics features and histopathologic indexes including histopathologic grade, microvascular invasion (MVI) as well as the expression status of cytokeratin 7 (CK-7), cytokeratin 19 (CK-19) and Glypican-3 (GPC-3). With SWI-derived radiomics features utilized as independent variables, four logistic regression-based diagnostic models were established for diagnosing patients with positive CK-7, CK-19, GPC-3 and high histopathologic grade, respectively. Then, receiver operating characteristic analysis was performed to evaluate the diagnostic performance.

Results:

A total of 11, 32, 18 and one SWI-derived radiomics features were significantly correlated with histopathologic grade, the expression of CK-7, the expression of CK-19 and the expression of GPC-3 (P < 0.05), respectively. None of the SWI-derived radiomics features was correlated with MVI status. The areas under the curve were 0.905, 0.837, 0.800 and 0.760 for diagnosing patients with positive CK-19, positive CK-7, high histopathologic grade and positive GPC-3.

Conclusion:

Extracting the radiomics features from SWI images was feasible to evaluate multiple histopathologic indexes of HCC.

Exploratory study of the interest of MR susceptibility-weighted imaging for the pre-operative assessment of pelvic endometriosis extent

OBJECTIVE

To evaluate the performance of magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) in the assessment of endometriosis.

MATERIAL AND METHODS

This prospective study was performed during the diagnostic step or the pre-operative assessment of endometriosis, between June 2017 and April 2018. The MRI was conducted with a 3T MRI device; protocol included T2W, T1W, with and without fat-saturation sequences completed with a SWI sequence: T2-star weighted angiography (SWAN). The diagnostic performance values of MRI and inter-observer agreement were first evaluated with a conventional MR protocol and then with the complementary SWAN sequence by 2 readers. MRI results were correlated with surgical findings in patients who underwent laparoscopy.

RESULTS

74 patients were included in the study, and among them 10 patients were treated by laparoscopy. 81% of the endometriosis lesions had signal losses on the SWAN sequence related to hemorrhagic character whereas only 52% of the lesions had T1-weighted hyperintense implants. Diagnostic performance of the MRI examination was improved by the use of the SWAN sequence compared to the conventional MR protocol (Se = 94% and Spe = 73% in complete protocol and Se = 88% and Spe = 69% in conventional protocol), especially for the involvement of torus uterinus, utero-sacral ligament and retro-cervical site. An excellent interobserver agreement (қ-value = 0,94) was noted between the two readers.

CONCLUSION

SWI can improve the diagnostic accuracy of MRI by allowing the detection of hemorrhagic character of endometriosis lesions.

Performance of Magnetic Resonance Susceptibility-Weighted Imaging for Detection of Calcifications in Patients With Hepatic Echinococcosis

OBJECTIVE

We evaluated the performance of susceptibility-weighted imaging (SWI) for identification of hepatic calcifications in alveolar echinococcosis and cystic echinococcosis.

METHODS

The SWI images of 58 lesions in 40 patients (age, 49 ± 14 y) with alveolar echinococcosis (n = 22) or cystic echinococcosis (n = 18) were reviewed for calcifications. First, calcifications were suggested by visual assessment. Second, ratios of minimum intralesional intensity and mean lumbar muscle intensity were recorded. Computed tomography (CT) served as the criterion standard.

RESULTS

Thirty-seven lesions showed calcifications on CT. Susceptibility-weighted imaging provided a sensitivity of 89.2% (95% confidence interval [CI], 50.1-75.7) and a specificity of 57.1% (95% CI, 34.4-77.4) for calcifications detected by visual assessment. Receiver operating characteristic curves demonstrated a sensitivity of 67.6% and a specificity of 85.0% for an intensity ratio of 0.61. A specificity of 100% (95% CI, 80.8-100) and a sensitivity of 84.5% (95% CI, 67.3-93.2) were achieved by SWI for calcifications with a density greater than 184 HU in CT.

CONCLUSIONS

Identification of hepatic calcifications is possible with SWI. Susceptibility-weighted imaging offers the potential to reduce the need for of CT imaging for evaluation of echinococcosis.

Magnetic resonance imaging ancillary features used in Liver Imaging Reporting and Data System: An illustrative review

Hepatocellular carcinoma (HCC) usually develops in the setting of chronic liver disease. In the adequate clinical context, both multiphasic contrast-enhanced CT and magnetic resonance imaging are non-invasive modalities that allow accurate diagnosis and staging of HCC, although the latter demonstrates greater sensitivity and specificity. Imaging criteria for HCC diagnosis rely on hemodynamic features such as hyperenhancement in the arterial phase and washout in the portal or equilibrium phase. However, imaging performance drops considerably for small (< 20 mm) nodules because their tendency to exhibit atypical enhancement patterns. In order to improve accuracy in the diagnosis and staging of HCC, particularly in cases of atypical nodules, ancillary features, i.e., imaging characteristics that modify the likelihood of HCC, have been described and incorporated into clinical reports, especially in Liver Imaging Reporting and Data System. In this paper, ancillary imaging features will be reviewed and illustrated.

Use of Susceptibility-Weighted Imaging (SWI) in the Detection of Brain Hemorrhagic Metastases from Breast Cancer and Melanoma

PURPOSE

Susceptibility-weighted imaging (SWI) has significantly increased our sensitivity in detecting hemorrhagic brain lesions. We sought to explore the prevalence of intratumoral hemorrhage as detected by SWI in brain metastases from melanoma and breast cancer.

METHODS

Lesions with a size of 0.1 cm were categorized as micrometastases, whereas larger lesions were categorized as macrometastases. Susceptibility-weighted imaging findings on locations corresponding to enhancing lesions were categorized as either positive or negative based on presence/absence of signal dropout. The percentage of SWI positivity was then estimated as a function of lesion size. Two-tailed Fisher exact test was performed to examine differences in the contingency tables.

RESULTS

Magnetic resonance imaging studies from 73 patients with 1173 brain metastases, which enhanced on postcontrast T1-weighted imaging (T1WI) were selected for analysis. Of these lesions, 952 had SWI data available, and 342 of 952 were micrometastases. Only 10 of the 342 micrometastases and 410 (67.2%) of the 610 macrometastases were SWI positive (P < 0.0001). When examined by tumor type, 76.9% (melanoma) versus 55.6% (breast cancer) were SWI positive (P < 0.0001), regardless of tumor size. All melanoma lesions (8/8) and only 1 of 15 breast cancer lesions larger than 1.5 cm were SWI positive.

CONCLUSION

With the use of combined SWI and contrast-enhanced high-resolution T1 imaging, we found that presence of intratumoral brain hemorrhage is uncommon in micrometastases but common in metastases greater than 0.1 cm from breast cancer or melanoma. Large metastases commonly harbored hemorrhage, and this occurred more frequently in patients with melanoma than with breast cancer.

Detection of Endogenous Iron Reduction during Hepatocarcinogenesis at Susceptibility-Weighted MR Imaging: Value for Characterization of Hepatocellular Carcinoma and Dysplastic Nodule in Cirrhotic Liver

Objective

To investigate the value of susceptibility-weighted imaging (SWI) for characterization of hepatocellular carcinoma (HCC) and dysplastic nodule (DN).

Materials and Methods

Sixty-eight cirrhotic patients with 89 hepatocellular nodules underwent SWI. The radiological features of hepatocellular nodules on SWI were classified into three types: type A (iso- or hypointensity, and background liver siderosis), type B (hyperintensity, and background liver siderosis), or type C (hyperintensity, and no background liver siderosis). Intranodular and background liver iron content was quantified and correlated with SWI pattern. Prussian blue staining was performed to quantify intranodular and background liver iron content.

Results

Type A pattern (n = 12) contained 11 (91.7%) DNs and 1 (8.3%) HCC, Type B pattern (n = 66) comprised 1 (1.5%) DN and 65 (98.5%) HCCs (including 12 DN-HCCs and 53 overt HCCs), and type C pattern (n = 11) was exclusively seen in HCCs. The iron scores of DN-HCCs and overt HCCs were significantly lower than those of background livers [(0.091±0.30) VS (2.18±0.87), P = 0.000; (0.11±0.41) VS (2.16±0.97), P = 0.000; respectively]. There was no significant difference between iron scores of DNs and those of background livers [(1.92±0.29) VS (2.17±039), P = 0.191]. For lesion-based and patient-based analysis of HCCs (DN-HCCs and overt HCCs), type B pattern showed a sensitivity, specificity, accuracy, positive predicative value (PPV), and negative predicative value (NPV) of 84.4% and 84.4%, 91.7% and 75%, 85.4% and 83.8%, 98.5% and 98.2%, 47.8% and 23.1%, respectively.

Conclusion

SWI can provide valuable information for characterization of HCC and DN based on endogenous iron reduction during hepatocarcinogenesis.

Susceptibility-Weighted Imaging Manifestations in the Brain of Wilson's Disease Patients

Purpose

It is well known that patients with Wilson’s disease (WD) suffer copper metabolism disorder. However, recent studies point to an additional iron metabolism disorder in WD patients. The purpose of our study was to examine susceptibility-weighted imaging (SWI) manifestations of WD in the brains of WD patients.

Methods

A total of 33 patients with WD and 18 normal controls underwent conventional MRI (Magnetic resonance imaging) and SWI. The phase values were measured on SWI-filtered phase images of the bilateral head of the caudate nuclei, globus pallidus, putamen, thalamus, substantia nigra, and red nucleus. Student’s t-tests were used to compare the phase values between WD groups and normal controls.

Results

The mean phase values for the bilateral head of the caudate nuclei, globus pallidus, putamen, thalamus, substantia nigra, and red nucleus were significantly lower than those in the control group (P < 0.001), and bilateral putamen was most strongly affected.

Conclusions

There is paramagnetic mineralization deposition in brain gray nuclei of WD patients and SWI is an effective method to evaluate these structures.