The application value of contrast-enhanced ultrasound in the differential diagnosis of pancreatic solid-cystic lesions

Objective

To retrospectively determine the accuracy of baseline ultrasound (BUS) and of contrast-enhanced ultrasound (CEUS) in the differential diagnosis of pancreatic solid-cystic lesions.

Methods

Fifty-four pancreatic solid-cystic lesions in 52 patients were examined with BUS and CEUS, two different seniority radiologists read the images independently, Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic value of BUS and CEUS in the diagnosis of benign or malignant pancreatic solid-cystic lesions, the diagnostic consistency between different seniority radiologists was evaluated by Kappa statistics.

Results

Among the 54 lesions, there were pancreatic cyst five cases, pancreatic pseudocyst twenty cases, pancreatic cystadenoma eight cases, pancreatic cystadenocarcinoma seven cases, intraductal papillary mucinous neoplasm of pancreas (IPMN) three cases, pancreatic carcinoma combined liquefied six cases, solid-pseudopallary tumor of pancreas (SPTP) three cases, pancreatic myopericytoma one case, pancreatic lymphangioma one case. After ROC analysis, the areas under the ROC curve (Az) were 0.752 by BUS, 0.928 by CEUS to resident radiologist, and 0.896 by BUS, 0.954 by CEUS to staff radiologist. The correct diagnosis rate of specific disease was 42.6% by BUS, 64.8% by CEUS to staff radiologist (P < 0.05), and 33.3% by BUS, 53.7% by CEUS to resident radiologist (P < 0.05). The interobserver agreement in CEUS is higher than that in BUS, the Kappa value was 0.889 ± 0.062 and 0.428 ± 0.126 respectively.

Conclusion

Compared with BUS, CEUS can significantly enhance the diagnostic rate of pancreatic solid-cystic lesions.     

Contrast enhanced ultrasound: Should it play a role in immediate evaluation of liver tumors following thermal ablation?

Purpose

To compare the accuracy of immediate CEUS with results of 24-h CEUS and MDCT in early evaluation of liver tumors following thermal ablation, using the combined results of a 3 month follow-up MDCT and CEUS as a reference standard.

Subjects and methods

From our database, we selected patients who underwent a thermal ablation immediately followed by CEUS (within 5–10 min) between February 2009 and February 2011. There were 92 patients (median age 73 years), two of whom had repeat ablation during the study period for a total of 94 tumors. Sixty tumors were treated with radiofrequency and 34 with microwave ablation. All patients underwent CEUS and CT examinations at 24 h. For patients with more than one treated tumor in the same session, the lesion imaged post-procedural and at 24-h with CEUS in all vascular phases was selected. All measurements of the necrotic zone, as an avascular zone, were performed during the portal-venous phase. Immediate post-procedural CEUS and 24 h CEUS and MDCT were blindly reviewed by two radiologists. One radiologist blindly reviewed the follow-up imaging. The mean diameters of the necrotic zone at post-procedural CEUS, and CEUS and MDCT at 24 h were compared and diagnostic accuracy to detect residual tumor calculated for each index tests compared to 3-months follow-up imaging.

Results

The mean diameter of the necrotic zone was: 29 ± 9 mm at post-procedural CEUS, 34 ± 10 mm at 24 h CEUS and 35 ± 11 mm at 24 h MDCT. Mean diameter of the necrotic zone was significantly smaller at post-procedural CEUS compared to either CEUS or MDCT at 24 h (p < 0.001 for all).With a 95% confidence interval, the sensitivity was 25% (11–47%) for immediate CEUS, 20% (8–42%) for CEUS at 24-h, and 40% (22–61%) for CT at 24-h. Specificity was 96% (89–99%) for immediate CEUS, 97% (91–99%) for CEUS at 24-h, and 97% (91–99%) for CT at 24-h.

Conclusions

Diagnostic accuracy of post-procedural CEUS in early evaluation of liver tumors following thermal ablation is comparable to both CEUS and MDCT performed at 24 h. Therefore, post-procedural CEUS can be used to detect and retreat residual viable tissue in the same ablation session.     

Application of contrast-enhanced ultrasound in the diagnosis of solid pancreatic lesions—A comparison of conventional ultrasound and contrast-enhanced CT

Objective

To explore the diagnostic value of contrast-enhanced ultrasound (CEUS) by comparison with conventional ultrasound (US) and contrast-enhanced CT (CECT) in solid pancreatic lesions.

Method

Ninety patients with solid pancreatic focal lesions were enrolled, including 36 cases of pancreatic carcinoma, 28 cases of pancreatitis, 6 cases of pancreatic neuroendocrine tumor, 12 cases of solid pseudopapillary tumor of the pancreas, 6 cases of pancreatic metastases, 1 case of cavernous hemolymphangioma and 1 case of lymphoma. US and CEUS were applied respectively for the diagnosis of a total of 90 cases of solid pancreatic lesions. The diagnostic results were scored on a 5-point scale. Results of CEUS were compared with CECT.

Results

(1) 3-score cases (undetermined) diagnosed by CEUS were obviously fewer than that of US, while the number of 1-score (definitely benign) and 5-score (definitely malignant) cases diagnosed by CEUS was significantly more than that of US. There was a significant difference in the distribution of final scores using the two methods (p < 0.001). The overall diagnostic accuracies of the 90 cases for CEUS and US were 83.33% and 44.44%, respectively, which indicated an obvious advantage for CEUS (p < 0.001). (2) The diagnostic consistency among three ultrasound doctors: the kappa values calculated for US were 0.537, 0.444 and 0.525, compared with 0.748, 0.645 and 0.795 for CEUS. The interobserver agreement for CEUS was higher than that for US. (3) The sensitivity, specificity and accuracy of the diagnosis of pancreatic carcinoma with CEUS and CECT were 91.7% and 97.2%, 87.0% and 88.9%, and 88.9% and 92.2%, respectively, while for the diagnosis of pancreatitis, the corresponding indices were 82.1% and 67.9%, 91.9% and 100%, and 88.9% and 90%, respectively, showing no significant differences (p > 0.05).

Conclusion

CEUS has obvious superiority over conventional US in the general diagnostic accuracy of solid pancreatic lesions and in the diagnostic consistency among doctors. The performances of CEUS are similar to that of CECT in the diagnosis of pancreatic carcinoma and focal pancreatitis.     

Characterisation of focal liver lesions with unenhanced and contrast enhanced low MI real time ultrasound: on-site unblinded versus off-site blinded reading

Objective

To compare on-site and blinded off-site reading of baseline ultrasound (US) and contrast enhanced ultrasound (CEUS) for classification and characterisation of focal liver lesions.

Materials and methods

99 patients (57 women and 42 men, age range 18–89 years, mean age: 59 years) with 53 malignant and 46 benign liver lesions were studied with unenhanced US followed by contrast enhanced US after injection of 2.4 ml SonoVue^® (Bracco, Milano, Italy). Image interpretation was performed on-site with clinical information available by consensus of two readers and off-site by two independent blinded readers at two different centers. Comparison of pre and post contrast scans and of the different readers was performed. Reference examinations were histology, intraoperative US, MRI or CT.

Results

Sensitivity for malignancy improved from 81/89/66% (on-site/off-site reader 1/2) before to 100/96/96% post contrast administration (p < 0.05, except for reader 1). Specificity improved from 48/48/54% on baseline US to 89/80/76% on CEUS (p < 0.05). Accuracy for specific lesion diagnosis was 62/59/50% pre and 90/77/72% post contrast (p < 0.05). Classification and characterisation post contrast were mildly inferior for off-site reading. Agreement between on-site and off-site readers of unenhanced scans was fair (κ = 0.29–0.39) while it was good for CEUS (κ = 0.63–0.79).

Conclusions

CEUS improves classification and characterisation of focal liver lesions and interobserver agreement compared to conventional US. Classification and characterisation post contrast were mildly but statistically significantly better for on-site than for off-site reading.     

Evaluation of breast lesions by contrast enhanced ultrasound: qualitative and quantitative analysis

Objective

To evaluate and compare the diagnostic performance of qualitative, quantitative and combined analysis for characterization of breast lesions in contrast enhanced ultrasound (CEUS), with histological results used as the reference standard.

Methods

Ninety-one patients with 91 breast lesions BI-RADS 3–5 at US or mammography underwent CEUS. All lesions underwent qualitative and quantitative enhancement evaluation. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of different analytical method for discrimination between benign and malignant breast lesions.

Results

Histopathologic analysis of the 91 lesions revealed 44 benign and 47 malignant. For qualitative analysis, benign and malignant lesions differ significantly in enhancement patterns (p < 0.05). Malignant lesions more often showed heterogeneous and centripetal enhancement, whereas benign lesions mainly showed homogeneous and centrifugal enhancement. The detectable rate of peripheral radial or penetrating vessels was significantly higher in malignant lesions than in benign ones (p < 0.001). For quantitative analysis, malignant lesions showed significantly higher (p = 0.031) and faster enhancement (p = 0.025) than benign ones, and its time to peak was significantly shorter (p = 0.002). The areas under the ROC curve for qualitative, quantitative and combined analysis were 0.910 (A_z1), 0.768 (A_z2) and 0.926(A_z3) respectively. The values of A_z1 and A_z3 were significantly higher than that for A_z2 (p = 0.024 and p = 0.008, respectively). But there was no significant difference between the values of A_z1 and A_z3 (p = 0.625).

Conclusions

The diagnostic performance of qualitative and combined analysis was significantly higher than that for quantitative analysis. Although quantitative analysis has the potential to differentiate benign from malignant lesions, it has not yet improved the final diagnostic accuracy.     

Can contrast-enhanced ultrasonography replace multidetector-computed tomography in the detection of liver metastases from colorectal cancer?

Purpose

To compare the sensitivity and specificity of contrast-enhanced ultrasonography (CEUS) and 4-slice multidetector-computed tomography (MDCT) in the detection of liver metastases in patients with colorectal cancer (CRC).

Materials and methods

Candidates for this prospective study were 461 consecutive patients referred to the Department of Colorectal Surgery, Aarhus University Hospital with primary or local recurrence of CRC. The patients underwent liver ultrasonography (US), CEUS, MDCT and intraoperative ultrasonography (IOUS). Fine-needle biopsy was performed on all suspicious lesions. The examinations were interpreted blindly and the combination of US, CEUS, biphasic MDCT, IOUS, follow up and biopsy was the gold standard.

Results

Three hundred and sixty-five patients were included. All patients had undergone preoperative US, CEUS and MDCT and 65.5% had received IOUS. The gold standard found liver metastases in 54 patients (14.8%). Multidetector CT found significantly more metastases than CEUS in 15 (28%) of the patients (p = 0.02). In a patient-by-patient analysis MDCT had a non-significantly higher sensitivity in the detection of liver metastases compared to CEUS (0.89 versus 0.80, p = 0.06). The specificity of CEUS (0.98) was slightly better than that of MDCT (0.94) (p = 0.02).

Conclusion

Multidetector CT found significant more metastases than CEUS, and MDCT had in patient-by-patient analysis a non-significant better sensitivity (p = 0.06) in detecting liver metastases in patients with CRC.     

Enhancement pattern of small hepatocellular carcinoma (HCC) at contrast-enhanced US (CEUS), MDCT, and MRI: intermodality agreement and comparison of diagnostic sensitivity between 2005 and 2010 American Association for the Study of Liver Diseases (AASLD) guidelines

Objective

To evaluate agreement between contrast-enhanced ultrasound (CEUS), multi-detector row computed tomography (MDCT) and magnetic resonance imaging (MRI) for the assessment of typical and atypical enhancement patterns of small hepatocellular carcinoma (HCC); and to compare diagnostic sensitivity of 2005 and 2010 American Association for the Study of Liver Diseases (AASLD) guidelines.

Materials and methods

Between January 2008 and December 2009, we included cirrhotic patients with newly diagnosed 10–20 mm HCC imaged at two contrast-enhanced imaging techniques among CEUS, MDCT, and MRI. Dynamic studies were reviewed by two radiologists to assess enhancement pattern. Percentage of cases with concordant findings and Cohen coefficient (k) were calculated. McNemar's test was used to compare sensitivity between 2005 and 2010 AASLD guidelines.

Results

There were 91 patients (69 M; 22 F; mean age, 68 years) with 96 HCCs, studied with a combination of CEUS and MDCT (n = 59), CEUS and MRI (n = 26), or MDCT and MRI (n = 11). Intermodality agreement for assessment of tumor enhancement pattern was 67% (k = 0.294, P = 0.001). Typical enhancement pattern was detected coincidentally at two imaging modalities in 50 (52%) HCCs. Sensitivity for the diagnosis of HCC increased significantly using the 2010 AASLD (81/96 (84%) vs. 50/96 (52%), P < 0.001).

Conclusions

Agreement between two imaging modalities for the detection of typical tumor enhancement pattern was reached in 52% of cases. The 2010 AASLD guidelines significantly increased the sensitivity for the diagnosis of HCC.     

Differentiating benign from malignant solid breast lesions: Combined utility of conventional ultrasound and contrast-enhanced ultrasound in comparison with magnetic resonance imaging

Objective

To prospectively evaluate the diagnostic efficacy of conventional ultrasound (US), contrast-enhanced US (CEUS), the combined use of two modalities, and magnetic resonance imaging (MRI) in the differentiation of focal solid breast lesions.

Materials and methods

61 patients with BI-RADS category 3–5 breast lesions detected at conventional US underwent CEUS and MRI. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of conventional US, CEUS, combination of two modalities and MRI for discrimination between benign and malignant breast lesions.

Results

Tissue specimens of 61 breast lesions were obtained either from surgical resection (n = 46) or from needle biopsy (n = 15). Histopathologic diagnosis revealed 28 benign and 33 malignant lesions. The diagnostic performance of conventional US and CEUS in differentiating benign from malignant breast lesions showed no significant difference (P = 0.741). The combination of two modalities significantly improved the diagnostic accuracy compared with either conventional US or CEUS alone (P = 0.031 and P = 0.012, respectively). The area under the ROC curve (A_z) value for the combined use of two modalities for discrimination between benign and malignant breast lesions was 0.94, and that for MRI was 0.91, whereas no statistical difference was found between them (P = 0.296).

Conclusion

The combined use of conventional US and CEUS has a better diagnostic performance than either method alone and displays good agreement with MRI in the differentiation capability for benign and malignant breast lesions.     

Cell apoptosis and proliferation inhibition of pancreatic cancer induced by sub-threshold focused ultrasound (FUS)

Objective

To evaluate the effects of sub-threshold focused ultrasound (FUS) sonication on the pancreatic cancer cell.

Materials and methods

The human pancreatic carcinoma cell line PaTu 8988t suspension and pancreatic carcinoma xenograft in nude mice were sonicated by FUS using sub-threshold doses. The temperature at the focus was controlled at below 60 °C. The cell apoptosis in vitro was tested by flow cytometer at 3, 6, 12, 24 and 48 h after FUS sonication. Colony formation was used to evaluate the cell growth inhibition of FUS in vitro. The tumor volume of the xenograft was measured before and after FUS sonication. Then the slides of the tumor were under hematoxylin–eosin (H&;E) staining and TdT-mediated dUTP nick end labeling (TUNEL) to evaluate the effect of FUS on pancreatic carcinoma xenograft in vivo.

Results

The maximum cell suspension temperature of the FUS sonication group was 55.8 ± 2.17 °C. The cell apoptosis rate peaked at 24 h after FUS sonication, the differences between the FUS sonication group and control group were statistically significant (P < 0.05). Colony formation rates were 50.40 ± 3.81% for the control group and 26.82 ± 2.88% for FUS sonication group (P < 0.05). For the xenografts in nude mice, the mean tumor volumes of the control group and the FUS sonication group 15 days after sonication were 1746.58 ± 312.77 mm³ and 1085.23 ± 217.13 mm³ (P < 0.05). H&;E staining and TUNEL assay showed both necrotic and apoptotic cells.

Conclusion

Sub-threshold FUS sonication could induce cell apoptosis and inhibit the proliferation of pancreatic cancer cells.     

The role of second-look ultrasound of BIRADS-3 mammary lesions detected by breast MR imaging

Objective

To asses the value of second-look ultrasound (US) for identifying BIRADS 3 (Breast Imaging Reporting Data System) mammary lesions detected by breast Magnetic Resonance imaging (MRI).

Materials and methods

From April 2008 to May 2009 330 breast MRI were performed of which 60 patients are classified as BIRADS 3. 84 lesions underwent second-look US and percutaneous vacuum biopsy Vacora system US-guided. Statistical analysis: lesions were stratified into two groups: visible on US (Group 1) and not visible on US (Group 2).The clinical impact of second-look US was studied in terms of negative predictive value (NPV).

Results

The positive predictive value (PPV) of category 3 BIRADS MRI was found to be 89%. Second look-US results detected lesions in 51% of the MRI enhancing lesions. The second look-US showed a NPV of 97%. The NPV of second look-US was significantly greater than the NPV of MRI BIRADS 3 (97% vs 89%, p < 0.05). The logistic regression analysis showed a higher number of malignant lesions in group 1 than in group 2 (7vs 2, OR 3.7, p < 0.05).

Conclusions

The second-look US permitted the correct management of subcentimetric MRI BIRADS 3 lesions not visible with conventional imaging tecniques.     

Dynamic contrast-enhanced ultrasound and transient arterial occlusion for quantification of arterial perfusion reserve in peripheral arterial disease

Objective

To quantify muscular micro-perfusion and arterial perfusion reserve in peripheral arterial disease (PAD) with dynamic contrast-enhanced ultrasound (CEUS) and transient arterial occlusion.

Materials and methods

This study had local institutional review board approval and written informed consent was obtained from all subjects. We examined the dominant lower leg of 40 PAD Fontaine stage IIb patients (mean age, 65 years) and 40 healthy volunteers (mean age, 54 years) with CEUS (7 MHz; MI, 0.28) during continuous intravenous infusion of 4.8 mL microbubbles. Transient arterial occlusion at mid-thigh level simulated physical exercise. With time–CEUS–intensity curves obtained from regions of interest within calf muscles, we derived the maximum CEUS signal after occlusion (max) and its time (t_max), slope to maximum (m), vascular response after occlusion (AUC_post), and analysed accuracy, receiver operating characteristic (ROC) curves, and correlations with ankle-brachial index (ABI) and walking distance.

Results

All parameters differed in PAD and volunteers (p < 0.014). In PAD, t_max was delayed (31.2 ± 13.6 vs. 16.7 ± 8.5 s, p < 0.0001) and negatively correlated with ankle-brachial-index (r = −0.65). m was decreased in PAD (4.3 ± 4.6 mL/s vs. 13.1 ± 8.4 mL/s, p < 0.0001) and had highest diagnostic accuracy (sensitivity/specificity, 75%/93%) for detection of diminished muscular micro-perfusion in PAD (cut-off value, m < 5∼mL/s). Discriminant analysis and ROC curves revealed m, and AUC_post as optimal parameter combination for diagnosing PAD and therefore impaired arterial perfusion reserve.

Conclusions

Dynamic CEUS with transient arterial occlusion quantifies muscular micro-perfusion and arterial perfusion reserve. The technique is accurate to diagnose PAD.     

Pancreatic neuroendocrine tumor: added value of fusion of T2-weighted imaging and high b-value diffusion-weighted imaging for tumor detection

Objectives

To investigate the added value of fusion of high b-value diffusion-weighted images (DWI) and T2-weighted (T2) MR images for the detection of pancreatic neuroendocrine tumors (PNT).

Methods

18 patients with 18 histologically proven PNT were included. Two radiologists independently and retrospectively reviewed four randomized images sets (T2+T1, DWI, T2+DWI, and DWI+T2 fusion). Lesion detection confidence level was assessed using a three grade score (no lesion; uncertain lesion and certain lesion); lesion size and signal intensity were recorded. Apparent diffusion coefficients (ADC) of tumor and adjacent pancreas were measured.

Results

Readers 1 and 2 respectively detected 14/18 and 16/18 lesions on T2+T1, 13/18 and 12/18 on DWI, 16/18 and 15/18 on T2+DWI and 17/18 and 16/18 on DWI+T2 fusion. Lesion median size was 16 mm (range: 7 mm–40 mm), 22% were hyperfunctioning (all insulinomas) and 72% were low-grade (Rindi 1). All tumors except one (with cystic component) showed lower ADC than adjacent pancreatic parenchyma. Fusion imaging had significantly better detection score by both authors (p < 0.005) and provided the higher inter-reader agreement (kappa 0.7). DWI alone had the worst score for both readers.

Conclusions

Fusion images improve the detection of PNT, especially in patients with small isointense lesions on conventional MR sequences.     

Imaging findings in phyllodes tumors of the breast

Purpose

To study the radiological appearance and pathological features of breast phyllodes tumors (PTs), and to enhance the recognition of the tumor.

Materials and methods

Clinical and imaging findings were retrospectively reviewed in 24 women with PTs confirmed by surgical pathology. All of the 24 patients had preoperative MRI and sonography, and 10 had preoperative mammography.

Results

The histologic findings were benign, borderline and malignant PTs in 16.7% (4/24), 45.8% (11/24) and 37.5% (9/24) of cases, respectively. The tumor size (p = 0.001), irregular shape on sonographic imaging (p = 0.039), internal non-enhanced septations (p = 0.009), silt-like changes in enhanced images (p = 0.006) and signal changes from T2-weighted to enhanced images on MRI (p = 0.001) correlated significantly with the histologic grade; the BI-RADS category of the MRI could reflect the PT's histologic grade with a correlation coefficient of 0.440 (p = 0.031). If the category BI-RADS ≥4a was considered to be a suspicious malignant lesion, the diagnostic accuracy of mammography, US and MRI would be 70% (7/10), 62.5% (15/24) and 95.8% (23/24), respectively.

Conclusion

The tumor size and several US and MRI findings can be used to help preoperatively determine the histologic grade of breast PTs. When a patient presents with a progressively enlarging, painless breast mass, MRI should be recommended first.     

Evaluation of tumor extent in breast cancer patients using real-time MR navigated ultrasound: Preliminary study

Objectives

To evaluate the accuracy of real-time MR navigated ultrasound (MRnav US) for tumor extent measurements in breast cancer and to investigate variables influencing the accuracy of MRnav US in comparison with US alone.

Methods

Fifty-three patients with 60 malignancies underwent preoperative breast MRI and US with or without MRI navigation. Maximum lesion sizes based on MRnav US and US alone were measured, and their relationship with the pathology was analyzed considering the differences in the clinicopathologic variables of the patients.

Results

Among 60 breast cancers, mean lesion size at initial breast US without MRI navigation and at MRI-navigated US was 19 mm and 24 mm, respectively, compared with 28 mm on the histopathology. Overall, the tumor size estimated with MRnav US was more strongly correlated with the histologic tumor size than with US alone. Accurate measurements by MRnav US were significantly more frequent in the lesions that were presented as a mass type on MRI. In addition, the accurate measurement of mass extent was improved with MRnav US in patients who had non-mass type lesions on MRI and who had undergone neoadjuvant systemic chemotherapy when compared with US alone.

Conclusion

MRnav US was more accurate for tumor extent estimation than US alone, and specific clinicopathologic variables can affect the accuracy of MRnav US.     

Evaluation of pancreatic cancer by multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging at 3.0T

Objective

To investigate the microcirculation in pancreatic cancer by pharmacokinetic analysis of multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging at 3.0 T.

Materials and methods

Multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging was performed in 40 healthy volunteers and 40 patients with pancreatic cancer proven by histopathology using an axial three-dimensions fat-saturated T1-weighted spoiled-gradient echo sequence at 3.0 T. A two compartment model with T1 correction was used to quantify the transfer constant, the rate constant of backflux from the extravascular extracellular space to the plasma and the extravascular extracellular space fractional volume in pancreatic cancer, obstructive pancreatitis distal to the malignant tumor, adjacent pancreatic tissue proximal to the tumor and normal pancreas. All parameters were statistically analyzed.

Results

Statistical differences were noticed in both the transfer constant (p = 0.000075) and the rate constant of backflux (p = 0.006) among different tissues. Both the transfer constant and the rate constant of backflux in pancreatic cancer were statistically lower than those in normal pancreas and adjacent pancreatic tissue (p < 0.05). Both the transfer constant and the rate constant of backflux in obstructive pancreatitis were statistically lower than those in normal pancreas and adjacent pancreatic tissue (p < 0.05). The extravascular extracellular space fractional volume in pancreatic cancer was statistically lager than that in normal pancreas (p = 0.002).

Conclusion

Multiple breath-hold dynamic contrast-enhanced magnetic resonance imaging offers a useful technique to evaluate the microenvironment in pancreatic cancer at 3.0 T. Compared to normal pancreas, pancreatic cancer has lower transfer constant, rate constant of backflux and larger extravascular extracellular space fractional volume.     

Application of sonoelastography: comparison of performance between mass and non-mass lesion

Objectives

The purpose of this study was to determine the performance of the conventional ultrasonography (US) and sonoelastography (SE) in three conditions of all lesions, confined to mass, and confined to non-mass lesion and to compare the performance of each modality between mass and non-mass lesion.

Materials and methods

A total 364 patients with 375 lesions were evaluated with US and subsequently SE before performing US-guided biopsy. Two radiologists retrospectively analyzed conventional US and elasticity images by consensus. The US findings were classified as mass or non-mass lesion. With final pathology as reference, in each case of all lesions, masses, and non-mass lesions, areas under the ROC curves (Az) were calculated and compared for the two techniques. The comparison of Az values between the curves for US and SE, and between the curves for mass and non-mass lesion was performed.

Results

Among 375 lesions, 104 (28%) lesions were malignant and 271 (72%) lesions were benign. 36 (9.6%) of 375 lesions were classified as non-mass lesion at US.There were statistically significant difference of performance between US and SE in cases of all lesion (p = 0.003) and mass (p = 0.023). However, there was no statistically significant difference of performance in case of non-mass lesion (p = 0.5). Comparisons of the Az values of US and SE between mass and non-mass lesions were not statistically significant (p = 0.745, p = 0.415, respectively).

Conclusion

There was no statistically significant difference of performance of US and SE between mass and non-mass lesion.     

Dynamic optical breast imaging: a novel technique to detect and characterize tumor vessels

Purpose

To prospectively determine the diagnostic accuracy of optical absorption imaging in patients with Breast Imaging Reporting and Data System (BI-RADS) 3–5 breast lesions.

Materials and methods

Forty-six patients with BI-RADS classification 3 (11%), 4 (44%) or 5 (44%) lesions, underwent a novel optical imaging examination using red light to illuminate the breast. Pressure was applied on the breast, and time-dependent curves of light absorption were recorded. Curves that consistently increased or decreased over time were classified as suspicious for malignancy. All patients underwent a core or surgical biopsy.

Results

Optical mammography showed a statistical difference in numbers of suspect pixels between benign (N = 12) and malignant (N = 35) lesions (respectively 1325 vs. 3170, P = 0.002). In this population, optical imaging had a sensitivity of 74%, specificity of 92%, and diagnostic accuracy of 79%. The optical signal did not vary according to any other parameter including breast size or density, age, hormonal status or histological type of lesions.

Conclusion

Optical imaging is a low-cost, non-invasive technique, yielding physiological information dependent on breast blood volume and oxygenation. It appears to have a good potential for discriminating benign from malignant lesions. Further studies are warranted to define its potential role in breast cancer imaging.     

Imaging manifestation of conventional and contrast-enhanced ultrasonography in percutaneous microwave ablation for the treatment of uterine fibroids

Objectives

To evaluate the image changes and the relationship between conventional ultrasonography and contrast-enhanced ultrasound (CEUS) in the perioperative period of microwave (MW) ablation for uterine fibroids; to guide clinical ablation therapy and evaluate the efficacy of MW.

Methods

Twenty-nine patients with 31 uterine fibroids were recruited in this study. All patients received conventional ultrasound as well as CEUS examination before, immediately after and 12–24 h after MW, in order to detect variations of echo and characteristics of blood supply. t-Tests were used to compare the hyperecho area on gray-scale ultrasound to immediately after ablation non-enhanced CEUS measurements, as well as to compare the immediately after ablation non-enhanced CEUS measurements to the 12–24 h after ablation measurements.

Results

Immediately after ablation, the average hyperecho area in gray-scale was 82.20 ± 72.32 cm³; the average non-enhancement area was 76.34 ± 70.63 cm³ by CEUS, showing a strong correlation (r = 0.997, P < 0.01) to the hyperecho area in gray-scale. The average non-enhancement area measured by CEUS immediately after ablation was 90.55 ± 74.41 cm³ and average 12–24 h after ablation was 98.29 ± 78.25 cm³; no statistically significant difference was detected between the two time points (P > 0.05).

Conclusions

Measurements made by hyperechoic range on gray-scale ultrasonography is strongly correlated to the no enhancement area by CEUS. The hyperechoic range on gray-scale image can represent the ablated area immediately after MW.     

Comparison of imaging characteristics between hepatic benign regenerative nodules and hepatocellular carcinomas associated with Budd-Chiari syndrome by contrast enhanced ultrasound

Purpose

To compare different imaging characteristics between hepatic benign regenerative nodules and hepatocellular carcinomas (HCCs) associated with Budd–Chiari syndrome (BCS) by contrast enhanced ultrasound (CEUS).

Materials and methods

A total of 32 chronic BCS patients (mean age, 42 years; age range, 18–59 years) with hepatic nodules who underwent CEUS were retrospectively studied. All patients had no the history of viral hepatitis. There were 23 patients with benign regenerative nodules (22 ± 9 mm; range, 8–42 mm) and 9 patients with HCCs (63 ± 21 mm; range, 26–90 mm). Lesion characteristics, including number, size, vascularization on color Doppler flow imaging, echogenicity, peripheral hypoechoic rim, and enhancement patterns in arterial, portal, and late phases on CEUS, were analyzed.

Results

There were significant differences in number and size of the lesions between two groups. No significant differences were observed in vascularity, echogenicity, and peripheral hypoechoic rim. Overall, there were significant differences in enhancement patterns in arterial, portal, and late phases between them on CEUS. Of 23 patients with benign regenerative nodules, 16 (70%) were center-to-periphery hyperenhanced and 7 patients (30%) were homogeneously hyperenhanced in arterial phase; the majority were homogeneously hyperenhanced in portal and late phases. Of 9 patients with HCCs, 8 (89%) were heterogeneously hyperenhanced in arterial phase and most of them were hypoenhanced in portal and late phases.

Conclusion

CEUS imaging characteristics of benign regenerative nodules radically differ from that of HCCs in BCS patients.     

Diagnostic performance of MRI and EUS in the differentiation of benign from malignant pancreatic cyst and cyst communication with the main duct

Purpose

To assess the diagnostic ability of MRI and EUS for differentiating benign from malignant pancreatic cyst focusing on cyst communication with pancreatic duct.

Materials and methods

During 44 months, we performed MRI on 65 pancreatic cysts. Among them, 36 patients had confirmed cyst communication with duct by ERCP or surgery and 39 patients underwent EUS. Fifty-one had proven by surgery or aspiration. Among them, 36 had confirmed malignant cysts. Two radiologists independently graded cyst communication with duct and the likelihood of malignancy. When the readers’ interpretations differed, third opinion was obtained. They also measured the size of cyst and main duct. The diagnostic performance was analyzed using the ROC curve. The Mann–Whitney U test and κ statistics were used to determine interobserver agreement.

Results

The Az of MRI and EUS for determining diagnostic performance regarding the cyst communication with duct, were 0.931 and 0.930, without statistically difference (p = 0.6). Interobserver agreement was excellent (κ = 0.81) on MRI and substantial (κ = 0.69) on EUS. The Az of MRI and EUS for assessing diagnostic performance to differentiate malignant from benign cyst, was 0.902 and 0.923, without statistically difference (p = 0.587). Interobserver agreement was excellent (κ = 0.81) on MRI and moderate (κ = 0.47) on EUS. The mean cyst size (3.98 cm + 2.74: 3.17 cm + 1.26, p = 0.327) and the duct size (5.20 mm + 3.22: 4.39 mm + 4.12, p = 0.227) showed no statistically difference between malignant and benign cysts.

Conclusion

MRI and EUS can accurately assess pancreatic cyst communication with duct and are very useful for obtaining a differential diagnosis of malignant cyst versus benign pancreatic cyst.