Evidence of diagnostic enhancement pattern in hepatocellular carcinoma nodules ≤2 cm according to the AASLD/EASL revised criteria

Purpose

To define the percentage of small (≤2 cm) hepatocellular carcinoma (HCC) nodules showing the diagnostic enhancement pattern at CEUS, computed tomography (CT), and gadobenate dimeglumine (Gd-BOPTA)—enhanced magnetic resonance (MR) imaging.

Methods

42 cirrhotic patients (26 male, 16 female; 67 ± 12 years) with 46 biopsy-proven HCCs ≤2 cm were included. Each HCC was scanned by CEUS, contrast-enhanced CT, and Gd-BOPTA-enhanced MR imaging. Nodule enhancement was evaluated by two readers. Independent analysis was followed by consensual analysis and the proportion of HCCs with the diagnostic enhancement pattern (nodule hyperenhancing on hepatic arterial phase and hypoenhancing on portal venous—late phase) on CEUS, CT, and MR imaging was compared by chi-square test.

Results

Very good inter-reader agreement was observed on hepatic arterial phase and portal venous—late phase: CEUS, k = 0.89 and 0.85; CT, k = 0.91 and 0.88; MR imaging, k = 0.96 and 0.94. CEUS and CT did not differ in the percentage of HCC nodules with a diagnostic enhancement pattern (18/46 and 16/46; P = 0.66), while MR imaging revealed the diagnostic pattern in higher percentage of nodules (29/46; P = 0.012) in comparison to CEUS and CT.

Conclusions

CEUS and contrast-enhanced CT did not differ in the percentage of small HCC nodules with diagnostic enhancement pattern, while Gd-BOPTA-enhanced MR imaging revealed the diagnostic pattern in a higher nodule number in comparison to CEUS and CT.     

Dynamic enhancing vascular pattern of intrahepatic peripheral cholangiocarcinoma on contrast-enhanced ultrasound: the influence of chronic hepatitis and cirrhosis

Purpose

To analyse the dynamic enhancing features by real-time contrast-enhanced ultrasound (CEUS) of intrahepatic peripheral cholangiocarcinoma (ICC) in patients with chronic hepatitis and cirrhosis.

Materials and methods

CEUS was performed by using contrast pulse sequencing (CPS) imaging with mechanical index of <0.2 after injection of 2.4 mL of contrast agent. CEUS images of histologically confirmed ICC in 54 patents (15 patents with chronic hepatitis B, 16 patents with cirrhosis, and 23 patents with normal underlying liver) were analyzed.

Results

Heterogeneous hyperenhancement was more frequently identified in ICC with chronic hepatitis (9 of 15, 60.0%, p = 0.000) and cirrhosis (8 of 16, 50.0%, p = 0.010) than in patients with normal liver (6 of 23, 26.1%) during arterial phase. The majority of ICC in patients with normal liver displayed peripheral hyperenhancement (13 of 23, 56.5%), than in patients with chronic hepatitis (4 of 15, 26.7%, p = 0.000) and cirrhosis (5 of 16, 31.3%, p = 0.001). Intense contrast uptake during the arterial phase (heterogeneous hyperenhancement or global hyperenhancement) followed by washout in venous phases was more frequently displayed in ICC patients with chronic hepatitis (11 of 15, 73.3%, p = 0.000) and in patients with cirrhosis (11 of 16, 68.8%, p = 0.000) than in ICC patients with normal underlying liver (8 of 23, 34.8%).

Conclusion

The enhancing vascular pattern of ICC on CEUS in patients with chronic hepatitis and cirrhosis is different from that in ICC without underlying liver disease. The enhancing vascular pattern is indistinguishable from HCC on CEUS in most ICC patients with chronic hepatitis or cirrhosis.     

Diffusion-weighted MRI: a useful technique to discriminate benign versus malignant ovarian surface epithelial tumors with solid and cystic components

Purpose

To evaluate differences in apparent diffusion coefficient (ADC) values for the solid component of benign and malignant ovarian surface epithelial tumors with the goal of differentiating benign versus malignant ovarian tumors preoperatively.

Materials and methods

A total of 127 patients with 131 pelvic masses identified by ultrasound between January 2006 and January 2011 were enrolled in this study. 46 patients were diagnosed with benign tumors, and 85 patients were diagnosed with malignant pathologies. For all of the patients, routine spin-echo MRI and diffusion-weighted imaging were performed. ADC values were determined for all of the masses, and the mean ADC values for the benign and malignant tumors were analyzed using Student’s t test. A P value <0.05 was considered statistically significant.

Results

Mean ADC values associated with malignant ovarian surface epithelial tumors were significantly lower than the mean ADC values of the benign tumors. In addition, the range of ADC values associated with a 95% confidence interval did not overlap between the two groups. ROC analysis indicated that a cutoff ADC value of 1.25 × 10^?3 mm²/s was associated with 90.1% sensitivity and 89.9% specificity.

Conclusion

ADC values determined from 1.5 T MR DWI of benign and malignant ovarian masses were found to be significantly different.     

Central vascular structures as a characteristic finding of regenerative nodules using hepatobiliary phase gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid-enhanced MRI and arterial dominant phase contrast-enhanced US

Objective

We investigated the characteristic findings of regenerative nodules (RNs) for differentiating early hepatocellular carcinoma (HCC) from high-grade dysplastic nodules (HGDNs) using magnetic resonance imaging (MRI) with gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA; EOB-MRI) and contrast-enhanced ultrasonography (CEUS) in patients with chronic liver disease.

Subjects and methods

Pathologically confirmed lesions (100 early HCCs, 7 HGDNs, and 20 RNs with a maximum diameter of more than 1 cm and mean maximal diameters of 15.5, 15.1, and 14.8 mm, respectively) were enrolled in this retrospective study. The signal intensities of these lesions during the hepatobiliary phase of EOB-MRI were investigated, and findings characteristic of RNs using this modality were also evaluated using CEUS.

Results

Ninety-eight of the 100 early HCCs that were hypo-intense (n = 95), iso-intense (n = 2), or hyper-intense (n = 1) and the seven HGDNs that were hypo-intense (n = 6) or hyper-intense (n = 1) during the hepatobiliary phase of EOB-MRI exhibited centripetal vessels during the arterial dominant phase of CEUS, although one early HCC that was hypo-intense exhibited both centrifugal and centripetal vessels. Eighteen of the 20 RNs and one early HCC that were hyper-intense with a small central hypo-intensity and the remaining two RNs that were hyper-intense on EOB-MRI exhibited centrifugal vessels during the arterial dominant phase of CEUS. The small central hypo-intense area corresponded to central vascular structures in the lesion, such as the hepatic artery and portal vein running from the center to the periphery, when viewed using CEUS.

Conclusion

Central vascular structures may be a characteristic finding of RNs when observed during the hepatobiliary phase of EOB-MRI and the arterial dominant phase of CEUS.

     

Differential diagnosis between benign and malignant ulcers: 320-row CT virtual gastroscopy

Purpose

This study aims to assess the diagnostic accuracy of virtual gastroscopy obtained by 320-row computed tomography (CT) examination in differentiating benign from malignant gastric ulcers (GUs).

Materials and methods

49 patients (30 M, 19 F, mean age 58.6) with endoscopic and histological diagnosis of GU underwent CT examination. A hypotonizing drug was administered and gastric walls were distended by air in order to perform virtual endoscopy. Based on morphological features, GUs were subdivided into benign or malignant forms by two blinded radiologists. Interobserver agreement was evaluated using Cohen??s kappa (k) test. CT results were then compared with endoscopic and histological findings, having the latter as the reference standard.

Results

Thirty-five out of 49 patients (71%) were affected by malignant ulcers, while in the remaining 14 cases diagnosis of benign GU was made. Virtual gastroscopy showed diagnostic accuracy, sensitivity, and specificity values of 94%, 91%, and 100%, respectively, in differentiating benign from malignant ulcers. Almost perfect agreement between the two readers was found (k?=?0.86).

Conclusion

CT virtual gastroscopy improves the identification of GUs and allows differentiating benign from malignant forms.     

Improved outcome of percutaneous radiofrequency ablation in renal cell carcinoma: a retrospective study of intraoperative contrast-enhanced ultrasonography in 73 patients

Objectives

To evaluate the impact of contrast-enhanced ultrasonography (CEUS) during percutaneous radiofrequency ablation (PRFA) procedure in renal cell carcinoma (RCC).

Methods

From January 2008 to July 2010, 73 patients with sporadic unilateral RCC were enrolled to our study (57 men and 16 women, age range: 37–78 years, mean age 57.9 years). The diameter of the tumor was 1.7–5.8, 3.4 cm on average. The patients were divided into two groups depending on the intraoperative ultrasonography type: CEUS group and conventional ultrasound group. Patients in CEUS group received CEUS before insertion of the electrode, and the second CEUS was performed right after the initial ablation to dynamically evaluate the images. If there was highly suspicious residue, additional ablation and repeated CEUS were applied. Patients in the conventional ultrasound group received PRFA guided by gray-scale ultrasound. All of these patients received contrast-enhanced computed tomography (CT) examination 7 days after the procedure (patients in CEUS group received CEUS conducted with each CT scan), with subsequent CT and CEUS assessment at 3, 6, and every 6 months thereafter.

Results

The mean follow-up period was 22 months (range: 12–42 months). All tumors were biopsied before RFA. The local tumor control rate was 94.6% (35/37) in the CEUS group and 86.1% (31/36) in the conventional ultrasound group (P < 0.05); the cancer-specific survival rate and the overall survival rate were 100%. The post-RFA (12 months) mean GFR levels were 84.7 ± 27.5 mL/min/1.73 m² (P > 0.05, compared with pre-GFR: 86.4 ± 26.2 mL/min/1.73 m²) in the CEUS group and 81.9 ± 22.8 mL/min/1.73 m² (P > 0.05, compared with pre-GFR: 83.5 ± 23.7 mL/min/1.73 m²) in the conventional ultrasound group.

Conclusion

Intraoperative CEUS can “real-time” monitor the ablated area during PRFA procedure. This technique can help to achieve a higher success rate compared with conventional ultrasound. No impact of intraoperative CEUS has been found on GFR level.     

MR imaging in the characterization of small renal masses

Objective

The aim of our study was to evaluate the effectiveness of MR imaging for the characterization of small (<2 cm) renal lesions described as indeterminate on prior US or CT

Materials and methods

Sixty-three small renal masses in 51 patients considered indeterminate on prior ultrasound or CT scans were included in the study. A retrospective evaluation of the examinations was performed independently by two body magnetic resonance imaging (MRI) radiologists who were unaware of the final diagnosis. A 3-point confidence scale (1: benign, 2: indeterminate, and 3: malignant) was established to determine the level of suspicion for malignancy. Interobserver agreement was determined with a weighted kappa statistic. The diagnosis was verified by imaging follow-up of at least 24 months (mean 60 months) in 53 lesions and by pathology in 10 lesions.

Results

MRI detected all eight malignancies in the series. There were eight malignant lesions and two benign lesions among those with pathologic follow-up. No interval growth or evidence of malignancy in the remaining 53 lesions was found for a minimum of 24 months by repeat imaging. The sensitivity, specificity, positive predictive value, and negative predictive value of MRI for differentiating benign from malignant small renal lesions were 100% (62.9–100%, 95% CI), 94.5% (84.9–98.8%, 95% CI), 72.7% (39.1–93.6%, 95% CI), and 100% (93.1–100%, 95% CI), respectively. The kappa value for interobserver agreement was 0.77 (95% CI 0.59–0.96, p-value <0.001).

Conclusion

MR imaging is an effective method for characterizing small (<2 cm) renal masses found to be indeterminate by US or CT.     

CT differentiation of 1–2-cm gallbladder polyps: benign vs malignant

Purpose

To evaluate MDCT findings of 1–2-cm sized gallbladder (GB) polyps for differentiation between benign and malignant polyps.

Methods

Institutional review board approval was obtained, and informed consent was waived. Portal venous phase CT scans of 1–2-cm sized GB polyps caused by various pathologic conditions were retrospectively reviewed by two blinded observers. Among the 36 patients identified, 21 had benign polyps with the remaining 15 having malignant polyps. Size, margin, and shape of GB polyps were evaluated. Attenuation values of the polyps, including mean attenuation, maximum attenuation, and standard deviation, were recorded. As determined by visual inspection, the degree of polyp enhancement was evaluated. Using these CT findings, each of the two radiologists assessed and recorded individual diagnostic confidence for differentiating benign versus malignant polyps on a 5-point scale. The diagnostic performance of CT was evaluated using a receiver operating characteristic curve analysis.

Results

There was no significant difference in size between benign and malignant GB polyps. Ill-defined margin and sessile morphology were significantly associated with malignant polyp. There was a significant difference in mean and maximum attenuation values between benign and malignant GB polyps. Mean standard deviation value of malignant polyps was significantly higher than that of benign polyps. All malignant polyps showed either hyperenhancement or marked hyperenhancement. A _z value for the diagnosis of malignant GB polyps was 0.905.

Conclusion

Margin, shape, and enhancement degree are helpful in differentiating between benign and malignant polyps of 1–2-cm sizes.     

Efficacy of the American Association for the Study of Liver Disease and Barcelona criteria for the diagnosis of hepatocellular carcinoma

Objectives

Dynamic contrast-enhanced CT scan and MRI are essential for preoperative diagnosis of hepatocellular carcinoma (HCC), using the established Barcelona and AASLD criteria, which have been validated in only a few reports. The aim of this study is to retrospectively assess the diagnostic performance of these criteria in diagnosing or excluding HCC in at-risk patients with histopathology confirmation.

Methods

After institutional review board approval, a HIPAA compliant study was performed. The study cohort consisted of 156 de novo hepatic nodules imaged by either dynamic contrast-enhanced CT or MRI within 90 days of histopathology. Images were retrospectively reviewed by two abdominal radiologists blinded to clinical details, and all nodules were categorized as either meeting or not meeting AASLD and Barcelona criteria. By AASLD or Barcelona criteria, HCC was defined as any nodule greater than or equal to 1 or 2 cm, respectively, with hyperenhancement relative to background liver on arterial phase and hypoenhancement relative to background liver on portal venous or delayed phases. Significant differences in cohorts were analyzed using chi squared analysis (p < 0.05).

Results

On biopsy, 141/156 (90.38%) nodules were diagnosed as HCC. The respective sensitivity, specificity, accuracy and positive predictive value of AASLD and Barcelona were 78.7% and 63.1% (sensitivity), 73.3% and 86.7% (specificity), 78.2% and 65.4% (accuracy), and 82% and 63% (positive predictive value) (p < 0.001).

Conclusions

Using established imaging criteria, up to 21.8% of presumed HCC nodules are inaccurately characterized and many small HCC nodules remain undiagnosed.     

Detection of small (≤2 cm) HCC in cirrhotic patients: added value of diffusion MR-imaging

Objectives

To evaluate the usefulness of the diffusion-weighted sequence in the detection of small (≤2 cm) hepatocellular carcinoma (HCC) in patients with cirrhosis.

Methods

Seventy cirrhotic patients with 93 HCCs underwent MR-Imaging at 1.5 T. MR acquisitions comprised unenhanced T1- and T2-weighted images and post-contrast Gd-BOPTA-enhanced T1W GRE-3D images acquired after approximately 25, 60, 180 s (dynamic phases) and 90 min (hepatobiliary phase). DWI was performed by a SSEPI sequence (b values 0, 50, 400, 800 s/mm²). Quantitative analysis was performed to establish significant difference of ADC values of benign lesions compared with that of HCC. Sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of two different protocols with and without diffusion MRI sequence were also calculated and compared each other.

Results

A good inverse correlation was found between reference standard and ADC values (ρ = ?0.688). The mean ADC value of HCC was significantly lower than the mean value of benign focal liver lesions (p < 0.0001). No significant difference was reported in term of sensitivity, specificity, PPV, NPV and diagnostic accuracy between the two datasets. A trend to a better sensitivity was found when DWI images were considered.

Conclusions

The adjunction of DWI does not significantly improve the diagnostic accuracy in the detection of small HCC.     

Differentiating hepatocellular carcinoma from dysplastic nodules at gadobenate dimeglumine-enhanced hepatobiliary-phase magnetic resonance imaging

Purpose

We evaluated whether the addition of delayed phase imaging (DPI) gadobenate dimeglumine-enhanced MRI to dynamic postcontrast imaging improves the characterization of small hepatocellular carcinoma (HCC) and the differentiation between HCC, high grade dysplastic nodules (HGDN), and low grade dysplastic nodules (LGDN).

Methods

Twenty-five cirrhotic patients with 30 nodules (16 HCC, 8 HGDNs, and 6 LGDNs; maximum size of 3 cm) were included in this retrospective study. The diagnostic reference standard was histology. All the patients underwent MRI both prior to and following intravenous administration of gadobenate dimeglumine. The lesions were classified as hypointense, isointense, hyperintense on DPI for qualitative assessment. In the quantitative analysis the relative tumor-liver contrast to noise ratio (CNR) of the lesions on DPI was calculated.

Results

All HCCs were hypointense on DPI while only 8 (57.1%) of 14 DNs were hypointense and only 1 of 6 (16.6%) LGDNs was hypointense. There was a statistically significant difference in the hypointensity on DPI between HCCs and DNs (p = 0.003) in the qualitative analysis but not in the CNR values while there was a strong statistically significant difference in the hypointensity on DPI in the qualitative (p = 0.00001) and quantitative analysis (p < 0.05) between LGDNs and the group obtained by unifying HGDNs and HCCs.

Conclusion

DPI is helpful in differentiating HCCs and HGDNs from LGDNs. Demonstration of hypointensity on DPI should raise the suspicion of HGDN or hypovascular HCC in the case of nodules with atypical dynamic pattern.     

Apparent diffusion coefficient quantification as an early imaging biomarker of response and predictor of survival following yttrium-90 radioembolization for unresectable infiltrative hepatocellular carcinoma with portal vein thrombosis

Purpose

To investigate early diffusion-weighted imaging (DWI) at 30-days post-yttrium-90 (Y-90) radioembolization as a predictor of treatment response and survival in unresectable infiltrative hepatocellular carcinoma (HCC) with portal vein thrombosis (PVT).

Materials and methods

In a prospective study, 18 consecutive patients with unresectable infiltrative HCC and PVT underwent Y-90 therapy. MR imaging was obtained pre Y-90, and at 1 and 3 months post-therapy with DWI fat-suppressed tri-directional diffusion gradient (b = 50, 400, 800 s/mm²). Response was evaluated using target mRECIST and EASL. Relative change in apparent diffusion coefficient (ADC) value of tumors was evaluated. Statistical analysis using receiver operator characteristic curves was performed. Paired t test and Pearson correlation coefficient (r) were used to assess intra- and inter-observer variability. Survival analysis was performed using Kaplan-Meier estimation and log-rank test.

Results

Mean ADC values of all HCC’s at baseline and at 30-days post-Y90 therapy was 0.86 × 10^?3 and 1.17×10^?3 mm²/s, respectively (p < 0.001). Tumors with objective response by mRECIST had significantly increased ADC value when compared to “non-responders” (1.27 vs. 1.05×10^?3 mm²/s, p = 0.002). A >30% increase in ADC value at 30-days was found to be at least 90% sensitive in predicting response at 90 days. A >30% increase in ADC value at 30-days predicted significantly prolonged survival.

Conclusion

A 30% increase in ADC value at 30-days measured post Y90 is a reproducible early imaging response biomarker predicting tumor response and prolonged survival following Y-90 therapy in infiltrative HCC with PVT.     

An Algorithm of Image Heterogeneity with Contrast-Enhanced Ultrasound in Differential Diagnosis of Solid Thyroid Nodules

Enhancement heterogeneity on contrast-enhanced ultrasonography (CEUS) is used to differentiate between benign and malignant thyroid nodules. In this study, we used an algorithm to quantify enhancement heterogeneity of solid thyroid nodules on CEUS. The heterogeneity value (HV) is calculated as standard deviation/mean intensity × 100 (using Adobe Photoshop). The heterogeneity ratio (HR) is calculated as the ratio of the HV of the nodule to that of the surrounding parenchyma. Three phases—ascending, peak and descending phases—were studied. HV values at ascending (HV_a) and peak (HV_p) phases were significantly higher in malignant nodules than in benign nodules (95.57 ± 43.87 vs. 73.06 ± 44.04, p = 0.009, and 32.53 ± 10.73 vs. 26.44 ± 8.25, p = 0.002, respectively). HR_a, HR_p and HR_d were significantly higher in malignant nodules than in benign nodules (1.93 ± 1.03 vs. 1.00 ± 0.47, p = 0.000, 1.43 ± 0.51 vs. 1.09 ± 0.28, p = 0.000, and 1.33 ± 0.40 vs. 1.08 ± 0.33, p = 0.001, respectively). HR_a achieved optimal diagnostic performance on receiver operating characteristic curve analysis. The algorithm used for assessment of image heterogeneity on CEUS examination may be a useful adjunct to conventional ultrasound for differential diagnosis of solid thyroid nodules.     

Diagnostic performance of diffusion-weighted magnetic resonance imaging in differentiating human renal lesions (benignity or malignancy): a meta-analysis

Purpose

This study aims to quantitatively evaluate the potential of diffusion-weighted magnetic resonance imaging (DW-MRI) for differentiating malignant and benign human renal lesions.

Materials and methods

A systematic literature was performed to identify previous research related to the diagnostic performance of DW-MRI for determining whether human renal lesions were benign or malignant. ADC values were extracted from normal renal tissue and different lesion types. Data were extracted to assess the diagnostic performance of DW-MRI for differentiating malignant and benign human renal lesions, as well as running threshold effect and heterogeneity.

Results

Nine publications with 11 subsets were eligible for data extraction and diagnostic performance calculation. A total of 988 apparent diffusion coefficient (ADC) measurements were included. The differences in ADC values between benign lesions (2.47 ± 0.81 × 10^?3 mm²/s) and malignant lesions (1.81 ± 0.41 × 10^?3 mm²/s) were statistically significant (P < 0.001). The diagnostic odds ratio, the overall positive, negative likelihood ratios, pooled weighted sensitivity and specificity with 95% CI were 20.05 (95% CI 12.56–32.02), 3.32 (95% CI 2.13–5.18), 0.20 (95% CI 0.15–0.27), 88% (95% CI 0.84–0.91) and 72% (95% CI 0.67–0.76), respectively. The area under the curve of the summary receiver operating characteristic was 0.90.

Conclusions

This meta-analysis indicated that DW-MRI had a relatively good diagnostic accuracy in differentiating malignant and benign human renal lesions. We preliminarily recommend that DW-MRI is performed with a maximum b value ranging from 800 to 1000 s/mm² at 3.0 T for imaging protocol, and that DW-MRI should be used with caution when the study population includes children.

     

Venous filling defects on portal venous phase CT of the abdomen and pelvis: clinical implications and positive predictive value for diagnosing deep venous thrombosis

Purpose

To determine the prevalence, resulting clinical decisions, and the positive predictive value (PPV) of venous filling defects detected on portal venous phase (PVP) CT.

Methods

Over a 3-year period, 42412 consecutive patients underwent a PVP abdominopelvic CT; of these, 348 reports mentioned a filling defect concerning for deep venous thrombosis (DVT) in the IVC, iliac, or common femoral veins. Ninety-three patients underwent a reference standard venous imaging study.

Results

The prevalence of venous filling defects in CT reports was 0.82% (n = 348). Reports worded with higher degrees of certainty were statistically more likely to result in treatment, while lower certainty was correlated with additional confirmatory imaging. The PPV for detection of DVT was 77%. The presence of peri-vascular stranding or vessel expansion increased the PPV of PVP CT to 95% and 100%, respectively.

Conclusion

While the PPV for filling defects on PVP CT was modest, it was substantially improved if peri-venous stranding or vessel expansion was present.     

Contrast-enhanced ultrasonography using Sonazoid® is useful for diagnosis of malignant ovarian tumors: comparison with Doppler ultrasound

Purpose

The purpose of this study was to assess the usefulness of Sonazoid^®-enhanced ultrasonography (US) in the diagnosis of ovarian cancer in comparison with Doppler US.

Methods

Twenty-five ovarian tumor patients who were scheduled to undergo surgery were recruited for this study. The day before the operation, each patient was evaluated with color and power Doppler and baseline US during intravenous infusion of Sonazoid. Each lesion was classified as “benign” or “malignant” on the basis of specific criteria for a Doppler signal or Sonazoid-enhanced pattern. The reference standard was the histology of surgically removed adnexal tumors.

Results

Twenty patients were diagnosed with malignant tumors (invasive cancer, n = 15; metastatic cancer, n = 1; borderline tumor, n = 4), and the remaining five were diagnosed with benign tumors. Sonazoid-enhanced US correctly depicted the presence or absence of intratumoral blood flow in all patients with an accuracy of 92 %. Color Doppler ultrasound depicted the malignancies with an accuracy of 64 %, and power Doppler ultrasound depicted them with an accuracy of 76 %.

Conclusion

Our study suggests that Sonazoid-enhanced US is superior to conventional color Doppler US for the diagnosis of malignant ovarian tumors, but not to power Doppler US. The data and their interpretation in our study should be taken with some degree of caution because of the small number of subjects. Further studies involving a larger sample size would be needed to confirm these findings.     

Small intrahepatic mass-forming cholangiocarcinoma: target sign on diffusion-weighted imaging for differentiation from hepatocellular carcinoma

Purpose

To determine the differential MRI features of small mass-forming intrahepatic cholangiocarcinoma (ICC) from hepatocellular carcinoma (HCC).

Methods

Sixty-four patients with pathologically proven small ICCs (n = 32) and HCCs (n = 32) (≤3.0 cm in diameter) who had undergone preoperative gadoxetic acid-enhanced MRI and DWI were enrolled in this study. Images were analyzed for the shape of the lesions, the presence of biliary dilatation, hyperenhancement (>50 % of the tumor volume) or rim enhancement on the arterial phase, capsular enhancement, and the presence of target appearance (a central enhancement with hypointense rim) on the hepatobiliary phase and on DWI (a central hypointense area with a peripheral hyperintense rim). Statistical significance of these findings was determined by the χ² or Fisher’s exact test. Multivariate analysis was performed to identify independent imaging findings that allow differentiation of the two diseases.

Results

Univariate analysis revealed that the following significant parameters favor ICC over HCC: lobulating shape, rim enhancement on arterial phase, target appearance on the hepatobiliary phase, and DWI (P < 0.05). Multivariate logistic regression analysis revealed that only target appearance on the DWI was a significant and independent variable predictive of ICC, as 24 ICCs (75.0 %) and one HCC (3.1 %) showed this feature (P = 0.0003).

Conclusion

A target appearance on the DWI was the most reliable imaging feature for distinguishing small mass-forming ICC from small HCC.     

Evaluation of fully automated ventilation: a randomized controlled study in post-cardiac surgery patients

Purpose

Discrepancies between the demand and availability of clinicians to care for mechanically ventilated patients can be anticipated due to an aging population and to increasing severity of illness. The use of closed-loop ventilation provides a potential solution. The aim of the study was to evaluate the safety of a fully automated ventilator.

Methods

We conducted a randomized controlled trial comparing automated ventilation (AV) and protocolized ventilation (PV) in 60 ICU patients after cardiac surgery. In the PV group, tidal volume, respiratory rate, FiO₂ and positive end-expiratory pressure (PEEP) were set according to the local hospital protocol based on currently available guidelines. In the AV group, only sex, patient height and a maximum PEEP level of 10 cmH₂O were set. The primary endpoint was the duration of ventilation within a “not acceptable” range of tidal volume. Zones of optimal, acceptable and not acceptable ventilation were based on several respiratory parameters and defined a priori.

Results

The patients were assigned equally to each group, 30 to PV and 30 to AV. The percentage of time within the predefined zones of optimal, acceptable and not acceptable ventilation were 12 %, 81 %, and 7 % respectively with PV, and 89.5 %, 10 % and 0.5 % with AV (P < 0.001). There were 148 interventions required during PV compared to only 5 interventions with AV (P < 0.001).

Conclusion

Fully AV was safe in hemodynamically stable patients immediately following cardiac surgery. In addition to a reduction in the number of interventions, the AV system maintained patients within a predefined target range of optimal ventilation.     

Unenhanced CT for the detection of renal cell carcinoma: effect of tumor size and contour type

Purpose

To evaluate effect of tumor size and contour type for the detection of renal cell carcinoma (RCC) on unenhanced CT.

Methods

This retrospective institutional review board approved study that includes 111 patients with RCC and 100 patients without RCC who underwent unenhanced CT. Two readers performed a blinded and independent review of the presence of RCC on unenhanced CT. The area under the receiver operating characteristic curves (AUC) was compared by tumor size (<3 cm: small, or ≥3 cm: large) and contour type (endophytic, mesophytic, or exophytic).

Results

For tumor size, the AUC for small RCC (0.70 and 0.78, for reader 1 and reader 2) was significantly lower than that for large RCC (0.97 and 0.99, for reader 1 and reader 2) (p < 0.001). As for contour type of tumor, the AUC for endophytic RCC (0.60 and 0.71, for reader 1 and reader 2) was significantly lower than that for mesophytic RCC (0.95 and 0.98, for reader 1 and reader 2) and exophytic RCC (0.98 and 0.99, reader 1 and reader 2) (p < 0.001).

Conclusion

On unenhanced CT, tumor size and contour type can affect the detection of RCC. While most large or exophytic RCC can be easily detected, the detection of small and endophytic RCC is highly limited.     

B-flow imaging of vascular structure for the diagnosis of liver tumor

Purpose

B-flow is a non-Doppler-based technology for visualizing blood flow and has a high spatial resolution. The aim of this study is to evaluate the blood flow information of liver tumors using B-flow in comparison with color Doppler sonography (CDS).

Methods

Seventy-nine patients with 82 hepatic nodules were studied using B-flow and CDS. The study group included 45 HCC nodules, 23 liver metastasis nodules, four intrahepatic cholangiocarcinomas (ICC), and 13 hemangiomas. The visualized vascularity and morphological findings of the hepatic tumor vessel were evaluated.

Results

B-flow showed multiple vessels in 48 nodules (58.5 %) and a single vessel in 13 nodules (15.9 %). CDS showed multiple vessels in 44 nodules (53.7 %) and a single vessel in 23 nodules (28.0 %). Multivariate analysis showed basket pattern was significant for HCC (OR 49.263; p = 0.0002), and penetrating vessel was significant for liver metastasis or ICC (OR 14.545; p < 0.0001).

Conclusion

B-flow detects hepatic tumor blood flow with sensitivity as high as that of CDS. Vascular structure information obtained using B-flow could be potentially used to diagnose liver tumors.