[Interventional sonography of the liver and kidneys]

CLINICAL/METHODICAL ISSUE

Optimization of ultrasound guided interventional procedures of the liver and kidneys using new imaging methods.

STANDARD RADIOLOGICAL METHODS

Punctures, biopsies, drainage, intraoperative ultrasound, fusion, embolization in correlation with ultrasound and other imaging methods.

METHODICAL INNOVATIONS

Real-time-sonography, contrast-enhanced ultrasound (CEUS) and fusion for planning, monitoring and postinterventional control.

PERFORMANCE

The use of CEUS enables better detection, characterization and execution of interventional procedures. Fusion facilitates detection.

ACHIEVEMENTS

The CEUS procedure is superior for detection and characterization of smaller lesions in comparison to the B scan. Fusion enables the performance of difficult interventional procedures.

PRACTICAL RECOMMENDATIONS

The B scan is the standard imaging method but CEUS and fusion could be helpful for smaller lesions.

Postoperative monitoring of local and free flaps with contrast-enhanced ultrasound (CEUS)--analysis of 112 patients

PURPOSE

Tissue defects are a common problem in trauma surgery and oncology. Flap transplantation is often the only therapy to cover such defects. Several monitoring systems are currently available but none has made it to the clinical routine. The aim of this study was to assess perfusion disturbances of local and free flaps using contrast-enhanced ultrasound (CEUS).

MATERIALS AND METHODS

112 patients were examined during the first 72 hours after operation. CEUS was performed by one experienced examiner with a linear transducer (6 - 9 MHz, LOGIQE9/GE) after a bolus injection of 2.4 ml sulfohexa-fluoride microbubbles (SonoVue®, Bracco, Italy). Retrospective vascular perfusion was quantified by evaluating the stored DICOM cine loops using the perfusion software QONTRAST® (Bracco, Italy). Over a total penetration depth of 3 cm, every centimeter was analyzed separately. 27 complications were observed. Complete flap loss was only seen in 4 cases, while 23 flaps had to undergo minor revision and survived.

RESULTS

Regarding the complete flap size, quantitative analysis showed significantly higher perfusion values in patients without complications compared to patients with complications: PEAK 16.5 vs. 10.0 (p = 0.001), TTP 32.6 vs. 22.2 (p = 0.001), RBV: 738.8 vs. 246.2 (p < 0.001), RBF 17.5 vs. 10.1 (p < 0.001) and MTT 43.1 vs. 29.5 (p = 0.001). Analysis of the correlation of the different flap types, age, sex and etiology of the tissue defect to the complication rate showed no statistical correlation.

CONCLUSION

CEUS was capable of detecting vascular disturbances after flap transplantation. TTP, RBV and MTT seem to be the most accurately parameters and are not susceptible to malfunction during measurement.

Monitoring during hepatic radiofrequency ablation (RFA): comparison of real-time ultrasound elastography (RTE) and contrast-enhanced ultrasound (CEUS): first clinical results of 25 patients

PURPOSE

To evaluate the reliability of ultrasound elastography for delineating thermal ablation defects post-radiofrequency ablation (RFA) by comparing lesion dimensions determined by real-time elastography (RTE) with the findings of contrast-enhanced ultrasound (CEUS).

MATERIALS AND METHODS

A total of 21 malignant liver tumors were percutaneously ablated using RFA. Color-coded elastography and CEUS were performed by one experienced examiner, using a 1 - 5 MHz multi-frequency convex transducer (LOGIQ E9, GE). Lesions were examined using CEUS and real-time elastography (RTE) to assess ablation defects. Measurements of lesions (long axis, short axis, and area) representing the same image plane used for elastography were taken during CEUS examination and compared to the measurements obtained from the elastograms. All measurements were performed by two independent observers.

RESULTS

A statistically significant correlation in vivo between RTE and CEUS measurements with respect to the lesion's principal axis and area (r = 0.876 long axis, r = 0.842 short axis and r = 0.889 area) was found. Inter-rater reliability assessed with the concordance correlation coefficient was substantial for all measurements (ρc ≥ 0.96) Overall, elastography slightly underestimated the lesion size, as judged by the CEUS images.

CONCLUSION

These results support that RTE could potentially be used for the routine assessment of thermal ablation therapies.

Dynamic evaluation and quantification of microvascularization during degradable starch microspheres transarterial Chemoembolisation (DSM-TACE) of HCC lesions using contrast enhanced ultrasound (CEUS): a feasibility study

PURPOSE

To evaluate the time dependent changes of microcirculation in hepatocellular carcinoma (HCC) lesions during degradable starch microsphere (DSM)-TACE using contrast enhanced ultrasound (CEUS).

MATERIALS AND METHODS

A total of 48 CEUS examinations were performed (1-5 MHz, convex probe) in 6 selected patients who underwent DSM-TACE with EmboCept®S for the treatment of HCC lesions. I.v. application of ultrasound contrast media was performed before and 24 hours post embolization. In addition i.a. contrast application was performed via the angiographic catheter right before and after the embolization and during a follow up time of 2 hours every 30 minutes. The capillary circulation of the treated HCC lesions was analyzed and quantitative perfusion analysis was performed using a perfusion software by two experienced radiologists in consensus.

RESULTS

A significantly reduced microvascularization was seen right after DSM-TACE in all cases using CEUS. The reduction of PEAK, RBV (regional blood volume) and RBF (regional blood flow) compared to preembolization values was highly significant. Mean PEAK was 34.3 ± 13.1 prior to embolization and 9.4 ± 9.1 post embolization (p < 0.001). Mean RBV was 446.5 ± 122.4 prior to embolization and 70.9 ± 23.8 post embolization (p < 0.001). The corresponding figures for RBF were 34.7 ± 13.4 prior- and 4.8 ± 3.4 post embolization (p < 0.001). During follow up a stepwise revascularization of the lesions was documented: 90 minutes post embolization perfusion parameters were not significantly different from prae-embolization values.

CONCLUSION

In this feasibility study, capillary perfusion quantification of HCC lesions after DSM-TACE could be demonstrated using CEUS. Using quantitative perfusion analysis it was possible to quantify the transient embolizing effect of DSM-TACE.

Degradable starch microspheres transarterial chemoembolisation (DSM-TACE) of HCC: Dynamic Contrast-Enhanced Ultrasonography (DCE-US) based evaluation of therapeutic efficacy using a novel perfusion software

PURPOSE

To evaluate therapeutic efficacy of degradable starch microsphere (DSM)-TACE in hepatocellular carcinoma (HCC) using Dynamic Contrast-Enhanced Ultrasonography (DCE-US) based perfusion analysis.

MATERIALS AND METHODS

A total of 60 DCE-US examinations were performed in 15 selected patients who underwent DSM-TACE with EmboCept®S for the treatment of advanced HCC. DCE-US was performed via i.v. application of ultrasound contrast media before and 24 hours post embolization. In addition DCE-US was performed with i.a. contrast application via the angiographic catheter right before and after the embolization. Microcirculation of embolized HCC lesions was quantified using a dedicated perfusion software by two experienced radiologists in consensus.

RESULTS

Significant reduction of microvascularization (PE, WiAUC and WiR) was seen right after DSM-TACE and during 24 hour follow-up. Mean PE was 342.22 ± 97.80 prior to embolization, 59.28 ± 29.74 post embolization (p = 0.019) and 18.83 ± 7.03 during follow-up (p ≤ 0.01). Mean WiAUC was 1103.21 ± 432.05 prior to embolization 267.69 ± 151.80 post embolization (p = 0.023) and 105.10 ± 44.43 during 24 hour follow-up (p ≤ 0.01). The corresponding values for WiR were 224.91 ± 57.97 prior-, 38.14 ± 18.80 post embolization (p = 0.034) and 6.97 ± 2.68 during follow up (p ≤ 0.01).

CONCLUSION

In this study, therapeutic efficacy of DSM-TACE in HCC using DCE-US based perfusion analysis could be demonstrated.

High resolution ultrasound including elastography and contrast-enhanced ultrasound (CEUS) for early detection and characterization of liver lesions in the humanized tumor mouse model

PURPOSE

In this study we investigated the sensitivity of high resolution ultrasound (HRU) in the detection of small liver tumors and its microcirculation in a humanized tumor mouse model (HTM). These mice develop a complete human immune system and human breast cancer growth in the liver which allows the investigation of antibody based immunotherapies under human like conditions.

METHOD

HTM were generated by the co-transplantation of human breast cancer cells and human hematopoietic stem cells. HRU, Doppler sonography (CCDS), contrast enhanced ultrasound (CEUS) and color-coded elastography were performed on all HTM and confirmed by histopathological assessment.

RESULTS

Using HRU and CEUS, noncystic solid liver lesions between 2 and 11 mm (mean 3.5 mm) size were detectable in HTM. Granulomatous areas were identified by B-scan imaging, showing areas of higher stiffness in elastography and areas without contrast media uptake in the late phase (CEUS). In addition, CEUS detected capillary microcirculation of benign and malignant liver lesions smaller than 10 mm.

CONCLUSION

Beyond human breast cancer HTM additionally developed small parenchymal liver lesions, which could be characterized by HRU in combination with CEUS and elastography in-vivo. Nevertheless, the defined diagnoses of solid liver lesions less than 5 mm require confirmation by histopathology.

First results of endocavity evaluation of the microvascularization of malignant prostate tumors using contrast enhanced ultrasound (CEUS) including perfusion analysis: first results

AIM

Detection of prostate cancer lesions using transrectal contrast enhanced ultrasound (CEUS) of the prostate utilizing quantitative perfusion analysis.

METHOD

20 patients (mean age 63 years, 47-71) with biopsy proven prostate cancer underwent transrectal ultrasound (TRUS) prior to radical prostatectomy by 2 experienced examiners using a multifrequency endocavitary probe (5-9 MHZ, LOGIQ E9, GE Healthcare, Chalfont St Giles, UK) to detect cancer-suspect lesions. CEUS was performed dynamically up to 3 Min after bolus injections of 2.4 ml SonoVue® (BRACCO, Italy). Digital cine loops were analyzed by an independent blinded examiner using perfusion quantification software with colour-coded parametric images in order to define suspect regions based on the perfusion-related parameters early wash in rate (WIR), mean transit time (MTT) and rise time (RT). The results of CEUS perfusion analysis were compared with the histopathology after surgery, obtained from whole mount sections.

RESULTS

After prostatectomy and histopathology, 34 prostate cancer foci were found in 20 patients. In 30/34 cases an early enhancement within the tumor was detected by CEUS perfusion analysis without early wash out. By evaluating the MTT and RT tumor detection was possible in 29/34 and 25/34 cases. The highest detection rate of prostate cancers was obtained by analysis of early contrast enhancement (priot to the normal prostate parenchyma), with a sensitivity of 88%, specificity 100%, NPP 60%, PPV 90%, in clinically suspicious cases with good correlation to the postoperative histopathological findings (r = 0.728).

CONCLUSION

This pilot study demonstrates, that quantitaive analysis of perfusion parameters obtained with transrectal CEUS could be helpful for characterization of neoplastic microcirculation of prostate cancer, for preoperative localization of cancer-suspect areas and for therapy guidance and management.

Percutaneous irreversible electroporation (IRE) of hepatic malignant tumours: contrast-enhanced ultrasound (CEUS) findings

PURPOSE

The aim of this study is to describe the image findings of contrast-enhanced ultrasound (CEUS) after irreversible electroporation (IRE), and to assess its usefulness in relation to the evaluation of the ablation status using a dynamic recording of the microvascularisation.

MATERIAL AND METHOD

In this prospectively designed study, a percutaneous IRE was performed for the treatment of malignant hepatic lesions in a total of 15 patients following the interdisciplinary diagnosis. The lesions were documented using CEUS before, immediately after and 20 minutes after the ablation. The acquired CEUS image data was subsequently independently retrospectively evaluated by 2 experienced radiologists and assessed in relation to microvascularisation using a 5 point scale.

RESULTS

Using CEUS, a significant reduction in the microcirculation of the lesions, both centrally and marginally, could be detected following IRE (p < 0.001 and p < 0.001). The mean evaluation of the central microcirculation was reduced from 3.13 ± 1.38 to 0.47 ± 0.64 (p < 0.01). For the peripheral area of the lesion and the ablation margin, there was a reduction of 3.37 ± 1.13 to 1.57 ± 0.46 (p = 0.001). There was no significant reduction in the macrocirculation.

CONCLUSION

Within the framework of this study, it could be demonstrated that, in the course of IRE, a rapid significant reduction of the microcirculation in the ablation area occurred.

Quantitative assessment of bone microvascularization after osteocutaneous flap transplantation using contrast-enhanced ultrasound (CEUS)

BACKGROUND

Extensive wound defects frequently have to be covered by free flap transplantation. A monitoring device for measuring capillary level perfusion of bone is currently not available.

OBJECTIVE

The aim of the study was to detect complications after osteocutaneous flap transplantation using contrast-enhanced ultrasound (CEUS). Additionally quantitative analysis was performed by special perfusion software (QONTRAST®; Bracco, Italy).

METHODS

22 patients were examined after osteocutaneous flap transplantation during the first 72 h after operation. CEUS was performed with a linear transducer (6-9 MHz, LOGIQ E9/GE) after bolus injections of 2.4 ml ultrasound contrast agent (SonoVue®; Bracco, Italy). The osseous perfusion and soft tissue perfusion were analyzed separately and quantitative perfusion analysis was performed. Five patients had to undergo reoperation due to compromised flap microvascularization.

RESULTS

In all 5 complications reduced osseous and soft tissue perfusion was seen using CEUS. Additionally using the perfusion parameters TTP (time to PEAK), RBV (regional blood volume), RBF (regional blood flow) und MTT (mean transit time), significantly lower soft tissue and osseous perfusion was detected.

CONCLUSION

CEUS seems to be capable of detecting vascular disturbances and of assessing microvascularization of the osseous component after osteocutaneous flap transplantation.

Palliative treatment of presacral recurrence of endometrial cancer using irreversible electroporation: a case report

INTRODUCTION

Irreversible electroporation (IRE) is a new minimally invasive tumor ablation technique which induces irreversible disruption of cell membrane integrity by changing the transmembrane potential resulting in cell death. Irreversible electroporation is currently undergoing clinical investigation as local tumor therapy for malignant liver and lung lesions. This is the first case report to describe the successful palliative ablation of a presacral recurrence of an endometrial cancer to achieve locoregional tumor control and pain relief.

CASE PRESENTATION

A 56-year-old Caucasian woman was referred for interventional treatment of an advanced local recurrence of endometrial cancer (11.9 × 11.6 × 14.9cm) with infiltration of the sacral bone and nerve plexus. Due to the immediate proximity to the sacral plexus, the patient could neither undergo surgical therapy nor a second radiation therapy. Due to its ablation mechanism irreversible electroporation was deemed to be the best therapy option.

CONCLUSION

We showed in this case that a large tumor mass adjacent to a bundle of neural structures, the sacral plexus, can be widely ablated by irreversible electroporation with only minor temporary impairment of the neural function, even though a large infiltrating tissue volume (941cm3) was ablated.