Signal from hepatic hemangiomas on power Doppler US: real or artefactual?

A Comprehensive Review of Hepatic Hemangioma Management

BACKGROUND

Hepatic hemangiomas (HHs) are benign liver lesions often discovered incidentally on imaging for various unrelated pathologies. We herein review the etiology, classification, diagnostic imaging, and management of HHs.

METHODS

A comprehensive systematic review was performed utilizing MEDLINE/PubMed and Web of Science databases, with the end of search date being March 1, 2022, regarding HH diagnosis, imaging, and management.

RESULTS

HHs can be broadly classified as capillary hemangiomas or cavernous hemangiomas. While the exact pathophysiology related to the development of HHs remains largely unknown, hormone exposure has been postulated to cause HH growth. HHs appear homogenously hyperechoic on US with distinct margins and posterior acoustic enhancement. While cavernous hemangiomas appear as well-defined hypodense lesions on pre-contrast CT images with the same density as the vasculature, one of the most reliable imaging features for diagnosing cavernous hemangiomas is high signal intensity on T2 weighted images. While most HHs are asymptomatic, some patients can present with pain or compressive symptoms with bleeding/rupture being very rare. Kasabach-Merritt syndrome is a rare but life-threatening condition associated with thrombocytopenia and microangiopathic hemolytic anemia. When HHs are symptomatic or in the setting of Kasabach Merritt syndrome, surgery is indicated. Enucleation is an attractive surgical option for HH as it spares normal liver tissue. Most patients experience symptom relief following surgical resection.

CONCLUSION

HHs are very common benign liver lesions. High-quality imaging is imperative to distinguish HHs from other liver lesions. Surgery is generally reserved for patients who present with symptoms such as pain, obstruction, or rarely Kasabach-Merritt syndrome. Surgery can involve either formal resection or, in most instances, simple enucleation. Patients generally have good outcomes following surgery with resolution of their symptoms.

Contrast-Enhanced Ultrasound as a Problem-Solving Modality: Tips and Tricks

ABSTRACT

Contrast-enhanced ultrasound (CEUS) continues to be an ever-growing tool in radiation-free imaging. While it has been widely used in cardiac imaging, CEUS has only recently become an Food and Drug Administration-approved and viable modality for evaluation of abdominal structures. Ultrasound contrast agents are nontoxic, microbubble-based vascular agents and can be used to reliably assess enhancement patterns of various lesions in real time. In particular, it's non nephrotoxic nature makes CEUS a particularly important tool in renal failure patients requiring serial follow-up. This review provides a comprehensive discussion on the utility of CEUS agents, imaging techniques, comparison with traditional cross-sectional imaging modalities, and its application in diagnosing kidney and liver lesions. This pictorial review is illustrated with cases of renal and hepatic lesions that the practicing radiologist should become familiar with as CEUS becomes increasingly popular.

Surgical management of giant hepatic hemangioma: A 10-year single center experience

Background

Hepatic hemangiomas are the most typical benign mesenchymal lesions of the liver. Most of these lesions are asymptomatic. Giant hepatic hemangiomas (GHH) (>10 cm) are often symptomatic and require surgical intervention. This study aimed to describe the clinical findings, risk factors, diagnostic approach and management of GHH.

Methods

We performed a retrospective analysis of patients with GHH treated at our hospital from January 2008 to December 2018. The medical records of each patient were reviewed to obtain the clinical and surgical data.

Results

Twelve patients with GHH were treated during the study period. 9 were female and 3 were male. The mean age of diagnosis was 48,2 years. The most common presenting symptom was abdominal pain. Eight patients presented an abdominal mass. Indications for surgical resections were rupture (n = 2), Kasabach-Merritt syndrome (n = 1) and abdominal pain (n = 9). Right hepatectomy was done in four patients, left lobectomy in four patients, and enucleation in four patients. Embolization was performed in 4 patients, but due to the persistence of symptoms or bleeding, surgery was indicated. The mean operative time was 3.5 h, and median blood loss was 870 ml. The median hospital stay was 5.3 days. For four patients, we registered postoperative complications causing death in one case. All alive patients were asymptomatic at a median follow-up of 55 months.

Conclusion

Despite limitations and alternative modalities, surgery remains the only effective curative treatment for GHH.

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Hepatic hemangiomas are the most common benign tumors of the liver with the incidence of 0.4–20%.

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Giant hepatic hemangiomas (GHH) are usually responsible for overt clinical symptoms and complications.

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Management of liver hemangiomas ranges from close observation to surgery depending upon the site, size and symptoms.

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Surgical resection is indicated in patients with abdominal complaints or complications, or when diagnosis remains inconclusive.

Superb microvascular imaging technology for ultrasound examinations: Initial experiences for hepatic tumors

PURPOSE

To explore whether superb microvascular imaging (SMI) technology could be helpful for the evaluation of hepatic tumors.

MATERIALS AND METHODS

Our institutional review board approved this study, and informed consent was obtained from all of the patients. Twenty-three patients with 29 hepatic tumors were enrolled in our study. The tumors consisted of hemangiomas (n=15), focal nodular hyperplasias (FNHs) (n=7), and hepatocellular carcinomas (n=7). All lesions were pathologically (n=2) or radiologically (n=27) confirmed. The mean tumor diameter was 1.9cm (range, 0.9cm to 5.0cm). Using SMI technology, all lesions were scanned and categorized into subgroups according to the flow pattern on the SMI.

RESULTS

The hemangiomas exhibited nodular rim patterns (33%) and spotty dot-like patterns (20%), and both of these findings were very specific for the diagnosis of hemangioma. The FNHs exhibited spoke-wheel patterns (43%) and radiating vessel patterns (29%) that were very specific findings for the diagnosis of FNH. The other tumors did not exhibit any specific patterns on SMI.

CONCLUSION

Evaluations of the inner vascularities of hepatic tumors with the SMI technique were feasible, and the SMI features were significantly different between the different types of hepatic tumors. These differences could aid the diagnoses of hepatic tumors with US.

The interobserver reliability of three-dimensional power Doppler data acquisition within the female pelvis

OBJECTIVES

To examine the interobserver reliability of three-dimensional (3D) power Doppler data acquisition from the uterus and ovary.

METHODS

3D power Doppler angiography was used to acquire endometrial data from 20 patients and ovarian data from a further 20 different patients at various stages of in vitro fertilization. Two different observers each acquired two datasets from all 40 patients resulting in 80 endometrial and 80 ovarian datasets in total. Virtual Organ Computer-aided AnaLysis was used to define the object of interest and semiquantify the power Doppler signal within it. The reliability of measurements of volume and vascularity was assessed by calculating interclass correlation coefficients (ICCs) and limits of agreement between the two observers.

RESULTS

Whilst volumetric data proved more reliably acquirable than power Doppler data, the interobserver reliability of data acquisition was high overall for both the endometrium and ovary with all measurements obtaining a lower ICC of above 0.9. Limits of agreement revealed minimal disagreement between the two observers for measurements of volume and vascularity within both the ovary and endometrium. The 'indices of vascularity' within the endometrium were less than those derived from the ovary and subendometrium, which were comparable.

CONCLUSIONS

3D ultrasound can be reliably used between observers to acquire power Doppler information from the ovary and endometrium thus supporting the current use and further development of this technique in clinical practice.

Evaluation of hepatic focal nodular hyperplasia with contrast-enhanced gray scale harmonic sonography: initial experience

OBJECTIVE

To assess the potential of contrast-enhanced gray scale harmonic sonography in the evaluation of the typical vascular and enhancement patterns of hepatic focal nodular hyperplasia.

METHODS

Thirteen patients with 13 lesions of hepatic focal nodular hyperplasia underwent contrast-enhanced gray scale harmonic sonography. After the injection of a microbubble contrast agent (SH U 508A), gray scale harmonic sonographic studies using a Coded Harmonic Angio technique were performed with a combination of a period of continuous scanning to assess the vascular pattern (vascular imaging) and interval delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed by consensus of 2 experienced radiologists.

RESULTS

In 12 (92%) of 13 lesions, vascular imaging during the arterial phase showed central arteries of a spoked wheel pattern, whereas the remaining lesion had stippled vascularity. On acoustic emission imaging, 11 (85%) of 13 lesions were hyperechoic during the early phase, and the remaining 2 (15%) were isoechoic compared with surrounding parenchyma. Ten (77%) of 13 lesions remained either hyperechoic (5 of 13) or isoechoic (5 of 13) during the delay phase, whereas the remaining 3 lesions (23%) were hypoechoic.

CONCLUSIONS

Contrast-enhanced gray scale harmonic sonography showed the typical vascularity of a spoked wheel pattern during the vascular phase and persistent enhancement on serial acoustic emission imaging in most cases of hepatic focal nodular hyperplasia, and thereby it can be a promising technique in noninvasive diagnosis of this entity.

Twinkling artifact on color Doppler sonography: dependence on machine parameters and underlying cause

OBJECTIVE

The objective of our study was to evaluate the color Doppler sonographic effect known as twinkling artifact.

MATERIALS AND METHODS

Struvite (ammonium magnesium phosphate) stone fragments, wire mesh, and a flat surface were scanned in a water bath with a sonography scanner using a high-frequency linear array probe fixed in a ring clamp. Pulse repetition frequency, color-write priority, gray-scale gain, and spectral Doppler gain were varied. Color and spectral Doppler modes were used.

RESULTS

Twinkling artifact and spectral broadening were seen most intensely behind struvite stone fragments, and both were seen more strongly behind wire mesh with greater surface roughness than behind wire mesh with less surface roughness or a flat surface. The appearance of the twinkling artifact is highly dependent on machine settings. System noise measured on a flat surface generates a band-limited Doppler shift on spectral displays with a mean frequency shift of 0 Hz and a mean (+/- SD) absolute fluctuation of 86 +/- 10 Hz over a pulse repetition frequency range of 1250-10,000 Hz. Rough surfaces increase the spectral bandwidth.

CONCLUSION

The appearance of the twinkling artifact is highly dependent on machine settings and is likely generated by a narrow-band, intrinsic machine noise called phase (or clock) jitter. Surface roughness secondarily broadens the noise spectrum. With a strongly reflecting, rough surface such as a renal stone, the high amplitude, broadband signal appears as random motion in color Doppler sonography. Understanding of the twinkling artifact may result in better use of its clinical appearance.

Focal hepatic lesions: evaluation with contrast-enhanced gray-scale harmonic US

OBJECTIVE

To determine the findings of various focal hepatic lesions at contrast-enhanced gray-scale ultrasound (US) using a coded harmonic angio (CHA) technique and emphasizing lesion characterization.

MATERIALS AND METHODS

The study involved 95 patients with 105 focal hepatic lesions, namely 51 hepatocellular carcinomas (HCCs), 22 metastases, 22 hemangiomas, four cases of focal nodular hyperplasia (FNH), and six nontumorous nodules. After the injection of a microbubble contrast agent (SH U 508A), gray-scale harmonic US studies using a CHA technique were performed with a combination of continuous scanning to assess the intratumoral vasculature (vascular imaging) and interval-delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed.

RESULTS

At vascular imaging, 69% of HCCs (35/51) showed irregular branching vessels, while in 91% of metastases (20/22) a peripherally stippled pattern was observed. Intratumoral vessels were absent in 95% of hemangiomas (21/22) and all nontumorous lesions (6/6), while in 75% of FNHs (3/4) a spoke-wheel pattern was evident. At acoustic emission imaging, 71% of HCCs (36/51) showed heterogeneous enhancement and 86% (19/22) of metastases showed rim- or flame-like peripheral enhancement during the early phase, with washout occurring in all HCCs and metastases (100%, 73/73) during the late phase. In hemangiomas, enhancement was either peripheral and nodular (19/22, 86%) or persistent and homogeneous (3/22, 14%), and 75% of FNHs (3/4) became isoechoic during the late phase.

CONCLUSION

At contrast-enhanced gray-scale US using a CHA technique, a period of continuous scanning depicted the intratumoral vasculature, and interval-delay scanning demonstrated the sequential enhancement pattern. The characteristic findings of various focal hepatic lesions were thus determined.

Pulse inversion sonography in the early phase of the sonographic contrast agent Levovist: differentiation between benign and malignant focal liver lesions

OBJECTIVE

To determine whether examination of focal liver lesions by pulse inversion sonography in the early perfusion phase of the contrast agent Levovist (SH U 508A; Schering AG, Berlin, Germany) enables distinction between benign and malignant lesions.

METHODS

Seventy-two patients were examined. The cause of the lesion was confirmed by liver biopsy, computed tomography, or both or by hepatic iminodiacetic acid-enhanced scintigraphy. Forty-two patients had malignant liver lesions, and 30 had benign liver lesions. After injection of 2 g of Levovist intravenously, analysis of Levovist arrival was performed by the interval delay imaging technique for 60 seconds.

RESULTS

The early arrival of Levovist less than 30 seconds after injection was used as an indicator for malignancy and had specificity of 67% and sensitivity of 60% (P < .05). The central starlike fill-in as a sign for focal nodular hyperplasia had specificity of 100% and sensitivity of 67% (P < .001). The rimlike pattern followed by centripetal fill-in as a sign for hemangioma had specificity of 100% and sensitivity of 18% (P < .01). In contrast, the early diffuse stippled arrival pattern was found in 60% of malignant lesions and also in 33% of cases of focal nodular hyperplasia and in 1 patient with an adenoma.

CONCLUSIONS

Analysis of Levovist arrival time cannot distinguish between a malignant or benign lesion in individual cases. However, the central starlike arrival pattern is characteristic of focal nodular hyperplasia.

A straightforward algorithm for the quantification of power Doppler signals

RATIONALE AND OBJECTIVES

To document a simple algorithm that quantifies power Doppler signals by computer-based statistical image analysis.

METHODS

Personal computer-based software was developed. Color pixels representing power Doppler signals were separated from the background gray pixels in power Doppler images converted in BMP format. To avoid misregistration during this segmentation, a threshold value is required to adequately distinguish between gray and color pixels. Equating the intensity of each color pixel to a Power Value (PV), a histogram of Power Values in power Doppler images was obtained.

RESULTS

The software was designed to allow users to adjust two thresholds (Difference Threshold and Intensity Threshold) by observing the segmentation results in real time. The software calculates the following indexes within any region of interest as defined by the operator: mean PV, peak PV, standard deviation of PV, percentage power Doppler area, and integrated PV per unit area.

CONCLUSIONS

Power Doppler signals can be objectively quantified using this straightforward algorithm. This simple and practical method can be applied to comparative or longitudinal studies upon vascularity or blood flow.

Hepatic hemangiomas: spectrum of US appearances on gray-scale, power Doppler, and contrast-enhanced US

Because US plays a key role in the initial evaluation of hepatic hemangiomas, knowledge of the entire spectrum of US appearances of these tumors is important. Most hemangiomas have a distinctive US appearance, and even with those with atypical appearances on conventional gray-scale US, specific diagnoses can be made using pulse-inversion harmonic US with contrast agents. In this essay, we review the spectrum of US appearances of hepatic hemangiomas on conventional gray-scale, power Doppler, and pulse-inversion harmonic US with contrast agents.