Contrast-Enhanced Ultrasound (CEUS) in Pregnancy: A Comprehensive Review of Clinical Applications

Abstract

Background

Imaging during pregnancy presents unique challenges. Computed tomography (CT) is generally avoided due to fetal radiation exposure, and magnetic resonance imaging (MRI) may be limited by concerns regarding gadolinium-based contrast agents. As a result, ultrasound (US) remains the primary imaging tool during pregnancy. Contrast-enhanced ultrasound (CEUS) expands the diagnostic capabilities of conventional US by providing real-time vascular information comparable to contrast-enhanced CT or MRI. Importantly, microbubble contrast agents used in CEUS do not cross the placenta and have shown no fetal harm in clinical studies. Nevertheless, CEUS remains an off-label technique during pregnancy, underscoring the need for a comprehensive review of the available literature to assess its safety and clinical applications during pregnancy.

Method

This review summarizes the current evidence up to 2025 on the use of CEUS in pregnancy and highlights its clinical value with respect to evaluating acute and chronic maternal conditions – including oncologic, vascular, infectious, inflammatory, and other organ-specific pathologies – illustrated through representative case examples. Clinical studies, case reports, and international guidelines were analyzed with a focus on safety and diagnostic performance.

Conclusion

Although still off-label, CEUS demonstrates an excellent safety profile and high diagnostic utility when clinically indicated in pregnancy. No maternal, fetal, or neonatal adverse effects have been reported, and no placental transfer of microbubbles has been demonstrated. CEUS enables high-resolution assessment of abdominal organs, vascular pathologies, and inflammatory or infectious changes, reducing the need for ionizing or gadolinium-based imaging. It represents a safe, effective, and radiation-free diagnostic alternative when conventional imaging is limited.

Key Points

• CEUS expands diagnostic ultrasound without radiation exposure.

• CEUS is a safe alternative to CT or MRI.

• Microbubbles remain intravascular and do not cross the placenta.

• No maternal, fetal, or neonatal adverse effects reported.

• Case examples illustrate safety and diagnostic value.

Citation Format

• Begaj K, Sperr AG, Clevert DA. Contrast-Enhanced Ultrasound (CEUS) in Pregnancy: A Comprehensive Review of Clinical Applications. Rofo 2026; DOI 10.1055/a-2784-9759

Zusammenfassung

Hintergrund

Die Bildgebung während der Schwangerschaft stellt besondere Herausforderungen dar. Die Computertomografie (CT) wird aufgrund der Strahlenbelastung des Föten in der Regel vermieden, und die Magnetresonanztomografie (MRT) kann durch Bedenken hinsichtlich gadoliniumhaltiger Kontrastmittel eingeschränkt werden. Daher bleibt der Ultraschall (US) das wichtigste bildgebende Verfahren während der Schwangerschaft. Der kontrastverstärkte Ultraschall (CEUS) erweitert die diagnostischen Möglichkeiten des konventionellen US, indem er in Echtzeit Gefäß-/Vaskularisierungsinformationen liefert, die mit denen der kontrastverstärkten CT oder MRT vergleichbar sind. Wichtig ist, dass die bei CEUS verwendeten Mikrobläschen-Kontrastmittel die Plazenta nicht passieren und in klinischen Studien keine fetalen Schäden gezeigt haben. Dennoch bleibt CEUS in der Schwangerschaft eine Off-label-Technik, was die Notwendigkeit einer umfassenden Übersicht über die verfügbare Literatur zur Bewertung von Sicherheit und klinischen Anwendungen unterstreicht.

Methode

Diese Übersichtsarbeit fasst die aktuelle Evidenz bis 2025 zum Einsatz von CEUS in der Schwangerschaft zusammen und hebt den klinischen Nutzen bei der Beurteilung akuter und chronischer maternaler Erkrankungen hervor – einschließlich onkologischer, vaskulärer, infektiöser, entzündlicher und anderer organspezifischer Pathologien – veranschaulicht durch repräsentative Fallbeispiele. Klinische Studien, Fallberichte und internationale Leitlinien wurden hinsichtlich Sicherheit und diagnostischer Aussagekraft ausgewertet.

Schlussfolgerung

Obwohl derzeit Off-label, zeigt CEUS bei entsprechender Indikation in der Schwangerschaft ein exzellentes Sicherheitsprofil und eine hohe diagnostische Aussagekraft. Weder maternale, fetale noch neonatale Nebenwirkungen wurden berichtet, und ein plazentarer Übertritt der Mikrobläschen wurde nicht beobachtet. CEUS ermöglicht eine hochauflösende Beurteilung abdomineller Organe, vaskulärer Pathologien und entzündlicher oder infektiöser Veränderungen und reduziert den Bedarf an strahlen- oder gadoliniumhaltiger Bildgebung. Es stellt somit eine sichere, effektive und strahlungsfreie Alternative dar, wenn konventionelle Verfahren limitiert sind.

Kernaussagen

• CEUS erweitert die Ultraschalldiagnostik ohne Strahlenexposition.

• CEUS ist eine sichere Alternative bei Kontraindikationen für CT oder MRT.

• Mikrobläschen bleiben intravaskulär und passieren die Plazenta nicht.

• Keine maternalen, fetalen oder neonatalen Nebenwirkungen berichtet.

• Fallbeispiele veranschaulichen Sicherheit und diagnostischen Nutzen.

Keywords

pregnancy - safety - microbubbles - contrast-enhanced ultrasound (CEUS)

Introduction

Ultrasound is the first-line imaging modality in obstetrics due to its broad availability and excellent safety profile. In contrast, computed tomography (CT), positron emission tomography (PET), and X-ray imaging should only be used when the diagnostic benefit clearly outweighs the fetal risk, i.e., in life-threatening emergencies. Their use in pregnancy is limited due to the potential teratogenic and carcinogenic effects of ionizing radiation on the fetus [1] [2].

Magnetic resonance imaging (MRI), although free of radiation, also has limitations – particularly due to concerns about maternal hemodynamic effects in late pregnancy, such as vena cava compression in the supine position and the uncertain safety of gadolinium-based contrast agents, which cross the placental barrier [3]. Additionally, biological effects from static magnetic fields, radiofrequency energy deposition, and acoustic noise may pose a potential risk to the fetus, particularly during the first trimester. Animal studies have shown detectable effects, although no adverse outcomes have been reported in humans to date [4] [5].

Contrast-enhanced ultrasound (CEUS) provides real-time vascular imaging with diagnostic performance comparable to CT or MRI, without the risks of ionizing radiation [6]. Its microbubble agents, consist of gas microbubbles encased in a protein, lipid, or polymer shell [7]. These metabolically inert microbubbles remain confined to the intravascular space, are cleared through the lungs, and do not cross the placenta, making CEUS a safe alternative during pregnancy [8].

Modern CEUS in pregnancy should be performed with contrast-specific, low–mechanical index (MI < 0.1) imaging to minimize microbubble destruction while maximizing sensitivity to nonlinear microbubble signals. Second-generation agents, such as sulfur hexafluoride microbubbles, are typically administered as a small intravenous bolus (≈1–2.4 mL), followed by a saline flush, with continuous cine recording from the early arterial phase (about 5–15 s after injection) through the portal-venous and late phases up to 5–6 minutes [7] [9] [10]. Modern systems employ pulse-inversion and amplitude-modulation techniques to suppress tissue signals and enhance the nonlinear microbubble response. High-frame-rate CEUS (HiFR-CEUS) further improves temporal resolution and visualization of rapid arterial and microvascular patterns [9]. However, no large prospective studies have evaluated the safety, dosing, or diagnostic benefit of HiFR-CEUS in pregnancy. Appropriate adjustment of gain, dynamic range, and a single shallow focal zone further ensures robust and reproducible contrast imaging.

We have reviewed the current literature and guidelines dealing with the principal ultrasound contrast agents employed in clinical practice, explaining the risks of administration for the mother and the fetus, the adverse effects associated, and the main clinical recommendations for their use.

Safety of Contrast-Enhanced Ultrasound During Pregnancy

The safety profile of contrast-enhanced ultrasound (CEUS) using microbubbles during pregnancy has been a subject of growing interest, particularly due to its potential for detailed vascular imaging without ionizing radiation. Although CEUS remains an off-label application and is not currently approved by leading obstetric and ultrasound societies, both clinical experience and preclinical data suggest a reassuring safety profile [8] [11].

A recent review by Dassen et al. (2024) analyzing 13 studies with 256 pregnant women reported no clinically significant maternal, fetal, or neonatal adverse events [12], a finding echoed by other clinical studies [10] [13] [14] [15]. Other studies show that no fetal contrast enhancement was observed in any case, indicating that microbubbles do not cross the placental barrier [16] [17]. These findings further support the potential safety of CEUS when clinically indicated during pregnancy.

In the non-pregnant population, where studies involve a much larger number of participants, adverse reactions to CEUS are only very rare but can include mild symptoms such as rash, nausea, and back pain, or more severe reactions like early anaphylactic shock. However, these reactions are transient, and no fatalities have been reported [11] [18].

Although CEUS remains an off-label technique in pregnancy, selected high-risk clinical scenarios may warrant its use when standard ultrasound modalities fail to provide sufficient diagnostic clarity. Emerging evidence suggests that CEUS can meaningfully influence maternal management – for example, by refining the assessment of placental perfusion abnormalities, delineating benign from suspicious uterine or abdominal lesions, or clarifying the vascularity of complex adnexal or uterine findings – thereby reducing the need for CT or gadolinium-enhanced MRI [16] [19]. Such applications highlight the potential diagnostic benefit in circumstances where timely and accurate characterization directly affects clinical decision-making.

From an ethical and regulatory standpoint, the use of CEUS in pregnancy requires rigorous justification. To date, there is no official approval for the use of CEUS during pregnancy from major professional societies, including the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), the World Federation for Ultrasound in Medicine and Biology (WFUMB), or the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG). Therefore, CEUS is not currently recommended for obstetric imaging due to limited prospective data and the lack of formal regulatory approval [12] [19] [20]. Consequently, any maternal CEUS examination should be considered on a case-by-case ethical basis, with a careful risk–benefit assessment and informed consent regarding its off-label use.

Given the off-label nature of CEUS in pregnancy and the need for meticulous safety assessment, examinations should be performed exclusively by clinicians with advanced expertise in diagnostic ultrasound [10] [11]. The EFSUMB Clinical Safety Statement emphasizes that the use of ultrasound contrast agents remains off-label in pregnancy and that ultrasound exposure in this context should strictly follow the ALARA principle with careful monitoring of mechanical and thermal indices [21]. Similarly, the EFSUMB guidelines on non-hepatic CEUS note that most CEUS applications are off-label and should therefore be performed only by adequately trained operators and within the medico-legal framework of each individual country [11]. Ideally, CEUS in pregnant patients should be conducted by specialists certified in prenatal diagnostics or abdominal ultrasound who are fully trained in contrast-specific imaging modes, microbubble kinetics, and maternal–fetal risk assessment. Operators should have documented experience performing CEUS in the non-pregnant adult population and should be competent in the emergency management of rare contrast-related reactions [8]. Interdisciplinary collaboration with maternal–fetal medicine specialists is recommended for appropriate indication setting, procedural monitoring, and post-procedural management.

CEUS in Oncologic Imaging During Pregnancy

The maternal organs most frequently evaluated with CEUS during pregnancy are those in which detailed vascular characterization provides essential diagnostic information when conventional ultrasound is inconclusive [2] [6] [13]. These include the liver, for the characterization of focal lesions; the kidneys, for the differentiation of inflammatory, vascular, and neoplastic entities; the gallbladder, for the assessment of polyps and wall lesions; and the abdominal vasculature, including the portal vein, hepatic veins, inferior vena cava, aorta, and mesenteric and renal arteries and veins.

The Role of CEUS in Evaluating Renal Masses in Pregnancy

The increasing incidental detection of renal masses underscores the need for improved pre-surgical assessments, as the majority of these lesions are ultimately diagnosed as benign, with angiomyolipomas (AMLs) being the most common finding upon histopathological examination [22] [23]. Distinguishing between renal cell carcinoma (RCC) and renal angiomyolipomas (AMLs) remains a critical clinical challenge due to the potential for malignant progression and the associated risks for both the mother and fetus. Contrast-enhanced ultrasound (CEUS) in the non-pregnant population, incorporating both qualitative and quantitative parameters, has shown promise in this context [23]. RCCs typically exhibit heterogeneous enhancement, rapid washout, and a pseudocapsule sign [24] [25] [26], whereas AMLs are characterized by slow centripetal enhancement, homogeneous peak enhancement, and gradual washout [27].

Although the incidence of renal masses in pregnancy is comparable to that in the general population, data on CEUS use in pregnant patients remain limited. One published case describes a 30-year-old woman at 27 weeks of gestation with a left renal mass detected on routine prenatal ultrasound. B-mode imaging revealed a hypoechoic lesion, and color Doppler showed no hypervascularization. CEUS demonstrated enhancement with slight washout, features suggestive of AML. Although unenhanced MRI could not rule out malignancy, biopsy confirmed a lipid-poor AML. Serial CEUS exams at 28, 29, 30, and 31 weeks showed no progression, supporting conservative management. The patient delivered a healthy neonate at 38 weeks [25]. This case illustrates the potential of CEUS as a safe and effective imaging modality for characterizing and monitoring renal masses during pregnancy.

Furthermore preliminary data from non-pregnant populations suggest that CEUS performs comparably to, or even better than, contrast-enhanced computed tomography (CECT) and contrast-enhanced magnetic resonance imaging (CEMR) – currently considered the gold standards for renal mass characterization [28]. These findings highlight the need for further research on the application of CEUS in pregnant patients, where safer imaging alternatives are critically important.

The Role of CEUS in Characterizing Liver Lesions in Pregnancy

Contrast-enhanced ultrasound (CEUS) enables real-time assessment of lesion vascularity, with a sensitivity >95% and specificity ~83% for differentiating benign from malignant lesions in the non-pregnant population [29]. It allows continuous cine assessment of microbubble perfusion through the arterial (10–20 s), portal-venous (30–45 s), and late (~120 s) vascular phases, relative to the liver parenchyma [30]. Benign focal liver lesions are often incidentally detected on unenhanced ultrasound but typically remain indeterminate without further imaging [30].

With the help of CEUS in a single-center series of six pregnant women (gestational age range: 12–35 weeks), CEUS enabled definitive characterization in every case, eliminating the need for biopsy or ionizing imaging. Simple cysts (n = 1; 24 weeks of gestation) remained entirely anechoic throughout all three phases, confirming benignity. Cavernous hemangiomas (n = 2; 19 and 33 weeks) exhibited the archetypal peripheral, nodular arterial enhancement with progressive centripetal fill-in, reaching near-complete isoenhancement by 60–120 s, mirroring non-pregnant perfusion patterns. Focal nodular hyperplasia (n = 1; 15 weeks) demonstrated the “spoke-wheel” arterial filling pattern from a central scar and homogeneous isoenhancement in the portal-venous and late phases, thereby obviating invasive diagnostic procedures [13] [14] [15]. As an illustrative case, an indeterminate hepatic lesion incidentally detected during pregnancy was subsequently assessed using a multimodal ultrasound approach. B-mode sonography demonstrated an isoechoic lesion ([Fig. 1]) with increased central vascularity on color Doppler imaging ([Fig. 2]) and slow intralesional flow on MicroFlow Imaging ([Fig. 3]). Contrast-enhanced ultrasound (CEUS) revealed a characteristic enhancement pattern with pronounced central-to-peripheral hyperenhancement during the arterial phase ([Fig. 4]), followed by homogeneous iso- to hyperenhancement in the portal-venous phase ([Fig. 5]) and sustained iso- to hyperenhancement without washout in the late phase ([Fig. 6]). This enhancement profile was consistent with focal nodular hyperplasia (FNH), allowing a confident benign diagnosis without the need for additional imaging.

Fig. 1 A 39-year-old woman in her twenty-ninth week of pregnancy presented with diminished fetal movements since the morning. No contractions, no bleeding, no loss of amniotic fluid were reported. The pregnancy had been unremarkable so far. Emergency ultrasound revealed an unclear nearly isoechoic liver lesion (yellow arrows).

Fig. 2 Same patient as in Fig. 1. The lesion (yellow arrows) has increased central vascularity (white arrow). The diameter of the lesion is approximately 4 cm.

Fig. 3 Same patient as in Figs. 1 and 2. The MicroFlow Imaging (white arrow) detects slow and weak blood flow in the liver lesion tissue (yellow arrows).

Fig. 4 Same patient as in Figs. 1–3. Dual-mode imaging displaying contrast-enhanced ultrasound (CEUS) on the left (a) and corresponding B-mode scan on the right (b). In the arterial phase, the lesion (white arrows) is delineated by strong hyperenhancement from the center to the periphery on the contrast image.

Fig. 5 Same patient as in Figs. 1–4. Dual-mode imaging displaying contrast-enhanced ultrasound (CEUS) on the left (a) and corresponding B-mode scan on the right (b). In the portal-venous phase, the lesion is delineated by complete hyper- to isoenhancement (white arrows) on the contrast image.

Fig. 6 Same patient as in Figs. 1–5. Dual-mode imaging displaying contrast-enhanced ultrasound (CEUS) on the left (a) and corresponding B-mode scan on the right (b). In the late phase, the lesion is delineated by complete iso- to hyperenhancement (white arrows) on the contrast image. No washout could be detected. The final diagnosis was a FNH.

Malignant liver metastases (n = 1; 24 weeks) from rectal carcinoma exhibited irregular, heterogeneous arterial hyperenhancement, central nonperfusion, and rapid washout beginning in the late arterial phase, prompting immediate oncologic referral and rendering CT/MRI unnecessary [13] [14] [15].

These examples underscore that, even in advanced gestation, CEUS provides high-fidelity vascular signatures – cystic nonenhancement, hemangioma centripetal fill-in, FNH spoke-wheel perfusion, abscess rim enhancement, and metastatic washout – that reliably distinguish benign from malignant or infectious liver lesions, thereby minimizing maternal and fetal exposure to invasive or ionizing diagnostics.

The Role of CEUS in Characterizing Gallbladder Lesions in Pregnancy

Contrast-enhanced ultrasound (CEUS) provides critical vascular insights into gallbladder lesions during pregnancy, distinguishing a benign pathology from a malignant one. Gallbladder polyps, which often appear as small, non-shadowing hyperechoic elevations on B-mode, consistently demonstrate homogeneous enhancement in the late vascular phase without early arterial hypervascularization. In a 33-year-old woman at 17 weeks of gestation, CEUS confirmed uniform late-phase enhancement of a 6 mm polyp, effectively excluding neoplastic adenoma or carcinoma and permitting continued expectant management without further imaging [10].

In contrast, gallbladder carcinoma – though rare in pregnancy – would be expected to show early irregular arterial enhancement and rapid washout during the portal-venous or late phases, reflecting malignant neoangiogenesis [31]. This pattern was notably absent in all reported benign cases, underscoring CEUS’s high negative predictive value. By enabling real-time assessment of microvascular architecture, CEUS has rendered additional MRI or invasive diagnostics largely unnecessary, thereby streamlining care and optimizing maternal-fetal safety.

As an additional illustrative example, an incidental gallbladder lesion identified during the same examination presented as a small hyperechoic, non-shadowing elevation on B-mode ultrasound ([Fig. 7]). Color Doppler imaging revealed no detectable vascularization ([Fig. 8]), while MicroFlow Imaging demonstrated slow intralesional flow ([Fig. 9]). On CEUS, the lesion showed moderate, homogeneous arterial-phase enhancement without early hypervascularization or rapid washout ([Fig. 10]). These imaging characteristics were consistent with a benign gallbladder polyp and obviated the need for further diagnostic evaluation.

Fig. 7 Same patient as in Figs. 1–6. An incidental hyperechoic gallbladder lesion (yellow arrow) without dorsal shadowing was detected.

Fig. 8 Same patient as in Figs. 1–7. The lesion (yellow arrow) shows no vascularization on color Doppler ultrasound. The diameter of the lesion is approximately 5 mm.

Fig. 9 Same patient as in Figs. 1–8. MicroFlow Imaging detects slow flow (white arrow) within the gallbladder lesion.

Fig. 10 Same patient as in Figs. 1–5. Dual-mode imaging displaying contrast-enhanced ultrasound (CEUS) on the left (a) and corresponding B-mode scan on the right (b). In the arterial phase, the lesion (white arrows) is delineated by moderate enhancement on the contrast image. The final diagnosis was a gallbladder polyp.

CEUS in the Evaluation of Vasculature Pathologies During Pregnancy

Pregnancy-related thrombosis is a major cause of maternal mortality. Pregnancy and the puerperium are associated with a fourfold to fivefold increased risk of thrombosis when compared with the nonpregnant state. This heightened risk stems from physiological adaptations that, while crucial for reducing peripartum bleeding, predispose patients to thromboembolic events [32] [33].

Contrast-enhanced ultrasound (CEUS) offers significant potential for the assessment of thrombosis during pregnancy – particularly abdominal thrombosis. However, its use in this setting is still underreported in the literature. In one case, a 34-year-old pregnant woman with a complex vascular history, including previous superior mesenteric vein (SMV) thrombosis and extensive gastrointestinal surgery, underwent serial CEUS examinations at 17, 22, and 24 weeks of gestation. Imaging showed persistent residual SMV thrombosis with only marginal microbubble distribution, confirming the stability of the thrombus. No internal Doppler signal was detected in the SMV, and findings were consistent with a subsequent MRI examination performed at 22 weeks. CEUS enabled monitoring of this high-risk vascular condition during pregnancy, supporting continued anticoagulation management without exposing the patient or fetus to additional risks [10].

Beyond SMV assessment, CEUS has proven effective in the non-pregnant population for evaluating thrombi in other abdominal veins, including the hepatic and inferior vena cava, as well as for confirming portal vein thrombosis (PVT), often reducing the need for further imaging [34]. Importantly, CEUS can distinguish malignant from bland PVT by identifying arterial-phase enhancement within the thrombus – a hallmark of neovascularization – well before contrast fills the portal lumen, thus surpassing Doppler with regard to diagnostic accuracy [35] [36] [37] [38]. CEUS also facilitates the evaluation of vascular pathologies involving the aorta, renal, and mesenteric arteries [34]. Its established utility in non-pregnant populations underscores its promising role in safely managing vasculature pathologies during pregnancy.

CEUS for Imaging of Infectious and Inflammatory Conditions During Pregnancy

Infectious and inflammatory conditions during pregnancy present clinical challenges that are compounded by limited data on the pharmacokinetics and efficacy of anti-infectives and by concerns about maternal and fetal safety, thus highlighting the need for accurate diagnosis [39]. CEUS has proven to be a valuable tool for the detection of infectious and inflammatory conditions in pregnancy, as illustrated in the examples below.

Pyelonephritis is a significant clinical concern during pregnancy, with a prevalence ranging from 1% to 4% [40]. CEUS can detect inflammatory renal involvement, appearing as hypovascular round or wedge-shaped parenchymal areas during the late parenchymal phase. It is also effective in identifying renal abscesses, seen as non-enhancing regions that may have rim or septal enhancement. Furthermore, CEUS can be used for the monitoring of abscess resolution over time [11] [41]. A clinical case exemplifies this use in pregnancy: a 37-year-old woman at 21 weeks of gestation presented with flank pain, fever, and elevated inflammatory markers. B-mode and Doppler ultrasound were unremarkable, but CEUS showed homogeneous renal enhancement with no abscess, later confirmed by unenhanced MRI. A diagnosis of acute pyelonephritis was made, and the patient recovered fully with antibiotics [10]. Another study illustrates a case in which CEUS effectively detected post-inflammatory changes in the renal cortex of a pregnant patient [15], enabling long-term monitoring following pyelonephritis.

Another instructive example demonstrated the use of CEUS to identify hepatic infectious lesions during pregnancy. Ultrasound depicted a hypoechoic lesion ([Fig. 11]) without internal vascularization on color Doppler ([Fig. 12]). In the arterial phase, CEUS showed pronounced peripheral rim enhancement with absent central uptake ([Fig. 13]), followed by decreased perilesional perfusion in the portal-venous phase consistent with reactive inflammatory changes ([Fig. 14]), and persistent hypoenhancement in the late phase. This enhancement pattern, demonstrating a non-perfused necrotic core with an enhancing inflammatory rim, was diagnostic for a hepatic abscess and allowed precise, radiation-free diagnosis and management during pregnancy.

Fig. 11 A 29-year-old woman at 8 weeks of pregnancy presented with upper abdominal pain. Unenhanced magnetic resonance imaging (MRI) revealed a focal liver lesion, but a definitive diagnosis was not possible. Differential diagnoses included a necrotic tumor, pyogenic abscess, or hydatid cyst. B-mode ultrasound demonstrated a hypoechoic liver lesion (yellow arrows).

Fig. 12 Same patient as in Fig. 11. Color Doppler ultrasound shows no vascularization within the hepatic lesion (yellow arrow). The lesion measures approximately 3 cm in diameter.

Fig. 13 Same patient as in Figs. 11 and 12. Dual-mode imaging displaying contrast-enhanced ultrasound (CEUS) on the left (a) and corresponding B-mode scan on the right (b). In the arterial phase, the hepatic lesion (yellow arrows) is delineated by strong rim enhancement and no uptake in the center.

Fig. 14 Same patient as in Figs. 11–14. Dual-mode imaging displaying contrast-enhanced ultrasound (CEUS) on the left (a) and corresponding B-mode scan on the right (b). In the late phase, the lesion is delineated by significantly decreased perfusion around the periphery (yellow arrows) on the contrast image.

Thus, beyond renal infections, CEUS has proven valuable for the evaluation of hepatic infections during pregnancy. In a reported case of amebic hepatic abscess, CEUS allowed safe diagnosis by demonstrating a necrotic, non-enhancing core with a well-defined perilesional rim that enhanced during the arterial phase and partially washed out in later phases. This allowed image-guided percutaneous drainage, while avoiding the fetal radiation exposure associated with CT [15]. Similarly, a case of cystic echinococcosis in pregnancy was accurately diagnosed using CEUS, further underscoring its potential for safely evaluating both acute and chronic infections during gestation [14].

Conclusion

CEUS represents a promising, radiation-free alternative to CT and MRI during pregnancy. It allows the accurate, real-time assessment of maternal pathologies without exposing the fetus to ionizing radiation or placental-crossing contrast agents. Existing clinical and preclinical data support its safe and effective use in selected indications throughout pregnancy.

Conflict of Interest

Der Autor Professor Dr. Dr. Clevert gibt an, Honorare für Vortrags- und Referententätigkeiten von den Firmen Samsung, Philips, Mindray, Sonoscape, Siemens und Bracco erhalten zu haben.

• References

• 1 Chen MM, Coakley FV, Kaimal A. et al. Guidelines for Computed Tomography and Magnetic Resonance Imaging Use During Pregnancy and Lactation. Obstetrics & Gynecology 2008; 112: 333-340
• 2 Committee Opinion No. 723. Guidelines for Diagnostic Imaging During Pregnancy and Lactation. Obstetrics & Gynecology 2017; 130: e210-e216
• 3 Kanal E, Barkovich AJ. Expert Panel on MR Safety. et al. ACR guidance document on MR safe practices: 2013. Magnetic Resonance Imaging 2013; 37: 501-530
• 4 Bulas D, Egloff A. Benefits and risks of MRI in pregnancy. Seminars in Perinatology 2013; 37: 301-304
• 5 Little JT, Bookwalter CA. Magnetic Resonance Safety. Magnetic Resonance Imaging Clinics of North America 2020; 28: 509-516
• 6 Nguyen SA, Burrowes DP, Merrill C. et al. Contrast-enhanced ultrasound in pregnancy. Abdom Radiol 2025;
• 7 Golemati S, Cokkinos DD. Recent advances in vascular ultrasound imaging technology and their clinical implications. Ultrasonics 2022; 119: 106599
• 8 Perelli F, Turrini I, Giorgi MG. et al. Contrast Agents during Pregnancy: Pros and Cons When Really Needed. IJERPH 2022; 19: 16699
• 9 Jung EM, Moran VO, Engel M. et al. Modified contrast-enhanced ultrasonography with the new high-resolution examination technique of high frame rate contrast-enhanced ultrasound (HiFR-CEUS) for characterization of liver lesions: First results. CH 2023; 83: 31-46
• 10 Geyer T, Rübenthaler J, Froelich MF. et al. Contrast-Enhanced Ultrasound for Assessing Abdominal Conditions in Pregnancy. Medicina 2020; 56: 675
• 11 Sidhu P, Cantisani V, Dietrich C. et al. The EFSUMB Guidelines and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound (CEUS) in Non-Hepatic Applications: Update 2017 (Long Version). Ultraschall in Med 2018; 39: e2-e44
• 12 Dassen S, Monen L, Oei G. et al. Safety of contrast-enhanced ultrasound using microbubbles in human pregnancy: A scoping review. Ultraschall in Med 2025; 46: 259-269
• 13 Sidhu PS, Huang DY, Fang C. Contrast enhanced ultrasound (CEUS) in Pregnancy: Is this the last frontier for microbubbles?. Ultraschall in Med 2020; 41: 8-11
• 14 Schwarze V, Marschner C, Negrão De Figueiredo G. et al. Single-Center Study: Evaluating the Diagnostic Performance and Safety of Contrast-Enhanced Ultrasound (CEUS) in Pregnant Women to Assess Hepatic Lesions. Ultraschall in Med 2020; 41: 29-35
• 15 Schwarze V, Froelich MF, Marschner C. et al. Safe and pivotal approaches using contrast-enhanced ultrasound for the diagnostic workup of non-obstetric conditions during pregnancy, a single-center experience. Arch Gynecol Obstet 2021; 303: 103-112
• 16 Schwarze V, Marschner C, Negrão De Figueiredo G. et al. SonoVue Does Not Appear to Cross the Placenta as Observed During an Examination Aimed at Confirming a Diagnosis of Liver Echinococcosis in a Pregnant Woman. Ultraschall in Med 2020; 41: 146-147
• 17 Denbow ML, Welsh AW, Taylor MJ. et al. Twin Fetuses: Intravascular Microbubble US Contrast Agent Administration – Early Experience. Radiology 2000; 214: 724-728
• 18 Tang C, Fang K, Guo Y. et al. Safety of Sulfur Hexafluoride Microbubbles in Sonography of Abdominal and Superficial Organs: Retrospective Analysis of 30,222 Cases. J of Ultrasound Medicine 2017; 36: 531-538
• 19 Jain A, Dhande RP, Parihar PH. et al. Contrast-enhanced ultrasound for fetal and placental assessment: evidence, safety, and a roadmap for clinical translation. Ultrasound J 2025; 17: 43
• 20 Sidhu PS, Clevert DA, Deganello A. et al. Controversies in contrast-enhanced ultrasound (CEUS): pregnancy, paediatric, abdominal trauma, complex renal cysts, and endovascular aortic repair follow-up. Insights Imaging 2025; 16
• 21 Kollmann C, Jenderka K-V, Moran CM. et al. EFSUMB Clinical Safety Statement for Diagnostic Ultrasound – (2019 revision). Ultraschall in Med 2020; 41: 387-389
• 22 Nelson CP, Sanda MG. Contemporary Diagnosis and Management of Renal Angiomyolipoma. Journal of Urology 2002; 168: 1315-1325
• 23 Dipinto P, Canale V, Minelli R. et al. Qualitative and quantitative characteristics of CEUS for renal cell carcinoma and angiomyolipoma: a narrative review. J Ultrasound 2024; 27: 13-20
• 24 Wang C, Yu C, Yang F. et al. Diagnostic accuracy of contrast-enhanced ultrasound for renal cell carcinoma: a meta-analysis. Tumor Biol 2014; 35: 6343-6350
• 25 Geyer T, Schwarze V, Marschner C. et al. Diagnostic Performance of Contrast-Enhanced Ultrasound (CEUS) in the Evaluation of Solid Renal Masses. Medicina 2020; 56: 624
• 26 Tufano A, Drudi FM, Angelini F. et al. Contrast-Enhanced Ultrasound (CEUS) in the Evaluation of Renal Masses with Histopathological Validation – Results from a Prospective Single-Center Study. Diagnostics 2022; 12: 1209
• 27 Wei S-P, Xu C-L, Zhang Q. et al. Contrast-enhanced ultrasound for differentiating benign from malignant solid small renal masses: comparison with contrast-enhanced CT. Abdom Radiol 2017; 42: 2135-2145
• 28 Furrer MA, Spycher SCJ, Büttiker SM. et al. Comparison of the Diagnostic Performance of Contrast-enhanced Ultrasound with That of Contrast-enhanced Computed Tomography and Contrast-enhanced Magnetic Resonance Imaging in the Evaluation of Renal Masses: A Systematic Review and Meta-analysis. European Urology Oncology 2020; 3: 464-473
• 29 Müller-Peltzer K, Rübenthaler J, Negrao De Figueiredo G. et al. CEUS – Diagnostik benigner Leberläsionen. Radiologe 2018; 58: 521-527
• 30 Kaltenbach TE-M, Engler P, Kratzer W. et al. Prevalence of benign focal liver lesions: ultrasound investigation of 45,319 hospital patients. Abdom Radiol 2016; 41: 25-32
• 31 Xie X-H, Xu H-X, Xie X-Y. et al. Differential diagnosis between benign and malignant gallbladder diseases with real-time contrast-enhanced ultrasound. Eur Radiol 2010; 20: 239-248
• 32 Bremme KA. Haemostatic changes in pregnancy. Best Practice & Research Clinical Haematology 2003; 16: 153-168
• 33 Konkle BA. Diagnosis and management of thrombosis in pregnancy. Birth Defects Research Pt C 2015; 105: 185-189
• 34 Rafailidis V, Fang C, Yusuf GT. et al. Contrast-enhanced ultrasound (CEUS) of the abdominal vasculature. Abdom Radiol (NY) 2018; 43: 934-947
• 35 Piscaglia F, Cucchetti A, Terzi E. et al. Validation of noninvasive methods for the assessment of liver fibrosis in patients with recurrent hepatitis C after transplantation. Liver Transplantation 2010; 16: 1006-1007
• 36 Tarantino L, Francica G, Sordelli I. et al. Diagnosis of benign and malignant portal vein thrombosis in cirrhotic patients with hepatocellular carcinoma: color Doppler US, contrast-enhanced US, and fine-needle biopsy. Abdom Imaging 2006; 31: 537-544
• 37 Song Z-Z, Huang M, Jiang T-A. et al. Diagnosis of portal vein thrombosis discontinued with liver tumors in patients with liver cirrhosis and tumors by contrast-enhanced US: A pilot study. European Journal of Radiology 2010; 75: 185-188
• 38 Dănilă M, Sporea I, Popescu A. et al. The value of contrast enhanced ultrasound in the evaluation of the nature of portal vein thrombosis. Med Ultrason 2011; 13: 102-107
• 39 Patil AS, Sheng JS, Dotters-Katz SK. et al. Principles of Anti-infective Dosing in Pregnancy. Clinical Therapeutics 2016; 38: 2006-2015
• 40 Grant A, Bai K, Badalato GM. et al. Advances in the Treatment of Urinary Tract Infection and Bacteriuria in Pregnancy. Urologic Clinics of North America 2024; 51: 571-583
• 41 Fontanilla T, Minaya J, Cortés C. et al. Acute complicated pyelonephritis: contrast-enhanced ultrasound. Abdom Imaging 2012; 37: 639-646

Publication History

Received: 03 November 2025

Accepted after revision: 04 January 2026

Article published online:
10 February 2026