The research team, led by Lili Liu and Dezhi Zhang, analysed 87 necrotic liver lesions in 81 consecutive patients scanned between December 2014 and March 2018. The group included 32 men and 49 women with a mean age of 51.2 years. Rather than relying on a single diagnostic method, the investigators confirmed each diagnosis through a layered approach: histopathology in eight cases, contrast-enhanced CT or MRI combined with follow-up in thirteen, and ultrasound follow-up in the remaining sixty. This careful case mix gave the team a rare window into one of hepatology’s most enigmatic findings.

The star technology of the study is contrast-enhanced ultrasound, or CEUS, a technique that injects microscopic gas-filled bubbles into the bloodstream and tracks them in real time as they flood through liver tissue. Because these microbubbles remain confined to blood vessels, they act as exquisitely sensitive tracers of perfusion. A malignant tumour, hungry for blood, lights up and fades in characteristic patterns; a dead, avascular nodule stays stubbornly dark. The technique involves no ionising radiation and can be performed at the bedside, making it an attractive first-line tool in liver lesion work-ups worldwide.

What the Chinese team found was strikingly consistent. The lesions, with a median diameter of 26 millimetres and a range from 7 to 60 millimetres, were overwhelmingly irregular in shape: 77.0 percent, or 67 of the 87 lesions, lacked a clean round outline. Among these, 55 displayed a tortuous, cord-like configuration, resembling twisted strands rather than compact masses. Even more intriguing was a subtle sign on conventional grey-scale ultrasound: central hyperechoic foci, bright echoes tucked into the middle of the lesion, arranged in patterns the authors describe as equal-sign-like or core-type, which appeared in 18.4 percent of nodules.

On CEUS, the nodules split cleanly into two behavioural camps. Just over half, 55.2 percent, showed no enhancement whatsoever in any phase of the contrast study, a signature of truly dead, bloodless tissue. The remaining 44.8 percent displayed an arterial-phase rim of hyperenhancement around a persistently dark centre, suggesting a living inflammatory or fibrous border wrapped around the necrotic core. The median thickness of that enhancing rim was 3.1 millimetres, but in 11 of the 39 rim-enhancing lesions, more than a quarter of the group, the rim measured 5 millimetres or thicker.

That rim thickness turned out to be far more than a curiosity. Lesions with thick rims were dramatically more likely to show washout of contrast during the portal venous phase, occurring in 45.5 percent of thick-rim lesions compared with just 3.6 percent of the rest, a statistically significant association with a phi correlation coefficient of 0.522. Washout, the fading of contrast from a lesion after its initial uptake, is classically an ominous sign associated with malignancy, particularly hepatocellular carcinoma. Knowing that a benign necrotic nodule can produce the same behaviour when its fibrous border is thick could spare patients unnecessary alarm and invasive procedures.

The shape of the nodule itself also carried diagnostic information. Round-like lesions were far more likely than irregular ones to contain central microcystic structures, seen in 25.0 percent versus none of the irregular lesions, a difference that was highly significant with a phi value of 0.452. They were also far likelier to harbour those central hyperechoic foci, present in 60.0 percent of round lesions compared with only 6.0 percent of irregular ones. Additionally, thick-rim lesions underwent appreciable enlargement of their apparent size after contrast injection in 72.7 percent of cases, against 28.6 percent of thin-rim lesions, reflecting the way an enhancing rim dramatically redefines the visible boundary of a lesion.

Statistically, the team subjected their data to rigorous analysis. Two blinded radiologists independently reviewed every conventional ultrasound and CEUS study, with disagreements settled by a senior radiologist in consensus sessions. Group comparisons employed chi-square and Fisher’s exact tests for categorical variables, t-tests and the Mann-Whitney U test for continuous data, and the phi coefficient to quantify the strength of associations between imaging features. The ethics committee of the First Hospital of Jilin University approved the retrospective design and waived the requirement for individual written consent, in line with the Declaration of Helsinki.

The clinical stakes are considerable. A solitary lesion discovered in the liver triggers an anxious differential diagnosis that spans metastatic cancer, hepatocellular carcinoma, abscess, haemangioma and focal nodular hyperplasia. Solitary necrotic nodules, which are thought to arise from prior injury, infection, or vascular insult that leaves behind a coagulated island of dead hepatocytes, sit benignly within this list but frequently masquerade as something sinister. Misreading one can lead to biopsies, surgeries and months of surveillance; mistaking a tumour for one can be catastrophic. Precise imaging criteria are therefore not an academic luxury but a direct safeguard for patients.

The authors conclude that solitary necrotic nodules do exhibit characteristic ultrasound and CEUS features, and that a tortuous cord-like morphology combined with central equal-sign-like echogenic foci may actively support the diagnosis. Their observation that a thick arterial rim of 5 millimetres or more correlates with pronounced portal-phase washout and a visible increase in lesion size after contrast offers what they call a novel exploratory perspective on the imaging characterisation of these nodules, one they argue deserves clinical attention. As contrast-enhanced ultrasound continues its global expansion, studies like this one are quietly transforming the humble ultrasound suite into one of the most powerful diagnostic arenas in modern medicine.

Subject of Research: Contrast-enhanced ultrasound characterization of solitary necrotic nodules of the liver

Article Title: Solitary necrotic nodule of the liver: a single-centre retrospective CEUS study of 87 lesions

Article References: Liu, L., Zhou, Y., Li, J., Wang, D., Sui, M., Zhu, Y., Chen, C., He, H., & Zhang, D. (2026). Solitary necrotic nodule of the liver: a single-centre retrospective CEUS study of 87 lesions. BMC Medical Imaging. https://doi.org/10.1186/s12880-026-02796-0

Image Credits: AI Generated

DOI: 10.1186/s12880-026-02796-0

Keywords: liver, solitary necrotic nodule, contrast-enhanced ultrasound, CEUS, radiology, diagnostic imaging, washout, hepatocellular carcinoma, ultrasound, necrosis, BMC Medical Imaging, Solitary

The study, led by Meili Yu and colleagues at the Affiliated Taian City Central Hospital of Qingdao University, enrolled 32 patients with central-type lung cancer complicated by atelectasis who had either contraindications to bronchoscopy or in whom the procedure had failed. All were scanned and biopsied under contrast-enhanced ultrasound guidance between February 2022 and February 2025. The central question was deceptively simple: on a grayscale ultrasound image, can you actually tell where the tumor ends and the collapsed lung begins? If you cannot, any needle trajectory is a guess, and a guess that samples collapsed, inflamed, or necrotic tissue yields a false negative or a useless specimen.

The answer to that question is where the technique earns its keep. With conventional ultrasound alone, the interface between tumor and adjacent atelectatic lung was visible in only 40.6 percent of the patients, meaning that in nearly six out of ten cases the operator was effectively navigating blind. After an intravenous injection of an ultrasound contrast agent, that display rate jumped to 96.9 percent. In the 31 patients in whom the tumor-lung interface became clearly delineated, the enhancement dynamics themselves carried diagnostic information, because tumor tissue and collapsed lung tissue perfuse at measurably different speeds and with different patterns.

Those dynamics follow a consistent physiological logic. Lung cancers of the central type draw their blood supply from the bronchial arterial circulation, and the study found that all of the malignant lesions began to enhance between 10 and 17 seconds after contrast injection. The atelectatic lung, by contrast, is fed largely by the pulmonary arterial system, and in 80.7 percent of cases, 25 of the 31 evaluable patients, the collapsed tissue lit up earlier than the tumor. That timing difference gives the operator a real-time map: the region that enhances late is the tumor, the region that enhances early is the collapsed lung, and the needle can be steered toward the late-enhancing territory with a confidence that grayscale imaging cannot provide.

The enhancement pattern over time added a second layer of discrimination. In 83.9 percent of patients, 26 of 31, the central tumors showed what radiologists describe as a slow-in, fast-out pattern: contrast arrived late relative to the surrounding collapsed lung and then washed out quickly, a signature of the disorganized, arteriovenous-shunting microvasculature typical of malignant tissue. In 90.3 percent of lesions, 28 of 31, the tumor ultimately appeared hypo-enhanced relative to the reference tissue, reflecting the relatively sparse and abnormal vessel density within the tumor mass compared with the hyperemic collapsed lung around it. Together, the timing, the washout behavior, and the relative intensity form a composite target signature that the operator can follow on screen.

The technique also exposed a complication that would otherwise sabotage the biopsy silently. In nine patients, 28.1 percent of the cohort, the contrast scan revealed entirely non-enhancing areas within the lesion, corresponding to necrotic tissue where no viable tumor cells would be found. Sampling a necrotic core is one of the classic causes of non-diagnostic biopsies, and conventional imaging frequently cannot distinguish necrosis from viable tumor. By marking the non-enhancing zones in real time, the CEUS approach allowed the operators to aim for the enhancing, viable rim instead, which is precisely the material a pathologist needs to render a definitive diagnosis.

The bottom line for the 31 patients with a clearly visualized target was unambiguous: every single one underwent a successful puncture and yielded a definite pathological diagnosis. In a population defined by the failure or impossibility of the standard first-line diagnostic route, a 100 percent diagnostic sampling rate is a striking result. Equally important for a technique that involves passing a needle through the chest wall toward the mediastinum, the study reported no severe puncture-related complications, suggesting that the real-time vascular mapping provided by contrast enhancement does not merely improve yield but may also contribute to procedural safety by keeping the needle away from vessels and necrotic cavities.

Placed in context, the findings address a genuine clinical bottleneck. Central-type lung cancers arise in the large central airways, where bronchoscopic visualization and forceps biopsy are normally straightforward, which is why bronchoscopy dominates diagnostic algorithms for this tumor location. But the same tumors frequently obstruct the bronchus enough to collapse the downstream lung, and the resulting atelectasis creates a consolidated, fluid-filled region on ultrasound that can look remarkably similar to the tumor itself. Patients who cannot be bronchoscoped, whether because of respiratory failure, coagulopathy, vascular anatomy, or a failed attempt, have historically faced repeated attempts, more invasive surgical biopsies, or empiric treatment without histology. A percutaneous, ultrasound-guided alternative that works at the bedside, avoids ionizing radiation, and exploits the perfusion contrast between tumor and collapsed lung offers a pragmatic escape route.

The study’s design and scale warrant measured interpretation. It was retrospective, single-center, and involved 32 patients over a three-year window, and the authors themselves frame the work as an exploration of diagnostic value rather than a definitive trial. Selection is a consideration: these were patients in whom the technique was attempted, and the learning curve for CEUS-guided thoracic biopsy is real, since the operator must interpret contrast kinetics in real time while advancing a needle. The enhancement timings reported here, with tumors enhancing at 10 to 17 seconds and atelectatic lung typically earlier, provide a useful reference range, but they derive from one institution’s experience with one contrast agent and one scanner platform. Broader, ideally prospective, multicenter validation would be needed before the approach becomes a standard recommendation in guidelines.

Even with those caveats, the study adds a technically elegant tool to a problem that has few good answers. Contrast-enhanced ultrasound is inexpensive relative to CT or PET guidance, portable enough to be performed in an interventional suite or at the bedside, and free of the radiation burden of repeated CT-guided passes. By converting the perfusion differences between a tumor and the collapsed lung surrounding it into a visible, time-resolved map, the technique turns a previously ambiguous grayscale field into a target with defined borders, defined timing, and defined zones of viability. For the subset of lung cancer patients who are too sick or too difficult to bronchoscope, that transformation may be the difference between a specimen that changes treatment and a diagnostic dead end. The Taian team’s data, showing near-universal interface visualization, consistent tumor enhancement signatures, and complete diagnostic success without severe complications, make a credible case that CEUS-guided percutaneous biopsy deserves a defined place in the diagnostic algorithm for central lung cancer with atelectasis.

Subject of Research: Contrast-enhanced ultrasound-guided percutaneous biopsy for diagnosing central-type lung cancer with atelectasis in patients with bronchoscopy contraindications or failure

Article Title: Application of Contrast-Enhanced Ultrasound (CEUS)-guided percutaneous biopsy in the diagnosis of central-type lung cancer patients with bronchoscopy contraindications or failed

Article References: Yu, M., Zheng, Y., Zhang, M., Wang, L., Lyu, G., Zhang, C., & Liu, B. (2026). Application of Contrast-Enhanced Ultrasound (CEUS)-guided percutaneous biopsy in the diagnosis of central-type lung cancer patients with bronchoscopy contraindications or failed. BMC Medical Imaging. https://doi.org/10.1186/s12880-026-02840-z

Image Credits: AI Generated

DOI: 10.1186/s12880-026-02840-z

Keywords: contrast-enhanced ultrasound, CEUS, lung cancer, central-type lung cancer, atelectasis, percutaneous biopsy, bronchoscopy, tumor-lung interface, interventional radiology, cancer imaging, diagnostic biopsy, BMC Medical Imaging