Contrast-enhanced ultrasound reveals perfusion differences between benign lipoma and semi-malignant atypical lipomatous tumors: A prospective clinical study

Abstract

Purpose Soft tissue tumors (STT) are difficult to diagnose accurately, and distinguishing between benign and malignant tumors is challenging. Lipoma is the most common STT, while atypical lipomatous tumors (ALT) can dedifferentiate into malignant lipomatous tumors like grade 1 liposarcoma and require more radical therapy. This study aims to investigate the potential of contrast-enhanced ultrasound (CEUS) to differentiate between lipoma and ALT based on tumor perfusion.

Materials and Methods We prospectively examined 52 patients who were scheduled for biopsy for suspected lipoma or ALT. The CEUS examination was performed using SonoVue as a contrast agent to quantify tumor perfusion using VueBox V7.1 software. Peak enhancement (PE), rise time (RT), wash-in perfusion index (WiPI), and wash-out rate (WoR) were used to assess contrast enhancement inside the STT.

Results Among 50 tumors examined, 30 were lipomas, and 20 were ALTs. We found significant differences in perfusion between lipomas and ALTs (PE: 49.22 ± 45.75 a.u. vs. 165.67 ± 174.80; RT: 23.86 ± 20.47s vs. 10.72 ± 5.34 s; WiPI: 33.06 ± 29.94 dB vs. 107.21 ± 112.43 dB; WoR: 2.44 ± 3.70 dB/s vs. 12.75 ± 15.80 dB/s; p<.001). ROC analysis of PE resulted in a diagnostic accuracy of 74% for the detection of an ALT, and 77% for the detection of a lipoma.

Conclusion CEUS may enhance the differential diagnosis of benign lipomas and ALTs, with ALTs showing higher levels of perfusion. If larger prospective studies confirm these findings, CEUS could enhance diagnostic accuracy, guide surgical planning, and potentially reduce unnecessary treatments for patients presenting with ambiguous lipomatous tumors like lipoma or ALT.

Zusammenfassung

Ziel Die Unterscheidung zwischen gutartigen und bösartigen Weichteiltumoren gestaltet sich oftmals herausfordernd. Insbesondere benigne Lipome lassen sich nur schwer von semimalignen atypischen lipomatösen Tumoren (ALT) abgrenzen, welche in bösartige Liposarkome entdifferenzieren können. Diese Studie untersucht die Qualität des kontrastmittelverstärkten Ultraschalls (CEUS) zur Unterscheidung von Lipomen und ALT anhand der Tumor-Mikroperfusion.

Material und Methoden 52 Patienten, bei denen bei Verdacht auf ein Lipom oder ALT eine Biopsie geplant war, wurden präoperativ mittels CEUS und MRT untersucht. Die CEUS-Tumorperfusion wurde mithilfe der Software VueBox V7.1 quantifiziert. Die Perfusionsparameter „Peak enhancement“ (PE), „rise time“ (RT), „wash-in perfusion index” (WiPI), und „wash-out rate“ (WoR) wurden zur Beurteilung der Mikroperfusion im Tumor verwendet.

Ergebnisse 30 Lipome und 20 ALTs wurden ausgewertet. Es zeigten sich signifikante Unterschiede der Perfusionskinetik zwischen beiden Tumoren (PE: 49,22 ± 45,75 a.u. vs. 165,67 ± 174,80; RT: 23,86 ± 20,47s vs. 10,72 ± 5,34 s; WiPI: 33,06 ± 29,94 dB vs. 107,21 ± 112,43 dB; WoR: 2,44 ± 3,70 dB/s vs. 12,75 ± 15,80 dB/s; p<.001). Die CEUS-Tumorperfusion ergab nach ROC-Analyse eine Testgenauigkeit von 77% für die Erkennung eines Lipoms und von 74% für die Erkennung eines ALT.

Schlussfolgerung Die CEUS-Perfusionsanalyse ist geeignet, um gutartige Lipome und semimaligne ALTs besser abzugrenzen. ALTs zeigten signifikant höhere Perfusionswerte als Lipome. Wenn größere prospektive Studien diese Ergebnisse bestätigen, könnte CEUS die präoperative Diagnostik und somit die individuelle Therapie sowie Operationsplanung verbessern.

Keywords

Lipoma - CEUS - perfusion - ALT

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