The disclosed embodiments include in-line inspection devices, methods to perform in-line inspections of pipeline and protective casings, and methods to determine anomalies of pipeline and protective casings. The method includes deploying an in-line inspection device in a section of a pipeline enclosed by a protective casing. While the in-line inspection device is traveling along the pipeline, the method also includes transmitting, at a frequency, a transmitted signal toward the protective casing; and detecting a scattered signal scattered by the protective casing. The method further includes detecting a scattered signal scattered by the protective casing. The method further includes locating an anomaly of the protective casing based on the scattered signal.