1. An imaging agent for a cell and / or tissue characterized by fibrosis, comprising a retinoid and a detectable label. ! 2. The imaging agent according to claim 1, containing a polymer conjugate containing at least one repeating unit selected from formulas (I), (II), (III) and (IV):! [Schemes. 1] ! ! ! where m means independently 1 or 2； ! n is independently 1 or 2； ! A1 and A2 each independently mean oxygen or NR7； ! A3 and A4 each independently mean oxygen or NR8； ! A5 and A6 each independently mean oxygen or NR9； ! R1, R2, R3, R4, R5 and R6 are each independently selected from the group consisting of optionally substituted C1-10 alkyl, optionally substituted C6-20 aryl, ammonium, alkali metal, retinoid, and a group that contains a detectable label； ! R7, R8 and R9 are each independently hydrogen or C1-4 alkyl； ! o, p, q and r each independently are 0, 1 or more, where the sum of o, p, q and r means 2 or more； and! with the proviso that at least one of R1, R2, R3, R4, R5 and R6 is a group that contains a detectable label, and at least one of R1, R2, R3, R4, R5 and R6 is a retinoid. ! 3. The imaging agent according to claim 1 or 2, wherein the retinoid contains retinol. ! 4. The imaging agent according to claim 1 or 2, wherein the imaging agent is used for in vivo imaging. ! 5. The imaging agent according to claim 1 or 2, where the imaging agent is used to visualize fibrotic disease. ! 6. A polymer conjugate containing at least one repeating unit selected from formulas (I), (II), (III) and (IV):! [Schemes. 2]! ! ! where m means independently 1 or 2； ! n is independently 1 or 2； ! A1 and A2 each independently mean oxygen or NR7； ! A3 and A4 each independently mean oxygen or NR8； !1. Визуализирующий агент для клетки и/или ткани, характеризующихся фиброзом, содержащий ретиноид и детектируемую метку. ! 2. Визуализирующий агент по п.1, содержащий полимерный конъюгат, содержащий по меньшей мере одно повторяющееся звено, выбранное из формул (I), (II), (III) и (IV): ! [
