Acid-base homeostasis and pH regulation are critical for normal tissue metabolism and physiology, and brain tissue pH alters in many diseased states. Several noninvasive tissue pH Magnetic Resonance (MR) techniques have been developed over the past few decades to shed light on pH change during tissue function and dysfunction. Nevertheless, there are still challenges for mapping brain pH noninvasively at high spatiotemporal resolution. To address this unmet biomedical need, chemical exchange saturation transfer (CEST) MR techniques have been developed as a sensitive means for non-invasive pH mapping. This article briefly reviews the basic principles of different pH measurement techniques with a focus on CEST imaging of pH. Emerging pH imaging applications in the tumor are provided as examples throughout the narrative, and CEST pH imaging in acute stroke is discussed in the final section.

酸碱平衡和 pH 调节对于正常的组织代谢和生理机能至关重要，并且脑组织的 pH 在许多疾病状态下会发生变化。在过去的几十年中，已经开发了几种无创组织 pH 值磁共振 (MR) 技术，以阐明组织功能和功能障碍期间的 pH 值变化。尽管如此，在高时空分辨率下无创地绘制大脑 pH 值仍然存在挑战。为了解决这一未满足的生物医学需求，化学交换饱和转移 (CEST) MR 技术已被开发为一种用于非侵入性 pH 绘图的敏感手段。本文简要回顾了不同 pH 测量技术的基本原理，重点是 pH 的 CEST 成像。整个叙述中都提供了肿瘤中新兴的 pH 成像应用作为示例，