Positron-emission tomography magnetic resonance imaging (PET/MRI) has emerged as a powerful hybrid molecular imaging technique in clinical practice, overcoming initial technical challenges to provide comprehensive anatomic and metabolic information. This advanced modality combines the superior soft tissue contrast of MRI with the metabolic insights of PET, offering advantages in hepatobiliary imaging, including improved detection of small liver metastases and reduced radiation exposure. The evolution of PET/MRI technology has been marked by significant advancements, such as the development of MRI-compatible PET detectors and sophisticated motion compensation techniques. These innovations have enhanced image quality and co-registration accuracy, crucial for hepatobiliary imaging. The integration of time-of-flight capability and silicon photomultipliers has further improved spatial resolution and sensitivity. PET/MRI protocols for liver imaging typically involve a whole-body scan followed by a targeted liver examination, utilizing radiotracers like FDG and DOTATATE. This approach allows for comprehensive staging and detailed liver assessment in a single session, potentially altering management decisions in up to 30% of patients with intrahepatic cholangiocarcinoma. While PET/MRI excels in characterizing various hepatobiliary lesions, including hepatocellular carcinoma and cholangiocarcinoma, challenges remain in differentiating certain benign entities like small hemangiomas from metastases. Ongoing research and clinical experience continue to refine the role of PET/MRI in hepatobiliary imaging, promising improved diagnostic accuracy and patient care.

Lymphedema is a chronic condition marked by swelling in the body’s soft tissues due to impaired or damaged lymphatic function. Lymphedema is estimated to affect about 1 in 1000 in the United States and 1.4 per 1000 based on two European studies. Lymphedema diagnosis relies on clinical visual assessment by physicians, and the quantitative evaluation of lymphatic function is not widely employed due to the lack of standardized and validated metrics. Lymphoscintigraphy is considered the practical gold standard for evaluating lymphedema. With the emergence of advanced surgical therapies, there is a growing demand for quantitative evaluation metrics to objectively evaluate treatment response. To address this unmet need, we reviewed various methods of quantitative lymphoscintigraphy (qLSG) that were used for assessing lymphedema. We found that multiple qLSG approaches have been described. Moreover, the protocols vary widely in terms of tracer type, injection route, dosage, and exercise interventions. We compared the quantitative assessment strategies and highlighted the approaches that may help provide a more objective lymphedema diagnosis and follow-up.

Lower extremity swelling has a broad differential diagnosis, including lymphedema, obesity-induced lymphedema, phlebolymphedema, and lipedema. Although these conditions may appear similar clinically, their pathophysiology and lymphoscintigraphic findings differ. Obesity, venous insufficiency, and abnormal adipose tissue can complicate image interpretation. We present four representative cases to illustrate characteristic imaging patterns across these conditions. These cases highlight the importance of interpreting lymphoscintigraphy in a clinical context.