SUper-Resolution Ultrasound Imaging of Erythrocytes (SURE) in Normal and Malignant Lymph Nodes

The goal of this observational study is to visualize the small vessels in normal and cancerous lymph nodes on the neck with a new ultrasound technique.

The main questions it aims to answer are:

* Is it possible to visualize the network of the smallest vessels in lymph nodes on the neck?
* Is it possible to distinguish between healthy and cancerous lymph nodes using different parameters?

The participants will have 1-2 lymph nodes ultrasound scanned with a standard ultrasound technique and the new technique.

Super-resolution ultrasound using erythrocytes (SURE) is a new ultrasound technique for visualizing the very small blood vessels in the body. The technique uses tracking of the blood's red blood cells (erythrocytes) to achieve a higher resolution of the blood vessels' shape, structure, and blood flow. The technique makes it possible to create images with much higher resolution than normal ultrasound, which means that even very small blood vessels can be imaged and measured.

In many diseases, the small blood vessels change their function or structure. One of the major disease groups where SURE has significant potential is cancer. In cancerous nodes, the small blood vessels change: they become twisted, irregular, and function poorly. If changes in the small vessels can be detected at an early stage using SURE, it can lead to quicker diagnoses and better evaluations of the effectiveness of treatment.

In this study, the investigators aim to demonstrate the practical feasibility of SURE imaging in human lymph nodes and investigate the clinical relevance of SURE imaging in the diagnosis of malignant lymph nodes by comparing lymph nodes from healthy participants with lymph nodes from participants with head and neck cancer metastases or lymphoma.

Eligibility Criteria:
Inclusion Criteria:

* Participants must be 18 to 70 years of age, at the time of signing the informed consent
* Participants who can lie still for 1 minute
* Capable of giving signed informed consent

Inclusion criteria for healthy participants:

* Participants who are overtly healthy as determined by medical history
* Participants who have a superficial lymph node laterally on the neck with a normal appearance on standard B-mode ultrasound available for SURE imaging

Inclusion criteria for participants with head and neck cancer or lymphoma:

* Participants who, besides their untreated head and neck cancer or lymphoma, are overtly healthy as determined by medical evaluation and medical history
* Participants with untreated lymphoma or head and neck cancer and lymph node metastasis verified by a biopsy.
* Participants who have superficial lymph nodes laterally on the neck up to 2.5 cm (so the entire lymph node is in the SURE image)
* Participants who will have their lymph nodes surgically removed

Exclusion Criteria:

* Pregnancy
* Dementia
* Physique making ultrasound scanning difficult
* Ongoing or recent (within the last 4 weeks) infectious disease (bacterial, viral, fungal, or protozoal) which may give rise to reactive lymph nodes
* Diseases that cause lymphadenopathy: Some chronic infectious diseases (HIV, Tuberculosis, Hepatitis B), Systemic diseases (rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis, other rare systemic diseases\*), Primary adrenal insufficiency (Addison´s disease), Leukemia, Lymphoma or other cancers (besides the type of cancer the participant is being examined for at the Department of Otorhinolaryngology, Head and Neck Surgery \& Audiology, Rigshospitalet)
* Drugs that cause lymphadenopathy: Antibiotics (Cephalosporins, Penicillin, Sulfonamides), Antiepileptics (Carbamazepine, Ethosuximide, Lamotrigine, Phenytoin, Primidone), Antihypertensives (Atenolol, Captopril, Hydralazine), Other (Allopurinol, Imatinib)

  * Castleman's disease, Kikuchi's disease, Kawasaki disease, Inflammatory pseudotumor, Amyloidosis, Kimura disease, Rosai-Dorfman disease, IgG4-related disease, Still's disease, dermatomyositis, Churg-Strauss, histiocytosis, chronic granulomatous diseases, Autoimmune lymphoproliferative syndrome, lipid storage diseases.