nuclear magnetic resonance

resonance /res·o·nance/ (rez´o-nins)

1. the prolongation and intensification of sound produced by transmission of its vibrations to a cavity, especially such a sound elicited by percussion.

2. a vocal sound heard on auscultation.

3. the existence of organic chemical structures that can not be accurately represented by a single structural formula, the actual formula lying intermediate between several possible representations differing only in electron position.

---

amphoric resonance  an auscultatory sound like that produced by blowing over the mouth of an empty bottle.

nuclear magnetic resonance  a measure, by means of applying an external magnetic field to a solution in a constant radiofrequency field, of the magnetic moment of atomic nuclei to determine the structure of organic compounds; the technique is used in magnetic resonance imaging.

skodaic resonance  increased percussion resonance at the upper part of the chest, with flatness below it.

tympanitic resonance 

1. the percussion sound heard on an abdomen with tympanites.

2. the drumlike reverberation of a cavity full of air.

vocal resonance  (VR) the sound of ordinary speech as heard through the chest wall.

---

nuclear magnetic resonance

n.

Abbr. NMR The absorption of electromagnetic radiation of a specific frequency by an atomic nucleus that is placed in a strong magnetic field, used especially in spectroscopic studies of molecular structure and in medicine to measure rates of metabolism.

---

nuclear magnetic resonance.

See magnetic resonance.

---

nuclear magnetic resonance,

n See magnetic resonance imaging.

---

nuclear magnetic resonance

See Magnetic resonance imaging, NMR.

Nuclear magnetic resonance

Diagnostic NM  

• In vivo–eg injection of radiocontrast to detect an ↑/↓ in local 'signal'–uptake in suspected bone metastases

• In vitro–assays of clinical specimens, eg radio immunoassay–RIA for various hormones, eg human chorionic gonadotropin–β-HCG, insulin, and TSH

Therapeutic NM Radiation oncology Administration of a 'hot' isotope to sterilize a particular area, and prevent malignant cells from growing & dividing

Note: RIAs are being replaced by ELISAs, which are easier to perform, the reagents are more easily stored, and do not have the problems inherent in using and disposing of radioactive waste; nuclear medicine also encompasses in vivo diagnostics in the form of scintillation counters to 'scan' various body regions for the presence of increased uptake of radionuclides, which when focal, implies primary neoplasia or metastases