==================================BSR14================================== 14. Nuclear Magnetic Resonance: Dependence of relaxation times (T1 and T2) on temperature and field strength. 1 UI - 87116924 AU - P:ocsik I ; Fur:o I ; R:acz P TI - Freezing-thawing hysteresis. I. NMR detection in human lens. AB - Human eye lenses were investigated by 1H-NMR as a function of temperature around freezing. Wide hysteresis in line intensity and relaxation time has been found. The hysteresis behavior of the phase transition presents a useful possibility for investigating the structure of water in these materials. MH - Body Water/METABOLISM ; Freezing ; Human ; Lens, Crystalline/*METABOLISM ; Nuclear Magnetic Resonance ; Thermodynamics SO - Ophthalmic Res 1986;18(5):270-4 2 UI - 87063596 AU - Koenig SH ; Spiller M ; Brown RD 3d ; Wolf GL TI - Relaxation of water protons in the intra- and extracellular regions of blood containing Gd(DTPA). AB - The magnetic field dependence of the longitudinal relaxation rates 1/T1 (NMRD profiles) of blood and plasma from rabbits before and after injection of Gd(DTPA) are reported as a function of magnetic field strength from 0.01 to 50 MHz. Over 100 values along the time-dependent magnetization were recorded for each 1/T1 and analyzed for multiple exponentials. From these data, which indicate a single exponential, from the measured Gd content of each sample, and the NMRD profiles, we show that Gd is in the extracellular space only and is present as rotationally mobile Gd(DTPA), uncomplexed with protein or blood cells; and that the water protons exchange rapidly between the intra- and extracellular regions. MH - Animal ; *Contrast Media ; DTPA/BLOOD/*DIAGNOSTIC USE ; Male ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE ; Rabbits SO - Magn Reson Med 1986 Oct;3(5):791-5 3 UI - 87063591 AU - Hoult DI ; Chen CN ; Sank VJ TI - The field dependence of NMR imaging. II. Arguments concerning an optimal field strength. AB - Some of the factors involved in the choice of field strength for NMR imaging are examined. The influences of relaxation times and chemical shift upon image quality and signal-to-noise ratio are highlighted, and power deposition is introduced as a significant factor which may limit the flexibility and information available at higher fields as long as 180 degrees echo pulses continue to be necessary. Chemical-shift imaging is examined and found wanting as a means of coping with chemical-shift artifacts, and the use of multiple echoes (albeit with research) in conjunction with multiple-slice techniques is advocated as representing an efficient data-gathering scheme which can improve image signal-to-noise ratio. With such use, a medium field strength (0.5-1 T) is presented as representing, for general purpose imaging of head and torso, the best current compromise when imaging time is of major importance, with the important caveat that new techniques may always invalidate this conclusion. MH - Fourier Analysis ; Human ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/ METHODS SO - Magn Reson Med 1986 Oct;3(5):730-46 4 UI - 87063587 AU - Sperber GO ; Ericsson A ; Hemmingsson A ; Jung B ; Thuomas KA TI - Improved formulae for signal amplitudes in repeated NMR sequences: applications in NMR imaging. AB - An improved formalism describing the dependence of the signal strength on relaxation times and spin densities in pulsed nuclear magnetic resonance experiments is presented. It is especially applicable to repetitive experiments such as occur in imaging applications. Essentially, it includes long-time spin coherence effects not considered in the algorithms usually adopted. Also, some generalizations of classical concepts are made. Validity criteria are studied using numerical simulations. The algorithm assumes a relatively inhomogeneous main magnetic field, but the computer simulations indicate that the inhomogeneity normally present in magnetic resonance imagers is sufficient. The simulations also indicate that the field gradient pulses applied in the spatial encoding procedure do not necessarily interfere seriously with the validity of the formulae, but complicate the choice of optimal formula and may in some circumstances prevent the spin system from reaching a steady state. MH - *Algorithms ; Human ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/METHODS ; Support, Non-U.S. Gov't SO - Magn Reson Med 1986 Oct;3(5):685-98 5 UI - 87058318 AU - Sommer FG ; McNeal JE ; Carrol CL TI - MR depiction of zonal anatomy of the prostate at 1.5 T. AB - Previous reports of magnetic resonance imaging of the prostate have described a homogeneous appearance to the normal prostate gland. The T2-weighted images of the normal prostate obtained at higher field strength (1.5 T) reveal an inhomogeneous appearance of the normal gland, with apparent differentiation of normal prostatic zones having differing histology. The anterior fibromuscular tissue of the normal prostate, the glandular tissue comprising the central zone of the prostate, and the glandular tissue of the peripheral zone of the prostate can be differentiated by differences in intensity in the T2-weighted images. The ability to differentiate histologically distinct regions of the normal prostate may be important since clinically important prostatic diseases (benign prostatic hypertrophy and carcinoma) arise in different prostatic zones. MH - Adult ; Aged ; Comparative Study ; Human ; Male ; Middle Age ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/METHODS ; Prostate/*ANATOMY & HISTOLOGY ; Prostatic Diseases/DIAGNOSIS ; Reference Values ; Support, U.S. Gov't, P.H.S. ; Time Factors SO - J Comput Assist Tomogr 1986 Nov-Dec;10(6):983-9 6 UI - 87054039 AU - Chacko VP ; La Mar GN ; Gersonde K ; Sick H TI - Proton-magnetic-resonance investigation of the dynamics of the conformational transition in allosteric monomeric insect hemoglobins. AB - 1H-NMR spectra of the monomeric insect (Chironomus thummi thummi) hemoglobins CTT III and CTT IV were investigated in the pH range 5-10 to gain insight into the dynamics of the tense to relaxed (t in equilibrium r) conformational transition in the deoxy (at 200 MHz) and cyano-met (at 360 MHz) form. These hemoglobins exhibit a pH-sensitive O2 affinity (Bohr effect) which is linked to the conformational transition. Both hemoglobins are comprised of two components which show heme rotational disorder due to a 180 degrees rotation of the heme group about the alpha,gamma-meso axis. The heme rotational components differ remarkably in their Bohr effects [Gersonde, K. et al. (1986) Eur. J. Biochem. 157, 393-404]. Several of the hyperfine-shifted heme proton resonances in these hemoglobin derivatives show pH-induced line-broadening which is largest at pK = 7.46 (for the heme rotational component with large Bohr effect) or pK = 7.06 (for the heme rotational component with small Bohr effect) determined from the plots of chemical shift versus pH. The line broadening at pK approximately equal to 7.5, shown for the heme rotational component of cyano-met CTT IV with the largest Bohr effect, decreases in the following order in parallel with the pH-induced shift change: 4-H beta-c (1.20 ppm) greater than 3-CH3 (0.80 ppm) approximately greater than 4H alpha (0.76 ppm) approximately greater than 4H beta-t (0.73 ppm) greater than 8-CH3 (0.35 ppm). Decrease in temperature at the pK value also leads to line-broadening. At 4 degrees C the hyperfine-shifted resonance attributed to 3-CH3 is split into two resonances assigned to the t (low-pH form) and r (high-pH form) conformation, respectively. This temperature dependence confirms the t in equilibrium r exchange process as the origin of the pH-induced line-broadening. The Bohr proton exchange rate at the allosteric site is orders of magnitude larger than the t in equilibrium r exchange rate. Therefore, the proton-linked t in equilibrium r transition appears as a first-order reaction. The rate constant ktr for the t in equilibrium r transition at the pK in different hemoglobin derivatives ranges over 0.2-7 ms-1. Surprisingly, ktr is identical for deoxy and cyano-met CTT IV.(ABSTRACT TRUNCATED AT 400 WORDS) MH - Allosteric Regulation ; Animal ; Chironomidae/*ANALYSIS ; Diptera/ *ANALYSIS ; Heme/ANALYSIS ; Hemoglobins/*ANALYSIS ; Hydrogen-Ion Concentration ; Nuclear Magnetic Resonance ; Protein Conformation ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, Non-P.H.S. ; Support, U.S. Gov't, P.H.S. ; Temperature SO - Eur J Biochem 1986 Dec 1;161(2):375-81 7 UI - 87049889 AU - Kennedy SD ; Bryant RG TI - Manganese-deoxyribonucleic acid binding modes. Nuclear magnetic relaxation dispersion results. AB - Ion-DNA interactions are discussed and the applied magnetic field strength dependence of water proton spin-lattice relaxation rates is used to study the Mn(II)-DNA interaction both qualitatively and quantitatively. Associations in which the manganese II (Mn(II)) ion is completely immobilized on the DNA are identified as well as a range of associations in which the ion is only partially reorientationally restricted. Quantitative analysis of the strength of the association in which manganese is immobilized is carried out both with and without a counter-ion condensation correction for electrostatic attraction of the mobile ions. From competition experiments with manganese the relative strengths of the interactions of magnesium and calcium with DNA are found to be identical but less than that of manganese with DNA and the affinity of lithium for DNA is found to be slightly higher than that of sodium. The data demonstrate that the reduced mobility of nonsite-bound ions may have a significant effect on DNA-ion binding analyses performed using magnetic resonance and relaxation methods. MH - Animal ; Chemistry ; *DNA ; Kinetics ; *Manganese ; Mathematics ; Nuclear Magnetic Resonance/METHODS SO - Biophys J 1986 Oct;50(4):669-76 8 UI - 87045327 AU - Hamlin DJ ; Pettersson H ; Johnson JO ; Fitzsimmons JR TI - Advances in magnetic resonance imaging of the pelvis at 0.15 tesla. AB - The recent development of improved commercial radiofrequency coils and multiecho, multislice software for low field strength magnetic resonance systems has markedly increased the clinical utility of magnetic resonance imaging (MRI) of the pelvis at low field strengths. An evaluation of 70 patients with a variety of pelvic lesions and 14 normal volunteers who were studied using 0.15 T resistive magnet scanner revealed that anatomic structures and a variety of mass lesions could be clearly depicted in transaxial, sagittal and coronal planes using this updated system. Accurate characterization of lesions was possible in many instances using T2 weighted multiecho scans with echo time (TE) ranging from 30 ms to 120 ms (45 ms-180 ms using a reduced bandwidth technique). T1 weighted multislice scans demonstrated anatomic structures to best advantage and calculation of T1 and T2 relaxation times frequently facilitated more accurate differential diagnosis, particularly in the case of ovarian lesions. MH - Adnexitis/DIAGNOSIS ; Bladder Neoplasms/*DIAGNOSIS ; Bone Neoplasms/ DIAGNOSIS ; Female ; Genital Neoplasms, Female/*DIAGNOSIS ; Human ; Male ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE ; Pelvis/*ANATOMY & HISTOLOGY/PATHOLOGY ; Prostatic Neoplasms/*DIAGNOSIS ; Rectal Neoplasms/ DIAGNOSIS ; Sigmoid Neoplasms/DIAGNOSIS ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - Acta Radiol [Diagn] (Stockh) 1986 Jul-Aug;27(4):369-77 9 UI - 87037058 AU - Chin JL ; Stiller CR ; Karlik SJ TI - Nuclear magnetic resonance assessment of renal perfusion and preservation for transplantation. AB - The feasibility of using proton nuclear magnetic resonance (NMR) relaxation measurement to monitor organ perfusion and preservation was studied using a rat model. Intact kidneys were assessed with NMR following various periods of cold storage. Bilateral en bloc donor nephrectomy was performed on Sprague-Dawley rats with prior in situ flushing with Euro-collins', dextrose and other test solutions via a plastic cannula in the aorta. A paramagnetic agent, gadolinium-DPTA, dissolved in perfusion fluid was then injected into the renal vasculature. NMR analysis was repeated and the kidneys were reflushed with perfusion fluid to remove the gadolinium, followed by another NMR analysis. By sequential flushing and NMR measurement after 24, 48 and 72 hours of cold storage, the thoroughness of flushing, the patency of intrarenal vasculature and capillary integrity could be assessed. With the D5W, the T1 relaxation of kidneys dropped 56% with prolonged cold storage, indicating gadolinium accumulation in the interstitium, in effect loss of capillary integrity. With the Euro-collins', the T1 showed a small drop (23%) and almost complete flush-out, indicating superior tissue preservation and patency of vasculature. The addition of trifluoperazine, (TFP, a calmodulin inhibitor) to the Euro-collins' resulted in only a 9% drop in T1 after 72 hours. This possibly indicates TFP has additional protective action on cold ischemic damage. Using the small animal model presented here, proton NMR spectroscopy appears to be a sensitive technique in assessing renal vascular patency after cold storage and provides a useful tool for the investigation of other agents for organ preservation for transplantation. MH - Animal ; Cold ; Kidney/*TRANSPLANTATION ; Male ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE ; *Organ Preservation/METHODS ; *Perfusion ; Rats ; Rats, Inbred Strains ; Renal Circulation ; Support, Non-U.S. Gov't ; Time Factors SO - J Urol 1986 Dec;136(6):1351-5 10 UI - 87027413 AU - Richards MA ; Webb JA ; Reznek RH ; Davies G ; Jewell SE ; Shand WS ; Wrigley PF ; Lister TA TI - Detection of spread of malignant lymphoma to the liver by low field strength magnetic resonance imaging. AB - The accuracy of spin lattice relaxation time (T1) measurement obtained with a low field strength magnetic resonance imager for the detection of spread of malignant lymphoma to the liver was assessed. The results of histological examination obtained at open liver biopsy were compared with liver T1 values in 27 patients with lymphoma. The normal range for T1 was established by scanning 61 healthy volunteers. Magnetic resonance imaging was highly sensitive in detecting hepatic lymphoma, all seven patients with liver lymphoma proved by biopsy having considerably higher T1 values. Specificity was less good. Five out of 20 patients with no histological evidence of hepatic lymphoma had abnormal T1 values. this level of sensitivity is considerably better than that reported for other imaging methods and contrasts with the results of one previous study using a different magnetic resonance system. Low field strength magnetic resonance imaging may prove to be a useful screening test in patients with lymphoma. The presence of a normal liver T1 seems to be a reliable guide to the absence of hepatic disease. MH - Adolescence ; Adult ; Aged ; Human ; Liver Neoplasms/*DIAGNOSIS/PATHOLOGY ; Lymphoma/*DIAGNOSIS/PATHOLOGY ; Middle Age ; Neoplasm Invasiveness ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE ; Support, Non-U.S. Gov't SO - Br Med J [Clin Res] 1986 Nov 1;293(6555):1126-8 11 UI - 87000632 AU - Tollemar U ; Cunningham K ; Shriver JW TI - Lack of communication between LC2 light chain and the SH1 region of myosin S-1 studied by 19F-NMR. AB - Myosin subfragment-1 (S-1) which contains the LC2 light chain has been labelled with fluorine to allow an 19F-NMR study of the coupling and energetics of structural changes in the myosin head. Two fluorine-containing reagents, N-4-(trifluoromethyl)phenyl iodoacetamide and N-3,5-di(trifluoromethyl)phenyl iodoacetamide, have been used to label the myosin heavy chain at the unusually reactive sulfhydryl-1 (SH1) position. The chemical shift of both reagents on S-1 is sensitive to a structural transition in the region of SH1 which occurs upon increasing the temperature from 0 degrees C to 35 degrees C. The midpoint of the transition in both papain and chymotryptic S-1 is at approximately 11 degrees C at pH 7 (0.1 M CKl). The temperature dependence of the chemical shift may be fit assuming a two-state equilibrium where delta G degree' (T) = 101-110T +0.386 T2 (where T is the temperature in Kelvin). Both delta H degree' (T) and delta S degree' (T) have a small temperature dependence from 0 to 35 degrees C: at 20 degrees C, delta H degree' (T) = -33 kcal/mol. delta S degree' (T) = -116 e.u. and delta Cp = -226 cal/mol per deg (pH 7.0, 0.1 M KCl). The NMR data indicate that the presence of the LC2 light chain in papain S-1 does not modify the structure of S-1 in the vicinity of SH1, nor does it modify the energetics of the structural transition from that seen in its absence with chymotryptic S-1. The presence of calcium which is bound by the LC2 of papain S-1 also does not alter the energetics of the transition. Thus it would appear that the LC2 light chain (on myosin S-1) does not participate in the two-state transition, nor does it interact strongly with regions of the heavy chain which participate in the transition. MH - Adenosine Triphosphatase/METABOLISM ; Chemistry ; Chymotrypsin ; Myosin/ *PHYSIOLOGY ; Nuclear Magnetic Resonance ; Papain ; Peptide Fragments/ *PHYSIOLOGY ; Sulfhydryl Compounds ; Support, U.S. Gov't, P.H.S. ; Temperature ; Thermodynamics SO - Biochim Biophys Acta 1986 Sep 26;873(2):243-51 12 UI - 86269969 AU - Morariu VV ; Ionescu MS ; Frangopol M ; Grosescu R ; Lupu M ; Frangopol PT TI - The uptake of manganese ions and the apparent thermal transition of the erythrocyte membranes. AB - The nuclear magnetic resonance manganese doping technique is currently used for the determination of the water diffusional exchange time through human erythrocyte membranes. An apparent thermal transition at 26 degrees C was noticed at 18-30 mM manganese doping in the suspending solution. An analysis in terms of a two-phase nuclear spin exchanging system revealed that apparent thermal transitions are expected to occur in the upper and lower temperature regions. They represent a shift from intermediate exchange rates where water diffusion through the membrane is dominant to either fast or slow exchange rates where proton relaxation is the controlling process. The lower temperature apparent transition may be altered by the intracellular manganese concentration; the lower the Mn2+ concentration the lower the transition. Also according to this interpretation only a fraction of the erythrocytes are significantly permeated by Mn2+. The upper transition depends on the Mn2+ concentration in the extracellular volume; it decreases with decreasing Mn2+ concentration. MH - Chemistry, Physical ; Erythrocyte Membrane/*PHYSIOLOGY ; Human ; Manganese/*BLOOD ; Nuclear Magnetic Resonance ; Protein Binding ; Temperature ; Water/METABOLISM SO - Biochim Biophys Acta 1986 Aug 7;860(1):155-8 13 UI - 86265220 AU - Hecht-Leavitt C ; Gomori JM ; Grossman RI ; Goldberg HI ; Hackney DB ; Zimmerman RA ; Bilaniuk LT TI - High-field MRI of hemorrhagic cortical infarction. AB - High-field MRI is capable of differentiating acute, subacute, and chronic hemorrhagic cortical infarctions. In eight of nine patients, hemorrhage occurred in a vascular watershed zone. Acute hemorrhagic cortical infarction produces mild cortical low intensity on T2-weighted images outlined by subcortical edema (high intensity) and isointensity with normal cortex on T1-weighted images. Subacute hemorrhagic cortical infarction shows cortical high intensity first on T1-weighted images and later on T2-weighted images; it is also associated with subcortical edema. In the chronic stage, there is a marked persistent cortical low intensity on T2-weighted images. This is most prominent in the deeply infolded cortical gyri. The low intensity noted in acute and chronic hemorrhagic cortical infarction with T2 weighting appears to be related to two separate underlying histochemical states. The characteristic cortical low intensity observed on T2-weighted images in acute and chronic hemorrhagic cortical infarction is proportional to the square of the magnetic field strength. MH - Acute Disease ; Adolescence ; Adult ; Aged ; Cerebral Hemorrhage/ *DIAGNOSIS ; Cerebral Infarction/*DIAGNOSIS ; Child ; Child, Preschool ; Chronic Disease ; Female ; Hemoglobins/ANALYSIS ; Hemosiderin/ANALYSIS ; Human ; Male ; Methemoglobin/ANALYSIS ; Middle Age ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/METHODS SO - AJNR 1986 Jul-Aug;7(4):581-5 14 UI - 86265186 AU - Burk DL Jr ; Kanal E ; Brunberg JA ; Johnstone GF ; Swensen HE ; Wolf GL TI - 1.5-T surface-coil MRI of the knee. AB - Five normal knees and 20 knees with suspected abnormalities involving the menisci or articular surfaces were examined with high-resolution surface-coil MRI. Surgical correlation was available in 15 cases. Signal-to-noise ratios were optimized using a field strength of 1.5 T and a round 7.6-cm surface coil. Spatial resolution was maximized by using fields of view reduced to as small as 8 cm. Separate examinations of the medial and lateral joint compartments were performed with the surface coil positioned vertically adjacent to the meniscus of interest. Ten meniscal tears were identified using sagittal and coronal images. T1-weighted images were adequate to detect most meniscal tears, and T2-weighted images were useful for providing an "arthrogram effect: in the presence of a joint effusion. Extrameniscal lesions that were examined included osteonecrosis of the femoral condyle, subchondral cysts, rheumatoid arthritis, degenerative arthritis, and anterior cruciate ligament tears. MRI was useful in determining the integrity of articular cartilage overlying defects in the subchondral bone and in detecting gross cartilage lesions in arthritis, but was less sensitive than arthroscopy in evaluating moderate changes in the hyaline cartilage. MH - Arthritis, Rheumatoid/PATHOLOGY ; Cysts/PATHOLOGY ; Human ; Joint Diseases/*PATHOLOGY ; Knee Injuries/*PATHOLOGY ; Knee Joint/*ANATOMY & HISTOLOGY/PATHOLOGY ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/ INSTRUMENTATION ; Osteonecrosis/PATHOLOGY SO - AJR 1986 Aug;147(2):293-300 15 UI - 86260616 AU - Darwin RH ; Drayer BP ; Riederer SJ ; Wang HZ ; MacFall JR TI - T2 estimates in healthy and diseased brain tissue: a comparison using various MR pulse sequences. AB - Fourteen patients and five healthy individuals underwent magnetic resonance (MR) imaging to determine an effective multiple spin echo pulse sequence for estimating T2. Lesions examined included infarction, glioma, multiple sclerosis, and acute hematoma. A pulse repetition time (TR) of 1,500 msec and echo delays (TEs) of 25, 50, 75, and 100 msec were used. Computed T2 images were derived from all four echoes, the first two echoes, and the first and fourth echoes. T2 values were obtained from specific brain locales using region-of-interest analysis. Use of either the first two echoes or the first and fourth in the T2 fit provided T2 estimates which closely correlated with that of the four-echo analysis. The noise level in T2 maps constructed from the 25- and 100-msec echoes was modestly (typically 10%) higher than that from four echoes; noise level from the 25- and 50-msec echoes was markedly higher, typically 60%. This behavior is remarkably consistent with that predicted from theory. All 19 subjects displayed consistent relative T2 values for specific brain structures; in 13, the absolute T2 values fell within a limited range. Despite the high sensitivity of T2 images, their specificity in the detection of most brain disease appears limited except in acute intracerebral hematoma, which exhibited a decreased T2 relaxation time using high-field-strength MR imaging. MH - Adolescence ; Adult ; Brain Diseases/*DIAGNOSIS ; Brain Neoplasms/ DIAGNOSIS ; Cerebral Hemorrhage/DIAGNOSIS ; Cerebral Infarction/DIAGNOSIS ; Comparative Study ; Glioma/DIAGNOSIS ; Hematoma/DIAGNOSIS ; Human ; Middle Age ; Multiple Sclerosis/DIAGNOSIS ; Nuclear Magnetic Resonance/ DIAGNOSTIC USE ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - Radiology 1986 Aug;160(2):375-81 16 UI - 86256868 AU - Bucciolini M ; Ciraolo L ; Renzi R TI - Relaxation rates of paramagnetic solutions: evaluation by nuclear magnetic resonance imaging. AB - Methods for accurate calculation of nuclear magnetic resonance relaxation times are presented. Data from inversion recovery sequences with different delay times were fitted to derive T1 information on water solutions of paramagnetic ions. T2 values of the same samples were obtained by fitting signals from a multiecho sequence. According to the theory, for the field strength used (0.5 T), T1's and T2's are nearly equal and the enhancement of relaxation rates is found to be directly proportional to molar concentration. Tests performed suggest the opportunity of using the same approach in studies of tissues. MH - Biometry ; Health Physics ; Ions ; Nuclear Magnetic Resonance/*METHODS ; Solutions ; Support, Non-U.S. Gov't SO - Med Phys 1986 May-Jun;13(3):298-303 17 UI - 86256369 AU - Kurland RJ ; Ngo FQ TI - Effect of induced field inhomogeneity on transverse proton NMR relaxation in tissue water and model systems. AB - The effect of induced field inhomogeneity (IFI) on transverse NMR relaxation of water protons in tissue has been investigated by examining the field dependence of the effective transverse relaxation rates (1/T2 eff) for in vitro canine brain tissue samples. At fields of 0.47, 2.35, 7.05 T (corresponding to 20, 100, and 300 MHz, respectively) the transverse relaxation rates for both white and gray matter samples follow a field dependence of the form 1/T2 eff = C0 + C1 B0, where B0 is the applied field. The linearly dependent term, C1 B0, which reflects the IFI contribution, does not contribute much (i.e., less than 20%) at fields less than 2.0 T. However, at greater field strengths the contribution is appreciable, e.g., greater than 60% at 7.0 T. Results from model systems of glass beads are also reported to illustrate IFI effects. For both the model systems and canine brain tissue samples, the effects of restricted diffusion are qualitatively evident in Hahn spin-echo experiments. MH - Animal ; *Body Water ; Brain/ANATOMY & HISTOLOGY ; Dogs ; In Vitro ; Models, Biological ; Nerve Tissue/ANATOMY & HISTOLOGY ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/METHODS ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. SO - Magn Reson Med 1986 Jun;3(3):425-31 18 UI - 86238874 AU - Drayer B ; Burger P ; Darwin R ; Riederer S ; Herfkens R ; Johnson GA TI - MRI of brain iron. AB - A prominently decreased signal intensity in the globus pallidum, reticular substantia nigra, red nucleus, and dentate nucleus was routinely noted in 150 consecutive individuals on T2-weighted images (SE 2000/100) using a high field strength (1.5 T)MR system. This MR finding correlated closely with the decreased estimated T2 relaxation times and the sites of preferential accumulation of ferric iron using the Perls staining method on normal postmortem brains. The decreased signal intensity on T2-weighted images thus provides an accurate in vivo map of the normal distribution of brain iron. Perls stain and MR studies in normal brain also confirm an intermediate level of iron distribution in the striatum, and still lower levels in the cerebral gray and white matter. In the white matter, iron concentration is (a) absent in the most posterior portion of the internal capsule and optic radiations, (b) higher in the frontal than occipital regions, and (c) prominent in the subcortical "U: fibers, particularly in the temporal lobe. There is no iron in the brain at birth; it increases progressively with aging. Knowledge of the distribution of brain iron should assist in elucidating normal anatomic structures and in understanding neurodegenerative, demyelinating, and cerebrovascular disorders. MH - Adolescence ; Adult ; Aged ; Aging ; Brain/PATHOLOGY ; *Brain Chemistry ; Brain Diseases/METABOLISM ; Case Report ; Child ; Globus Pallidus/ ANALYSIS ; Human ; Iron/*ANALYSIS/METABOLISM ; Male ; Middle Age ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE ; Substantia Nigra/ANALYSIS SO - AJR 1986 Jul;147(1):103-10 19 UI - 86229917 AU - Hopkins AL ; Yeung HN ; Bratton CB TI - Multiple field strength in vivo T1 and T2 for cerebrospinal fluid protons. AB - To estimate the feasibility of measuring in vivo CSF protein, oxygen, or other solutes through their effect on proton relaxation times, the T1 and T2 of CSF protons has been measured within the human lateral ventricles. T1 was measured at 6.25, 25.4, and 60.1 MHz with a two-point method. T2 was measured at 6.25 and 25.4 MHz using the CPMG sequence to acquire 8 echo images. The T1 was 4.3 s with no evidence of field dependence. The T2 was 2 s. Although these values approach those for water at the same temperature it is possible that the T1 is influenced by the normal oxygen concentration. Calculations based on the relaxivity of dissolved protein indicate that the use of these methods for the detection of elevated levels of CSF protein would be less sensitive than existing methods. MH - Cerebral Ventricles/ANATOMY & HISTOLOGY ; Cerebrospinal Fluid/*ANALYSIS ; Cerebrospinal Fluid Proteins/ANALYSIS ; Human ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/METHODS SO - Magn Reson Med 1986 Apr;3(2):303-11 20 UI - 86104281 AU - Killian JA ; Borle F ; de Kruijff B ; Seelig J TI - Comparative 2H- and 31P-NMR study on the properties of palmitoyllysophosphatidylcholine in bilayers with gramicidin, cholesterol and dipalmitoylphosphatidylcholine. AB - The stoichiometric palmitoyllysophosphatidylcholine (lysoPC)/gramicidin (4:1, mol/mol) lamellar complex (Killian, J.A., De Kruijff, B., Van Echteld, C.J.A., Verkleij, A.J., Leunissen-Bijvelt, J. and De Gier, J. (1983) Biochim. Biophys. Acta 728, 141-144) is a useful model system to investigate the various aspects of lipid protein interactions. To study the effect of gramicidin on local order and motion of 1-palmitoyl-sn-glycero-3-phosphocholine (lysoPC) we employed 31P and 2H nuclear magnetic resonance (NMR) using selectively deuterated lysoPC's and we compared the results to those obtained for lysoPC in bilayers with cholesterol (1:1, mol/mol) and dipalmitoylphosphatidylcholine (DPPC) (1:4, mol/mol). 2H-NMR experiments on acyl chain deuterated lysoPC showed similar quadrupole splittings in the liquid crystalline state for the lysoPC/DPPC and the lysoPC/gramicidin samples. In the lysoPC/cholesterol sample an increase of the quadrupole splitting was found. T1 measurements showed that gramicidin decreases the lysoPC acyl chain motion, especially at the C12 position. In the lysoPC/cholesterol sample an increase of motion was observed as compared to lysoPC in fluid bilayers of DPPC. 31P-NMR and 2-H-NMR measurements of lysoPC, deuterated at the alpha- and beta-position of the choline moiety, indicated an increase in headgroup flexibility in all samples as compared to the parent compound DPPC. In addition, a change in headgroup conformation was observed. The alpha- and beta-segments in all samples exhibited concerted motion. It was found that also in the polar headgroup gramicidin induces a decrease of the rate of motion. MH - *Cholesterol ; Comparative Study ; Deuterium ; *Gramicidins ; *Lipid Bilayers ; *Lysophosphatidylcholines ; Membrane Fluidity ; Nuclear Magnetic Resonance ; Phosphorus Radioisotopes ; *Pulmonary Surfactants ; Support, Non-U.S. Gov't ; Temperature ; Thermodynamics SO - Biochim Biophys Acta 1986 Jan 16;854(1):133-42 21 UI - 86211766 AU - Cohen MD ; McGuire W ; Cory DA ; Smith JA TI - Society for Pediatric Radiology John Caffey Award. MR appearance of blood and blood products: an in vitro study. AB - There are conflicting reports on the appearance of blood and blood clot as seen in the human body by MRI. This study was designed to show the in vitro MR signal intensity of human blood products in the fresh state and to evaluate the serial MRI changes that occur over time (2 weeks). T1 relaxation times were also measured. Anticoagulated whole blood, plasma, serum, white blood cell concentrates, platelet concentrates, lysed red cells, red cell concentrates, and blood clot were studied. The results show that plasma and serum have similar T1 values, as do lysed and intact erythrocytes. T1 of serum and plasma rose initially and then fell with the aging of the samples. T1 of red blood cells, clot, and packed red blood cells decreased for the first 48 hr and then remained constant for 7 days before increasing to the initial values by 2 weeks. Platelets and white blood cells had little influence on the MR image. However, temperature had a significant effect on T1 and signal intensity. In vivo clots are complex mixtures of whole clot, lysing clot, serum, and plasma influenced in various ways by the adjacent normal or diseased tissues. The chemical and physical properties of the mixture change constantly. Because of the clot's complex nature, determining the age of a hematoma from the appearance of clots on the MR image may not be possible. MH - Adult ; *Blood ; Blood Coagulation Disorders/DIAGNOSIS ; Blood Platelets ; Blood Preservation ; Erythrocytes ; Hemorrhage/DIAGNOSIS ; Human ; In Vitro ; Leukocytes ; Methemoglobin/ANALYSIS ; Neutrophils ; *Nuclear Magnetic Resonance/DIAGNOSTIC USE ; Temperature ; Time Factors SO - AJR 1986 Jun;146(6):1293-7 22 UI - 86178436 AU - Drayer BP ; Olanow W ; Burger P ; Johnson GA ; Herfkens R ; Riederer S TI - Parkinson plus syndrome: diagnosis using high field MR imaging of brain iron. AB - The distribution of iron in the brain was analyzed using high field strength (1.5 T) magnetic resonance (MR) imaging in 14 healthy control individuals and six patients with Parkinson plus syndromes (multisystem atrophy and progressive supranuclear palsy) who were unresponsive to antiparkinsonian therapy. The normal topographic distribution of iron in the brain as indicated by high field MR images coincided precisely with the distribution of iron in the brain as determined by Perls staining for ferric iron. In Parkinson plus syndromes, there were abnormally increased concentrations of iron (decreased T2 relaxation times) in the putamen, and less prominent increases in the caudate nucleus and lateral pars compacta of the substantia nigra. In high field strength MR images of normal patients, the decreased signal intensity in the globus pallidus is more prominent than that of the putamen. In MR images of patients with Parkinson plus syndromes, the decreased signal intensity of the putamen is more prominent than that of the globus pallidus. MH - Adult ; Aged ; Atrophy ; Cerebellar Nuclei/ANALYSIS/PATHOLOGY ; Globus Pallidus/ANALYSIS/PATHOLOGY ; Human ; Iron/*ANALYSIS ; Middle Age ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE ; Parkinson Disease/*DIAGNOSIS/ PATHOLOGY ; Putamen/ANALYSIS/PATHOLOGY ; Substantia Nigra/ANALYSIS/ PATHOLOGY SO - Radiology 1986 May;159(2):493-8 23 UI - 86174243 AU - Dumoulin CL TI - Suppression of water and other noncoupled spins by homonuclear polarization transfer in magnetic resonance imaging. AB - The water component of an NMR image is suppressed by selectively detecting only those protons which are coupled to other protons. Selectivity is obtained by polarization transfer between the coupled spins. Since spin-spin coupling is independent of magnetic field strength, the suppression obtainable by polarization transfer is independent of chemical shift. Consequently, this technique does not require extremely homogeneous magnetic fields for the separation of water and lipid signals. In addition, water suppression by this technique is independent of T1 and T2. Suppression of the water signal intensity has been observed experimentally to be as high as a factor of 100. Suppression is limited only by instrumental imperfections. MH - *Body Water ; Human ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/METHODS SO - Magn Reson Med 1986 Feb;3(1):90-6 24 UI - 86167329 AU - Eisenberg AD ; Conturo TE ; Mitchell MR ; Schwartzberg MS ; Price RR ; Rich MF ; Partain CL ; James AE Jr TI - Enhancement of red blood cell proton relaxation with chromium labeling. AB - Nuclear medicine has utilized chromium (Cr) for decades to label red blood cells (RBCs). The purpose of this project was to determine whether sufficient paramagnetic Cr could be bound to red cells to influence proton relaxation significantly. We demonstrated that the T1 and T2 of RBCs can be substantially shortened by labeling them with paramagnetic Cr. Proton relaxation enhancement occurs when red cells are incubated with sodium chromate (VI) over a concentration range of 0.10 mM to 31.6 mM. Labeling with Cr at a concentration of 31.6 mM shortened the T1 of packed cells from 714 msec to 33 msec, and the T2 from 117 msec to 24 msec, as compared with nonlabeled red cells. In vitro hemolysis was significantly increased after labeling at 31.6 mM, but not at lower concentrations. Cr-induced proton relaxation enhancement varied with RBCs from different species, temperature, pH, and length of incubation. T1 values of kidneys containing labeled red cells (303 msec), or labeled cells diluted 10-fold with nonlabeled cells (479 msec), were decreased compared with kidneys containing only nonlabeled cells (600 msec). Finally, preliminary data indicate that the signal intensity of perfused renal tissue is significantly influenced in vivo by infusion of Cr-labeled RBCs. This study demonstrated that Cr labeling of RBCs sufficiently enhances red cell proton relaxation to provide excised organs containing red cells, of which 10% have been Cr-labeled, with shorter T1 and T2 values than organs containing nonlabeled cells. In addition, the ability of labeled cells to alter signal intensity in vivo suggests that Cr may have the potential to become an MRI contrast agent. MH - Animal ; Chromium Radioisotopes/*DIAGNOSTIC USE ; Erythrocytes/ *METABOLISM ; Hemolysis ; Human ; Hydrogen-Ion Concentration ; *Image Enhancement ; *Isotope Labeling ; Kidney/METABOLISM ; *Nuclear Magnetic Resonance ; Protons ; Rabbits ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. ; Temperature ; Time Factors SO - Invest Radiol 1986 Feb;21(2):137-43 25 UI - 86159704 AU - Goux WJ ; Venkatasubramanian PN TI - Metal ion binding properties of hen ovalbumin and S-ovalbumin: characterization of the metal ion binding site by 31P NMR and water proton relaxation rate enhancements. AB - In this study, water proton relaxation rate (PRR) enhancements have been used to characterize the binding of metal ions to native ovalbumin, ovalbumin in which phosphate has been enzymatically cleaved from one or both of the two protein phosphoserines, and a heat-stabilized form of the protein (S-ovalbumin). With Scatchard plots constructed from water PRR enhancements, it was found that native ovalbumin and S-ovalbumin had one strong binding site for Mn2+ ion (KD approximately equal to 6.0 X 10(-4) M). Alkaline phosphatase treated ovalbumin, a protein having a single phosphoserine, had one Mn2+ binding site of slightly weaker affinity (KD approximately equal to 8.3 X 10(-4) M), while acid phosphatase treated ovalbumin, a dephosphorylated protein, had two much weaker Mn2+ ion binding sites (KD approximately equal to 1.3 X 10(-3) M). Competitive binding studies on the native protein suggested that Zn2+ ion competes with Mn2+ for the single strong-affinity site (KD approximately equal to 6.1 X 10(-3) M) while Mg2+ and Ca2+ do not. In a second set of experiments, the paramagnetic contribution to the 31P spin-lattice (T1P) and spin-spin (T2P) relaxation times at three separate magnetic field strengths was measured. Correlation times tau c characterizing Mn2+-31P dipolar relaxation were estimated from the ratios of T1P/T2P at a single field and from the ratios of spin-lattice relaxation rates at three different field strengths. The correlation times so obtained, ranging from about 0.7 to 7.7 ns at the three field strengths, were used in calculating distances from the bound Mn2+ ion to the phosphoserines of native ovalbumin, S-ovalbumin, and alkaline phosphatase treated ovalbumins. It was determined that the phosphate of phosphoserine-68 was 5.95 +/- 0.26 and 6.29 +/- 0.18 A from the Mn2+ in the native and alkaline phosphatase treated protein, respectively, and 6.99 +/- 0.30 A away from the Mn2+ in S-ovalbumin. The phosphate of phosphoserine-344 was determined to be 5.31 +/- 0.20 and 5.75 +/- 0.10 A from the Mn2+ ion in native ovalbumin and S-ovalbumin, respectively. The 13C nucleus of [1-13C]galactose enzymatically transferred to the nonreducing end of the ovalbumin oligosaccharide chain was not found to be significantly relaxed by Mn2+ bound to the protein, even at 1:1 stoichiometric ratio of metal:protein. Using this, we estimate the nonreducing terminal of the ovalbumin oligosaccharide to be at least 39 A from the metal ion binding site on the protein. MH - Animal ; Binding Sites ; Cations, Divalent ; Chickens ; Female ; Heat ; Hydrogen-Ion Concentration ; Kinetics ; Manganese/*METABOLISM ; Mathematics ; Nuclear Magnetic Resonance/METHODS ; Ovalbumin/*METABOLISM ; Protein Binding ; Support, Non-U.S. Gov't ; Support, U.S. Gov't, P.H.S. ; Zinc/PHARMACODYNAMICS SO - Biochemistry 1986 Jan 14;25(1):84-94 26 UI - 86149418 AU - Mallard JR TI - The Wellcome Foundation lecture, 1984. Nuclear magnetic resonance imaging in medicine: medical and biological applications and problems [published erratum appears in Proc R Soc Lond [Biol] 1986 Sep 22;228(1253):527] AB - From early biological work and the first T1 nuclear magnetic resonance (n.m.r.) animal image in 1974, whole-body patient images, by using a two-dimensional Fourier transform method were achieved in Aberdeen in 1980 with a 0.04 T vertical resistive magnet. Different pulse sequences produce images dependent by different amounts on proton density, T1 and T2, and for clinical work it is advantageous to use more than one pulse sequence to image pathology. The slow improvement of spatial resolution with increasing standing magnetic field strength is discussed and information on the T1 and T2 contrast dependence is reviewed: it suggests that the gains from high fields may be less than believed hitherto. Electrocardiogram gating can be used to produce moving images of the beating heart; blood flow can be imaged and surface radiofrequency coils are used for improved detail. N.m.r. imaging has considerable potential for studying response to therapy; mental states and dementia; tissue generation; discriminating body fat and body fluids. Other nuclei such as 23Na can be imaged and the potential to image fluorine-labelled pharmaceuticals could be very exciting; n.m.r. contrast agents are now being developed. Images formed from T1 values measured for each pixel are very useful for diagnosis, but the numerical values themselves are less valuable for distinctive pathological identification. With 15 companies manufacturing n.m.r. imagers and over 200 in use in hospitals, the technique is rapidly becoming established in diagnostic clinical practice and some typical uses are presented. MH - Adenocarcinoma/DIAGNOSIS ; Animal ; Astrocytoma/DIAGNOSIS ; Brain Neoplasms/DIAGNOSIS ; Child ; Colonic Neoplasms/DIAGNOSIS ; Coronary Circulation ; Demyelinating Diseases/DIAGNOSIS ; Female ; Genital Neoplasms, Female/DIAGNOSIS ; Head and Neck Neoplasms/DIAGNOSIS ; Human ; Mice ; Neoplasms/*DIAGNOSIS ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE/ INSTRUMENTATION/METHODS ; Organ Specificity ; Pancreatic Neoplasms/ DIAGNOSIS SO - Proc R Soc Lond [Biol] 1986 Jan 22;226(1245):391-419 27 UI - 86146001 AU - Virapongse C ; Mancuso A ; Fitzsimmons J TI - Value of magnetic resonance imaging in assessing bone destruction in head and neck lesions. AB - We utilized low-field magnetic resonance imaging (MRI) to evaluate 12 patients with head and neck lesions and suspected skull base or facial bone destruction. All except one had high resolution computed tomography (CT). MRI was performed on a 0.15 tesla (low-field) resistive unit, with routinely good resolution due mainly to the use of specially designed rf receiver coils (surface coils). T1 and T2 weighted spin echo images were performed in all cases. In three instances axial, coronal, and sagittal images were done. All CTs were done with high resolution techniques on state-of-the-art equipment. Comparison of the CT and MR images (at low-field strength) showed that MRI's main strength lies in its freedom to perform images in any plane and to visualize intracranial lesions with early brain involvement. Otherwise, the two modalities are comparable. Bone destruction seen on CT was always detectable on MRI, although CT is clearly superior in resolving bone detail. MRI is recommended when direct coronal CT scans are not obtainable to evaluate superiad tumor extension. The improved visualization of nasopharyngeal soft tissue and cavernous sinus region is likely to make MRI the examination of first choice in evaluating lesions of the nasopharynx, skull base, and cavernous sinus. MH - Adult ; Aged ; *Facial Bones/RADIOGRAPHY ; Female ; Head and Neck Neoplasms/*PATHOLOGY ; Human ; Male ; Middle Age ; Nasopharyngeal Neoplasms/DIAGNOSIS/PATHOLOGY/RADIOGRAPHY ; Neoplasm Invasiveness ; Nuclear Magnetic Resonance/DIAGNOSTIC USE ; Skull Neoplasms/*DIAGNOSIS/ PATHOLOGY/RADIOGRAPHY ; Support, U.S. Gov't, P.H.S. ; Tomography, X-Ray Computed SO - Laryngoscope 1986 Mar;96(3):284-91 28 UI - 86139990 AU - Nissen MS ; Magnuson JA TI - Metal ion binding to tetrameric lima bean lectin. AB - The binding of Mn2+ and Ca2+ to tetrameric lima bean lectin has been examined by equilibrium dialysis and magnetic resonance techniques. Demetalized lectin prepared by acid treatment binds either 1 Mn2+ or 2 Ca2+/monomer. When demetalized lectin is presaturated with Ca2+, only 1 Mn2+ binds per dimer. Water proton relaxation rate enhancements and Mn2+ electron spin resonance spectra were used to monitor metal ion association processes. Following Mn2+ binding to demetalized lectin, a conformational change with activation energy of 16 kcal/mol was detected; this is similar in magnitude to that observed for a conformational change with the lectin concanavalin A. The pH dependence suggests that a histidine residue is involved. ESR spectroscopy shows clearly that 1 Mn2+ binds to each demetalized subunit, but that Ca2+ induces dissociation of half the Mn2+; this result is in agreement with the equilibrium dialysis studies. MH - Cadmium/METABOLISM ; Calcium/*METABOLISM ; Dialysis ; Electron Spin Resonance ; Hydrogen-Ion Concentration ; Lectins/*METABOLISM ; Macromolecular Systems ; Manganese/*METABOLISM ; Nickel/METABOLISM ; Nuclear Magnetic Resonance ; Support, U.S. Gov't, P.H.S. ; Temperature ; Zinc/METABOLISM SO - J Biol Chem 1986 Feb 25;261(6):2514-9 29 UI - 86112673 AU - Thomas SR ; Clark LC Jr ; Ackerman JL ; Pratt RG ; Hoffmann RE ; Busse LJ ; Kinsey RA ; Samaratunga RC TI - MR imaging of the lung using liquid perfluorocarbons. AB - Certain perfluorocarbon (PFC) compounds, commonly used as the oxygen transport components of "blood substitutes,: may be breathed as neat liquids with survival because of their chemical inertness and their high solubility for oxygen and carbon dioxide. In addition, the paramagnetism of oxygen reduces the fluorine T1 value according to an inverse relationship allowing a potential method of monitoring PO2 gradients in vivo. This article presents the results of magnetic resonance (MR) imaging of the lungs of mice and rats following breathing of four PFC liquids (FC-43, FC-75, PFOB, APF-215). The images presented were obtained at two magnetic field strengths (0.66 and 0.14 T) under conditions of breathing either ambient air or pure oxygen. Spin-lattice relaxation times (T1) for the PFCs are measured both in vitro and in vivo (in the lungs) as a function of the state of oxygenation. A MR image signal strength enhancement of up to 90% is demonstrated in vivo under conditions of pure oxygen breathing. MH - Animal ; Contrast Media/*ADMINISTRATION & DOSAGE ; Fluorocarbons/ *ADMINISTRATION & DOSAGE ; Lung/*ANATOMY & HISTOLOGY ; Mice ; Nuclear Magnetic Resonance/*DIAGNOSTIC USE ; Perfluorobutyl Tetrahydrofuran/ ADMINISTRATION & DOSAGE ; Rats ; Respiration ; Support, U.S. Gov't, Non-P.H.S. ; Support, U.S. Gov't, P.H.S. SO - J Comput Assist Tomogr 1986 Jan-Feb;10(1):1-9