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PubMed1997

Fast spin-echo and fast fluid-attenuated inversion-recovery versus conventional spin-echo sequences for MR quantification of multiple sclerosis lesions.

PURPOSE: To compare fast spin-echo (FSE) and fast fluid-attenuated inversion recovery (FLAIR) sequences with conventional spin-echo (CSE) MR imaging in the quantification of the number and volume of multiple sclerosis lesions. METHODS: In 30 patients with relapsing-remitting multiple sclerosis, we calculated the total number and volume of lesions detected with each of the three sequences using a semiautomated program. RESULTS: On CSE sequences, we calculated a total of 2,583 lesions with a global volume of 836.3 cm3. With FSE sequences, we observed a 16% relative reduction in the number of lesions detected and a 25% relative reduction in global volume as compared with CSE. With fast FLAIR sequences, we detected a significantly lower number and volume of infratentorial lesions, whereas at the cortical/subcortical level the lesions were both more numerous and bulkier than on CSE sequences. Finally, we observed a higher lesion/white matter contrast, a significant reduction in time required for the quantification of lesion load, and a very low interobserver variability in favor of fast FLAIR sequences. CONCLUSION: Despite its limitations in the detection of infratentorial lesions, the fast FLAIR sequence in conjunction with a semiautomated quantification program provides a reliable means to evaluate the total lesion burden in patients with MS.

Adult↗
PubMed2006

Nigral degeneration and striatal dopaminergic dysfunction in idiopathic and Parkin-linked Parkinson's disease.

We have used MR segmented inversion recovery ratio imaging (SIRRIM) of the substantia nigra pars compacta to detect and correlate nigral signal change in idiopathic Parkinson's disease (PD) and parkin patients with striatal (18)F-dopa uptake. Nine PD patients, nine parkin patients, and eight control subjects were studied with a combination of MR inversion recovery sequences sensitive to nigral cell loss. Blinded independent observer rating and quantified nigral signal analysis were performed on all subjects. Striatal regions of interest were defined on T(1)-weighted MRI co-registered to (18)F-dopa positron emission tomography. On blinded observer rating of the SIRRIM dorsal and ventral nigral images, 25% (2/8) of control subjects, 44% (4/9) of PD patients, and 67% (6/9) of parkin patients were classified as abnormal. Quantified total nigral signal intensities were reduced to a greater extent in the parkin compared to PD patients. There was a greater predilection for signal reduction in the ventral nigral slice of the PD compared to the parkin patient group, who showed a more uniform involvement. All PD and parkin patients were discriminated from controls on the basis of caudate and putamen (18)F-dopa Ki reductions. Our results suggest that MR segmented inversion recovery ratio imaging shows poor sensitivity for discriminating parkin and idiopathic PD patients from normal controls. Where nigral signal abnormalities were seen, parkin patients manifested generalized nigral cell loss with widespread striatal dopamine terminal dysfunction compared with the lateral nigral targeting seen in PD and selective loss of putamen (18)F-dopa uptake.

Adult↗
PubMed1988

Alterations in the binding site of the cyclic AMP receptor protein at the Escherichia coli galactose operon regulatory region.

Gene manipulation techniques have been used to alter the binding site for the cyclic AMP-cyclic AMP receptor protein complex (cAMP-CRP) at the regulatory region of the Escherichia coli galactose (gal) operon. The effects of these changes on CRP-dependent stimulation of expression from the galP1 promoter in vivo have been measured, and gel binding assays have been used to measure the affinity of cAMP-CRP for the modified sites. Firstly we have deleted progressively longer sequences from upstream of the gal CRP site in order to locate the functional limit of the site. A deletion to -49, removing the first base that corresponds to the consensus sequence for a CRP binding site, is sufficient to reduce CRP binding and block CRP-dependent stimulation of P1. Secondly, we used synthetic oligonucleotides to invert the asymmetric nucleotide sequence at the gal CRP binding site or to make the sequence symmetric. Inversion of the site has little effect on CRP binding, the architecture of open complexes at P1 revealed by DNAase I footprinting, or the stimulation of transcription from P1. Making the site symmetric increases the affinity for CRP by over 50-fold and leads to increased transcription from P1, whilst hardly altering the DNAase I footprint of open complexes. Our results confirm that the strength of binding of CRP depends on the nature of the site and show that it is this that principally accounts for differences in CRP-dependent stimulation of transcription.

Base Sequence↗
PubMed1994

The rates and patterns of deletions in the human factor IX gene.

Deletions are commonly observed in genes with either segments of highly homologous sequences or excessive gene length. However, in the factor IX gene and in most genes, deletions (of > or = 21 bp) are uncommon. We have analyzed DNA from 290 families with hemophilia B (203 independent mutations) and have found 12 deletions > 20 bp. Eleven of these are > 2 kb (range > 3-163 kb), and one is 1.1 kb. The junctions of the four deletions that are completely contained within the factor IX gene have been determined. A novel mutation occurred in patient HB128: the data suggest that a 26.8-kb deletion occurred between two segments of alternating purines and pyrimidines and that a 2.3-kb sense strand segment derived from the deleted region was inserted. For our sample of 203 independent mutations, we estimate the "baseline" rates of deletional mutation per base pair per generation as a function of size. The rate for large (> 2 kb) deletions is exceedingly low. For every mutational event in which a given base is at the junction of a large deletion, there are an estimated 58 microdeletions (< 20 bp) and 985 single-base substitutions at that base. Analysis of the nine reported deletion junctions in the factor IX gene literature reveals that (i) five are associated with inversions, orphan sequences, or sense strand insertions; (ii) four are simple deletions that display an excess of short direct repeats at their junctions; (iii) there is no dramatic clustering of junctions within the gene; and (iv) with the exception of alternating purines and pyrimidines, deletion junctions are not preferentially associated with repetitive DNA.

Base Sequence↗
PubMed1991

Nucleotide sequence and coding capacity of the large (L) genomic RNA segment of Seoul 80-39 virus, a member of the hantavirus genus.

The nucleotide sequence of the large (L) genomic RNA segment of Seoul 80-39 virus was determined from overlapping cDNA clones. The virion L RNA segment is 6530 nucleotides long. The 3' and 5' terminal sequences are inversely complementary for 15 bases. The viral complementary-sense RNA contains a single open reading frame from an AUG codon at nucleotide position 37-39 to a UAA stop codon at nucleotide position 6490-6492. This ORF could encode a polypeptide of 2151 amino acids (246,662 kDa) which likely corresponds to the L protein detected in purified viral particles (Elliott et al., 1984) and is assumed to be an RNA-dependent RNA polymerase molecule (Schmaljohn and Dalrymple, 1983). Comparison of the L protein of the Seoul 80-39 virus with the polymerase proteins encoded by other negative-stranded RNA viruses revealed 44% similarity only with the part of the Bunyamwera virus L protein (Elliott, 1989) and a very weak homology with the PB1 protein of influenza virus.

Amino Acid Sequence↗
PubMed1994

Effects of the introduction of L-nucleotides into DNA. Solution structure of the heterochiral duplex d(G-C-G-(L)T-G-C-G).d(C-G-C-A-C-G-C) studied by NMR spectroscopy.

The effect of the substitution of a L-nucleoside for a D-nucleoside in the duplex d(G-C-G-T-G-C-G).d(C-G-C-A-C-G-C) was studied by UV and NMR spectroscopy. These unnatural oligonucleotides have potential for antisense DNA technology [Damha, M. J., Giannaris, P. A., & Marfey, P. (1994) Biochemistry (preceding paper in this issue)]. The thermal stability of such duplexes is lower than that of the natural one and is dependent on the nucleotide type and/or sequence. Interestingly, inversion of the chirality of thymidine but not adenosine coincides with a large stabilizing enthalpy change. The structure of the heterochiral duplex d(G1-C2-G3-(L)T4-G5-C6-G7).d(C8-G9-C10-A11-C12-G13- C14), where (L)T denotes the mirror image of the natural thymidine, has been determined by NMR spectroscopy. The sugar conformation was determined using the sum of coupling constants and the distances using a model free relaxation matrix approach. The torsion angles of the backbone follow from 3JHH, 3JHP, and 4JHP coupling constants. The structure of the duplex was calculated by metric matrix distance geometry followed by simulated annealing. The structure is close to that of B-DNA. The base pair formed by (L)T and A is of the Watson-Crick type. All sugars adopt an S-type pucker. The incorporation of the L-sugar in the duplex is accomplished by changes in the backbone torsion angles around the phosphates and the glycosidic torsion angle of (L)T. The modification induces changes in the natural strand as well. The structure exhibits an unusual interaction between the aromatic rings of the (L)T4.A11 and G3.C12 base pairs, which provides a plausible explanation of the unusual thermodynamic properties of the duplex.

Base Sequence↗
PubMed1980

Analysis of the nucleotide sequence of an invertible controlling element.

The nucleotide sequence of the inversion region responsible for flagellar phase variation in Salmonella was determined. The inversion region is 995 base pairs (bp) in length and is bounded by a 14-bp inverted repeat sequence. A homologous recombination event between the 14-bp inverted repeat sequences would result in the inversion of the DNA segment between them. Sequence homologies with other systems suggest that the 14-bp inverted repeat sequences may have some general significance as sites for specific recombinational events. The gene which specifies H2 flagellin synthesis begins 16 bp outsie the inversion region. Within the inversion region, an open translational frame exists which could encode a low molecualr weight polypeptide (190 amino acids).

Amino Acid Sequence↗
PubMed1997

Localized proton magnetic resonance spectroscopy in patients with adult adrenoleukodystrophy. Increase of choline compounds in normal appearing white matter.

OBJECTIVES: To describe the changes in the results of magnetic resonance imaging and spectroscopy occurring in the normal-appearing white matter of patients with adult adrenoleukodystrophy and to present evidence of a particular change that may serve as a marker for the follow-up of the disease. DESIGN: Neurologic, magnetic resonance imaging, and localized proton spectroscopic examinations were performed in 11 patients with adult adrenoleukodystrophy and compared with 11 sex- and age-matched controls. PATIENTS: Eleven patients with adult adrenoleukodystrophy participated in a trial of dietary therapy with glyceryl trioleate and glyceryl trierucate (Lorenzo's oil) in the Fédération de Neurologie and the Institut National de la Santé et de la Recherche Médicale, Unité 134, at the Hôpital de la Salpêtrière in Paris, France. RESULTS: The results of magnetic resonance imaging of the white matter were normal in 2 patients and showed areas of mild symmetrical hypersignals on T2-weighted images and fluid attenuated inversion recovery sequences, localized in the posterior white matter in 9 patients. The results of spectroscopy indicated that the peak of the area of choline-containing compounds was increased at long echo times in patients with adult adrenoleukodystrophy, which may reflect very long-chain fatty acid accumulation in this disease. The peak of the area of myo-inositol-containing compounds was increased at short echo times in patients with adult adrenoleukodystrophy, which may indicate a rise in this metabolite concentration. The N-acetylaspartate-creatine amplitude ratio was significantly decreased in patients with motor deficit. The significance of this finding remains to be established. CONCLUSIONS: The results of localized proton magnetic resonance spectroscopy show abnormalities in the cerebral white matter of patients with adult adrenoleukodystrophy, which may contribute to the understanding of the pathophysiologic characteristics of the disease. Although changes in the results of spectroscopy found in this disease are not specific, the increase of choline-containing compounds may reflect the accumulation of very long-chain fatty acids in the central nervous system. Localized proton magnetic resonance spectroscopy may prove a valuable technique, in addition to magnetic resonance imaging, for noninvasive investigation of patients with adult adrenoleukodystrophy undergoing future clinical trials.

Adrenoleukodystrophy↗
PubMed1999

Transfer insensitive labeling technique (TILT): application to multislice functional perfusion imaging.

Cerebral blood flow can be studied in a multislice mode with a recently proposed perfusion sequence using inversion of water spins as an endogenous tracer without magnetization transfer artifacts. The magnetization transfer insensitive labeling technique (TILT) has been used for mapping blood flow changes at a microvascular level under motor activation in a multislice mode. In TILT, perfusion mapping is achieved by subtraction of a perfusion-sensitized image from a control image. Perfusion weighting is accomplished by proximal blood labeling using two 90 degrees radiofrequency excitation pulses. For control preparation the labeling pulses are modified such that they have no net effect on blood water magnetization. The percentage of blood flow change, as well as its spatial extent, has been studied in single and multislice modes with varying delays between labeling and imaging. The average perfusion signal change due to activation was 36.9 +/- 9.1% in the single-slice experiments and 38.1 +/- 7.9% in the multislice experiments. The volume of activated brain areas amounted to 1.51 +/- 0.95 cm3 in the contralateral primary motor (M1) area, 0.90 +/- 0.72 cc in the ipsilateral M1 area, 1.27 +/- 0.39 cm3 in the contralateral and 1.42 +/- 0.75 cm3 in the ipsilateral premotor areas, and 0.71 +/- 0.19 cm3 in the supplementary motor area.

Artifacts↗
PubMed2001

Loss of subtelomeric sequence associated with a terminal inversion duplication of the short arm of chromosome 4.

We report on a 4(1/2)-year-old girl, who presented with multiple minor anomalies consistent with trisomy for 4p. GTG-banding identified a de novo terminal inversion duplication of distal 4p, dup(4)(p16.3p15.3). Fluorescence in situ hybridization (FISH) with a wcp4 probe confirmed the chromosome 4 origin of the additional material. FISH with a 4p subtelomere probe, D4F26, showed no signal on the dup(4) chromosome identifying a deletion of this region. Molecular analysis of 4p STS loci confirmed the subtelomeric deletion and showed loss of the paternal allele in this region. The paternal origin of the deleted region and homozygosity for one of the two paternal alleles within the region of the duplication suggests that a sister chromatid rearrangement on the paternal chromosome 4 was involved in the formation of the dup(4) chromosome. To date, the best characterized mechanisms of formation of chromosome duplications are terminal inversion duplications of 8p, which were shown to be derived from rearrangements at maternal meiosis-I. Our data show that mechanisms other than a maternal meiosis-I rearrangement can lead to the formation of terminal inversion duplications. FISH analysis with the appropriate subtelomeric probes is warranted in terminal inversion duplications to check for associated deletions.

Child, Preschool↗
PubMed2000

Correlation between quantitative EMG and muscle MRI in patients with axonal neuropathy.

The aim of the study was to investigate whether there are correlations between electromyography (EMG) data and findings in muscle magnetic resonance imaging (MRI). Quantitative EMG data and the amount of pathologic spontaneous activity (PSA) were compared with MRI signal intensities of the tibialis anterior muscles of 20 patients with axonal polyneuropathy and 14 healthy subjects. Using hierarchical regression analysis, the mean motor unit action potential (MUAP) size index (SI) and the amount of PSA were accurate predictors of T1-weighted signal intensity in MRI, an expression of fatty degeneration. The MUAP SI was superior to MUAP amplitude in explaining the variance of T1 signal intensity. Age was not a relevant factor. A high correlation was found between the amount of PSA and the T2-weighted signal intensity in short tau inversion recovery sequence. Magnetic resonance imaging demonstrates the structural changes and thus visualizes the outcome of the functional changes of denervation and reinnervation detected by EMG.

Action Potentials↗
PubMed2003

Rheumatoid arthritis of the shoulder joint: comparison of conventional radiography, ultrasound, and dynamic contrast-enhanced magnetic resonance imaging.

OBJECTIVE: To determine the role of ultrasound and magnetic resonance imaging (MRI) compared with conventional radiography in the detection of chronic and acute inflammatory manifestations of rheumatoid arthritis (RA) of the shoulder joint. METHODS: Forty-three consecutive patients with known RA prospectively underwent clinical examination, radiography, ultrasound, and MRI of the shoulder joints. Each patient was assigned a clinical/laboratory score consisting of 7 parameters, including measurements of shoulder mobility, the erythrocyte sedimentation rate, and C-reactive protein level. Conventional radiography was standardized and performed in 2 planes. Ultrasound was performed in 10 predefined planes using a 7.5-MHz linear transducer. MRI at 1.5T comprised transverse and oblique coronal T1- and T2*-weighted fast spin-echo, gradient-echo (GRE), and inversion-recovery sequences with a matrix size of up to 512 pixels. A dynamic T1-weighted GRE sequence was acquired with intravenous administration of contrast medium. Erosions were assessed using all 3 imaging techniques on a 4-point scale. Soft-tissue involvement was evaluated according to the presence of synovitis, tenosynovitis, and bursitis on ultrasound and MRI. The results in the study group were compared with those obtained in a control group of 10 patients with shoulder pain. RESULTS: In the study group, erosions of the humeroscapular joint were detected by conventional radiography in 26 patients, by ultrasound in 30 patients, and by MRI in 39 patients; the differences were statistically significant for the comparisons of conventional radiography with MRI and for ultrasound versus MRI (P < 0.0001). Conventional radiography detected 12 erosions of the scapula and MRI detected 15. Synovitis was demonstrated in 12 patients by ultrasound and in 27 patients by MRI (P = 0.0003). Tenosynovitis was observed in 15 patients by ultrasound and in 28 patients by MRI (P = 0.0064). Bursitis was detected in 13 patients by ultrasound and in 18 patients by MRI. The findings on dynamic contrast-enhanced MRI correlated significantly with the detection of synovitis by ultrasound and erosions by static MRI (P < 0.05). CONCLUSION: Ultrasound and MRI supplement conventional radiography in assessing the shoulder joint. Although conventional radiography can be used as the sole method of following up known joint destruction in RA, ultrasound and, preferably, MRI are recommended as additional techniques in the initial diagnostic evaluation when radiography yields negative results.

Adult↗
PubMed2004

Diagnostic value of magnetic resonance imaging of the forefeet in early rheumatoid arthritis when findings on imaging of the metacarpophalangeal joints of the hands remain normal.

OBJECTIVE: To investigate the diagnostic role of magnetic resonance imaging (MRI) of the forefeet in patients with early rheumatoid arthritis (RA) in whom findings on MR images of the hands are normal and conventional radiographs of the hands and feet do not show erosions. METHODS: The study group comprised 25 patients with early RA (disease duration of <12 months) in whom erosions were not demonstrated on conventional radiographs of the hands and feet. These patients underwent MRI of the clinically dominant hand to detect signs of arthritis. If results of MRI of the hand were normal according to the Outcome Measures in Rheumatology Clinical Trials (OMERACT) RA-MRI scoring system (RAMRIS), MRI of the dominant forefoot was performed. The MRI protocol comprised coronal and sagittal T1-weighted spin-echo (before and after administration of contrast medium), coronal fat-suppressed short tau inversion recovery sequences, coronal and sagittal T2-weighted turbo spin-echo sequences, and axial fat-suppressed T1-weighted spin-echo sequences after administration of contrast medium. MRI of the forefeet was analyzed on the basis of a modified RAMRIS. RESULTS: MRI revealed pathologic findings in the hands of 15 of 25 patients (edema in 9 patients, synovitis in 12, erosions in 6, defects in 3). In 10 patients with a mean disease duration of 9.4 weeks, hand MRI scans were normal according to RAMRIS. Four of these 10 patients had tenosynovitis of the finger flexor tendons (there was no OMERACT criterion for tenosynovitis). RAMRIS analysis of the corresponding MRI scans of the forefeet of these patients revealed signs of edema in 7 patients, synovitis in all 10 patients (at the third metatarsophalangeal [MTP] joint in 7, at the fourth MTP joint in 6, at the first MTP joint in 4, and at the fifth MTP joint in 2 patients), tenosynovitis of the foot flexor tendons in 2 patients, erosions at the second and third MTP joints in 1 patient, and a single defect at the first MTP joint in 1 patient. CONCLUSION: RAMRIS analysis of MRI scans of the forefeet detected synovitis and bone edema in patients with early RA in whom MRI of the finger joints was normal. MRI of the forefeet contributes an additional tool aimed at earlier and more accurate diagnosis and thus might allow an earlier decision to start appropriate medication in patients with early RA.

Adult↗
PubMed1993

Effects of 45-Hz magnetic fields on the functional state of the human brain.

The influence of sinusoidal 45-Hz magnetic fields on the brain functions of 20 volunteers was investigated in a double-blind study using spectral analysis of EEG and measurements of Omega potentials and reaction time (RT). The field strength was 1,000 A/m (1.26 mT) and the duration of exposure was 1 h. Ten volunteers were exposed to a continuous field and ten received an intermittent exposure (1 s on/l s off). Each person received one real and one sham exposure. One half of the volunteers got the real exposure first and the sham treatment after at least 24 h. For the rest, the sequence was inverse. The measurements of EEG, omega potentials and RT were performed before and after each exposure. Several statistically significant changes were observed, most of them after intermittent exposure. In the EEG, an increase of alpha (7.6-13.9 Hz) activity and a decrease of delta (1.5-3.9 Hz) activity were observed. Beta waves (14.2-20 Hz) increased in the frontal derivations as did the total power in occipital derivations. The mean and peak frequencies of EEG increased mainly in the frontal derivations. No direct effects on RT were seen. Learning to perform the RT test (decrease of RT in repeated trials), however, seemed to be affected by the exposure. The persons who received real exposure first learned more slowly than those who got sham exposure first. Further experiments are necessary to confirm the findings and for understanding the mechanisms of the effects.

Adult↗
PubMed2002

Magnetic resonance imaging as a supplement for the clinical staging system of Durie and Salmon?

BACKGROUND: This study evaluated the prognostic value of a three-grade staging system of spinal involvement using magnetic resonance imaging (MRI) in patients with multiple myeloma and determined its usefulness as an independent parameter in the staging system of Durie and Salmon. METHODS: Seventy-seven previously untreated patients with multiple myeloma underwent MRI of the thoracic and lumbar spine with unenhanced T1-weighted spin echo and short-tau inversion time inversion recovery sequences. The patients were evaluated according to their infiltration patterns and the extent of bone marrow involvement was staged using a three-grade scale: Stage I, no focal or diffuse infiltration; Stage II, 1-10 foci or mild diffuse infiltration; Stage III, more than 10 foci or strong diffuse infiltration. RESULTS: The infiltration patterns had no significant effect on survival. Of 77 patients, 25 would have been understaged using the standard staging system of Durie and Salmon without the findings of MRI and 8 patients would have been understaged if the staging was based only on MRI. The combination of the staging system of Durie and Salmon and MRI was highly significant with respect to survival (P < 0.0001, log rank analysis). MRI staging I-III was independent of the staging system of Durie and Salmon (Cox regression model). CONCLUSIONS: A three-grade staging of spinal MRI provides a significant prognostic tool for patients with multiple myeloma. The authors propose including it in the staging system of Durie and Salmon.

Aged↗
PubMed2002

Effect of IL-1beta-induced macromolecular depletion on residual quadrupolar interaction in articular cartilage.

PURPOSE: Sodium multiple-quantum filtered (MQF) NMR spectroscopy may potentially be used to measure proteoglycan (PG) depletion in cartilage caused by osteoarthritis (OA). The purpose of this work was to quantify the effect of interleukin-1 (IL-1beta)-induced macromolecule depletion on the residual quadrupolar interaction (RQI) of sodium in bovine cartilage plugs. MATERIALS AND METHODS: Fifteen 8-mm-diameter cartilage plug specimens were cored from the articular surface of fresh bovine patellae. All plugs were kept in culture media and nine of the plugs were subjected to interleukin-1 (IL-1beta)-induced degeneration of cartilage for 4, 6, and 7 days. Sodium NMR spectra were obtained from each sample with a 1-cm-diameter solenoid coil in a 2T whole-body magnet interfaced to a custom-built spectrometer. We employed a previously described theoretical model to analyze triple-quantum filtered (TQF) and double-quantum filtered magic angle (DQFMA) spectra obtained from normal cartilage and cartilage treated with IL-1beta. The model assumes a static Gaussian distribution of the RQI frequency, omega(Q), in the sample. TQF and DQFMA spectra from each sample were fitted with the appropriate signal expressions to determine sigma (the root mean square (RMS) omegaQ), T2f, and T2s. An inversion-recovery sequence was used to determine T1 of each plug. A spectrophotometric assay was used to determine the amount of PG depleted from each plug. Histology was performed to visualize the PG loss in cartilage plugs. We defined sigma as the measure of changes in macroscopic order in the tissue. RESULTS: Simulated spectra from the theoretical model were in excellent agreement with the experimental data. We were able to determine the relaxation times as well as sigma of each specimen from their corresponding fits. T2f ranged between 2.26-3.50 msec, decreasing with increased PG loss. Over the range of PG depletion investigated, T2s increased from 12.3 msec to 14.9 msec, and T1 increased from 16 msec to 21 msec, while sigma decreased from 180 Hz to 120 Hz. The order of macromolecules in the cartilage tissue decreased substantially with PG loss. Histology sections clearly showed qualitative visualization of the PG loss in cartilage following treatment with IL-1beta. CONCLUSION: We demonstrated that IL-beta-induced macromolecule depletion in cartilage not only changes the relaxation characteristics of sodium but also changes RQI of the tissue. Using MQF sodium spectroscopy we quantified the changes in sigma and showed that loss of macromolecules reduces the degree of order in the tissue.

Animals↗
PubMedDate not supplied

MR imaging of muscle and tender points in fibromyalgia.

Fibromyalgia is a syndrome manifested by chronic, diffuse musculoskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1-weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1-weighted, gadopentetate dimeglumine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibromyalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.

Adult↗
PubMedDate not supplied

Measurement of renal transit of gadopentetate dimeglumine with echo-planar MR imaging.

Times of peak gadolinium concentration ([Gd]) after intravenous (IV) and left ventricular (LV) bolus injection of gadopentetate dimeglumine were determined in renal cortex and medulla in normal rabbits and in rabbits after saline load (overhydration) or hemorrhage (dehydration). Magnetic resonance images were obtained with echo-planar inversion-recovery sequences, and signal intensity-versus-time curves in cortical and medullary regions of interest were converted to [Gd]-versus-time curves. Cortical perfusion measured with microspheres demonstrated that the three physiologic states were significantly different. There were three separate [Gd] peaks in both the cortex and medulla as the bolus moved from one anatomic compartment to the next. The first cortical peak occurred sooner after LV than after IV bolus injection (P < .05) and later in dehydrated than in normal and overhydrated rabbits (P < .05). The first medullary peak always followed the first cortical peak by about 6-10 seconds and mirrored the cortical patterns. The second and third cortical peaks were consistent with proximal and distal tubular transit. These peaks similarly showed faster response to LV than IV injection and were delayed by hemorrhage. The authors conclude that quantitative physiologic information can be obtained with dynamic contrast-enhanced MR imaging of the kidney.

Animals↗