Hannu Paajanen

Disc degeneration in magnetic resonance imaging : a comparative biochemical, histologic, and radiologic study in cadaver spines

Magnetic resonance imaging (MRI) findings of 89 autopsied intervertebral discs from 22 cadaveric lumbar spines were correlated with biochemical composition, conventional radiography, and histologic structure to study the nature of disc intensity changes seen in MRI. Discs with a low signal intensity on T2-weighted MRI were characterized by shortening of relaxation times, dehydration, and decreases in total proteoglycan content and chondroitin-keratan sulfate ratios in the nucleus pulposus. This corresponded well with previously published studies. In histologic structure, no obvious differences between MRI findings were found. In conclusion, a low signal intensity in a lumbar disc on T2-weighted MRI probably reflects a true biochemical disc degeneration, but its relation to structural degenerative changes is uncertain. Therefore, MRI seems to be a sensitive and a specific imaging modality for detecting pathologic biochemical disc changes in the spine of a young adult.

Magnetic Resonance Study of Disc Degeneration in Young Low-back Pain Patients

The correlation of roentgenographlc findings, clinical history, and Incipient disc degeneration (DD), diagnosed with magnetic resonance imaging, was analyzed in young patients with low-back pain (LBP). One or more lumbar discs were abnormal In 57% of the 20-year-old LBP patients (n=75) and in 35% of the asymptomatic controls (n=34) in MRI. Narrowed disc spaces and alterations attributed to lumbar Scheuermanns disease, shown on the radiographs, were always associated with DD in MRI. Such a strong relationship was not observed with transitional vertebrae, spondylolisthesis, spina bifida, or postural abnormalities. However, an Increased weight, a positive straight leg raising test, and a reduced lumbar mobility was consistent with an increase in frequency of DD. Magnetic resonance imaging is a safe and sensitive method for studying the presence and etlologic factors of DD.

Age-dependent correlation of low-back pain and lumbar disc degeneration

The prevalence of lumbar disc degeneration in subjects suffering from low-back pain (n = 207; age range 10–49 years) and in age-matched asymptomatic controls (n = 216) was investigated by magnetic resonance imaging. The percentage of subjects with degenerated discs increased with age; starting from the age of 15 years, this increase was more rapid in subjects with low-back pain. Concurrently, the number of degenerated discs was higher in the pain group than in controls. Lumbar disc degeneration manifests earlier and in a greater percentage of subjects with low-back pain than in asymptomatic controls.

Disc degeneration in young gymnasts A magnetic resonance imaging study

Magnetic resonance imaging (MRI) was performed on 35 young competitive gymnasts and 10 control subjects in order to detect the number of degenerated discs and other lumbar spinal disorders. Lumbar radiographs were obtained from all gymnasts who showed evidence of disc abnormality on MRI. Eleven gymnasts had suf fered from episodes of low back pain during exercises and eight were found to have evidence of back trauma. Only 3 of the 35 gymnasts had MRI evidence of degen erated discs associated with Scheuermanns manifes tations and spondylolysis. Lumbar radiographs con firmed the diagnosis in these three cases. The results indicate that despite the excessive range of motion and strong axial loading of the lumbar spine that are asso ciated with gymnastic maneuvers, incurable primary damage to the intervertebral discs is uncommon in young gymnasts dunng growth.

Disc degeneration in scheuermann disease

Comparison of the radiographic signs of Scheuermann disease and the corresponding disc degeneration on thoracolumbar magnetic resonance (MR) images was made in 21 young patients. Marginal sclerosis, Schmorl nodes and narrowed disc spaces, but not irregular or wedge-shaped end-plates, were significantly associated with disc degeneration. Fifty-five percent of the discs in the patients with Scheuermann disease were abnormal on MRI, compared with 10% in asymptomatic controls. Our study confirms that thoracolumbar disc degeneration is enhanced in 20-year-old patients with low back pain who have radiological evidence of Scheuermann disease.

Magnetization transfer imaging of lumbar disc degeneration. Correlation of relaxation parameters with biochemistry.

Objectives The authors attempted to find out if magnetization transfer (MT) imaging with magnetic resonance imaging (MRI) provides new information of disc degeneration. Summary of Background Data Magnetization transfer technique improves soft-tissue contrast and characterization. It measures the cross-relaxation and chemical exchange processes between free and macromolecule-bound water protons in tissues. Methods The lumbar MRI and MT of four living subjects and six cadaveric spines were performed at 0.1 T. Disc water, protein, proteoglycan, and collagen contents of cadaveric samples were correlated to MT parameters. Results The rate of magnetization transfer between free-water protons and the macromolecule-bound protons was elevated in degenerated discs. A positive correlation was found between disc collagen and total protein concentration and the rate of transfer. The contrast of normal and degenerated discs on MT images was not altered much. Conclusions More studies are needed to fully establish the importance of MT processes in the disc.

Magnetic resonance imaging findings of lumbar spine in the young: correlation with leisure time physical activity, spinal mobility, and trunk muscle strength in 15-year-old pupils with or without low-back pain

From a population of 1,503 schoolchildren, 38 15-year-old children reporting recurrent or continuous low-back pain and 38 asymptomatic controls (34 boys and 42 girls) matched for age, sex, and school class were selected for tests of spinal mobility and trunk muscle strength, and for a magnetic resonance imaging (MRI) study of the lumbar spine. In addition, the subjects were asked about leisure time physical activities in an interview preceding the measurements. Spinal muscular atrophy was the only finding that was more common among physically inactive subjects (p = 0.005). Moreover, increased occurrence of disk degeneration (DD) was observed in the low-activity group. However, the difference was not significant. Neither Scheuermann-type changes nor DD were related to spinal mobility or trunk muscle strength. Children with disk protrusion were, on the average, taller (p = 0.044), and their lumbar flexion measured by flexicurve was decreased (p = 0.043). Our results strengthen further the evidence that MRI is a sensitive measure and that imaging findings must be interpreted carefully with respect to pain and physical impairment of the lumbar spine. Furthermore, no clear evidence of the association between physical activity and early DD could be found.

The distribution of collagen types I, III, and IV in normal and malignant colorectal mucosa

OBJECTIVE To compare the distribution of interstitial collagens (type I and III) and basement membrane collagen (type IV) in cancerous and normal colon. DESIGN Retrospective study. SETTING University hospital, Finland. SUBJECTS 13 patients with colorectal cancer of different stages and grades. MAIN OUTCOME MEASURES Indirect immunofluorescence labelling for type I, III, and IV collagens of fresh frozen tissue samples, both normal and cancerous, cut into serial sections 6 microm thick. RESULTS In normal mucosa, the epithelial basement membrane showed an intense immunoreaction for type IV collagen. Type I and III collagens were localised to the interstitial stroma underlying it. The membrane in cancer samples was characterised by discontinuities and thinning as estimated by immunolabelling for type IV collagen. Furthermore, immediately adjacent to the membrane type I and III collagen positivity was fragmented. The cancerous stroma showed a strong positive immunosignal for type I and III collagens. CONCLUSION Both the epithelial basement membrane and the collagenous matrix immediately beneath it are degraded in malignant tissue. This may suggest the simultaneous activation of several degradative enzymes (as type I and III collagens are at least in part degraded by different enzymes from type IV collagen) or alterations in the expression of collagen subtypes in normal compared with malignant tissue.

Disc degeneration and lumbar instability. Magnetic resonance examination of 16 patients.

Flexion and extension radiographs of 75 young males with low back pain disclosed abnormal segmental motion of the lumbar spine in 16 patients with translational movements in 20 intervertebral segments. These 16 patients were further investigated by magnetic resonance imaging to assess disc degeneration in the unstable segments. On T2-weighted images of the 20 segments, the disc was normal in 13 and degenerated in only 7 patients. Thus, the initial factor in lumbar instability in young patients with low back pain is not always degeneration of the disc.

Modification of platelet aggregation and thromboxane synthesis by intravascular contrast media.

Radiographic contrast media (RCM) decreased significantly platelet aggregation in human platelet-rich plasma (PRP) after addition of arachidonic acid (AA) or adenosine diphosphate (ADP). Unlike hypertonic saline, diatrizoate, ioxaglate, and iopamidol (40 and 160 mM) inhibited AA-induced aggregation. One hundred sixty mM ioxaglate inhibited slightly the concomitant formation of immunoreactive thromboxane B2 (TXB2). The ionic RCM ioxaglate (40 and 160 mM) and diatrizoate (160 mM), but not the nonionic iopamidol, decreased the ADP-induced aggregation more than hypertonic saline. When PRP was incubated with different RCM without any aggregating agents or with ADP, the formation of TXB2 was negligible. Results of this study show that inhibition of AA- and ADP-induced platelet aggregation by RCM is partly due to hypertonicity and partly related to the chemical structure of the RCM molecule. The inhibition of AA-induced aggregation is not caused by the lack of formation of aggregatory TXA2.