Kinematic magnetic resonance imaging of the upper cervical spine using a novel positioning device.

STUDY DESIGN: The development of a novel positioning device for magnetic resonance imaging of the upper cervical spine and an evaluation of motion patterns of the craniovertebral junction in asymptomatic volunteers as a part of the whole cervical spine motion. OBJECTIVES: To design and construct a positioning device that enables magnetic resonance imaging of the cervical spine in rotation, lateral bending, flexion, and extension in a horizontally open magnetic resonance scanner, and to define reference values for movements of the occiput (C0), the atlas (C1), and the axis (C2) in asymptomatic volunteers. SUMMARY OF BACKGROUND DATA: In previously used devices, the direction of motion is limited usually to flexion-extension, or the position of the head and neck are adjusted without a positioning device using semihard wedges or pillows. METHODS: Magnetic resonance imaging of the upper cervical spine in 20 asymptomatic individuals (10 men and 10 women) was performed in a horizontally open 0.23-T magnetic resonance imager in progressive steps during rotation, lateral bending, and flexion-extension using axial, coronal, and sagittal imaging planes, respectively. The positions of C0, C1, and C2 were measured, and pattern of motions between segments analyzed. Lateral displacement of the atlas during lateral bending and cranial migration distance during flexion-extension were assessed. RESULTS: The nonferromagnetic positioning device was designed and constructed. The motion patterns of the craniovertebral junction during rotation did not differ between the men and women, but in lateral bending there was a small difference between genders at C1-C2. In men, the position of C1 during flexion-extension was consistently more extended in relation to C0 and C2 than in women. CONCLUSIONS: The new positioning device allows magnetic resonance imaging of the upper cervical spine during flexion, extension, rotation, and lateral bending. To assess the relationship between C0-C1 and C1-C2 in flexion and extension, separate reference values for men and women are recommended.

Recurrent low back pain and early disc degeneration in the young.

STUDY DESIGN: A prospective 9-year follow-up study involving randomized matched subgroups of 15-year-old schoolchildren with or without low back pain at baseline. OBJECTIVES: To evaluate the long-term persistence of initially reported recurrent low back pain, and to examine the significance of abnormalities found in magnetic resonance imaging of lumbar discs in individuals 15 and 18 years of age as possible contributors to persistently recurrent low back pain. SUMMARY OF BACKGROUND DATA: In surveys among children and teenagers during the past few years, as many as half of all children in a community report a history of low back pain. The current results, in accordance with previous findings, indicate that there is a subgroup of adolescents with more chronic symptoms which, in the authors' opinion, deserves more attention. Disc disease accompanying low back pain is a key issue both in research and clinical practice. The significance of early degenerative findings in the lumbar discs is not known. METHODS: In the survey of 14-year-olds (n = 1503), a subgroup (7.8%) with recurrent low back pain was found. A random sample of individuals with recurrent low back pain (n = 40) and an equal number of completely asymptomatic control subjects were selected for a comparative study. The selected groups were examined by magnetic resonance imaging at 15 and 18 years of age. The participation rate of youth at 14, 18, and 23 years of age for all three questionnaires was 82% (29 boys and 33 girls). Imaging data were interpreted by two blinded radiologists experienced in low-field-strength magnetic resonance imaging. In calculations of relative risks, the participants reporting recurrent low back pain in all phases of the study were compared with participants who had no persistently recurrent pain. RESULTS: Eleven participants (35%) in the original group with low back pain persistently reported recurrent pain. In 15-year-old participants with disc degeneration, the relative risk of reporting recurrent low back pain up to the age of 23 years was 16 (95% confidence interval 2.2-118) compared with those having no disc degeneration. In addition, disc protrusion and Scheuermann-type changes at 15 years contributed to the risk of persistently recurrent low back pain. CONCLUSIONS: The authors' earlier findings already favored the hypothesis of a causal relation between the early evolution of a degenerative process of lower lumbar discs and recurrent low back pain in the near future. The current results further strengthen this hypothesis, indicating that individuals with disc degeneration soon after the phase of rapid physical growth not only have an increased risk of recurrent low back pain at this age, but also a long-term risk of recurrent pain up to early adulthood.

Orthopedic and interventional applications at low field MRI with horizontally open configuration. A review.

The recently introduced horizontally open configuration imagers allow imaging of knee, hip or shoulder during whole range of motion, which is not possible in conventional MR imagers. Special joint motion devices can be used to provide accurate and reproducible studies. In cervical spine, functional MR imaging may be useful in evaluating alarligament stability in patients with late sequelae of a whiplash injury, and in patients with rheumatoid arthritis who are clinically suspected of having a cervical myelopathy or superior migration of the odontoid process. In shoulder, full range of motion abduction study may be helpful in assessing the supraspinatus tendon impingement. To evaluate patellofemoral malalignment, quadriceps loading is recommended since associated contracting muscles and related soft tissue structures can be evaluated. The position of the femoral head relative to the acetabulum during different positions can be assessed. Open-configuration scanners provide an access to patients during scanning procedure, and therefore permit interventional procedures to be monitored with MRI. Such interventions include aspiration cytology/biopsy and different drainage procedures.

Development of degenerative changes in the lumbar intervertebral disk: results of a prospective MR imaging study in adolescents with and without low-back pain.

PURPOSE: To investigate the frequency, pattern, and sequence of early degenerative changes in the lumbar spine. MATERIALS AND METHODS: On the basis of a survey of 1,503 14-year-old schoolchildren, a randomized sample of 40 subjects with low-back pain (LBP) and 40 asymptomatic subjects were invited to undergo magnetic resonance (MR) imaging of the lumbar spine at 15 and at 18 years of age. Altogether, 62 subjects participated in both studies. RESULTS: The frequency of disk degeneration at follow-up was greater in the patients with LBP (increased from 42% to 58%) than among the asymptomatic subjects (from 19% to 26%) (P = .01). No such difference was found with disk protrusion, although disk protrusion was seen only in subjects with LBP at baseline examination (19%). CONCLUSION: Degenerative changes emerge rapidly after the adolescent growth spurt. The MR imaging appearance of the degenerative processes is similar regardless of symptoms, although these processes are more common in symptomatic adolescents and develop at an earlier age. There appears to be a positive correlation between degenerative lumbar disk disease and LBP in adolescence.

Magnetization transfer magnetic resonance imaging of parenchymal lung disease.

RATIONALE AND OBJECTIVES: Magnetic resonance imaging with magnetization transfer (MT) contrast recently has been described as a method that may provide additional information about the macromolecular composition of tissue. Magnetization transfer contrast images were compared to conventional gradient-recalled echo images in a variety of pulmonary parenchymal diseases and normal lung. METHODS: Single-slice gradient echo images were obtained with and without an off-resonance radio frequency pulse on a 0.1T MR scanner. The change in signal intensity between identical regions of interest on non-MT and MT images was determined in 13 patients with known lung disease, five healthy volunteers, and three postmortem atelectatic dog lungs. RESULTS: No significant change in signal intensity (MT effect) was observed in fat, flowing blood, normal lung, atelectatic lung, or in acute pulmonary edema. Chronic parenchymal lung disease showed the greatest MT effect, 37.7% +/- 7.5. Acute infectious lung disease showed an intermediate degree of MT effect, 19.5% +/- 3.0. CONCLUSIONS: Magnetization transfer contrast magnetic resonance imaging of pulmonary disease is feasible at low field strength and may be useful in the characterization and differentiation of pulmonary parenchymal abnormalities. Magnetization transfer contrast appears to be proportional to the amount of interstitial fibrosis in lung parenchyma, while acute inflammatory cell infiltration exhibits less MT effect and acute pulmonary edema exhibits very little.

Age-related MRI changes at 0.1 T in cervical discs in asymptomatic subjects.

The age-dependent occurrence of cervical degenerative changes was studied using 0.1 T MRI in 89 asymptomatic volunteers aged 9 to 63 years. The degree of DD (disc darkening on T2*-weighted images), disc protrusions and prolapses, narrowing of disc spaces, dorsal osteophytes and spinal canal stenosis were assessed. Abnormalities were commoner in older subjects, 62% of being seen in those over 40 years old. In subjects aged less than 30 years there were virtually no abnormalities. DD was the most common abnormality, seen in 10% of discs; 57% DD was in subjects aged over 40. DD at the C5/6 level was the most common finding. No differences in abnormal findings between males and females was observed, nor any statistically significant association between DD and other abnormalities. Thus, DD begins later age in the cervical spine than in the lumbar region. Asymptomatic degenerative changes are common on MRI in the cervical spine after 30 years of age.

The effects of the method of death and lapsed time on proton relaxation time T1 in autopsied muscle samples.

RATIONALE AND OBJECTIVES: The variation of measured magnetic resonance T1 relaxation times of autopsied human muscle samples is confusing. Hence, the authors studied rats' muscles to evaluate the effect of fiber type, the relative area of nonmyofiber space, fat and water content, cell death, and the mechanism of death on proton T1. METHODS: Rats were studied on a 0.1 T magnetic resonance device. We studied how death by cervical dislocation, pentobarbital injection, or a combination of these methods, as well as the amount of time lapsed after death, variably affected T1. RESULTS: Death itself did not affect T1, but the mechanism of death did: rats killed by cervical dislocation after ether anesthesia had longer T1 than those killed with an overdose of pentobarbital. T1 was significantly shorter 1 day after death than at 4 hours after and returned to baseline levels within 4 days after death. Repeated warming caused variation in T1 and obscured other possible changes. CONCLUSIONS: Investigation methods should be strictly controlled and standardized before measurements of the relaxation time, T1, of muscle tissue will provide consistent results.

Low-back pain and disk degeneration in children: a case-control MR imaging study.

Thirty-nine 15-year-old children with low-back pain (LBP) and 39 asymptomatic control children were selected from a population of 1,503 children of the same age for a magnetic resonance imaging study of the lumbar spine. Subjects with LBP were matched with control subjects by age, sex, and school class. Disk degeneration (DD) was present in 15 (38%) of the children with LBP and in 10 (26%) of the control subjects. Lumbar degeneration was most frequently associated with disk protrusion and Scheuermann-type changes. Of assessed structural abnormalities (disk protrusion, Scheuermann-type changes, transitional vertebra, and disk space narrowing), only disk protrusion was more common in children of the LBP group than in control subjects. The authors conclude that DD is a frequent finding among children with LBP at the age of 15 years. Asymptomatic (possibly physiologic) DD also is frequently found in children of this age. Whether DD associated with structural changes predisposes to low-back disorders can be confirmed only by means of a longitudinal follow-up study.

Attenuation and contrast enhancement of gynecologic organs and tumors in CT.

CT scans were obtained of 11 normal women and 34 women with gynecologic tumors. Twenty-three of 26 women with known malignant tumors had abnormal CT scans while all control patients had normal. The tumor extent demonstrated by CT correlated with either pathologic or surgical staging in 78%. Contrast enhancement increased the diagnostic yield and accuracy of staging. Attenuation values of the normal uterus and uterine tumors are quite similar prior to contrast medium. After administration of contrast agent the normal myometrium attenuation values increase more than other pelvic tissues. Uterine tumors show substantially less enhancement and show a greater variation of density throughout the tumor than normal myometrium. Density readings are not predictive of histologic type or tumor grade. Tumor was best detected and its extent best seen after high doses of intravenous contrast medium infusion, which should be considered a routine part of the diagnostic evaluation of these patients.

Radiology of uncommon esophageal neoplasms.

The radiographic appearance of 16 uncommon primary esophageal tumors (4 adenoid cystic carcinomas, 3 adenoacanthomas, 4 small cell carcinomas, 2 adenopapillary carcinomas, adenocarcinoma, mucoepidermoid carcinoma and malignant melanoma), is presented. These tumors were found in a retrospective study of 270 esophageal neoplasms. Sufficient radiographic, histologic and clinical data was available to substantiate primary esophageal origin of the tumors. Cylindromas tender to have a smooth surface and either funneled or polypoid appearance. None of the tumors, however, had radiographic appearance readily distinguishable from variable patterns of the common esophageal carcinomas. The age and sex distribution, location as well as prognosis of the rate adenocarcinomas appear to be similar to squamous cell carcinomas. The small cell carcinomas of the esophagus only had an average prognosis of 4 months. The x-ray examination was of little value in predicting local tumor spread, mediastinal metastases or prognosis.

Upper extremity contrast medium infusion in computed tomography of upper mediastinal masses.

Infusion of dilute contrast agent through an upper extremity vein results in marked opacification of the superior vena cava and the ipsilateral subclavian and brachiocephalic veins in computed tomography of the upper mediastinum. Also, the cranial arteries are well opacified. Images obtained by this method display anatomical relationships to better advantage and permit more accurate interpretation of anatomical relationships of the upper mediastinal masses. Improved anatomical details are obtained as compared to noncontrast scans or scans after bolus injection. In cases of suspected venous occlusion, functional diagnostic information is also achieved.