Resistance training reduces susceptibility to eccentric exercise-induced muscle dysfunction in older women.

This study evaluated the effect of age on susceptibility to muscular weakness and damage caused by eccentric (ECC) exercise and determined whether this susceptibility was altered by resistance training. Young and older women performed concentric (CON) and ECC one repetition maximum (1 RM) strength tests of the quadriceps femoris. Older women also performed knee extension training for 12 weeks. An unaccustomed bout of ECC knee extension exercise was performed before and after training, and CON and ECC 1 RM were reassessed for 11 days after the ECC bout. Magnetic resonance imaging was used to evaluate changes in muscle water content associated with muscle damage. Before training, older subjects showed a larger decline in CON (p =.008) and ECC (p =.03) strength induced by the unaccustomed ECC bout, compared with the young subjects. One day following the ECC bout, the older women showed a 24% reduction in CON and a 27% reduction in ECC 1 RM, compared with only 6% (CON) and 10% (ECC) in the younger women. A magnetic resonance imaging evaluation indicated that edema or damage was significantly greater in the older untrained women than it was in young women (p <.05), but the resistance-trained older women showed no greater muscle injury than the young women (p >.05). Resistance-trained older women showed no greater decline than sedentary young women in either CON (p >.05) or ECC (p >.05) strength. In conclusion, sedentary older women are more susceptible to ECC-induced muscle dysfunction, but resistance training reduces this susceptibility.

Radiation doses to infants and adults undergoing head CT examinations.

For routine noncontrast CT examinations of the head, we compared the radiation doses of infant patients aged no more than two years old, with those of "adults" defined as any patient whose weight was greater than 40 kg. Data were obtained for 23 infants, and an equal number of "adults," who underwent CT head examinations between May 1997 and March 1998. Patient CT data acquired included the x-ray tube potential (kVp), mAs, section thickness, and total number of sections. For radiation dosimetry purposes, the head was modeled as a uniform cylinder of water using patient size data obtained from a representative cross-sectional image. CT techniques and patient size data permitted the computation of the mean section doses in the head region, total energy imparted, and the corresponding effective doses. All CT scans were performed at 120 kVp, with an average current-exposure time product of 271 +/- 73 and 340 +/- 0 mAs for infants and "adults," respectively. The radius of the water cylinder used to model the patient head increased from 58 mm for 4 kg newborns to 70 mm for 8 kg infants. For "adults," there was little correlation between the weight of the patient and the mean water equivalent radius of 88 mm (r2 = 0.14). Mean section doses were 44.4 +/- 11.1 mGy for infants, and 44.2 +/- 1.5 mGy for "adults." The energy imparted to infants correlated with patient weight (r2= 0.35) much more than did that of "adults" (r2= 0.02). The average infant energy imparted (66.4 +/- 28.7 mJ) was approximately half the value obtained for "adults" (140 +/- 10 mJ). The average effective dose to the infants (7.6 +/- 3.1 mSv), however, was approximately six times higher than that for "adults" (1.3 +/- 0.1 mSv). There was no significant correlation between patient effective dose and patient mass for either the infant (r2 = 0.12) or the "adult" group of patients (r2= 0.02). Infant doses varied much more than "adult" doses, primarily because of a wider range of x-ray technique factors selected and secondarily due to the variation in infant head size. The observed variability in the computed radiation dose parameters indicates that it should be possible to reduce infant doses routinely in head CT examinations without any adverse effect on diagnostic imaging performance. For such routine head CT scans, the average dose reduction for infants weighing between 4 and 8 kg would be expected to range between 40% and 60%.

Use of muscle functional magnetic resonance imaging with older individuals.

Muscle functional magnetic resonance imaging (mfMRI) has been widely used to study muscle recruitment in exercise in young healthy subjects, but has not been validated or used with older subjects. This study validates and demonstrates the use of mfMRI in older subjects. Subjects consisted of apparently healthy sedentary younger (n = 7) and older (n = 6) women. Proton transverse relaxation (T2)-weighted MRI scans were obtained of the quadriceps femoris at rest and immediately following three bouts of knee extension exercise (50%, 75%, and 100% of untrained 5 x 10 repetition maximum [RM]). Older subjects performed knee extension training for 12 weeks and repeated the MRI scan protocol using the same absolute loads. Training induced a 13% increase in 1 RM and a 25% increase in 5 x 10 RM. Older subjects had higher resting T2 values compared with younger subjects; however, the T2 response to exercise (slope) was similar among groups (young = 0.063+/-0.003, older untrained = 0.055+/-0.011, older trained = 0.053+/-0.008; p > .05). In all cases, T2 increased linearly with load. Trained older subjects showed a lower T2 response when lifting the same absolute load compared with before training, which is consistent with results previously obtained from young subjects. In the older population, mfMRI is appropriate for use and offers benefits over other technologies.

Binocular three-dimensional perception through stereoscopic generation from rotating images.

RATIONALE AND OBJECTIVES: The authors evaluated the clinical utility and potential applications of a binocular three-dimensional (3D) image display in diagnostic radiology. MATERIALS AND METHODS: Rotating video displays of computed tomographic (CT), magnetic resonance (MR) angiographic, and digital subtraction angiographic (DSA) image data were used to generate stereoscopic image displays with a 3D appearance. Eight physicians viewed and scored eight skeletal and eight vascular-interventional studies with a planar display mode and a cathode ray tube. Each physician then viewed the 3D display of the same data and assessed the change in image findings, as well as any corresponding changes in level of diagnostic confidence. RESULTS: Image findings changed in 78 (61%) of the 128 studies after viewing the 3D displays. In 94 (73%) of all 128 studies, the interpreters reported increased confidence in their perception of the findings. Results for the vascular-interventional and skeletal cases were generally very similar. CONCLUSION: Binocular 3D stereoscopic displays from rotating images were reported to provide better image conceptualization and a higher degree of confidence in the findings on the images.

Craniocervical junction venous anatomy on enhanced MR images: the suboccipital cavernous sinus.

BACKGROUND AND PURPOSE: The suboccipital cavernous sinus, a vertebral venous plexus surrounding the horizontal portion of the vertebral artery at the skull base, provides an alternative pathway of cranial venous drainage by virtue of its connections to the cranial dural sinuses, the vertebral venous plexus, and the jugular venous system. Knowledge of the anatomy of this system facilitates interpretation of images and might reduce the number of false-positive diagnoses of lesions, such as adenopathy or schwannoma. We hypothesized that this circulation could be visualized on contrast-enhanced, fat-suppressed T1-weighted MR images. METHODS: The craniocervical junctions of 14 patients were scanned using fat-suppressed, contrast-enhanced, T1-weighted MR sequences and evaluated for visibility of the following venous structures: suboccipital cavernous sinus, vertebral artery venous plexus, anterior and posterior condylar veins, vertebral venous plexus, internal jugular vein, and the marginal sinus. Both the right and left sides were assessed in at least two planes. The venous diameters were also measured. RESULTS: All the evaluated venous structures were seen routinely in all three planes, with the exception of the posterior condylar vein, known to be variably present, which was seen only one third of the time in the sagittal plane and two thirds of the time in the other planes. The posterior condylar vein also showed the greatest variability in size and symmetry. CONCLUSION: The suboccipital cavernous sinus and most of its associated venous circulation at the skull base are easily identified on contrast-enhanced, fat-suppressed T1-weighted MR images. The posterior condylar vein, known to be variably present, was not well seen in the sagittal plane and displayed the greatest variability in size and symmetry.

Pituitary gland. Variable signal intensities on MRI. A pictorial essay.

The anterior pituitary gland may exhibit high signal on T1-weighted (T1w) images and/or low signal on T2-weighted (T2w) images in several normal and pathological states. High T1w signal may be seen in normal fetuses, neonates, and in pregnant and postpartum women. It may also occur in Rathke's cleft cyst, craniopharyngioma, subacute hemorrhage, manganese deposition, melanoma, dermoid, and lipoma. Low T2w signal may be seen in hemorrhage, calcification, cystic lesion, hemochromatosis, melanoma, and vascular lesions. These are described and illustrated.

Giant cervical epidural veins after craniectomy for head trauma.

Markedly dilated cervical epidural veins and right upper extremity weakness developed in a 43-year-old man 4 months after contralateral craniectomy for head trauma. After cranioplasty, his symptoms improved markedly and the size of the veins returned to normal. These findings suggest that enlarged cervical epidural veins may occur without an underlying vascular lesion and that upper extremity weakness may occasionally be attributable to spinal cord venous stasis.

Predictive signs of discogenic lumbar pain on magnetic resonance imaging with discography correlation.

STUDY DESIGN: The correlation between discogenic lumbar pain and disc morphology was investigated by using magnetic resonance imaging and discography. OBJECTIVES: To assess the various pathologic parameters seen on magnetic resonance imaging in patients with discogenic lumbar pain and to correlate them with observations on discography. SUMMARY OF BACKGROUND DATA: Although numerous previous studies on the subject have been performed, the correlations between various pathologic findings on magnetic resonance imaging and pain reproduction by provoked discography have not been explained fully. METHODS: One hundred and one lumbar discs in 39 patients were studied with magnetic resonance imaging and pain provocation discography. When pain reproduction under discography was concordant, various pathologic parameters on magnetic resonance imaging were analyzed by three statistical parameters to determine the associated magnetic resonance imaging findings. RESULTS: Radial tears commonly are demonstrated on magnetic resonance imaging in discs with concordant pain on discography. The presence of these tears is not a reliable predictor of a painful disc on discography. Although a high-intensity zone on T2-weighted images is a relatively reliable predictor of pain, the statistical values were lower than those in previous studies. Massive degeneration and severe disc height loss were rare in this population. These findings were good predictors of pain on disc injection. CONCLUSIONS: Although the lumbar intervertebral discs with posterior combined anular tears are likely to produce pain, the validity of these signs for predicting discogenic lumbar pain is limited.

Self-induced ethmoidectomy from rhinotillexomania.

A 53-year-old woman with a long history of compulsive nose picking (rhinotillexomania) presented with a large, self-inflicted nasal septal perforation and right-sided penetration of the ethmoidal sinus, or "ethmoidectomy."

Smaller format, laser camera-generated images: acceptability and cost savings.

RATIONALE AND OBJECTIVES: To evaluate the use of laser-generated smaller images in neuroradiologic practice. MATERIALS AND METHODS: Computed tomographic (CT) scans of the heads of five subjects were obtained at bone and brain windows in three formats: 12:1 (12 images on a 35 x 43-cm film), 15:1 and 20:1. Two laser-camera systems were used. Images were measured, physically separated, and reconstructed as a 35 x 43-cm ensemble; they were presented randomly to seven radiologists who assessed image size and interpretability. Observer preference was also noted. One camera system was evaluated for contrast and spatial resolution by a medical physicist. RESULTS: These were negligible differences in image area between the 15:1 and 20:1 formats. No discernible differences in quality were found among the three formats. The 12:1 images were preferred by the radiologists, but the 20:1 images were deemed acceptable. Annualized cost savings of 46.7%, or $46,650, were projected for adoption of the 20:1 image format for neuroradiologic CT and magnetic resonance imaging. CONCLUSION: No major differences were detected in image area between the 15:1 and the 20:1 image formats or in image quality among the three formats. Use of a smaller image format may result in substantial cost savings.

Magnetic resonance imaging of cerebrospinal fluid leak and tamponade effect of blood patch in postdural puncture headache.

This prospective study examined the efficacy of magnetic resonance imaging (MRI) in visualizing cerebrospinal fluid (CSF) leak in patients with postdural puncture headache (PDPH) and determining the spread of the blood patch in the epidural space and the extent of tamponade on the thecal sac. After obtaining institutional review board approval, five patients with symptomatic PDPH after 3 days of failed conservative treatment were included in this study. MRI using proton density (PD) and T2-weighted imaging was performed on all patients and CSF flow studies were done on one patient. All patients received 20 mL of blood in the epidural space. They remained supine for 45 min, and repeat MRI studies were performed. Extent of the spread of blood in the epidural space was measured. A visual analog scale of 0-10 was used to evaluate the headache. All patients had severe postural headache with nausea/vomiting. Preblood patch MRI showed extrathecal CSF and hemosiderosis indicating the site of dural puncture in four patients. The postprocedure MRI demonstrated the blood patch as a large extradural collection with anterior displacement of the thecal sac, the mean spread being 4.6 intervertebral spaces. The tamponade effect of the blood patch was observed on PD, T2-weighted, and CSF flow images. All patients experienced immediate resolution of their symptoms. This study suggests that using MRI, the site of the CSF leak, the tamponade effect of the blood patch, and its spread in the epidural space can be documented.

The long-term effects of pregnancy and bromocriptine treatment on prolactinomas--the value of radiologic studies.

OBJECTIVE: To evaluate the long-term effects of pregnancy and bromocriptine treatment on prolactin-secreting pituitary tumors in women undergoing infertility treatment for prolactinomas. METHODS: The records of 17 patients with prolactinomas were reviewed. Data regarding age, prepregnancy baseline and postpartum serum prolactin levels, and radiologic studies including CT or MRI were assessed. 16 patients were treated with bromocriptine before achieving pregnancy. Bromocriptine therapy was resumed after delivery for the duration of 1 to 14 years. RESULTS: 45% of pregnancies did not affect the size of prolactinomas, 27% of pregnancies showed a decrease in size of prolactinomas or radiologic evidence of resolution of the tumor and 27% of pregnancies demonstrated radiologic increase in the size of prolactinomas. CONCLUSIONS: It is safe for patients with prolactinomas to achieve pregnancy following bromocriptine treatment. Pregnancy may lead to a slight decrease in the size of prolactinomas, increase in size, no change, and in some cases, complete resolution. There were no visual field changes during the pregnancies. Pregnancy and long-term bromocriptine treatment may be helpful in reduction of the size of the tumor.

Intrinsic cervical spinal cord deformation on MRI: "the distorted 'H' sign".

Extrinsic and intrinsic pathologic processes involving the spinal cord can affect its gross morphologic appearance. Contour-related abnormalities of the spinal cord can be determined by both noninvasive and invasive imaging techniques. Detailing internal dysmorphism of the spinal cord is more difficult to determine because the internal architecture of the cord is not usually visualized. Now magnetic resonance (MR) imaging can readily demonstrate the central "H" configuration of the normal spinal gray matter on axial T2* gradient-recall echo pulse sequences; thus, it should also be capable of demonstrating distortions of it. We initially reviewed 55 abnormal cervical spine 1.5-T MR imaging studies. Of 37 large lesions, 31 deformed the "H" whereas 18 small lesions did not. To compare potential differences in visualization of the "H" by MR scanners of different field strengths (1.5-0.5 T), a total of 125 additional patients were reviewed at different State University of New York (SUNY) sites. Visualization of the "H" varied from 51.4% at 1.5 T to 18.4% at 0.5 T. As resolution of the spinal cord increases on MR imaging, it becomes possible to more accurately map the altered cord "interior," which may have a detectable clinical (neurologic) counterpart.

Gradient echo imaging of the lumbar spine.

Journal articles have presented pro and con views of gradient recalled echo (GRE) imaging of the lumbar spine, while it has been illustrated in textbooks that have advanced its diagnostic applicability. This paper reappraises GRE in light of evolving MRI technology. The conspicuity of anatomic structures on axial T1-weighted (T1W) spin-echo (SE) images were matched with T2 GRE images in 55 patients referred for evaluation of low back pain. Disc herniations were hyperintense on GRE images and readily separable from hypointense spondylophytes.

Anti-Ro(SS-A) autoantibodies in central nervous system disease associated with Sjögren's syndrome (CNS-SS): clinical, neuroimaging, and angiographic correlates.

OBJECTIVE: To examine in Sjögren's syndrome (SS) the interrelationship between the presence of the anti-Ro(SS-A) antibody response and (1) concomitant presence and type (ie, focal or nonfocal) of CNS disease (CNS-SS), (2) cross-sectional brain MRI or CT, and (3) abnormal cerebral angiography. METHODS: Neurologic, neuroimaging, and angiographic features of CNS-SS patients were correlated with the presence of precipitating anti-Ro(SS-A) autoantibodies detected by gel double-immunodiffusion or quantitative ELISA, which detects antibodies directed against the 60-kd peptide. Statistical analyses were performed using Fisher's exact test (two-tailed) with Haldane's adjustment and odds ratio with Cornfield 95% confidence intervals. RESULTS: Precipitating antibodies against the Ro(SS-A) antigen, determined by gel double-immunodiffusion, were present in an increased frequency in CNS-SS patients with (1) documented clinical CNS disease, (2) focal clinical CNS manifestations and serious complications, (3) large regions of increased signal intensity, consistent with ischemia/infarcts on brain MRI scans or regions of decreased attenuation consistent with infarcts on CT, and (4) abnormal cerebral angiograms consistent with small-vessel angiitis. Finally, the anti-Ro(SS-A) antibody response in CNS was directed against the 60-kd peptide specificity, determined by ELISA. CONCLUSIONS: Clinical, neuroimaging (cerebral CT), and angiographic observation suggest that a subset of anti-Ro(SS-A) antibody-positive, in contrast with -negative, CNS-SS patients have more serious and extensive CNS disease, some with frank cerebral angiopathy. Anti-Ro(SS-A) antibodies are postulated to play a role in mediating or potentiating vascular injury in CNS-SS.

Facial trauma and 3-D reconstructive imaging: insufficiencies and correctives.

PURPOSE: To address the clinical relevance of and optimal technique for 3-D CT imaging of facial trauma. METHODS: Bioengineered cadaveric models were developed to enhance the concepts of LeFort. Diverse CT imaging techniques were applied to obtain optimal data sets for processing on various 3-D workstations. The fidelity of the 3-D reconstructions was determined by comparison with photographs of the cadaveric models. Optimized 3-D images were then used in conjunction with the initial 2-D data sets to assess whether additional accuracy was contributed by the 3-D images in the evaluation of modeled facial fractures. RESULTS: Image definition was heavily dependent upon the specific 3-D reconstruction algorithm and the processor utilized. Orbital fractures were best imaged when 1- to 1.5-mm coronal sections were processed on an advanced 3-D workstation. The 3-D CT images resulted in additional accuracy in the 2-D CT evaluation of facial fractures in 29% of trials. CONCLUSIONS: We believe that bioengineered models of facial trauma--matched with appropriate CT scanning parameters--facilitate graphically reliable 3-D reconstructive imaging. 3-D reconstructions can improve accuracy in the 2-D CT evaluation of facial trauma.