Examination of joint space by magnetic resonance imaging in anatomically normal knees

The medial and lateral knee joint spaces of 184 patients who had anatomically normal knees were measured by using magnetic resonance imaging (MRI) method. The findings were compared according to age, sex, height, and body mass index changes of the individuals and the mean values of medial and lateral knee joint spaces were calculated in every group. The results show that in an anatomically normal population, all the individuals have larger lateral knee joint spaces than medial knee joint spaces. The patients lose knee joint space regularly with increasing age. Children have larger knee joint spaces than adults. Men have larger knee joint spaces than women. The knee joint space size of the patients increase regularly with increasing height up to 180 cm. The patients, who are taller than 180 cm do not show any marked difference in joint space size, when compared with the patients whose heights differ in between 171–180 cm. Knee joint space size is not related to the body mass index of the individual. © 1996 Wiley-Liss, Inc.     

Histopathological changes in the infrapatellar fat pad in an experimental rabbit model of early patellofemoral osteoarthritis

Background

The purpose of this study was to characterise the histopathological changes in the infrapatellar fat pad (IPFP) in the early stage of patellofemoral osteoarthritis (PFOA).

Neurologic recovery according to early magnetic resonance imaging findings in traumatic cervical spinal cord injuries

The aim of this study was to determine the usefulness of early magnetic resonance imaging findings in predicting neurologic recovery at or below the injured level in traumatic cervical spinal cord injuries. Thirty patients with traumatic cervical spinal cord injuries were included. All of the patients received a magnetic resonance imaging and a neurologic examination in the emergency room, within 7 days of injury and at 6 months following the injury. To quantify neurologic recovery below the injured level, we modified clinical scales, particularly the motor ratio and the sensory ratio. We used the neurologic level to quantify recovery around the injured level. We assessed neurologic recovery according to MRI patterns and lesion extents. The pure hemorrhagic MRI pattern was not observed. In edematous and mixed types, the improvement of neurologic levels was not significantly different. The motor ratio and sensory ratio improved significantly more in edematous type patients than in mixed type patients. Based on MRI lesion extent, the improvement of neurologic levels was not significantly different, and motor ratio and sensory ratio improved significantly more in those with one or two segments involved than in those with more than two segments involved. In conclusion, early MRI pattern and lesion extent after traumatic cervical spinal cord injury may provide important information to help predict neurologic recovery, especially below the injured level.     

Changes of meniscal interhorn distances: an in vivo magnetic resonance imaging study

The aim of this study was to evaluate the changes of the internal (IID) and external meniscal interhorn distance (EID) of the medial and the lateral meniscus under loading. Sagittal magnetic resonance images of 15 knees were studied. The medial and lateral meniscus were examined with the knee at 0° and 30° of flexion, under no load, with load equal to 50% of body weight and with load equal to 100% of body weight. Under no load, the mean IID was 19.9 mm for the medial meniscus and 12.3 mm for the lateral meniscus and the mean EID was 44.6 mm for the medial meniscus and 34.4 mm for the lateral meniscus. Under load equal to 50% and 100% of patient's body weight, there was a significant increase in both distances (p < 0.05). Under constant loading, flexion of the knee from 0° to 30°, decreased the EID of both menisci. In conclusion, loading increases both IID and EID. Knee position affects only the EID. The quality of magnetic resonance images may affect the reliability of such measurements.     

In vivo study of experimental pneumococcal meningitis using magnetic resonance imaging

Background  

Magnetic Resonance Imaging (MRI) methods were evaluated as a tool for the study of experimental meningitis. The identification and characterisation of pathophysiological parameters that vary during the course of the disease could be used as markers for future studies of new treatment strategies.     

Incidental extraspinal findings on magnetic resonance imaging of intervertebral discs

Introduction

We aimed to evaluate pathological extraspinal findings and congenital anomalies/anatomical variations that were incidentally detected on the magnetic resonance imaging (MRI) scans of intervertebral discs, to find the frequencies of these incidental findings, and to emphasise the clinical importance of them.

Material and methods

A retrospective study including 1031 consecutive patients (730 females and 301 males, with a median age of 46 years) was conducted by evaluating a total of 1106 MRI examinations of intervertebral discs. Examinations were performed with a 1.5 T MRI unit. Incidental findings were classified as pathological findings and congenital anomalies/anatomical variations.

Results

The percentages of incidental extraspinal pathological findings and congenital anomalies/anatomical variations were 16.6% (95% confidence interval (CI): 14.4–18.8) and 3.7% (95% CI: 2.6–4.3), respectively. The percentage of incidental extraspinal pathological findings on cervical spinal MRI was 25.7% (95% CI: 20.1–31.7), thyroid nodules being the most common incidental findings. On thoracic spinal MRI (n = 19), inferior pole thyroid nodules were demonstrated as incidental extraspinal pathological findings, with a percentage of 10.5% (95% CI: 9.6–11.5). On lumbar spinal MRI, incidental pathological findings were detected with a percentage of 14.2% (95% CI: 11.9–16.6), while the percentage of congenital anomalies/anatomical variations was 4.8% (95% CI: 3.4–6.3). Eventually, 6.5% (95% CI: 2.6–9.4) of all cases with incidental extraspinal pathological findings underwent surgery.

Conclusions

On MRI examination of intervertebral discs, paying attention to incidentally detected pathological extraspinal findings and congenital anomalies/anatomical variations is very important due to the fact that they can alter the treatment of the patient or affect the patient''s life.     

Calvarial diploic venous channels: an anatomic study using high-resolution magnetic resonance imaging

Background

The calvarial diploic venous channels (CDVCs) are well-known intraosseous structures, but their distribution and anatomofunctional implications are not fully understood.

Objective

To investigate the architecture of CDVCs using high-resolution magnetic resonance (MR) imaging.

Method

This prospective study enrolled 43 male and 37 female outpatients who underwent a 3.0-T MR imaging equipped by a 32-channel head coil. T1-weighted imaging covering the whole cranial vault was performed after gadolinium injection. In addition, one-piece orbitozygomatic craniotomy was performed in three cadaveric heads to observe the interruption of the CDVCs.

Results

The CDVCs showed irregular contours and peculiar branching patterns with four common major pathways: the pteriofrontparietal (PFP), frontoorbital (FO), occipitoparietal (OP), and occipitocervical (OC) routes. The proximal PFP coursed as a single trunk and divided into several branches at the level of the frontal eminence. The orbital part of the FO continued to the subcutaneous vein via the supraorbital rim. The PFP and the pterional part of the FO fused proximally with the sphenoparietal sinus and descended as the middle meningeal vein. The OP coursed in the superoinferior direction and connected the junction part of the transverse-sigmoid sinus to the parietal superior sagittal sinus. The OC occurred as a single trunk in the median occipital bone, drained extracranially, and joined the suboccipital venous channels.

Conclusions

The CDVCs seem to be a relatively consistent network functioning not only as conduits connecting the intracranial dural sinuses but also as pathways to the extracranial venous systems. High-resolution MR imaging is useful for investigating the CDVCs.     

Working memory for order and the parietal cortex: an event-related functional magnetic resonance imaging study

Memory for order information has been tied to the frontal lobes, however, parietal activation is observed in many functional neuroimaging studies. Here we report functional magnetic resonance findings from an event-related experiment involving working memory for order. Five letters were presented for storage, followed after a delay by two probe items. Probe items could be separated by zero to three positions in the memory set and subjects had to indicate whether the items were in the correct order. Analyses indicate that activation in left parietal cortex shows a systematic decrease in activation with increasing probe distance. This finding is consistent with an earlier study in which we suggested that parietal cortical regions mediate the representation of order information via magnitude codes.     

The left parietal cortex and motor intention: an event-related functional magnetic resonance imaging study

Traditionally the posterior parietal cortex was believed to be a sensory structure. More recently, however, its important role in sensory-motor integration has been recognized. One of its functions suggested in this context is the forming of intentions, i.e. high-level cognitive plans for movements. The selection and planning of a specific movement defines motor intention. In this study we used rapid event-related functional magnetic resonance imaging of healthy human subjects to investigate the involvement of posterior parietal cortex in motor intention in response to valid imperative cues. Subjects were provided with either neutral, motor or spatial cues. Neutral cues simply alerted, motor cues indicated which hand to use for response, and spatial cues indicated on which side the target would appear. Importantly, identical targets and responses followed these cues. Therefore any differential neural effects observed are independent from the actual movement performed. Differential blood oxygen level dependent signal changes for motor vs. neutral as well as motor vs. spatial cue trials were found in the left supramarginal gyrus, as hypothesized. The results demonstrate that neural activity in the left supramarginal gyrus underlies motor plans independent from the execution of the movement and thus extend previous neuropsychological and functional imaging data on the role of the left supramarginal gyrus in higher motor cognition.     

妊娠中期胎脑海马发育的高场强磁共振成像研究

目的 探讨海马结构(HF)在妊娠中期的形态发育变化以及HF在形态和体积发育上是否存在非对称性.方法 收集2008年1月至2009年6月终止妊娠的胎儿标本46例,胎龄为13 ～ 22周,其中男19例、女27例.使用7.0 T MRI对46例胎儿标本进行胎脑扫描,使用Amira 4.1软件进行HF的三维重建并计算其体积.结果 7.0 T MRI扫描图像显示HF形态非常清晰,妊娠中期胎儿HF形态发育是一个逐渐卷曲的过程.左右两侧HF体积随着孕龄的增加而增大(左侧:rs=0.866,右侧:rs=0.889,均P＜0.01).左侧HF体积为0.211 312 cm3(0.016 293 ～ 0.276 762 cm3),右侧为0.217 693 cm3(0.018 362～0.308 548 cm3),两侧HF体积比较显示胎儿右侧HF体积比左侧大(P＜0.05).结论 妊娠中期胎儿HF体积与孕龄呈正相关,左右两侧HF体积增长存在侧别差异.     

Complex venous anomalies: magnetic resonance imaging findings in a 5-year-old boy

We report magnetic resonance imaging (MRI) findings of a very unusual venous anomaly case. A 5-year-old boy who had surgical repair of coarctation of the thoracic aorta was referred to our department for evaluation of an enlarged venous structure anterior to the aorta, which had been noted during the surgery. Contrast enhanced dynamic MRI revealed partial anomalous pulmonary venous return to the left azygos vein, double inferior and superior vena cava with the left azygos continuation of the left superior vena cava. The recognition of venous anomalies allows correct planning of surgical and interventional procedures. MRI is a valuable imaging tool providing detailed anatomical information.     

Comparison of thermal damage calculated using magnetic resonance thermometry, with magnetic resonance imaging post-treatment and histology, after interstitial microwave thermal therapy of rabbit brain

Clinical application of high-temperature thermal therapy as a treatment for solid tumours requires an accurate and close to real-time method for assessing tissue damage. Imaging methods that detect structural changes during heating may underestimate the extent of thermal damage. This is due to the occurrence of delayed damage manifested at tissue locations exposed to temperatures lower than those required to cause immediate structural changes. An alternative approach is to measure temperature and then calculate the expected damage based on the temperature history at each tissue location. Magnetic resonance (MR) imaging methods now allow temperature maps of the target and surrounding tissues to be generated in almost real-time. The aim of this work was to evaluate whether thermal damage zones calculated on the basis of MR thermometry maps measured during heating correspond to actual tissue damage as measured after treatment by histological methods and MR imaging. Four male rabbits were treated with high-temperature thermal therapy delivered in the brain by a single microwave antenna operating at 915 MHz. MR scanning was performed before, during and after treatment in a 1.5 T whole-body scanner. Temperature maps were produced using the proton resonance frequency (PRF) shift method of MR thermometry. In addition, conventional T1-weighted and T2-weighted spin-echo images were acquired after treatment. Thermal damage zones corresponding to cell death, microvascular blood flow stasis and protein coagulation were calculated using an Arrhenius analysis of the MR temperature/time course data. The calculated zones were compared with the lesions seen on histopathological examination of the brains which were removed within 6-8 h of treatment. The results showed that calculated damage zones based on MR thermometry agreed well with areas of damage as assessed using histology after heating was completed. The data suggest that real-time calculations of final expected thermal damage based on an Arrhenius analysis of MR temperature data may provide a useful method of real-time monitoring of thermal therapy when combined with conventional T2-weighted images taken after treatment.     

Clinical, electrophysiological and magnetic resonance imaging findings in carpal tunnel syndrome

OBJECTIVE: To assess magnetic resonance imaging (MRI) findings in carpal tunnel syndrome (CTS) and to compare them with electrophysiological findings. METHODS: Routine motor and sensory nerve conduction examinations and needle EMG were performed in 42 hands of 22 patients, who were clinically diagnosed as having CTS in at least one wrist. RESULTS: Of 29 wrists with clinically and electrophysiologically confirmed CTS, MRI could detect abnormality in 18 wrists (62%). Median nerve was found to be abnormal in MRI in 1 of 2 wrists with suspected clinical symptoms and proven CTS by electrophysiological examination. MRI was abnormal in 1 of 4 wrists with normal clinical and electrophysiological examination. MRI was abnormal in 46, 7% of wrists with mild CTS, in 61.6% of moderate CTS and in 100% of severe CTS. Volar bulging of the flexor retinaculum was detected in a single wrist with severe CTS. Enlargement of median nerve was observed in 3 of 5 severe CTS. CONCLUSION: MRI could be useful in the diagnosis of unproven cases in CTS. It also provides anatomical information that correlate well with electrophysiological findings in regard of the severity of median nerve compression.     

Magnetic field distribution in the presence of paramagnetic plates in magnetic resonance imaging: a combined numerical and experimental study

The amount and geometric distribution of paramagnetic components in tissue is considered as the basis of T2*-weighted magnetic resonance imaging (MRI). Such techniques are routinely applied for assessment of iron in parenchymal organs such as the liver (hemosiderosis). Furthermore, susceptibility sensitive MRI is discussed as an alternative method to x-ray techniques for quantitative assessment of paramagnetic spongy bone components in patients with osteoporosis. The presented work is dedicated to systematically examining the possible influences of macroscopic arrangements of paramagnetic plates on the magnetic field. In a theoretical approach magnetic field distribution was simulated applying decomposition of the plates in single dipoles. Plate size and distances between parallel plates, as well as plate orientation with respect to the static field, were varied for these numerical simulations. Experiments on corresponding plate arrangements were carried out on a 3 T whole body MR scanner using the field-sensitive MR sequence technique for B0 field mapping. Further examinations were carried out on a bone preparation of the femur, where T2* maps were measured and analyzed on a pixel-by-pixel basis at two orientations with respect to the static field. A series of experiments were performed using isotropic and anisotropic volume elements in three-dimensional gradient echo sequences. Resulting magnetic field distributions in the experimentally recorded B0 field maps were in good agreement with the numerical simulations. Field distortions dominated in areas close to the plates and especially near the edges. Those areas showed strong local field gradients, leading to pronounced signal dephasing effects. The examination of the bone preparations revealed different T2* values for identical regions in the bone when the orientation of the bone or the pixel geometry was changed with respect to the magnetic field. Those effects amounted to nearly 70% (22.9 ms versus 13.6 ms in a region of interest in the femur) for 90 degrees rotation of the femur in the magnetic fields. The orientation of anisotropic picture elements with constant size also showed a strong influence on the derived T2* value (up to 80%, increasing with anisotropy of picture elements).     

Diagnostic imaging in sheep hepatic fascioliasis: ultrasound,computer tomography and magnetic resonance findings

Radiological features and biochemical changes were investigated during the parenchymal and ductal phases of chronic Fasciola hepatica infection in sheep. The activities of plasma aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (GGT), plasma levels of IgG anti- F. hepatica and serial ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) findings were studied in eight sheep infected with 150 F. hepatica metacercariae. Experimental fluke infection provoked an increase in plasma level of IgG directed against F. hepatica and in plasma LDH and AST activities from 4 weeks after infection. Enzyme activities did not significantly differ from the baseline after 15 and 12 weeks for LDH and AST, respectively. GGT activity increased from 9 weeks postinfection and still remained significantly elevated at 18 weeks. In the parenchymal phase, both CT and MRI showed nodular lesions in five animals and MRI could also detect early tracks in the subcapsular area in three sheep. Ultrasound findings were nonspecific in this phase. Ductal dilatation was shown by ultrasound, CT and MRI in almost all animals, although MRI was inferior to CT in depicting a mild ductal dilatation. Moving echogenic forms in the dilated bile ducts were observed by ultrasound from 9 weeks postinfection in seven of the eight sheep. Moving worms were only demonstrated in four sheep at CT and in a single sheep at MRI. This study shows that radiological findings may be useful in studies of fluke-induced liver damage.     

In vivo microelectrode localization in the brain of the alert monkey: a combined radiographic and magnetic resonance imaging approach

A technique is described for in vivo localization of microelectrodes during single-unit recording in the alert monkey. Four hollow glass spheres filled with copper sulfate and iohexol were affixed to the surface of the animal's skull prior to the acquisition of a series of coronal magnetic resonance (MR) images. These reference beads were visible in both X-ray and MR images. Cranial recording chambers were then implanted bilaterally over the amygdaloid complex. A microelectrode was advanced to various depths in the subject's brain. At each selected microelectrode site, five radiographs were obtained and a small electrolytic lesion was made. Based on the data from the radiographs, we computed the position of the microelectrode tip at each site relative to the reference beads. With a precision of 625 m, this method was used to predict the neuroanatomical location of ten microlesions placed in both subcortical and cortical structures. Postmortem histological analysis revealed that the actual location of the lesions closely matched predictions arrived at using the X-ray/MRI localization technique. This technique thus provides an accurate, reliable and noninvasive method for in vivo localization of microelectrode recording sites.     

Clinicopathological study of invasive ductal carcinoma with large central acellular zone: special reference to magnetic resonance imaging findings

Invasive ductal carcinoma (IDC) with central acellular zone is sometimes encountered, but its clinicopathological features have not yet been fully investigated. The clinicopathological features of 10 resected cases of IDC with a large central acellular zone were investigated. The tumor size ranged from 6 to 28 mm with a mean of 14.3 +/- 6.9 mm. Contrast-enhanced magnetic resonance imaging (MRI) showed a ring-like appearance in the tumor. Sagittal fat-suppressed T2-weighted MRI had very high to intermediate signal intensity in a central area. Histologically, cancer tissue was located in the periphery of the tumor with a ring-like pattern and a large central area was occupied by acellular amorphous tissue that was strongly stained by alcian blue. Lymph vessel permeation was seen in eight cases. Among the tumors with focal enhancement in the central areas >1 cm in diameter on contrast MRI, marked increase of microvessel was observed in the enhanced spot. The mean of p53 and Ki-67 labeling indices was 56.2% and 36.3%, respectively. IDC with a large central acellular zone presenting with characteristic MRI should be noted as a new morphological entity.     

Comparison of two methods for the estimation of subcortical volume and asymmetry using magnetic resonance imaging: a methodological study

Purpose

The subcortical brain structures are associated with other structures of nervous system; therefore, they have major influence on sensory–motor, limbic and cognitive information processing. Magnetic resonance imaging provides a detailed knowledge of normal and diseased anatomical structures for medical research. The aim of the current study was to compare the volumes of subcortical brain structures and determine the probable volumetric asymmetry in healthy subjects using stereological (point-counting) and semi-automatic segmentation methods.

Methods

MR scans were obtained from 30 subjects (17 males, 13 females) free of any psychiatric, neurological or cognitive impairment. MR images were analyzed by using stereological (point-counting) and semi-automatic segmentation methods.

Results

We did not find any significant differences among the subjects with respect to gender using both methods. This study showed no significant asymmetry in subcortical structures according to methods. Also, no significant difference was found between point-counting and semi-automated segmentation methods for the volumes of subcortical structures (p > 0.05).

Conclusion

From these results, it can be concluded that the semi-automated segmentation method and stereological technique can be used for reliable volume estimation of subcortical structures. However, the stereological method takes less time than semi-automated segmentation; it is simple, reliable and inexpensive. Further studies are required with larger samples in order to support these data.