Radial-sequence magnetic resonance imaging in evaluation of acetabular labrum

We investigated the usefulness of a radial-sequence magnetic resonance imaging (MRI) technique in the visualization of the acetabular labrum, which surrounds the acetabulum. In 22 hip joints of 12 volunteers, T2-weighted images were obtained on 24 radial planes of the acetabular rim, set at 15°-intervals, using the small tip angle gradient echo method. We examined 7 planes in the weight-bearing portion. The acetabular labrum in the weight-bearing portion was depicted in good contrast to the surrounding tissues. The shape of the labrum differed among individuals and also in the anterior and posterior portions of the labrum. The signal intensity of the labrum was low or partially moderate. There was a high signal intensity band on the base of the acetabular labrum in several portions, which should be carefully interpreted to avoid confusion with abnormality. We concluded that radial-sequence MRI could be a useful technique for evaluation of the condition of the acetabular labrum in the weight-bearing portion. Received for publication on Dec. 9, 1998; accepted on April 8, 1999     

An occult acetabular fracture revealed by magnetic resonance imaging

The authors describe the case of a 35-year-old man with an injury to the left hip joint. When examined at the surgical ward, the patient complained of pain and restricted motion of the left hip. No traumatic changes in the left hip joint were revealed on X-ray and CT examination. When checked-up 13 days later, the patients still complained of persistent pain and restricted movement. Because of the discrepancy between the results of X-ray and clinical examinations, magnetic resonance imaging was recommended. This revealed an infraction of the roof of the acetabulum without trauma to the soft joint tissues and adjacent muscles. A retrospective analysis of the X-ray and CT examination data showed an infraction of the acetabular roof on CT scans. The authors emphasize the role of non-invasive magnetic resonance imaging in the diagnosis of occult fractures.     

A study of the anatomy of the caudal space using magnetic resonance imaging

We have studied, in 37 adult patients, the anatomy of the sacral extradural (caudal) space using magnetic resonance imaging. The sacrococcygeal membrane (SCM) could not be detected in 10.8% of patients. The maximum depth of the caudal space adjacent to the SCM was beneath the upper third of the SCM in more than 90% of patients (mean depth 4.6 mm; range 1.0-8.0 mm). The shortest linear distance from the dura to the upper limit of the SCM varied considerably (60.5 mm; 34-80 mm) as did the volume of the caudal space excluding the foraminae and dural sac (14.4 cm3; 9.5-26.6 cm3). The dimensions of the caudal space and their variability have implications for clinical practice and a knowledge of these dimensions may increase both the reliability and safety of caudal techniques in adult patients.      

Medial tibial plateau morphology and stress fracture location:A magnetic resonance imaging study

AIM To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging(MRI).METHODS A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years(range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI.RESULTS Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially(AM type), six posteromedially(PM type), and five posteriorly(P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI.CONCLUSION We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau.     

Surgical decompressive procedures for cervical spondylotic myelopathy. A study using magnetic resonance imaging

Twenty-two patients who underwent a surgical decompressive procedure for cervical spondylotic myelopathy were studied with magnetic resonance imaging to evaluate the effectiveness of their decompressive procedures. Twelve patients were judged as adequately decompressed by magnetic resonance imaging criteria. Ten patients exhibited evidence of residual cord indentation. This along with cord atrophy, gliosis, and abnormal spine curvature presumably contributed to residual deficit in several patients. One patient underwent a second decompressive procedure for residual cord indentation, which subsequently improved, as seen on his second postoperative magnetic resonance image. Magnetic resonance imaging was useful in distinguishing mechanical problems from intrinsic cord damage or atrophy. Magnetic resonance imaging should be used after operation in patients with residual deficit to detect patients who may be considered for a second decompressive procedure.     

A clinical study on the diagnosis of spinal cord tumor using magnetic resonance imaging

Thirty-five patients with a variety of spinal cord tumors were studied by magnetic resonance imaging (MRI). In 22 out of these cases, the efficacy of Dimeglumine gadopentetate (Gd-DTPA) in enhancing MRI was also investigated. The results were as follows: (1) MRI was capable of discerning the level of tumors. (2) MRI was able to distinguish intramedullary from extramedullary tumors. MRI, however, could not always differentiate extradural from intradural tumors. (3) Some cases of lipoma, arteriovenous malformation and hematoma were diagnosed by MRI. (4) Gd-DTPA was found to be effective in enhancing MRI in all cases of spinal cord tumors with exception of two cases of arteriovenous malformations. In conclusion, MRI is very useful in diagnosing spinal cord tumors. MRI, when enhanced with Gd-DTPA, is capable of revealing the content of tumors but also differentiating intramedullary tumors from surrounding edema and syrinx.     

Age-related magnetic resonance imaging morphology of the menisci in asymptomatic individuals

In 82 asymptomatic subjects aged 8–62 years we evaluated the menisci by magnetic resonance imaging (MRI). Using a 1.0-tesla imager spin-echo sequences (SE 700/20), partial-saturation sequences (500/10), and short-time inversion-recovery sequences (1600/130/30) were performed. For grading the degeneration of the meniscus, a standard classification (grades 0–4) was used. Positive MRI findings correlated with the patients' age. In SE sequences, a grade 0 meniscus was found in 45.5% of all cases, grade 1 in 33.2%, grade 2 in 16.1%, grade 3 in 4.5%, and grade 4 in 0.7%. In PS sequences, we found grade 0 in 23.9%, grade 1 in 27.5%, grade 2 in 31.5%, grade 3 in 15.9%, and grade 4 in 1.1 %. In STIR sequences, we found grade 0 in 56%, grade I in 25.4%, grade 2 in 11.1%, grade 3 in 6%, and grade 4 in 1.6%. Correlation of meniscus degeneration with subjects' age showed an increase of grade 3 and 4 lesions with advancing age. Subjects older than 50 years presented with grade 3 and 4 lesions in the SE sequence in 28.5% of the cases, in PS sequences in 40.7%, and in STIR sequences in 25%. In asymptomatic subjects, MRI shows an increasing prevalence of meniscal alterations which correlates with age. Especially in subjects older than 50 years, a significant number of meniscal tears must be expected. This shows the potential danger of the use of MRI alone as a basis for the determination of surgical intervention.     

Acute spinal cord injury. A study using physical examination and magnetic resonance imaging

Magnetic resonance imaging (MRI) was performed on 37 patients with acute spinal injury using T1- and T2-weighted images. Three different types of MRI signal patterns were detected in association with these spinal cord injuries. A classification was developed using these three patterns. Type I, seen in ten (27.0%) of the patients, demonstrated a decreased signal intensity consistent with acute intraspinal hemorrhage. Type II, seen in 16 (43.2%) of the patients, demonstrated a bright signal intensity consistent with acute cord edema. Type III, seen in three (8.1%) of the patients, demonstrated a mixed signal of hypointensity centrally and hyperintensity peripherally consistent with contusion. The remaining eight patients had normal cords by MRI. All 37 patients had an admitting neurologic assessment and classification of their spinal injury according to the Frankel classification and the Trauma Motor Index (TMI). At an average of 12.1 months postinjury, their neurologic function was reassessed. Patients with Type I patterns showed no improvement in their Frankel classification and minimal improvement in their TMI, 32.1 to 42.4. In comparison, all of the Type II and III patterns improved at least one Frankel classification. The Type II TMI increased from 70.8 to 91.9 and Type III from 37.3 to 75.7. This preliminary report indicates a distinct correlation between the pattern of spinal cord injury as identified by MRI and neurologic recovery. It appears that the ability of MRI to aid in examination of the condition of the spinal cord will offer a means of predicting neurologic recovery following acute spinal cord injury.     

Measuring hip development using magnetic resonance imaging

BACKGROUND: Abnormal hip development can have severe consequences if not detected and treated early. Previous studies have shown that if the abnormality is detected early, the outcome is good. Much is known about embryological hip development (weeks 1-10 after conception) from postmortem examination. For ethical reasons, information about hip development in the fetal stage of pregnancy (10 weeks to term) is less certain as it is largely gained from animal studies and from early radiograph studies. A few autopsy-based studies have been reported looking at hip development, but no one has shown, to our knowledge, that postmortem magnetic resonance is able to provide the same and possibly more information. The aim of this study was to assess the value of magnetic resonance imaging in providing information on fetal hip development. METHODS: Measurements of 30 patients (gestation, 17-42 weeks) were made regarding the width and depth of the acetabulum and the radius and diameter of the femoral head; volume and area were calculated. RESULTS: With the exception of the acetabular width, each dimension showed little development until week 20 when growth rose exponentially. The acetabular width showed a slow rate of growth, despite changes in the femoral head. Levels of observer agreement were high for all but depth (intraclass correlation coefficients, 0.90). CONCLUSIONS: The measurements were in line with previous postmortem studies. Magnetic resonance imaging is a valid alternative to postmortem in the assessment of hip development. Magnetic resonance imaging has the potential to alert clinicians to the possible abnormal development, allowing early intervention. STUDY DESIGN: Cross-sectional study with purposive sampling.     

颈椎间盘突出症的MRI表现及意义

探讨了１１８例颈椎间盘突出症的ＭＲＩ表现及异临床意义。在ＭＲＩ上，本病可分为中央型和侧方型。前者颈椎间盘从其后方中央部位突出，压迫颈髓前方，受压颈椎弯曲、变扁及向后移位；后者可见椎间盘从后外侧呈块状或碎片状突出，压迫颈髓前外侧，神经根向后外侧移位或消失。本组结果表明，ＭＲＩ可直接显示颈椎间盘突出症的部位、类型及颈髓和神经根的受损程度，为颈椎盘间突出症的诊断、鉴别诊断、治疗方法选择和预后判断提供可靠的方法。     

A longitudinal proton magnetic resonance spectroscopy study of mild traumatic brain injury

Despite the prevalence and impact of mild traumatic brain injury (mTBI), common clinical assessment methods for mTBI have insufficient sensitivity and specificity. Moreover, few researchers have attempted to document underlying changes in physiology as a function of recovery from mTBI. Proton magnetic resonance spectroscopy (1H-MRS) was used to assess neurometabolite concentrations in a supraventricular tissue slab in 30 individuals with semi-acute mTBI, and 30 sex-, age-, and education-matched controls. No significant group differences were evident on traditional measures of attention, memory, working memory, processing speed, and executive skills, though the mTBI group reported significantly more somatic, cognitive, and emotional symptoms. At a mean of 13 days post-injury, white matter concentrations of creatine (Cre) and phosphocreatine (PCre) and the combined glutamate-glutamine signal (Glx) were elevated in the mTBI group, while gray matter concentrations of Glx were reduced. Partial normalization of these three neurometabolites and N-acetyl aspartate occurred in the early days post-injury, during the semi-acute period of recovery. In addition, 17 mTBI patients (57%) returned for a follow-up evaluation (mean?=?120 days post-injury). A significant group?×?time interaction indicated recovery in the mTBI group for gray matter Glx, and trends toward recovery in white matter Cre and Glx. An estimate of premorbid intelligence predicted the magnitude of neurometabolite normalization over the follow-up interval for the mTBI group, indicating that biological factors underlying intelligence may also be associated with more rapid recovery.     

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the prediction of non-union consolidation

IntroductionNon-union perfusion can be visualized with dynamic contrast-enhanced (DCE) MRI. This study evaluated DCE-MRI to predict non-union consolidation after surgery and detect factors that affect bone healing.Materials and methodsBetween 2010 and 2015 non-union perfusion was prospectively quantified in 205 patients (mean age, 51.5 years, 129 men, 76 women) before intervention and at 6, 12, 26, 52 and more weeks follow-up. DCE-MRI results were related to the osseous consolidation, the ability to predict successful outcome was estimated by ROC analysis. The relevance of the body mass index (BMI) and the non-union severity score (NUSS) to the healing process was assessed.ResultsTibial (n = 99) and femoral (n = 76) non-unions were most common. Consolidation could be assessed in 169 patients, of these 103 (61%) showed eventual healing and demonstrated higher perfusion than in failed consolidation at 6 (p = 0.0226), 12 (p = 0.0252) and 26 (p = 0.0088) weeks follow-up. DCE-MRI at 26 weeks follow-up predicted non-union consolidation with a sensitivity of 75% and a specificity of 87% (false classification rate 19%). Higher BMI (p = 0.041) and NUSS (p < 0.0001) were associated with treatment failure.ConclusionsDCE-MRI perfusion analysis after non-union surgery predicts successful outcome and could facilitate the decision of early intervention. NUSS and BMI are important prognostic factors concerning consolidation.     

Detection of articular defects using magnetic resonance imaging: an experimental study

This study evaluates magnetic resonance imaging (MRI) in the detection of surgically created articular defects in bovine knees. A total of 26 articular defects was created in 2 fresh cadaveric cows' knees. The defects created include chondromalacic grade 2 defects, chondral and osteochondral defects from 3 to 15 mm in diameter. The knee joints were repaired in a normal saline bath to exclude air in the joint prior to MR scanning. T1 weighted spin echo (SE) images and 3D gradient echo (FISP 40 degrees 3D) images were obtained. The T1 weighted SE imaging technique detected 15 defects (57.7%) compared with FISP 3D imaging technique detection of 17 defects (65.4%). The two techniques combined enable 21 of 26 defects (80.8%) to be detected. The imaging techniques used in this study were not able to detect chondromalacic defects less than 10 mm in diameter, nor chondral defects less than 5 mm in diameter. However, small osteochondral defects of 3 mm in diameter are detectable provided the depth of the defect is not less than 10 mm. The FISP 3D imaging technique alone is more sensitive in detecting chondral defects. Both imaging techniques have similarly high sensitivities in detecting osteochondral defects. The imaging time for combined T1 weighted SE and FISP 3D sequence is short (16.5 mm) and this combined technique may be useful for MR scanning of knee joints suspected to have articular defects.     

Cricoid pressure displaces the esophagus: an observational study using magnetic resonance imaging

BACKGROUND: Cricoid pressure (CP) is often used during general anesthesia induction to prevent passive regurgitation of gastric contents. The authors used magnetic resonance imaging to determine the anatomic relationship between the esophagus and the cricoid cartilage ("cricoid") with and without CP. METHODS: Magnetic resonance images of the necks of 22 healthy volunteers were reviewed with and without CP. Esophageal and airway dimensions, distance between the midline of the vertebral body and the midline of the esophagus, and distance between the lateral border of the cricoid or vertebral body and the lateral border of the esophagus were measured. RESULTS: The esophagus was displaced laterally relative to the cricoid in 52.6% of necks without CP and 90.5% with CP. CP shifted the esophagus relative to its initial position to the left in 68.4% of subjects and to the right in 21.1% of subjects. Unopposed esophagus was seen in 47.4% of necks without CP and 71.4% with CP. Lateral laryngeal displacement and airway compression were demonstrated in 66.7% and 81.0% of necks, respectively, as a result of CP. CONCLUSION: In the absence of CP, the esophagus was lateral to the cricoid in more than 50% of the sample. CP further displaced both the esophagus and the larynx laterally.     

Evaluation of Gaucher disease using magnetic resonance imaging

Magnetic resonance imaging was used to study the skeletal involvement in a series of twenty-four patients with Gaucher disease. Many sites in the marrow of these patients were characterized by an abnormally low signal intensity that reflected shortened T1 and markedly shortened T2 values in the replaced marrow. The abnormality was non-homogeneous in distribution. In the lower extremity, the proximal (femoral) areas were more frequently affected than the distal (tibial) sites. The epiphyses were generally spared unless the involvement of bone was extensive. Lack of epiphyseal involvement on the magnetic resonance images generally precluded any suspicion of osteonecrosis. The extent of involvement, as suggested by the magnetic resonance data, appeared to correlate well with the occurrence of musculoskeletal complications. Magnetic resonance imaging is more sensitive than computerized tomography in demonstrating the extent of abnormalities in patients with Gaucher disease, and it may have prognostic value.     

Magnetic resonance imaging of acetabular labral tears

The acetabular labrum plays an important role in hip biomechanical function and stability. Labral tears can result in appreciable clinical symptoms and joint dysfunction and may predispose the hip to chondral damage and osteoarthritis. Magnetic resonance imaging is an effective tool for detecting and characterizing labral tears. Direct magnetic resonance arthrography is the most commonly used and validated technique for evaluating the labrum. However, indirect magnetic resonance arthrography and non-arthrographic magnetic resonance imaging are two less invasive and less resource-intensive techniques that should also be considered. Orthopaedic surgeons and radiologists should strive to develop and implement minimally and noninvasive diagnostic magnetic resonance imaging protocols for the investigation of labral pathology.