Interventionalists take on new role in pain management.
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Analgesia↗
Biomedical subjects
J H Mink
Publications and source records attributed to J H Mink.
Magnetic resonance imaging evaluation of muscle usage associated with three exercises for rotator cuff rehabilitation.
PURPOSE: Methods of determining muscle usage for exercises involving rotator cuff muscles are limited. Therefore, this investigation used magnetic resonance imaging (MRI) to evaluate the effect of three different exercises used for rehabilitation of the rotator cuff. METHODS: Five normal volunteer subjects (3 men, 2 women, mean age 31.4 yr) were studied. The exercises were scaption with internal rotation (SIR), military press (MP), and side-lying 45 degrees abduction (SLA). MR imaging was performed immediately before and after exercise using a "fast" spin echo STIR sequence and oblique coronal plane imaging. Changes in signal intensity pre- and post-exercise were measured at comparable section locations for the MR images of the supraspinatus, infraspinatus, teres minor, subscapularis, deltoid, and trapezius. RESULTS: The SLA showed the greatest increase in signal intensity in all the muscles (percent change, P < 0.01) except for the trapezius, which was used more by the MP and SIR. None of the exercises activated the teres minor (percent change, P = not significant). CONCLUSION: These findings have important implications in efficacy of physical rehabilitation of the rotator cuff and avoidance of subacromial impingement exercise motions.
Adult↗
Spinal imaging and intervention: 1998.
Imaging of the lumbar spine is the most common application of magnetic resonance (MR) imaging in many radiologic practices. MR imaging has replaced computed tomography (CT) and CT myelography as the primary mode of spinal imaging and has relegated myelography to a secondary role in the evaluation of lumbar spinal disorders. At the same time, however, it has become evident that the correlation between gross anatomic findings as depicted on MR images and the clinical signs and symptoms detected by the clinician may be lacking. Defining the precise anatomic source of patients' complaints on the basis of imaging studies must be approached judiciously because a significant proportion of the population has disc disease as depicted on imaging studies, yet many have no clinical findings.
Disease Progression↗
Imaging of stress injuries to bone. Radiography, scintigraphy, and MR imaging.
Although conventional radiographs continue to be used as a primary method for the diagnosis of stress fractures, the limitations of radiography in early detection have been increasingly recognized. Advanced imaging techniques, including radionuclide methods, and more recently, MR imaging, have increasingly been employed in the assessment of stress fractures, and have provided valuable insights into the spectrum of stress-related changes to bone. This article reviews the diagnostic methods available to the clinician for detection of stress injuries to bone.
Bone and Bones↗
MR imaging of miscellaneous disorders of the shoulder.
During the course of routine MR imaging of the shoulder, a wide variety of abnormalities may be encountered owing to the technique's broad soft-tissue contrast resolution and multiplanar tomographic capability. In this article, the authors provide an overview of the lesions that might be encountered in this setting.
Adolescent↗
Percutaneous lumbar discectomy. Preoperative and postoperative magnetic resonance imaging.
We evaluated magnetic resonance imaging studies of thirty patients before and after a contained herniation of a lumbar disc was treated with a percutaneous lumbar discectomy. The imaging studies were evaluated to determine whether the preoperative appearance of the herniated disc was predictive of the outcome of percutaneous discectomy and also to determine a possible mechanism of action of the procedure in the relief of symptoms. The index operation was successful in seventeen (57 per cent) of the thirty patients. The preoperative imaging studies showed no differences in the appearance of the discs that went on to have a successful result and those that went on to have an unsuccessful result. Imaging studies made four to six weeks after the operation showed no measurable changes in the morphology of the disc. Imaging studies made a mean of fourteen months after the operation showed no changes in the morphology of the disc in twenty-four (80 per cent) of the patients, irrespective of the clinical outcome. Only three of the seventeen patients who had a successful result had a reduction of more than two millimeters in the size of the herniated segment, and two of the thirteen patients who had an unsuccessful result had an increase of more than one millimeter in the size of the herniated segment. We found that preoperative imaging studies cannot predict the clinical outcome of percutaneous lumbar discectomy.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Effect of a newly designed patellar realignment brace on patellofemoral relationships.
The effect of applying a newly developed patellar realignment brace to a patient with lateral subluxation of the patella was evaluated using active movement, loaded kinematic magnetic resonance (MR) imaging. The brace corrected the lateral displacement of the patella as shown on the kinematic MR imaging study. The patient underwent physical rehabilitation in conjunction with the use of the patellar realignment brace and has had resolution of her painful symptoms for the past 4 months.
Adult↗
Magnetic resonance imaging of muscle injuries.
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Acute Disease↗
Lumbar spine following successful surgical discectomy. Magnetic resonance imaging features and implications.
In an attempt to determine the expected long-term appearance of the lumbar spine in patients who have undergone successful lumbar discectomy, follow-up magnetic resonance (MR) examinations were performed on 23 patients (26 levels). All patients in the study had undergone at surgery at least one year prior to the study. All patients met rigorous criteria for a successful outcome. In nine cases, the postoperative study indicated a virtually total resolution of the previously identified disc herniations. In 13 cases, the study noted moderate, persistent posterior contour defects in the disc that contributed to persistent mass effect on the thecal sac or corresponding nerve root. In the remaining four cases, the postoperative study indicated virtually no change in the apparent contour of the posterior disc margin. Gadolinium contrast examinations demonstrated enhancement of the persistent contour abnormalities in 18 of 19 disc levels, suggesting the common presence of fibrosis, which was at times "mass-like," in these successful patients. These findings suggest that localized discal contour abnormalities morphologically simulating recurrent disc herniations and variably contributing to mass effect, may be commonly encountered in long-term follow-up imaging studies of successful discectomy patients.
Adult↗
Patellofemoral joint: identification of abnormalities with active-movement, "unloaded" versus "loaded" kinematic MR imaging techniques.
A positioning device was used to apply a "load" to stress the patellofemoral joint during active-movement, kinematic magnetic resonance (MR) imaging. Twenty-three symptomatic patellofemoral joints were studied by using "unloaded" versus "loaded" techniques. With the unloaded technique, seven joints were normal, nine had lateral subluxation, three had lateral tilt, and four had medial subluxation. With the loaded technique, one was normal, 13 had lateral subluxation, four had lateral tilt, and five had medial subluxation. The active-movement, loaded kinematic MR imaging technique provides improved ability to identify patellofemoral joint abnormalities.
Adolescent↗
Adverse reaction to intravenous gadoteridol.
Moderate and severe anaphylactoid reactions--while extremely rare--have been reported in association with intravenous administration of gadopentetate dimeglumine. There has been no similar experience related to use of the newly released magnetic resonance (MR) imaging contrast agent gadoteridol. The authors describe a case of vasovagal response and anaphylactoid reaction during intravenous administration of gadoteridol. MR users should be aware of the potential for adverse effects to occur in association with use of gadoteridol and be prepared by implementing appropriate observation procedures for patients receiving this as well as other MR contrast agents. In addition, physiologic monitoring devices and resuscitation equipment should be readily available in the clinical MR setting for proper treatment of patients who may experience moderate to severe adverse reactions.
Adult↗
Prior lateral patellar dislocation: MR imaging findings.
PURPOSE: To illustrate the constellation of magnetic resonance (MR) findings that suggest prior patellar dislocation. MATERIALS AND METHODS: A computer search of all MR examinations of the knee with a coded diagnosis of patellar dislocation performed between February 1988 and October 1990 disclosed 22 cases (11 male and 11 female patients, aged 1-70 years). RESULTS: Eighteen cases (82%) demonstrated hemarthrosis, medical retinacular disruption, and contusion of the lateral femoral condyle. In 11 cases, the patella was displaced from the trochlear sulcus, but in no patient was there complete dislocation at the time of imaging. Axial short-inversion-time inversion-recovery (STIR) images demonstrated subtle subchondral and cancellous signal intensity abnormalities that were often poorly appreciated on T2-weighted images. In 11 cases, patellar dislocation was not suspected before MR imaging. CONCLUSION: Hemarthrosis, medial patellar and lateral femoral contusion, and retinacular disruption suggest prior lateral patellar dislocation. Because of its sensitivity to subtle intraosseous signal abnormality, axial STIR imaging is a valuable adjunct in the evaluation of the acutely injured knee.
Contusions↗
Magnetic resonance imaging of miscellaneous disorders of the shoulder.
The ability to simultaneously and comprehensively evaluate both articular and extra-articular structures represents a distinct advantage for MR imaging over all other diagnostic methods. This article reviews how the technique can demonstrate a wide spectrum of abnormalities in and around the shoulder, with an emphasis on abnormalities encountered during MR imaging that were clinically unsuspected at the time of examination.
Humans↗
Kinematic MR imaging of the patellofemoral joint: comparison of passive positioning and active movement techniques.
Thirteen patients underwent magnetic resonance (MR) imaging of the patellofemoral joint in an evaluation of passive positioning and active movement kinematic MR imaging techniques. Sixteen joints were symptomatic, and 10 were not. Delineation of normal and abnormal patellar alignment and tracking was similar with the two techniques, but kinematic MR imaging performed with active movement allowed a substantial reduction in examination time while permitting evaluation of the contribution of associated activated muscles and soft-tissue structures to patellofemoral joint function.
Adolescent↗
Hematopoietic bone marrow hyperplasia: high prevalence on MR images of the knee in asymptomatic marathon runners.
In a prior study of marathon runners, we noticed that MR scans of the knee frequently showed hyperplasia of red (i.e., hematopoietic) bone marrow. Because the frequency of this finding in various populations is unknown, the purpose of this study was to determine the relative prevalences of hematopoietic bone marrow hyperplasia on MR examinations of the knees of healthy volunteers (n = 74), patients with symptoms of knee disorders (n = 54), and asymptomatic marathon runners (n = 23). The prevalence of hematopoietic bone marrow hyperplasia was 3% (2/74) for the healthy volunteers, 15% (8/54) for the patients, and 43% (10/23) for the marathon runners. The difference in prevalence between each of the three groups was statistically significant at p less than .05 in each case with hematopoietic bone marrow hyperplasia, the distal femur was the only area affected, while the epiphysis and proximal tibia were uninvolved. This pattern of affected bone marrow with hyperplasia of the hematopoietic marrow may be useful for the differential diagnosis. We postulate that the high prevalence of hematopoietic bone marrow hyperplasia in marathon runners may develop as a response to "sports anemia", which is commonly found in highly conditioned, aerobically trained athletes. Furthermore, this is considered to be a normal variant when found in the pattern described here.
Bone Marrow↗
The postoperative knee.
Magnetic resonance (MR) has established itself as the gold standard for noninvasive imaging of the knee. As in arthroscopy, assessment of injuries to the menisci, articular surfaces, synovium, and cruciate ligaments can be made. Additionally, MR has an advantage over arthroscopy in being able to assess the para articular soft tissues and cortical and medullary bony compartments. Until recently, the role of MR in the postoperative knee has been less clear. New information, however, suggests that MR is capable of assessing the status of the partially resected meniscus, the adjacent articular surfaces, and subchondral medullary lesions that frequently occur. There has been recent interest in reestablishment of the stabilizing function of a previously torn anterior cruciate ligament by means of autogenous or allogenous materials. MR permits the surgeon to assess the isometry and possible sites of graft impingement that may occur following cruciate ligament reconstruction. The purpose of this article is to define the current status of MR in the assessment of the postoperative knee.
Bone Transplantation↗
Knees of trained long-distance runners: MR imaging before and after competition.
A previous report indicated that recreational runners had increased meniscal signal intensity and visible joint effusions on magnetic resonance (MR) images after jogging. Therefore, the knees of trained long-distance runners were evaluated by means of MR imaging before and after competition to determine the presence of any structural alterations, particularly changes in intrameniscal signal intensity and/or joint effusions. T1-weighted coronal, proton-density and T2-weighted sagittal, and short T1 inversion recovery sagittal images were obtained in five trained runners 24 hours before and within 24 hours after completion of a long-distance race (distance range, 17-50 miles). Pre- and postrace images were filmed and windowed with standardized techniques. All ligaments were normal before and after the race. No alteration in meniscal signal intensity was noted for any menisci, and there was no increase in joint fluid after running. These data indicate that the knees of trained long-distance runners do not demonstrate changes similar to those found in recreational runners, suggesting that these athletes may have adapted to the stresses of their activity.
Adult↗
Exertional muscle injury: evaluation of concentric versus eccentric actions with serial MR imaging.
Eccentric muscular actions involve the forced lengthening or stretching of muscles and tend to produce exertional injuries. This study used magnetic resonance (MR) imaging to serially evaluate muscles in five healthy, untrained subjects who performed exhaustive biceps exercise by doing isolated eccentric and concentric actions with a dumbbell. Symptoms were assessed, and T2-weighted images of the arms were obtained before exercise and 1, 3, 5, 10, 25, 40, 50, 60, and 80 days after exercise. Statistically significant increases in T2 relaxation times indicative of muscle injury occurred on each day of MR imaging evaluation in muscles performing eccentric actions, peaking on day 3 in two subjects; day 5, two subjects; and day 10, one subject. The pattern and extent of the abnormalities on MR images were variable. Pain, soreness, and joint stiffness were present on days 1, 3, and 5 in muscles that performed eccentric actions. MR imaging showed subclinical abnormalities that lasted as long as 75 days after the disappearance of symptoms (two subjects). Muscles that performed concentric actions had no changes in T2 relaxation times and were asymptomatic throughout the study.
Adult↗