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Objective: The purpose of this study was to evaluate the incidence, cause, injury patterns, and MRI findings in knee dislocation in patients with normal and increased body mass index and to determine whether obesity interferes with knee MRI examinations., Materials and Methods: A retrospective study of the period from 2000 to 2007 (90 months) was performed at a level 1 trauma center, finding a total of 24 patients who had sustained a knee dislocation., Results: Twenty-two of the 24 patients underwent surgery and 19 patients had an MRI examination of diagnostic quality before surgery. Of the 24 patients, 11 had a body mass index greater than 25 and had knee dislocation due to low-energy trauma (nine due to a simple fall, two to a noncontact sport). Two of these 11 patients were morbidly obese (body mass index>40). These patients had no injuries to the popliteal tendon and they had no irreversible peroneal nerve injuries. Otherwise, the patients' injuries were in agreement with previous knee dislocation studies. Obesity did not interfere with knee MRI examinations. On the basis of the population served by our trauma center, the annual incidence of knee dislocation due to low-energy trauma in overweight patients is about 1.0 per million., Conclusion: The annual incidence in obese patients of knee dislocation due to low-energy trauma is not insignificant at a level 1 trauma center. As the prevalence of obesity increases, the injury patterns seen in emergency departments may change. The radiologist should be aware that even after a simple fall, overweight patients may have a knee dislocation.

Objective: The purpose of this study was to evaluate the prevalence, type, and location of meniscal injuries, particularly to assess the prevalence of unstable meniscal tears in acute knee trauma with tibial plateau fractures., Materials and Methods: A total of 78 menisci were evaluated in 39 patients who had undergone knee MDCT and MRI. Meniscal tears were classified as horizontal, vertical (subdivided into longitudinal and radial), flap, bucket-handle, or complex. The presence of meniscal contusion was documented. The anterior horn, body, and posterior horn were assessed separately for both menisci. Knee arthroscopy was performed on 28 patients., Results: Of the 39 patients in the study, 24 had detectable abnormal menisci, for a total of 33 abnormal menisci (42%). Among the 33 meniscal abnormalities were 11 longitudinal tears (33%), 17 contusions (52%), four flap tears (12%), six horizontal tears (18%), and six radial tears (18%). Among the 16 patients with meniscal tears (41% of the 39), 14 patients had an unstable tear. No significant correlation was found between degree of articular depression and site or morphologic features of the meniscal injury. Correspondingly, no statistical correlation was evident between normal menisci and degree of articular depression, nor was a significant correlation found between differing fracture groups and meniscal findings., Conclusion: A high percentage of patients (36%) with a tibial plateau fracture had an unstable meniscal tear. If a meniscal tear is detected preoperatively, meniscal surgery can be combined with fracture fixation, and reoperation can be avoided. A large number of meniscal contusions were found. Awareness of this abnormality can help radiologists increase specificity by avoiding false-positive findings of meniscal tear.

Objective: The objective was to study characteristic MRI findings in cervical spine fractures complicating ankylosing spondylitis (AS). Technical issues related to MRI are also addressed., Materials and Methods: A review of 6,774 consecutive cervical spine multidetector CT (MDCT) scans obtained during 6.2 years revealed 33 ankylosed spines studied for suspected acute cervical spine injury complicating AS. Of these, 20 patients also underwent MRI., Results: On MRI, of these 20 patients, 19 had a total of 29 cervical and upper thoracic spine fractures. Of 20 transverse fractures traversing both anterior and posterior columns, 7 were transdiskal and exhibited less bone marrow edema than did those traversing vertebral bodies. One Jefferson's, 1 atlas posterior arch (Jefferson's on MDCT), 2 odontoid process, and 5 non-contiguous spinous process fractures were detectable. MRI showed 2 fractures that were undetected by MDCT, and conversely, MDCT detected 6 fractures not seen on MRI; 16 patients had spinal cord findings ranging from impingement and contusion to complete transection., Conclusion: Magnetic resonance imaging can visualize unstable fractures of the cervical and upper thoracic spine. Paravertebral hemorrhages and any ligamentous injuries should alert radiologists to seek transverse fractures. Multiple fractures are common and often complicated by spinal cord injuries. Diagnostic images can be obtained with a flexible multipurpose coil if the use of standard spine array coil is impossible due to a rigid collar or excessive kyphosis.

Background: Magnetic resonance arthrography is a well-established diagnostic method in degenerative and traumatic disorders of the shoulder. Some radiologists prefer to apply a local anesthetic to the skin prior to performing the joint puncture. However, no information regarding the efficacy of local anesthetics exists., Purpose: To assess patient discomfort in arthrography injection., Material and Methods: A patient survey (n = 74) utilizing a visual analog scale (VAS) measured the intensity of pain in arthrography injection by those receiving local anesthetics (n = 36) versus those who did not (n = 38)., Results: Mean VAS scores were 20.8 (median 10.5, SD 24.3) for those receiving local anesthetics versus 19.3 (median 13.0, SD 20.7) for those who did not (P = 0.83, Mann-Whitney U test)., Conclusion: Routine use of local anesthesia of the skin in arthrography injection is unnecessary.

Purpose: To assess multidetector computed tomography (MDCT) findings in facial trauma in adults who accidentally fall from heights., Material and Methods: Of the MDCT scans of 2413 cases requested by emergency-room physicians for suspected facial injury, 155 (age 15.3-76.7, mean 42.0 years; 134 male, 21 female) met the criteria of falling from heights. These were reviewed by two researchers by consensus., Results: Of these 155, 118 (104 male, 14 female) had 247 fractures, while 37 had no fracture. The fractures were classified into 13 categories, the zygomatic complex being the region most frequently involved. Mean falling height, known in 132 of 155 cases, was 5.7 m (range 0.4-25) in all, 6.0 m (0.4-25) in those suffering a fracture, and 5.0 m (range 0.4-13) in those without a fracture. Patients with Le Fort II, Le Fort III, or frontal bone fractures had fallen higher and frequently had associated skull base fractures, but with considerable overlap in falling heights. Zygomatic arch and nasal bone fractures rarely occurred solitarily., Conclusion: In a fall-from-height injury, nasal bone and zygomatic arch fractures indicate the presence of more severe fractures. Height cannot solely predict injury probability. Clear sinus sign is a valuable aid in assessing midface trauma in falls from heights.

Purpose: To evaluate whether non-contrast multidetector computed tomography (MDCT) for suspected acute knee fractures can also be used to evaluate cruciate ligament pathology., Material and Methods: A total of 42 patients (17-65 years) underwent four-section MDCT. The images were independently evaluated at clinical workstations by four radiologists. They assessed the integrity (normal or torn) and the best slice direction (axial, sagittal, or coronal) for visualization of the cruciate ligaments. Magnetic resonance imaging (MRI), performed within 4 weeks (mean 6 days) in relation to MDCT, was considered the gold standard., Results: Ligament integrity at MDCT: the mean interobserver proportion of agreement for a normal anterior cruciate ligament (ACL) was 0.73, for a torn ACL 0.41, for a normal posterior cruciate ligament (PCL) 0.96, and for a torn PCL 0.54. Interobserver variation for ACL was significant (P = 0.0136-0.0260), but insignificant for PCL (P = 0.3389-0.7212). Intra-observer variation was insignificant. Visualization was best in the axial and sagittal direction for ACL and PCL, respectively. At MRI, 29 normal, one partially, and 12 completely torn ACLs, and 37 normal, four partially and one completely torn PCL were found., Conclusion: MDCT can detect an intact ACL and PCL with good specificity, accuracy, and negative predictive value. The assessment of torn ligaments is unreliable.

Objective: To analyze with conventional magnetic resonance imaging (MRI) the signal appearance of menisci repaired with bioabsorbable arrows., Design and Patients: Forty-four patients with 47 meniscal tears treated with bioabsorbable arrows underwent follow-up conventional MRI examination. The time interval between the surgery and MRI varied from 5 to 67 months (mean 26 months). Twenty-six patients also had concurrent repair of torn anterior cruciate ligament. The following grades were used to classify meniscal signal intensity: (a) G0; low signal intensity on all sequences and regular configuration in every plane, (b) G1; increased signal intensity within the meniscus, not extending to the meniscal surface, (c) G2; increased signal intensity linear in shape, which may or may not communicate with the capsular margin of the meniscus, without extending to the meniscal surface, and (d) G3; increased signal intensity extending to the meniscal surface., Results: Thirteen menisci (27.5%) had normal signal intensity, 13 menisci (27.5%) Grade 1 signal intensity, 9 menisci (19%) Grade 2 signal intensity and 12 menisci (26%) Grade 3 signal intensity. The time difference between operation and MRI was statistically significant between the G0 (36 months) and G3 groups (14 months; P = 0.0288). There was no statistical significance in different grades between medial and lateral meniscus or between patients with operated or intact ACL. On physical examination sixteen patients reported slight symptoms, seen evenly in each group., Conclusion: No difference was seen in different grades between patients with operated or intact ACL. The highest incidence of menisci with a Grade 3 signal was seen in patients where surgery was within the last 18 months.

The purpose of this study was to show the T(1rho) dispersion profile in various rat tissues (liver, brain, spleen, kidney, heart and skeletal muscle) at low (0.1 T) B(0) field at very low locking field B1, starting from 10 microT. The T(1rho) dispersion profile showed a quite similar pattern in all tissues. The highest R(1rho) relaxation rates were seen in the liver and muscle followed by the heart, whereas the values for spleen, kidney and brain were rather similar. The greatest difference between R2 relaxation rate and R(1rho) relaxation rate at B1=10 microT was seen in the liver and muscle. The steepest slope for a dispersion curve was seen in the muscle. The value of T(1rho) approximately approached the value of T2 when the locking field B1 approached 0. Except for the liver, the calculated apparent relaxation rate R2' was slightly larger than the calculated one. The potential value of T(1rho) imaging is to combine high R1 contrast of low-field imaging with the high signal-to-noise ratio (SNR) of high static field imaging. T(1rho) relaxation and dispersion data presented in the current study help to optimize the rotating-frame MR imaging.

This study was conducted to assess occurrence and distribution of burst fractures as well as common accident mechanisms and the associated neurologic deficit. Using picture archiving and communications system, all emergency multidetector computed tomography studies over 34 months were retrieved and evaluated for burst fractures by two radiologists by consensus. Initial neurological findings were retrieved from patients' medical records. One hundred fifty-two patients (112 male) with a total of 169 burst fractures were found. In both genders, the incidence of burst fractures peaked at the thoracolumbar junction and between levels T5 and T8. In 10% of cases, more than one burst fracture was seen, thereof 53% on noncontiguous levels. Main accident mechanisms were falls, traffic, and sports. Neurological deficit was highest in patients with burst fractures of the cervical spine, independent of accident mechanism, and lowest in thoracolumbar junction fractures. Burst fractures occur frequently in high energy traumas and are most commonly associated with falling and traffic accidents. Multiple burst fractures occur in 10% of cases, half thereof on noncontiguous levels.

Objective: To evaluate the outcome of a comprehensive neurorehabilitation program compared with that of conventional clinical care and rehabilitation for patients with traumatic brain injury (TBI)., Design: Nonrandomized, controlled trial with a 2-year follow-up., Setting: Nationwide rehabilitation center and level I trauma center, both in Finland., Participants: We studied 19 consecutive adults with a significant TBI who underwent a comprehensive neurorehabilitation program and 20 control patients who received conventional rehabilitation referred by physicians in the general health care system. The outcome of the control patients was not known before the selection. The groups were similar in age, sex, education, injury severity (assessed on the Glasgow Coma Scale, radiologic and neuropsychologic findings, neurosurgical interventions), time from the injury, and preinjury employment status., Interventions: A postacute, intensive, interdisciplinary, 6-week rehabilitation program for TBI patients who are considered to have adequate potential to achieve productivity by this means; focus on neuropsychologic rehabilitation and psychotherapy with vocational interventions and follow-up support., Main Outcome Measure: Status of productivity, judged as productive (defined as working, studying, or participating in volunteer activities) or nonproductive, evaluated on questionnaires filled in by patients and their significant others at the time of follow-up evaluation., Results: At follow-up, 89% of the treated patients were productive compared with 55% of the controls. The rehabilitation program was significantly predictive of the productive status at follow-up (odds ratio=6.96; 95% confidence interval, 1.26-38.44; P=.017). Other factors did not explain the better productivity of the treatment group. Two neuropsychologist-evaluators, who were blind to the rehabilitation history of patients and to each other's evaluations, were perfectly consistent in their classification of patients' productivity statuses., Conclusions: The findings support the proposition that comprehensive neuropsychologically oriented rehabilitation programs can improve psychosocial functioning in terms of productivity in postacute patients with moderate to severe TBI. Additional larger controlled studies are needed to establish the efficacy of TBI rehabilitation interventions.

Purpose: To evaluate the multidetector computed tomography (MDCT) findings of acute knee trauma and to compare radiography with MDCT in patients referred to a level 1 trauma center., Material and Methods: During a 5-year period, a total of 415 MDCT examinations were performed on 409 patients with acute knee trauma to reveal complex fracture anatomy or rule out a fracture. MDCT and primary radiographs were re-evaluated with respect to fracture location and trauma mechanism. Tibial plateau fractures were further analyzed depending on anatomical location: anterior-medial, anterior-lateral, posterior-lateral, and posterior-medial regions. Maximal depression of the tibial articular surface was measured. Findings on the primary knee radiographs were compared with MDCT findings., Results: Of the 409 patients, 356 (87%) had a knee fracture. A total of 451 fractures were found in all anatomic regions: distal femur (n=49), proximal tibia (n=307), patella (n=23), and proximal fibula (n=72). Primary radiographs were available in 316 (76%) cases. Of these, 225 (71%) had MDCT in order to reveal the fracture anatomy better, and 91 (29%) had a subsequent MDCT after negative plain radiographs. Overall sensitivity of radiography was 83%, while negative predictive value was 49%. On radiography, tibial plateau articular depression was underestimated in all regions except when the fracture consisted of the whole half of the anterior or posterior plateau. The three main injury mechanisms were traffic accident, a simple fall, and sport. In 49 cases (15%), primary radiographs were suboptimal due to positioning., Conclusion: In severely injured patients, diagnostically sufficient radiographs are difficult to obtain, and therefore a negative radiograph is not reliable in ruling out a fracture. In these patients, MDCT is a fast and accurate examination and is also recommended in patients with tibial plateau fractures or complex knee injuries in order to evaluate the fracture adequately.

Conventional radiography plays an essential diagnostic role in the primary evaluation of acute joint trauma. In complex fractures, however, computed tomography (CT) is an imaging modality often used second to radiography. As a result of technical breakthroughs in the field, multidetector CT (MDCT) allows faster imaging and better temporal, spatial, and contrast resolution compared with conventional single-slice spiral CT. MDCT with multiplanar reformation is helpful in disclosing fracture patterns, particularly in complex joint fractures, where they reveal occult fractures and show the exact number of fracture components and their degree of displacement.

The purpose of the study was to evaluate the diagnostic value of pelvic radiography in the initial trauma series when compared to multidetector CT (MDCT) findings in serious blunt trauma. Inclusion criteria were blunt trauma and pelvic radiography in the initial trauma series, followed by a whole-body MDCT. A total of 1386 patients (874 male, 512 female, age 16-91 years, mean 41 years) met the inclusion criteria. Imaging studies were evaluated retrospectively by anatomical region and classified, when possible, using the Tile classification. Based on MDCT, a total of 629 injuries occurred in 226 (16%) of these 1386 patients. Radiography depicted 405 fractures in these 226 patients, giving an overall sensitivity of 55%. In 24 patients (11%) radiography was false-negatively normal. The sensitivity of radiography was mainly good in the anteroinferior parts of the pelvis, fair in the acetabulum and ileum, and poor in the posterior ring. By MDCT 141 (62%) patients were classified using the Tile classification and by radiography 133 patients (59%) were classified. MDCT and radiography showed the same type of pelvic injury in 72 patients (59%) and the subtype in 17 patients (14%). In 48 patients (40%) the pelvis was shown to be stable by radiography but unstable by MDCT. In conclusion, the sensitivity of pelvic radiography is low, and it is not reliable for determining if the pelvic injury is stable or not.

Purpose: Using flexion/extension magnetic resonance imaging (MRI) with a dedicated positioning device, our purpose was to analyze pathologic cranio-vertebral joint anatomy and motion in patients with rheumatoid arthritis in comparison to normal patients, and to compare flexion/extension MRI with conventional radiographs (CRs) in patients with rheumatoid arthritis., Material and Methods: The 31 patients with rheumatoid arthritis and 20 healthy subjects included in the study were imaged in an open MRI scanner during flexion/extension. A dedicated positioning device was used. Additionally, we compared flexion/extension MRI with CRs in patients with rheumatoid arthritis. In MRI, the orientation and segmental motion of C0, C1, and C2 were assessed and structure of the dens and amount of pannus tissue were observed. Configuration of the cerebrospinal fluid space and the cord was evaluated in each position. In both MRI and CRs, anterior atlanto-axial subluxation and vertical dislocation were assessed and sagittal diameter of the dural sac was measured., Results: In the neutral position, C1 of the patients was oriented in a more flexed position in relation to both C0 and C2 compared to that in healthy subjects. The patients had more extension in the upper cervical spine than did healthy subjects. In flexion, atlantoaxial subluxation was greater in CRs than in MRI. In MRI, the amount of vertical dislocation did not depend on position. In the patients, there was considerably more cord impingement in flexion than in other positions., Conclusion: Evaluation of the rheumatoid cervical spine is optimized using MR images in the neutral, flexed, and extended positions. Measurements and relationships between structures should be compared in all positions. CRs with flexion-extension views are recommended as the first imaging method.

The purpose of this study was to describe the survival and volume of microneurovascular muscle flaps at different times after two-stage facial reanimation procedure by using magnetic resonance imaging (MRI) and to compare the functional outcome with MRI findings. Fifteen patients with a mean age of 36 years (range 7-63 years) operated on between 1988 and 1999 were available for this study. The muscles used for functional reconstruction were the latissimus dorsi (eight patients), gracilis (six patients) and serratus anterior (one patient). Hospital charts were reviewed and the clinical outcome of facial reanimation was graded on a scale from 1 to 6 according to House. The mean postoperative follow-up time was 7 years (range 3-14 years). Clinical grading and 1.5 T unit MRI of patients were performed concomitantly. The MR images were evaluated semi-quantitatively so that the muscle structure of the free flaps was graded on a scale from 1 to 4. The free flap area of each slice was defined and the volume of the free flap was calculated. Data were analysed statistically. The long-term functional outcome of the facial reanimation was regarded as good in 10 patients, which means they had only mild or moderate dysfunction of facial movements. In MR images, six free flaps displayed normal muscle structure, another six had a fatty appearance and two displayed severe muscle atrophy; in one patient the muscle tissue could not be identified. The volume of the free flap clearly declined in the course of the follow-up. A correlation was found between good functional outcome and normal muscle structure of the free flap in MRI, p = 0.020. The longer the follow-up time after muscle transplantation the poorer the functional result. A similar correlation was found between abnormal muscle structure in MRI and a long follow-up time. Magnetic resonance imaging can be used to assess the muscle structure of free microneurovascular flaps. Normal findings in MRI seem to correlate with a good clinical outcome in facial reanimation. A good functional result correlates with a shorter follow-up time and normal muscle structure in MRI.

The aim of this study was to assess the multi-detector computed tomography (MDCT) findings in acute shoulder traumas compared to radiographic findings in patients referred to a level one trauma center. Two hundred and ten patients (128 male, 82 female, age 16-95 years, mean age 51.7 years) underwent shoulder MDCT due to acute trauma. Three main mechanisms of injury were established: falling (113 patients, 54%), traffic accidents (36 patients, 17%) and falling from a height (12 patients, 6%). Based on MDCT, a total of 311 fractures--152 in the scapula and 159 in the proximal humerus--occurred in 191 (91%) of the 210 patients. The two most common occult fractures were lesser tubercle and coracoid process fractures. In 20 (63%) of the patients with a comminuted fracture of proximal humerus the exact number of fracture fragments was underestimated in radiographs. MDCT with multiplanar reconstructions (MPR) is a recommended complementary examination in patients with complex proximal humerus fractures where the extent of the fractures and the position or origin of dislocated fragments is not clear on radiography. This may increase the accuracy of the fracture classification and reveal occult fractures in other parts of the shoulder.

In type-II fractures of the odontoid process, the treatment is either conservative in a halo vest or primary surgical stabilisation. Since nonunion, requiring prolonged immobilisation or late surgery, is common in patients treated in a halo vest, the identification of those in whom this treatment is likely to fail is important. We reviewed the data of 69 patients with acute type-II fractures of the odontoid process treated in a halo vest. The mean follow-up was 12 months. Conservative treatment was successful, resulting in bony union in 32 (46%) patients. Anterior dislocation, gender and age were unrelated to nonunion. However, nonunion did correlate with a fracture gap (> 1 mm), posterior displacement (> 5 mm), delayed start of treatment (> 4 days) and posterior redisplacement (> 2 mm). We conclude that patients presenting with these risk factors are unlikely to achieve bony union by treatment in a halo vest. They deserve careful attention during the follow-up period and should also be considered as candidates for primary surgical stabilisation.

Purpose: To analyze multidetector computed tomography (MDCT) cervical spine findings in trauma patients with advanced ankylosing spondylitis (AS)., Material and Methods: Using PACS, 2282 cervical spine MDCT examinations requested by emergency room physicians were found during a period of 3 years. Of these patients, 18 (16 M, aged 41-87, mean 57 years) had advanced AS. Primary imaging included radiography in 12 and MRI in 11 patients., Results: MDCT detected one facet joint subluxation and 31 fractures in 17 patients: 14 transverse fractures, 8 spinous process fractures, 2 Jefferson's fractures, 1 type I and 2 type II odontoid process fractures, and 1 each: atlanto-occipital joint fracture and C2 laminar fracture plus isolated transverse process and facet joint fractures. Radiographs detected 48% and MRI 60% of the fractures. MRI detected all transverse and odontoid fractures, demonstrating spinal cord abnormalities in 72%., Conclusion: MDCT is superior to plain radiographs or MRI, showing significantly more injuries and yielding more information on fracture morphology. MRI is valuable, however, in evaluating the spinal cord and soft-tissue injuries. Fractures in advanced AS often show an abnormal orientation and are frequently associated with spinal cord injuries. In these patients, for any suspected cervical spine injuries, MDCT is therefore the imaging modality of choice.

Objective: The purpose of our study was to assess MDCT findings and the advantages of MDCT compared with radiography in patients referred to a level 1 trauma center for diagnostic evaluation of acute ankle and foot trauma., Materials and Methods: During a period of 37 months, 388 patients underwent MDCT of the ankle and foot due to an acute trauma. Imaging studies (MDCT and radiography) were retrospectively reevaluated with respect to fracture location, fracture type, and mechanism of injury, and findings from the primary radiographs of the ankle and foot were compared with MDCT findings., Results: Of the 388 patients, 344 (89%) had one or more fractures in the ankle or foot. A total of 517 fractures were found in all anatomic regions: ankle, calcaneus, talus, midfoot, and forefoot. The three most common occult fractures in the ankle not detected on primary radiography were isolated fractures of the posterior and medial malleolus and Tillaux fractures. The calcaneus was the most commonly fractured bone, and the sensitivity of radiography in the detection of calcaneal fractures was 87%. The sensitivity of radiography in the detection of talar fractures was 78%, whereas it was only 25-33% in the detection of midfoot fractures. A Lisfranc fracture-dislocation was not detected on primary radiography in five (24%) of 21 cases. The three main injury mechanisms were falling from a height (164 patients [48%]), a simple fall (68 patients [20%]), and a traffic accident (47 patients [14%])., Conclusion: In patients with injuries from high-energy polytrauma and in those with complex ankle and foot fractures, the sensitivity of radiography is only moderate to poor; in these cases, MDCT is recommended as the primary imaging technique.

Clinical symptoms of hyperparathyroidism are generally nausea, vomiting, fatigue, constipation, and hypotonicity of the muscles and ligaments; bone pain and tenderness are also seen but are more common in secondary hyperparathyroidism. We report a histologically confirmed case of a 28-year-old man whose sole symptom of primary hyperparathyroidism was lower extremity radicular pain due to a vertebral brown tumor. Magnetic resonance imaging demonstrated brown tumor to be hyperintense on T2-weighted and slightly hypointense on T1-weighted sequences; it showed intense contrast enhancement with gadolinium. Because brown tumors usually contain hemosiderin a short T2 should have been expected, but this was not seen in our case. Healing resulted in decreasing contrast enhancement on T1-weighted sequences and increasingly short T2. To our knowledge, this is the first report of a lumbar vertebral brown tumor associated with primary hyperparathyroidism.

Tactile sensory memory is needed to infer shape or motion from the spatiotemporal pattern of sensory input during manual exploration. Here we applied triplets of pressure pulses to the fingertips of subjects who were asked to respond when successive triplets were the same (COMPARE task) or when a particular stimulus was included in a triplet (CONTROL task). Stimulus sequences (30 s) alternated with rest blocks (30 s) and functional magnetic resonance images (fMRIs) were acquired in a 1.5-T scanner. During the COMPARE task, we found enhanced activation in inferior parietal cortex, supplementary motor area (SMA), and right dorsolateral prefrontal cortex (DLPFC). Activation of DLPFC is likely to be related to the attempt to memorize the stimulus sequences and activations of SMA and inferior parietal cortex to the analysis of temporospatial tactile patterns and, more generally, to guidance of haptic exploration. In addition, task-specific activation was seen in anterior cingulate gyrus, possibly related to the high mental effort required by the comparison task. Our rhythmic tactile stimulus as such, without any task-specific enhancement, activated also left cerebellum and (mainly left) putamen, supporting the idea that these structures are related to perception of temporal order of tactile stimuli.

The purpose of the present study was to assess incidence, fracture type, and location of spine fractures due to falls. All emergency room CT requests during a time period of 26 months were reviewed retrospectively. Patients who had fallen or jumped and were initially examined with multidetector CT (MDCT) were included. The MDCT studies were evaluated by two radiologists for trauma location, fracture type, and multiple level involvement. A total of 237 patients (184 males, 53 female, age range 16-86 years, mean age 42 years) met the inclusion criteria. A total of 203 vertebral fractures were seen in 127 patients. Burst fracture (n=78) was the most frequent type of trauma, usually located in the thoracolumbar junction (50%). Also, compression fracture (n=52) was most common in the thoracolumbar junction (39%). Posterior column fracture (n=52) was most frequently detected in the cervical spine (40%). Multiple-level spine fractures were seen in 41 (32%) of the injured patients, of which 12 (29%) had fractures at noncontinuous levels. With increasing height the overall incidence of fractures increased, and burst fractures and multiple level spine fractures became more frequent. Age had no effect on fracture type or location. Spine fractures due to falls are common. Burst fracture is the most common fracture type and most frequently seen in the thoracolumbar junction. Multiple-level fractures were seen in 32% of the cases, of which 29% were seen at noncontinuous levels. Serious spine fractures are seen in all falling height and age groups.

Purpose: To assess acute phase multidetector computed tomography (MDCT) findings in elbow traumas., Material and Methods: Fifty-six patients (32 M, 24 F, age 16 to 88 years, mean 44 years) underwent MDCT of the elbow due to an acute trauma during a time period of 34 months., Results: A total of 65 fractures and 3 main fracture types were established: 16 (25%) ulnar coronoid process fractures, 13 (20%) radial head fractures, and 12 (18%) humeral supracondylar fractures. Three main injury mechanisms were falling (38 (68%) patients), falling from high places (6 (11%) patients), and traffic accidents (5 (9%) patients). In 6 (11%) patients, MDCT revealed 13 occult fractures in the elbow joint compared to primary radiography. In four (7%) patients a displaced fracture fragment was detected in primary radiography, but the origin of the fragment was unclear. In all four cases, MDCT revealed the origin of the fragment., Conclusion: Radiography remains the primary imaging modality in elbow trauma, but in complex fracture patterns, where the extent of the fractures and the position or origin of dislocated fragments is not clear by radiography, the MDCT is a recommended complementary examination.

The aim of the study was to assess acute-phase multidetector CT (MDCT) findings in wrist injuries. We retrieved all emergency room MDCT requests processed in the period from August 2000 to May 2003. All patients with a wrist injury who underwent MDCT initially were included. Imaging studies were evaluated in relation to injury mechanism, fracture location, and fracture type. A total of 6422 MDCT examinations were performed during this 34-month period, and 38 patients (24 male, 14 female, age range 21-73 years, mean age 40 years) met the inclusion criteria. MDCT revealed 56 fractures and 7 dislocations in 29 patients. In 9 patients (24%) MDCT findings were normal. Eleven patients (29%) underwent surgical procedures. The main injury mechanism was a fall (58%). In 33 cases the primary radiograph was available. Compared to primary radiographs, MDCT revealed 9 occult fractures, mainly in small carpal bones. In 14 cases a suspected fracture (of the scaphoid in 7 cases) was ruled out by MDCT. Due to high-quality two-dimensional reformatting, MDCT examinations were not dependent on the wrist's position in the CT gantry. In the comparison with radiography, MDCT detected occult fractures and ruled out suspected fractures, both mainly in the small carpal bones. High-quality two-dimensional reformats gave significant information about the fracture anatomy. MDCT provides fast and valuable information in assessing complex wrist fractures or when the primary radiograph is equivocal.

A total of 35 flap reconstructions were done to cover exposed calcaneal bones in 31 patients. All patients had calcaneal fractures, 19 of which were primarily open. Soft tissue reconstruction for the closed fractures was indicated by a postoperative wound complication. A microvascular flap was used for reconstruction in 21 operations (gracilis, n = 11; anterolateral thigh, n = 5; rectus abdominis, n = 3; and latissimus dorsi, n = 2). A suralis neurocutaneous flap was used in eight, local muscle flaps in three, and local skin flaps in three cases. The mean follow-up time was 14 months (range 3 months-4 years). One suralis flap failed and was replaced by a latissimus dorsi flap. Necrosis of the edges that required revision affected three flaps. Deep infection developed in two patients and delayed wound healing in another four. During the follow-up the soft tissues healed in all patients and there were no signs of calcaneal osteitis. Flaps were considered too bulky in five patients. Soft tissues heal most rapidly with microvascular flaps. In the long term, gracilis muscle covered with free skin grafts gives a good contour to the foot. The suralis flap is reliable and gives a good final aesthetic outcome. Local muscles can be transposed for reconstruction in small defects.

The classification of odontoid process fractures introduced by Anderson and D'Alonzo in 1974 has gained wide acceptance among researchers and clinicians. In type II fractures the injury is located in the base of the odontoid process. In 1988 Hadley et al. introduced a comminuted subtype of this fracture, type IIA. Since then several authors have recommended a more aggressive surgical approach in treatment of this subtype. However, only a few cases of comminuted type II fractures have been reported. The objective of this study is to assess the occurrence of comminution in type II fractures. Twenty-six type II fractures imaged by multislice CT were reviewed. Subtle comminution of the fracture was observed in 12 of the cases. We conclude that, when imaged by multislice CT, subtle comminution in type II odontoid fractures is seen more commonly than previously reported in the literature.

Purpose: To assess acute phase multi-slice CT findings in horse-riding accidents in patients referred to a level one trauma center., Methods: Using PACS, we retrieved all CT requests during a time period of 19 months. Patients who had a horse-riding accident and were examined with multi-slice CT were included. The imaging findings of multi-slice CT were retrospectively evaluated by location and injury mechanism., Results: Forty-six patients (3 male, 43 female, age 16-55 years, mean age 30) were assessed. The injuries we found were five head, three facial, 13 spine, five body, two pelvic, and three lower extremity trauma. Multiple injuries were seen in five (11%) patients. In 21 patients (46%) the initial multi-slice CT examination(s) was normal. Three main injury mechanisms were established; falling off a horse (72%), a horse kick (11%), and crushing injury caused by a falling horse (13%). Fifteen (33%) patients had serious injuries, one lethal and they were associated more frequently with falling off a horse., Conclusion: Serious injuries with horse riding accidents are not uncommon. In two thirds of patients, the injury mechanism was falling off a horse. Multiple injuries were seen in 11% of cases. In the acute phase, multi-slice CT provided fast and valuable information in assessing these injuries.

The goal of the Image Guided Therapy Program, as the name implies, is to develop the use of imaging to guide minimally invasive therapy. The program combines interventional and intraoperative magnetic resonance imaging (MRI) with high-performance computing and novel therapeutic devices. In clinical practice the multidisciplinary program provides for the investigation of a wide range of interventional and surgical procedures. The Signa SP 0.5 T superconducting MRI system (GE Medical Systems, Milwaukee, WI) has a 56-cm-wide vertical gap, allowing access to the patient and permitting the execution of interactive MRI-guided procedures. This system is integrated with an optical tracking system and utilizes flexible surface coils and MRI-compatible displays to facilitate procedures. Images are obtained with routine pulse sequences. Nearly real-time imaging, with fast gradient-recalled echo sequences, may be acquired at a rate of one image every 1.5 s with interactive image plane selection. Since 1994, more than 800 of these procedures, including various percutaneous procedures and open surgeries, have been successfully performed at Brigham and Women's Hospital (Boston, MA).

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.

The purpose of this study was to demonstrate T1rho dispersion in different rat tissues (liver, brain, spleen, kidney, heart, and skeletal muscle), and to compare the 1/T1rho data to previous 1/T1 data and magnetization transfer of rat tissues at low (0.1 T) B0 field. The 1/T1rho dispersion showed a fairly similar pattern in all tissues. The highest 1/T1rho relaxation rates were seen in liver and muscle followed by heart, whereas the values for spleen, kidney, and brain were quite similar. Compared to 1/T2 relaxation rate, the greatest difference was seen in liver and muscle. The rank order 1/T1rho value at each locking field B1 was the same as the transfer rate of magnetization from the water to the macromolecular pool (Rwm) for liver, muscle, heart, and brain. The potential value T1rho imaging is to combine high T1 contrast of low field imaging with the high signal to noise ratio of high static field imaging. When the T1rho value for a given tissue is known, the contrast between different tissues can be optimized by adjusting the locking time TL. Further studies are encouraged to fully exploit this. Targets for more detailed research include brain infarct, brain and liver tumors.

The purpose of this study was to compare the sensitivity of different magnetic resonance imaging (MRI) sequences to depict periosteal edema in patients with medial tibial pain. Additionally, we evaluated the ability of dynamic contrast-enhanced imaging (DCES) to depict possible temporal alterations in muscular perfusion within compartments of the leg. Fifteen patients with medial tibial pain were examined with MRI. T1-, T2-weighted, proton density axial images and dynamic and static phase post-contrast images were compared in ability to depict periosteal edema. STIR was used in seven cases to depict bone marrow edema. Images were analyzed to detect signs of compartment edema. Region-of-interest measurements in compartments were performed during DCES and compared with controls. In detecting periosteal edema, post-contrast T1-weighted images were better than spin echo T2-weighted and proton density images or STIR images, but STIR depicted the bone marrow edema best. DCES best demonstrated the gradually enhancing periostitis. Four subjects with severe periosteal edema had visually detectable pathologic enhancement during DCES in the deep posterior compartment of the leg. Percentage enhancement in the deep posterior compartment of the leg was greater in patients than in controls. The fast enhancement phase in the deep posterior compartment began slightly slower in patients than in controls, but it continued longer. We believe that periosteal edema in bone stress reaction can cause impairment of venous flow in the deep posterior compartment. MRI can depict both these conditions. In patients with medial tibial pain, MR imaging protocol should include axial STIR images (to depict bone pathology) with T1-weighted axial pre and post-contrast images, and dynamic contrast enhanced imaging to show periosteal edema and abnormal contrast enhancement within a compartment.

The relationships of dynamic and static trunk muscle strength measurements and muscle geometry are studied. Physiologically, isometric muscle strength is directly related to muscle cross-sectional area. We measured isometric and isoinertial trunk muscle strength of 111 former elite male athletes, aged 45-68, by Isostation B-200. Paraspinal muscle cross-sectional areas were measured from axial magnetic resonance images at the L3-L4 level. Isometric and isoinertial torques were closely related, but angular velocities were not predicted by isometric maximal torque. The area of the psoas muscles correlated with isometric maximal flexion, as well as with isoinertial maximal torque. angular velocity, and power in flexion (r = 0.24-0.27). The area of the extensor group correlated with isometric maximal extension and with isoinertial maximal torque and power in extension (r = 0.24-0.25). We conclude that dynamic and static strength measurements are closely related, with angular velocity giving additional information on muscle function. Paraspinal muscle cross-sectional area is one determinant of isometric and isoinertial trunk muscle strength.

Objective: To investigate the feasibility of magnetic resonance imaging (MRI)-guided high power focused ultrasound (FUS) to perform synovectomy noninvasively., Methods: Five New Zealand white male rabbit knees with experimentally induced arthritis underwent MRI-guided thermal surgery by high power (60 W/10 s) sonication. Evidence of tissue coagulation was monitored during the procedure and confirmed by gross and microscopic evaluation and MRI., Results: Partial synovectomy was performed in five animals. Necrotized synovial tissue was observed on gross and microscopic evaluation. Visible signal intensity alterations including high signal intensity on T2-weighted (T2W) images and lack of contrast-enhancement on T1-weighted (T1W) post-contrast, post-sonication images were characteristic and reproducible., Conclusion: Our results demonstrate the ability of high power sonication to destroy synovial tissue in vivo.

Seventeen patients (18 knees) with a history of one or more patellar dislocations underwent Elmslie-Trillat (9 knees [group 1]) or Roux-Goldthwait (9 knees [group 2]) patellar realignment surgery. Anterior knee pain was evaluated with a questionnaire, and lateral patellar displacement and tilt were analyzed by magnetic resonance imaging both pre- and postoperatively. Postoperative evaluations were performed after 44 and 50 months (mean) in groups 1 and 2, respectively. The Elmslie-Trillat procedure provided better subjective relief of anterior knee pain and symptoms. One redislocation occurred in each group. Both procedures relieved excessive patellar lateralization, but the effect on patellar tilt was less marked. In patients who underwent the Roux-Goldthwait operation, a less pronounced correction of tilt and lateralization appeared to correlate with more satisfactory subjective results.

We used MRI to study a prospective series of 95 patients with inversion injuries of the ankle and no fracture on plain radiographs. We found an incidence of bone bruises of 27%, but these made no difference to the time of return to work, limitation of walking or physical activity, or the clinical outcome scores at three months. We conclude that bone bruises have very little clinical significance after inversion injuries of the ankle.

We report a case of a glomus tumor in the trachea which was an incidental finding in a 66-year-old man. The histological picture and immunohistochemical profile were typical for this tumor. The glomus tumor is an exceedingly rare mass lesion in the trachea, but it is useful to keep it among differential diagnostic alternatives when a tracheal tumor is seen on radiographs or endoscopy.

Purpose: To investigate magnetization transfer (MT) parameters and rotating frame relaxation time T1 rho in patellar cartilage at different levels of degeneration., Material and Methods: Thirty cadaveric patellae were examined at 0.1 T using the time-dependent saturation-transfer MT technique and the spin lock (SL) technique. In an SL experiment, nuclear spins are locked with a radiofrequency (RF) field, and the locked nuclear magnetization relaxes along the magnetic component of the locking RF field. The specimens were divided into three groups according to the level of cartilage degeneration. MT parameters and T1 rho were measured., Results: The MT effect was greater in degenerated cartilage than in normal cartilage. T1 rho was longer in advanced cartilage degeneration than in intermediate cartilage degeneration., Conclusion: The results suggest that more studies are needed to fully establish the value of SL imaging in cartilage degeneration.

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.

Purpose: To develop a superconducting magnetic resonance (MR) imager that provides direct access to the patient and permits interactive MR-guided interventional procedures., Materials and Methods: A 0.5-T superconducting magnet that allows a region of vertical access to the patient was designed and constructed. This magnet was integrated with newly designed shielded gradient coils, flexible surface coils, nonmagnetic displays, position-monitoring probes and device-tracking instrumentation., Results: The magnet homogeneity was 12.3 ppm or better, and the gradient field was linear to within 1% over an imaging region of 30 cm in diameter. The signal-to-noise ratio was 10% higher than in a comparable 0.5-T superconducting imager. Images were obtained in several anatomic regions with use of routine pulse sequences. Interactive image plane selection and near real-time imaging, with use of fast gradient-recalled echo sequences were demonstrated at a rate of one image every 1.5 s. More than 240 procedures (including open brain surgery) have been successfully performed within this environment., Conclusions: MR-guided interventional and surgical procedures can be performed with full patient access using an open-configuration, superconducting MR magnet with near real-time imaging and interactive image plane control.

Purpose: To report a very rare presentation of a stress fracture in a golfer: a stress fracture of the ulnar diaphysis., Case Summary: A 44-year-old woman had a 4-week history of a sore left wrist. She had been playing golf daily and had had no sudden trauma. Extensor tendinitis was suspected. Symptomatic treatment was given. Radiographs showed a spiculated periosteal reaction of the distal ulnar diaphysis with no signs of fracture or bone destruction. The suggestion of a malignant lesion was raised. Magnetic resonance imaging showed a healing ulnar fracture and edema of the interosseous membrane., Discussion: In golfers, stress fractures may be seen in ribs laterally and in tibias. We believe supination together with overuse of the hand flexor muscles caused the stress fracture presented, which has not previously been reported in golfers., Relevance: Physicians should be aware of the potential for ulnar stress fracture in golfers with wrist pain.

Magnetization transfer contrast (MTC) technique provides a new type of contrast in MR imaging. The MTC method is based on the interaction between the spins of free protons and those with restricted motion. Exercise-induced changes in signal intensity and MTC were measured in the forearm muscles of 10 volunteers at 0.1 T. There was 26% increase in signal intensity of active flexor muscles after exercise when imaged with ordinary gradient echo sequence. Despite this marked intensity increase, the postexercise values of MTC did not differ from the preexercise ones.

Patellofemoral relationships were analyzed in 11 patients (13 knees) with patellar dislocation and 15 asymptomatic subjects (15 knees) at 0 degree and 20 degrees of flexion. The measurements were made from five consecutive axial images through the patellofemoral joint. The six indices measured were lateral patellar tilt (LPT), lateral patellofemoral angle (LPA), lateral patellar displacement (LPD), patella-lateral condyle index (L/PW), congruence angle (CA), and sulcus angle (SA). The reproducibility of the method was evaluated. The difference between the two study groups was more evident at 0 degree than at 20 degrees of knee flexion. Significant differences were noted between measurements made at different levels of the joint, particularly in the controls. Isometric contraction of the quadriceps muscle lateralized and tilted the patella slightly in both groups. L/PW with and without quadriceps muscle contraction, and LPA with reference to the anterior condyles differentiated between the two study groups most clearly. LPT and LPA with reference to the anterior condyles differentiated the study groups better than LPT and LPA with reference to the posterior condyles. The reproducibility was good except for inter-observer comparison of CA and SA. The use of an imaging plane selected at the midpoint of the patellar articular cartilage increases the sensitivity of the measurements, since it takes into account both the height of the patella and the tendency towards lateralization. These results indicate that patellar tilt is best measured with the LPA index and patellar lateralization with the L/PW index at 0 degree knee flexion. This study should always include isometric contraction of the quadriceps muscle.

The time-dependent saturation transfer (TDST) method was applied at 0.1 T in order to evaluate the magnetization transfer contrast (MTC) of the patellar cartilage in vivo. Nine knees were examined. The MTC image of the knee is also demonstrated. The MTC of 63% of the patellar cartilage was attained. Magnetization transfer MR imaging may be of additional help in the evaluation of cartilage disorders at low-field MR imaging.

A new questionnaire was used to evaluate subjective symptoms and functional limitations in patellofemoral disorders. The questionnaire was completed independently by four groups of female subjects: controls (N = 17), and subjects with anterior knee pain (N = 16), patellar subluxation (N = 16), and patellar dislocation (N = 19). The questionnaire mean scores for the groups were 100, 83, 68, and 62 points, respectively (p < 0.0001). The items dealing with abnormal painful patellar movements (subluxations) (p < 0.0001), limp (p < 0.0001), pain (p < 0.0001), running (p < 0.0001), climbing stairs (p < 0.0001), and prolonged sitting with the knees flexed (p < 0.0001) differentiated the study groups most clearly. We recommend that these questions be asked when taking a standardized clinical history of an anterior knee pain patient. We also analyzed lateral patellar tilt and displacement by magnetic resonance imaging (MRI) in 28 subjects with patellar subluxation or dislocation. Low questionnaire sum score correlated best with increased lateral patellar tilt measured during quadriceps contraction in 0 degree knee flexion. It seems that a tendency to lateral patellar tilt during quadriceps contraction causes anterior knee pain and can be imaged in knee extension when the patella is not fully supported by femoral condyles.

The time-dependent saturation transfer technique was used to measure the transfer of magnetization in several rat tissues at 0.1 T. The length of the saturation pulse was varied from 0 to 510 msec. The magnetization transfer contrast effect was characteristic for each type of tissue. A substantial reduction of image intensity was obtained in skeletal muscle (74%), heart (71%), spleen (64%), brain (65%), pancreas (64%), liver (64%), kidneys (62%), and lungs (56%) with the longest saturation pulse available. Much smaller declines occurred in stagnant blood and peritoneal fat. The potential of this imaging technique for clinical conditions is discussed.

The correlation between the insertion level of the vastus medialis muscle and lateral patellofemoral angle (LPA), lateral patellar displacement (LPD) and tilt (LPT), and the height of the patella (LT/LP) was analyzed by magnetic resonance imaging (MRI) in patients with patellar dislocation (n = 10) and in control subjects (n = 10). Images were produced in 0 degrees and 20 degrees of knee flexion. The insertion level to the patella was also analyzed with the knee in extension. No significant correlation was noted between the insertion level and different patellofemoral indexes, but multiple-regression analysis showed that the best predictor for the insertion level was the LPA with the knee in extension. The insertion level was significantly more proximal in patients with patellar dislocations than in normal subjects.

Twenty patients with a chronic anterior cruciate ligament tear were studied. First they were interviewed on the preoperative history of unexpected giving way (pivot shift), then they were tested for clinical pivot shift sign, and last, the configuration of the lateral tibial plateau was studied using magnetic resonance imaging. A connection could be noticed between the history of instability symptoms and the pivot shift sign at clinical examination (P less than 0.001). Interestingly, there was also a link between the instability history and the configuration of the lateral tibial plateau (P = 0.0021), and, further, between the clinical pivot shift sign and the configuration of the lateral tibial plateau (P = 0.0002). The variation in the shape of the convexity of the lateral tibial plateau seems to be associated with the symptoms and prognosis of the patients with rupture of the anterior cruciate ligament.