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Biomedical subjects

W B Morrison

Publications and source records attributed to W B Morrison.

At least 19 recordsLinked to original sources
PubMed2007

MRI of rupture of the spring ligament complex with talo-cuboid impaction.

The spring ligament complex is essential for the stability of the longitudinal arch of the foot and includes the ligaments between the calcaneus and the talus at the superomedial to inferoplantar aspect of the foot. Tears of the spring ligament complex are most commonly degenerative in etiology and secondary to concomitant abnormality of the posterior tibial tendon. We report MRI findings in a 30-year-old man who presented with traumatic rupture of the spring ligament complex, seen following dislocation of the talonavicular joint. We also describe the previously unreported MRI features of talo-cuboid impaction secondary to disruption of the spring ligament complex.

Accidental Falls↗
PubMed2006

Use of a novel percutaneous biopsy localization device: initial musculoskeletal experience.

OBJECTIVE: To preliminarily evaluate a new CT-biopsy guidance device, the SeeStar (Radi, Uppsala, Sweden), for use in musculoskeletal applications. DESIGN: The device was evaluated using an imaging phantom and in various simulated clinical biopsy situations. The phantom study was undertaken to optimize the linear metallic artifacts produced by the guidance device. The phantom and guidance device were imaged with CT after altering different imaging parameters, including field of view, filter, focal spot size, kV, mAs, slice thickness and pitch. Clinical biopsy situations were simulated for a superficial biopsy, a deep biopsy and a horizontal biopsy approach. RESULTS: Altering CT parameters had little effect on the subjective appearance of the linear metal artifact, which is used to plan the biopsy approach. Placement of an 18-G needle inside of the biopsy device was subjectively helpful in exaggerating the artifact. Use of this artifact could be helpful in planning biopsy approach for deep lesions or lesions near critical structures. The metal guide on the device adequately supports a standard biopsy needle, making it potentially advantageous for biopsy of superficial lesions and lesions approached from a horizontal orientation. CONCLUSION: Use of this CT-biopsy guidance device is potentially useful for musculoskeletal applications. The linear metal artifact produced by the device can help plan the biopsy approach. The device can also be useful in biopsy situations where the biopsy needle requires external support during imaging.

Artifacts↗
PubMed2006

MRI of bone marrow edema-like signal in the pathogenesis of subchondral cysts.

OBJECTIVE: To determine if a relationship exists between bone marrow edema-like signal and subchondral cysts on magnetic resonance imaging (MRI). DESIGN: Retrospective cohort of 32 patients with two sequential knee MRI. Patients with acute trauma, infection, neoplasm, or osteonecrosis were excluded. The degree of osteoarthritis was assessed using an adaptation of the Baltimore Longitudinal Study of Aging (BLSA) scale. Initial and follow-up exams were reviewed for presence, location, size and changes of marrow edema-like signal, subarticular cysts and cartilage abnormality. All locations in the knee were aggregated for analysis with descriptive statistics. RESULTS: The mean time interval between exams was 17.52 months (range 2.1-40.1 months). There were 23 cysts: 11 (47.8%) new, 6 (26.1%) increased size, 1 (4.4%) decreased size, and 5 (21.7%) no change in pre-existing lesions. Cysts always arose from regions of marrow edema-like signal. There were 68 subarticular areas of marrow edema-like signal: 16 (23.5%) new, 23 (33.8%) increased size, 17 (25%) decreased size, 11 (16.2%) resolved and 1 (1.5%) no change in pre-existing lesion. Marrow edema-like signal size always changed with cyst development: increased in 6/11 (54.5%), decreased in 2/11 (18.1%) and resolved in 3/11 (27.2%). Change in cyst size was always accompanied by a change in edema-like signal size. An MRI visible cartilage abnormality was adjacent to 87% (20/23) of cysts. The mean BLSA score changed from 2.6 to 3.6 indicating an overall progression of osteoarthritis. CONCLUSION: Subchondral cysts develop in pre-existing regions of subchondral bone marrow edema-like signal.

Adult↗
PubMed2005

Cartilage anlagen adapt in response to static deformation.

Connective tissue adaptation, including the development of cartilaginous anlagen into bones, is widely believed to be related to dynamic, intermittent load and stress histories. Static stresses, on the other hand, are generally believed deleterious in tissue adaptation. Using serial MRI in a natural human experiment (manipulation and corrective casting of infant clubfoot), we have observed casting produces two effects: (1) the well recognized change in relative positions of the hindfoot anlagen; (2) a newly recognized immediate shape change in the anlagen. These changes seemingly enhance the rate of growth of the anlagen and of the ossific nucleus. The shape change or deformation in the anlagen would occur as a result of alterations in the magnitudes and directions of loading from soft tissue attachments and muscle activity and would necessarily be associated with changes in the stress states within the anlagen and, when present, the ossific nuclei. Given the known role of load and stress history in tissue adaptation, we presume the reduced stress histories influence the enhanced growth rates. These observations contradict some current theories of tissue adaptation since static, rather than dynamic stresses play a crucial role in accelerating the growth and development of anlagen in the infant clubfoot.

Biomechanical Phenomena↗
PubMed2005

Assessment of bone biopsy needles for sample size, specimen quality and ease of use.

OBJECTIVE: To assess whether there are significant differences in ease of use and quality of samples among several bone biopsy needles currently available. DESIGN: Eight commonly used, commercially available bone biopsy needles of different gauges were evaluated. Each needle was used to obtain five consecutive samples from a lamb lumbar pedicle. Subjective assessment of ease of needle use, ease of sample removal from the needle and sample quality, before and after fixation, was graded on a 5-point scale. The number of attempts necessary to reach a 1 cm depth was recorded. Each biopsy specimen was measured in the gross state and after fixation. RESULTS: The RADI Bonopty 15 g and Kendall Monoject J-type 11 g needles were rated the easiest to use, while the Parallax Core-Assure 11 g and the Bard Ostycut 16 g were rated the most difficult. Parallax Core-Assure and Kendall Monoject needles had the highest quality specimen in the gross state; Cook Elson/Ackerman 14 g and Bard Ostycut 16 g needles yielded the lowest. The MD Tech without Trap-Lok 11 g needle had the highest quality core after fixation, while the Bard Ostycut 16 g had the lowest. There was a significant difference in pre-fixation sample length between needles (P<0.0001), despite acquiring all cores to a standard 1 cm depth. Core length and width decrease in size by an average of 28% and 42% after fixation. CONCLUSION: Bone biopsy needles vary significantly in performance. Detailed knowledge of the strengths and weaknesses of different needles is important to make an appropriate selection for each individual's practice.

Analysis of Variance↗
PubMed2001

Noncontrast MR imaging and MR arthrography of the ulnar collateral ligament of the elbow: prospective evaluation of two-dimensional pulse sequences for detection of complete tears.

OBJECTIVE: To compare MR imaging techniques with differing contrast and spatial resolution for evaluation of complete disruption of the ulnar collateral ligament (UCL) anterior bundle in a cadaveric elbow model. DESIGN: Complete UCL tears were surgically created at the typical location for clinical tears in eight of 28 fresh frozen cadaveric elbow specimens. All specimens underwent 1.5 T MR imaging in the oblique coronal plane, using an extremity coil. The sequences employed were: T1-weighted spin echo (T1 SE), proton density-weighted (PD) fast spin echo (FSE), fat-suppressed T2-weighted FSE (T2 FSE), gradient recalled echo (GRE) with a high matrix, PD FSE with a high matrix (HRPD), and fat suppressed T1-weighted SE with intra-articular gadolinium (MRAr). Two radiologists independently graded the UCL with separate and side-by-side assessments. RESULTS: Sensitivity/specificity pairs were as follows for reader A and reader B, respectively: T1 SE: 0.25/0.95, 0.50/0.95; PD FSE: 0.38/1.00, 0.25/1.00; T2 FSE: 0.50/0.95, 0.63/0.95; GRE: 0.63/0.85, 0.63/0.60; MRAr: 0.88/1.00, 1.00/0.80; HRPD: 0.50/1.00, 0.88/0.80. Kappa statistics for measuring interobserver reliability for each sequence were poor under T1 SE (-0.13) and GRE (0.19), moderate under HRPD (0.41) and T2 FSE (0.44) and good under MRAr (0.62) and PD FSE (0.78). For both readers, the rating for overall image quality was highest for HRPD, and the rating for UCL lesion conspicuity was the highest for MRAr. CONCLUSIONS: Of the MR imaging pulse sequences tested, MRAr showed the greatest ability to identify complete ligamentous injuries with good agreement between readers and had the highest subjective preference for lesion conspicuity. However, HRPD had the least interobserver variability and the highest subjective preference for overall image quality.

Aged↗
PubMed2001

MRI of the foot and ankle: prevalence and distribution of occult and palpable ganglia.

The purpose of this study was to evaluate the prevalence and anatomic distribution of occult and palpable ganglia of the foot and ankle as seen by MRI. Within a 7-year period MRI of the ankle was performed on 2813 patients, and MRI of the foot on 2277 patients using a 1.5T magnet. In all, 167 ganglia in 155 patients were detected. MR images of these patients were reviewed retrospectively by two observers with regard to prevalence, imaging characteristics, and exact anatomic location of ganglia. Clinical findings and (when available) surgical reports were also reviewed. One hundred fifty-seven ganglia in 145 patients were present on MR images of the ankle, and 10 ganglia in 10 patients on MR images of the foot, resulting in a prevalence of 5.6% (157/2813) in the ankle, and a prevalence of 0.4% (10/2277) in the foot. The most common location was the tarsal sinus or tarsal canal (57/167 ganglia [34.1%]). However, only four of these (7%) were palpable as a soft-tissue mass. The second most common location was around the Lisfranc joint (23/167 [13.8%]), of which 11/23 [47.8%] were clinically palpable. Palpable ganglia were statistically larger in size than occult ganglia measured in any of three diameters (P = 0.01-0.002). In addition, ganglia of the foot and ankle represented 42% of all clinically suspected soft-tissue masses. Ganglia in the foot and ankle are an infrequent finding on routine MRI of the foot and ankle. When they occur, these ganglia are most frequently located in the tarsal sinus and tarsal canal, where they are occult to clinical palpation. If ganglia are clinically palpable, they are most commonly located around the Lisfranc joint. In addition, palpable ganglia are larger than occult ganglia.

Adolescent↗
PubMed2001

Autogenous osteochondral "plug" transfer for the treatment of focal chondral defects: postoperative MR appearance with clinical correlation.

OBJECTIVE: To describe the MR appearance following autogenous osteochondral "plug" transfer for the treatment of focal chondral defects of the knee. DESIGN AND PATIENTS: Twenty-nine 1.5-T MR knee studies including dynamic gadolinium enhancement were performed on 21 patients following autogenous osteochondral "plug" transfer. Three musculoskeletal radiologists retrospectively reviewed images to evaluate graft and donor site appearance and MR findings were correlated with clinical outcomes. RESULTS: MR images demonstrated graft protuberance (n=12/21; range 1-2 mm), depression (n=2/21; range 1 mm), and surface incongruity: mild (n=17/21), moderate (n=2/21), marked (n=1/21). The T2 signal of graft cartilage was similar to that of adjacent cartilage in 25 of 29 examinations, and increased in four. Graft cartilage thickness relative to adjacent cartilage was <50% in six patients, 50-100% in 15. Graft enhancement in bone was absent at 2 weeks, but present at between 4 and 6 weeks following surgery. All patients had clinical follow-up examinations and knee outcome survey scores were obtained in 15 patients with follow-up greater than 3 months after surgery. All patients demonstrated the expected short-term progressive clinical improvement. CONCLUSION: MR images reveal a wide range of appearances following osteochondral "plug" transfer. Minor variations in graft orientation and surface congruity do not result in adverse clinical outcome in the short term.

Adult↗
PubMed2001

Magnetic resonance imaging at different time periods following hamstring harvest for anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to evaluate the magnetic resonance imaging (MRI) appearance of the hamstring graft harvest site after harvesting the hamstring tendons to reconstruct a torn anterior cruciate ligament (ACL). TYPE OF STUDY: Case series. METHODS: We performed MRI on 21 patients who had previously undergone hamstring harvest and ACL reconstruction. Twenty of the patients (7 female and 13 male; mean age, 37 years; range, 16 to 84 years), all volunteers, were selected from a series of 45 ACL reconstructions performed by the senior author during a 20-month period. Another patient, a 32-year-old man, underwent ACL reconstruction elsewhere 32 months before. Both the semitendinosus and gracilis tendons were harvested in all cases. All MRIs were obtained on a 1.5-T magnet and were prospectively evaluated by 2 experienced musculoskeletal radiologists who were blinded to the time interval between graft harvest and MRI. RESULTS: Two weeks after graft harvest, MRI showed ill-defined intermediate signal on T1-weighted images and increased signal on T2-weighted images, consistent with fluid in the harvest site, with no discernable tendon. At 6 weeks, structures were seen at the level of the superior pole of the patella that had morphology and signal characteristics similar to native tendon. By 3 months, structures with normal morphology and signal characteristics were seen to the level of the joint line, and by 12 months, to the level of 1 to 3 cm above that of the tibial attachment. At 32 months, the tendons appeared on MRI to normalize to a level of 1 to 2 cm above their tibial attachment. CONCLUSION: Following hamstring tendon harvest, MRI demonstrates an apparent regeneration of tendons beginning proximally and extending distally over time.

Adolescent↗
PubMed2001

Indirect MR arthrography of the knee: effects of low-intensity ultrasound on the diffusion rate of intravenously administered Gd-DTPA in healthy volunteers.

RATIONALE AND OBJECTIVES: To evaluate whether application of low-intensity ultrasound may increase the diffusion rate of intravenously administered gadopentetate dimeglumine (Gd-DTPA) and increase the amount of joint fluid on indirect magnetic resonance (MR) arthrography. METHODS: Conventional MR imaging, indirect MR arthrography, and power Doppler ultrasonography were performed before and after application of therapeutic, pulsed low-intensity ultrasound in 12 asymptomatic knees of 12 volunteers. Intra-articular diffusion of intravenously administered Gd-DTPA as measured by signal intensity differences of the intra-articular joint fluid before and after ultrasound treatment was assessed. In addition, the amount of joint fluid was rated, and differences in synovial blood flow as evidenced by power Doppler ultrasonography were noted. RESULTS: All volunteers tolerated well the application of therapeutic low-intensity ultrasound. A significant increase in intra-articular diffusion of intravenously administered Gd-DTPA was noted in all knees, and an increase in joint fluid was noted in 8 of 12 knees (66.6%). Detection of power Doppler flow signal in the synovium of the suprapatellar recess was possible in one instance at posttreatment exam. CONCLUSIONS: Use of pulsed, therapeutic low-intensity ultrasound may increase the diffusion rate of intravenously administered Gd-DTPA and may induce joint effusion.

Adult↗
PubMed2001

MR imaging of the posterior cruciate ligament graft: initial experience in 15 patients with clinical correlation.

PURPOSE: To describe the magnetic resonance (MR) appearance of the posterior cruciate ligament (PCL) graft in the 1st postoperative year and to correlate the MR findings with clinical examination findings. MATERIALS AND METHODS: Nineteen MR examinations were performed in 15 patients (with 15 grafts) 1-33 months after PCL reconstruction. Results of clinical follow-up were available in 14 patients. Graft shape and thickness were recorded, and intrasubstance signal intensity at T2-weighted imaging was graded. The MR findings were correlated with the time between surgery and clinical examination. RESULTS: At MR imaging, 13 grafts appeared intact, one could not be assessed owing to hardware artifact, and one initially appeared disrupted. Graft thickness was 7-19 mm. There was no significant difference between graft thickness versus time since surgery and signal intensity versus time since surgery (P =.14). In two of three patients who underwent sequential MR examinations, graft thickness and intrasubstance signal intensity decreased as the time between reconstruction and MR imaging increased. Two of 14 patients who underwent physical examination had a posterior drawer, and one also had an anterior cruciate ligament graft tear. Both patients with knee instability demonstrated intact PCL graft fibers at MR imaging. There was no correlation between knee stability and graft thickness, signal intensity, or shape. CONCLUSION: After PCL reconstruction, MR imaging in the 1st year depicts a thickened graft with increased signal intensity. There does not appear to be a relationship between clinical stability and findings at MR imaging.

Adolescent↗
PubMed2001

Lateral ulnar collateral ligament of the elbow: optimization of evaluation with two-dimensional MR imaging.

PURPOSE: To compare, in a cadaveric model, magnetic resonance (MR) imaging techniques with differing contrast and spatial resolution properties in the evaluation of disruption of the lateral ulnar collateral ligament (LUCL) at the elbow. MATERIALS AND METHODS: LUCL tears were surgically created in eight of 28 cadaveric elbow specimens. All specimens underwent 1.5-T MR imaging with the following pulse sequences: T1-weighted spin echo (SE), intermediate-weighted fast SE, fat-suppressed T2-weighted fast SE, gradient-recalled echo (GRE) with high spatial resolution, intermediate-weighted fast SE with high spatial resolution, and fat-suppressed T1-weighted SE with intraarticular administration of gadopentetate dimeglumine (MR arthrography). All images were obtained in the oblique coronal plane. Two radiologists independently graded the LUCL with separate and side-by-side assessment. RESULTS: Areas under the receiver operating characteristic curve were as follows for readers A and B, respectively: T1-weighted SE imaging, 0.64 and 0.62; intermediate-weighted fast SE imaging, 0.87 and 0.67; T2-weighted fast SE imaging, 0.68 and 0.69; GRE imaging, 0.56 and 0.68; MR arthrography, 0.84 and 0.85; and intermediate-weighted imaging with high spatial resolution, 0.92 and 0.88. Interobserver reliability was poor with T1-weighted SE imaging (kappa = 0.13) and GRE imaging (kappa = 0.18), fair with T2-weighted fast SE imaging (kappa = 0.36), and moderate with MR arthrography (kappa = 0.46), intermediate-weighted fast SE imaging (kappa = 0.55), and intermediate-weighted imaging with high spatial resolution (kappa = 0.59). CONCLUSION: Intermediate-weighted imaging with high spatial resolution and MR arthrography showed the greatest overall ability to enable the diagnosis of LUCL tears.

Aged↗
PubMed2001

Subtendinous bone marrow edema patterns on MR images of the ankle: association with symptoms and tendinopathy.

OBJECTIVE: We sought to describe a pattern of subtendinous bone marrow edema on MR images of the ankle and to determine if there is an association with location of symptoms and overlying tendinopathy. MATERIALS AND METHODS: At 1.5 T, 141 MR examinations of the ankle (116 clinical examinations of patients with chronic pain, 25 of asymptomatic control patients) were performed using T1-weighted, proton density-weighted fast spin-echo, and T2-weighted fat-suppressed fast spin-echo sequences. Images were retrospectively reviewed by two musculoskeletal radiologists for presence of bone marrow edema occurring in a subcortical location associated with the course of the medial or lateral tendon groups, as well as focal thickening or increased T2 signal within the tendons. These findings were correlated with clinical information regarding symptom location. The association of subtendinous marrow edema with tendinopathy and symptom location was statistically analyzed. RESULTS: Subtendinous bone marrow edema was present at 26 sites on 24 ankle MR examinations (17%) (at the medial malleolus [n = 17] associated with the posterior tibialis tendon, at the lateral malleolus [n = 6] and the calcaneus [n = 2] associated with the peroneus longus and brevis tendons, and at the cuboid [n = 1] associated with the peroneus longus tendon). These subtendinous bone marrow edema patterns were significantly associated with overlying tendon abnormality medially (p = 0.001) and laterally (p = 0.001), and with symptoms medially (p = 0.0016) but not laterally (p = 0.078). CONCLUSION: On MR images of the ankle, bone marrow edema localized in a subtendinous location is associated with overlying tendinopathy medially and laterally and with ankle pain medially.

Adult↗
PubMed2001

MR imaging of meniscal cysts: incidence, location, and clinical significance.

OBJECTIVE: The purpose of this study was to determine the incidence of medial versus lateral meniscal cysts as seen on MR imaging. MATERIALS AND METHODS: A total of 2572 knee MR imaging reports were retrospectively reviewed for the presence of meniscal tears and cysts. Two musculoskeletal radiologists reviewed all images with reported cysts. The type and location of meniscal tear and the presence and location of meniscal cysts were recorded. RESULTS: A total of 1402 meniscal tears were reported in 2572 MR examinations (922 [66%] of 1402 in the medial compartment; 480 [34%] of 1402 in the lateral compartment). Meniscal cysts were present in 109 (4%) of 2572 knees. Of the 109 cysts, 72 (66%) were in the medial compartment, and 37 (34%) were in the lateral compartment. Meniscal cysts were found in association with 72 (7.8%) of the 922 medial meniscal tears and 37 (7.7%) of the 480 lateral meniscal tears. Meniscal cysts showed direct contact with an adjacent meniscal tear in 107 (98%) of 109 cases, with the tear showing a horizontal component in 96 (90%) of 107 cases. CONCLUSION: Meniscal cysts occur almost twice as often in the medial compartment as in the lateral compartment. Medial and lateral tears occur with the same frequency. These findings, when viewed in the context of the historical literature on meniscal cysts, suggest that MR imaging detects a greater number of medial meniscal cysts than physical examination or arthroscopy, and that MR imaging can have an important impact on surgical treatment of patients.

Adult↗
PubMed2001

MR imaging of the diabetic foot.

Diabetes is a common disease with potentially devastating complications affecting the foot and ankle. A combination of vascular disease, peripheral neuropathy, and immunopathy result in a cascade of conditions including ischemia/infarction, tendinopathy, atrophy, edema, deformity, neuropathic osteoarthopathy, callus, ulceration, and infection. The MR imaging appearance of these complications will be discussed. Recognition of these MR imaging patterns facilitates formulation of medical or surgical treatment plans.

Diabetic Foot↗
PubMed2001

MR imaging of inflammatory conditions of the ankle and foot.

Infection and noninfection inflammatory diseases commonly affect the foot and ankle; they have a significant impact on the cost of medical care and are a major source of referral for MR imaging evaluation. Recognition of the MR imaging appearance of the various manifestations of these disorders is important so that prompt and appropriate medical or surgical management can be instituted. This article emphasizes MR imaging of the most important diseases in this category, diabetic foot infection and the rheumatoid foot, but will also discuss manifestations in the foot and ankle of various other inflammatory diseases, such as gout and seronegative spondyloarthropathies.

Arthritis, Psoriatic↗