Kathryn J. Stevens

Magnetic resonance imaging of articular cartilage of the knee: comparison between fat-suppressed three-dimensional SPGR imaging, fat-suppressed FSE imaging, and fat-suppressed three-dimensional DEFT imaging, and correlation with arthroscopy.

To compare signal‐to‐noise ratios (S/N) and contrast‐to‐noise ratios (C/N) in various MR sequences, including fat‐suppressed three‐dimensional spoiled gradient‐echo (SPGR) imaging, fat‐suppressed fast spin echo (FSE) imaging, and fat‐suppressed three‐dimensional driven equilibrium Fourier transform (DEFT) imaging, and to determine the diagnostic accuracy of these imaging sequences for detecting cartilage lesions in osteoarthritic knees, as compared with arthroscopy.

Comparison of minimally invasive and conventional open posterolateral lumbar fusion using magnetic resonance imaging and retraction pressure studies.

Objective To determine whether minimally invasive lumbar spinal fusion results in less paraspinal muscle damage than conventional open posterior fusion. Methods The maximum intramuscular pressure (IMP) generated by a minimally invasive and standard open retractor was compared in cadavers using an ultra-miniature pressure transducer. In a second clinical study, eight patients with either minimally invasive or open posterolateral lumbar spinal fusion underwent magnetic resonance imaging (MRI) scanning approximately 6 months post surgery. MRI was used to estimate edema and atrophy within multifidus, with T2 mapping and diffusion-weighted imaging allowing quantification of differences between the two surgical techniques. Results IMP measured with the minimally invasive retractor was 1.4 versus 4.7 kPa with the open retractor (P<0.001). The minimally invasive retractor produced a transient maximal IMP only on initial expansion. Maximum IMP was constant throughout open retractor deployment. Striking visual differences in muscle edema were seen between open and minimally invasive groups on MRI. The mean T2 relaxation time at the level of fusion was 47 milliseconds in the minimally invasive and 90 milliseconds in the open group (P=0.013). The mean apparent diffusion coefficient was 1357×10−6 mm2/s and 1626×10−6 mm2/s (P=0.0184), respectively. Conclusions The peak IMP generated by the minimally invasive retractor was significantly less than with the open retractor. Postoperatively, less muscle edema was demonstrated after the minimally invasive lumbar spinal fusion, with lower mean T2 and apparent diffusion coefficient measurements supporting the hypothesis that less damage occurs using a minimally invasive approach.

Ankle: Isotropic MR Imaging with 3D-FSE-Cube—Initial Experience in Healthy Volunteers

The purpose of this prospective study was to compare a new isotropic three-dimensional (3D) fast spin-echo (FSE) pulse sequence with parallel imaging and extended echo train acquisition (3D-FSE-Cube) with a conventional two-dimensional (2D) FSE sequence for magnetic resonance (MR) imaging of the ankle. After institutional review board approval and informed consent were obtained and in accordance with HIPAA privacy guidelines, MR imaging was performed in the ankles of 10 healthy volunteers (four men, six women; age range, 25-41 years). Imaging with the 3D-FSE-Cube sequence was performed at 3.0 T by using both one-dimensional- and 2D-accelerated autocalibrated parallel imaging to decrease imaging time. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) with 3D-FSE-Cube were compared with those of the standard 2D FSE sequence. Cartilage, muscle, and fluid SNRs were significantly higher with the 3D-FSE-Cube sequence (P < .01 for all). Fluid-cartilage CNR was similar for both techniques. The two sequences were also compared for overall image quality, blurring, and artifacts. No significant difference for overall image quality and artifacts was demonstrated between the 2D FSE and 3D-FSE-Cube sequences, although the section thickness in 3D-FSE-Cube imaging was much thinner (0.6 mm). However, blurring was significantly greater on the 3D-FSE-Cube images (P < .04). The 3D-FSE-Cube sequence with isotropic resolution is a promising new MR imaging sequence for viewing complex joint anatomy.

Driven equilibrium magnetic resonance imaging of articular cartilage: Initial clinical experience

To evaluate three‐dimensional driven equilibrium Fourier transform (3D‐DEFT) for image quality and detection of articular cartilage lesions in the knee.

High Hamstring Tendinopathy: MRI and Ultrasound Imaging and Therapeutic Efficacy of Percutaneous Corticosteroid Injection

OBJECTIVE The goals of this study were to review the MRI and sonographic findings in patients diagnosed clinically with high hamstring tendinopathy and to evaluate the efficacy of ultrasound-guided corticosteroid injections in providing symptomatic relief. CONCLUSION MRI is more sensitive than ultrasound in detecting peritendinous edema and tendinopathy at the proximal hamstring origin. Fifty percent of patients had symptomatic improvement lasting longer than 1 month after percutaneous corticosteroid injection, and 24% of patients had symptom relief for more than 6 months.

CT imaging and three-dimensional reconstructions of shoulders with anterior glenohumeral instability.

Glenohumeral instability is a common occurrence following anterior dislocation of the shoulder joint, particularly in young men. The bony abnormalities encountered in patients with glenohumeral instability can be difficult to detect with conventional radiography, even with special views. The aim of our study was to evaluate the bony abnormalities associated with glenohumeral instability using CT imaging with 3‐D reconstruction images. We scanned 11 patients with glenohumeral instability, one with bilateral symptoms; 10 were male, one female, and their ages ranged from 18–66 years. Contiguous 3 mm axial slices of the glenohumeral joint were taken at 2 mm intervals using a Siemens Somatom CT scanner. In the 12 shoulders imaged, we identified four main abnormalities. A humeral‐head defect or Hill‐Sachs deformity was seen in 83% cases, fractures of the anterior glenoid rim in 50%, periosteal new bone formation secondary to capsular stripping in 42%, and loose bone fragments in 25%. Manipulation of the 3‐D images enabled the abnormalities to be well seen in all cases, giving a graphic visualization of the joint, and only two 3‐D images were needed to demonstrate all the necessary information. We feel that CT is the imaging modality most likely to show all the bone abnormalities associated with glenohumeral instability. These bony changes may lead to the correct inference of soft tissue abnormalities making more invasive examinations such as arthrography unnecessary. Clin. Anat. 12:326–336, 1999.

Femoral nerve palsy : an unusual complication of anterior lumbar interbody fusion

Summary of Background Data Compression neuropathy of the femoral nerve has been reported as an uncommon complication of bleeding into the iliopsoas muscle. Objective The authors detected anatomic reasons of direct injury to the femoral nerve at the lower lumbar level. Methods Keeping the hip in extension during the course of carrying out anterior fusion on a previously failed posterior fusion was considered another causative factor of femoral nerve injury. Anatomical dissection confirmed the likelihood of this injury being produced in this situation. Results Femoral nerve traction and compression can occur after prolonged compression of the nerve within the psoas muscle stretched between an immobile lower lumbar spine and the lesser trochanter when the hip is kept in extension. In the patients described no other reasons for direct or indirect injury were identified. Conclusion Although uncommon, the complication should be kept in mind. It can be avoided by intraoperative hip flexion.

Imaging of the Wrist at 1.5 Tesla Using Isotropic Three-Dimensional Fast Spin Echo Cube

To compare three‐dimensional fast spin echo Cube (3D‐FSE‐Cube) with conventional 2D‐FSE in MR imaging of the wrist.

Imaging of the articular cartilage in osteoarthritis of the knee joint: 3D spatial-spectral spoiled gradient-echo vs. fat-suppressed 3D spoiled gradient–echo MR imaging

To compare three‐dimensional (3D) spatial‐spectral (SS) spoiled gradient‐recalled acquisition in the steady state (SPGR) imaging with fat‐suppressed 3D SPGR sequences in MR imaging of articular cartilage of the knee joint in patients with osteoarthritis.

Athletic Osteitis Pubis

Athletic osteitis pubis is a painful and chronic condition affecting the pubic symphysis and/or parasymphyseal bone that develops after athletic activity. Athletes with osteitis pubis commonly present with anterior and medial groin pain and, in some cases, may have pain centred directly over the pubic symphysis. Pain may also be felt in the adductor region, lower abdominal muscles, perineal region, inguinal region or scrotum. The pain is usually aggravated by running, cutting, hip adduction and flexion against resistance, and loading of the rectus abdominis. The pain can progress such that athletes are unable to sustain athletic activity at high levels. It is postulated that osteitis pubis is an overuse injury caused by biomechanical overloading of the pubic symphysis and adjacent parasymphyseal bone with subsequent bony stress reaction. The differential diagnosis for osteitis pubis is extensive and includes many other syndromes resulting in groin pain. Imaging, particularly in the form of MRI, may be helpful in making the diagnosis. Treatment is variable, but typically begins with conservative measures and may include injections and/or surgical procedures. Prolotherapy injections of dextrose, anti-inflammatory corticosteroids and a variety of surgical procedures have been reported in the literature with varying efficacies. Future studies of athletic osteitis pubis should attempt to define specific and reliable criteria to make the diagnosis of athletic osteitis pubis, empirically define standards of care and reduce the variability of proposed treatment regimens.