Can T2-weighted Dixon fat-only images replace T1-weighted images in degenerative disc disease with Modic changes on lumbar spine MRI?

OBJECTIVES: To evaluate the diagnostic performance and interobserver agreement of a magnetic resonance imaging (MRI) protocol that only includes sagittal T2-weighted Dixon fat and water images as an alternative to a standard protocol that includes both sagittal T1-weighted sequence and T2-weighted Dixon water images as reference standard in lumbar degenerative disc disease with Modic changes. METHODS: From February 2017 to March 2019, 114 patients who underwent lumbar spine MRI for low back pain were included in this retrospective study. All MRI showed Modic changes at least at one vertebral level. Two radiologists read the standard protocol and 1 month later the alternative protocol. All MRI were assessed for Modic changes (types, location, extension) as well as structural changes (endplate defects, facet arthropathy, spinal stenosis, foraminal stenosis, Schmorl nodes, spondylolisthesis, disc bulges, and degeneration). Interobserver agreement was assessed, as well as diagnostic performance using the standard protocol as reference standard. RESULTS: Interobserver agreement was moderate to excellent (kappa ranging from 0.51 to 0.92). Diagnostic performance of the alternative protocol was good for detection of any Modic change (sensitivity = 100.00% [95% CI, 99.03-100.00]; specificity = 98.89% [95% CI, 98.02-99.44]), as well as for detection of each Modic subtype and structural variables (sensitivity respectively 100% and ranging from 88.43 to 99.75% ; specificity ranging respectively from 97.62 to 100% and 99.58 to 99.91% ). CONCLUSIONS: Combined with T2-weighted Dixon water images, T2-weighted Dixon fat images provide good diagnostic performance compared to T1-weighted images in lumbar degenerative disc disease with Modic changes, and could therefore allow for a shortened protocol. KEY POINTS: • Combined with T2-weighted Dixon water images, T2-weighted Dixon fat images (in comparison to T1-weighted sequence) can provide good diagnostic performance in lumbar degenerative disc disease with Modic changes. • Interobserver agreement of the alternative protocol including sagittal T2-weighted Dixon fat and water images was substantial to excellent for every studied variable except for facet arthropathy. • A shortened MRI protocol including T2-weighted Dixon sequence without T1-weighted sequence could be proposed in this clinical setting.

Measurement of femoral head penetration in polyethylene using a 3-dimensional CT-scan technique.

BACKGROUND: Current techniques for measuring in vivo polyethylene wear suffer from a range of problems, resulting in an unacceptable lack of repeatability and/or insufficient accuracy when they are used to measure the low wear rates associated with new, highly crosslinked polyethylene. We describe an improved CT method for measurement of 3D femoral head penetration in PE acetabular cups that has sufficient accuracy and repeatability to allow assessment of the wear potential of modern implants. METHOD: The accuracy and repeatability of the CT-scan method was determined by blindly repeating measurements on a precisely calibrated 28-mm prosthetic head and by comparing them with direct metrological measurements on 10 acetabular specimens with in vitro wear from machining, and on 8 explanted acetabular specimens with in vivo wear. RESULTS: The intra- and interobserver errors in femoral head diameter were 0.036 mm (SD 0.044) and 0.050 mm (SD 0.022), respectively. CT estimated femoral head penetration in both all-poly and metal-backed acetabular components with accuracy ranging from 0.009 to 0.245 mm (mean 0.080; SD 0.067). INTERPRETATION: We found that the CT method is rapid, is accurate, and has repeatability and ease of availability. Using a slice thickness of 0.0625 mm, this method can detect wear­and also the threshold for the wear rate that causes osteolysis­much earlier than previous methods.

Long-term clinical and MRI results of open repair of the supraspinatus tendon.

UNLABELLED: Open repair of full-thickness tears of the rotator cuff generally improves function, although anatomic failures are not uncommon. We asked whether the presence or absence of an anatomic repair influenced outcomes. We retrospectively analyzed 47 patients (49 shoulders) treated by open proximalized reinsertion of the supraspinatus tendon for chronic retracted detachment. The mean age of the patients at the time of surgery was 59 years. At a minimum 60-month followup (mean, 87 months; range, 60-133 months), we observed an improvement in the age- and gender-adjusted Constant-Murley score from 67% preoperatively to 95% postoperatively and in the pain score. With the last followup MRI, the supraspinatus tendon had reruptured in five patients (12%); the presence of a rerupture did not negatively influence the functional result. Once healing of the repaired tendons was achieved, supraspinatus muscle atrophy never worsened. However, on MRI, fatty infiltration of the supraspinatus, infraspinatus, and subscapularis muscles increased postoperatively despite tendon healing. Radiographic centering of the humeral head was preserved and glenohumeral arthritis remained stable. Functional results were better when the standardized supraspinatus muscle area was greater than 0.5 at the final evaluation. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

High-resolution ultrasound in etiological evaluation of ulnar neuropathy at the elbow.

OBJECTIVE: Ulnar neuropathy at the elbow (UNE) involves mechanical compression and irritation of the ulnar nerve (UN) caused by environmental and dynamic abnormalities that can however also be found in asymptomatic patients. Using high-resolution ultrasound, we aimed to assess and compare the relevance of morphological and dynamic variants of the UN and its surrounding structures (UN abnormalities) in symptomatic and asymptomatic patients. METHOD: UN abnormalities in patients with UNE were assessed using high-resolution ultrasound and compared against unaffected arms (patients or healthy volunteers). RESULTS: We studied 234 arms of 117 individuals (89 with UNE and 145 control). Eighty-one percent of the arms with UNE compared to 40% of control (p=0.00001) showed UN abnormalities. While it was dislocated in 49% of arms with UNE compared to in 23% of control (p=0.004). CONCLUSION: The two-fold higher frequency of occurrence of UN abnormalities in arms with UNE indicates their causative or at least contributory role in such neuropathies. High-resolution ultrasound should be part of the initial evaluation of UNE in order to assess the etiology of the conflict.

[Bone mineral density after treatment for nasal polyposis]. / Traitement médical de la polypose naso-sinusienne. Effet sur la densité minérale osseuse.

PURPOSE: Medical treatment of nasal polyposis is based on corticotherapy, and the most frequent complication of long-term corticotherapy is corticosteroid-induced osteoporosis. OBJECTIVE: To assess bone mineral density after long-term, high-dose corticosteroid treatment for nasal polyposis. PATIENTS AND METHODS: Bone mineral density at the spine and hip was measured by absorptiometry in 32 patients who had received high doses of corticosteroids for nasal polyposis. None of them had a disease that interfered with bone mineral density RESULTS: Bone mineral density was measured in 32 patients (59% men) aged 49.7 +/- 3.7 years [range: 29 - 74] after corticosteroid therapy for a mean of 5.3 years [range: 2-22 years]. More than 70% of the patients had abnormal bone density (osteopenia or osteoporosis ) at the spine and 44% at the hip. Only eight (25%) patients had normal bone density at both the spine and hip. CONCLUSION: High doses of corticosteroids in the treatment of nasal polyposis affect bone mineral density. Assessment of the benefits and risks of endoscopic sinus surgery must take this iatrogenic risk into account.

The asymmetric profile of the acetabulum.

Despite the curvaceous profile of the acetabulum, orthopaedic surgeons have continued to implant hemispheric cups since the introduction of total hip arthroplasty. The geometric discrepancies between the natural acetabulum and implant can result in painful iliopsoas impingement attributable to prosthetic overlap at the anterior acetabular ridge over which the iliopsoas tendon extends to leave the pelvis. We expanded on previous in vitro observations of acetabular morphology using a large in vivo sample and quantified the dimensions of the psoas valley. We studied computed tomographic scans of 200 healthy hips from 50 men and 50 women. The acetabular ridges were digitized on three-dimensional bone reconstructions and their coordinates were manipulated in spreadsheets to deduce acetabular diameter, anteversion, and inclination and to plot the rim profile. Our results confirm the acetabular rim is an asymmetric succession of three peaks and three troughs. The psoas valley has the following shape distribution: 79% curved, 11% angular, 10% irregular, and 0% straight. The mean depth of the psoas valley is 5 mm and the latitude of its trough is on average 6 mm below the acetabular equator. The use of side-specific cups that replicate the curvaceous acetabular profile could prevent prosthetic overlap and reduce the incidence of iliopsoas impingement.

Acute torticollis in an adolescent: case report and MRI study.

STUDY DESIGN: A case report is presented. OBJECTIVES: To describe a typical case of acute adolescent torticollis in which a disc lesion was detected with magnetic resonance imaging. SUMMARY OF BACKGROUND DATA: Acute torticollis is attributed to atlantoaxial rotary fixation of unknown etiology. The current view is that the lesion is caused by synovial fold entrapment in the C1-C2 interspace. METHODS: In a 15-year-old male adolescent, magnetic resonance imaging was performed a few hours after the onset of torticollis, and 3 weeks after resolution of symptoms.RESULTS Increased signal intensity compatible with a fluid collection was seen in the right uncovertebral region at C2-C3. This lesion was probably linked to a sudden disruption of the disc collagen fibers, and had caused excessive lateral pressure, pushing C2 toward the left. Magnetic resonance imaging at 3 weeks was unremarkable. CONCLUSIONS: The authors think that the observed disruption was a sudden and abnormal instance of a normal and, usually, very slow process of cleft formation with extension into the fibrocartilaginous core in the uncovertebral region. It is felt that this lesion may be a frequent cause of torticollis in adolescents.

Massive tears of the rotator cuff treated with a deltoid flap.

We retrospectively reviewed the charts of 29 patients younger than 65 years at surgery treated with deltoid flap reconstruction for massive postero-superior rotator cuff tears. All tears involved supraspinatus and infraspinatus tendons and were associated with tendon stump retraction to the glenoid rim, a preservable long biceps tendon, and an intact subscapularis tendon. Mean follow-up was 10.5 years. Patient satisfaction rate was 89%. Mean global Constant score improved from 43 to 71.5 points, mean pain score from 6.3 to 13.2, mean anterior flexion from 100 to 157 degrees, and force in elevation from 2.3 to 3 kg. Two thirds of patients had no humeral head migration. Of the 18 patients whose flap was examined by magnetic resonance imaging, 15 had no tear and 12 had a flap signal of muscle intensity; mean flap thickness was 5 mm. Pre-operative factors associated with poorer outcomes were upwards humeral head migration with a subacromial space smaller than 6 mm, presence of glenohumeral osteoarthritis, and supraspinatus amyotrophy greater than 40%. Deltoid flap reconstruction is a valid option in this patient population.

Postoperative meniscus: assessment at dual-detector row spiral CT arthrography of the knee.

PURPOSE: To assess the effectiveness of dual-detector row spiral computed tomographic (CT) arthrography of the knee in the evaluation of the postoperative meniscus for recurrent or residual meniscal tear. MATERIALS AND METHODS: Spiral CT arthrography was performed in 20 patients who presented with pain after partial meniscectomy. Findings at the initial reading of the images and at two retrospective independent readings were compared with those at second-look arthroscopy performed in all patients. At initial interpretation, conventional criteria for meniscal tear were used, including partial- or full-thickness tear of any size and meniscal separation. At retrospective interpretation, criteria for meniscal tear included large partial- and full-thickness tear and meniscal separation but not small partial-thickness tear. Sensitivity and specificity for the detection of tear of the postoperative menisci were calculated for initial and retrospective readings. RESULTS: At initial interpretation, the sensitivity and specificity for the detection of tear of the postoperative menisci were 100% and 78%, respectively. At retrospective interpretation, the sensitivity and specificity for the detection of tear of the postoperative menisci were 79% and 89% at reading 1 and 93% and 89% at reading 2, respectively. CONCLUSION: Spiral CT arthrography is valuable for the assessment of postoperative menisci, but the application of conventional definitions of meniscal tear to arthrographic findings in postoperative menisci can lead to overestimation of the clinical importance of meniscal lesions.