Ultrasound assessment of synovitis in total knee replacements: concordance with MR imaging and joint aspiration

OBJECTIVE

To determine if diagnostic ultrasound can reliably distinguish between synovial patterns of prosthetic joint infection and polymeric wear in total knee replacements.

METHODS AND METHODS

This retrospective study was approved by our hospital IRB. Using the radiology report database, MR examinations performed within a week of diagnostic ultrasound and/or ultrasound-guided aspiration were identified. This yielded (1) 24 cases with MR and ultrasound comparisons; (2) 44 cases with MR, ultrasound, and aspiration comparisons; and (3) 92 cases with ultrasound and aspiration comparisons. The MR studies were reviewed by a musculoskeletal radiologist. The ultrasound studies were each reviewed by 2 other musculoskeletal radiologists. Each study was graded for synovial pattern indicating infection, polymeric wear, or normal/nonspecific. Agreement between the MR grader and the ultrasound graders as well as ultrasound inter-rater agreement were assessed using k statistics. Sensitivity, specificity, positive predictive value, and negative predictive value of ultrasound were calculated.

RESULTS

Agreement between ultrasound and MR imaging was fair to moderate: k of 0.27 (95% CI: 0.04, 0.50) and 0.44 (95% CI: 0.23, 0.65) for ultrasound raters 1 and 2, respectively. Inter-rater agreement between ultrasound graders 1 and 2 was moderate, with k of 0.56 (95% CI: 0.42, 0.70). Ultrasound sensitivities for infection were 0.13 and 0.09, while specificities were 0.94 and 0.98. Ultrasound sensitivities for polymeric wear were 0.38 and 0.62 with specificities of 0.90 and 0.76.

CONCLUSION

Ultrasound does not perform well in distinguishing patterns of synovitis either compared to MRI or a reference standard of aspiration/clinical follow-up.

Diagnostic ultrasound of tendon injuries in the setting of distal radius fractures

OBJECTIVE

Describe tendon injuries and their structural causes seen on ultrasound in wrists with distal radius fractures and estimate the accuracy of ultrasound and its impact on clinical management.

MATERIALS AND METHODS

Ultrasounds of 226 wrists (221 patients) with distal radius fractures were retrospectively reviewed. Ultrasound findings of tendon injuries and their structural causes were correlated with surgery and clinical outcome. Accuracy and inter- and intra-observer reproducibilities were calculated.

RESULTS

Twenty-five wrists were treated non-operatively while 201 underwent surgery. Ultrasound demonstrated hardware contact with flexor pollicis longus (FPL) in 76 wrists, extensor pollicis longus (EPL) in 21, and other tendons in 94. Ultrasound identified tendon ruptures in 23 wrists (13 EPL/8 FPL/2 extensor indicis proprius (EIP)), most of which were surgically confirmed. Among 12 wrists with confirmed EPL ruptures, distal radius fracture had been treated with volar plating in 6 and non-operatively in 6, and ultrasound showed osseous irregularity at the rupture site in 8. All FPL ruptures occurred in wrists with volar plating. Ultrasound findings were concordant with subsequent clinical management in most. In 2, ultrasound findings led to the decision to remove hardware despite lack of symptoms. Ultrasound had sensitivity/specificity/accuracy of 88/99/98% for identifying a specific tendon as ruptured and 88/87/88% for tendon abnormalities in general. Inter- and intra-observer reproducibilities were excellent (kappa = 0.85 ~ 1.0).

CONCLUSION

Certain wrist tendons, particularly EPL and FPL, are vulnerable after distal radius fractures. Ultrasound is accurate and useful for detecting tendon injury and sources of tendon irritation and can guide clinical management.

Ferumoxytol-enhanced vascular suppression in magnetic resonance neurography

OBJECTIVE

To evaluate ferumoxytol-enhanced vascular suppression for visualizing branch nerves of the brachial plexus in magnetic resonance (MR) neurography.

MATERIALS AND METHODS

Signal simulations were performed to determine ferumoxytol's effect on nerve-, fat-, and blood-to-muscle contrast and to optimize pulse sequence parameters. Prospective, in vivo assessment included 10 subjects with chronic anemia who underwent a total of 19 (9 bilateral) pre- and post-infusion brachial plexus exams using three-dimensional (3D), T₂-weighted short-tau inversion recovery (T₂-STIR) sequences at 3.0 T. Two musculoskeletal radiologists qualitatively rated sequences for the degree of vascular suppression and brachial plexus branch nerve conspicuity. Nerve-to-muscle, -fat, and -vessel contrast ratios were measured.

RESULTS

Quantitative nerve/muscle and nerve/small vessel contrast ratios (CRs) increased with ferumoxytol (p < 0.05). Qualitative vascular suppression and suprascapular nerve visualization improved following ferumoxytol administration for both raters (p < .05). Pre- and post-ferumoxytol exams demonstrated moderate to near-perfect inter-rater agreement for nerve visualization and diagnostic confidence for the suprascapular and axillary nerves but poor to no agreement for the long thoracic nerve.

CONCLUSION

Ferumoxytol in T₂-weighted brachial plexus MR neurography provides robust vascular suppression and aids visualization of the suprascapular nerve in volunteers without neuropathy.

Ultrasound-guided aspiration of anterior cruciate ligament mucinous cysts in the posterior intercondylar notch: Technique and short-term outcomes

PURPOSE

To describe our technique of aspirating symptomatic anterior cruciate ligament (ACL) mucinous cysts in the posterior intercondylar notch with ultrasound guidance, and to detail short-term patient outcomes.

METHODS

We identified 13 patients from February 2008 to May 2020 who underwent ultrasound-guided aspiration of symptomatic ACL mucinous cysts in the posterior intercondylar notch. Post-procedural imaging was reviewed to evaluate the degree of cyst decompression. Needle size was noted. Post-procedural symptomatology was also assessed.

RESULTS

No or minimal fluid was initially aspirated in 11/13 (84.6%) patients. For the two patients in which the cysts were aspirated completely with initial needle placement, with no need for lavage, a 13-gauge trocar was utilized. Of the remaining cysts, 10/11 were aspirated with an 18-gauge needle and one with a 20-gauge needle. Subsequent lavage was performed in 10 of the remaining 11 patients. After lavage, in eight there was a reduction of at least 50% volume by retrospective image interpretation; of 25% to 50% volume in one patient and of less than 25% volume in one patient. Five of the 13 patients reported immediate post-procedural symptomatic relief. In the other patients, immediate efficacy or post-procedural symptomatology was not documented.

CONCLUSION

Aspiration of symptomatic ACL mucinous cysts is a safe procedure and can provide symptomatic relief that may be temporary, but useful clinically. We recommend needles larger than 18 gauge for the best chance of successful aspiration.

Etiology of Lumbosacral Radiculoplexopathy: Sacral Insufficiency Fracture on Magnetic Resonance Imaging

BACKGROUND

Sacral insufficiency fracture (SIF) can cause lumbosacral radiculoplexopathy (LSRP) and is probably under-recognized. Symptoms may include nonspecific lumbar spine or buttock pain that is exacerbated by physical activity and alleviated with rest. The frequency of LSRP secondary to SIF has not been reported.

QUESTIONS/PURPOSES

We aimed to determine the frequency of LSRP associated with SIF using magnetic resonance imaging (MRI) of the lumbar spine.

METHODS

We searched a radiology database at our institution using the keywords "sacral insufficiency fracture" and "lumbar spine MRI" for patient records from January 2014 through December 2017. We assessed for the presence of LSRP, reflected by elevated T2-weighted or short tau inversion recovery (STIR) signal intensity and enlargement of the nerve on noncontrast lumbar spine MRI. An incompletely healed vertically oriented SIF was confirmed if there was a persistent bone marrow edema pattern adjacent to the fracture site; we did not include purely transverse SIFs. The final cohort comprised 57 patients (48 female; age range, 14 to 89 years).

RESULTS

Abnormalities of the extraforaminal L5 nerve root or the combined L4 and L5 nerve roots (the lumbosacral trunk) were identified in 19 (33%) of 57 patients, with a total of 23 sites (bilateral involvement in four cases). Of the 23 abnormal nerves, 19 (82.6%) had corresponding, clinically documented radicular symptoms and 16 (69.6%) had no other explanation on MRI for their radicular symptoms other than SIF.

CONCLUSIONS

LSRP caused by SIF is an entity all radiologists should be cognizant of, especially in cases of otherwise unexplained radicular symptoms. The diagnosis of SIF can be helpful in cases involving concomitant multilevel lumbar spondylosis and neural foraminal stenosis.

Imaging evaluation of polyethylene liner dissociation in total hip arthroplasty

OBJECTIVE

To describe the imaging findings of polyethylene liner dissociation in total hip arthroplasty.

MATERIALS AND METHODS

Retrospective search of our institution's radiology database identified 12 patients with polyethylene liner dissociation of a total hip arthroplasty. Clinical and operative notes were reviewed. All radiological studies were reviewed independently by two radiologists.

RESULTS

Among 12 patients (seven females/five males; mean age: 67 years; median interval after surgery at diagnosis: 8.5 months) with polyethylene liner dissociation, 11 had radiographs, six had CT, seven had MRI, and two had arthrography. "Bubble sign" and "crescent sign" on radiography were insensitive, seen only in three patients, but all showed abrupt eccentric positioning of the femoral head. CT identified the dislocated liner in five of six patients but failed to identify one liner, which was partially associated with the acetabular cup. MRI identified the dislocated liner in all seven patients, with the MAVRIC (multiacquisition variable resonance image combination) sequences either increasing the diagnostic confidence relative to the routine pulse sequences or being the sole sequences in which the liner can be identified if the liner remained partially associated with the acetabular cup. Arthrography identified the dislocated liner in one of two patients.

CONCLUSIONS

Previously described radiographic signs of polyethylene liner dissociation are insensitive, but abrupt eccentric positioning of the femoral head in the correct clinical context is highly suggestive of the diagnosis. MRI and CT can accurately localize the displaced liner. MAVRIC is particularly helpful if the dislocated liner remains partially associated with the acetabular cup.

Ultrasound-Guided Biceps Tendon Sheath Injection: Spectrum of Preprocedure Appearances

OBJECTIVES

To determine the frequency of ultrasound (US) appearances of the extra-articular long head of the proximal biceps tendon in patients referred for US-guided biceps tendon sheath injections.

METHODS

We reviewed our US-guided biceps tendon sheath injections between January 2015 and December 2017, noting the appearance of the biceps tendon and sheath, as well as the needle size used, and what was injected. Clinical electronic medical records were also reviewed to determine safety and patients' responses.

RESULTS

A total of 300 US-guided biceps tendon sheath injections were performed for anterior shoulder pain. Preliminary US evaluations revealed that 129 of 300 (43%) patients had a normal US appearance of the biceps tendon; 110 (36.6%) had tendinosis; 13 (4.3%) had tenosynovitis; 31 (10.3%) had both tendinosis and tenosynovitis; 8 (2.7%) had a biceps tendon tear; and 9 (3%) had a history of a tenodesis. Of 81 patients who had pain relief after the injection, 41 had a normal tendon appearance on US, and 40 had an abnormal US appearance.

CONCLUSIONS

A large minority of patients with anterior shoulder pain clinically suspected to be due to the biceps tendon have a normal-appearing tendon and sheath. This should not dissuade the operator from performing the procedure.

Ultrasound Diagnosis of Osteophytic Impingement of the Popliteus Tendon After Total Knee Replacement

We report our experience with 6 patients who had total knee replacements with lateral-sided knee pain, referred for ultrasound (US) assessment and US-guided injection. All cases showed an osteophyte within the popliteus sulcus of the lateral femoral condyle impinging on the adjacent tendon. Five of 6 patients reported improvement of symptoms immediately after US-guided injection of an anesthetic and a steroid. Ultrasound has a unique role in the imaging of knee replacements because of its real-time capabilities and absence of artifacts at the popliteus tendon origin.

Sonographic evaluation of patellar clunk syndrome following total knee arthroplasty

Patellar clunk syndrome is a painful mechanical phenomenon that may develop following total knee arthroplasty. The diagnosis is usually made clinically, but cross-sectional imaging may be needed to confirm the clinical suspicion. Sonographic confirmation of patellar clunk syndrome can be obtained by directly visualizing the soft tissue proliferation deep to the distal quadriceps tendon and by dynamically demonstrating the clunking tissue during flexion and extension of the knee. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:105-107, 2017.

Screw placement accuracy for minimally invasive transforaminal lumbar interbody fusion surgery: a study on 3-d neuronavigation-guided surgery

Purpose The aim of this study was to assess the impact of 3-D navigation for pedicle screw placement accuracy in minimally invasive transverse lumbar interbody fusion (MIS-TLIF). Methods A retrospective review of 52 patients who had MIS-TLIF assisted with 3D navigation is presented. Clinical outcomes were assessed with the Oswestry Disability Index (ODI), Visual Analog Scales (VAS), and MacNab scores. Radiographic outcomes were assessed using X-rays and thin-slice computed tomography. Result The mean age was 56.5 years, and 172 screws were implanted with 16 pedicle breaches (91.0% accuracy rate). Radiographic fusion rate at a mean follow-up of 15.6 months was 87.23%. No revision surgeries were required. The mean improvement in the VAS back pain, VAS leg pain, and ODI at 11.3 months follow-up was 4.3, 4.5, and 26.8 points, respectively. At last follow-up the mean postoperative disc height gain was 4.92 mm and the mean postoperative disc angle gain was 2.79 degrees. At L5-S1 level, there was a significant correlation between a greater disc space height gain and a lower VAS leg score. Conclusion Our data support that application of 3-D navigation in MIS-TLIF is associated with a high level of accuracy in the pedicle screw placement.

The value of the internship for radiation oncology training: results of a survey of current and recent trainees

PURPOSE

Although a 12-month clinical internship is the traditional precursor to a radiation oncology residency, the continuance of this mandated training sequence has been questioned. This study was performed to evaluate the perceptions of current radiation oncology residents with respect to the value of their internship experience.

METHODS AND MATERIALS

A survey was sent to all US radiation oncology residents. Each was queried about whether they considered the internship to be a necessary prerequisite for a career as a radiation oncologist and as a physician. Preferences were listed on a Likert scale (1 = not at all necessary to 5 = absolutely necessary).

RESULTS

Seventy-one percent considered the internship year mostly (Likert Scale 4) or absolutely necessary (Likert Scale 5) for their development as a radiation oncologist, whereas 19.1% answered hardly or not at all (Likert Scale 2 and 1, respectively). With respect to their collective considerations about the impact of the internship year on their development as a physician, 89% had a positive response, 5.8% had a negative response, and 4.7% had no opinion. Although both deemed the preliminary year favorably, affirmative answers were more frequent among erstwhile internal medicine interns than former transitional program interns.

CONCLUSIONS

A majority of radiation oncology residents positively acknowledged their internship for their development as a specialist and an even greater majority valued it for their development as a physician. This affirmative opinion was registered more frequently by those completing an internal medicine internship compared with a transitional internship.