Suk Joo Hong

Ultrasonographic measurements in cubital tunnel syndrome

The cubital tunnel is the most common site of ulnar nerve entrapment. Previous ultrasound studies have demonstrated enlargement of the ulnar nerve in cubital tunnel syndrome but did not report on the cubital tunnel itself. Twenty‐two individuals with cubital tunnel syndrome were evaluated with nerve conduction studies and ultrasound. The ultrasound measurement that most strongly correlated with conduction velocity was the ratio of ulnar nerve to cubital tunnel cross‐sectional area with the elbow flexed. Measurement of this ratio may improve the diagnostic accuracy of ultrasound in cubital tunnel syndrome, although further investigation is needed. Muscle Nerve, 2007

Ulnar nerve and cubital tunnel ultrasound in ulnar neuropathy at the elbow.

OBJECTIVE To determine the accuracy of the ultrasonographic measurement of ulnar nerve to cubital tunnel area for diagnosis of ulnar neuropathy at the elbow. DESIGN Patients with confirmed ulnar neuropathy at the elbow and normative, healthy volunteers were evaluated with high-resolution ultrasound. The cross-sectional areas (CSAs) of the ulnar nerve and cubital tunnel were measured with the elbow extended and flexed, and results from the 2 groups were compared. SETTING Electromyography laboratory and radiology department of a tertiary care center. PARTICIPANTS Twenty-seven patients with ulnar neuropathy at the elbow and 20 controls. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURE The ratio of ulnar nerve to cubital tunnel CSA with the elbow flexed. RESULTS The ulnar nerve, with the elbow flexed, was larger in those with ulnar neuropathy at the elbow, and this group also had larger cubital tunnels than did controls. In those with ulnar neuropathy at the elbow, the ratio of the ulnar nerve to cubital tunnel was .31, and in the controls it was .32, which was not significantly different (P=.89). CONCLUSIONS The ratio of ulnar nerve to cubital tunnel did not differentiate those with ulnar neuropathy at the elbow from controls.

MR differentiation of low-grade chondrosarcoma from enchondroma

PURPOSE To evaluate magnetic resonance (MR) imaging for the discrimination between low-grade chondrosarcoma and enchondroma. MATERIALS AND METHODS MR images of 34 patients who were confirmed with low-grade chondrosarcoma or enchondroma were retrospectively reviewed. After review of medical records, MR findings in 18 patients with low-grade chondrosarcoma and 16 patients with enchondroma were compared. MR images were retrospectively reviewed for the lesion location (central or eccentric; epiphysis, metaphysic, or diaphysis), margin, contour, mineralized matrix, endosteal scalloping, cortical expansion, cortical destruction, soft tissue mass formation, and periosteal reaction. Signal intensity, the patterns of contrast enhancement (unilocular or multilobular), soft tissue mass, and adjacent abnormal bone marrow and soft tissue signal were also reviewed. Statistical analysis was performed with chi-square test. RESULTS The patients with low-grade chondrosarcoma had a significantly higher incidence of MR findings (P<.05): predominantly intermediate signal on T1-weighted images [72% (13/18) in low-grade chondrosarcoma vs. 25% (4/16) in enchondroma], multilocular appearance on contrast-enhanced T1-weighted images [83% (15/18) vs. 44% (7/16)], cortical destruction [33% (6/18) vs. 0% (0/16)], a soft tissue mass [28% (5/18) vs. 0% (0/16)], adjacent bone marrow and soft tissue abnormal signal [22% (4/18) vs. 0% (0/16)], and an involvement of the epiphysis or flat bone [56% (10/18) vs. 19% (3/16)]. CONCLUSION MR imaging shows helpful features for differentiating low-grade chondrosarcoma from enchondroma.

Validation of a simple radiographic method to determine variations in pelvic and acetabular cup sagittal plane alignment after total hip arthroplasty

Background and purposeOrientation of acetabular component, influenced by pelvic tilt, body position, and individual variations affects the outcome following total hip arthroplasty (THA). Currently available methods of evaluation are either imprecise or require advanced image processing. We analyzed intersubject and intrasubject variability of pelvic tilt, measured by sagittal sacral tilt (ST) and its relationship with acetabular component tilt (AT) by using a simple method based on standard radiographs.Materials and methodsST was measured on lateral radiographs of pelvis including lumbosacral spine obtained in supine, sitting, standing, and lateral decubitus position for 40 asymptomatic THA patients and compared to computed tomography (CT) data obtained in supine position. AT was measured on lateral radiographs (measured acetabular tilt: MAT) in each position and compared to measurement of AT on CT and an indirectly calculated AT (CAT).ResultsMean ST changed from supine to sitting, standing, and lateral decubitus positions as follows: 26.5 ± 15.5° (range 4.6–73.4°), 8.4 ± 6.2° (range 0.6–24.5°), and 13.4 ± 8.4° (range 0.1–24.2°; p < 0.0001, p = 0.002, p = 0.006). The MAT on radiographs was not significantly different from the MAT measured on CT (p = 0.002) and the CAT (p = 0.06). There is a good correlation between change in ST and MAT in sagittal plane (r = 0.93).ConclusionMeasurement of ST on radiographs is a simple and reliable method to track changes in pelvic tilt in different body positions. There is significant intersubject and intrasubject variation of ST and MAT with postural changes and it may explain causes of impingement or instability following THA, which could not be previously explained.

Ultrasound Elastography of Lateral Epicondylosis: Clinical Feasibility of Quantitative Elastographic Measurements

OBJECTIVE The objective of our study was to investigate the clinical feasibility of ultrasound elastography for assessing patients with lateral epicondylosis and to establish an objective and quantitative method of elastographic measurement in the affected tendon. SUBJECTS AND METHODS A total of 97 symptomatic and 89 asymptomatic common extensor tendons from both elbows of 79 consecutive patients with lateral epicondylosis and 14 healthy participants were prospectively examined by gray-scale sonography, color Doppler sonography, and compression-based elastography. Real-time color-coded elastography was performed and quantified with two regions of interest: the adjacent subcutis (S1) for a reference area and the common extensor tendon (S2) for the target area. The mean strain ratio (S1/S2) was used for quantitative comparisons. The difference in the mean strain ratio between symptomatic and asymptomatic tendons was assessed with conditional regression analysis. RESULTS In symptomatic elbows, 87 of 97 tendons (89.7%) showed intratendinous hypoechogenicity, 86 of 97 (88.7%) showed swelling, and 70 of 97 tendons (72.2%) showed intratendinous hyperemia. Color-coded elastography revealed a soft area on 73 of 97 tendons (75.3%). The mean strain ratio was 1.45 (SD, 0.45) for symptomatic tendons and 2.07 (SD, 0.70) for asymptomatic tendons. The mean strain ratio of the symptomatic tendons was significantly lower than that of asymptomatic tendons (p < 0.001), indicating that the symptomatic tendons were softer. CONCLUSION Our results revealed that patients with lateral epicondylosis had significantly lower strain ratios in their common extensor tendon origins. Ultrasound elastography using quantitative strain ratio measurements could be a promising supplementary method to evaluate tendon abnormalities in lateral epicondylosis.

Pelvic osteolysis relationship to radiographs and polyethylene wear.

The relationship of radiographic pelvic osteolysis to computed tomographic (CT) volume and polyethylene wear remains controversial. We evaluated the sensitivity and specificity of radiographs in detecting osteolysis considering CT scan as the true value, in 118 hips with cementless cups. Correlation between osteolysis volume in CT, area of osteolysis in radiograph, and linear wear of polyethylene was assessed. The sensitivity and specificity of anteroposterior radiographs for detection of osteolysis was 57.6% and 92.9%, respectively. Addition of oblique radiographs increased the sensitivity to 64.4% without changing the specificity. The sensitivity increased to 92.8% for lesion more than 1000 mm(3). There was good correlation between 2-dimensional (2D) osteolytic area in radiograph and 3-dimensional (3D) volume (r = 0.74) in CT scan and linear wear of polyethylene showed good correlation with 3D CT volume (r = 0.62) and 2D area in radiograph (r = 0.60). Thus radiographs are useful to screen clinically significant osteolysis.

Analysis of adjacent fracture after percutaneous vertebroplasty: does intradiscal cement leakage really increase the risk of adjacent vertebral fracture?

ObjectiveThe purpose of this study was to evaluate the incidence and risk factors associated with adjacent vertebral fracture after percutaneous vertebroplasty (PVP) to treat osteoporotic vertebral compression fractures. We also investigated the effect of intradiscal cement leakage on adjacent vertebral fracture formation after PVP.Materials and methodsFrom January 2003 to March 2009, 188 patients (163 women, 25 men; mean age, 70.9 years; range, 42–92 years) who underwent 214 PVP sessions at 351 levels for osteoporotic vertebral compression fractures were retrospectively enrolled in this study. The effect of intradiscal cement leakage on new adjacent vertebral fracture formation after PVP was evaluated. Possible other risk factors were also analyzed using univariate and multivariate methods. The risk factors included age, gender, mean bone mineral density (BMD), the vertebral level treated, presence of an intravertebral cleft or cyst before treatment, kyphosis angle, wedge angle, and the injected cement volumes.ResultsDuring the follow-up periods, new adjacent vertebral fractures developed in 36 (10.3%) of 351 treated levels. For 91 (25.9%) levels, intradiscal cement leakage was detected on procedural fluoroscopic radiographs. There was no statistically significant association between intradiscal cement leakage and new adjacent vertebral compression fracture (p = 0.789). Among the other risk factors, only the vertebral levels treated, especially the thoracolumbar junction, showed a significant relationship to new adjacent vertebral fractures (univariate analysis, p = 0.037; multivariate analysis, p = 0.043).ConclusionsIntradiscal cement leakage does not seem to be related to subsequent adjacent vertebral compression fracture in patients who underwent PVP for treatment of an osteoporotic compression fracture. The thoracolumbar location of the initial compression fracture is the only factor correlated with an adjacent vertebral fracture after PVP.

Hepatocellular carcinoma in an ectopic liver: CT findings

Hepatocellular carcinoma (HCC) in an ectopic liver is very rare and its CT findings have never been reported. We present an ectopic HCC between the spleen and left diaphragm, mimicking a splenic neoplasm on the CT scan. A follow up CT at seven months postoperatively revealed multiple recurrent HCCs in the mother liver.

Magnetic resonance evaluation of fibrovascular ingrowth into porous polyethylene orbital implant.

We assessed the fibrovascular ingrowth into porous orbital implant with MRI. Twelve cases underwent T1WI, T2WI, Gd-enhanced T1WI, and Short Tau Inversion Recovery (STIR) images. Gd-enhanced T1WI showed homogeneous enhancement (n=4), peripheral and posterior part enhancement (n=7), and anterior part enhancement (n=1) of implants. High signal intensity portions on STIR images coincided with the enhancing portions on Gd-enhanced T1WI. Gd-enhanced T1WI is an excellent method for assessment of fibrovascular ingrowth into orbital implant and STIR images may be a comparable method to Gd-enhanced T1WI.

Imaging findings of femoroacetabular impingement syndrome: focusing on mixed-type impingement

The aim of our study was to analyze the imaging findings of femoroacetabular impingement (FAI). Eight consecutive patients [age range, 19-46 years (mean, 28.6 years); M/F ratio=7:1] who underwent operation for FAI were analyzed. We analyzed bump, acetabular retroversion and protrusion, and osteoarthritis in the radiographs. In MR arthrography, we analyzed alpha-angle, anterolateral labral tear, cartilage abnormality, herniation pit, paralabral cyst, subchondral cyst, and marrow edema. We correlated the imaging findings with operative findings. In the radiographs, all eight patients showed bump and osteoarthritis (Kellgren-Lawrence score II-IV), and five (62.5%) patients showed acetabular retroversion. In MR arthrography, anterolateral labral tear and mild cartilage abnormality (Outerbridge grade I and II) were seen in all eight patients; increased alpha-angle was seen in six cases (75%). Anterolateral labral tear, bump, and mild cartilage abnormality were seen in all eight patients during operation. According to the above findings, we divided the patients into three cam-type and five mixed-type FAI. In the five mixed-type FAI, both bump and acetabular retroversion were seen. The mixed-type FAI is the most prevalent type in our study. The main imaging findings of mixed-type FAI were acetabular retroversion, bump, and early osteoarthritis in radiographs, and anterolateral labral tear, cartilage abnormality, and increased alpha-angle in MR arthrography.