MR imaging mapping of skeletal muscle denervation in entrapment and compressive neuropathies.

The diagnoses of entrapment and compressive neuropathies have been based on the findings from clinical examinations and electrophysiologic tests, such as electromyography and nerve conduction studies. The use of magnetic resonance (MR) imaging for the diagnosis of entrapment or compressive neuropathies is increasing because MR imaging is particularly useful for discerning potential causes and for identifying associated muscle denervation. However, it is sometimes difficult to localize nerve entrapment or demonstrate nerve compression lesions with MR imaging. Nevertheless, even in these cases, MR imaging may show denervation-associated changes in specific muscles innervated by the affected nerves. The analysis of denervated muscle distributions by using MR imaging, with a knowledge of nerve innervation patterns, would be helpful for determining the nerves involved and the levels of nerve entrapment or compression. In this context, the mapping of skeletal muscle denervation with MR imaging has a supplementary or even a primary role in the diagnosis of entrapment and compressive neuropathies.

Skin and soft tissue infections: experience over a five-year period and clinical usefulness of ultrasonography-guided gun biopsy-based culture.

BACKGROUND: Skin and soft tissue infections (SSTIs) are common clinical diseases, but only a few reports of microbiological data on SSTIs in Korea have been published. In practice, specimens are rarely obtained from infected lesions unless there is visible pus or an abscess pocket. However, identification of the causative pathogen is important, because of emerging drug resistance and the increase in immunocompromised hosts. METHODS: The medical records of 760 adult cases of community-acquired SSTIs (CA-SSTIs) from September 2003 to August 2008 were reviewed retrospectively. We analyzed epidemio-clinical features and microbiological distributions of CA-SSTIs and evaluated the positive culture rate of several diagnostic methods, including swab, tissue biopsy, blind needle aspiration, ultrasonography (US)-guided needle aspiration, and US-guided gun biopsy. RESULTS: Most CA-SSTIs (76.1%) occurred in previously healthy persons without underlying diseases. Re-infections were identified in 76 (10%) patients and cirrhosis was an independent risk factor for re-infection (odds ratio 3.64, 95% confidence interval 1.36-9.76). The most commonly identified pathogen was methicillin-susceptible Staphylococcus aureus, and 3(rd)-generation cephalosporins were the most commonly used empirical antibiotics (47.9%). US-guided needle aspiration had a high positive culture rate of 73.9% and the positive culture rate of US-guided gun biopsy was 17.5%. CONCLUSIONS: Considering the microbiological distribution of CA-SSTIs in Korea, penicillinase-stable penicillin or a 1(st)-generation cephalosporin should be adequate for initial antibiotic treatment. US-guided needle aspiration was a good technique for the identification of causative pathogens, and additive productivity is expected with US-guided gun biopsy culture from lesions without fluid collection.

Fluoroscopically guided caudal epidural steroid injection for management of degenerative lumbar spinal stenosis: short-term and long-term results.

OBJECTIVE: To evaluate the short-term and long-term effects of fluoroscopically guided caudal epidural steroid injection (ESI) for the management of degenerative lumbar spinal stenosis (DLSS) and to analyze outcome predictors. MATERIALS AND METHODS: All patients who underwent caudal ESI in 2006 for DLSS were included in the study. Response was based on chart documentation (aggravated, no change, slightly improved, much improved, no pain). In June 2009 telephone interviews were conducted, using formatted questions including the North American Spine Society (NASS) patient satisfaction scale. For short-term and long-term effects, age difference was evaluated by the Mann-Whitney U test, and gender, duration of symptoms, level of DLSS, spondylolisthesis, and previous operations were evaluated by Fisher's exact test. RESULTS: Two hundred and sixteen patients (male:female = 75:141; mean age 69.2 years; range 48 approximately 91 years) were included in the study. Improvements (slightly improved, much improved, no pain) were seen in 185 patients (85.6%) after an initial caudal ESI and in 189 patients (87.5%) after a series of caudal ESIs. Half of the patients (89/179, 49.8%) replied positively to the NASS patient satisfaction scale (1 or 2). There were no significant outcome predictors for either the short-term or the long-term responses. CONCLUSION: Fluoroscopically guided caudal ESI was effective for the management of DLSS (especially central canal stenosis) with excellent short-term and good long-term results, without significant outcome predictors.

Spreading epidural hematoma and deep subcutaneous edema: indirect MRI signs of posterior ligamentous complex injury in thoracolumbar burst fractures.

OBJECTIVES: The purpose of this study was to evaluate the diagnostic value of a spreading epidural hematoma (SEH) and deep subcutaneous edema (DSE) as indirect signs of posterior ligamentous complex (PLC) injuries on MR imaging of thoracolumbar burst fractures. MATERIALS AND METHODS: We retrospectively reviewed spinal MR images of 43 patients with thoracolumbar burst fractures: 17 patients with PLC injuries (study group) and 26 without PLC injuries (control group). An SEH was defined as a hemorrhagic infiltration into the anterior or posterior epidural space that spread along more than three vertebrae including the level of the fracture. A DSE was regarded as a fluid-like signal lesion in the deep subcutaneous layer of the back, and its epicenter was at the burst fracture level. The frequency of the SEH/DSE in the two groups was analyzed. In addition, the association between each sign and the degree of vertebral collapse, the severity of central canal compromise, and surgical decisions were analyzed. RESULTS: Magnetic resonance images showed an SEH in 20 out of 43 patients (46%) and a DSE in 17 (40%). The SEH and DSE were more commonly seen in the study group with PLC injuries (SEH, 15 out of 17 patients, 80%; DSE, 16 out of 17 patients, 94%) than in the control group without PLC injuries (SEH, 5 out of 26, 19%; DSE, 1 out of 26, 4%) (P <0.0001). The SEH and DSE were significantly associated with surgical management decisions (17 out of 20 patients with SEH, 85%, vs 8 out of the 23 without SEH, 35%, P =0.002; 15 out of 17 with DSE, 88%, vs 10 out of 26 without DSE, 38%, P =0.002). The SEH and DSE did not correlate with the degree of vertebral collapse or the severity of central canal compromise. CONCLUSION: The SEH and DSE may be useful secondary MR signs of posterior ligamentous complex injury in thoracolumbar burst fractures.

Use of slide presentation software as a tool to measure hip arthroplasty wear.

The authors propose a manual measurement method for wear in total hip arthroplasty (PowerPoint method) based on the well-known Microsoft PowerPoint software (Microsoft Corporation, Redmond, Wash). In addition, the accuracy and reproducibility of the devised method were quantified and compared with two methods previously described by Livermore and Dorr, and accuracies were determined at different degrees of wear. The 57 hips recruited were allocated to: class 1 (retrieval series), class 2 (clinical series), and class 3 (a repeat film analysis series). The PowerPoint method was found to have good reproducibility and to better detect wear differences between classes. The devised method can be easily used for recording wear at follow-up visits and could be used as a supplementary method when computerized methods cannot be employed.

MR diskography and CT diskography with gadodiamide-iodinated contrast mixture for the diagnosis of foraminal impingement.

OBJECTIVE: This study was designed to investigate whether the use of MR diskography would result in improved reader confidence over the use of CT diskography alone for evaluating foraminal impingement causing lumbar radiculopathy. SUBJECTS AND METHODS: Sixteen disk levels in 14 consecutive patients with suspected foraminal impingement causing lumbar radiculopathy were prospectively included in the study. A mixture of diluted gadodiamide and iodinated contrast material was injected at each disk level. After diskography, a CT scan (CT diskography) and T1-weighted fat-suppressed MR image (MR diskography) were obtained. Two spine radiologists and an orthopedic spine surgeon independently scored CT diskography and MR diskography for foraminal evaluation on a 3-point scale: 1, low confidence; 2, moderate confidence; and 3, high confidence. Each reader also assessed whether MR diskography showed an additional benefit over CT diskography with regard to the depiction of foraminal abnormalities only. Another radiologist reviewed conventional MR images focused on disk height and morphology. RESULTS: The reviewers' confidence scores for MR diskography were superior to those for CT diskography (reader 1, p = 0.00008; reader 2, p = 0.0008; reader 3, p = 0.0015) (p < 0.05). MR diskography was considered beneficial in 13 of 16 disk levels (reader 1), 14 of 16 (reader 2), and 14 of 16 (reader 3). MR diskography increased the confidence scores for the detection of foraminal impingement, especially in cases of severe disk degeneration, but did not show additional benefits in cases of an extensive vacuum in the disk or large disk extrusion. CONCLUSION: Simultaneous MR diskography and CT diskography with a mixture of gadodiamide and iodinated contrast material may be beneficial for evaluating foraminal impingement causing lumbar radiculopathy.

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.

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

BACKGROUND AND PURPOSE: Orientation 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 METHODS: ST 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). RESULTS: Mean ST changed from supine to sitting, standing, and lateral decubitus positions as follows: 26.5 +/- 15.5 degrees (range 4.6-73.4 degrees ), 8.4 +/- 6.2 degrees (range 0.6-24.5 degrees ), and 13.4 +/- 8.4 degrees (range 0.1-24.2 degrees ; 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). CONCLUSION: Measurement 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.

Effectiveness of transforaminal epidural steroid injection by using a preganglionic approach: a prospective randomized controlled study.

PURPOSE: To prospectively evaluate the short- and midterm effectiveness of transforaminal epidural steroid injection (TFESI) for lumbosacral radiculopathy with respect to injection level. MATERIALS AND METHODS: Institutional review board approval and written informed consent were obtained. From March 2005 to February 2006, 239 consecutive patients (106 male, 133 female; mean age, 49.8 years; range, 13-82 years) who were scheduled to undergo lumbar TFESI were enrolled. The patients were randomly assigned to either the ganglionic (TFESI at the location of the exiting nerve root) or preganglionic group (TFESI at the supraadjacent intervertebral disk level). Follow-up was conducted within 1 month (short term) and more than 6 months (midterm) after injections. Short- and midterm outcomes were measured by using a visual analog scale and a four-grade scale. Univariate analysis (by using the Fisher exact and chi(2) tests) and multiple logistic regression analysis were performed to evaluate the relationship between possible outcome predictors (ganglionic or preganglionic injection levels, cause of radiculopathy, duration of symptoms, age group, and sex) and the therapeutic effect. RESULTS: Univariate analysis showed that the preganglionic group had a better treatment effect (99 of 112, 88.4%) than did the ganglionic group (90 of 127, 70.9%) at short-term follow-up (P = .001). Multiple logistic regression analysis showed that the only significant outcome predictor at short-term follow-up was injection level (odds ratio = 2.232, P = .037). No significant difference was identified regarding TFESI approach or cause of radiculopathy at midterm follow-up. CONCLUSION: TFESI for lumbosacral radiculopathy with a preganglionic approach is more effective than TFESI with a ganglionic approach at short-term follow-up.

US of ductal carcinoma in situ.

Little is known about the ultrasonographic (US) features of ductal carcinoma in situ (DCIS) of the breast because this entity usually manifests as pure mammographic calcifications and is rarely evaluated with US. US findings were recorded in 70 patients with DCIS and then analyzed and correlated with mammographic and histologic findings. A microlobulated mass with mild hypoechogenicity, ductal extension, and normal acoustic transmission was the most common US finding in DCIS. Spiculated margins, marked hypoechogenicity, a thick echogenic rim, and posterior acoustic shadowing at US often suggested the presence of invasion. US performed with a 10-13-MHz transducer and optimal technique can be used as a complement to mammography in detecting and evaluating DCIS of the breast, as it demonstrates breast lesions associated with malignant microcalcifications in most cases. The main benefit of identifying a US abnormality in women with mammographically detected DCIS is to allow the use of US to guide interventional procedures (eg, needle biopsy, needle localization). US may also be helpful in detecting DCIS without calcifications and in evaluating disease extent in women with dense breasts. Nevertheless, further research is needed to delineate the role of US in the evaluation of patients with DCIS.

Transcatheter arterial chemoembolization for hepatocellular carcinomas in patients with celiac axis occlusion.

PURPOSE: To verify the hypothesis that most instances of celiac axis occlusion in patients with hepatocellular carcinoma (HCC) are caused by diaphragmatic compression and, therefore, transcatheter arterial chemoembolization (TACE) can be performed through the compressed lumen of the celiac axis. MATERIALS AND METHODS: The authors attempted to perform TACE in 36 consecutive patients with HCC and celiac axis occlusion. Spiral computed tomographic (CT) images were available in 26 patients. Initially, catheterization of the hepatic arteries was attempted through the occluded celiac axis. If it failed, catheterization was performed through the pancreaticoduodenal arcades. The causes of celiac axis occlusion were evaluated based on spiral CT and angiographic findings, access routes, technical success rates, and related complications in superselective catheterization of hepatic arteries. RESULTS: Among the 26 patients who underwent spiral CT, diaphragmatic compression of the celiac axis was demonstrated in 23. Selective catheterization of hepatic arteries was possible through the occluded celiac axis in 23 patients (64%). In nine (25%) of the remaining 13 patients, TACE was performed through the dilated pancreaticoduodenal arcades from the superior mesenteric artery. As a procedure-related complication, celiac axis dissection occurred in one patient (3%). CONCLUSION: Most patients with celiac axis occlusion had arcuate ligament compression. In TACE, the celiac artery occlusion could be traversed directly and this should be the initial approach.