Sonographic evaluation of common peroneal neuropathy in patients with foot drop.

The common peroneal nerve arises from the sciatic nerve and is subject to a variety of abnormalities. Although diagnosis is often is based on the clinical findings and electrodiagnostic tests, high-resolution sonography has an increasing role in determining the type and location of common peroneal nerve abnormalities and other peripheral nerve disorders. This article reviews the normal sonographic appearance of the common peroneal nerve and the findings in 21 patients with foot drop related to common peroneal neuropathy.

Cirrhotic right and left portal veins: how slow do they go? Identification of threshold velocities associated with subsequent development of hepatofugal flow.

OBJECTIVE: The purpose of this study was to identify threshold right and left portal vein sonographic velocities that are correlated with subsequent development of hepatofugal flow in the main portal vein (MPV), a marker of portal hypertension. METHODS: A database containing 6019 Doppler liver ultrasound reports from an academic hospital was parsed using a Visual Basic computer algorithm. Right and left portal vein velocities were identified from 65 patients who developed hepatofugal MPV flow. Patients with a liver transplant or transjugular intrahepatic portosystemic shunt were excluded. Similarly, right and left portal vein velocities were identified from 195 patients free of chronic hepatic disease. The right and left portal vein velocities of these 2 groups were analyzed using a receiver operating characteristic curve to identify threshold velocities with the optimal sensitivity and specificity for patients who will develop hepatofugal flow in the MPV. RESULTS: A threshold velocity of 11 cm/s in the right portal vein is associated with 81.8% sensitivity and 93.5% specificity in distinguishing patients who develop hepatofugal flow from otherwise healthy control subjects. Likewise, a threshold velocity of 8 cm/s in the left portal vein is associated with a 62.3% sensitivity and a 94.5% specificity. CONCLUSIONS: A threshold right portal vein velocity of 11 cm/s can be used with high sensitivity and specificity to identify patients who may develop hepatofugal flow in the MPV. A left portal vein velocity less than 8 cm/s is 94.5% specific for the development of hepatofugal flow.

ACR Appropriateness Criteria® right lower quadrant pain--suspected appendicitis.

The diagnostic imaging of patients presenting with right lower quadrant pain and suspected appendicitis may be organized according to age and gender and to the presence or absence of "classic" signs and symptoms of acute appendicitis. Among adult patients presenting with clinical signs of acute appendicitis, the sensitivity and specificity of CT are greater than those of ultrasound, with improved performance when CT is performed with intravenous contrast. The use of rectal contrast has been associated with decreased time in the emergency department. Computed tomography has also been shown to reduce cost and negative appendectomy rates. Both CT and ultrasound are also effective in the identification of causes of right lower quadrant pain unrelated to appendicitis. Among pediatric patients, the sensitivity and specificity of graded-compression ultrasound can approach those of CT, without the use of ionizing radiation. Performing MRI after inconclusive ultrasound in pregnant patients has been associated with sensitivity and specificity of 80% to 86% and 97% to 99%, respectively. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Prevalence of and factors associated with posterior tibial tendon pathology on sonographic assessment.

OBJECTIVE: To assess the frequency of and factors associated with supramalleolar posterior tibial tendon (PTT) pathology that often may be missed on sonography because of the limited field of view of ultrasound. DESIGN: Retrospective cross-sectional study. SETTING: Large academic center. PATIENTS: Patients with medial ankle pain and tenderness and with normal radiographs who presented for sonographic assessment (n = 217). METHODS: Two experienced musculoskeletal radiologists interpreted the studies by consensus. MAIN OUTCOME MEASUREMENT: PTT pathology. RESULTS: Of the 217 patients, 33.2% had grade 1 PTT pathology (n = 72), 14.3% had grade 2 pathology (n = 31), and 2.8% had grade 3 pathology (n = 6). When stratified by location, 29.0% of patients (n = 63) had inframalleolar abnormalities, 11.5% had retromalleolar pathology (n = 25), and 11 patients had supramalleolar pathology (5.1%). Four patients had PTT subluxation or dislocation. Age was significantly associated with PTT pathology (P = .02). A higher proportion of patients with supramalleolar (81.8%) and retromalleolar (72.0%) PTT pathology were women compared with patients who had inframalleolar (57.1%) PTT pathology. A higher proportion of patients with supramalleolar and retromalleolar PTT pathology had grade 2 tears compared with those with inframalleolar PTT pathology (36.4% for supramalleolar, 44.0% for retromalleolar, and 22.2% for inframalleolar pathology). CONCLUSIONS: We present one of the largest studies on PTT pathology. PTT pathology can occur in the supramalleolar area, a region that often is not assessed on imaging. Although data are unavailable with regard to whether the natural history of supramalleolar PTT is different from that of other regions, patients with supramalleolar PTT pathology had more severe grades of tear and increased prevalence of tenosynovitis and were more often women. It is essential to recognize supramalleolar PTT pathology so that consequences of nontreatment such as medial arch collapse can be prevented.

ACR Appropriateness Criteria on colorectal cancer screening.

Colorectal cancer remains one of the most common causes of cancer death in this country. This malignancy is ideally suited for screening because the detection and removal of the precursor adenomatous polyp can prevent most colorectal cancers from ever forming. The choice of a test for screening involves consideration of various individual parameters, including patient age and the presence of risk factors for the development of colorectal cancer. Computed tomographic colonography (CTC) has emerged as the leading imaging technique for colorectal cancer screening in average-risk individuals on the basis of the evidence presented in this paper. The double-contrast barium enema is an alternative imaging test that is appropriate particularly when CTC is not available. In 2008, the American Cancer Society guideline for colorectal cancer screening was revised jointly with the US Multi-Society Task Force on Colorectal Cancer and the ACR to include CTC every 5 years as an option for average-risk individuals. Computed tomographic colonography is also the preferred test for colon evaluation after an incomplete colonoscopy. Imaging tests including CTC and the double-contrast barium enema are usually not indicated for colorectal cancer screening in high-risk patients with polyposis syndromes or inflammatory bowel disease. This paper presents the new colorectal cancer imaging test ratings and is the result of evidence-based consensus by the ACR Appropriateness Criteria Expert Panel on Gastrointestinal Imaging.

ACR Appropriateness Criteria on Crohn's disease.

In the past decade, new therapeutic agents have been developed that permit gastroenterologists to treat virtually all forms of Crohn's disease. The success of these treatments depends on an accurate diagnosis of the nature and extent of disease. Fortunately, radiologists now possess a powerful arsenal of imaging techniques to guide the choice of therapy. This article discusses the usefulness of both traditional and newer imaging techniques in the management of Crohn's disease and its various clinical presentations.

Changes in passive mechanical properties of the gastrocnemius muscle at the muscle fascicle and joint levels in stroke survivors.

OBJECTIVES: To investigate the ankle joint-level and muscle fascicle-level changes and their correlations in stroke survivors with spasticity, contracture, and/or muscle weakness at the ankle. DESIGN: To investigate the fascicular changes of the medial gastrocnemius muscle using ultrasonography and the biomechanical changes at the ankle joint across 0 degrees, 30 degrees, 60 degrees, and 90 degrees knee flexion in a case-control manner. SETTING: Research laboratory in a rehabilitation hospital. PARTICIPANTS: Stroke survivors (n=10) with ankle spasticity/contracture and healthy control subjects (n=10). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASUREMENTS: At the muscle fascicle level, medial gastrocnemius muscle architecture including the fascicular length, pennation angle, and thickness were evaluated in vivo with the knee and ankle flexion changed systematically. At the joint level, the ankle range of motion (ROM) and stiffness were determined across the range of 0 degrees to 90 degrees knee flexion. RESULTS: At comparable joint positions, stroke survivors showed reduced muscle fascicle length, especially in ankle dorsiflexion (P< or =.048) and smaller pennation angle, especially for more extended knee positions (P< or =.049) than those of healthy control subjects. At comparable passive gastrocnemius force, stroke survivors showed higher fascicular stiffness (P< or =.044) and shorter fascicle length (P< or =.025) than controls. The fascicle-level changes of decreased muscle fascicle length and pennation angle and increased medial gastrocnemius fascicle stiffness in stroke were correlated with the joint level changes of increased joint stiffness and decreased ROM (P<.05). CONCLUSIONS: This study evaluated specific muscle fascicular changes as mechanisms underlying spasticity, contracture, and joint-level impairments, which may help improve stroke rehabilitation and outcome evaluation.

Invasive infections with community-associated methicillin-resistant Staphylococcus aureus after kidney transplantation.

We report two cases of invasive infections caused by Panton-Valentine leukocidin-positive, community-associated, methicillin-resistant Staphylococcus aureus (CA-MRSA) after kidney transplantation. This report emphasizes the clinical importance of considering CA-MRSA as a causative agent in the differential diagnosis of infections of the skin and soft tissues in organ transplant recipients.

Does ultrasound training boost Year 1 medical student competence and confidence when learning abdominal examination?

OBJECTIVES: Learning to perform physical examination of the abdomen is a challenge for medical students. Medical educators need to find engaging, effective tools to help students acquire competence and confidence in abdominal examination techniques. This study evaluates the added value of ultrasound training when Year 1 medical students learn abdominal examination. METHODS: The study used a randomised trial with a wait-list control condition. Year 1 medical students were randomised into 2 groups: those who were given immediate ultrasound training, and those for whom ultrasound training was delayed while they received standard instruction on abdominal examination. Standardised patients (SPs) used a clinical skills assessment (CSA) checklist to assess student abdominal examination competence on 2 occasions - CSA-1 and CSA-2 - separated by 8 weeks. Students also estimated SP liver size for comparison with gold-standard ultrasound measurements. Students completed skills confidence surveys. RESULTS: Proficiency in abdominal examination technique acquired from traditional instruction boosted with ultrasound training showed no advantage at CSA-1. However, at CSA-2 the delayed ultrasound training group showed significant improvement. Students uniformly underestimated SP liver sizes and the estimates were not affected by ultrasound training. Student confidence in both groups improved from baseline to CSA-1 and CSA-2. CONCLUSIONS: Ultrasound training as an adjunct to traditional means of teaching abdominal examination improves students' physical examination technique after students have acquired skills with basic examination manoeuvres.

Identification of adhesions on CT in small-bowel obstruction.

Identification of adhesions on computed tomography (CT) in cases of small-bowel obstruction (SBO) is currently a diagnosis of exclusion. The purpose of this study is to examine whether the presence of findings suggestive of an extraluminal band can be used as a CT sign for adhesive SBO. CT scans of 142 patients with surgically proven SBO performed within 72 h of exploratory surgery were reviewed. The studies were evaluated for the cause of SBO and the presence of extraluminal bands. An extraluminal band was considered present if there was a change in the conformation of the transition zone, suggesting extraluminal compression of the bowel by a linear obstructive band. The presence of extraluminal bands in the area of the transition zone had a high positive predictive value for adhesive SBO. Of the 73 cases in which bands were present, SBO was due to adhesions in 52 instances, with a corresponding positive predictive value of 71% (95% confidence interval 0.60-0.80) and a p value of 0.008. The extraluminal band was 61% sensitive and 63% specific for adhesive SBO. The presence of an extraluminal band on CT in the area of the transition zone in cases of SBO correlates well with a diagnosis of SBO secondary to adhesions. In the absence of a source of SBO, the presence of an extraluminal band can serve as a helpful diagnostic adjunct for adhesive SBO.

Ultrasound diagnosis of peroneal tendon tears. A surgical correlation.

BACKGROUND: Musculoskeletal ultrasound is an established diagnostic technique for the assessment of tendon injuries. The purpose of the present study was to determine whether ultrasound is effective for evaluating peroneal tendon injuries, with surgical findings used as the standard of reference. METHODS: Fifty-eight patients with a suspected peroneal tendon injury were prospectively evaluated with use of dynamic ultrasound. Twenty-five patients were found to have peroneal tendon tears and were managed operatively. Five patients with normal peroneal tendons on ultrasound examination also were managed operatively for other reasons and are included in the series as the peroneal tendons were inspected at the time of the procedure. Ultrasound and surgical criteria were used to grade the peroneal tendons on a scale from grade 0 (normal tendon) to grade III (tendon rupture). RESULTS: Of the sixty tendons that were evaluated operatively, twenty-five were found to be torn. The sensitivity, specificity, and accuracy of ultrasonography were 100%, 85%, and 90%, respectively. CONCLUSIONS: The use of dynamic ultrasound is effective for determining the presence or absence of a peroneal tendon tear and should be considered a first-line diagnostic tool.