Patrick T. Liu

Chronic expanding hematoma of the thigh simulating neoplasm on gadolinium-enhanced MRI

Patients who present with slowly growing extremity masses are often imaged with MRI to be examined for possible tumors. In addition to cysts and neoplasms, chronic expanding hematomas should be considered in the differential diagnosis if the patient has a history of remote trauma. The presence or absence of internal contrast enhancement is often used to distinguish between hematomas and hemorrhagic neoplasms on MRI and CT. We present the unusual case of a patient who had a chronic expanding hematoma of the calf that demonstrated nodular internal enhancement on gadolinium-enhanced MRI, simulating a neoplasm.

Popliteal vascular entrapment syndrome caused by a rare anomalous slip of the lateral head of the gastrocnemius muscle

Popliteal vascular entrapment syndrome can result in calf claudication, aneurysm formation, distal arterial emboli, or popliteal vessel thrombosis. The most commonly reported causes of this syndrome have been anomalies of the medial head of the gastrocnemius muscle as it relates to the course of the popliteal artery. We report two cases of rare anomalous slips of the lateral head of the gastrocnemius muscle causing popliteal vascular entrapment syndrome.

The Vascular Groove Sign: A New CT Finding Associated With Osteoid Osteomas

OBJECTIVE We have observed that osteoid osteomas are frequently surrounded by thin curvilinear or serpiginous low-density grooves in the surrounding bone on CT examinations. We believe that these grooves represent prominent enlarged feeding arterioles, corresponding to recently published histologic findings. This study was performed to assess the sensitivity and specificity of this vascular groove sign for differentiating osteoid osteomas from other radiolucent bone lesions. MATERIALS AND METHODS The study group consisted of 42 patients with pathologically proven osteoid osteomas. The control group included 29 patients with radiolucent bone lesions other than osteoid osteomas. Two readers scored CT examinations of these lesions for the presence of the vascular groove sign, defined as one or more radiolucent linear or serpiginous grooves extending from the periosteal surface of bone down to the radiolucent tumor. Sensitivity and specificity values were calculated for each reader. Positive and negative predictive values, p values, and interobserver agreement values were calculated. RESULTS The sensitivity of the vascular groove sign for detection of osteoid osteoma was 73.8% for reader 1 and 76.2% for reader 2, specificity was 96.6% for reader 1 and 89.7% for reader 2, positive predictive value was 96.9% for reader 1 and 91.4% for reader 2, and negative predictive value was 71.8% for reader 1 and 72.2% for reader 2. The p value was less than 0.0001 for both readers. The interobserver agreement was very good, with a kappa value of 0.85. CONCLUSION The vascular groove sign is a moderately sensitive but highly specific sign for distinguishing osteoid osteomas from other radiolucent bone tumors on CT.

MR Cholangiopancreatography in the Detection of Symptomatic Ectopic Pancreatitis in the Small-Bowel Mesentery

WEB This is a Web exclusive article. ctopic or aberrant pancreas is a rare finding; the estimated incidence is 0.55–13.7% according to autopsy analyses [1]. Ectopic pancreas within the mesentery [2] and ectopic pancreatitis [3] have been recognized previously as separate findings but have not been documented concomitantly. Despite diagnostic advances, preoperative noninvasive evaluation is difficult, and patients have traditionally needed surgical excision for a definitive diagnosis. We present the case of a 57-yearold woman with mesenteric ectopic pancreatitis diagnosed using MR cholangiopancreatography (MRCP) who deferred surgery. To our knowledge, this is the first report in the English-language medical literature of an MRCP diagnosis of ectopic pancreatitis.

Informatics in Radiology: Efficiency Metrics for Imaging Device Productivity

Acute awareness of the costs associated with medical imaging equipment is an ever-present aspect of the current healthcare debate. However, the monitoring of productivity associated with expensive imaging devices is likely to be labor intensive, relies on summary statistics, and lacks accepted and standardized benchmarks of efficiency. In the context of the general Six Sigma DMAIC (design, measure, analyze, improve, and control) process, a World Wide Web-based productivity tool called the Imaging Exam Time Monitor was developed to accurately and remotely monitor imaging efficiency with use of Digital Imaging and Communications in Medicine (DICOM) combined with a picture archiving and communication system. Five device efficiency metrics-examination duration, table utilization, interpatient time, appointment interval time, and interseries time-were derived from DICOM values. These metrics allow the standardized measurement of productivity, to facilitate the comparative evaluation of imaging equipment use and ongoing efforts to improve efficiency. A relational database was constructed to store patient imaging data, along with device- and examination-related data. The database provides full access to ad hoc queries and can automatically generate detailed reports for administrative and business use, thereby allowing staff to monitor data for trends and to better identify possible changes that could lead to improved productivity and reduced costs in association with imaging services.

Correlation of Arthrodesis Stability with Degree of Joint Fusion on MDCT

OBJECTIVE The purpose of our study was to correlate clinically determined joint stability with the degree of bone fusion in the ankle or subtalar joint on MDCT examinations after arthrodesis. MATERIALS AND METHODS We performed a retrospective review of 42 consecutive MDCT examinations from 29 patients. All patients had previously undergone arthrodesis of their ankle or subtalar joints and had persistent or recurrent hindfoot or ankle pain. Two musculoskeletal radiologists examined in consensus sagittal 2-mm-thick reformatted slices, measuring on each image the length of the joint surface and the length of the fused portion of the joint space. The sum of the lengths of the fused segments on all slices was then divided by the sum of the lengths of the joint surfaces to calculate the fusion ratio. For the standard of reference, the medical records were reviewed and operative reports, diagnostic injections, and physical examinations were used to classify the joints as stable or unstable. RESULTS Twelve clinically unstable joints had fusion ratios of 0-32.8%, whereas 30 clinically stable joints had fusion ratios of 33.2-100%. Using receiver operating characteristic analysis, we selected the cutoff level that maximized Youdens index (the sum of sensitivity and specificity). Using a 33% fusion ratio as the lower limit cutoff for joint stability, the sensitivity was 100%; specificity, 100%; and accuracy, 100%. CONCLUSION After arthrodesis of the ankle or subtalar joint, MDCT scans can be used to determine whether that joint is likely to be stable if > 33% of the joint has visible bone fusion on sagittal MDCT images.

Portal hypertension due to a splenic arteriovenous fistula : A case report

We present an unusual case of portal hypertension due to splenic arteriovenous fistula. The patient was a multiparous woman who presented with portal hypertension manifested by variceal bleeding with no evidence of liver disease. Mesenteric angiography confirmed the presence of a 3.5-cm distal splenic artery aneurysm and a high-flow arteriovenous fistulous communication from the aneurysm into the splenic vein. Arteriovenous fistula should be suspected in a patient who presents with portal hypertension but without liver disease, especially in a multiparous woman who presents with variceal bleeding after a delivery. Surgical ligation of the fistula and angiographic embolization has been reported to be equally successful for this condition. Angiographic coil embolization, done in our patient, is a safe alternative to surgery for the treatment of splenic AVF in unstable patients.

Delayed ulnar neuropathy at the wrist following open carpal tunnel release.

Open carpal tunnel release is a common and successful treatment of median neuropathy at the wrist (carpal tunnel syndrome). We report a case of delayed ulnar neuropathy at the wrist with onset 2 months after open carpal tunnel release. Clinical findings, electrophysiological studies, magnetic resonance imaging, and surgical exploration demonstrated ulnar nerve compression at Guyons canal resulting from translocation of the carpal tunnel contents. To our knowledge, this is an unreported complication of open carpal tunnel release that merits wide appreciation. Muscle Nerve, 2005

A Reference Standard-Based Quality Assurance Program for Radiology

The authors have developed a comprehensive radiology quality assurance (QA) program that evaluates radiology interpretations and procedures by comparing them with reference standards. Performance metrics are calculated and then compared with benchmarks or goals on the basis of published multicenter data and meta-analyses. Additional workload for physicians is kept to a minimum by having trained allied health staff members perform the comparisons of radiology reports with the reference standards. The performance metrics tracked by the QA program include the accuracy of CT colonography for detecting polyps, the false-negative rate for mammographic detection of breast cancer, the accuracy of CT angiography detection of coronary artery stenosis, the accuracy of meniscal tear detection on MRI, the accuracy of carotid artery stenosis detection on MR angiography, the accuracy of parathyroid adenoma detection by parathyroid scintigraphy, the success rate for obtaining cortical tissue on ultrasound-guided core biopsies of pelvic renal transplants, and the technical success rate for peripheral arterial angioplasty procedures. In contrast with peer-review programs, this reference standard-based QA program minimizes the possibilities of reviewer bias and erroneous second reviewer interpretations. The more objective assessment of performance afforded by the QA program will provide data that can easily be used for education and management conferences, research projects, and multicenter evaluations. Additionally, such performance data could be used by radiology departments to demonstrate their value over nonradiology competitors to referring clinicians, hospitals, patients, and third-party payers.

Sclerotic bone metastases from sarcomatoid renal cell carcinoma

Abstract We present a case of sarcomatoid renal cell carcinoma with multiple sclerotic skeletal metastatic lesions. Renal cell carcinoma is frequently metastatic at presentation, with a high incidence of skeletal involvement, classically described as osteolytic. However, sclerotic or osteoblastic metastatic skeletal lesions from renal cell carcinoma are rare, with only two previous reports identified in the literature, neither of which involved the sarcomatoid variant of renal cell carcinoma. In our case the sclerotic metastases were characterized by bone scan, computed tomography (CT), magnetic resonance imaging (MRI), and histologic analysis.