Mr imaging of hepatic nodular regenerative hyperplasia

Nodular regenerative hyperplasia (NRH), a rare condition that is commonly associated with noncirrhotic portal hypertension, is not well described in the MR literature. Three patients at two institutions were identified who had both abdominal MR imaging and pathologic evidence of NRH. All examinations were performed at 1.5 T and included axial T1- and T2-weighted spin-echo (SE) images. The MR studies were reviewed by two radiologists in consensus. Two patients had multiple liver lesions that had high signal components on T1-weighted images and were predominantly isointense with liver on the T2-weighted images. One patient had no focal lesions identified. NRH, when visualized on MR images, appears as multifocal masses with shortened Tl and T2 similar to liver. NRH should be considered in the differential diagnosis of hepatocellular tumors, especially in patients with a predisposing condition.     

Alcohol and Platelet Function

Epidemiological studies have shown that moderate consumption of alcoholic beverages is inversely related to the incidence of the complications of coronary artery disease. The protective effect of ethanol may be partially attributable to an inhibitory effect of ethanol on platelets. This article summarizes the experimental observations that ethanol inhibits platelet responses to specific physiological agonists. In alcoholics, various platelet defects have been observed, but these may be influenced by metabolic factors rather than the presence of ethanol alone. The acute effects of ethanol on platelet functions both in vivo and ex vivo will be reviewed. Evidence will be presented demonstrating that ethanol added acutely in vitro inhibits phospholipase A₂ in stimulated platelets. The interaction of ethanol with other signal transduction pathways will also be discussed.     

Diagnosing intramuscular myxoma by fine-needle aspiration: A multidisciplinary approach

The gross and microscopic appearances of aspirates from ten intramuscular myxomas are reported. The specimens were obtained from seven women and three men, ages 43 to 75, who had tumors involving the muscles of the thigh (7), upper arm (2), and forearm (1). Magnetic resonance (MR) imaging performed in six of the ten cases revealed well-defined, sharply demarcated tumors exhibiting low signal intensity relative to muscle on the T1-weighted images. The tumors were hyperintense to muscle on T2-weighted images. All aspirated tissues were clear, tenacious, and viscous. Smears contained few spindled and histiocytoid cells in an abundant mucoid background. Spindle cells demonstrated long cytoplasmic processes that in areas intertwined to form fibrillar tangles. Nuclei were oval to spindled with fine chromatin and inconspicuous nucleoli. Capillaries were sparse with simple (nonplexiform) branching. The differential diagnosis of myxoid lesions of the extremities includes benign entities such as myxoid schwannoma and neurofibroma, mesenchymal repair, and ganglion cyst, as well as malignant neoplasms such as myxoid liposarcoma, fibrosarcoma, malignant fibrous histiocytoma, and extraskeletal chondrosarcoma. The findings of this study revealed that, although the cytologic features were suggestive of intramuscular myxoma, a definitive diagnosis was often difficult, owing to scant cellularity and lack of distinctive cytologic features. The MR imaging findings may be utilized as an adjunct to the cytologic features to more confidently suggest a diagnosis of intramuscular myxoma. Diagn Cytopathol 1994;11:255–261. © 1994 Wiley-Liss, Inc.     

Spirometric indices of early airflow obstruction.

Thirty cigarette smokers and 25 non-smoking controls, all men were evaluated by history, physical examination and simple spirometry. The history and physical examination were not of much use in predicting airflow obstruction. Forced mid-expiratory flow (FEF 25-75%) was abnormally low in 23 of the 30 subjects, while forced expiratory volume in 1 second (FEV1) and FEV1/FVC (forced vital capacity) were less sensitive. Thus simple spirometry is a useful screening tool to detect early airflow obstruction even when it is clinically undetectable.     

Three-dimensional reconstruction in routine computerized tomography of the skull and spine. Experience based on 161 cases.

Three-dimensional (3D) reconstruction in routine computerized tomography (CT) presupposes that the referring clinicians are motivated, software programs are of good quality, a second working console is available and manipulations are made by experienced persons. Maxillofacial surgery is the main, conventional indication, but the method is also used to plan the surgical treatment of craniofacial malformations and that of injuries and tumours. 3D reconstruction cannot replace a thorough analysis of the acquisition sections since its spatial definition is not as good as theirs. Without competing with pure research-work, a number of applications remain in the realm of speculative imaging, but it cannot be denied that 3D reconstruction has an interesting potential for teaching.     

Frontal Slab Composite Magnetic Resonance Neurography of the Brachial Plexus: Implications for Infraclavicular Block Approaches

Background: Magnetic resonance neurography (MRN) is an imaging method by which nerves can be selectively highlighted. Using commercial software, the authors explored a variety of approaches to develop a three-dimensional volume-rendered MRN image of the entire brachial plexus and used it to evaluate the accuracy of infraclavicular block approaches.

Methods: With institutional review board approval, MRN of the brachial plexus was performed in 10 volunteer subjects. MRN imaging was performed on a GE 1.5-tesla magnetic resonance scanner (General Electric Healthcare Technologies, Waukesha, WI) using a phased array torso coil. Coronal STIR and T1 oblique sagittal sequences of the brachial plexus were obtained. Multiple software programs were explored for enhanced display and manipulation of the composite magnetic resonance images. The authors developed a frontal slab composite approach that allows single-frame reconstruction of a three-dimensional volume-rendered image of the entire brachial plexus. Automatic segmentation was supplemented by manual segmentation in nearly all cases. For each of three infraclavicular approaches (posteriorly directed needle below midclavicle, infracoracoid, or caudomedial to coracoid), the targeting error was measured as the distance from the MRN plexus midpoint to the approach-targeted site.

Results: Composite frontal slabs (coronal views), which are single-frame three-dimensional volume renderings from image-enhanced two-dimensional frontal view projections of the underlying coronal slices, were created. The targeting errors (mean +/- SD) for the approaches-midclavicle, infracoracoid, caudomedial to coracoid-were 0.43 +/- 0.67, 0.99 +/- 1.22, and 0.65 +/- 1.14 cm, respectively.     

Infections à Campylobacter jejuni et à cytomégalovirus (CMV) associées au syndrome de Guillain-Barré (SGB)

Guillain-Barre syndrome (GBS) is a rare disease triggered by postinfectious mechanisms. The disease concerns all ages, and is widely distributed around the world. The principal risks are respiratory failure, especially during the initial phase of the disease, and persisting deficit at long term. Among the infectious known agents, Campylobacter jejuni and CMV represent more than 40% of GBS causes. The clinical presentation, and the long-term prognosis of GBS related to these two etiologies are different. The physiopathological mechanisms of the nervous attack are probably also different. There is no proof, at this time, that anti-infectious treatment can improve the prognosis. The treatment is based on the early use of immunomodulatory treatments like intravenous immunoglobulins or plasma exchanges.     

Halofuginone--an inhibitor of collagen type I synthesis--prevents postoperative formation of abdominal adhesions.

OBJECTIVE: To evaluate the effects of halofuginone, a specific inhibitor of collagen type I synthesis, on the postoperative formation of abdominal adhesions in rats. SUMMARY BACKGROUND DATA: Postoperative adhesions remain the leading cause of small bowel obstruction in the Western world. Surgical trauma causes the release of a serosanguineous exudate that forms a fibrinous bridge between two organs. This becomes ingrown with fibroblasts, and subsequent collagen deposition leads to the formation of a permanent adhesion. Most of the drugs used have been clinically ineffective, and none has been specific to a particular extracellular matrix molecule. Therefore, there are serious concerns about the toxic consequences of interfering with the biosynthesis of other collagens, other matrix proteins, or vital collagen-like molecules. METHODS: Adhesions were induced by scraping the cecum until capillary bleeding occurred. The adhesions were scored 21 days later. Halofuginone was either injected intraperitoneally (1 microg/25 g body weight) every day, starting on the day of operation, or added orally at concentrations of 5 or 10 mg/kg, starting 4 days before the operation. Collagen alpha1(I) gene expression was evaluated by in situ hybridization, total collagen was estimated by Sirius red staining, and collagen type III was detected by immunohistochemistry. RESULTS: The adhesions formed between the intestinal walls were composed of collagen and were populated with cells expressing the collagen alpha1(I) gene. Regardless of the administration procedure, halofuginone significantly reduced the number and severity of the adhesions. Halofuginone prevented the increase in collagen alpha1(I) gene expression observed in the operated rats, thus reducing collagen content to the control level. In fibroblasts derived from abdominal adhesions, halofuginone induced dose-dependent inhibition of collagen alpha1(I) gene expression and collagen synthesis. Collagen type III levels were not altered by adhesion induction or by halofuginone treatment. CONCLUSIONS: Upregulation of collagen synthesis appears to have a critical role in the pathophysiology of postoperative adhesions. Halofuginone, an inhibitor of collagen type I synthesis, could be used as an important tool in understanding the role of collagen in adhesion formation, and it may become a novel and promising antifibrotic agent for preventing postoperative adhesion formation.