Elastography in the evaluation of liver allograft.

Elastography is an established technique in the evaluation of chronic liver diseases. While there is a large clinical experience and data available regarding the performance of elastography in native liver, elastography experience with liver grafts is limited and still growing. Both ultrasound-based elastography techniques and MR Elastography (MRE) are useful in the assessment of liver fibrosis in liver transplants. Technical modifications for performing elastography will be required for optimum evaluation of the graft. In general, caution needs to be exercised regarding the use of elastography immediately following transplantation as post-operative changes, perioperative conditions/complications, inflammation, and rejection can cause increased stiffness in the graft. In the follow-up, detection of increased stiffness with elastography is useful for predicting development of fibrosis in the graft. Adjunctive MRI or ultrasound with Doppler also provides comprehensive evaluation of anatomy, vascular anastomosis and patency, biliary tree, and stiffness for fibrosis. In this review, we provide a brief overview of elastography techniques available followed by the literature review of elastography in the evaluation of grafts and illustration with clinical examples.

Overview of the Mars Pathfinder mission and assessment of landing site predictions.

Chemical analyses returned by Mars Pathfinder indicate that some rocks may be high in silica, implying differentiated parent materials. Rounded pebbles and cobbles and a possible conglomerate suggest fluvial processes that imply liquid water in equilibrium with the atmosphere and thus a warmer and wetter past. The moment of inertia indicates a central metallic core of 1300 to 2000 kilometers in radius. Composite airborne dust particles appear magnetized by freeze-dried maghemite stain or cement that may have been leached from crustal materials by an active hydrologic cycle. Remote-sensing data at a scale of generally greater than approximately 1 kilometer and an Earth analog correctly predicted a rocky plain safe for landing and roving with a variety of rocks deposited by catastrophic floods that are relatively dust-free.

Magnetic properties experiments on the Mars Pathfinder lander: preliminary results.

Many of the particles currently suspended in the martian atmosphere are magnetic, with an average saturation magnetization of about 4 A. m2/kg (amperes times square meters per kilogram). The particles appear to consist of claylike aggregates stained or cemented with ferric oxide (Fe2O3); at least some of the stain and cement is probably maghemite (gamma-Fe2O3). The presence of the gamma phase would imply that Fe2+ ions leached from the bedrock, passing through a state as free Fe2+ ions dissolved in liquid water. These particles could be a freeze-dried precipitate from ground water poured out on the surface. An alternative is that the magnetic particles are titanomagnetite occurring in palagonite and inherited directly from a basaltic precursor.

Pheochromocytoma in an incidentally discovered asymptomatic cystic adrenal mass.

Cystic adrenal lesions can be either cortical or medullary, and distinguishing between these 2 types of lesions may be important in patient management. Pheochromocytomas, which are adrenal medullary neoplasms, typically manifest with hypertension, headaches, palpitations, tachycardia, sweating, and anxiety symptoms; however, 10% to 17% of patients with pheochromocytomas are asymptomatic. We describe a 67-year-old woman with lifelong headaches and recent persistent cough in whom a left cystic adrenal mass was incidentally discovered by computed tomography of the chest. A moderate increase in normetanephrine and total metanephrine values in two 24-hour urine samples suggested a pheochromocytoma. Computed tomography with use of contrast medium revealed ring enhancement of the cyst wall, a finding consistent with an adrenal medullary tumor. This report demonstrates the importance of repeated 24-hour urine samples to determine the metanephrine values together with contrast-enhanced computed tomography in a patient with nonspecific symptoms.

Arteriovenous fistula of the thyroid gland associated with spontaneous bleeding from a flow-induced aneurysm of the inferior thyroid artery.

A case of acute, spontaneous cervical hemorrhage caused by a ruptured aneurysm of the inferior thyroid artery is described. This lesion was accompanied by an arteriovenous fistula within the thyroid gland that caused a flow-induced aneurysm. Diagnosis and treatment were successfully performed by selective angiography with endovascular occlusion and embolization. Both diagnostic and therapeutic management are discussed, and the related literature is reviewed. To our knowledge, this is the first reported case of an aneurysm of a thyroid artery in conjunction with an intraparenchymatous arteriovenous fistula of the thyroid gland.

Clostridium difficile infection: risk factors, medical and surgical management.

BACKGROUND: Clostridium difficile has become recognized as a cause of nosocomial infection which may progress to a fulminant disease. METHODS: Literature review using electronic literature research back to 1966 utilizing Medline and Current Contents. All publications on antibiotic-associated diarrhea, antibiotic-associated colitis, and pseudomembranous colitis as well as C. difficile infection were included. We addressed established and potential risk factors for C. difficile disease such as an impaired immune system and cost benefits of different diagnostic tests. An algorithm is outlined for diagnosis and both medical and surgical management of mild, moderate and severe C. difficile disease. RESULTS: Diagnosis of C. difficile infection should be suspected in patients with diarrhea, who have received antibiotics within 2 months or whose symptoms started after hospitalization. A stool specimen should be tested for the presence of leukocytes and C. difficile toxins. If this is negative and symptoms persist, stool should be tested with 'rapid' enzyme immunoabsorbent and stool cytotoxin assays, which are the most cost-effective tests. Endoscopy and other imaging studies are reserved for severe and rapidly progressive courses. Oral metronidazole or vancomycin are the antibiotics of choice. Surgery is rarely required for selected patients refractory to medical treatment. The threshold for surgery in severe cases with risk factors including an impaired immune system should be low. CONCLUSION: C. difficile infection has been recognized with increased frequency as a nosocomial infection. Early diagnosis with immunoassays of the stool and prompt medical therapy have a high cure rate. Metronidazole has supplanted oral vancomycin as the drug of first choice for treating C. difficile infections.

Fracture interpretation using electronic presentation: a comparison.

The purposes of this study were to determine whether (1) fractures are interpreted differently after digitization and electronic presentation; (2) there are differences in accuracy between screen radiographs and electronic presentation; (3) differences in interpretation are a function of monitor resolution; and (4) differences in interpretation between radiographs and electronic images relate to radiological subspecialty. Forty cases with fractures of varying degrees of subtlety and 35 cases without fractures were interpreted. Radiographs were digitized with 2 different systems and displayed on 3 monitors of different spatial resolution. Four radiologists, with varying experience, were asked to decide whether fractures were present, absent, or they were uncertain. Accuracy of interpretation increased with improved electronic image presentation and monitor resolution. The sensitivity, specificity, and accuracy of fracture detection on System A were 63%, 98%, and 78%, respectively. The results were 72%, 98%, and 84% with System B. System C results were 81%, 97%, and 88% with Lumiscan 75, and 82%, 96%, and 88% with Lumiscan 150. Sensitivity, specificity, and accuracy results of the original radiograph interpretation were 89%, 95%, and 92%. Results were significantly different for System A. No significant differences were found for the other systems compared with film radiographs. System A did not have adequate monitors for interpretation of subtle fractures. Systems B and C were capable of displaying even subtle fractures. Our initial results indicate that interpretation with high-quality 1K x 1K monitors is substantially similar to radiograph interpretation.

Magnetic properties experiments on the Mars exploration Rover Spirit at Gusev Crater.

The magnetic properties experiments are designed to help identify the magnetic minerals in the dust and rocks on Mars-and to determine whether liquid water was involved in the formation and alteration of these magnetic minerals. Almost all of the dust particles suspended in the martian atmosphere must contain ferrimagnetic minerals (such as maghemite or magnetite) in an amount of approximately 2% by weight. The most magnetic fraction of the dust appears darker than the average dust. Magnetite was detected in the first two rocks ground by Spirit.