The prevalence of ICH in PRES was 19.4% in our series. Both SAH and IPH can occur in association with PRES, typically in a location approximating that of parenchymal edema.

We studied the membrane transporters that mediate intracellular pH (pH(i)) recovery from acidification in brainstem neurons from chemosensitive regions of neonatal rats. Individual neurons within brainstem slices from the retrotrapezoid nucleus (RTN), the nucleus tractus solitarii (NTS), and the locus coeruleus (LC) were studied using a pH-sensitive fluorescent dye and fluorescence imaging microscopy. The rate of pH(i) recovery from an NH(4)Cl-induced acidification was measured, and the effects of inhibitors of various pH-regulating transporters determined. Hypercapnia (15% CO(2)) resulted in a maintained acidification in neurons from all three regions. Recovery in RTN neurons was nearly entirely eliminated by amiloride, an inhibitor of Na(+)/H(+) exchange (NHE). Recovery in RTN neurons was blocked approximately 50% by inhibitors of isoform 1 of NHE (NHE-1) but very little by an inhibitor of NHE-3 or by DIDS (an inhibitor of HCO(3)-dependent transport). In NTS neurons, amiloride blocked over 80% of the recovery, which was also blocked approximately 65% by inhibitors of NHE-1 and 26% blocked by an inhibitor of NHE-3. Recovery in LC neurons, in contrast, was unaffected by amiloride or blockers of NHE isoforms but was dependent on Na(+) and increased by external HCO(3)(-). On the basis of these findings, pH(i) recovery from acidification appears to be largely mediated by NHE-1 in RTN neurons, by NHE-1 and NHE-3 in NTS neurons, and by a Na- and HCO(3)-dependent transporter in LC neurons. Thus, pH(i) recovery is mediated by different pH-regulating transporters in neurons from different chemosensitive regions, but recovery is suppressed by hypercapnia in all of the neurons.

A negative finding at facial physical examination reliably excluded fracture. Clinical variables positively associated with facial fracture included the following: GCS score of 8 or less, ISS of 16 or greater, alcohol intoxication according to BAC, intubation at presentation, loss of consciousness, and the presence of abnormal facial findings at physical examination.

Therapeutic/care management, level IV.

Intravascular thrombosis and thromboembolism are critical diagnoses which are frequently made on contrast-enhanced computed tomography (CECT) or Doppler ultrasound. For a variety of reasons, some patients with acute intravascular pathology are imaged using CT without intravenous contrast. In the acute setting, the increased Hounsfield unit (HU) density of the thrombus compared to the blood pool allows the diagnosis to be made, or at least suggested, on non-enhanced computed tomography (NECT). The increased density of the clot is commonly referred to as the "hyperdense vessel sign." This is a well-known finding in the setting of stroke, but hyperdense vessels can also signal arterial or venous thrombosis in the chest, abdomen, pelvis, and extremities. Once a hyperdense vessel sign is noted on NECT, further exploration with CECT, angiography, or ultrasound may then be performed. Here, we present a pictorial review of the appearance of acute intravascular thrombosis as seen on non-enhanced computed tomography.

This study aims to investigate the effect of iterative reconstruction (IR) on MDCT image quality and radiologists' ability to diagnose and grade blunt solid organ injuries. One hundred (100) patients without and 52 patients with solid organ injuries were scanned on a 64-slice MDCT scanner using reference 300 mAs, 120 kVp, and fixed 75 s delay. Raw data was reconstructed using filtered back projection (FBP) and three levels of iterative reconstruction (Philips iDose levels 2, 4, and 6). Four emergency radiologists, blinded to the reconstruction parameters and original interpretation, independently reviewed each case, assessed image quality, and assigned injury grades. Each reader was then asked to determine if they thought that IR was used and, if so, what level. There was no significant difference in diagnostic accuracy between FBP and the various IR levels or effect on the detection and grading of solid organ injuries (p > 0.8). Images reconstructed using iDose level 2 were judged to have the best overall image quality (p < 0.01). The radiologists had high sensitivity in detecting if IR was used (80 %, 95 % CI 76-84 %). IR performed comparably to FBP with no effect on radiologist ability to accurately detect and grade blunt solid organ injuries.

Expeditious imaging is critical in the initial evaluation of patients in the setting of blunt abdominal trauma. In particular, multidetector computed tomography (MDCT) plays a key role in the diagnosis of abdominal solid organ injuries and patient triage. Nonoperative management is the accepted management strategy for hemodynamically stable trauma patients with abdominal solid organ injuries. 1 In addition to identifying parenchymal injuries of abdominal solid organ injuries, MDCT also may detect traumatic vas cular injuries of abdominal solid organs that are predictors of nonoperative management failure. 1 The purpose of this review is to demonstrate the imaging features of abdominal solid organ injuries that are likely to alter management and thus represent injury features that the surgeon wants to know. Multidetector CT Protocols: Key to Accurate Diagnosis of Organ Injury DiagnosisPortal venous phase multidetector computed tomography (MDCT) imaging acquisition is highly sensitive, specifi c, and accurate in the identifi cation of parenchymal injuries and has been shown to have a high negative predictive value. 1 It has been demonstrated that the addition of arterial phase images enables the radiologist to better detect and characterize traumatic vascular injuries, which include bleeding and nonbleeding entities, compared with portal venous phase imaging alone. 2 In essence, the combination of arterial and portal venous phase MDCT imaging provides data that mimic the fi ndings of catheter angiography. Excretory phase (Ͼ5 minutes) imaging is helpful in determining the presence of a urinary leak. 3

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