Radiation exposure from head computed tomography scans in pediatric trauma

Background

We have previously reported that children receive significantly less radiation exposure after abdominal and/or pelvis computed tomography (CT) scanning for acute appendicitis when performed at our children's hospital (CH) rather than at outside hospitals (OH). In this study, we compare the amount of radiation children receive from head CTs for trauma done at OH versus those at our CH.

Methods

A retrospective chart review was performed on all children transferred to our hospital after receiving a head CT for trauma at an OH between July 2012 and December 2012. These children were then blindly case matched based on date, age, and gender to children at our CH.

Results

There were 50 children who underwent head CT scans for trauma at 28 OH. There were 21 females and 29 males in each group. Average age was 7.01 ± 0.5 y at the OH and 7.14 ± 6.07 at our CH (P = 0.92). Average weight was 30.81 ± 4.69 kg at the OH and 32.69 ± 27.21 kg at our CH (P = 0.81). Radiation measures included dose length product (671.21 ± 22.6 mGycm at OH versus 786.28 ± 246.3 mGycm at CH, P = 0.11) and CT dose index (53.4 ± 2.26 mGy at OH versus 49.2 ± 12.94 mGy at CH, P = 0.56).

Conclusions

There is no significant difference between radiation exposure secondary to head CTs for traumatic injuries performed at OH and those at a dedicated CH.     

Comparison of 10 different hemostatic dressings in an aortic injury

BACKGROUND: Uncontrolled hemorrhage is the leading preventable cause of death on the battlefield. Similarly, hemorrhage accounts for 80% of all deaths within the first 48 hours of injury in civilian trauma patients. New methods of hemostasis are required to reduce hemorrhagic mortality. The purpose of this study was to compare nine hemostatic dressings for their efficacy in controlling bleeding from an otherwise fatal aortic injury in a pig model. Each hemostatic dressing was compared with the current standard U.S. Army field gauze dressing for a 1-hour period. METHODS: Fifty-nine anesthetized pigs were instrumented with catheters and splenectomized. Nine test dressings (n = 5 per group) and two control groups (gauze, n = 9; suture, n = 5) were applied to a 4.4-mm aortotomy through the spraying jet of blood, and direct pressure was held for 4 minutes and then released. Survival, blood loss, and other variables were measured over a 1-hour period. RESULTS: All animals with fibrin dressing and those receiving suture repair (five of five in both groups) survived the 1-hour observation period with minimal bleeding in the postocclusion period (< 37 mL). Those in the other dressing groups exsanguinated within 10 minutes, except for two animals in the gauze group surviving 1 hour. CONCLUSION: With one 4-minute application, a single fibrin dressing stopped bleeding from an aortotomy, which was equivalent to sutured repair. No other test group exhibited any evidence of significant hemostatic efficacy.     

Cholelithiasis in infants, children, and adolescents

During the past two decades, cholelithiasis has been recognized in increasing numbers of pediatric patients. This diagnosis should be considered in the event of upper abdominal complaints, particularly when one or more risk factors are evident. The etiology may be unknown or may be related to risk factors, including hemolytic conditions. In recent years, it has become evident that approximately 80% of gallstones in children are not due to hemolytic disease and that the remaining 20% are related to recurring hemolysis. The diagnosis of gallstones is best confirmed with ultrasonography. Routine ultrasonographic evaluation should be performed at intervals for all children who received TPA for more than 4 weeks, particularly those who have had ileal resection or have had chronic enteritis (Crohn disease). Cholecystectomy is the procedure of choice for symptomatic children with cholelithiasis, regardless of age. Cholecystectomy is recommended for the asymptomatic child younger than 3 years of age when echogenic shadows have been present for at least 12 months following resumption of oral feedings or when the gallstones are radiopaque. Also, cholecystectomy is advised for asymptomatic children who are older than 3 years of age if ultrasonographic studies confirm that echogenic foci with shadowing are true stones and not echogenic sludge. Complications of common bile duct obstruction, pancreatitis, perforation with bile peritonitis, and life-threatening sepsis may thus be prevented. Morbidity and mortality following cholecystectomy are expected to be relatively low in the pediatric age group.     

An electrophysiological study of the effects of orthographic neighborhood size on printed word perception

In two experiments participants read words and pseudowords that belonged to either large or small lexical neighborhoods while event-related brain potentials (ERPs) were recorded from their scalps. In Experiment 1, participants made speeded lexical decisions to all items, while in Experiment 2 they engaged in a go/no-go semantic categorization task in which the critical items did not require an overt behavioral response. In both experiments, words and pseudowords produced a consistent pattern of ERP effects: items with many lexical neighbors (large neighborhoods) generated larger N400s than similar items with relatively fewer lexical neighbors (small neighborhoods). Reaction time (RT, Experiment 1), on the other hand, showed a different pattern consistent with previous behavioral studies. While words tended to produce a facilitation in RT for larger neighborhoods, pseudowords produced an inhibition effect. The findings are discussed in terms of recent theories of word recognition and the functional significance of the N400.     

Event-related potentials during discourse-level semantic integration of complex pictures

This study examined event-related potentials (ERPs) elicited in response to semantic processing of non-verbal stories. ERPs were recorded from 29 scalp electrodes on 16 participants while they viewed series of complex gray-scale pictures, each of which relayed a simple story. The final picture of each story was either congruous or incongruous with the preceding context. Participants made delayed meaningfulness judgments for each story. Averaged ERPs time-locked to the onset of the final picture were more negative for incongruous than congruous pictures. Two distinct components were sensitive to congruency. The first component peaked at approximately 325 ms (N300) and was distributed over central and frontal sites. The second component peaked at approximately 500 ms and also had a centro-frontal maximum but was more widespread than the earlier component (anterior N400). The distinct scalp topographies of these two negativities provide strong evidence that the N300 and N400 are separate and distinguishable components. Furthermore, the presence of the N300 in this exclusively pictorial task suggests that the N300 is specific to the semantic processing of non-verbal stimuli and is not due to linguistic mediation. This study also revealed that the N400 can be modulated by discourse-level coherence manipulations with pictures. Finally, the different patterns of ERP effects observed during the semantic processing of verbal and non-verbal information suggest that non-identical neuronal sources, and thus non-identical representational systems, are accessed by these different types of materials. These findings strongly support at least partial modularity of semantic representations and processing mechanisms in the human brain.     

Brain and ventricle instability during psychotic episodes of the schizophrenias

Recent reports from serial brain scans suggest that the rate of ventricular expansion and/or brain atrophy may be accelerated in at least some schizophrenics. The authors assessed the effect of state changes upon such findings.Within-subject 3D MRIs were assessed for ventricular and brain volumes during periods of [partial] remission and of exacerbation of psychosis. Additional scans at comparable within-subject SAPS were used to assess rates of change in volumes that were independent of SAPS changes.Correlations of changes of ventricle and brain volumes vs. change of SAPS cores between scans revealed that ventricle volumes decreased during a period of psychotic exacerbation and increased at a time of [partial] remission (r(p)=-0.666; P<0.0005); conversely, brain volumes increased during psychotic exacerbation and decreased at [partial] remission (r(p)=+0.448; P=0.032). Scans at comparable SAPS scores suggested that the majority of patients had rates of ventricular expansion comparable to controls (0.9+/-0.6 cc/year), though two patients appeared to have rates of ventricular increase of 4.5+/-2. 1 cc/year (Lilliefores P=0.036; K-means clustering F=17.75). Exacerbation of psychosis in schizophrenia is accompanied by evidence of brain swelling, especially of periventricular brain, with encroachment of brain substance upon ventricular volumes. Controlled for state changes, the majority of schizophrenics show rates of ventricular expansion or brain atrophy indistinguishable from controls.     

Fetal hepatic oxygen consumption under normal conditions in the fetal lamb

Previous measurements of fetal hepatic blood flow have relied on microsphere methodology. Estimates of fetal hepatic oxygen consumption (VO2), based on these measurements and the oxygen content difference across the fetal hepatic circulation, have been quite variable. To estimate hepatic VO2 in the fetal lamb by a different methodology, we applied the Fick principle using the steady-state uptake of indocyanine green (ICG) by the fetal liver to measure left hepatic blood flow in 10 pregnant ewes. Sampling catheters were inserted into the fetal external iliac artery, left hepatic vein, and umbilical vein. ICG was infused to steady state (for approximately 60 min) through a fetal brachial vein. Four sets of ICG concentration differences across the circulation of the left hepatic lobe were determined for each animal, and left hepatic lobe blood flow calculated. The oxygen concentration difference was measured simultaneously and VO2 of the left hepatic lobe calculated. In addition, we measured fetal VO2 and calculated the ratio of hepatic to fetal VO2. Left hepatic lobe blood flow was 382.30 ml/min/100 g tissue (COV = 0.32), a result statistically no different than in 4 animals with an independent measurement of hepatic blood flow using an ethanol equilibration method. Hepatic VO2 was 1.74 micromol/min/g tissue (COV = 0.13), and hepatic to fetal VO2 ratio was 18.23% (COV = 0.19). Our results indicate that normal fetal hepatic oxygen uptake per gram of tissue is less variable than previously suggested, and that ICG can be applied in the fetus for the purpose of hepatic blood flow measurement.     

Malignant transformation of an ovarian mature cystic teratoma presenting as a rectal mass

BACKGROUND: Squamous cell carcinoma arising from malignant degeneration of a mature cystic teratoma is rare with a reported incidence of approximately 1-3%. The most common presenting symptoms are lower abdominal pain and increasing abdominal girth of several months' duration. Approximately 50% of the patients present with FIGO stage I while 35-38% present with stage III diseases. CASE: The case described herein represents an unusual presentation and initial diagnostic dilemma of locally aggressive squamous cell carcinoma arising in an ovarian dermoid cyst, with invasion into the distal rectum and anal canal causing rectal bleeding similar to the presentation of anal squamous cell carcinoma. Despite aggressive surgical management with posterior exenteration and optimal tumor debulking followed by 5040-cGy pelvic radiation utilizing 25-MV photons, the patient developed pelvic recurrence at the vaginal cuff 6 weeks after completion of her adjuvant radiotherapy. She subsequently failed cis-platinum single-agent chemotherapy and died 9 months after her initial surgery and diagnosis. CONCLUSION: Squamous cell carcinoma in the anal canal, diagnosed by colonoscopy or proctoscopy, could be an unusual presentation of that arising from malignant degeneration of an ovarian dermoid cyst. This tumor may behave in a locally aggressive manner and be resistant to pelvic radiation or single-agent chemotherapy of cis-platinum. The current experience of adjuvant treatment after comprehensive staging and cytoreductive surgery reported in the world literature is limited, and the optimal management of the malignancy remains unclear.     

The effects of aging on the P3 component of the visual event-related potential

Visual stimuli were used to elicit ERPs in 108 normal subjects ranging in age from 8 to 90 years. Age-related differences were found for both P3 latency and amplitude. Children and elderly adults were found to have the latest P3s. The earliest P3s were found in subjects in their twenties. A curvilinear function best described the P3 latency/age relationship. Also, small but significant differences were observed between males and females in P3 latency. The relationship between P3 amplitude and age was strongly influenced by scalp location. P3 was largest at posterior electrode sites, but was not visible at frontal sites in young children. With increasing age P3 decreased in amplitude at the posterior sites and increased in amplitude at more frontal locations.