Optimizing contrast-enhanced abdominal CT in infants and children using bolus tracking

OBJECTIVE: Manual administration of IV contrast material results in unpredictable injection rates. Our purpose was to determine the effect of bolus tracking on overall abdominal helical CT scan quality, particularly on hepatic enhancement, in children with manually administered contrast media. MATERIALS AND METHODS: We compared 33 abdominal helical CT scans of 29 children in whom bolus tracking was used with 22 CT scans of a control group of 21 children in whom bolus tracking was not used. All contrast material was administered by manual injection. Qualitative assessment was made of organ and vessel enhancement and overall scan appearance. Quantitative assessment using region-of-interest cursors was performed at three anatomic levels, and the results for the two groups of children were compared. RESULTS: Qualitative comparison of enhancement parameters between the bolus tracking group (number given first) and the control group (number given second) yielded the following: splenic artifact in 9% versus 23% (p = .24); inferior vena cava flow artifact in 3% versus 27% (p = .01); scanning during the nephrographic phase in 89% versus 59% (p = .02); and good quality grade in 79% versus 64% (p = .23). Significantly greater hepatic enhancement (as measured in mean Hounsfield units) was achieved in the bolus tracking group than in the control group at the superior (48.5 versus 28.6; p < .001), middle (47.9 versus 32.3; p < .001), and inferior (48.2 versus 36.5; p = .01) levels. Hepatic enhancement increased significantly from the superior to the inferior level in the control group (p < .02), whereas enhancement was homogeneous in the bolus tracking group (p > .50). CONCLUSION: Bolus tracking provides improved contrast enhancement, including significantly greater hepatic enhancement, during abdominal helical CT in children in whom the rate of injection of contrast material is unpredictable.     

Nontumoral occipitotemporal epilepsy: localizing findings and surgical outcome

We describe a syndrome of medically intractable occipitotemporal epilepsy of nontumoral developmental origin and its treatment by surgery. From our epilepsy surgery database of 1988 to 1996, we selected all patients without neoplasm who had at least two characteristics localizing to the occipital lobe (clinical symptoms, interictal focus, ictal onset, or a lesion on magnetic resonance imaging scanning) and one to the temporal lobe (interictal spikes or seizure onset). We discuss seizure characteristics, electroencephalographic (EEG), magnetic resonance imaging, positron emission tomographic, and single-photon emission computed tomographic findings, pathological findings, surgical approach, outcome from resective surgery, and implications for pathophysiology. Sixty-nine percent of our 16 patients with occipitotemporal syndrome had neuronal migration disorder, suggesting a developmental etiology of this entity. Initial signs or symptoms suggested occipital lobe seizure onset in 13 of 16 patients. On scalp EEG, interictal spikes were localized to the temporal lobe in 9 and to the occipital lobe in 1; seizure onset was poorly localized. Intracranial EEG localized seizure onset to the area of temporo-occipital junction in 77% of patients. Positron emission tomography and single-photon emission computed tomography showed occipital and temporal or widespread deficits, and neuropsychological performance was diffusely abnormal. Surgical results were best with occipital and temporal resections, but sometimes satisfactory after occipital resection even with temporal (ipsilateral) EEG findings. Temporal resection with hippocampectomy uniformly failed to control seizures. An often refractory, probably developmental epileptic syndrome with regional occipitotemporal distribution can be diagnosed by a specific constellation of findings, which has implications for treatment and pathophysiology.     

Detection of Embolism with Doppler Ultrasound: A Review

Doppler detection of venous and arterial gas emboli has been recognized since 1968. The technology has been applied using 5-MHz ultrasound to study decompression sickness and monitor cardiopulmonary bypass and intracranial surgery. Since the advent of transcranial Doppler, which requires the use of lower ultrasonic carrier frequencies to penetrate the temporal bone, the detection of particulates moving in the bloodstream has been available. Using 2 MHz, microembolic signals have been detected in a variety of clinical situations, including cardiac conditions known to have high probabilities to produce embolic stroke. The basic features of a Doppler embolic signal have been clarified, and many investigators are applying the technology to determine the clinical significance of the detected emboli and their use in diagnosis and medical and surgical treatments. The basis for automatic sizing, counting, and characterizing the emboli is under development. The applications of Doppler detection of emboli will range from diagnosis and localization of embolic sources to improvement in surgical techniques and adjustments in medical treatments.     

Are you ready for a CLIA inspection?

Despite talk within the Clinton administration of watering down the Clinical Laboratory Improvement Amendments (CLIA) of 1988, currently CLIA is the law of the land. Federal officials say that physicians shouldn't expect any significant changes in the law until 1995 at the earliest. Already, surveyors have begun inspecting physician office laboratories across the country. This article, written by staff from ASIM's Medical Laboratory Evaluation (MLE) program, explains how to prepare your lab for inspection. The article originally appeared in "Focus On ... Physician Office Laboratories," a newsletter for MLE participants. More information on MLE is available by calling (202) 835-2746, ext. 274.     

The Role of Peritoneal Lavage in Severe Acute Pancreatitis

Encouraged by reports of the therapeutic efficacy of peritoneal lavage in small series of five or six patients with acute pancreatitis, we have evaluated this treatment in 24 patients with "severe" pancreatitis. One hundred and three patients with "severe" pancreatitis (28% mortality) were separated from 347 with "mild" pancreatitis (0.9% mortality) by previously described early objective signs. Early treatment (Day 0-7) of "severe" pancreatitis included peritoneal lavage through catheters placed nonoperatively in 18 (Group A) and by catheters placed at laparotomy in six (Group C). Early treatment of nonlavaged patients with "severe" pancreatitis was by standard nonoperative measures in 61 (Group B) and included early operation in 18 (Group D). Lavage was continued for 48-96 hours, usually using 36-48 L/24 hours of balanced isotonic dialysate fluid, and was uncomplicated. Lavage led to striking immediate clinical improvement and no lavaged patient (Groups A and C) died during the first 10 days of treatment of pancreatitis. By contrast, 45% of deaths in nonlavaged patients (Group B and D) occurred during this early period, usually from cardiovascular or respiratory failure. Although lavage reduced mortality in subgroups of patients, ultimate overall survival was no affected (Group A, 83%; B, 84%; C, 33%; D,33%). Late peripancreatic abscesses caused most deaths in lavaged patients. These data show that peritoneal complications of severe acute pancreatitis and dramatically reduces early mortality. Lavage does not prevent the late local sequelae of peripancreatic necrosis.