Tripolar concentric EEG electrodes reduce noise.

OBJECTIVE: To assay EEG signal quality recorded with tripolar concentric ring electrodes (TCREs) compared to regular EEG electrodes. METHODS: EEG segments were recorded simultaneously by TCREs and regular electrodes, low-pass filtered at 35 Hz (REG35) and 70 Hz (REG70). Clips were rated blindly by nine electroencephalographers for presence or absence of key EEG features, relative to the "gold-standard" of the clinical report. RESULTS: TCRE showed less EMG artifact (F = 15.4, p < 0.0001). Overall quality rankings were not significantly different. Focal slowing was better detected by TCRE and spikes were better detected by regular electrodes. Seizures (n = 85) were detected by TCRE in 64 cases (75.3%), by REG70 in 75 (88.2%) and REG35 in 69 (81.2%) electrodes. TCRE detected 9 (10.6%) seizures not detected by one of the other 2 methods. In contrast, 14 seizures (16.5%) were not detected by TCRE, but were by REG35 electrodes. Each electrode detected interictal spikes when the other did not. CONCLUSIONS: TCRE produced similar overall quality and confidence ratings versus regular electrodes, but less muscle artifact. TCRE recordings detected seizures in 7% of instances where regular electrodes did not. SIGNIFICANCE: The combination of the two types increased detection of epileptiform events compared to either alone.

Methods for Measuring Seizure Frequency and Severity.

Counting seizures is not simple. Patients may not be aware of their seizures. Adherence to diary entry often is poor. Shake detectors pick up only seizures with rhythmic movements and suffer from false-positive results. Measurement of electrodermal response is a promising technology but sensitivity and specificity for partial seizures are uncertain. Video-electroencephalogram monitoring is accurate but of short duration and performed in an artificial and expensive environment. Invasive electroencephalogram electrodes can detect seizure-like patterns, sometimes of unknown clinical significance. Practical long-term electroencephalogram monitors are under development. Methods to rank seizure severity are subjective. New approaches and solutions are needed.

MDCT appearance of the appendix: how does the low-density barium sulfate oral contrast agent affect it?

We compared the effect of low-density barium sulfate neutral oral contrast agent on the diameter of normal appendix and its luminal content versus that of water on multidetector-row CT. CT scans of 24 patients who had been imaged on two separate occasions for the evaluation of pancreatic pathology, once with water and subsequently with low-density barium sulfate as the neutral oral contrast agent were evaluated (total of 48 scans). Studies were randomized and reviewed in consensus on a workstation in the stack mode by two radiologists blinded to the type of oral contrast. The appendix was measured at baseline and 10 days later to obtain an average diameter. Results of the water and low-density barium sulfate groups were compared using paired t test. Contents of the appendiceal lumen were also noted (gas, fluid, mixed, and collapsed appendix). The average diameter of the appendix for scans obtained with water and low-density barium sulfate was 4.09 ± 0.87 mm (median, 4.22 mm; range, 2.50-5.65 mm) and 4.13 ± 0.93 mm (median, 4 mm, range, 2.2-5.65 mm), respectively. This difference was not statistically significant (P = 0.69). There was no statistically significant difference in the appendiceal content when water or low-density barium sulfate were used as oral contrast (χ (2) = 4.25, P = 0.89). Low-density barium sulfate does not affect appendiceal content or diameter and, therefore, should not adversely affect evaluation of the appendix on multidetector row CT.

The use of the "puffed-cheek" computed tomography technique to confirm the diagnosis of pneumoparotitis.

Pneumoparotitis is a rare etiology of symptomatic parotid gland enlargement that is often misdiagnosed clinically. Pneumoparotitis results from air refluxing into the parotid ductal system via an incompetent Stensen duct orifice. We report a protracted case of pneumoparotitis evaluated with the "puffed-cheek" computed tomography technique to help confirm the diagnosis.

An unusual appearance of discitis due to gas-forming Escherichia coli with associated pneumocephalus.

STUDY DESIGN: Case report. OBJECTIVE: To report on an unusual case of isolated septic discitis, meningitis, pneumocephalus, and solid organ abscesses associated with urosepsis from gas-producing Escherichia coli. SUMMARY OF BACKGROUND DATA: Isolated septic discitis, or disc infection without involvement of adjacent vertebrae, following E. coli urosepsis is an unusual finding in the adult population and to our knowledge has not been reported previously. METHODS: The clinical manifestations and imaging findings of a patient with a history of back pain are described. The significance of the reported case is discussed. RESULTS: Laboratory finding and imaging studies revealed a Gram-negative sepsis associated with meningitis, discitis, pneumocephalus, and solid organ abscesses. Due to widespread involvement of multiple organs, the infection remained refractory to treatment, and the patient died. CONCLUSION: Our report adds to the literature by describing an unusual appearance of spine infection in an adult. Furthermore, it emphasizes the importance of a systematic approach to the diagnosis and treatment of low back pain.

Morphological analysis of pancreatic cystic masses.

RATIONALE AND OBJECTIVES: The aim of this study was to analyze the morphology of pancreatic cystic masses detected on multi-detector row computed tomography (MDCT) to determine whether single-dimension measurements of these masses are accurate reflections of their volumes. MATERIALS AND METHODS: Twenty-five pancreatic cystic masses detected on MDCT in 25 patients were evaluated. Pancreatic cysts were segmented on MDCT using commercially available software. All measurements were obtained twice by two independent investigators, and the means of values for segmented cyst volume (Vs) (milliliters), maximum transaxial diameter (millimeters), and elongation value (defined as 1 - [width/length], where 1 = ellipsoid and 0 = spherical) were reported for each cystic lesion. The volume of each cyst was also calculated (Vc) using the maximum transaxial diameter, with the hypothesis that the cyst was spherical. Student's t test was used to analyze the differences between values of Vs and Vc. Bland-Altman plots and Lin's concordance correlation were used to assess agreement between different measurement techniques. A P value < .05 denoted statistical significance. Interobserver variability was also determined using the Bland-Altman method. RESULTS: There was a significant difference between Vs and Vc (P < .0001). The elongation values ranged from 0.28 to 0.83 (mean, 0.57 +/- 0.12; median, 0.56). Mean interobserver variability was 1.7% (95% confidence interval, -4.89% to 8.30%). CONCLUSIONS: The results suggest that pancreatic cystic masses are not spherical. Therefore, a cyst's single largest transaxial dimension is not an accurate surrogate of its actual volume.