Fulminant clostridium difficile colitis: comparing computed tomography with histopathology: are they concordant?

A Total abdominal colectomy (TAC) is recommended for fulminant Clostridium difficile colitis (FCDC) because intraoperative assessment of diseased segments is inaccurate. To determine whether computerized tomography (CT) provides an accurate assessment of disease, we examined the concordance between CT and histopathologic colitis distribution in patients undergoing TAC for FCDC. The ileocolon was divided into seven distinct segments. Of 20 patients meeting criteria, the median interval between preoperative CT and TAC was 1.5 days (range, 0 to 23 days), and mortality was 65 per cent. The CT distribution of colitis was pancolitis in 12 patients and segmental in eight. Nine of the 12 patients with CT pancolitis had histologic pancolitis (75% concordance). Four of the eight patients with CT-diagnosed segmental disease had histologic segmental disease (50% concordance). For patients with FCDC, the distribution of colitis on CT agrees with the histopathologic extent of disease in the majority of patients. However, discordance between CT and histologic extent of disease was present in 25 to 50 per cent of patients. Therefore, the recommendation for TAC rather than segmental resection for FCDC remains justified.

Fulminant Clostridium difficile Colitis: Comparing Computed Tomography with Histopathology: Are They Concordant?

A Total abdominal colectomy (TAC) is recommended for fulminant Clostridium difficile colitis (FCDC) because intraoperative assessment of diseased segments is inaccurate. To determine whether computerized tomography (CT) provides an accurate assessment of disease, we examined the concordance between CT and histopathologic colitis distribution in patients undergoing TAC for FCDC. The ileocolon was divided into seven distinct segments. Of 20 patients meeting criteria, the median interval between preoperative CT and TAC was 1.5 days (range, 0 to 23 days), and mortality was 65 per cent. The CT distribution of colitis was pancolitis in 12 patients and segmental in eight. Nine of the 12 patients with CT pancolitis had histologic pancolitis (75% concordance). Four of the eight patients with CT-diagnosed segmental disease had histologic segmental disease (50% concordance). For patients with FCDC, the distribution of colitis on CT agrees with the histopathologic extent of disease in the majority of patients. However, discordance between CT and histologic extent of disease was present in 25 to 50 per cent of patients. Therefore, the recommendation for TAC rather than segmental resection for FCDC remains justified.

Vowel category dependence of the relationship between palate height, tongue height, and oral area

This article evaluates intertalker variance of oral area, logarithm of the oral area, tongue height, and formant frequencies as a function of vowel category. The data consist of coronal magnetic resonance imaging (MRI) sequences and acoustic recordings of 5 talkers, each producing 11 different vowels. Tongue height (left, right, and midsagittal), palate height, and oral area were measured in 3 coronal sections anterior to the oropharyngeal bend and were subjected to multivariate analysis of variance, variance ratio analysis, and regression analysis. The primary finding of this article is that oral area (between palate and tongue) showed less intertalker variance during production of vowels with an oral place of articulation (palatal and velar vowels) than during production of vowels with a uvular or pharyngeal place of articulation. Although oral area variance is place dependent, percentage variance (log area variance) is not place dependent. Midsagittal tongue height in the molar region was positively correlated with palate height during production of palatal vowels, but not during production of nonpalatal vowels. Taken together, these results suggest that small oral areas are characterized by relatively talker-independent vowel targets and that meeting these talker-independent targets is important enough that each talker adjusts his or her own tongue height to compensate for talker-dependent differences in constriction anatomy. Computer simulation results are presented to demonstrate that these results may be explained by an acoustic control strategy: When talkers with very different anatomical characteristics try to match talker-independent formant targets, the resulting area variances are minimized near the primary vocal tract constriction.

Toward articulatory-acoustic models for liquid approximants based on MRI and EPG data. Part I. The laterals

Magnetic resonance images of the vocal tract during the sustained phonation of /l/ (both dark and light allophones) by four native American English talkers are employed for measuring lengths, area functions, and cavity volumes and for the analysis of 3-D vocal tract and tongue shapes. Electropalatography contact profiles are used for studying inter- and intra-talker variabilities and as a source of converging evidence for the magnetic resonance imaging study. The general 3-D tongue body shapes for both allophones of /l/ are characterized by a linguo-alveolar contact together with inward lateral compression and convex cross sections of the posterior tongue body region. The lateral compression along the midsagittal plane enables the creation of flow channels along the sides of the tongue. The bilateral flow channels exhibit somewhat different areas, a characteristic which is talker-dependent. Dark /l/s show smaller pharyngeal areas than the light varieties due to tongue-root retraction and/or posterior tongue body raising. The acoustic implications of the observed geometries are discussed.

Toward articulatory-acoustic models for liquid approximants based on MRI and EPG data. Part II. The rhotics

Magnetic resonance images of the vocal tract during sustained production of [symbol: see text] by four native American English talkers are employed for measuring vocal-tract dimensions and for morphological analysis of the 3D vocal tract and tongue shapes. Electropalatography contact profiles are used for studying inter- and intra-talker variabilities. The vocal tract during the production of [symbol: see text] appears to be characterized by three cavities due to the presence of two supraglottal constrictions: the primary one in the oral cavity, and a secondary one in the pharyngeal cavity. All subjects show a large volume anterior to the oral constriction, which results from an inward-drawn tongue body, an anterior tongue body that is characterized by convex cross sections, and a concave posterior tongue body shape. Inter-subject variabilities are observed in the oral-constriction location and the way the constriction is formed. No systematic differences are found between the 3-D vocal tract and tongue shapes of word-initial and syllabic [symbol: see text]s. Tongue-shaping mechanisms for these sounds and their acoustic implications are discussed.

Comparison of hard- and soft-copy digital chest images with different matrix sizes for managing coronary care unit patients

OBJECTIVE

This study was to determine whether different digital display formats for portable chest radiographs of coronary care unit patients would provide comparable information for clinical care. In particular, we tried to ascertain whether 1024 x 1024 pixel (1K) images on a picture archiving and communication system (PACS) workstation would be comparable to 1760 x 2140 pixel (2K) images on workstations or to digital films. If comparability could be proved, we hypothesized that 1K workstations could considerably lower equipment and film costs and facilitate image transmission from point to point.

MATERIALS AND METHODS

Four chest radiologists read a panel of chest studies assembled from 98 coronary care unit patients, comparing 1K and 2K soft-copy images with digital hard copies. For all three image types for the 98 patients, the readers evaluated nine image parameters that the cardiologists deemed essential for clinical decision making. Two other chest radiologists reviewed each patient's three image types, historical chest images, current and prior radiologic reports, and medical record to determine the consensus, or "truth findings."

RESULTS

With one exception (small pleural effusions), the receiver operating characteristic analysis showed no significant differences in the clinical information derived from the three image types.

CONCLUSION

For clinical management in a coronary care unit, comparable information can be obtained from digital radiologic chest studies using a 1K x 1K soft-copy format, a 2K x 2K soft-copy format, or a hard copy (film). Substantial savings in cost and time are therefore possible by using soft-copy images and lower resolution (1K x 1K) workstations and, when necessary, by transmitting images on regular telephone lines.