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Biomedical subjects

Stephen Ledbetter

Publications and source records attributed to Stephen Ledbetter.

8 recordsLinked to original sources
PubMed2005

Lowering the thyroid dose in screening examinations of the cervical spine.

The first objective of this study was to test the hypothesis that a lower-dose (14.1 mGy thyroid dose) protocol for helical computed tomography (CT) of the entire cervical spine demonstrates equivalent technical adequacy and diagnostic accuracy as the standard-dose protocol (26.0 mGy thyroid dose) used at our institution. The second objective was to estimate the excess thyroid cancer mortality for three cervical spine screening protocols. Eight patients underwent two helical CT acquisitions of the entire cervical spine (standard and lower dose); from these acquisitions, a database of 128 randomized images (64 standard dose and 64 lower dose) was constructed. Three radiologists evaluated each of the 128 images for technical adequacy and, if the image was technically adequate, diagnostic accuracy. Historical data of excess thyroid cancer mortality stratified by age and sex were used to estimate the impact of lowering the thyroid dose in cervical spine screening. Estimates used a linear extrapolation of mortality data. The lower-dose protocol for helical CT of the entire cervical spine demonstrates equivalent technical adequacy and diagnostic accuracy as the standard protocol. The excess thyroid cancer mortality is a function of patient age and sex; for 25-year-old men, the excess mortality per 100,000 patients is 96.7 (standard-dose CT), 52.4 (lower-dose CT), and 6.7 (radiographs alone, 1.8 mGy thyroid dose). The equivalent technical adequacy and diagnostic accuracy of a lower-dose protocol for helical CT of the entire cervical spine support its implementation in routine screening. The excess thyroid mortality emphasizes the need to maintain an open dialogue with our referring clinicians with respect to the mechanism of injury, clinical findings, and radiation risks.

Adolescent↗
PubMed2005

An ovary with a twist: a case of interesting sonographic findings of ovarian torsion.

An otherwise healthy young woman presented to the Emergency Department with abdominal pain. Multiple diagnoses were considered, as must be in cases of women with lower quadrant abdominal pain. Rapid identification of an abnormally enlarged ovary in close proximity to the opposite ovary on pelvic ultrasonography suggested the diagnosis of ovarian torsion. This was verified on laparoscopy. Of note is the fact that normal Doppler flow to both ovaries was demonstrated on pelvic ultrasound. We present this case, and its associated images, with the intent to highlight a readily identifiable sign of ovarian torsion for emergency physicians and to briefly review ovarian torsion's salient clinico-pathologic features.

Abdominal Pain↗
PubMed2004

Quantification of clinical consultations in academic emergency radiology.

RATIONALE AND OBJECTIVES: The purpose of this study is to quantify the impact of clinical consultation on the workload of an academic emergency radiology section. MATERIALS AND METHODS: Data from a 7-day audit (24 h/d) of the number and length of clinical consultations was expressed as the mean number of consultations per 24 hours and consultation minutes per 24 hours. Consultations performed on images acquired from outside institutions were noted. The attending radiologist consultation fraction was defined as the attending consultation minutes per 24 hours divided by the number of minutes of attending coverage per 24 hours. Using annualized work relative value units per full-time employee (wRVU/FTE) over the 7 days, the consultation value unit per full-time employee (CVU/FTE) was defined and calculated as the consultation fraction multiplied by the annual wRVU/FTE. RESULTS: For the attending radiologists, the consultation fraction was 0.13 and the CVU/FTE was 1216. Twenty-two percent of the total consultation minutes were spent on studies performed outside our institution. CONCLUSIONS: Clinical consultation represents a significant portion of the workload in academic emergency radiology. The consultation fraction describes the fraction of the radiologist's time spent in consultation, and the CVU/FTE expresses the workload of clinical consultations in terms of wRVU/FTE, the factor used most commonly to determine the academic radiologist's productivity and staffing.

Academic Medical Centers↗
PubMed2002

Bacterial aortitis resulting in rapid development of infective "mycotic" aneurysm.

Aortitis and aneurysms with an infective etiology, though uncommon, must be recognized at imaging so that early medical and surgical intervention can improve survival. We report a case in which serial CT scans illustrate the short-interval development of an infective "mycotic" aneurysm resulting from bacterial aortitis.

Journal Article↗
PubMed2002

Primary epiploic appendagitis.

The clinical presentation of primary epiploic appendagitis can mimic diverticulitis or appendicitis. Review of the pathologically confirmed cases in the English literature shows the majority of cases to arise from the sigmoid colon. Pathognomonic findings by computed tomography impact patient management, and it is thus important to recognize these in patients imaged in the emergency setting.

Journal Article↗
PubMed2002

Skin and thyroid dosimetry in cervical spine screening: two methods for evaluation and a comparison between a helical CT and radiographic trauma series.

OBJECTIVE: The first objective of this study was to test the hypothesis that estimates of radiation dose from an ionization chamber correspond to thermoluminescent dosimeter measurements in patients with suspected cervical spine injury. The second objective was to compare the radiation dose of a protocol using helical CT of the entire cervical spine with that of a protocol using radiography alone. SUBJECTS AND METHODS: Thermoluminescent dosimeter measurements of radiation dose to the skin over the thyroid were made in two patient groups: six patients evaluated with CT of the cervical spine and six patients evaluated with radiography. The skin dose for both groups was estimated with an ionization chamber, and the thermoluminescent dosimeter measurements and ionization chamber estimates of skin dose were compared for both groups. Using the ionization chamber, we estimated the radiation dose to the thyroid for all 12 patients. With these estimates, we computed the ratios of skin dose and thyroid dose (CT / radiography). RESULTS: Thermoluminescent dosimeter measurements correlated with ionization chamber estimates of skin dose in both patient groups. Using the ionization chamber estimates, we found that CT delivered 26.0 mGy to the thyroid. In the patients evaluated with radiography, the mean thyroid dose was 1.80 mGy (95% confidence interval, 1.05-2.55 mGy). Ionization chamber dose ratios (CT / radiography) for the skin and thyroid were 9.69 and 14.4 mGy, respectively. CONCLUSION: The correlation between the ionization chamber estimates and the thermoluminescent dosimeter measurements supports the use of ionization chamber estimates in future research. Although helical CT of the entire cervical spine is cost-effective in patients at high risk for fracture, the greater than 14-fold increase in the radiation dose to the thyroid emphasizes the importance of clinical stratification to identify patients at high risk for fracture and the judicious use of CT in patients with suspected cervical spine injury.

Adult↗