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D E Dupuy

Publications and source records attributed to D E Dupuy.

At least 19 recordsLinked to original sources
PubMed1998

Cartilage and subchondral bone thickness distribution with MR imaging.

RATIONALE AND OBJECTIVES: The authors mapped articular cartilage (AC) and subchondral bone (SB) thicknesses in human acetabula in vitro by using magnetic resonance (MR) imaging and validated AC measurements by using light microscopy. MATERIALS AND METHODS: Left and right acetabula from a deceased patient who had undergone left hemiarthroplasty were imaged with fat-suppressed spoiled gradient-recalled acquisition in the steady state (repetition time = 55 msec, echo time = 15 msec, flip angle = 50 degrees, matrix = 256 x 256, field of view = 8 cm). AC and SB thickness maps were generated from image data by using analytic geometry, which enabled correction for thickness overestimation due to oblique sectioning. Cartilage bone plugs were extracted from the acetabula, and light microscopy was used to validate the thickness measurements obtained with MR imaging. RESULTS: Standard errors between thickness measurements obtained with MR imaging and light microscopy were 0.37 and 0.33 mm for the left and right AC, respectively, which is consistent with the voxel resolution of the MR imaging sequence (0.31 x 0.31 x 0.8 mm). SB thickness of the cartilage plugs could not be reliably measured with light microscopy and, therefore, could not be validated. Contour maps showed that SB thickness gradients were rapid and focal compared with the rather smooth gradients in AC thickness; however, thicker AC was accompanied by thicker SB for left (r2 = .261, P = .0001) and right (r2 = .308, P = .0001) acetabula. Average thickness differences between left and right acetabular AC and SB were 0.13 mm (P = .015) and 0.11 mm (P = .026), respectively. Although it was the operated hip that had thicker articular tissues, the differences were within the pixel resolution (< 0.31 mm). CONCLUSION: AC and SB thickness distribution can be accurately determined by combining noninvasive MR imaging and analytic geometry, which may also provide a means for quantitative, longitudinal assessment of focal AC defects.

Acetabulum↗
PubMed1998

Computer-based speech recognition as a replacement for medical transcription.

OBJECTIVE: We have implemented computerized speech recognition in a high-volume clinical setting using a newly developed commercial software system. This paper compares the performance of the computerized system with conventional transcription during a trial week followed by 3 months of routine clinical use. CONCLUSION: The speech recognition system was used for 97% of the cases during the trial week and 87% of cases during the months of continuous use. For a similar mixture of cases, no change occurred in the length of reports after introduction of the computerized system. Speech recognition decreased the time until the report became available by 99% and resulted in a substantial savings in transcription costs. We conclude that speech recognition by computer is practical in a high-volume clinical implementation.

Cost-Benefit Analysis↗
PubMed1998

Accuracy of CT-guided needle biopsy of musculoskeletal neoplasms.

OBJECTIVE: The purpose of our study was to assess the accuracy of CT-guided biopsy of musculoskeletal neoplasms with respect to technique, anatomic site, and histology. MATERIALS AND METHODS: During a 3-year period (January 1992 to December 1994), 176 core needle biopsies and 45 fine-needle aspirations were performed under CT guidance on patients with musculoskeletal neoplasms. To assess the accuracy of these procedures, we compared the diagnosis at biopsy with the final diagnosis as determined at the time of definitive treatment of the lesion. All biopsy findings were categorized as a primary malignancy (excluding round cell lesions), round cell lesion, local recurrence, or metastatic carcinoma. In addition, each lesion was analyzed according to which biopsy technique was used, whether frozen tissue section or rapid cytologic evaluation was used, and at which anatomic site the mass was found. RESULTS: The accuracy for needle biopsy was 93% and that for fine-needle aspiration was 80%. The complication rate for both techniques was less than 1%. Accuracy rates for the four categories of primary malignancy, round cell lesion, local recurrence, and metastatic carcinoma were 87%, 75%, 94%, and 100%, respectively. The mismatch rates were similar in soft-tissue lesions (5/52) and bone lesions (16/169). Diminished accuracy was associated with round cell lesions (20%) and lesions located in the spine or the perivertebral region (20%). Nondiagnostic and insufficient specimens were found in 18 (8%) of the 221 patients. CONCLUSION. CT-guided biopsy of musculoskeletal malignancies is a safe and effective procedure if performed by a team of clinicians, pathologists, and radiologists who possess subspecialty expertise.

Biopsy, Needle↗
PubMed1997

Advances in imaging of the acute abdomen.

Over the last 10 years, the most significant advancement in imaging of the acute abdomen has been the development of helical CT imaging. Rapid breath-hold imaging and improved intravascular opacification have enabled radiologists to obtain volumetric data that can be viewed in smaller slice increments. Helical data can also be analyzed utilizing multiplanar and three-dimensional techniques. With its proven ability to diagnose a wide variety of conditions, CT remains the diagnostic modality of choice for imaging the surgical abdomen. There have been considerable improvements in image resolution in US with improvements in transducer technology. Ultrasonography often serves as the first study in evaluating the pediatric or female patient with right lower quadrant or pelvic pain. Computed tomography may be necessary if US is not diagnostic. Despite these technical advances, plain film radiography should be the first imaging study for suspected cases of bowel perforation or obstruction. Magnetic resonance imaging continues to evolve, with improvements in hardware and software design that allow for faster imaging, but current levels of availability in the acute setting preclude its wider use. Whereas further imaging is not necessary for patients presenting with classic signs and symptoms of various acute abdominal diseases, the atypical patient often requires careful diagnostic imaging. Close consultation between the radiologist and surgeon leads to studies appropriately tailored to meet the diagnostic challenge at hand.

Abdomen, Acute↗
PubMed1997

Knee and shoulder fractures: association of fracture detection and marrow edema on MR images with mechanism of injury.

PURPOSE: To assess the value of magnetic resonance (MR) imaging for enabling the classification of fracture mechanisms and to compare marrow edema caused by compressive forces with that caused by tensile forces. MATERIALS AND METHODS: In 62 knees or shoulders, 78 fractures were identified prospectively on MR images or plain radiographs; compressive or tensile forces were determined retrospectively to have caused impaction or distraction fractures, respectively. Edema was measured on T1-weighted images. Frequencies of fracture detection on MR images or plain radiographs were compared. RESULTS: Forty-nine (63%) and 29 (37%) fractures were attributed to compressive and tensile forces, respectively. Edema measured 31 mm +/- 10 in impaction fractures and 2.5 mm +/- 2.4 in distraction fractures (P < .001). MR images and plain radiographs of 63 fractures were compared. On MR images, distraction fractures, including four of seven Segond fractures, were missed more often than impaction fractures (P < .008). Fractures overlooked on MR images were associated with less edema (P < .003). CONCLUSION: On MR images, impaction fractures demonstrate prominent marrow edema, and distraction fractures demonstrate minimal edema. Impaction fractures are more often missed on plain radiographs, and distraction fractures are more often missed on MR images. Segond fractures should be suspected if MR images show lateral capsular ligamentous injury in the knee; in these cases, evaluation with plain radiography is warranted.

Adult↗
PubMed1997

Kinematic CT of the patellofemoral joint.

OBJECTIVE: The purpose of this study was to determine if kinematic CT can be applied to the patellofemoral joint using current slip-ring CT scanner design in patients with anterior knee pain and thus a suspected patellar tracking disorder. SUBJECTS AND METHODS: Twenty knees in 18 patients with anterior knee pain were evaluated with kinematic CT. A single 10-sec exposure of the patellofemoral joint was obtained during active flexion and extension. Static nonkinematic and loaded kinematic examinations were compared with unloaded kinematic studies in a subset of patients. The changes in lateral patellofemoral angle and lateral shift were measured. Video cine viewing of patellofemoral motion was used to subjectively grade image quality and patellofemoral abnormalities by consensus. RESULTS: Kinematic CT was successfully used in all 20 knees. In nine knees studied with static nonkinematic and unloaded kinematic images, the lateral patellofemoral angle improved an average of 4" on the kinematic images. In addition, lateral shift improved by an average of 3%, an improvement that was statistically significant (p = .01). In 10 knees studied with and without loading, the lateral patellofemoral angle decreased an average of 3% with loading. No significant change was seen in lateral shift. In all patients, cine viewing was thought to be more useful than single images. Cine viewing was of good or diagnostic quality in all 20 knees studied. Lateral patellar translation during extension was detected in eight of 20 kinematic studies. Lateral patellar tilting also was detected in eight of 20 kinematic studies. Narrowing of the articular space was detected in 12 of 20 knees. Six knees were determined to be normal. CONCLUSION: Kinematic CT with slip-ring technology is a new technique that can be easily performed on the patellofemoral joint. This technique shows promise as a tool for determining the cause of anterior knee pain.

Adolescent↗
PubMed1996

Quantification of articular cartilage in the knee with three-dimensional MR imaging.

RATIONALE AND OBJECTIVES: To determine the volume of articular cartilage in cadavers, patients, and healthy volunteers by using a volumetric, fat-suppressed spoiled gradient-recalled signal acquisition in the steady state (SPGR) magnetic resonance (MR) sequence. METHODS: Sagittal MR images were obtained with a fat-suppressed SPGR sequence (repetition time, 52 msec; echo time, 10 msec; 60 degrees flip angle; 3.0-3.5-mm partitions, 256 x 192 matrix, two signals acquired). The cartilaginous surfaces of the tibia, femur, and patella were planimetrically defined with a three-dimensional workstation. A three-dimensional model volume was created by threshold segmenting the cartilage from the adjacent tissues. The volume as calculated by using MR imaging was compared with the actual volume of the cartilage specimens. RESULTS: Observed measurements correlated with actual weight and volume displacement measurements with an accuracy of 82%-99% and linear correlation coefficients of 0.99 (P = 2.5e-15) and 0.99 (P = 4.4e-15). Precision of segmentation in healthy volunteers yielded a coefficient of variation of 0.4% for interobserver variability and 0.3% for intraobserver variability. CONCLUSION: This pilot study suggests that accurate volumetric calculations of knee articular cartilage are possible with currently available MR imaging pulse sequences and a commercially available work station.

Adult↗
PubMed1996

Articular muscle of the knee: a muscle seldom recognized on MR imaging.

OBJECTIVE: We studied the MR imaging characteristics of the articular muscle of the knee, an important but seldom recognized structure of the distal thigh and knee. SUBJECTS AND METHODS: We used a 1.5-T system to prospectively evaluate the articular muscle of the knee in five healthy volunteers (10 knees); then we retrospectively studied the knee examinations of 24 patients (30 knees). One reader made duplicate readings to prospectively assess the sagittal proton density-weighted and axial T1-weighted images of the healthy volunteers. Three independent readers retrospectively evaluated the sagittal proton density-weighted images of the 24 patients. RESULTS: The articular muscle of the knee was identified in 100% of prospective studies (10/10) and in 83% of retrospective studies (25/30). For the prospective study group, measurements (mean +/- SEM) were as follows: number of bundles, 2.4 +/- 0.68 (range, 1-4); length of uppermost bundle, 47.2 +/- 4.06 mm; width of origin, 8.6 +/- 0.79 mm; angle of origin, 11.4 degree +/- 1.29 degree; and cross-sectional bundle width, 19.8 +/- 2.05 mm2. CONCLUSION: The articular muscle of the knee can usually be identified by MR imaging as an independent entity, separate from the great (vastus) muscle group.

Adolescent↗
PubMed1996

Vertebral fluid collection associated with vertebral collapse.

OBJECTIVE: Three elderly women with osteoporotic compression fractures of a vertebral body underwent MR imaging because of neurologic signs and symptoms. Atypical fluid collections were shown by MR imaging in all three patients. For histologic characterization of these vertebral fluid collections, CT-guided biopsies and aspirations were done for all three patients. CONCLUSION: After studying the clinical, histologic, and imaging features of these fluid collections associated with vertebral fracture, we suggest that they are most likely associated with underlying avascular necrosis.

Aged↗
PubMed1996

Vertebral morphometry derived from digital images.

OBJECTIVE: We describe a method for capturing measurement data directly from digitized images using specialized software and high-resolution workstations. We have evaluated the reliability, accuracy, and reproducibility of this method in an international clinical trial involving vertebral morphometry. MATERIALS AND METHODS: Accuracy was determined using clinical radiographs measured with vernier calipers and a film phantom. Intra- and interobserver variabilities were assessed, and longitudinal reproducibility was evaluated. As part of the trial, spinal radiographs were collected from more than 200 international health care facilities and digitized at four screening centers. Digitized images were stored and sent to our central facility for morphometry and archiving. Timeliness and variability of the process were tracked. RESULTS: Relative accuracy was nearly 100%. Correlation with clinical measurements was high (r = .96; p < .05). The mean coefficient of variation for interobserver variability was 2%. Intraobserver variation was 3-5%. The coefficient of variation for longitudinal reproducibility ranged from 4% to 6%. After 9 months of operation, our trial included 9494 patients. Of approximately 36,000 radiographs, 98% passed quality review. Only 1% of vertebral levels were not measurable. Hardware and software problems were minimal. CONCLUSION: The use of digitized images for morphometry is accurate, reproducible, and convenient. When applied to a large-scale clinical trial, it offers unique advantages that may justify the cost and complexity that exceed those of conventional radiographs.

Female↗
PubMed1994

MR imaging of the thoracic aorta: comparison of spin-echo, angiographic, and breath-hold techniques.

PURPOSE: To compare magnetic resonance (MR) angiography and fast MR imaging with spin-echo (SE) and non-MR imaging techniques in examination of the thoracic aorta. MATERIALS AND METHODS: Eighty-nine patients underwent breath-hold or cine MR angiography; SE was used in 67 patients and fast MR imaging in 28. A comparison was made with non-MR imaging (transthoracic echocardiography in 49 patients, transesophageal echocardiography in 18, and arteriography in 33) findings and those from surgery or autopsy (16 patients). RESULTS: MR angiography enabled differentiation of slow flow from thrombus, demonstrated aortic valve anatomy and aortic regurgitation, and accurately showed anatomy with only one error. It demonstrated two communications, flaps, and three branch stenoses better than SE, which produced some artifacts that mimicked thrombus or flaps. Fast MR imaging often produced artifacts or poor image quality (10 of 28 patients). CONCLUSION: Compared with SE MR imaging, MR angiography provides additional useful anatomic and functional information concerning diseases of the thoracic aorta, usually gained only with echocardiography or arteriography.

Aorta, Thoracic↗
PubMed1992

Spiral CT in evaluation of head and neck lesions: work in progress.

Spiral computed tomography (CT) was used in the evaluation of 21 patients with head and neck lesions. Scanning time ranged from 24 to 36 seconds, and high-quality diagnostic scans with excellent anatomic resolution and minimal motion artifact were produced. Vascular opacification was optimized with substantially less contrast medium than used in conventional studies. These preliminary results show spiral CT to be at least comparable with conventional CT in the evaluation of the head and neck.

Female↗
PubMed1992

Spiral CT of the thorax with reduced volume of contrast material: a comparative study.

The effectiveness of spiral computed tomography (CT) of the thorax performed with 60 mL of 60% contrast material was compared with that of conventional dynamic incremental CT performed with 120 mL of 60% contrast material. Fifty patients in whom contrast material-enhanced thoracic CT examination was necessary were assigned to undergo either spiral CT or dynamic incremental CT. Vascular opacification and mediastinal-lung image quality were graded independently by two observers. Vascular opacification and lung image quality were better with spiral CT than with conventional CT. Results of this pilot study encourage the use of spiral CT to decrease the volume of contrast medium used in patients undergoing thoracic CT.

Adult↗
PubMed1992

Spiral CT of the pancreas.

Computed tomography (CT) is the modality of choice for evaluation of pancreatic disease. In this prospective study, images obtained with spiral CT, which enables examination of a region of the body in a single breath-hold, were compared with those obtained by means of dynamic CT with automatic table incrementation in two groups of 30 patients referred for suspected disease of the pancreas. In both groups, vascular opacification and anatomic detail were analyzed with a grading system (1 = poor, 2 = good, 3 = excellent). Vascular opacification received mean grades of 2.78 and 2.33 in the spiral CT and control groups, respectively. Anatomic detail received mean grades of 2.63 and 2.42 in the spiral CT and control groups, respectively. Respiratory motion artifact was absent in all spiral CT examinations but was present in 17 of 30 control CT examinations. Images obtained with spiral CT showed superior vascular opacification and reduced respiratory artifact with smaller amounts of contrast agent (90 mL vs 120 mL) compared with those obtained with dynamic CT.

Adult↗