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Biomedical subjects

K S Berbaum

Publications and source records attributed to K S Berbaum.

At least 37 records · Page 2Linked to original sources
PubMed1997

Educating interventional radiology personnel in nonpharmacologic analgesia: effect on patients' pain perception.

RATIONALE AND OBJECTIVES: The purpose was to evaluate the effects on patients' pain perception of educating interventional radiology personnel in nonpharmacologic analgesia. MATERIALS AND METHODS: Ninety-six patients undergoing lower-extremity arteriography or percutaneous nephrostomy were asked to rate the pain they experienced during the procedure on a scale of 0 to 5 (0 = no pain, 1 = mild pain, 2 = moderate pain, 3 = severe pain, 4 = very severe pain, 5 = worst pain possible). Patients were studied at two baseline sessions (baseline 1, December 1993 to August 1994, n = 15; and baseline 2, September 1995 to January 1996, n = 11) and after the staff underwent one of two training sessions (posttraining 1, January 1995 to July 1995, n = 34; posttraining 2, January 1996 to April 1996, n = 36). Training targeted nurses and technologists and included rapport skills, correct use of language and suggestions, distraction, relaxation training, and self-hypnosis. Data were evaluated with analysis of variance for repeated measures. RESULTS: The mean pain scores reported after training were lower (1.48) and matched an "acceptable" pain score of 1.52 more closely than those reported under baseline conditions (2.54, P = .001). There was a tendency toward reduced use of intravenously administered agents for conscious sedation after training. There were no statistically significant differences in the pain scores between patients who underwent arteriography and patients who underwent nephrostomy overall (1.76 and 1.78, respectively), at baseline (2.58 and 2.43, respectively), and after staff training (1.49 and 1.42, respectively). CONCLUSION: Interventional radiology personnel trained in nonpharmacologic analgesia methods can help reduce patients' pain perception during interventional procedures.

Analgesia↗
PubMed1997

Teleradiology consultation for a rural hospital: patterns of use.

RATIONALE AND OBJECTIVES: The authors documented quantitatively how teleradiology was used for contemporaneous consultation with a radiologist by physicians at a small rural hospital. MATERIALS AND METHODS: The authors collected 31/2 years worth of data at a small hospital on all patients (n = 327) for whom a radiologist's consultation by teleradiology was requested and compared the data with those from a control group of 309 patients whose studies were interpreted at the same hospital. RESULTS: Teleradiology consultation was requested by the attending physician in 3.6% (519 of 14,586) of all examinations performed during the study period. Physicians requested teleradiology consultation most often for patients with multiple examinations (average 1.59 vs 1.35 for controls). Examinations of infants were 10 times more prevalent in the teleradiology group than in the control group. The indication for most (52%) teleradiology consultations was trauma. Requests for interpretation of spine and abdominal radiographs were relatively more frequent than were those of other studies. CONCLUSION: Physicians in this rural practice used contemporaneous radiologic consultation for selected specific examinations, with emphasis on examinations for trauma, spine, abdomen, and the infant age group.

Adolescent↗
PubMed1997

Pediatric radiology at a rural hospital: value of teleradiology and subspecialty consultation.

OBJECTIVE: We performed a field study and subsequent laboratory investigation of pediatric radiology at a small rural hospital. Our investigation had three components: to describe the characteristics of pediatric radiology in a rural primary care facility, to test the diagnostic accuracy of interpretation of pediatric images transmitted by teleradiology, and to compare relative diagnostic accuracy of general and pediatric radiologists who interpreted pediatric images at a rural institution. MATERIALS AND METHODS: All 196 pediatric radiographs obtained during a 4-month period comprised the database from which we determined practice characteristics. Reports of 153 unselected cases interpreted by general radiologists using teleradiology were compared with interpretation of the same cases by a pediatric radiologist who interpreted the original radiographs. Discrepant cases were further investigated by a receiver-operating-characteristic curve experiment in which general and pediatric radiologists interpreted each case twice: once viewing teleradiologic images and once viewing the original radiographs at another setting. We then compared interpretive accuracy of observers and techniques. RESULTS: The pediatric radiographs were predominantly simple examinations for common acute disease, particularly pneumonia and fractures. Discrepancies of interpretation between teleradiology and original radiographs, which occurred in 13% of images, showed no significant difference in accuracy of interpretation for either teleradiologic images or original radiographs. Likewise, we found no significant advantage for accuracy of interpretation by general or pediatric radiologists. Receiver-operating-characteristic analysis of 18 discrepant cases showed slightly increased accuracy for interpretation of original radiographs by pediatric subspecialists. CONCLUSION: Simple pediatric radiographs obtained at a rural primary care institution and transmitted by teleradiology can be adequately interpreted by general radiologists.

Adolescent↗
PubMed1997

Disorientation and postural ataxia following flight simulation.

BACKGROUND: Motion sickness-like symptoms can afflict pilots training in military simulators. This simulator sickness involves symptoms of gastrointestinal distress, eyestrain and disorientation. A simulator sickness Questionnaire (SSQ) with subscales available for each of these dimensions has been developed to assess the problem. HYPOTHESIS: This study examined the hypothesis that there is a strong correlation between the SSQ subscale which summarized self report of disorientation symptoms and an objective measure of post-simulation postural instability. METHODS: Data from two Navy simulators were analyzed: Device 2F114, a Weapon System Trainer for the A-6E Intruder, and Device 2F143, an Operational Flight Trainer for the EA-6B. Tests of standing and walking unsteadiness were administered along with the Simulator Sickness Questionnaire (SSQ). RESULTS: Significant correlations were found between scores on postural stability tests and the SSQ disorientation subscale scores, but correlations between scores on postural stability tests and the SSQ nausea and oculomotor subscale scores were much weaker and not statistically significant. CONCLUSIONS: These results provide some evidence for the validity of the disorientation subscale of the SSQ and suggest that the postural instability observed after simulator exposure may, in fact, result from disorientation.

Aerospace Medicine↗
PubMed1996

Anatomic distribution of metastases in the vertebral body and modes of hematogenous spread.

STUDY DESIGN: A retrospective review of the magnetic resonance spine examinations of 49 patients with metastatic bone disease to the spine was performed. OBJECTIVES: To determine whether the pattern of metastatic distribution in the spine correlates with the type of primary tumor and theoretical mode of hematogenous spread by arterial or venous routes. SUMMARY OF BACKGROUND DATA: In 1940, Batson theorized a venous plexus route by which tumors spread to the spine from pelvic tumors such as prostatic carcinoma. It this theory is true, the venous vascular anatomy of the spine would result in metastases being deposited in the central or posterior vertebral body, whereas arterial deposits would occur near the end-plates. METHODS: Each vertebral body was divided into 27 equal cells in the magnetic resonance images; the central and posterior cells in the midsagittal view were defined as central, and the other cells were defined as peripheral. The primary tumor was assigned to either the arterial or venous group based on Batson's proposed mode of spread. The average number of lesions per involved vertebral body in the central and peripheral regions was calculated. RESULTS: There was no statistically significant correlation between tumors with proposed arterial/venous routes of metastasis and central/peripheral location of metastatic deposits. CONCLUSION: The mechanism by which tumors spread to the vertebral body may not be via a pure arterial or venous route. Other mechanisms such as tissue specificity, cascade system, and closed loop circulation system may be involved.

Adolescent↗
PubMed1996

Effects of medial and lateral displacement calcaneal osteotomies on tibiotalar joint contact stresses.

Translational calcaneal osteotomies are used clinically to realign the mechanical axis of the lower limb. In this study, the effects of medial and lateral displacements of the posteroinferior fragment on tibiotalar joint contact mechanics were assessed using pressure-sensitive film. Eight osteotomized fresh-frozen cadaver specimens were loaded in each of three testing positions: neutral position (no shift), 1 cm of lateral displacement of the inferior fragment with respect to the superior fragment, and 1 cm of medial displacement of the inferior fragment. For an applied load of 1,330 N, two times body weight, a 1 cm lateral displacement shifted the center of pressure an average of 1.06 mm laterally, whereas a 1 cm medial displacement shifted the center of pressure an average of 1.58 mm medially. While global contact parameters (contact area, spatial mean contact stress, and peak local contact stress) were not appreciably altered by osteotomy, regional contact parameters changed in a reproducible and statistically significant manner. Among four nominally equal-sized, parasagittally bounded cartilage zones, lateral displacements consistently unloaded the most medial zone and increased loading of the most lateral zone; medial calcaneal displacements had the converse effect. These cadaver results suggest that translational calcaneal osteotomies may be used clinically to partially offload focal areas of cartilage along the medial and lateral borders of the tibiotalar joint.

Ankle Joint↗
PubMed1996

1996 AUR Memorial Award. Densitometric analysis of eccentric vascular stenoses: comparison of CO2 and iodinated contrast media.

RATIONALE AND OBJECTIVES: The authors compared the accuracies of CO2 and iodinated contrast material in the densitometric quantification of eccentric vascular stenoses. METHODS: Five precision-machined eccentric phantom stenoses of 50%, 60%, 70%, 80%, and 90% cross-sectional area narrowing were integrated into a pulsatile ex vivo flow model, imaged with digital subtraction angiography (DSA), and analyzed with densitometry. Relationships between the actual and measured (densitometric) degree of cross-sectional area narrowing were evaluated by using linear regression analysis and paired Student t tests. Comparison measurements were obtained in en face and profile projections. In addition, the effect of iodinated contrast material concentration was evaluated over a range of dilutions (47-282 mg iodine per milliliter). RESULTS: CO2 yielded significantly more accurate results than did iodinated contrast material (282 mg iodine per milliliter) in the 50%, 60%, and 70% stenosis models when imaging was performed en face (P < .005). The best overall correlation was observed with CO2 DSA when imaging in profile (slope = 0.91, intercept = 2.42% actual stenosis, r = .99). The accuracy of densitometric stenosis estimation was inversely related to the concentration of iodinated contrast material. CONCLUSION: CO2 DSA densitometry, under the conditions of these experiments, yields quantitative measures of relative cross-sectional area narrowing that are comparable with, and under some circumstances surpass, those obtained with iodinated contrast material-based DSA. In this model, CO2 was more useful than iodinated contrast material in 50%-70% stenosis when imaging in the least-optimal plane of stenosis quantification, the en face projection.

Absorptiometry, Photon↗
PubMed1996

Cause of satisfaction of search effects in contrast studies of the abdomen.

RATIONALE AND OBJECTIVES: Extraintestinal abnormalities visible without contrast material on abdominal radiographs are reported less frequently when contrast examinations are performed. Gaze dwell time was used to determine whether this difference is due to failure by observers to scan plain-film regions of contrast studies or discounting of plain-film abnormalities that were actually scanned. METHODS: Patients were included whose contrast studies had elicited the largest reductions in positive responses compared with their plain-film studies in a previous detection experiment. Gaze of 10 radiologists was studied. RESULTS: Significantly less time was spent gazing at non-contrast regions of contrast examinations than at the corresponding regions of radiographs. Errors with radiographs were based primarily on failures of recognition and decision making, whereas errors with contrast studies were based primarily on faulty scanning. CONCLUSION: Satisfaction of search errors on contrast examinations are caused by reduction in scanning of noncontrast regions.

Contrast Media↗
PubMed1996

Coronal plane rotation of the first metatarsal.

A method for measuring first metatarsal rotation on weightbearing tangential radiographs is described. Under controlled conditions using cadaver specimens, 5 degree changes in first metatarsal rotation were associated with a mean change in radiographically measured rotation of 5.4 degrees (SD = 1.7 degrees). A clinical study of 30 hallux valgus and 30 control patients was undertaken to assess the reliability of the method of measurement. The overall reliability was high for both hallux valgus and control patients (r = 0.93 and 0.95, respectively). In these two groups, no significant difference was found between the mean values for first metatarsal rotation. Likewise, we found no correlation between first metatarsal rotation measured on tangential standing ("sesamoid" view) radiographs and the first metatarsophalangeal angle or the intermetatarsal 1-2 angle measured on anteroposterior standing radiographs.

Analysis of Variance↗
PubMed1996

Subspecialty radiology consultation by interactive telemedicine.

This investigation tested the hypothesis that interactive, low-resolution telemedicine is an effective method for radiologists' consultations. The case material consisted of radiographs and digital images from patients with 14 paediatric diseases readily diagnosed by imaging, and 10 matched controls. The original images were first evaluated by a general radiologist, who entered a diagnosis. He or she then discussed the case with a paediatric radiologist who had access to the same images via low-resolution interactive video. Following the consultation the general radiologist could change diagnosis. The experimental subjects were three teams of general and paediatric radiologists. Observer-performance and case-comparison methods were used for analysis. The results showed that the general radiologists' diagnostic accuracy improved after telemedicine consultation with the subspecialist, the area under the ROC curve improving from 0.648 to 0.709. The interactive consultation was judged valuable by all participants. We conclude that low-resolution interactive telemedicine is of value for consultation between generalists and subspecialists in radiology.

Humans↗
PubMed1996

MR imaging of anterior cruciate ligament injury: independent value of primary and secondary signs.

OBJECTIVE: The purpose of this blinded study was to test the value of primary and secondary signs, independent of each other, for diagnosis of a tear of the anterior cruciate ligament (ACL) by means of MR imaging. MATERIALS AND METHODS: MR images of the knee in 74 patients who had the status of the ACL confirmed arthroscopically were blindly reviewed for status of the ACL three times: with primary signs masked, with secondary signs masked, and with no signs masked. On the basis of the observed signs at each session, the status of the ACL was predicted and the confidence in that prediction was noted. The MR imaging predictions were compared with the arthroscopic findings. The results were analyzed with receiver operating characteristic curves and stepwise discriminant analysis. RESULTS: We found no difference in diagnostic performance when only primary signs were used and when both primary and secondary signs were used. When using primary signs only, our observers performed significantly better than when using secondary signs alone. However, with secondary signs alone, our observers performed better than if left to chance for predicting ACL status. Of the secondary signs, our statistical analysis found bone contusion, anterior translation of the tibia, and an uncovered posterior horn of the lateral meniscus to be the most useful for diagnosis. CONCLUSION: Secondary signs do have value for deciding ACL status independent of primary signs. However, our observers performed much better when using primary signs instead of secondary signs. In the clinical setting, secondary signs do not help significantly in the diagnosis of ACL tears by means of MR imaging.

Anterior Cruciate Ligament↗
PubMed1996

Diagnosing left lower lobe pneumonia: usefulness of the 'spine sign' on lateral chest radiographs.

BACKGROUND: Left lower lobe pneumonia may be obscured by the heart on the postero-anterior (PA) chest radiograph. In such cases, the lateral projection may be helpful, especially if it exhibits the "spine sign", which is an interruption in the progressive increase in lucency of the vertebral bodies from superior to inferior. We investigated whether the spine sign would help family physicians diagnose left lower lobe pneumonia on chest radiographs. METHODS: We selected the chest radiographs of all patients with left lower lobe pneumonia who were seen between 1983 and 1995 at a family practice training program (N = 78) and an equal number of chest radiographs of patients without pneumonia. Six family physicians read these radiographs under two viewing conditions: PA only vs PA and lateral. We used receiver operating characteristic (ROC) curve methodology to compare the two viewing conditions. RESULTS: There was no significant difference in performance between the two viewing conditions. The lateral view was helpful in some patients but misleading in others. Among patients with pneumonia, the lateral view was helpful when the spine sign was present, but it was misleading when the spine sign was absent. CONCLUSIONS: In this study of family physicians, the lateral chest radiograph did not improve overall diagnostic accuracy in patients with left lower lobe pneumonia. Among pneumonia patients with the spine sign, however, the lateral view was often helpful.

Adolescent↗
PubMed1995

Degeneracy and discrete receiver operating characteristic rating data.

RATIONALE AND OBJECTIVES: Observer performance studies sometimes use too few cases for estimating diagnostic accuracy from binormal receiver operating characteristic (ROC) curves. One important problem is degenerate data sets. We compared a new algorithm, RSCORE4, with the exact-solution approach to degeneracy in ROCFIT and with the Wilcoxon statistic. METHODS: Degenerate ROC solutions result from empty cells in the data matrix. We addressed this problem by adding a small constant to empty cells in a maximum-likelihood program, RSCORE4. When this method failed, the program branched to a pattern-search algorithm. We tested the program in a series of Monte Carlo studies. RESULTS: RSCORE4 converged to nondegenerate solutions in every case and gave results closer to population values than ROCFIT or Wilcoxon. ROCFIT converged to exact-fit degenerate solutions, those with zero or infinite parameter values, in more than 40% of the samples. The Wilcoxon statistic was biased. CONCLUSION: RSCORE4 seems to outperform other currently recommended methods for dealing with degeneracy.

Algorithms↗
PubMed1995

Multireader, multicase receiver operating characteristic methodology: a bootstrap analysis.

RATIONALE AND OBJECTIVES: We evaluated by bootstrapping the conclusions obtained by the Dorfman-Berbaum-Metz (DBM) receiver operating characteristic (ROC) method and by the Toledano-Gatsonis (TG) method on a well-known data set. METHODS: We bootstrapped in two ways, resampled cases while holding readers fixed and resampled both cases and readers. RESULTS: When an analysis of variance of pseudovalues implies that reader variance and all random interactions with treatment are essentially zero, then case-resampling bootstrap and the DBM and TG methods should give the same results. Case-resampling bootstrap and the DBM and TG methods did give highly similar results for both individual readers and the averages over all readers. Both the case-resampling bootstrap and the reader-case resampling bootstrap gave smaller standard errors for group than for individual reader means, thereby providing evidence for a trade-off of readers and cases with regard to precision and power in this data set. CONCLUSION: Case-resampling bootstrap provides some justification for the DBM and TG methods.

Analysis of Variance↗
PubMed1995

Added value of radiologist consultation to family practitioners in the outpatient setting.

PURPOSE: To measure the added value of a radiologist's consultation to the interpretation of radiographs previously read by a family practitioner. MATERIALS AND METHODS: The authors reviewed 1,674 chest and extremity radiographs previously read by a family practitioner and consulting radiologist. The 196 radiographs in which there was a discrepancy between the family practitioner's and radiologist's report were evaluated by a radiologist and family physician not involved in and blinded to the original interpretations. The overall accuracy of the participants was determined and differences statistically quantified. RESULTS: The overall sensitivity of the radiologists was greater than that of the family practitioners (92% vs 86%); specificity was not significantly different. For extremity examinations, there were no significant differences in accuracy of the radiologists and family practitioners; the sensitivity of radiologists for chest studies was considerably greater (89% vs 80%). Radiologic consultation was of particular value in the detection of pneumonia and masses. CONCLUSION: At a family practice center, the radiologist's role for extremity radiographs might be limited to individual consultation, with review of all chest radiographs.

Ambulatory Care↗
PubMed1995

Haustral septations increase axial and radial distribution of luminal contents in glass models of the colon.

We used two glass models of the colon to test the hypothesis that luminal septations increase efficiency of flow. Each was a straight glass tube 4 cm in diameter and filled with water. One had four septations narrowing the lumen to 2 cm; the other had no septations. For each run, liquid dye and one solid test particle were placed at one end of the model. A single pressure pulse was applied to the dye and particle. The distance each traveled was compared using analysis of variance. The nonseptated model had poor mixing of dye, and the particle moved only short distances. In the septated model, there was thorough mixing of dye and the particle moved rapidly along what appeared as a central core of high-velocity liquid flow from one septal opening to another. Compared with the nonseptated model, this produced statistically significant increases in the distances traveled by means of 32 (dye) and 90% (particle). Our studies suggest that septations in a tubular organ facilitate intraluminal mixing and flow of liquids and solids.

Colon↗
PubMed1995

Teleradiology for rural hospitals: analysis of a field study.

We compared the accuracy of a low-cost teleradiology system with plain film at a small rural hospital. The comparison was a case-control, paired-comparison study. In total 377 consecutive cases were read prospectively by teleradiology and later by independent interpretation of the plain films. 'Truth' was determined in discrepant cases by further investigation of available records and images. Sensitivity and specificity were determined for each modality, and agreement using the kappa statistic. There was 90% agreement between teleradiology and plain film, with no significant differences. Sensitivities (0.88, 0.89) and specificities (0.98, 0.98) of the two methods were almost identical. McNemar's test indicated no significant differences in the accuracy of the two modalities. We conclude that inexpensive teleradiology for small rural hospitals is equivalent to plain film for radiologists' interpretation.

Case-Control Studies↗