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PubMed1999

Further study of the control of place cell firing by intra-apparatus objects.

The angular positions of hippocampal place cell firing fields are accurately controlled by the position of a single salient cue card attached to the wall of a recording cylinder; when the card is rotated, fields rotate equally. In contrast, the control exerted by 3-dimensional objects placed directly in the recording arena depends on their arrangement. When three objects lie on the vertices of an isosceles triangle near the center of the cylinder they rarely exert any control over the angular positions of firing fields. However, if the isosceles triangle is dilated so that its vertices are against the apparatus wall, the objects exert virtually ideal control over angular field position. Why do the objects gain control when they are against the cylinder wall? One possibility is that the asymmetry in the object set is more easily detected when the objects are far apart so that they provide a better polarizing cue. This hypothesis assumes that the identity of individual landmarks is not recognized by the place cell system whereas their geometric arrangement provides crucial information for controlling place field positions. If this is true, putting the 3 objects against the cylinder wall on the vertices of an equilateral triangle should cause a loss of stimulus control over the angular positions of firing fields. To the contrary, we found that the firing fields of most place cells (23/29) were accurately controlled by the equilateral object arrangement. Moreover, 5/6 of the uncontrolled cells were in a single animal. These results bolster our previous suggestion that the centrally placed objects fail to control place field positions because the computations necessary to form a stable reference frame are very difficult when the animal can go between stimuli.

Action Potentials↗
PubMed2004

Shape-based recognition of wiry objects.

We present an approach to the recognition of complex-shaped objects in cluttered environments based on edge information. We first use example images of a target object in typical environments to train a classifier cascade that determines whether edge pixels in an image belong to an instance of the desired object or the clutter. Presented with a novel image, we use the cascade to discard clutter edge pixels and group the object edge pixels into overall detections of the object. The features used for the edge pixel classification are localized, sparse edge density operations. Experiments validate the effectiveness of the technique for recognition of a set of complex objects in a variety of cluttered indoor scenes under arbitrary out-of-image-plane rotation. Furthermore, our experiments suggest that the technique is robust to variations between training and testing environments and is efficient at runtime.

Journal Article↗
PubMed2000

Object-based visual attention with endogenous orienting.

In a series of experiments, we examined covert orienting using endogenous cuing, in which attention is voluntarily directed toward a peripheral location. In one experiment, subjects were cued to attend to one end of an oblong object. They then detected targets on the cued object or elsewhere. In another experiment, subjects provided judgments of the relative temporal order of two flashes after their attention had moved endogenously. In a third experiment, subjects were directed to attend to an empty spatial location and subsequently discriminated features of objects that appeared at or near the locus of attention. In each of these situations, attentional orienting was object based, in the sense that nonattended locations that were on the cued object had an advantage over nonattended locations that were not on the object. The results are discussed in terms of their implications for object-based representations and the differences between exogenous and endogenous orienting of attention.

Attention↗
PubMed1996

Spatial constructions by capuchin monkeys.

Spontaneous object grouping by two capuchin monkeys (Cebus apella) ranging from 1 to 4 years of age was investigated. Subjects' spontaneous interactions with groups of objects were recorded. Similarly to human infants and chimpanzees, capuchins increased with age the size of groups, the rate of vertical constructions, and of contemporaneous groups, i.e., of groups made simultaneously or close to another. However, capuchins lagged behind human infants and, partly, to chimpanzees in that they failed to develop alignments of objects, or spatial correspondences between contemporaneous groups. Capuchins' constructive processes were similar to those of chimpanzees and different from those of human infants. Nonhuman primates increasingly manipulate objects together with the same part of their body. In these instances, no specific spatial relations among objects as detached units are detectable. In fact, objects are related to one another only incidentally to the simultaneous relations of each object to the self. Therefore, nonhuman primates increasingly manipulate objects in relation to their body.

Age Factors↗
PubMed1990

Electrophysiological evidence for visual-vestibular interaction in man.

The aim of the experiments reported here was to confirm electrophysiologically the results of psychophysical experiments, which demonstrated that thresholds for object-motion detection are significantly raised during both concurrent active or passive sinusoidal head oscillations and during visually induced self-motion perception (circularvection, CV). This intersensory inhibition could now be demonstrated electrophysiologically by recording visual motion evoked potentials both during concurrent sinusoidal head oscillations and during visually induced apparent self-motion of the objectively stationary subject. Recordings of visual contrast reversal evoked potentials failed to reveal such an interaction. Perceptual phenomena with multisensory stimulation are well described in the literature. Berthoz et al. demonstrated the dominant influence of the visual channel on vestibular thresholds such that the detection of a suprathreshold vestibular stimulation was clearly impaired by a simultaneously moving visual pattern inducing linearvection and vice versa. Comparable results are reported for circularvection. Evidence for inhibitory interaction between object-motion and simultaneous self-motion perception also exists. Electrophysiological data on intersensory interaction in humans have only been reported between electrical stimulation of a limb and its concurrent movement by means of scalp-recorded somatosensory-evoked potentials (SSEPs) (e.g. refs. 3, 5). Electrophysiological evidence for the interaction of visual object-motion and vestibular self-motion perception in humans has never been reported in the literature thus far, though Hood and Kayan demonstrated that retinal image motion makes a contribution to the vestibularly evoked bioelectric response.

Adult↗
PubMed1997

Congenital malformations in offspring of women with hyperglycemia first detected during pregnancy.

OBJECTIVES: Our aim was to determine risk factors for congenital malformations in offspring of women with hyperglycemia first detected during pregnancy (i.e., women with gestational diabetes). STUDY DESIGN: A total of 3743 pregnancies complicated by gestational diabetes mellitus delivered at > 20 weeks of gestation were reviewed for the presence of congenital malformations diagnosed before hospital discharge. Anomalies were categorized as major, minor, or absent. Pregnancies with genetic syndromes and aneuploidies were excluded. In addition to maternal clinical and historic parameters, diagnostic glycemic parameters (fasting and post-glucose-challenge levels from the diagnostic glucose tolerance test, highest fasting serum glucose level, and hemoglobin A1c level before insulin therapy) were examined by logistic regression for predictive risk of major anomalies. RESULTS: One or more major congenital anomalies were present in 108 (2.9%) of the newborns; an additional 91 (2.4%) had only minor anomalies. None of the maternal variables were associated with the risk of minor anomalies. By contrast, parity, a history of gestational diabetes mellitus, and several glycemic parameters were associated with the risk of major anomalies. The highest fasting serum glucose level was the best independent predictor (odds ratio 1.13/10 mg/dl, 95% confidence interval 1.09 to 1.34). The fasting serum glucose level at diagnosis, a parameter that is almost uniformly available to clinicians, gave similar predictive information about the risk of major anomalies (odds ratio 1.13, 95% confidence interval 1.08 to 1.14). Stratification of women into subgroups of fasting serum glucose level at diagnosis revealed the incidence of major anomalies to be as follows: 2.1% with a fasting serum glucose level < 120 mg/dl (2973 pregnancies), 5.2% with a fasting serum glucose level of 121 to 260 mg/dl (747 pregnancies), and 30.4% with a fasting serum glucose level > 260 mg/dl (23 pregnancies). CONCLUSION: In a large population of women without a diagnosis of diabetes before pregnancy, the maternal fasting serum glucose concentration at diagnosis was a useful predictor of the risk of major but not minor anomalies. The rate of major anomalies doubled with a fasting glucose level > 120 mg/dl. Thus a fasting glucose level below that of overt diabetes outside of pregnancy carries an important risk of major anomalies that must be considered in the counseling and management of these patients.

Adult↗
PubMed1995

Rheumatoid arthritis of the craniocervical region by MR imaging: detection and characterization.

OBJECTIVE: The purpose of our study was to evaluate the potential of contrast-enhanced MR imaging to detect and to characterize craniocervical rheumatoid arthritis in a large population group, to compare MR imaging with clinical and conventional radiographic findings, and to examine the relationship between the histopathologic and MR imaging findings in seven patients. SUBJECTS AND METHODS: We performed contrast-enhanced MR imaging using T2-weighted gradient-echo sequences and T1-weighted spin-echo sequences in 136 patients with rheumatoid arthritis. Sequential T1-weighted images were obtained before, 3 min after, and 15 min after injection of contrast material. Plain films were acquired in all patients. Serologic status and neurologic status were determined in each patient within 2 days of MR imaging. Patients were categorized into one of four groups, depending upon whether they had joint effusion, hypervascular pannus, hypovascular pannus, or fibrous pannus according to signal patterns on contrast-enhanced MR images. Signal intensity was measured to assess the enhancement of synovial hypertrophy, joint capsule, joint effusion, and the various stages of pannus tissue. Histologic specimens were obtained from seven patients and were correlated with MR imaging findings. RESULTS: Acute and chronic synovitis were differentiated with contrast-enhanced MR imaging as follows: joint effusion (n = 29), hypervascular pannus (n = 54), hypovascular pannus tissue (n = 8), and fibrous pannus (n = 22). Signal intensity differed significantly among the four groups on contrast-enhanced T1-weighted images. In 59 patients with effusion or hypervascular pannus tissue, atlantoaxial subluxation was diagnosed with plain films. Patients with negative findings on radiographic studies (n = 20) had joint effusion, hypervascular pannus tissue, hypovascular pannus formation, or fibrous pannus tissue on MR imaging studies. Cord compression was found in 10% of all cases and isolated sac compression in 16%. Neurologic findings showed no correlation with MR imaging features. CONCLUSION: Contrast-enhanced T1-weighted spin-echo MR imaging can discriminate between joint effusion and various forms of pannus in patients with rheumatoid arthritis of the craniocervical region. MR imaging also can detect joint effusion and pannus tissue in patients with negative radiographic findings. No relationship between MR imaging findings and clinical symptoms were found. Tissue enhancement and histopathologic findings correlated in a limited number of autopsies.

Acute Disease↗
PubMed1997

Evaluation of different protocols for prostaglandin synchronization to improve reproductive performance in dairy herds with low estrus detection efficiency.

The objective of this study was to evaluate different PGF2 alpha protocols against control protocols for herds with estrus detection efficiencies of 35, 55, and 75% using modeling and simulation: 1) PGF2 alpha treatments based on the presence of a corpus luteum diagnosed by rectal palpation, 2) PGF2 alpha treatments based on the presence of a corpus luteum diagnosed by an on-farm milk progesterone enzyme immunoassay, and 3) PGF2 alpha treatments based on a 14-d fixed treatment schedule without prior screening for ovarian status. After the start of each protocol, estrus detection efficiency was 75% for 7 d after treatment and 35 or 0% for the following week. For the third protocol, an additional modification at estrus detection efficiencies of 85 and 55%, respectively, in the 1st and 2nd wk after treatment was evaluated to establish a protocol for best case assumptions. All protocols improved reproductive performance relative to that of controls with estrus detection efficiencies of 35 and 55%. The mean number of days open was reduced from 124.3 d in the control herd to 95.9, 95.0, and 92.7 for the protocols based on rectal palpation, milk progesterone test, and the fixed treatment schedule, respectively. The protocols based on a fixed treatment schedule were superior to protocols based on rectal palpation and on-farm milk progesterone tests and resulted in better reproductive performance and a higher increase in net return per cow per year. Relative to a control herd with an estrus detection efficiency of 55%, it was cost effective to spend up to $10 per dose of PGF2 alpha, $9 per milk progesterone test, and $6 per rectal palpation.

Animals↗
PubMedDate not supplied

Rapid computed tomography technique to measure ventricular volumes in the child with suspected ventriculoperitoneal shunt failure II. Clinical application.

OBJECTIVES: Assessment of ventricular volume change is critical in the child with suspected shunt failure. Minimal increases may represent high pressures in the child with reduced ventricular compliance but are difficult to detect subjectively. Objective techniques described limit anatomic sampling and are time intensive. The purpose of this study was to develop a rapid technique to measure ventricular volumes in children with suspected shunt failure. METHODS: Ventricular volumes were calculated in 12 children with baseline and emergent computed tomography scans performed for suspected shunt failure. Volumes and percent interval changes were correlated with clinical course. Two observers performed the volume analysis blinded to the clinical information; 1 observer performed the analysis twice. Time to perform the analysis was recorded for 5 studies. RESULTS: The intraobserver and interobserver correlation coefficients were 0.99 and 0.96/0.97, respectively. The mean time to perform the analysis was 2 minutes 42 seconds. Median percent change in patients with and without shunt obstruction was +50% (range: +24%-+367%) and +2% (range: -22%-+36%), respectively. Among patients subjectively read as having stable ventricular sizes, volume changes of -11% to +32% were calculated. CONCLUSIONS: The technique has excellent intra- and interobserver correlation and is rapidly performed. The range of percent volume changes between patients with and without shunt malfunction overlaps. Subjective assessment of ventricular changes is significantly less sensitive than the volume calculation technique. The technique may be most useful in patients with decreased ventricular compliance in whom small interval changes may represent large pressure increases.

Adolescent↗
PubMed2000

A Cryo-TEM Study of Protein-Surfactant Gels and Solutions.

Oppositely charged globular protein and surfactant systems, such as lysozyme-sodium dodecyl sulfate (SDS) and ovalbumin-dodecyltrimethylammonium chloride (DOTAC) form precipitate, gel, and colorless solution in water over a wide concentration range. Bluish solutions are also recognized in connection with the redissolution of precipitate as well as prior to the gel formation. For the lysozyme-SDS system the bluish solution has been suggested to consist of finely dispersed gel particles in solution. The oppositely charged bovine serum albumin (BSA)-DOTAC-water system forms only a large, clear solution phase and a narrow, bluish solution region within a very limited surfactant concentration range. In the lysozyme-SDS system the formation of protein-surfactant aggregates and their growth and breakdown are studied in detail by cryogenic-transmission electron microscopy (cryo-TEM) method. In particular a series of samples with an increased surfactant concentration at fixed 4 wt% of lysozyme is studied. Imaging of the bluish solution at different protein concentrations exhibits large aggregates in the form of rod-like, sheet-like, and star-like objects which are attributed to the gel. At excess amounts of SDS, in the colorless solution, only small objects are detected. In the ovalbumin-DOTAC-water and BSA-DOTAC-water systems large aggregates are also observed in the bluish solutions. Colorless solutions for these two systems show the presence of small objects in the cryo-TEM micrographs. Ultrathin sections of the lysozyme and ovalbumin gels fixed with OsO(4) also show the presence of aggregated structures as judged from the transmission electron microscopy observations. Copyright 2000 Academic Press.

Journal Article↗
PubMedDate not supplied

Distance and shape: perception of the 3-dimensional world by weakly electric fish.

Weakly electric fish orient at night in complete darkness by employing their active electrolocation system. They emit short electric signals and perceive the consequences of these emissions with epidermal electroreceptors. Objects are detected by analyzing the electric images which they project onto the animal's electroreceptive skin surface. This process corresponds to similar processes during vision, where visual images are cast onto the retinas of eyes. Behavioral experiments have shown that electric fish can measure the distance of objects during active electrolocation, thus possessing three-dimensional depth perception of their surroundings. The fundamental mechanism for distance determination differs from stereopsis used during vision by two-eyed animals, but resembles some supplementary mechanisms for distance deduction in humans. Weakly electric fish can also perceive the three-dimensional shape of objects. The fish can learn to identify certain objects and discriminate them from all other objects. In addition, they spontaneously categorize objects according to their shapes and not according to object size or material properties. There is good evidence that some fundamental types of perceptional invariances during visual object recognition in humans are also found in electric fish during active electrolocation. These include size invariance (maybe including size constancy), rotational invariance, and translational invariance. The mechanisms of shape detection during electrolocation are still unknown, and their discoveries require additional experiments.

Animals↗
PubMed2005

[Zinc content analysis in serum, seminal plasma and spermatozoa of asthenozoospermic and oligoasthenozoospermic patients].

OBJECTIVE: To detect the zinc content in serum, seminal plasma and spermatozoa of asthenozoospermic and oligoasthenozoospermic patients, and analyse the relationship between zinc changes and sperm density as well as sperm motility. METHODS: Sperm quality analysis was made according to the WHO standard of Laboratory Manual for the Examination of Human Semen and Sperm-cervical Mucus Interaction (4th edition), and then 90 asthenozoospermic patients, 60 oligoasthenozoospermic patients and 20 fertile men with normal sperm quality were screened out as the objects to be researched. The zinc content in their blood, seminal plasma and spermatozoa was detected by flame atomic absorption spectroscopy. And then a statistical analysis was made on the test results. RESULTS: The blood zinc content among the 3 groups had no significant difference; the seminal plasma zinc of asthenozoospermic and oligoasthenozoospermic patients were significantly lower than that of fertile men (P < 0.05); the spermatozoa zinc content of oligoasthenozoospermic patients was significantly higher than that of asthenozoospermic patients and fertile men (P < 0.01), respectively. CONCLUSION: There may be a positive relationship between the feebleness of sperm production and motility of asthenozoospermic and oligoasthenozoospermic patients and the lower content of seminal plasma zinc; however, the relationship between the higher spermatozoa zinc content and the function of sperm production and sperm motility is still not clear, on which a further study should be made.

Adult↗
PubMed1999

Digital mammography: comparison of adaptive and nonadaptive CAD methods for mass detection.

RATIONALE AND OBJECTIVES: The authors compared the performance of adaptive and nonadaptive computer-aided diagnostic (CAD) methods for breast mass detection with digital mammography. MATERIALS AND METHODS: Both adaptive and nonadaptive modular CAD methods employed recent advances in multiresolution and mutiorientation wavelet transforms for improved feature extraction. The nonadaptive method uses fixed parameters for the image preprocessing modules. The adaptive method, a new class of algorithms, adapts to image content by selecting parameters for the image preprocessing modules within a parameter range. Comparison of the two methods was performed for each individual CAD module with a region-of-interest (ROI) database containing all mass types and normal tissue. RESULTS: Receiver operating characteristic (ROC) analysis clearly demonstrated an improvement in performance for the three adaptive modules and a significant overall difference between the two methods. The average ROC area index (Az) values were 0.86 and 0.95 for the nonadaptive and adaptive methods, respectively. The corresponding P value is .0145. For a previously reported database of full mammographic images containing 50 abnormal cases with all mass types and 50 normal images, the adaptive CAD method had a sensitivity of 96% (1.71 false-positive results per image) compared with 89% (1.91 false-positive results per image) for the nonadaptive CAD method. CONCLUSION: The adaptive CAD method demonstrated better performance. A study is in progress to determine the generalizability of the adaptive CAD method by applying it to larger retrospective image databases with different film digitizers.

Algorithms↗
PubMed2003

Sensitivity of routine intensive care unit surveillance for detecting myocardial ischemia.

OBJECTIVE: To assess the effectiveness of routine intensive care unit surveillance compared with frequent 12-lead electrocardiogram monitoring for detecting electrocardiogram evidence suggestive of prolonged myocardial ischemia in vascular surgery patients. DESIGN: Prospective cohort trial. SETTING: Intensive care unit. PARTICIPANTS: We studied 149 patients undergoing elective infrainguinal or aortic vascular surgery who were admitted to the intensive care unit postoperatively. INTERVENTIONS: Patients were simultaneously monitored with a 10-electrode/12-lead electrocardiogram obtained every 2 mins (criterion standard) and routine intensive care unit surveillance that included standard monitoring (five-electrode/two-lead electrocardiogram with ST segment trends and routine 12-lead electrocardiogram) and clinical assessment for detecting myocardial ischemia. The results of the criterion standard were not available to the caregivers. MEASUREMENTS AND MAIN RESULTS: We measured the ability of routine intensive care unit surveillance to detect the first 20 mins of electrocardiogram evidence suggestive of myocardial ischemia, defined as ST segment depression or elevation of >/=1 mm in two consecutive leads, during the first postoperative day. Seventeen patients (11%) had electrocardiogram evidence suggestive of prolonged myocardial ischemia, the majority of which occurred in leads V2-V4. The sensitivity of routine intensive care unit surveillance for detecting the first episode of electrocardiogram evidence suggestive of prolonged myocardial ischemia in a patient was 12% (95% confidence interval, 7-17%), and the specificity was 98% (95% confidence interval, 95-100%) with a positive predictive value of 40% (95% confidence interval, 32-48%), a negative predictive value of 90% (95% confidence interval, 85-94%), a positive likelihood ratio of 6, and a negative likelihood ratio of 1. The sensitivity of routine intensive care unit surveillance for detecting all episodes was 3% (95% confidence interval, 2-3%) and the specificity 99% (95% confidence interval, 99-100%) per 20-min monitoring interval, with a positive predictive value of 17% (95% confidence interval, 16-18%), negative predictive value of 95% (95% confidence interval, 95-96%), positive likelihood ratio of 3, and negative likelihood ratio of 1. CONCLUSIONS: Routine intensive care unit surveillance has low sensitivity for detecting electrocardiogram evidence suggestive of prolonged myocardial ischemia compared with frequent 12-lead electrocardiograms. Because detecting electrocardiogram evidence suggestive of prolonged postoperative myocardial ischemia is important, physicians should consider alternative strategies to detect myocardial ischemia.

Aged↗
PubMed2006

The use of endoluminal ultrasonography for preventing significant bleeding during endopyelotomy: evaluation of helical computed tomography vs endoluminal ultrasonography for detecting crossing vessels.

OBJECTIVE: To evaluate, in a prospective study, the efficiency of helical computed tomography (CT) and endoluminal ultrasonography (ELUS) for detecting significant crossing vessels, a major cause of bleeding complications when treating patients with pelvi-ureteric junction (PUJ) obstruction, and to compare our results using ELUS with those of an earlier multicentre study (not using ELUS), to see whether the complication rate decreased. PATIENTS AND METHODS: The study included 27 patients with a PUJ who had isotope renography, intravenous urography, helical CT and ELUS before surgery. Depending on the findings of ELUS, patients were treated with a pure lateral Acucise incision (Applied Medical, Irvine, CA, USA) an Acucise with changed cutting direction, or (later) a laparoscopic pyeloplasty. RESULTS: ELUS detected 15% more crossing vessels than helical CT; 16 patients had Acucise (seven lateral, nine other cutting direction), eight were treated with a laparoscopic pyeloplasty and three with other procedures. By contrast with earlier reports and as a consequence of using ELUS, there was no bleeding, vs 16% in the study not using ELUS. The success rate of 73% of the endourological approach is comparable with previous reports. CONCLUSION: ELUS is more sensitive in detecting relevant crossing vessels than helical CT and therefore the use of ELUS can better prevent bleeding complications. ELUS can also improve the success rate by helping in selecting the correct treatment. Because it is minimally invasive and safe, ELUS combined with Acucise (or other possible endourological techniques, like holmium laser incision) should be the first choice of treatment for PUJ stenosis.

Adolescent↗
PubMedDate not supplied

Clinicians' response to computerized detection of infections.

OBJECTIVE: To analyze whether computer-generated reminders about infections could influence clinicians' practice patterns and consequently improve the detection and management of nosocomial infections. DESIGN: The conclusions produced by an expert system developed to detect and manage infections were presented to the attending clinicians in a pediatric hospital to determine whether this information could improve detection and management. Clinician interventions were compared before and after the implementation of the system. MEASUREMENTS: The responses of the clinicians (staff physicians, physician assistants, and nurse practitioners) to the reminders were determined by review of paper medical charts. Main outcome measures were the number of suggestions to treat and manage infections that were followed before and after the implementation of COMPISS (Computerized Pediatric Infection Surveillance System). The clinicians' opinions about the system were assessed by means of a paper questionnaire distributed following the experiment. RESULTS: The results failed to show a statistical difference between the clinicians' treatment strategies before and after implementation of the system (P: > 0.33 for clinicians working in the emergency room and P: > 0.45 for clinicians working in the pediatric intensive care unit). The questionnaire results showed that the respondents appreciated the information presented by the system. CONCLUSION: The computer-generated reminders about infections were unable to influence the practice patterns of clinicians. The methodologic problems that may have contributed to this negative result are discussed.

Cross Infection↗
PubMed2000

Using gray-scale and color and power Doppler sonography to detect prostatic cancer.

OBJECTIVE: We performed a prospective study to assess gray-scale and color and power Doppler sonography for the detection of prostatic cancer and to determine the impact of operator experience. SUBJECTS AND METHODS: Four radiologists with prior experience using gray-scale and Doppler imaging and four urologists with prior experience limited to gray-scale imaging performed sextant biopsies on 251 patients. Each biopsy site was prospectively scored for gray-scale and Doppler abnormality. RESULTS: Cancer was detected in 211 biopsy sites from 85 patients. Overall agreement between sonographic findings and biopsy results as measured with the kappa statistic was minimally superior to chance (kappa = 0.12 for gray-scale, kappa = 0.11 for color Doppler, kappa < or =0.09 for power Doppler). With respect to gray-scale diagnosis of cancer, the performance of radiologists (kappa = 0.12) and urologists (kappa = 0.13) was similar. With respect to power Doppler, the performance of radiologists (kappa = 0.09) was superior to that of urologists (kappa = -0.03, p<0.002). Among patients with at least one positive biopsy for cancer, foci of increased power Doppler flow detected by a radiologist were 4.7 times more likely to contain cancer than adjacent tissues without flow. CONCLUSION: Gray-scale and Doppler imaging did not reveal prostatic cancer with sufficient accuracy to avoid sextant biopsy. Power Doppler may be useful for targeted biopsies when the number of biopsy passes must be limited. There is benefit from increased operator experience with Doppler imaging, but there is no demonstrable benefit of power Doppler over conventional color Doppler sonography.

Adult↗