Analysis of three-dimensional Doppler ultrasonographic quantitative measures for the discrimination of prostate cancer.

OBJECTIVE: The purpose of this study was to determine whether several quantitative ultrasonographic measures have potential to discriminate prostate cancer from normal prostate and to determine the best combination of these measures. The true spatial distributions of cancer within the prostates studied were obtained histologically after radical prostatectomy. The relationship between Doppler ultrasonography and microvessel count was also investigated. METHODS: Three-dimensional Doppler ultrasonographic data were acquired from 39 patients before radical prostatectomy. The removed prostate was sectioned, and whole-mount hematoxylineosin-stained slides were used to identify all regions of cancer within each prostate. These histologic and ultrasonographic data were spatially registered. Doppler ultrasonographic measures were calculated within uniformly sized three-dimensional regions that were either entirely cancerous or noncancerous, and receiver operating characteristic analysis was performed on the results. Microvessel counts were made within each contiguous cancerous region and correlated with ultrasonographic measures. RESULTS: Color pixel density was the best simple measure for discriminating prostate cancer (accuracy, 80%). The mean power mode value (normalized mean power in color pixels) was inversely related to cancer with an accuracy of 1--normalized mean power in color pixels = 65% (low mean power is more cancerous). When color pixel density was combined with the normalized mean power in color pixels, its accuracy improved slightly to 84%. The peak microvessel count had a negative correlation with color pixel density as well as with cancer stage. CONCLUSION: Doppler ultrasonography does provide discriminatory information for prostate cancer, with color pixel density being the most promising measure.

Analysis of three-dimensional ultrasound Doppler for the detection of prostate cancer.

OBJECTIVES: To investigate the relative effectiveness of Doppler ultrasound quantitative measures in discriminating prostate cancer from normal prostate tissue. The true locations of prostate cancer within these prostates were determined by histologic examination after radical prostatectomy. METHODS: Three-dimensional Doppler ultrasound data were acquired from 39 men before radical prostatectomy. The removed prostates were sectioned and all cancerous regions in each prostate were identified on whole-mount hematoxylin-eosin-stained slides. The ultrasound and histologic data were then spatially registered. Biopsy results were simulated on a grid of potential sites within each prostate. Along each simulated biopsy site, the amount of cancer was computed from the hematoxylin-eosin-identified cancerous regions and the peak speed-weighted pixel density (SWD) was compared. RESULTS: By selecting the biopsy sites with higher associated SWDs within each sextant, the probability of having at least one positive biopsy within a prostate increased from 75% if the SWD was ignored to 85% if only the top 15% of potential biopsy sites in each sextant were selected. This trend was seen within each sextant individually as well. CONCLUSIONS: Doppler ultrasound provides discriminatory information for prostate cancer using the SWD. Translating this into a practical strategy that might improve the yield of prostate biopsy remains under development. The results of our study indicate that biopsying regions of high Doppler color could potentially increase the cancer yield to a small degree and improve the accuracy of the biopsy results. These results also objectively verify previous visual studies suggesting a modest improvement with the use of color Doppler.

History of intraoperative ultrasound in neurosurgery.

This article chronicles the development of real-time ultrasound for use in operations in the central nervous system. Described are the technology and the various applications of ultrasound in the neurosurgical operating room. The use of real-time ultrasound to localize, characterize, and instrument lesions of the brain and spinal chord are discussed.

[Prospective and comparative study of pacemaker implants carried out at the electrophysiology laboratory and the operating room]. / Estudio prospectivo, comparativo entre implantes de marcapasos realizados en el laboratorio de electrofisiología y en el quirófano.

INTRODUCTION AND OBJECTIVES: Permanent pacemaker implantation is done by different physicians with either a surgical or clinical training. Our objective was to evaluate if there were significant differences in the implantation parameters and in the complication rate among implantations performed by cardiologists in the electrophysiologic laboratory and cardiological surgeons in the operating room. MATERIAL AND METHODS: We prospectively collected those patients' data who received a first pacemaker implantation by cardiovascular surgeons and electrophysiologists during the year 1998. Data collected included demographic information, indication for pacing, surgical time, complications during procedure, stimulation and sensing thresholds as well as type of pacing. RESULTS: We first-implanted 216 pacemakers in a one year period, 101 by cardiovascular surgeons and 115 by electrophysiologists. 56% were male patients. Average age in the surgery group was 74.2 +/- 9 years and 72.09 +/- 12 in the electrophysiology group (p = NS). Main diagnoses were as follows: complete heart block in 32.9% patients, complete heart block 2. degrees 16.4%, sinus node dysfunction 12.2%, AV node ablation 12.2% and others. The complications rate for surgery group was 4% and 1.7% for electrophysiologists (p = NS). Electrophysiologists placed more bicameral devices. No clinically significant differences were found among other implant parameters. CONCLUSIONS: Pacemaker implant by cardiologists in an electrophysiologists laboratory is a safe procedure that does not have more complications when compared to the same procedure done in the operating room by surgeons. This allows hospital resource optimization and reduction of hospital stay length.

Positive inotropism induced by androgens in isolated left atrium of rat: evidence for a cAMP-dependent transcriptional mechanism.

Steroid hormones exert their biological actions via intracellular receptors modulation of transcription. In addition, a number of molecular interactions, and the existence of membrane receptors in several tissues, support the hypothesis of nongenomic action of steroids. The androgens, 5alpha- and 5beta-dihydrotestosterone (0.1 to 100 microM), induce a rapid positive inotropism in the isolated left atrium of male Wistar rats whose time course of response might suggest that it is a non-genomic effect. However, the fact that the facilitation of contractility was inhibited by actinomycin D (5 microg/ml) and cycloheximide (10 microg/ml) indicates that a transcriptional component might play a role. The existence of a rapid functional genomic role would be somewhat surprising. However, rapid transcriptional mechanisms were also observed in certain cAMP-dependent responses. In the left atrium of rat, Rp-cAMPS (10 microM), a cAMP-dependent protein kinase inhibitor, antagonized 5alpha- but not 5beta-dihydrotestosterone-induced positive inotropism. The inhibition by Rp-cAMPS of isoproterenol- and forskolin-induced positive inotropism, and the fact that these cAMP-dependent effects were also inhibited by actinomycin D and cycloheximide, suggest that a cAMP-dependent transcriptional component may be partly involved in the positive inotropism induced by 5alpha-dihydrotestosterone. In addition, 5alpha-dihydrotestosterone might increase the basal adenylyl cyclase activity by acting on unoccupied beta-adrenoceptor-G-protein-adenylyl cyclase complexes, since the elicited inotropism was inhibited by a beta-blocker, atenolol (1 microM), a G-protein inhibitor, pertussis toxin (2 microg/ml, 3 h), and an adenylyl cyclase inhibitor, dideoxy-adenosine (10 microM).

Frequency analysis of echo texture in tendon.

A texture discriminant based on spatial frequencies is proposed for characterizing B-scans of Achilles' tendon. The anisotropic echo texture of normal tendon has an ellipsoidal spatial spectrum that can be quantified by the ratio of the major-to-minor axis and by the direction of the major axis. Applying a moving window to the B-scan, a corresponding tissue elliptical axis ratio (TEAR) image is derived that segments out tendon. The algorithm was applied to B-scan images taken from 13 volunteers, 6 of whom had tendon abnormalities: tendon rupture (n = 3) or cholesterol deposits (xanthomas) in patients with heterozygous familial hypercholesterolemia (n = 3). The average TEAR value was 1.75 +/- 0.17 for normal tendon, 1.04 +/- 0.06 for torn tendon, and 1.31 +/- 0.16 for tendons with xanthomas. The dispersion of the directionality vectors was used to further differentiate tendons with xanthomas from normal tendons. This technique appears to be useful for characterizing both diffuse and focal tendon abnormalities.

Role of genomic mechanisms on cAMP-dependent positive inotropism in isolated left atrium of rat.

It is well known that beta-adrenoceptor stimulation induces positive inotropism by cAMP-dependent phosphorylation of cardiac calcium channels. Furthermore, hypertrophy of different tissues including the heart have been related to the stimulation of these adrenoceptors via mechanisms coupled to activation of transcription and protein synthesis. Early effects of isoproterenol mediated via this pathway has also been associated to the stimulation of beta-adrenoceptors. However, the effects on the inotropism through genomic mechanisms have not yet been described. Isoproterenol (3 nM to 3 microM) induced a concentration-dependent positive inotropism, in isolated left atrium of male Wistar rats electrically stimulated (0.5 Hz, 5 ms, 30-50% above the threshold voltage), which was antagonized by atenolol (1 microM) and inhibited by a protein kinase A inhibitor, (R)p-cAMPS (10 microM). The inhibitor of transcription, actinomycin D (4 microM), and the protein synthesis inhibitor, cycloheximide (35.5 microM), significantly decreased the positive inotropism induced by isoproterenol. Forskolin (0.1 to 3 microM), an activator of adenylyl cyclase, induced a concentration-dependent positive inotropism which was also inhibited by (R)p-cAMPS, actinomycin D and cycloheximide. In the left atrium of rat, isoproterenol induced a positive inotropism which seems, at least in part, dependent upon intact transcription and protein synthesis, as suggested by the fact that the response was inhibited by the incubation with actinomycin D and cycloheximide. In addition, this genomic effect seems to be mediated by a cAMP-dependent mechanism. As it was inhibited by a protein kinase A inhibitor ((R)p-cAMPS) and similarly to isoproterenol, the positive inotropism induced by forskolin, which increases cytosolic cAMP, was also inhibited by actinomycin D and cycloheximide.

Transcutaneous interruption of ultrasound contrast agents for blood flow evaluation.

RATIONALE AND OBJECTIVES: The ability to create short boluses in targeted arteries with rapid rise times is limited by the transport of bubbles from the venous to arterial portion of the circulation. Acoustic interruption of contrast agent in arteries may create the short boluses necessary for simple wash-in/wash-out measures of blood flow. METHODS: An ultrasound contrast agent was used with spectral Doppler ultrasound to observe contrast interruption in femoral arteries and VX2 carcinoma in a rabbit model. At an upstream location in the femoral artery, single, sinusoidal ultrasound tone bursts at 1.8 MHz with durations of 0.25 to 1 seconds were applied to interrupt the flow of contrast agent injected intravenously. RESULTS: In VX2 carcinoma, bursts as short as 40 cycles produced contrast interruption lasting only one cardiac cycle within the tumor periphery and I(SPPA) <3 W/cm2 produced measurable interruptions. CONCLUSIONS: Acoustic fields applied transcutaneously interrupted flow of contrast agents to form temporally short negative boluses.

3-D color Doppler image quantification of breast masses.

In this article, new measures obtained from color Doppler images are introduced and a pilot study is described, in which these and previously published indices are evaluated for use in future work. Twenty women with breast masses observed on mammography and going to surgical biopsy were studied. Of the masses, 11 proved to be benign and 9 were malignant. Both 3-D mean frequency shift (f-CDI) and power mode Doppler (p-CDI) imaging were performed. To identify the mass and other regions of interest, vessels were displayed as rotatable 3-D color volumes, superimposed on selectable grey-scale/color flow slices. Doppler signals were recorded in each of 6 ellipsoidal regions of interest in and around the mass and 2 in normal tissues. Seven measures were computed in each region, three from power mode, two from mean frequency and two from combinations of both. Radiologists rated the grey-scale appearances of the masses on a scale of 1 to 5 (5=most suspicious) for each of 6 conventional grey-scale criteria. Of the individual vascularity measures in individual ROIs, the log speed-weighted pixel density and log power-weighted pixel density in the lesion internal periphery showed the greatest discrimination of malignancy, although neither was statistically significant nor as good as the peak variables described below. The mean visual grey-scale rating was the best discriminator overall, but two peak vascularity measures each made promising scatterplots in conjunction with the average visual grey-scale rating. These two vascularity measures were the log peak normalized power-weighted pixel density (peak NPD) and log of peak mean Doppler frequency times the peak NPD (vM x NPD(M)). Each of these two values was the maximum in any one of the five chosen ROIs closely associated with the mass. A possible rationale for the relative success of these peak values is the blood signal's normalization and the inhomogeneity of most breast cancers and the expectation that the highest velocities (shunting) and largest collections of blood are not necessarily in the same region in and around the tumor. Peak NPD of cancers varied with age, decreasing by a factor of 45 from 33 to 77 y.

[Coronary spasm and heart arrest caused by ventricular fibrillation]. / Espasmo coronario y parada cardíaca por fibrilación ventricular.

We report the cases of three young men, heavy smokers, without previous heart disease and who were resuscitated after cardiac arrest due to ventricular fibrillation attributed to coronary spasm. All of them complained of atypical chest pain and the exercise testing, echocardiogram and coronary angiography were normal. The first case was diagnosed by Holter monitoring and by provocative testing with intracoronary ergonovine; the second by provocative testing with intracoronary acetylcholine and the third by Holter monitoring. The patients were treated with a calcium antagonist and/or nitrates and in the follow up they remained asymptomatic.

Lupus nephritis: predictive value of conventional and Doppler US and comparison with serologic and biopsy parameters.

PURPOSE: To compare conventional and Doppler ultrasound (US) with clinical and biopsy parameters used to assess disease activity and outcome in lupus nephritis and to assess the predictive value of US. MATERIALS AND METHODS: Thirty-four patients with lupus nephritis prospectively underwent laboratory and US analysis at the time of renal biopsy. US parameters were renal length, relative echogenicity, and resistive index (RI). Laboratory parameters were serum creatinine level, urinary protein level, and serum markers of disease activity. Biopsy parameters were activity index, chronicity index, and assessment of the tubulointerstitium of the kidney. Follow-up data were obtained in all patients for at least 1 year. RESULTS: Ten patients with elevated RI (>0.70) had significantly (P <.05) higher chronicity indexes and creatinine levels than the 24 patients with a more normal RI. RI correlated significantly (P <.05) with creatinine level, chronicity index, and presence of interstitial disease. Only RI and chronicity index were statistically significant predictors of a poor renal outcome. Abnormalities at conventional US were not predictive of renal outcome. A normal RI predicted a better renal outcome whether or not creatinine level was elevated. CONCLUSION: Renal Doppler US may be of greatest clinical utility when its results are apparently discordant with renal functional assessment by allowing identification of patients with higher likelihood of subsequent improvement or worsening of renal status.

Renal transplant evaluation with power Doppler sonography.

This study was performed to determine if the marked variation we had previously noted in the power Doppler sonographic appearance of renal transplants correlated with disease, 22 renal transplants were scanned with power Doppler at 5 MHz, with biopsies being taken within 1 h in 17 kidneys and within 48 h in four other kidneys. Biopsy was not performed in one kidney with distal ureteral obstruction. Biopsy results were complex with many coexistent abnormalities; classification was based upon the predominant abnormality. Cortical vascularity was subjectively evaluated as normal, decreased or markedly decreased, and graded as 0, 1 or 2, respectively, and was compared with biopsy results, serum creatinine levels and resistive index. Cortical vascularity gradings were: 0 (12 cases); 1 (7 cases); and 2 (3 cases). The large number of disease categories (cellular rejection, 11 cases; vascular rejection, 5 cases; IgA nephropathy, 1 case; cyclosporin toxicity, 3 cases; obstruction, 1 case; and lupus nephropathy, 1 case) in relation to the number of vascular grades and number of kidneys precluded statistical analysis of cortical vascularity for rejection. However, vascularity did not appear to correlate with rejection, the three severest cases of vascular rejection having normal (grade 0) vascularity. There was no statistically significant correlation of vascular grade with creatinine levels or resistive index. In conclusion, subjective analysis of the power Doppler sonographic appearance of renal transplants does not appear to aid in their evaluation.

The 3D and 2D color flow display of breast masses.

A prospective study was performed in 24 women with breast masses on mammography going on to surgical biopsy. 2D and 3D power mode and frequency shift color flow Doppler scanning and display were compared. Vessels were displayed as rotatable color volumes in 3D, superimposed on gray-scale slices. The latter were stepped sequentially through the imaged volume. Radiologists rated the masses in each display (3D, 2D and videotapes) on a scale of 1 to 5 (5 = most suspicious) for each of six conventional gray-scale and six new vascular criteria. Thirteen masses proved to be benign and 11 were malignant. 3D provided a stronger subjective appreciation of vascular morphology and allowed somewhat better ultrasound discrimination of malignant masses than did the 2D images or videotapes (specificities of 85%, 79% and 71%, respectively, at a sensitivity of 90%). Only in 3D did the vascularity measures display a trend towards significance in this small study.

The hemodynamics of transjugular intrahepatic portosystemic shunts: investigations with Doppler sonography and development of an in vitro model.

RATIONALE AND OBJECTIVES: We evaluated Doppler sonography-based measurements of transjugular intrahepatic portosystemic shunt (TIPS) function and developed an in vitro model of normal TIPS hemodynamics. METHODS: We reviewed retrospectively the results of all trans-TIPS manometries (N = 116) performed during a 24-month period. Portosystemic pressure gradient was compared with peak stent velocity as measured by angle-corrected Doppler sonography. A flow phantom simulating TIPS was created using 8-, 10-, and 12-mm-diameter wire-mesh stents placed in cylindrical channels with lengths ranging from 3.4 to 6.0 cm. RESULTS: Among 50 trans-TIPS manometries with corresponding Doppler sonography performed on well-functioning shunts, measured portosystemic pressure gradient and peak velocity were not correlated (R2 = .014). On the basis of a regression of measurements in the flow phantom, pressure loss in a stented cylindrical channel was estimated as follows: delta p = rho.(0.145 -0.001.Rey + 0.816.L/D).(Vmean2/2), where rho is the fluid density, Rey is the Reynolds number, L is the channel length, D is the stent diameter, and Vmean is the time-averaged velocity within the stent. Predicted and measured pressure gradients were correlated (R2 = .91). CONCLUSION: Peak velocity in patients with a normally functioning TIPS does not predict the magnitude of the portosystemic pressure gradient.

Endobronchial ultrasound-guided needle aspiration of mediastinal adenopathy.

We conducted a randomized, controlled trial to prospectively confirm that ultrasound-directed transbronchial needle aspiration (USTBNA) results in: (1) improved sensitivity for detecting lymph nodes involved with neoplasm, and (2) a decreased number of aspirates needed to achieve a diagnosis as compared with standard transbronchial needle aspiration (TBNA). The study was conducted in a tertiary medical center on patients undergoing fiberoptic bronchoscopy in the evaluation of enlarged mediastinal lymph nodes. USTBNA or TBNA were followed by rapid, on-site cytopathology examination of the collected specimens. Measurements included the (1) age and sex of the patient, prior diagnosis of cancer, nodal short-axis diameter and node location as determined by computerized tomography (CT), and endobronchial abnormalities at bronchoscopy; (2) number, order, and location of transbronchial aspirates and results of on-site evaluation; (3) results of surgical exploration in patients with negative transbronchial needle aspiration; (4) sensitivity, specificity, and diagnostic accuracy of USTBNA and TBNA; (5) number of aspirates required for successful lymph node aspiration as well as for a diagnosis of cancer for both USTBNA and TBNA; and (6) multiple logistic regression analysis to determine the significance of combinations of clinical predictors and needle aspirate results. Eighty-two bronchoscopic examinations were performed on 80 patients. We found no significant difference between USTBNA and TBNA in sensitivity (82.6% versus 90.5%, respectively), specificity (100% for both), or diagnostic accuracy (86.7% versus 91.7%, respectively). The sensitivity, specificity, and diagnostic accuracy of USTBNA and TBNA were similarly high, regardless of node location (paratracheal or subcarinal). A decrease in the number of aspirates required for lymph node sampling approached statistical significance for all USTBNAs as compared with TBNAs (2.03 +/- 0.19 versus 2.62 +/- 0.25, p = 0.06), but this was not demonstrated for the number required to confirm cancer (1.95 +/- 0.47 versus 2.68 +/- 0.21, p = 0.17). The number of aspirates to successful lymph node aspiration decreased with USTBNA versus TBNA in paratracheal lymph nodes (2.00 +/- 0.20 versus 2.91 +/- 0.34, p = 0.03), but not to a diagnosis of cancer (1.93 +/- 0.25 versus 3.00 +/- 0.58, p = 0.11). No difference was seen in the number of aspirates for subcarinal nodes. The number of TBNA attempts for paratracheal lymph node sampling was inversely correlated with node size (r = 0.48, p = 0.02). No such relation was seen with USTBNA of paratracheal nodes (r = 0.09, p = 0.66), TBNA of subcarinal nodes, or USTBNA of subcarinal nodes. A similar relation was seen between the number of aspirates to a diagnosis of cancer. On multiple logistic regression analysis, a positive transbronchial aspirate was associated only with a larger lymph node and history of prior cancer. We conclude that: (1) in the setting of on-site cytopathology, transbronchial needle aspiration has a high sensitivity, specificity, and diagnostic accuracy in the evaluation of enlarged mediastinal lymph nodes suspected of harboring malignancy; (2) mediastinal anatomy, including vascular structures and lymph nodes, is clearly imaged with endobronchial ultrasonography; (3) a greater short-axis diameter of the mediastinal lymph node and history of a prior malignancy increase the likelihood of a positive transbronchial aspiration; (4) USTBNA exhibits a similarly high diagnostic yield to TBNA in the setting of rapid on-site cytopathology evaluation; (5) USTBNA decreases the number of aspirates required for paratracheal lymph node sampling, which may be particularly useful in sampling smaller paratracheal nodes or at institutions that do not utilize rapid on-site cytopathology evaluation.

Prostate cancer: diagnosis with color Doppler sonography with histologic correlation of each biopsy site.

PURPOSE: To correlate the findings at prostate color Doppler sonography (CDS) with those of site-specific transrectal core biopsy. MATERIALS AND METHODS: Forty-three patients underwent prostate transrectal ultrasonography (US) and biopsy. CDS was performed at all biopsy sites before US-guided core biopsy. Vascularity at CDS was prospectively graded on a scale of 0-2 (0 = no visible peripheral zone [PZ] flow, 2 = markedly increased PZ vascularity). CDS results were correlated with histologic findings from 220 separate biopsy sites that included 27 focal lesions. RESULTS: Of 34 grade 2 biopsy sites, 21 revealed carcinoma, eight revealed prostatitis, and five were negative. CDS depicted at least one focus of carcinoma in seven patients with no gray-scale abnormality. CDS had a sensitivity of 49%, specificity of 93%, and positive predictive value of 62%. CONCLUSION: Focal PZ hypervascularity at CDS is associated with an increased likelihood of prostate cancer or inflammation at biopsy, often without a focal gray-scale abnormality. CDS may help identify an appropriate site for biopsy. A negative CDS scan, however, should not preclude biopsy, as CDS has a limited sensitivity in the detection of all sites of cancer.