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Biomedical subjects

K J Taylor

Publications and source records attributed to K J Taylor.

At least 37 records · Page 2Linked to original sources

Timing, magnitude, and utility of surgical delay in the TRAM flap: II. Clinical studies.

Transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction was performed in 15 patients 1 week after a preliminary delay procedure. The indications for surgical delay were obesity, smoking, prior radiation therapy, a requirement for large volumes of transmidline tissue, or combinations of these risk factors. The delay procedure consisted of outpatient ligation of the deep and superficial inferior epigastric vessels. Prior to and 1 week following the delay procedure, noninvasive Doppler examinations of the superior epigastric vessels were performed. Following the delay procedure, the diameter of the superior epigastric artery increased from 1.3 +/- 0.2 to 1.8 +/- 0.3 mm (p < 0.001) and the calculated superior epigastric artery flow increased from 7.25 +/- 0.8 to 18.2 +/- 2.7 ml/min (p < 0.001). Breast reconstruction in these high-risk patients was successful without major ischemic complications, but a tendency toward unreliability of zone IV was noted. This clinical observation is consistent with the findings in our animal studies (part I). The preliminary delay procedure was well tolerated with minimal morbidity. We feel that a preliminary delay procedure is a very useful option for breast reconstruction patients at high risk for TRAM flap vascular compromise.

Ambulatory Surgical Procedures↗

Correlation of findings on transvaginal sonography with serum CA 125 levels.

OBJECTIVE: This study was performed to correlate findings on transvaginal sonography with differential levels of serum CA 125. MATERIALS AND METHODS: The study population included 144 patients who underwent transvaginal sonography for suspected pelvic mass and in whom a serum CA 125 level was established as part of the diagnostic workup. Levels of less than 36 U/ml were considered nonelevated; levels equal to or greater than 36 U/ml but less than 50 U/ml were considered mildly elevated; levels of 50-100 U/ml, moderately elevated: and levels greater than 100 U/ml, markedly elevated. Seventy-eight patients had pathologically proven gynecologic disease. Sixty-six patients were followed up with serial sonograms; benign gynecologic disease was diagnosed in 39 of these patients. In the 5-year period included in the study, the patients followed up with serial sonograms were imaged an average of 2.6 times during 2.1 years. RESULTS: Transvaginal sonography had a sensitivity of 97%, a specificity of 97%, and an overall accuracy of 94% for correctly revealing pathologically proven gynecologic disease. Interpreters of the sonograms misdiagnosed no carcinomas, even in patients with nonelevated levels of CA 125. Likewise, no benign lesions were incorrectly interpreted as malignant, even in patients with markedly elevated levels of CA 125. When interpreters used CA 125 alone to evaluate for malignancy, those interpreters achieved a sensitivity of 85% and a specificity of 29% in all patients with levels of CA 125 greater than or equal to 36 U/ml. Also, the use of CA 125 alone to evaluate for malignancy had an even lower specificity (17%) in postmenopausal patients who had levels of CA 125 that exceeded 100 U/ml. CONCLUSION: Transvaginal sonography is a sensitive tool for diagnosing gynecologic disease in spite of misleadingly high or low levels of CA 125. Evaluation of levels of CA 125 should be discouraged before sonograms are obtained.

Biomarkers, Tumor↗

Transrectal sonography in staging rectal carcinoma: the role of gray-scale, color-flow, and Doppler imaging analysis.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of combining gray-scale sonography with color-flow imaging and pulsed Doppler transrectal sonography in the staging of rectal carcinoma. SUBJECTS AND METHODS: Thirty-nine patients with primary rectal carcinoma underwent transrectal sonography. The rectal masses were staged T1-T2 or T3-T4 on the basis of gray-scale imaging. The local nodes were classified as benign or malignant on the basis of size and echogenicity. In 22 patients, color-flow imaging and pulsed Doppler imaging of the rectal mass and of the local lymph nodes were performed. The peak systolic velocity (PSV) and end diastolic velocity were documented, and the resistive index was calculated. RESULTS: Gray-scale imaging alone was used to stage T1-T2 masses with 88% sensitivity and 82% specificity. T3-T4 masses were staged with 82% sensitivity and 88% specificity. Overall accuracy was 85%. Gray-scale imaging of lymph nodes using a discriminatory size of less than or equal to 5 mm for benign nodes and greater than 5 mm for malignant nodes yielded a sensitivity of 100%, a specificity of 28%, and an accuracy of 52%. Using receiver operating characteristic curve analysis, we determined that a size of greater than or equal to 7 mm was optimal for characterizing nodes. Such a size provided an accuracy of 83%. PSV of less than 25 cm/sec distinguished T3-T4 from T1-T2 rectal masses with 75% sensitivity, 80% specificity, and 77% accuracy. A PSV of greater than 20 cm/sec classified a node as malignant with 100% sensitivity, 62% specificity, and 76% accuracy. A resistive index of greater than 0.61 classified a node as malignant with 71% sensitivity, 85% specificity, and 80% accuracy. CONCLUSION: Color-flow imaging and pulsed Doppler imaging are useful additions to gray-scale transrectal sonography in staging primary rectal carcinomas. The combination has most value when evaluating perirectal nodes.

Carcinoma↗

Evaluation of Doppler ultrasonography as a means of monitoring in vitro fertilization and embryo transfer cycles: preliminary results and findings.

In vitro fertilization imposes an emotional and financial burden on infertile couples and has a relatively low success rate, but it offers their only means of conception. As uteroovarian perfusion varies during the menstrual cycle and may be related to uterine receptivity, we sought to identify hemodynamic parameters that would be of use in monitoring stimulated cycles and in making decisions about the timing of in vitro fertilization. Uteroovarian perfusion patterns in patients undergoing ovulation induction and embryo transfer were compared with normally cycling volunteers. Significant changes in ovarian perfusion were seen with suppression and stimulation. Despite manipulation, no difference in uterine perfusion was seen between the groups in the late luteal phase, the crucial time of implantation. We conclude that Doppler ultrasonography may be useful in monitoring artificial cycles and in predicting uterine receptivity.

Adult↗

Contrast enhanced sonography of visceral perfusion defects in dogs.

The purpose of this study was to assess the utility of an intravenous contrast agent (FS069) for visualization of normal visceral perfusion compared with perfusion after segmental infarction in a canine model. Six mongrel dogs were used as subjects. Splenic, renal, hepatic, and small bowel perfusion was assessed without and with intravenous microbubble contrast material using gray scale, color Doppler, pulsed Doppler, and color power Doppler sonography. Each organ was then reassessed after ligation of a segmental vessel. Imaging was again performed without and with contrast material using all four ultrasonographic modalities. In all organs color and spectral Doppler signals were significantly enhanced from normally perfused tissue after intravenous contrast agent injection. Ischemic areas were more conspicuous after contrast medium injection except in the liver. Hepatic perfusion was maintained by portal flow in the liver despite arterial ligation. Ligation of collateral arcades was required to produce bowel ischemia. Intravenous injection of FS069 improves evaluation of visceral perfusion and identification of focal visceral ischemia in dogs. These results suggest that this agent may increase sensitivity for detection of blood flow in small and deep vessels.

Albumins↗

Contrast-enhanced ultrasonographic visualization of gonadal torsion.

The purpose of this study was to investigate the effect of use of intravenous ultrasonographic contrast agent in the diagnosis of gonadal torsion in an animal model. After examination of perfusion of normal gonads in male and female dogs, torsion was produced and maintained mechanically. Presence and pattern of blood flow was then reassessed before and after administration of varying doses of perfluorocarbon-filled microsphere intravenous contrast agent. Modes of examination included gray scale, color flow, color power, and spectral analysis using a transducer placed directly on the surgically exposed gonads. Although no enhancement was perceptible on gray scale images, color and spectral Doppler signals were significantly stronger after injection of contrast agent in both normal and rotated gonads. Perfusion asymmetry was more obvious. Some residual flow was seen in partially rotated testes, and absence of flow was documented in both partially and fully rotated ovaries. Use of intravenous contrast medium improves demonstration of altered flow patterns in ischemic gonads, allowing more confident diagnosis.

Animals↗

Definition and refinement of a region of loss of heterozygosity at 11q23.3-q24.3 in epithelial ovarian cancer associated with poor prognosis.

Previous cytogenetic and loss of heterozygosity (LOH) data suggest that disruption of chromosome 11q23-qter occurs frequently in epithelial ovarian cancer and is associated with an adverse clinicopathological phenotype. Ten polymorphic microsatellite repeat loci were analyzed by PCR from the 11q22-q25 region between D11S35 and D11S968 in 40 ovarian tumors (including 31 epithelial ovarian cancers). Two distinct regions of loss were detected, suggesting possible sites for genes involved in epithelial ovarian neoplasia: a large centromeric region between D11S35 and D11S933 (11q22-q23.3) and a telomeric 8.5-Mb region lying between D11S934 and D11S1320 (11q23.3-24.3) not previously defined. LOH of the latter region but not the former one was significantly associated with poor survival, despite all tumors in this study having LOH somewhere on chromosome 11. This analysis provides a starting point for positional cloning.

Carcinoma↗

Volumetric flow estimation in vivo and in vitro using pulsed-Doppler ultrasound.

The measurement of volumetric blood flow in small vessels in vitro and in vivo poses a significant technological challenge. In this study, two pulsatile flow models were developed, one with a 3.2-mm lumen diameter and one with a 12.7-mm lumen diameter, to assess the accuracy of volumetric flow estimation of two pulsed-Doppler devices, a Crystal Biotech VF1 20-MHz system with either a cuff-mounted or a needle-mounted probe and an Advanced Technology Laboratories Ultramark 9 High Definition Imaging system with a 5-MHz linear array transducer. The VF1 volumetric flow error was measured in the 3.2-mm phantom over a variety of pulsatile and continuous waveforms. The accuracy of the VF1 was also tested in porcine femoral and renal arteries. VF1 volumetric flow error ranged from 4.8% to 54.3% in the in vivo studies. The ATL demonstrated similar volumetric flow errors in the porcine femoral artery (approximately 3.2 mm diameter), but these errors were reduced to < or = 17.4% in the 12.7-mm-diameter in vitro flow model.

Animals↗

Direct evidence of cavitation in vivo from diagnostic ultrasound.

Recent increases in the pressure output of diagnostic ultrasound scanners have led to an interest in establishing thresholds for bioeffects in many organs including the lungs of mammals. Damage may be mediated by inertial cavitation, yet there have been no such direct observations in vivo. To explore the hypothesis of cavitation-based bioeffects from diagnostic ultrasound, research has been performed on the thresholds of damage in rat lungs exposed to 4.0-MHz pulsed Doppler and color Doppler ultrasound. A 30-MHz active cavitation detection scheme complementing these studies provides the first direct evidence of cavitation in vivo from diagnostic ultrasound pulses.

Animals↗

Cardiac perforation associated with continuous infusional chemotherapy.

The case history is reported of a 51-year-old man with metastatic colonic carcinoma who was receiving a continuous 5-fluorouracil infusion via a central venous catheter and who developed cardiac perforation and pericardial effusion. This complication has not previously been reported in association with continuous chemotherapy infusion.

Antineoplastic Agents↗

Changes in stroke distance in response to haemorrhage in a swine model.

OBJECTIVE: To determine, using an animal model of blood loss, (1) if stroke distance, derived non-invasively from the time integral of the maximum velocity of red cells in the aorta, changed to a greater extent than heart rate and mean arterial pressure (MAP), which are recognised to be unreliable indicators of blood loss; (2) if changes in stroke distance reflected changes in stroke volume derived from thermodilution cardiac output measurements. METHODS: Eight anaesthetised swine had baseline measurements of heart rate, MAP, stroke volume, and stroke distance and were then exsanguinated at a rate of 1 ml/kg/min. Percentage changes from baseline of heart rate, MAP, stroke volume, and stroke distance were compared after 10, 20, and 30 ml/kg blood loss. The animal's blood was then reinfused at the rate of 2 ml/kg/min for 15 min, followed by normal saline 1 ml/kg/min. Percentage changes from baseline measurement of stroke volume and stroke distance over the whole experiment were evaluated by regression analysis. RESULTS: Heart rate, MAP, and stroke distance changed +7.9%, -22.5%, and -18.1% respectively (from baseline values) after 10 ml/kg blood loss; +23.2%, -44.0%, and -47.4% after 20 ml/kg blood loss; and +55.7%, -62.0%, and -69.8% after 30 ml/kg blood loss. Regression analysis of percentage changes in stroke volume and stroke distance from their baseline values at experimental time zero is stroke volume = 1.014 x stroke distance -2.156, r = 0.92, n = 54, P < 0.0001. CONCLUSIONS: (1) At maximal blood loss, stroke distance changes to a greater extent than heart rate and MAP. (2) Changes in stroke distance reflected changes in stroke volume but with less variability at lower values. Stroke distance may be a more useful measure of blood loss than heart rate and MAP.

Animals↗

Doppler color flow imaging surveillance of deep vein thrombosis in high-risk trauma patients.

To determine the prevalence of upper and lower extremity deep vein thrombosis in high-risk trauma patients, 136 consecutive high-risk trauma patients were prospectively evaluated with weekly Doppler color flow imaging. Incomplete compressibility and visualized intraluminal thrombus were considered diagnostic of deep vein thrombosis. Pulmonary embolus was documented by pulmonary arteriography. Deep vein thrombosis occurred at 27 non-contiguous sites in 19 patients (14%). Eight of 27 cases of deep vein thrombosis (30%) involved the upper extremity and 19 (70%) occurred in the lower extremity. Twenty-one of 27 deep vein thromboses (78%) were partially occlusive, whereas six (22%) were occlusive. Pulmonary embolus was documented in three patients (2.2%). Doppler color flow imaging detected occult deep vein thrombosis in 14% of high-risk trauma patients (30% occurring in the upper extremity).

Adolescent↗

Early detection and screening for ovarian cancer.

Ovarian cancer is associated with postmenopausal women of North American or European descent, nulliparous women, and women with a first-degree relative with an epithelial ovarian cancer. Methods for early detection of ovarian cancer are the pelvic examination, ultrasound techniques, and CA-125 monitoring, none of which are highly sensitive or specific for the disease. At the Yale-New Haven Medical Center, first-degree relatives of women with epithelial ovarian cancer were invited to participate in an intense ovarian cancer screening program consisting of tumor markers, endovaginal ultrasound and color Doppler flow studies, and physical examinations performed in a serial fashion. The false-positive rate for the tumor markers varied from 2 to 9% at initial evaluation of the first 247 participants. Endovaginal ultrasound and color Doppler flow techniques were used to evaluate 326 ovaries in 169 women. Resistive indices < 0.5 were present in 26 ovaries (8.4%), and peak systolic velocities > 30 cm/sec occurred in 7 ovaries (2.3%). To date, four breast cancers have been detected, three cervical intraepithelial neoplasias have been identified, and three atypical adenomatous hyperplasias were diagnosed. No epithelial ovarian cancer was found. Isolated screening for ovarian cancer even in high-risk women is not cost effective. Women screened for ovarian cancer should also be evaluated for cancers of the breast, cervix, colon, rectum and endometrium. Isolated abnormal screening test values are not an indication for surgery.

Biomarkers, Tumor↗

The use of ultrasound in the non-invasive detection of changes in the renal circulation in response to blood loss using an animal model.

Using a continuous haemorrhage model, 8 anaesthetised swine were bled 1 ml/kg per min for 30 min. The resistance index (RI) of the main renal artery, interlobar and arcuate vessels all significantly increased. Cortical Doppler signals were lost in 4 animals at a mean arterial pressure of 26 mmHg. After reinfusion of blood and normal saline only the RI of the interlobar vessels was significantly different from baseline readings. Ultrasound demonstrated non-invasively changes in regional blood flow within the kidney in response to hypovolaemic shock.

Animals↗

Common pitfalls of endovaginal color Doppler flow imaging.

Endovaginal color Doppler flow imaging is a relatively new technique that combines gray-scale sonography with duplex Doppler and color Doppler flow techniques. However, such imaging is associated with multiple pitfalls. Technical errors are caused by improper setting of the color flow parameters. The color velocity scale, color priority, color gain, color sensitivity, and color wall filter should be adjusted to optimize color flow information. Technical errors may result in false diagnosis of ovarian torsion, malignancy, and ectopic pregnancy. Errors in interpretation result from an inability to identify and correctly characterize tissue vascularity. Such errors include failure to distinguish placental from luteal flow and failure to characterize adnexal masses accurately. In addition, functional ovarian cysts may demonstrate increased vascularity throughout the menstrual cycle and simulate cancer. Recognition of the common pitfalls of endovaginal color Doppler flow imaging and integration of clinical and sonographic features will reduce misinterpretation and improve diagnostic accuracy.

Artifacts↗

Quantitative Doppler assessment of acute scrotal inflammation.

PURPOSE: To establish quantitative Doppler criteria for acute unilateral epididymitis and/or orchitis. MATERIALS AND METHODS: Triplex ultrasonography (US) was used to prospectively evaluate 31 patients with acute hemiscrotal pain and 15 asymptomatic control subjects. Morphology and perfusion were assessed, and peak systolic velocities (PSVs) were recorded. Ratios of PSV were calculated by using values from the right and left sides. RESULTS: PSVs in control subjects differed significantly from those in patients (P < .0001). A PSV > or = 15 cm/sec produced diagnostic accuracy of 90% for orchitis and 93% for epididymitis: Five of six false-negative findings were in patients younger than age 15 years. Epididymal PSV ratios > or = 1.7 or testicular ratios > or = 1.9 were diagnostic of acute inflammation (P < .0001). In three cases, morphologic and color Doppler findings were normal and only the PSV ratios were diagnostic. CONCLUSION: PSV and PSV ratios provide diagnostic criteria for acute unilateral epididymitis and/or orchitis that are more accurate than morphologic evaluation and color flow imaging either alone or in combination.

Acute Disease↗

Characterization of focal hepatic lesions with duplex sonography: findings in 198 patients.

OBJECTIVE: The purpose of this study was to determine the value of duplex Doppler sonography in the characterization of focal hepatic lesions. SUBJECTS AND METHODS: Duplex Doppler sonography with a 3-MHz transducer was performed prospectively on 198 patients with focal hepatic lesions. One hundred thirty-two patients had pathologically proved diagnoses, confirming 46 hepatomas and 86 metastatic lesions. Twenty-three hemangiomas were confirmed either with tissue, tagged RBC study, MR imaging, or hemangioma CT protocol. Forty-three patients with no history of cancer had benign lesions that were established on the basis of follow-up imaging and at least a 2-year clinical history with no evidence of cancer. RESULTS: Thirty-two hepatomas and four metastatic lesions had Doppler shifts of 4.5 kHz or more, giving a 70% sensitivity, 95% specificity, and 89% positive predictive value in distinguishing hepatomas from metastatic lesions. Forty-three hepatomas, 47 metastatic lesions, one hemangioma, and three benign lesions had Doppler shifts of 1.75 kHz or more, giving a 68% sensitivity, 94% specificity, and 96% positive predictive value in distinguishing malignant from benign lesions. Doppler shifts (mean +/- SD) were as follows: hepatomas, 4.72 +/- 1.72 kHz; metastases, 1.99 +/- 1.63 kHz; and hemangiomas, 0.53 +/- 0.75 kHz. These differences in mean Doppler shifts were statistically significant (p < .0001). CONCLUSION: Duplex Doppler sonography aids in distinguishing hepatomas from metastases and malignant from benign hepatic lesions with a high degree of specificity but low sensitivity.

Adult↗