Myron A. Pozniak

University of Wisconsin–Madison

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Fred T. Lee

University of Wisconsin–Madison

Timothy P. Szczykutowicz

University of Wisconsin–Madison

Frank N. Ranallo

University of Wisconsin–Madison

Paul L. Allan

Edinburgh Royal Infirmary

Paul A. Dubbins

Plymouth Hospital

Stephen Y. Nakada

University of Wisconsin–Madison

Girma Tefera

University of Wisconsin–Madison

K A Scanlan

Radiology Associates

Anthony M. D’Alessandro

University of Wisconsin–Madison

Frederick Kelcz

University of Wisconsin–Madison

Cooperative Institutions

University of Wisconsin–Madison

108

UW Health University Hospital

Highland Community College - Illinois

Madison Group (United States)

William S. Middleton Memorial Veterans Hospital

University of Michigan–Ann Arbor

Thomas Jefferson University

Baylor College of Medicine

University of Wisconsin System

National Institutes of Health

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Intraoperative Sonography of Intracranial Arteriovenous Malformations

Journal of Ultrasound in Medicine (2004)

Sara A. Griffith Myron A. Pozniak Carol Mitchell Michael E. Ledwidge Robert F. Dempsey

Objective. We have advanced the application of intraoperative neurosonography by combining gray scale sonographic imaging with pulsed wave Doppler and color flow Doppler imaging to guide and confirm resection of arteriovenous malformations of the brain. We want to share our technique with the imaging community. Methods. We present a review of our scan technique as it has evolved over the 3 years during which we have been assisting our neurosurgical team. Results and Conclusions . Our experience has indicated that a combination of sonographic imaging and color and spectral Doppler imaging improves surgical resection of such lesions.

Color doppler

Arteriovenous malformation

Surgical resection

Doppler sonography

10.7863/jum.2004.23.8.1065

Cite

Citations (14)

Sonography of Testicular Tumors and Tumor-Like Conditions: A Radiologic-Pathologic Correlation

Critical Reviews in Diagnostic Imaging (1998)

Michael J. Geraghty Fred T. Lee Stephen A. Bernsten Kennedy W. Gilchrist Myron A. Pozniak

Malignant testicular tumors are an important clinical problem, and ultrasound is the most frequently ordered imaging modality once a palpable scrotal mass is discovered. Numerous articles discussing the role of ultrasound in the evaluation of testicular pathology have confirmed the value of preoperative imaging. This article presents a review of imaging literature regarding testicular neoplasms, with an emphasis on correlation of gross and microscopic tumor pathology and imaging findings. Also included are sections on anatomy, epidemiology, histogenesis, and tumor markers.

Testicular tumor

Histogenesis

Gross examination

10.3109/10408379891244163

Cite

Citations (36)

Spectral and color Doppler artifacts.

Radiographics (1992)

Myron A. Pozniak James A. Zagzebski K A Scanlan

Artifacts in spectral and color Doppler imaging can be confusing and lead to misinterpretation of flow information. The authors review these artifacts by considering three main causes: inappropriate equipment settings, anatomic factors, and physical and technical limitations of the modality. Incorrect gain, wall-filter, or velocity scale settings can cause loss of clinically important information or distortion of the tracing. Reflection of the Doppler signal from highly reflective surfaces can create a color Doppler mirror image. Vascular motion can introduce artifactual variation in velocity as the sample volume passes through different velocities in a laminar flow state. Unintentional motion can cause a generalized Doppler shift. Increasing the angle of Doppler interrogation degrades the quality of the tracing and gives the impression of spectral broadening. As angulation approaches 90 degrees, directional ambiguity can occur, suggesting bidirectional flow. Grating and side lobes can interrogate areas unrelated to the sample volume and introduce extraneous Doppler information to the apparent area of interrogation. Recognition of these artifacts is essential to proper interpretation of Doppler information and rendering a correct diagnosis.

Tracing

10.1148/radiographics.12.1.1734480

Cite

Citations (87)

PS28. Clinical Utility and Safety of Noncontrast Computed Tomography for Follow-Up After Endovascular Abdominal Aortic Aneurysm Repair

Journal of Vascular Surgery (2010)

Joseph L. Bobadilla Pasithorn A. Suwanabol Scott B. Reeder Myron A. Pozniak Girma Tefera

Endovascular aneurysm repair

Computed Tomography Angiography

10.1016/j.jvs.2010.02.093

Cite

Citations (0)

List of contributors

Elsevier eBooks (2006)

Paul L. Allan Jonathan D. Berry Paul A. Dubbins Karen S. Gallagher Peter R. Hoskins

10.1016/b978-0-443-10116-8.50004-x

Cite

Citations (0)

Ecografía Doppler del escroto

Elsevier eBooks (2008)

Myron A. Pozniak

10.1016/b978-84-8086-328-5.50012-5

Cite

Citations (0)

Ultrasound Evaluation of the Transplanted Liver, Kidney and Pancreas

CRC Press eBooks (2008)

Myron A. Pozniak Mitchell Tublin

The caudate lobe of the liver is anatomically distinct from both the right and the left hepatic lobes. It is interposed among the inferior vena cava posteriorly, the left hepatic lobe anteriorly and superiorly, and the main portal vein inferiorly (Fig. 8) (3). The proximal horizontal portion of the left portal vein (i.e., pars transversal) courses over the anterior margin of the inferior caudate lobe, separating it from the more anteriorly positioned medial segment of the left hepatic lobe (Fig. 6B). The left anterior margin of the caudate lobe is separated from thelateral segment of the left hepatic lobe by the fissure for the ligamentum venosum (Fig. 8). On the transverse view, the caudate lobe, between the inferior vena cava and the bifurcation of the portal vein, is contiguous with the right lobe. The right inferior margin of the caudate lobe extends in a tongue-like projection, known as the caudate process, between the inferior vena cava and the adjacent main portal vein and the medial portion of the right hepatic lobe. In most persons, the caudate process is small, permitting contact between the main portal vein and the inferior vena cava, and, thus, is not recognized sonographically. The papillary process is a small, ovoid prominence on the anteroinferior aspect of the caudate lobe. Both left and right portal triads give off portal-venous and hepatic-arterial branches to the caudate lobe and receive from it bile duct tributaries. The initial horizontalMain lobar Separates right lobe from left lobe Cephalic portion: middle hepatic vein Caudal portion: gallbladder fossa Right intersegmental Separates anterior and posterior segments of right lobe Right hepatic vein Left intersegmental Separates medial and lateral segments of left lobe Cranial third: left hepatic vein Middle third: ascending portion of left portal vein Caudal third: ligamentum teres Falciform ligament Ligamentum teres Separates medial and lateral segments of left lobe Ligamentum teres Falciform ligament Ligamentum venosum Separates caudate lobe from lateral segment of left lobeTABLE 2 ■ Fissures of the LiverFissure Usefulness Structures within the Fissureportion of the left portal vein gives off several branches to the caudate lobe (Fig. 6B). The caudate lobe is drained by a series of small, short, venous channels that extend directly from the posterior aspect of the caudate lobe into the inferior vena cava adjacent to the posterior margin of the caudate lobe. Three major anatomic landmarks-the fissure for the ligamentum venosum, the inferior vena cava, and the pars transversa of the left portal vein-permit sonographic localization of the caudate lobe (3).

10.3109/9781420004632-16

Cite

Citations (0)

Radiographic and CT findings of blunt chest trauma: aortic injuries and looking beyond them.

Radiographics (1998)

Janet E. Kuhlman Myron A. Pozniak Jenna Collins Barbara L. Knisely

Increasingly, helical CT is being used to screen trauma patients for aortic injury. Most aortic injuries visible at CT occur at or near the level of the ligamentum arteriosus; these injuries manifest as mediastinal hematoma, aortic contour deformity, intimal flaps, intraluminal debris, pseudoaneurysm, and pseudocoarctation. In the process of searching for aortic injury, however, the radiologist should not overlook other serious and more common thoracic injuries. Tracheobronchial tears appear at CT and radiography with persistent pneumothorax, subcutaneous emphysema, "fallen lung" sign, and malposition of endotracheal tube. The ruptured diaphragm, which tears more often on the left, appears asymmetric, irregular, or discontinuous, with herniation of bowel or viscera into the chest. In esophageal rupture, CT and radiography demonstrate left pneumothorax, pneumomediastinum, subcutaneous emphysema, and pleural effusion and atelectasis on the left. CT is better than trauma radiography for depicting fractures of the thoracic vertebral bodies and ribs, as well as for revealing pulmonary contusions and lacerations. CT is also useful for demonstrating unsuspected injuries caused by seat belts. Observation of these injuries should prompt a search for other serious internal organ injuries.

Pneumomediastinum

Atelectasis

Hemothorax

Aortic rupture

Pseudoaneurysm

10.1148/radiographics.18.5.9747609

Cite

Citations (81)

Upper inferior vena caval anastomotic stenosis in liver transplant recipients: Doppler US diagnosis.

Radiology (1993)

Armando Rossi Myron A. Pozniak N P Zarvan

Ultrasound (US) is routinely used as a screening tool for liver transplant dysfunction. Its use in the detection of significant vascular complications of liver transplantation such as thrombosis or stenosis of the hepatic artery and portal vein is well recognized. Its role in the detection of anastomotic stenosis of the inferior vena cava (IVC) has not been defined. The authors present US findings in five patients with such stenosis. The gray-scale and Doppler findings in all cases consisted of loss of normal hepatic vein and IVC periodicity. Some studies also showed distention of the hepatic veins and IVC and a high-velocity jet at the anastomosis, and in one case the stenosis was visualized with color Doppler US. While there are other causes of absent periodicity in the hepatic veins, this finding in the appropriate clinical setting may be a sensitive indicator of upper IVC anastomotic stenosis.

Doppler ultrasound

10.1148/radiology.187.2.8475278

Cite

Citations (44)

Intraoperative Doppler to Measure Cerebrovascular Resistance as a Guide to Complete Resection of Arteriovenous Malformations

Neurosurgery (2004)

Robert J. Dempsey Roham Moftakhar Myron A. Pozniak

OBJECTIVE: Intraoperative color Doppler ultrasound has been used to locate arteriovenous malformations (AVMs). We describe the use of spectral Doppler to measure flow resistance and resistive index (RI) of vessels around the nidus to distinguish feeding arteries from en passant and normal vessels. This is particularly helpful in small AVMs and aids in the identification of normal vessels and completeness of resection by ruling out persistent low RI flow. METHODS: Seven patients with AVMs underwent resection. Spectral Doppler applied to the vessels in proximity to the AVM, along with calculated RI, was used to identify feeding arteries and draining veins. After presumed surgical resection of the AVM, pre-resection and postresection RIs were compared to identify residual AVM. Postoperative angiography was performed in all seven patients to confirm complete resection of the AVM. RESULTS: The mean pre-resection RI of vessels feeding the AVM was 0.34 (±0.01). In five patients without residual nidus on the basis of postresection color Doppler and postoperative angiogram, the postresection RI was 0.62 (±0.04). In two patients, the postresection scan identified a nidus with persistent low RI flow. Once residual AVM was resected, the RI became significantly higher. A postoperative angiogram confirmed complete resection of the AVM in all patients. CONCLUSION: Intraoperative duplex Doppler allowed more accurate localization of the AVM nidus. RI of the vessels around the AVM helped to distinguish vessels feeding the AVM from en passant vessels. Furthermore, comparison of pre-resection and postresection RI accurately indicated the completeness of resection.

Arteriovenous malformation

10.1227/01.neu.0000126879.95006.46

Cite

Citations (22)