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Biomedical subjects

Terri J Vrtiska

Publications and source records attributed to Terri J Vrtiska.

8 recordsLinked to original sources

Renal MR and CT angiography: current concepts.

During the past decade, noninvasive CTA and MRA imaging techniques have replaced catheter angiography for evaluation of the renal arteries. This article reviews techniques for optimizing renal MRA and CTA, assesses the advantages and limitations of MRA and CTA, and provides the current indications for renal vascular imaging including renal artery stenosis screening. New and future developments in these rapidly evolving techniques are also discussed.

Angiography↗

Quantitation of stone burden: imaging advances.

The accurate diagnosis and quantitation of nephrolithiasis in patients with primary hyperoxaluria (PH) often directly impacts the medical and surgical management for individuals with both symptomatic and asymptomatic calculi. Traditionally, depiction of the size, location and appearance of urinary calculi has been provided by kidney, ureter and bladder plain film radiographs with or without tomography. Given advances in imaging technology there is a shift from conventional radiographs to cross-sectional imaging technology, namely unenhanced computed tomography (CT), CT urography, ultrasound and magnetic resonance imaging. These diagnostic techniques provide differing advantages and disadvantages for imaging stone disease. This review outlines imaging advances in the accurate diagnosis and quantitation of patients with metabolically active stone disease such as PH.

Diagnostic Imaging↗

Large cell carcinoma with calcitonin and vasoactive intestinal polypeptide-associated Verner-Morrison syndrome.

Verner-Morrison syndrome, characterized by diarrhea, hypokalemia, and hypochlorhydria, is caused most commonly by vasoactive intestinal polypeptide-secreting islet cell tumors of the pancreas. Verner-Morrison syndrome has not been described as a paraneoplastic syndrome in non-small cell lung cancer. We describe a 38-year-old man with metastatic non-small cell lung cancer of large cell carcinoma with neuroendocrine differentiation who presented with bone metastasis and intractable secretory diarrhea that was unresponsive to pharmacological treatment, including octreotide. Laboratory evaluation indicated elevated serum calcitonin and vasoactive intestinal polypeptide levels. Chemotherapy resulted in a transient response in the patient's diarrhea and neuroendocrine markers. The patient did not respond to further therapy and died 5 months after onset of back pain. To our knowledge, this is the first published case of large cell carcinoma with neuroendocrine differentiation associated with treatment-responsive paraneoplastic Verner-Morrison syndrome.

Adult↗

Three-dimensional CT virtual endoscopy in the detection of simulated tumors in a novel phantom bladder and ureter model.

BACKGROUND AND PURPOSE: Cystoscopy and ureteroscopy have limitations in the evaluation for urothelial tumors, and both are invasive. We studied the utility of three-dimensional (3D) CT virtual endoscopy in phantom models. MATERIALS AND METHODS: A phantom pelvis was constructed of Plexiglas, porcine pelvic bones, and processed animal fat and scanned at various table speeds in a four detector-row CT machine for ability to detect "tumors" of Solidwater plastic polymer. Images were reconstructed at slice thicknesses of 2.5 to 5.0 mm and reconstructed in 3D for evaluation by two radiologists with no knowledge of the scanning parameters or tumor location. Similar studies were performed with a ureter model. RESULTS: With 5-mm slices, the sensitivity for bladder tumors ranged from 67% for 2-mm tumors to 100% for 4-mm tumors, with 12 false-positive findings. The overall sensitivity was 86% with 3.75-mm slices with one false positive, and with 2.5-mm slices, the sensitivity was 93%, again with one false positive. For the ureteral tumors, the overall sensitivities and numbers of false positives were 88.9% and eight with 5.0-mm collimation, 88.9% and four with 3.75-mm collimation, and 100% and three with 2.5-mm collimation. The effective radiation dose for all studies was equivalent to that of a standard abdomen/pelvis scan. CONCLUSIONS: Although virtual endoscopy traditionally has had difficulty detecting tumors <5 mm, the multidetector-row CT protocols used in this study could detect most lesions smaller than this. The scan also depicts the other tissues of the pelvis, which is valuable for staging. The 3D images were produced using data from the CT urogram parameters standard at our institution.

Animals↗

State-of-the-art imaging with 64-channel multidetector CT angiography.

During the past decade, computed tomography angiography (CTA) has become a standard noninvasive imaging method for the depiction of vascular anatomy and pathology. The quality and speed of CTA examinations have increased dramatically as CT technology has evolved from single-channel spiral CT systems (circa 1990) to multichannel (4-, 8-, 10-, and 16-slice) spiral CT systems (circa 1998 through 2001). In 2004, 64-slice multichannel CT technology became available in the United States, with the first installation occurring at the Mayo Clinic College of Medicine. We describe our initial experience using this state-of-the art technology, focusing on examinations that illustrate the increased diagnostic resolution of vascular anatomy and pathology, and the effectiveness of 2-and 3-dimensional postprocessing using a 64-channel CT system. Future applications of 64-channel technology for preoperative and postoperative vascular surgery and endovascular techniques are also described.

Angiography↗

CT urography.

With the recent introduction of multi-detector row helical computed tomography (CT), the radiologic evaluation of patients with urologic disease has changed rapidly. Two major approaches to CT urography have been developed. The first approach combines axial CT with timed excretory urography (EU) performed by using conventional radiography, digital radiography, or CT scanned projection radiography (SPR). This approach produces traditional projection urograms, and the timed imaging technique is familiar to radiologists and clinicians. Additional excretory phase CT can be performed when the EU findings are positive or indeterminate. Improved CT SPR processing technology produces radiographlike images, thus eliminating patient transportation between the CT and urography suites or the necessity for a CT suite with a ceiling-mounted x-ray tube and a modified CT tabletop for performance of EU. The second approach to CT urography combines axial CT with thin-section excretory phase CT. The near-isotropic volume data set enables creation of high-resolution two- and three-dimensional reformatted images. However, the increased amount of radiation and the time required for data manipulation are concerns. Further studies evaluating large numbers of patients with various urothelial abnormalities will be necessary to determine the optimal CT urography technique for clinical practice.

Equipment Design↗