Search PubMed⌕ Search

Biomedical subjects

Robert P Hartman

Publications and source records attributed to Robert P Hartman.

9 recordsLinked to original sources
PubMed2006

Prostate cancer: comparison of local staging accuracy of pelvic phased-array coil alone versus integrated endorectal-pelvic phased-array coils. Local staging accuracy of prostate cancer using endorectal coil MR imaging.

To compare the visibility of anatomical details and prostate cancer local staging performance of pelvic phased-array coil and integrated endorectal-pelvic phased-array coil MR imaging, with histologic analysis serving as the reference standard. MR imaging was performed in 81 consecutive patients with biopsy-proved prostate cancer, prior to radical prostatectomy, on a 1.5T scanner. T2-weighted fast spin echo images of the prostate were obtained using phased-array coil and endorectal-pelvic phased-array coils. Prospectively, one radiologist, retrospectively, two radiologists and two less experienced radiologists working in consensus, evaluated and scored all endorectal-pelvic phased-array imaging, with regard to visibility of anatomical details and local staging. Receiver operator characteristics (ROC) analysis was performed. Anatomical details of the overall prostate were significantly better evaluated using the endorectal-pelvic phased-array coil setup (P<0.05). The overall local staging accuracy, sensitivity and specificity for the pelvic phased-array coil was 59% (48/81), 56% (20/36) and 62% (28/45), and for the endorectal-pelvic phased-array coils 83% (67/81), 64% (23/36) and 98% (44/45) respectively, for the prospective reader. Accuracy and specificity were significantly better with endorectal-pelvic phased-array coils (P<0.05). The overall staging accuracy, sensitivity and specificity for the retrospective readers were 78-79% (P<0.05), 56-58% and 96%, for the endorectal-pelvic phased-array coils. Area under the ROC curve (Az) was significantly higher for endorectal-pelvic phased-array coils (Az=0.74) compared to pelvic phased-array coil (Az=0.57), for the prospective reader. The use of endorectal-pelvic phased array coils resulted in significant improvement of anatomic details, extracapsular extension accuracy and specificity. Overstaging is reduced significantly with equal sensitivity when an endorectal-pelvic phased-array coil is used.

Adult↗
PubMed2006

Hysterosalpingography for assessing efficacy of Essure microinsert permanent birth control device.

OBJECTIVE: The Essure microinsert is a new U.S. Food and Drug Administration-approved method of birth control. The objective of this study is to report our initial experience using hysterosalpingography (HSG) to assess its efficacy for permanent tubal occlusion. CONCLUSION: The Essure microinsert produced tubal blockage in all patients. As this device may become more widely used, radiologists should be aware of the device's appearance and be able to assess device position and presence of tubal occlusion on HSG.

Adult↗
PubMed2005

Prostate MR imaging at high-field strength: evolution or revolution?

As 3 T MR scanners become more available, body imaging at high field strength is becoming the subject of intensive research. However, little has been published on prostate imaging at 3 T. Will high-field imaging dramatically increase our ability to depict and stage prostate cancer? This paper will address this question by reviewing the advantages and drawbacks of body imaging at 3 T and the current limitations of prostate imaging at 1.5 T, and by detailing the preliminary results of prostate 3 T MRI. Even if slight adjustments of imaging protocols are necessary for taking into account the changes in T1 and T2 relaxation times at 3 T, tissue contrast in T2-weighted (T2w) imaging seems similar at 1.5 T and 3 T. Therefore, significant improvement in cancer depiction in T2w imaging is not expected. However, increased spatial resolution due to increased signal-to-noise ratio (SNR) may improve the detection of minimal capsular invasion. Higher field strength should provide increased spectral and spatial resolution for spectroscopic imaging, but new pulse sequences will have to be designed for overcoming field inhomogeneities and citrate J-modulation issues. Finally, dynamic contrast-enhanced MRI is the method of imaging that is the most likely to benefit from the increased SNR, with a significantly better trade-off between temporal and spatial resolution.

Artifacts↗
PubMed2005

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↗
PubMed2004

Applications of positron emission tomography imaging, intraoperative ultrasonography, magnetic resonance imaging, and angiography in the evaluation of renal masses.

Most renal masses and cysts are adequately characterized by ultrasonography or computerized tomography. Occasionally, further diagnostic evaluation is needed. Magnetic resonance imaging has emerged as the premier study to evaluate suspected tumor thrombus and to plan the operative technique in challenging cases. Intraoperative ultrasonography is a valuable real-time imaging modality for delineating tumor extent and margins during nephron-sparing surgery and in evaluating the presence of synchronous multifocality. Additionally, localized central renal tumors can be treated with ultrasonography-guided radiofrequency ablation. Positron emission tomography has little use in the diagnostic evaluation of renal masses, but may be useful in staging equivocal cases and in evaluating suspected recurrence or metastases in patients after nephrectomy for renal cell carcinoma.

Humans↗
PubMed2004

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↗
PubMed2004

Effect of granulocyte-stimulating factors on marrow of adult patients with musculoskeletal malignancies: incidence and MRI findings.

OBJECTIVE: Our goal was to determine the incidence and pattern of red marrow reconversion on MRI of adults receiving granulocyte-stimulating factors as part of their chemotherapy regimen for primary musculoskeletal neoplasms and correlate the changes with WBC counts. MATERIALS AND METHODS: Twenty-five adults with soft-tissue sarcomas (n = 15) or primary bone tumors (n = 10) who underwent chemotherapy that included granulocyte-stimulating factors formed the study group. Two radiologists retrospectively evaluated the MRI studies by consensus before and after therapy to determine the presence of changes consistent with red marrow reconversion. Changes were categorized by appearance on T1- and T2-weighted images for location, pattern, and extent of marrow involvement. WBC counts at the time of MRI were recorded. Records were examined for evidence of marrow-infiltrating tumors or metastases. RESULTS: Ten (40%) of the 25 patients underwent bone marrow changes consistent with red marrow reconversion. In seven (70%) of 10 patients, the changes were diffuse in visualized bones and simulated diffuse marrow-infiltrative tumor. In three (30%) of 10 patients, the changes were focal, simulating metastases. T2 signal prolongation was identified in the marrow reconversion in nine patients (90%), although all had shortened T1 signal. Four patients (40%) had elevated WBC counts at the time of the MRI after therapy, but all had shortened T1 signal. Four patients (40%) had elevated WBC counts at the time of the MRI after therapy, five (50%) had normal counts, and one (10%) had a below-normal count. No osseous metastases or marrow-infiltrating tumors were found during follow-up. CONCLUSION: Forty percent of patients showed marrow changes mimicking tumor on MRI that were attributable to red marrow reconversion, which correlated moderately with WBC response.

Adult↗
PubMed2003

Evaluation of renal causes of hypertension.

There are many renal causes of hypertension. Although RAS is the most common, other renal lesions can result in hypertension. Any evaluation of the kidney for hypertension should take all of these potential renal etiologies into consideration.

Diagnostic Imaging↗