Biomedical subjects
Publications and source records attributed to C Palestro.
Radiographic imaging plays an important role in the diagnosis and treatment of paragangliomas. Diagnosis and treatment should be performed as a team effort, with all the involved disciplines working together to provide the best possible individualized work-up and treatment plan for the patient.
The diagnosis of acute pyelonephritis in children remains a clinical challenge. We assessed the feasibility of magnetic resonance imaging (MRI) detection of pyelonephritis in four pediatric patients and compared the results with renal cortical scintigraphy. MRI revealed areas of high signal intensity in the kidney that coincided with photon-deficient regions in the radionuclide scans in two children with acute pyelonephritis. These findings confirm work in experimental animals and indicate that MRI can accurately detect acute pyelonephritis in children.
Localizing active sites of bleeding within the small intestine remains a difficult task. Endoscopic, angiographic or scintigraphic studies may point to the small intestine as the site of blood loss, but at operation, without a palpable lesion, the exact site of bleeding remains elusive. Patients are managed at laparotomy with intraoperative endoscopy, angiography, multiple enterotomies, "blind" resections, or placement of an enterostomy. We describe two patients in whom intraoperative scintigraphy accurately identified active sites of bleeding in the small intestine when other modalities failed. Intraoperative scintigraphy is rapid, easy to perform and is an effective means of identifying active sites of bleeding within the small intestine.
Blood-pool subtraction has been proposed to enhance 111In-labeled platelet imaging of intracardiac thrombi. We tested the accuracy of labeled platelet imaging, with and without blood-pool subtraction, in ten subjects with cardiac thrombi of varying age, eight with endocarditis being treated with antimicrobial therapy and ten normal controls. Imaging was performed early after labeled platelet injection (24 hr or less) and late (48 hr or more). Blood-pool subtraction was carried out. All images were graded subjectively by four experienced, "blinded" readers. Detection accuracy was measured by the sensitivity at three fixed levels of specificity estimated from receiver operator characteristic curve analysis and tested by three-way analysis of variance. Detection accuracy was generally improved on delayed images. Blood-pool subtraction did not improve accuracy. Although blood-pool subtraction increased detection sensitivity, this was offset by decreased specificity. For this population studied, blood-pool subtraction did not improve subjective detection of abnormal platelet deposition by 111In platelet imaging.
Acute radiation nephritis typically affects the kidneys 3-12 months after radiation exposure and may occur with doses as low as 2500 rads. After an initial latent period, the affected portions of the kidneys become swollen and edematous, and develop multiple petechiae. Necrotizing vasculitis and interstitial hemorrhage occur, and the end stage is that of scarring. Two patients are presented in whom localized acute radiation nephritis developed, and whose kidneys demonstrated the characteristic sequential changes of this entity on serial bone imaging.
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Thirty-three cases of anthracycline related cardiotoxicity occurred in our institution in patients with a previously negative cardiovascular history, physical examination, and normal ECG. A total of 95 RNCA studies were performed in this group (73 studies included both rest and exercise RNCA). Twenty-one patients had two or more serial studies. Seventeen had a normal, baseline prechemotherapy study and 16 had studies done following the initiation of therapy. Fourier analysis, consisting of amplitude and phase images, were created for each study. In the subset with a baseline study, the rest LVEF became abnormal first in two of 17 patients (12%), the rest or stress LVEF in ten of 17 (59%), the rest Fourier image analysis in ten of 17 (59%), and the rest or stress Fourier image analysis in 16 of 17 (94%). In the subset without a baseline study, the rest LVEF was abnormal in ten of 16 (63%), the rest or stress LVEF in 15 of 16, (94%), the rest Fourier image analysis in 16 of 16 (100%), and the rest or stress Fourier image analysis in 16 of 16 (100%). The authors conclude that: 1) the exercise RNCA is superior to the rest RNCA alone in the early detection of anthracycline related cardiotoxicity, 2) the single most sensitive indicator of cardiotoxicity is Fourier image analysis; and 3) sequential rest and stress RNCA studies with Fourier amplitude and phase analysis is the most sensitive, noninvasive method of evaluating patients who receive potentially cardiotoxic agents.
Fifty-four patients with a cardiomyopathy were studied by RNCA and Fourier amplitude and phase image analysis. The study group included patients with ischemic cardiomyopathy (27) and an equal number of patients with a primary cardiomyopathy: drug-induced (22), idiopathic (three), radiation-induced (one), and amyloidosis (one). Twenty-eight patients had rest studies alone and 26 had both rest and stress studies (80 total). The mean rest LVEF in the ischemic group was 27.9%, in the drug-induced group 36.5%, and in the idiopathic group 30%. The stress LVEF decreased in 92% of patients with ischemic cardiomyopathy and 45% of patients with primary (drug-induced) cardiomyopathy. Fourier amplitude and phase images were generated for each study. Amplitude and phase images were abnormal in all patients with an ischemic cardiomyopathy. LV amplitude abnormalities were regional and phase was directional. A zone of dysynergy on phase analysis was present in 44% of patients with ischemic cardiomyopathy. In the drug-induced primary cardiomyopathy group, all patients had abnormal amplitude and 86% had abnormal phase. Amplitude abnormalities were global rather than regional and phase patterns were nondirectional. Only one patient had a zone of dysynergy on the phase image. We conclude that the stress LVEF alone cannot consistently differentiate between ischemic and primary cardiomyopathies and that Fourier amplitude and phase analysis may be useful in determining the etiology of a cardiomyopathy (ischemic vs primary).
Forty-one patients (25 male, 16 female) were studied by RNCA in our institution. There were 42 rest studies and 24 stress studies (66 studies total). Sixteen patients were normal, 15 had ASHD, seven had a cardiomyopathy, and three had left-sided valvular regurgitation. Each study was preprocessed using both the standard nine-point smoothing method and Fourier filtering. Amplitude and phase images were also generated. Both preprocessing methods were compared with respect to image quality, border definition, reliability and reproducibility of the LVEF, and cine wall motion interpretation. Image quality and border definition were judged superior by the consensus of two independent observers in 65 of 66 studies (98%) using Fourier filtered data. The LVEF differed between the two processes by greater than .05 in 17 of 66 studies (26%) including five studies in which the LVEF could not be determined using nine-point smoothed data. LV wall motion was normal by both techniques in all control patients by cine analysis. However, cine wall motion analysis using Fourier filtered data demonstrated additional abnormalities in 17 of 25 studies (68%) in the ASHD group, including three uninterpretable studies using nine-point smoothed data. In the cardiomyopathy/valvular heart disease group, ten of 18 studies (56%) had additional wall motion abnormalities using Fourier filtered data (including four uninterpretable studies using nine-point smoothed data). We conclude that Fourier filtering is superior to the nine-point smooth preprocessing method now in general use in terms of image quality, border definition, generation of an LVEF, and cine wall motion analysis. The advent of the array processor makes routine preprocessing by Fourier filtering a feasible technologic advance in the development of the RNCA study.
Fourier amplitude and phase image analysis were evaluated in 66 patients. Thirty patients served as a control group and 36 had coronary artery disease (CAD). Each patient in our control group had a rest and exercise radionuclide cineangiogram (RNCA) study (60 total). The amplitude and phase images for controls were uniform. No statistically significant difference in the histogram distribution of amplitude or phase occurred between rest and exercise. Twenty-five patients with CAD had a prior myocardial infarction (MI). Fourier analysis, when compared to the left ventricular ejection fraction (LVEF) and visual cine wall motion analysis, improved the sensitivity of the rest RNCA study to detect CAD from 68% to 92%. Regional Fourier amplitude and phase image analysis demonstrated an 85% sensitivity in localizing regions of previous infarction. Thirteen of 25 patients with prior MI and an additional 11 patients with recent onset of angina but no previous infarction, had exercise RNCA studies. When compared to cardiac catheterization data, regional Fourier amplitude and phase image analysis demonstrated sensitivities of 87% and 80%, respectively, in correctly identifying clinically significant major coronary artery involvement in these two subsets of patients. Fourier amplitude and phase image analysis were also able to distinguish normals from patients with previous MI, and patients with CAD but no prior infarction. All comparisons were statistically significant. We conclude that the semiquantitative image analysis of Fourier amplitude and phase data increases the clinical utility of the RNCA study in patients with CAD.