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Biomedical subjects

E L Kramer

Publications and source records attributed to E L Kramer.

At least 19 recordsLinked to original sources

Radionuclide quantitation of renal function.

Quantitation of renal function may be performed with a variety of radiopharmaceuticals which reflect slightly different renal functions. Plasma sampling techniques and imaging techniques have been used to derive absolute measurements of renal function. The addition of imaging permits the determination of relative or "split" function. Time-activity curves from renal studies provide other quantitative parameters of function reflecting arterial supply, renal cortical function, and patency of the renal collecting system. Quantitative radionuclide studies of the kidneys provide comprehensive, reproducible, and objective assessments of renal function.

Glomerular Filtration Rate

CT-SPECT fusion for analysis of radiolabeled antibodies: applications in gastrointestinal and lung carcinoma.

Fusing or image registration improves the information obtained by correlating images from various imaging modalities. We "fused" radiolabeled antibody SPECT with CT in patients with colorectal or lung cancer. We identified corresponding landmarks on cross-sectional images and used standard graphics algorithms for untilting to match planes of reconstruction and for two-dimensional warping or transformation of images or regions of interest. Fusing localizes activity on SPECT to specific anatomic structures and decreases SPECT false positives and CT false negatives.

Antibodies, Monoclonal

Hepatic hemangiomas: diagnosis with fusion of MR, CT, and Tc-99m-labeled red blood cell SPECT images.

A method of image analysis was developed for correlation of hemangiomas detected at computed tomography (CT) and/or magnetic resonance (MR) imaging with increased blood pool activity evident at single photon emission CT (SPECT) performed after labeling of red blood cells with technetium-99m. Image analysis was performed in 20 patients with 35 known hepatic hemangiomas. After section thickness and pixel sizes of the different studies were matched, intrinsic landmarks were chosen to identify anatomically corresponding locations. Regions of interest (ROIs) drawn on the CT and/or MR images were translated, rotated, and reprojected to match the areas of interest on the corresponding SPECT images by means of a two-dimensional polynomial-based warping algorithm. Analysis of ROIs on 30 SPECT-MR and 20 SPECT-CT pairs of registered images provided absolute confirmation that 34 suspected hemangiomas identified on SPECT images correlated exactly with lesions seen on CT and/or MR images. Accuracy of fusion was within an average of 1.5 pixels +/- 0.8 (+/- 1 standard deviation). The technique enabled diagnostic confirmation of hemangiomas as small as 1.0 cm and proved useful for evaluating lesions located adjacent to intrahepatic vessels.

Adult

Pulmonary applications of nuclear medicine.

Nuclear medicine techniques have a long history in pulmonary medicine, one that has been continually changing and growing. Even longstanding methods, such as perfusion scanning for embolic disease or for pretherapy pulmonary function evaluation, have largely withstood the test of recent careful scrutiny. Not only have these techniques remained an important part of the diagnostic armamentarium, but we have learned how to use them more effectively. Furthermore, because of technical advances, we are in a phase of expanding roles for nuclear imaging. Gallium citrate scanning for the mediastinal staging and follow-up of lymphoma has been recognized as a valuable adjunct to the anatomic information provided by CT and MRI. With the growth of PET technology in areas that have been explored in a limited fashion until now, such as noncardiogenic pulmonary edema and lung carcinoma, evaluation and management of these patients may substantially improve. Finally, in the field of radiolabeled monoclonal antibodies, attention is now being turned to both the diagnostic and the therapeutic problems presented by lung carcinoma. As radiolabeling methods are refined and as new and better antibodies are developed, radioimmunodetection and therapy in lung carcinoma may begin to make inroads on this common and hard to control disease.

Gallium Radioisotopes

Brain imaging in acquired immunodeficiency syndrome dementia complex.

Human immunodeficiency virus (HIV) infections are accompanied by many different types of neurological complications. Opportunistic infections and neoplasms, particularly lymphoma, are often an underlying cause for these complications in patients with acquired immunodeficiency syndrome (AIDS). Frequently, these can be detected by cerebrospinal fluid (CSF) examination, double-dose contrast transmission computed tomography (CT), and/or magnetic resonance imaging (MRI). It has become apparent that the HIV itself is responsible for a significant percentage of neurological disease in the HIV-seropositive individual. The onset may be subtle and may occur before the onset of frank immunosuppression. Diagnosis of HIV encephalitis or AIDS dementia complex (ADC) is complicated by the frequent coexistence of opportunistic infections. Structural neuroimaging (CT or MRI) shows atrophy and in some case white matter abnormalities, but imaging-pathological correlation suggests that these modalities are relatively insensitive to the presence of HIV brain infection. Functional neuroimaging, both 18fluorodeoxyglucose positron emission tomography (PET) for evaluation of glucose metabolism and 123I iodoamphetamine or 99mTc-HMPAO single-photon emission computed tomography (SPECT) for evaluation of cerebral perfusion, can demonstrate abnormalities in the subcortical gray matter structures and the cerebral cortex in patients with ADC. These abnormalities may be observed early in the course of ADC even when MRI is negative and the patient is relatively asymptomatic. Also, PET and SPECT may be useful to follow progression of the dementia or response to therapy.

AIDS Dementia Complex

Diagnostic implications of Ga-67 chest-scan patterns in human immunodeficiency virus-seropositive patients.

Consecutive gallium-67 scans (n = 237) of 180 human immunodeficiency virus-seropositive patients with suspected pulmonary infections were evaluated for intensity and pattern of gallium distribution. Scan findings were correlated with the history, chest radiographic findings, and clinicopathologic diagnoses. Pneumocystis carinii pneumonia (PCP) occurred significantly more often with heterogeneous diffuse uptake than with homogeneous diffuse uptake. Heterogeneous diffuse uptake had an 87% positive predictive value for PCP, which was higher than that of other patterns. Localized pulmonary uptake was most commonly due to bacterial pneumonia or PCP; ill-defined, perihilar uptake, to cytomegalovirus or PCP; and focal (lymph node) uptake, to tuberculosis or lymphoma. The positive predictive value of any pulmonary uptake for lung pathology was 93%, and the negative predictive value of a negative scan was 96%. These findings confirm the utility of gallium scanning in the detection of lung pathology related to acquired immunodeficiency syndrome, particularly PCP. Furthermore, identification of a diffuse pattern may permit the use of a less invasive test more specifically directed at the confirmation of a diagnosis of PCP.

Acquired Immunodeficiency Syndrome

CT-SPECT fusion to correlate radiolabeled monoclonal antibody uptake with abdominal CT findings.

To enhance the information provided by computed tomography (CT) and single photon emission computed tomography (SPECT) performed with radiolabeled, anti-carcinoembryonic antigen monoclonal antibody (MoAb), the authors performed fusion of these types of images from eight subjects with suspected colorectal adenocarcinoma. Section thickness and pixel size of the two studies were matched, coordinates of corresponding points from each study were identified, and CT sections were translated, rotated, and reprojected to match the corresponding SPECT scans. The CT-SPECT fusion enabled identification of anatomic sites of tumor-specific MoAb accumulation in four cases, showed non-specific MoAb accumulation in two, and helped confirm information only suggested by the two studies separately in one.

Adenocarcinoma

Detection of thoracic infections by nuclear medicine techniques in the acquired immunodeficiency syndrome.

The challenge of the acquired immunodeficiency syndrome (AIDS) for nuclear medicine has been the early detection of related intrathoracic opportunistic infections, inflammatory conditions, and neoplasms. Gallium-67 citrate scanning has proved a sensitive test not only for Pneumocystis carinii pneumonia but for many of the other opportunistic infections and malignancies, including mycobacterial infections and lymphoma. Patterns and intensity of gallium uptake may suggest more specific diagnoses. Indium-111-labeled white blood cells may also be a valuable diagnostic tool in the AIDS patient.

Acquired Immunodeficiency Syndrome

Split notochord syndrome with dorsal enteric fistula and sacral agenesis.

Split notochord syndrome of the lumbosacral spine in association with dorsal enteric fistula is a rare phenomenon. To date, only nine human cases have been reported in the English literature. We present another case of this type, with sacral agenesis as an additional and unique finding. Several etiological theories are discussed including the persistence of the neurenteric canal, the occurrence of an ectopic or accessory neurenteric canal, a division or local redundancy of the notochord, an entodermal-ectodermal adhesion, neural tube rupture caused by oversecretion of fluid, and failure or aberrancy of dorsal aortic distribution to the region of the neural folds resulting in prevention of timely neural tube closure.

Humans

Aortic aneurysm dissection causing V/Q mismatch.

A case of unilateral mismatch on a ventilation/perfusion lung scan due to aortic aneurysm dissection is presented. Pulmonary embolism should not be considered the sole cause of unilateral lung mismatch. Clinical evaluation and pulmonary angiography should be used for a definitive diagnosis.

Aortic Dissection

Contribution of SPECT to imaging of gastrointestinal adenocarcinoma with 111In-labeled anti-CEA monoclonal antibody.

Fourteen patients with suspected adenocarcinoma of the gastrointestinal tract received 1 mg of 111In-labeled anticarcinoembryonic antigen monoclonal antibody type ZCE025 combined with 40 mg unlabeled antibody of the same type. Planar and single-photon emission CT (SPECT) imaging studies were performed 3 days after infusion and, when possible, 7 days after infusion. Scan findings were correlated with the findings at surgery when possible. Tumor was detected by day-3 planar imaging in eight of 13 patients in whom tumor was documented histopathologically. Day-3 SPECT allowed demonstration of tumor in 11 of these 13 patients. In another patient whose scan was negative, no residual tumor was found at surgery. SPECT was particularly helpful in identifying small and midline tumors. In two cases, localization on SPECT helped identify the tumor mass on CT. Two primary tumors weighing less than 5 g could not be detected on either planar or SPECT scans. Histologically positive, normal-sized lymph nodes were not seen by planar imaging or SPECT. SPECT increased the detection rate over that achieved with planar imaging, helped to better localize scan abnormalities, and afforded more useful comparison between the monoclonal antibody study and CT.

Adenocarcinoma

The impact of intradermal lymphoscintigraphy on surgical management of clinical stage I truncal malignant melanoma.

Lymphoscintigraphy results in 35 stage I melanoma patients were compared with primary location and surgical management. Six of 25 primaries with potentially multidirectional lymphatic drainage had drainage to one regional node group. Three of 10 with expected unidirectional drainage showed multidirectional drainage. With unidirectional drainage, decision concerning lymphadenectomy was simplified.

Antimony

Gallium-67 scans of the chest in patients with acquired immunodeficiency syndrome.

Eighty-six [67Ga]citrate chest scans were performed in 71 adult patients with the acquired immunodeficiency syndrome. Forty-five of these patients also had Kaposi's sarcoma. Only 29 of 57 abnormal scans were correlated with abnormal chest radiographs. Chest radiographs were negative for 27 scans and unavailable for one. Several scan patterns were seen. Diffusely increased lung uptake was seen most commonly with Pneumocystis carinii pneumonia, but also other infections and noninfectious inflammatory conditions. Focal uptake corresponding to regional lymph node groups occurred most often with Mycobacterium avium-intracellulare but aslo with lymphoma. Localized intrapulmonary uptake was seen in bacterial pneumonias. Perihilar activity occurred in two cases. When chest radiographs were abnormal and 67Ga scans negative, the most common diagnosis was pulmonary Kaposi's sarcoma.

Acquired Immunodeficiency Syndrome

"Supernormal" bone image in a case of Waldenström macroglobulinemia.

A case of Waldenström macroglobulinemia, a rare cause of diffusely increased skeletal uptake and relatively diminished renal uptake of bone seeking radiopharmaceutical, is presented. This pattern has been described in a variety of disorders. An important observation to be made in these cases is the skeletal distribution of the radiopharmaceutical. In diffuse bone metastases from carcinoma, which is the most common cause of these findings, the increased activity is primarily in the axial skeleton. In some of the more uncommon causes, including certain hematologic disorders, however, the increased skeletal uptake is more homogeneous in distribution, with prominent uptake in the skull and distal extremities.

Aged