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Biomedical subjects

L Lamki

Publications and source records attributed to L Lamki.

At least 19 recordsLinked to original sources
PubMed2001

Potential pitfall in parathyroid sestamibi imaging resulting from a cardiac pacemaker.

A 47-year-old woman with a history of end-stage renal disease and hyperparathyroidism after total parathyroidectomy had Tc-99m sestamibi imaging to identify possible ectopic parathyroid tissue. This study was prompted by increasing calcium and parathyroid hormone levels after several years of taking calcium supplements necessitated by a surgically induced hypoparathyroid state and end-stage renal disease. The scan showed persistent linear activity in the upper right mediastinum in delayed images, after washout of the thyroid had occurred. Because of the unusual configuration of this finding, investigation of the patient's clinical history and other imaging studies was undertaken. The authors concluded that the unusual mediastinal uptake was not hyperactive parathyroid tissue, but rather was attributed to the presence of central venous pacemaker wires. Thus, this case illustrates a potential pitfall in parathyroid sestamibi imaging, the uptake of which may increase in the presence of a cardiac pacemaker, and it emphasizes the importance of correlative imaging.

Artifacts↗
PubMed2001

The "SAPHO" syndrome: a case report of a patient with unusual bone scan findings.

PURPOSE: The authors describe the clinical and bone scintigraphic findings of the SAPHO syndrome, which is characterized by synovitis, acne, palmoplantar pustulosis, hyperostosis, and osteitis. The case report illustrates the significance of bone scintigraphy in the diagnosis. It shows that Tc-99m MDP scanning can detect signs of arthritis not seen with other imaging methods, because the arthritis is inflammatory in nature and does not always cause bone erosion. Thus it is not visualized on plain radiographs. Knowledge of this disorder may help in the differential diagnosis of arthritis. MATERIALS AND METHODS: Tc-99m MDP bone scintigraphy was used to diagnose arthritic changes. Whole-body and multiple delayed spot images were obtained in a 39-year-old diabetic, hypertensive woman who had tenderness in the plantar aspect of her heels. Swelling of the small and large joints of the feet, ankles, knees, hips, right sacroiliac joints, and shoulders was noted. She also had hydradenitis suppurativa and a history of a previous episode in which the arthritis improved after surgical treatment for the hydradenitis. RESULTS: All active joint lesions were visualized on the bone scan, including the arthritis, which was not detected with other imaging methods. They were all well demonstrated in the bone scintiscan. The scan findings, along with the presence of hydradenitis, led to the correct diagnosis of SAPHO syndrome. CONCLUSION: Tc-99m MDP bone scanning may be helpful in diagnosing arthritis as associated with the SAPHO syndrome.

Acquired Hyperostosis Syndrome↗
PubMed2000

Carcinoembryonic antigen immunoscintigraphy complements mammography in the diagnosis of breast carcinoma.

BACKGROUND: An adjunctive noninvasive test that is predictable and highly specific for breast carcinoma would complement the high false-positive rate of mammography in certain patients. METHODS: This prospective, multicenter study evaluated the accuracy, safety, and immunogenicity of carcinoembryonic antigen (CEA) antibody imaging in women with known or suspected breast carcinoma. Scintigraphic breast images were obtained approximately 3-8 hours after the administration of technetium 99m ((99)Tc) labeled anti-CEA Fab' and correlated with histopathology. RESULTS: The (99)Tc labeled anti-CEA Fab' detected tumor CEA expression in 46 of 49 women (94%) initially entered with known primary breast carcinoma regardless of histology or serum CEA levels. In women scheduled for biopsy confirmation of mammographic and physical examination findings, 104 (99)Tc labeled anti-CEA Fab' studies had a sensitivity of 61% (17 of 28 cases) and a specificity of 91% (69 of 76 cases). In total, (99)Tc labeled anti-CEA Fab' detected 52 of 62 invasive ductal carcinomas, 5 of 5 invasive lobular carcinomas, and 3 of 6 noninvasive tumors (2 ductal carcinomas in situ and 1 intracystic papillary carcinoma). Tumor size significantly affected sensitivity (P = 0.041), with 11 of 14 missed lesions </= T1, and proliferative histology significantly affected specificity (P = 0.012), with 5 of 7 false-positive tumors being premalignant. In 50 breast carcinoma patients, (99)Tc labeled anti-CEA Fab' also demonstrated axillary lymph node involvement regardless of serum CEA levels, with a sensitivity of 80% when more than three lymph nodes were positive. No immune response or other meaningful side effects occurred. CONCLUSIONS: (99)Tc labeled anti-CEA Fab' had high specificity and positive predictive values for breast carcinoma and the majority of false-positive studies were associated with an increased risk of malignancy. Improved imaging techniques, including dedicated gamma cameras for breast and axillary lymph node imaging, will likely improve the test's sensitivity for smaller lesions.

Adult↗
PubMed2000

9:00-9:15. Antiangiogenic Treatment with Endostatin Results in Uncoupling of Blood Flow and Glucose Metabolism in Human Tumors.

Endostatin is a novel antiangiogenic agent currently in phase I trials. In the context of this trial, we are evaluating the use of non-invasive imaging with PET to determine the relationship between tumor blood flow and glucose metabolism in imaged tumors from treated patients.Ten patients have been treated with escalating daily iv Endostatin doses of 30 to 180 mg/m(2). PET images were obtained before the start of therapy and again after 28 days of treatment. Each patient was scanned with Oxygen-15 labeled water for estimation of tumor blood flow and Flourine-18 labeled FDG to estimate tumor metabolic activity. In most cases, two distinct tumor-bearing sites were analyzed in each patient. Thus, a total of 19 tumors were imaged. Regional blood flow and standard uptake values (SUV) were computed at baseline and 28 days post treatment and the percentage change in blood flow and SUV plotted as a function of Endostatin dose.Both blood flow and glucose metabolism in the imaged tumors were observed to increase in patients treated with </=60 mg/m(2)/d, but became uncoupled in the tumors imaged from patients treated at the 180 mg/m(2)/d dose level. Thus, in patients receiving Endostatin at a dose of 180 mg/m(2)/d, blood flow decreased but glucose metabolism increased. This relationship is displayed in Figure 1 below.

Journal Article↗
PubMed2000

9:30-9:45. First Pass FDG Measured Blood Flow in Tumors: A Comparison with O-15 Labeled Water Measured Blood Flow.

The purpose of this study was to determine if the first-pass of FDG can be used to measure regional blood flow in tumors in the absence of perfusion imaging with a known blood flow tracer.PET scans were obtained in patients being evaluated for tumor perfusion and metabolism in a Phase I dose escalating protocol for Endostatin, a novel antiangiogenic agent. A two minutes perfusion scan was done with a bolus injection of 60 mCi of O-15 labeled water followed by a 10 mCi dose of FDG and four sequential scans consisting of a first pass two minutes scan and three 15 minutes scans. Regions of interest were drawn on two tumor sites for each scan. Blood flow was computed using a one-compartment model previously published by the authors. Linear regression analysis was carried out between the first pass FDG measured blood flow and O-15 measured blood flow (Figure 1).Blood flow estimated from the first pass of FDG was linearly correlated with O-15 measured blood flow with an intercept of 0.01, slope of 0.86, and r squared regression coefficient of 0.74 (R = 0.86) for blood flow values of up to 0.6 ml/min/gm of tissue. These results suggests that in the absence of a perfusion tracer, the first pass of FDG provides an estimate of perfusion in a tumor within the limitations of incomplete extraction of FDG compared to O-15 water.

Journal Article↗
PubMed1999

Rapid diagnostic imaging of acute, nonclassic appendicitis by leukoscintigraphy with sulesomab, a technetium 99m-labeled antigranulocyte antibody Fab' fragment. LeukoScan Appendicitis Clinical Trial Group.

BACKGROUND: The purpose of this study was to evaluate the safety and efficacy of a technetium 99m-labeled antigranulocyte antibody Fab' fragment (sulesomab) as a diagnostic imaging agent in patients with suspected acute, nonclassic appendicitis. METHODS: This prospective multicenter trial involved 141 children and adults with suspected acute, nonclassic appendicitis. The investigators interpreted planar images acquired 15 to 30 minutes and 1, 2, and 4 hours after injection and also by single-photon emission computed tomography (SPECT). The imaging results were confirmed surgically, whereas nonsurgical patients were considered as not having appendicitis (intent to treat). RESULTS: Sulesomab had a sensitivity of 91% (29/32 patients) and a negative predictive rate of 97% for acute appendicitis. It detected additional abnormalities in 7 of 9 patients with other inflammatory abdominal disease and had a specificity of 92% (91/99 patients) and a positive predictive value of 80% for surgically confirmed right-lower-quadrant disease. In positive studies, 26% were identified by planar imaging at 15 to 30 minutes, 46% by 1 hour, 63% by 2 hours, and 71% by 4 hours; 29% required SPECT to detect the abnormality. Scanning time was 5 to 10 minutes per planar image and about 45 minutes for a SPECT study. Investigators found that sulesomab would have changed clinical management or reduced additional diagnostic studies in 64% of the patients. Adverse events were infrequent, minor, and self-limiting (9/141 patients, 6%). No human antimurine antibody response occurred in 48 evaluable patients. CONCLUSIONS: Sulesomab is safe, well-tolerated, and with no apparent immunogenicity. Focal inflammation or infection in the setting of suspected atypical appendicitis is rapidly and accurately detected. Management decisions incorporating sulesomab imaging potentially provide clear patient benefits, especially by correctly predicting surgery to be unnecessary in 97% of patients without acute appendicitis.

Abdominal Pain↗
PubMed1998

Isradipine prevents global and regional cocaine-induced changes in brain blood flow: a preliminary study.

The L-type calcium channel antagonist, isradipine, reduces brain ischemia in animal models of ischemic stroke. These effects of isradipine appear more pronounced in dopamine (DA) rich brain regions. These same DA-rich brain regions have also been shown to be the areas most affected by cocaine-induced ischemic changes. Using a novel quantified approach to single photon emission computerized tomography, we demonstrated that isradipine pre-treatment prevented cocaine-induced ischemic changes, especially in these DA-rich brain regions. This is the first demonstration that any medication, including isradipine, can prevent the ischemic effects of cocaine on brain blood flow. Isradipine may, therefore, be a useful therapeutic agent for the prevention of brain ischemia in cocaine addicts.

Adult↗
PubMed1998

Demonstration of dose-dependent global and regional cocaine-induced reductions in brain blood flow using a novel approach to quantitative single photon emission computerized tomography.

Ischemic stroke is a common cause of morbidity and mortality in cocaine addicts. Because the previous semiquantitative single photon emission computerized tomography (SPECT) method for measuring brain blood flow does not quantify blood flow, the magnitude and specificity of cocaine's effects during drug taking has not been well established. Here, using a novel quantitative approach to SPECT, we established that intravenous cocaine administration to nine recently abstinent cocaine-dependent subjects was associated with significant decreases in global and regional brain blood flow to dopamine-rich areas such as the prefrontal, frontal temporal, and subcortical gray matter. Establishing the utility of this relatively new quantitative SPECT technique provides an important tool for the management of vascular disorders of the brain. Additionally, identifying the site-specific effects of cocaine provides targets for the development of putative therapeutic medications to attenuate or minimize ischemic stroke in cocaine addicts.

Adolescent↗
PubMed1998

Augmented enterocystoplasty for neurogenic bladder associated with renal transplantation: appearance on Tc-99m MAG3 renal transplant scan.

Enterocystoplasty (bladder augmentation) is a method of increasing bladder capacity in patients with small or neurogenic bladders in order to prevent vesicoureteral reflux. In patients with poorly compliant bladders, enterocystoplasty, which consists of a segment of detubularized small bowel or a portion of the stomach attached to the bladder, often helps to reduce the intravesicular pressures, thus reducing the likelihood of infection. It is also useful in treating bladder dysfunction in children with end-stage renal disease who require renal transplantation. Radiographic evaluation of patients with a renal transplant and augmented bladder often can be confusing, and may suggest a urine leak or hematoma. We report a patient with a renal transplant, bladder augmentation, and rising serum creatinine who underwent renal scintigraphy and ultrasonography.

Adult↗
PubMed1998

The radiology of the thoracic manifestations of AIDS.

The thoracic manifestations of AIDS have undergone a gradual metamorphosis, partly due to more awareness about the disease leading to earlier diagnoses and partly due to the fact that research has produced more effective prophylaxis as well as treatment for these patients. Many patients now demonstrate partial or complete clinical response which prolongs the length and quality of life of individuals positive for the Human Immunodeficiency Virus (HIV+). Also, with the large number of infected individuals coming to medical attention, and the years of experience in diagnosing and treating these AIDS patients, we now recognize not only the usual but also less usual manifestations of thoracic illnesses in AIDS, including infections, non-infectious diseases such as HIV associated Lymphocytic Interstitial Pneumonia and the neoplasms associated with AIDS. A section will be devoted to HIV infection in children. We will finish the article with a discussion of the current role of Nuclear Medicine in the diagnosis of HIV associated thoracic diseases. These topics are the subject of this article.

AIDS-Related Opportunistic Infections↗
PubMed1997

Major histocompatibility complex class II antigen expression in rejecting cardiac allografts: detection using in vivo imaging with radiolabeled monoclonal antibody.

BACKGROUND: Increased expression of major histocompatibility complex class II (MHC-II) antigen occurs during cardiac allograft rejection. We tested the hypotheses that (1) radiolabeled antibody to MHC-II antigen allows detection of cardiac allograft rejection using nuclear imaging techniques and (2) uptake of radiolabeled antibody to MHC-II antigen correlates with severity of rejection. METHODS AND RESULTS: Thirteen beagles with cervical cardiac allografts were studied for 64+/-23 days by use of myocardial biopsy and in vivo imaging. Uptake of radiolabeled (131I [n=2], 123I [n=1], or 111In [n=10]) antibody to MHC-II increased over baseline in 7 animals that developed histological evidence of progressively worsening allograft rejection (group A), from 72.2+/-46.1 to 176.8+/-102.0 counts/pixel/mCi (P<.009). In 4 beagles without progressively worsening allograft rejection (group B), uptake was unchanged during follow-up (74.4+/-43.8 and 60.2+/-37.4 counts/pixel/mCi; P=NS). In animals studied with 111In-labeled antibody, uptake increased from 102.9+/-23.1 at baseline to 233.2+/-82.7 counts/pixel/mCi at follow-up in group A animals (P=.036), with no significant change in group B (91.1+/-34.9 and 75.9+/-24.9 counts/pixel/mCi; P=NS). Uptake of 111In-labeled antibody was 107.5+/-35.7, 135.9+/-70.8, and 307.8+/-90.1 counts/pixel/mCi in biopsy samples showing evidence of mild, moderate, and severe rejection, respectively (P=.001). Biopsy samples showing mild, moderate, and intense MHC-II expression antibody uptake had uptakes of 92.6+/-36.3, 158.5+/-54.7, and 307.8+/-90.1 counts/pixel/mCi, respectively (P=.00004). CONCLUSIONS: Radiolabeled monoclonal antibodies to MHC-II antigen can detect cardiac allograft rejection in this large mammal model of cardiac allograft transplantation, and this technique may have a potential role in the detection of rejection in patients after cardiac transplantation.

Animals↗
PubMed1995

Prominent small bowel Ga-67 uptake associated with Yersinial and tuberculous enterocolitis.

The nuclear medicine evaluation of the immunocompromised patient with fever of unknown origin may include the use of either labeled leukocytes or Ga-67 citrate, or both, in the search for an infectious focus. In recent years, labeled leukocytes (In-111 or Tc-99m) seem to have been employed preferentially by some. This is especially the case when the abdomen is a suspected site of involvement because of the normal colonic excretion of gallium that may complicate the interpretation of this study. The authors present the case of an immunocompromised patient with the interesting scintigraphic pattern of diffuse large and small bowel uptake of gallium secondary to biopsy proven Yersinia and tuberculous enterocolitis. A review of the recent literature reveals only one other similar case in which Yersinial disease was detected by Ga-67 scintigraphy. The present case illustrates that gallium's avidity for the atypical, less pyogenic, opportunistic infections common in immunocompromised patients justifies its continued use in such settings and, specifically, whenever tuberculosis is suspected.

Adult↗