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Biomedical subjects

S Ben-Haim

Publications and source records attributed to S Ben-Haim.

At least 19 recordsLinked to original sources
PubMed2006

PET/CT for atherosclerotic plaque imaging.

Atherosclerosis is one of the leading causes of morbidity and mortality in the world. Rupture of atherosclerotic plaques and thrombi formation are the primary mechanisms of myocardial infarction or cerebrovascular accident. Angiography is considered to represent the gold standard technique for imaging of the arterial lumen. However, in recent years it has been realized that the primary determinant of the atherosclerotic plaque stability is the composition of the plaque and other imaging modalities have been suggested. The purpose of this review is to briefly summarize the knowledge accumulated to present date regarding the potential role of fluodeoxyglucose imaging in the assessment of atherosclerosis and to compare this modality to additional available imaging approaches for the detection of vulnerable plaques.

Atherosclerosis↗
PubMed2004

The added value of spiral computed tomographic angiography after lung scintigraphy for the diagnosis of pulmonary embolism.

OBJECTIVES: The objectives of this study were to evaluate the added clinical value of spiral computed tomographic angiography (CTA) after ventilation-perfusion lung scintigraphy (V/Q) for the management of patients with suspected pulmonary embolism (PE). METHODS: Of 987 patients who had V/Q during 2001, 64 patients (6%) had CTA performed for further evaluation. V/Q and CTA findings were retrospectively analyzed by 2 clinicians who were blinded to the patients' outcome. Patient management was determined based on clinical and V/Q data and was reassessed after the addition of CTA data. RESULTS: CTA was performed in 2 patients with normal V/Q, 16 patients with low probability, 28 patients with intermediate, 4 patients with high probability, and 14 patients with nonconclusive V/Q. Three patients (19%) with low probability, 9 (32%) with intermediate probability, 4 (29%) with nonconclusive, and 4 (100%) with high probability V/Q had PE diagnosed by CTA. CTA findings changed the management in 2 patients (13%) with low probability, 15 (54%) with intermediate probability, and 4 (29%) with nonconclusive V/Q. CONCLUSION: In our institution, V/Q remains the main imaging modality for evaluation of patients with clinically suspected PE. CTA was performed after V/Q in 6% of patients. Patients with intermediate probability and those with nonconclusive V/Q, and to a much lesser extent, patients with low probability V/Q could benefit from the addition of CTA after V/Q. In patients with normal V/Q and those with high-probability V/Q, the addition of CTA does not seem to influence patient management.

Adolescent↗
PubMed2001

Three-dimensional electromechanical mapping: imaging in the operating room of the future.

BACKGROUND: Three-dimensional electromechanical mapping has previously been shown to be a clinically important tool for cardiac imaging and intervention. We hypothesized that this technology may be beneficial as an intraoperative modality for assessing cardiac hemodynamics and viability during cardiac surgery. We report here the use of this technology as an imaging modality for intraoperative cardiac surgery. METHODS: The tip of a locatable catheter connected to an endocardial mapping and navigating system is accurately localized while simultaneously recording local electrical and mechanical functions. Thus the three-dimensional geometry of the beating cardiac chamber is reconstructed in real time. The system was tested on 6 goats that underwent acute dynamic cardiomyoplasty and on 5 dogs that underwent left anterior descending (LAD) coronary artery ligation. RESULTS: The electromechanical mapping system provided an accurate three-dimensional reconstruction of the beating left ventricle during cardiomyoplasty. After the wrapping procedure, significant end-diastolic area reduction was noted in the base and mid parts of the heart (948 +/- 194 mm2 vs 1245 +/- 33 mm2, p = 0.021; and 779 +/- 200 mm2 vs 1011 +/- 80 mm2, p = 0.016). The area of the cross-section of the apex did not change during the operation. Acute infarcted tissue was characterized 3 days after LAD ligation by concomitant deterioration in both electrical and mechanical function. CONCLUSIONS: By providing both a clear view of the anatomical changes that occur during cardiac surgery, and an accurate assessment of tissue viability, electroanatomic mapping may serve as an important adjunct tool for imaging and analysis of the heart during cardiac surgery

Animals↗
PubMed2001

Novel magnetic technology for intraoperative intracranial frameless navigation: in vivo and in vitro results.

OBJECTIVE: To characterize the accuracy of the Magellan electromagnetic navigation system (Biosense Webster, Tirat HaCarmel, Israel) and to demonstrate the feasibility of its use in image-guided neurosurgical applications. DESCRIPTION OF INSTRUMENTATION: The Magellan system was developed to provide real-time tracking of the distal tips of flexible catheters, steerable endoscopes, and other surgical instruments, using ultra-low electromagnetic fields and a novel miniature position sensor for image-correlated intraoperative navigation and mapping applications. METHODS: An image registration procedure was performed, and static and qualitative accuracies were assessed in a series of phantom, animal, and human neurosurgical studies. EXPERIENCE AND RESULTS: During the human study phase, an accuracy error of up to 5 mm was deemed acceptable. Results demonstrated that this degree of accuracy was maintained throughout all procedures. All anatomic landmarks were reached with precision and were accurately viewed on the display screen. Navigation that relied on the system was also successful. No interference with operating room equipment was noted. The accuracy of the system was maintained during regular surgical procedures, using standard surgical tools. CONCLUSION: The system provides precise lesion localization without limiting the line of vision, the mobility of the surgeon, or the flexibility of instruments. Electromagnetic navigation promises new advances in neuronavigation and frameless stereotactic surgery.

Animals↗
PubMed2000

Response to repeated equal doses of epinephrine during cardiopulmonary resuscitation in dogs.

STUDY OBJECTIVE: Advanced cardiac life support (ACLS) guidelines recommend a 3- to 5-minute interval between repeated doses of epinephrine. This recommendation does not take into account the dose of epinephrine used, and only very limited data exist regarding the hemodynamic responses to repeated "high" doses of epinephrine. The objective of this study was to analyze the hemodynamic responses to repeated, equal, high doses of epinephrine administered during cardiopulmonary resuscitation (CPR) in a canine model of ventricular fibrillation (VF). METHODS: This study used a secondary analysis of data collected in a prospective, randomized study, primarily designed to assess the effects of acid buffers in a canine model of cardiac arrest. VF was electrically induced. After 10 minutes, CPR was initiated, including ventilation with FIO(2)=1.0, external chest compressions, administration of epinephrine (0.1 mg/kg repeated every 5 minutes) and defibrillation. Animals were randomized to receive either NaHCO(3), Carbicarb, tromethamine (THAM), or NaCl. The hemodynamic variables were sampled from each experiment's paper chart at 1-minute intervals, and the responses to the first 4 doses of epinephrine were compared. RESULTS: Thirty-six animals (9 in each buffer group) were included in this analysis. Systolic, diastolic, and coronary perfusion pressures increased steeply (by 100%, 130%, and 190%, respectively) only after the first epinephrine dose. These pressures peaked at 2 to 3 minutes and decreased only slightly and insignificantly during the rest of the 5-minute interval, until the next epinephrine dose. No further significant increases in arterial pressures were observed in response to the next 3 doses of epinephrine, administered 5 minutes apart. CONCLUSION: The hemodynamic effects of high-dose epinephrine (0.1 mg/kg) during CPR appear to last longer than 5 minutes. Therefore, longer intervals between doses may be justified with high doses of epinephrine.

Adrenergic alpha-Agonists↗
PubMed2000

False positive metaiodobenzylguanidine scan in a patient with a huge adrenocortical carcinoma.

We report a case of a 17-cm cortisol-secreting adrenocortical carcinoma in which [123I] metaiodobenzylguanidine (MIBG) scan showed accumulation of the isotope in the area of the tumor. Catecholamine levels were normal, and no chromaffin cells were found in histological examination of the tumor. A literature review of previously described cases of false positive MIBG scans in the adrenal region is offered. We conclude that MIBG scans might not be as specific as previously thought in differentiating pheochromocytoma from adrenocortical carcinoma. They should be performed only when clinical suspicion and abnormalities in catecholamines advocate the need.

3-Iodobenzylguanidine↗
PubMed2000

Kidney function after radical nephrectomy: assessment by quantitative SPECT of 99mTc-DMSA uptake by the kidneys.

UNLABELLED: To determine the function of the remaining contralateral kidney after the removal of a functioning kidney, 30 consecutive patients (18 men, 12 women; average age, 67 y; age range, 34-87 y) who were undergoing unilateral radical nephrectomy were evaluated by sequential quantitative 99mTc-dimercaptosuccinic acid (DMSA) SPECT (QDMSA) studies. METHODS: The 30 patients were undergoing radical nephrectomy for renal tumors. The first study was done before surgery. Follow-up studies were performed 2-23 mo after surgery. Clinical evaluations and determinations of serum creatinine level were performed at the same time as the QDMSA studies. RESULTS: The relative contribution of the resected kidneys to the global renal function before surgery was 43.2% +/- 7.3%. After surgery the uptake of the remaining kidney increased from 13.4% +/- 4.0% to 18.3% +/- 5.8% (t = 5.7; P = 0.0000). The relative function of the remaining kidney increased from 56.8% +/- 7.1% to 79.1% +/- 23.6% (t = 4.9; P < 0.0001) of the global renal function before nephrectomy. Increases in the renal volume (from 211 +/- 62 cm3 to 229 +/- 68 cm3; t = 4.5; P = 0.0001) and in the percentage injected dose per cubic centimeter (%ID/cm3) of the remaining kidney (from 0.066 +/- 0.02 % ID/cm3 to 0.085 +/- 0.03 %ID/cm3; t = 4.6; P = 0.0001) were associated with this change. Nine patients had 2 follow-up studies performed 3-4 mo after surgery and 12-14 mo after surgery. The volume of the remaining kidney (209.22 +/- 46.20 cm3 versus 217.88 +/- 58.85 cm3; t = 0.962; P = 0.364), the %ID/cm3 (0.09 +/- 0.016 %ID/cm3 versus 0.093 +/- 0.025 %ID/cm3; t = 0.362; P = 0.726), and the percentage uptake (19.26% +/- 4.45% versus 20.11% +/- 7.01%) did not change significantly between these 2 QDMSA studies. CONCLUSION: The results of this study suggest that adaptive changes causing hyperfunction of the remaining kidney may occur after nephrectomy of a functioning kidney in adults. These changes occur soon after surgery, persist for at least 1 y, and are evident on QDMSA studies.

Adaptation, Physiological↗
PubMed1998

Lower extremity scintigraphy: the foot and ankle.

Disorders of the ankle and foot are common and may pose a significant clinical problem. Acute injuries of the ankle and foot are routinely evaluated by radiographs and, if inconclusive, by magnetic resonance imaging (MRI) or computed tomagraphy (CT). In subacute or chronic injuries, where prolonged pain is unexplained, bone scintigraphy may play a significant role. The bone scan may differentiate soft tissue from bone pathology, and, being a sensitive test, it may indicate the region that needs further specific radiologic examination. It may also indicate the clinical significance of a radiologic finding. Moreover, in some clinical settings bone scintigraphy can be specific in the diagnosis. Careful attention to the technique enhances the efficiency of bone scintigraphy and SPECT allows better investigation of the hindfoot. The importance of ankle and foot injuries in the orthopedic practice and the better understanding of subacute and chronic injuries in athletes and in the general population has led to an increased use of specific tests such as MRI, CT, and bone scintigraphy. With improved technique and instrumentation it is no longer sufficient to indicate a focal abnormality in the ankle or foot on bone scintigraphy. More precise information about perfusion, blood pool, and specific location of a lesion can be obtained by high resolution and tomographic images. The role of bone scintigraphy in the diagnosis of such disorders will be presented with a focus on subacute traumatic injuries and related disorders, as well as its role in systemic inflammatory disorders that often involve the ankle and foot.

Ankle↗
PubMed1997

Benign proliferative lesions mimicking recurrence of Hodgkin's disease.

Salvage treatment in patients with recurrent Hodgkin's disease is more effective when tumor burden is minimal. That is why more intensive follow-up strategies, including frequent imaging tests, have been recently developed for the detection of early relapse. However, as screening procedures become more sensitive, there is an increasing risk of false-positive results, demonstrating nonmalignant proliferative disorders. We describe three young patients who had lymphocyte-predominant or mixed-cellularity Hodgkin's disease and were in clinical complete remission for 2.5-3 years after a combined treatment with chemotherapy and radiation. Imaging tests revealed new gallium-avid lymphadenopathy in the chest in two cases. Pathologically enlarged pelvic lymph nodes were identified in another case, after a diagnosis of recurrent disease in axilla. Those findings were interpreted as relapse, and the patients underwent thoracotomy and laparotomy, respectively, for histologic confirmation. The results showed progressively transformed germinal centers and sarcoid-like lesions, two benign proliferative disorders. When patients with Hodgkin's disease in remission show new lymphadenopathy, even with positive gallium scan, it seems mandatory to obtain tissue for histologic examination, even through invasive procedures such as laparotomy and thoracotomy, to avoid wrong diagnosis and unnecessary treatment.

Adult↗
PubMed1996

Diffuse lung uptake of Ga-67 after treatment of lymphoma: is it of clinical importance?

PURPOSE: To determine if diffuse lung uptake (DLU) of gallium-67 at scintigraphy in patients with lymphoma is indicative of lymphomatous involvement of the lungs. MATERIALS AND METHODS: Thirty-eight patients (24 male, 14 female; aged 15-76 years) with DLU were examined. The relation between DLU and lymphoma was investigated. Radiographic and computed tomographic findings and the persistence of Ga-67 uptake were investigated to detect lymphomatous involvement of the lungs. The relations between chemotherapy and radiation therapy, previous lung or heart disease, and DLU were also examined. RESULTS: DLU appeared only during or after chemotherapy. No clinical, radiologic, or follow-up evidence indicated that patients with DLU had active lymphomatous involvement of the lungs. The difference in survival between patients with persistent and patients with transient DLU was not statistically significant. No statistically significant correlation between DLU and any possible inductive factor was indicated at multivariate analysis. CONCLUSION: DLU after treatment does not indicate lymphomatous involvement of the lungs.

Adolescent↗
PubMed1996

Utility of gallium-67 scintigraphy in low-grade non-Hodgkin's lymphoma.

PURPOSE: Low-grade non-Hodgkin's lymphoma (LGNHL) has traditionally been considered non-gallium-avid. The sensitivity of gallium 67 (67Ga) scintigraphy when using modern equipment and techniques in patients with LGNHL was investigated. MATERIALS AND METHODS: Fifty-seven consecutive patients with LGNHL underwent 67Ga scintigraphy at initial presentation (n = 40), when tumor progression occurred during treatment (n = 3), and at suspected disease recurrence after continuous clinical remission (CCR) (n = 14). Planar and tomographic images were obtained with either a very large field-of-view or a dual-head digital camera. Of 45 patients with Ga-avid LGNHL, 30 underwent 93 follow-up scans (one to six studies per patient). Scan findings were correlated with clinical and computed tomographic (CT) findings and with patient outcomes. RESULTS: 67Ga scintigraphy was positive in 45 of 57 patients (sensitivity, 79%) and in 113 of 164 disease sites (sensitivity, 69%). The sensitivity was higher in the more common types of LGNHL: follicular, predominantly small cleaved cell (FSC), and follicular, mixed small cleaved and large cell (FM) (84% and 91% in patients and 72% and 71% in disease sites, respectively). Sensitivity was lower in patients with mucosa-associated lymphoid tissue lymphoma (MALT) and small lymphocytic lymphoma (SL). Among 28 patients with disease recurrence after CCR (14 with and 14 without baseline studies), 67Ga scan was positive in 25, for a sensitivity of 89% for detection of disease recurrence. CONCLUSION: When modern technology is used, 67Ga scintigraphy has good sensitivity in patients with LGNHL. It therefore can be used to monitor response to therapy and to provide early detection of disease recurrence in these patients.

Adult↗
PubMed1995

Utility of Tc-99m mebrofenin scintigraphy in the assessment of infantile jaundice.

Technetium-99m mebrofenin hepatobillary excretory patterns were assessed in 36 infants with hyperbilirubinemia. Phenobarbital was administered to 22 patients before imaging. Final diagnoses included: intrahepatic cholestasis (14 patients), neonatal hepatitis (nine patients), biliary atresia (eight patients), alpha-1-antitrypsin deficiency (two patients), Alagille's syndrome (two patients), and cystic fibrosis (one patient). No patient with biliary atresia showed bowel activity by 24 hours. Of the 28 infants without biliary atresia, 23 (82%) had bowel activity visualized by 6-8 hours and 26 (90%) had bowel activity by 24 hours. Two had no bowel activity at 24 hours: one had cystic fibrosis and one had neonatal hepatitis. Of the 26 patients with bowel visualization, the time to visualize bowel did not differ between patient groups with and without phenobarbital induction. All of the patients with hepatitis, including those with marked dysfunction, showed good hepatic uptake. Mebrofenin scintigraphy is an important imaging technique in the diagnostic evaluation of infants with hyperbilrubinemia. In addition to biliary atresia, intrahepatic cholestasis due to cystic fibrosis and severe neonatal hepatitis may also cause bowel nonvisualization up to 24 hours. The results of this study suggest phenobarbital induction may not be needed when Tc-99m mebrofenin scintigraphy is used for the assessment of infantile jaundice.

Aniline Compounds↗
PubMed1995

Gallium-67 scintigraphy in lymphoma with bone involvement.

UNLABELLED: Both Hodgkin's and non-Hodgkin's lymphoma (NHL) may involve bone. Traditionally, 99mTc-MDP bone scintigraphy has been used to detect such involvement. In recent years, 67Ga scintigraphy has shown to be useful in monitoring treatment response in lymphoma. Although 99mTc-MDP has not been found particularly useful for monitoring bone response to cancer treatment, we were interested in whether 67Ga scintigraphy and SPECT could be used to monitor bone involvement with lymphoma. METHODS: Gallium-67 and 99mTc-MDP uptake were investigated in 20 patients with lymphoma involving the bone before treatment. Gallium-67 scans were done in 16 patients for monitoring response to treatment in the bone lesions. RESULTS: Gallium-67 studies diagnosed bone lesions in 19 of the 20 patients. Technetium-99m-MDP detected bone lesions in all patients investigated. In four patients, uptake by Ga-67 was more intense than 99mTc-MDP and in another four patients 99mTc-MDP uptake was more evident. Gallium-67, however, was useful in detecting other regions of involvement in 18 of the 19 patients with soft-tissue lymphoma lesions. Gallium-67 scintigraphy also correctly monitored bone response to treatment in all but one of the 16 patients who had 67Ga scintigraphy after completing therapy. CONCLUSION: Gallium-67 uptake by lymphoma involving the bone can be used to monitor osseous response to treatment.

Adolescent↗
PubMed1994

Theoretical analysis predicts that respiratory sinus arrhythmia does not accurately measure efferent vagal activity during anesthesia.

The respiratory sinus arrhythmia (RSA) is an oscillation of cardiac cycle length (CCL) at the frequency of breathing. RSA is a non-invasive measure of efferent vagal activity, during controlled experimental conditions. Our goal is to assess whether existing theory predicts that RSA amplitude reliably measures efferent vagal activity during and after anesthesia. To do so we combine several existing mathematical models to predict the respiratory sinus arrhythmia. Computer simulation shows that for positive-pressure ventilation without spontaneous breathing efforts, increasing mean arterial pressure causes increase in efferent vagal activity, but not RSA amplitude. Therefore, for positive-pressure ventilation, RSA amplitude does not predict efferent vagal effects on CCL. In contrast, for spontaneous breathing, increasing mean arterial pressure causes increase in both efferent vagal activity and RSA amplitude. Therefore, during spontaneous breathing, RSA amplitude does predict efferent vagal activity. Nevertheless, RSA amplitude also depends on factors that have little effect on efferent vagal activity. For example, RSA amplitude is decreased by increasing respiratory rate or administering acetylcholinesterase and muscarinic antagonists. We conclude that current theory provides little or no justification for using RSA amplitude as a surrogate for efferent vagal activity during anesthesia.

Anesthesia, General↗
PubMed1994

Positron emission tomographic measurement of bone marrow blood flow to the pelvis and lumbar vertebrae in young normal adults.

Ten young normal adults had pelvic and lumbar vertebral body bone marrow blood flow examined using [15O]water and positron emission tomography (PET) in a study designed to assess the feasibility and reproducibility of the PET technique for measuring marrow blood flow to various marrow regions. The procedure was well tolerated. Repeated blood flow measurements obtained from two consecutive [15O]water exams on each individual subject were highly reproducible. In addition, there was minimal variation in marrow blood flow from individual to individual and no gender differences were noted. In contrast, mean +/- SD bone marrow blood flows (expressed as milliliters per minute per 100 g) at selected anatomical sites were significantly different and were as follows: lower lumbar vertebral bodies, 17.6 +/- 3.1; most posterior and superior pelvis (conventional site of percutaneous bone marrow biopsy), 14.3 +/- 3.1; and total superior pelvis, 11.1 +/- 2.0. We conclude that PET is a relatively noninvasive, simple, and reproducible technique for measuring bone marrow blood flow. Marrow blood flow is consistent between normal young subjects, but varies significantly between different anatomic regions of the marrow.

Adult↗