PubMed Health⌕ Search

Biomedical subjects

T Siegal

Publications and source records attributed to T Siegal.

At least 19 recordsLinked to original sources
PubMed2006

Temozolomide treatment for newly diagnosed anaplastic oligodendrogliomas: a clinical efficacy trial.

PURPOSE: Chemotherapy with alkylating agents is of proven efficacy in recurrent anaplastic oligodendroglioma (AO) with reported response rates ranging between 50% and 70%. The response of newly diagnosed AO to initial treatment with temozolomide (TMZ) has not yet been reported. This study evaluated the response and time to tumor progression of newly diagnosed AO initially treated with TMZ. PATIENTS AND METHODS: Twenty patients with a median age of 47 (range: 26-65) received a median of 14 (range: 3-24) cycles of TMZ as their first modality of therapy following diagnosis of AO. Treatment was given every 28 days for 5 days at a starting dose of 200 mg/m2/d and was continued for 24 cycles unless toxicity or tumor progression required withdrawal of TMZ. MRI evaluations were repeated every 8 weeks and scales of Karnofsky performance status (KPS) and of neurological function were used to assess clinical response. RESULTS: Clinical improvement was observed in 60% of the patients with statistically significant gain measured by KPS and the neurologic function scales. The objective response rate was 75%, and median time to tumor progression was 24 months. Maximal objective response was reached within a median of 6 months (range: 3-12). Tumors with 1p loss had longer progression free survival compared to tumors without deletions (PFS at 24 months: 1p LOH = 100%, 1p intact = 20%; P = 0.057). TMZ was well tolerated with only two events of grade 3/4 hematological toxicity. CONCLUSIONS: Newly diagnosed AO demonstrates a high rate of response to initial therapy with TMZ, similar to the response reported for PCV combination therapy. Further studies are needed to determine the optimal duration of treatment and whether radiotherapy should immediately follow chemotherapy.

Adult↗
PubMed2006

EFNS Guidelines on diagnosis and treatment of brain metastases: report of an EFNS Task Force.

The objectives have been to establish evidence-based guidelines and identify controversies regarding the management of patients with brain metastases. The collection of scientific data was obtained by consulting the Cochrane Library, bibliographic databases, overview papers and previous guidelines from scientific societies and organizations. A tissue diagnosis is necessary when the primary tumor is unknown or the aspect on computed tomography/magnetic resonance imaging is atypical. Dexamethasone is the corticosteroid of choice for cerebral edema. Anticonvulsants should not be prescribed prophylactically. Surgery should be considered in patients with up to three brain metastases, being effective in prolonging survival when the systemic disease is absent/controlled and the performance status is high. Stereotactic radiosurgery should be considered in patients with metastases of 3-3.5 cm of maximum diameter. Whole-brain radiotherapy (WBRT) after surgery or radiosurgery is debated: in case of absent/controlled systemic cancer and Karnofsky Performance score of 70 or more, one can either withhold initial WBRT or deliver early WBRT with conventional fractionation to avoid late neurotoxicity. WBRT alone is the treatment of choice for patients with single or multiple brain metastases not amenable to surgery or radiosurgery. Chemotherapy may be the initial treatment for patients with brain metastases from chemosensitive tumors.

Advisory Committees↗
PubMed2005

Central nervous system involvement in indolent lymphomas.

BACKGROUND: Central nervous system (CNS) involvement, a well-recognized complication of aggressive non-Hodgkin's lymphomas (NHL), has rarely been reported in indolent lymphomas. Large series have reported this complication in 3% of indolent NHLs, generally following histological transformation. PATIENTS AND METHODS: We retrospectively reviewed the disease characteristics and clinical course in seven patients (six females, one male) with indolent B-cell lymphomas who developed CNS involvement during various stages of their illness. RESULTS: The median ages at diagnosis of systemic and CNS lymphoma were 60 and 63 years, respectively. Histologies were: small lymphocytic lymphoma (two), follicular lymphoma grade I (two), follicular lymphoma grade II (two) and unclear low-grade histology (one). There were diverse neurological symptoms. Two patients had parenchymal involvement, three had leptomeningial involvement and two had both. Systemic lymphoma was found in all patients, all but one having bone marrow involvement. Four patients had a transformation to high-grade histology. Six patients were treated with systemic and intra-cerebrospinal fluid chemotherapy, and two received radiotherapy as well. Five patients achieved CNS response. Survival was 1-9 years for treated patients (median 2 years). Three patients died of CNS disease. CONCLUSIONS: CNS involvement is a rare and unexpected complication of indolent NHL, which should be considered in the differential diagnosis of patients presenting with new neurological signs. This condition is treatable and some patients have a long clinical course.

Adult↗
PubMed2001

Importance of dose intensity in neuro-oncology clinical trials: summary report of the Sixth Annual Meeting of the Blood-Brain Barrier Disruption Consortium.

Therapeutic options for the treatment of malignant brain tumors have been limited, in part, because of the presence of the blood-brain barrier. For this reason, the Sixth Annual Meeting of the Blood-Brain Barrier Disruption Consortium, the focus of which was the "Importance of Dose Intensity in Neuro-Oncology Clinical Trials," was convened in April 2000, at Government Camp, Mount Hood, Oregon. This meeting, which was supported by the National Cancer Institute, the National Institute of Neurological Disorders and Stroke, and the National Institute of Deafness and Other Communication Disorders, brought together clinicians and basic scientists from across the U.S. to discuss the role of dose intensity and enhanced chemotherapy delivery in the treatment of malignant brain tumors and to design multicenter clinical trials. Optimizing chemotherapy delivery to the CNS is crucial, particularly in view of recent progress identifying certain brain tumors as chemosensitive. The discovery that specific constellations of genetic alterations can predict which tumors are chemoresponsive, and can therefore more accurately predict prognosis, has important implications for delivery of intensive, effective chemotherapy regimens with acceptable toxicities. This report summarizes the discussions, future directions, and key questions regarding dose-intensive treatment of primary CNS lymphoma, CNS relapse of systemic non-Hodgkin's lymphoma, anaplastic oligodendroglioma, high-grade glioma, and metastatic cancer of the brain. The promising role of cytoenhancers and chemoprotectants as part of dose-intensive regimens for chemosensitive brain tumors and development of improved gene therapies for malignant gliomas are discussed.

Adult↗
PubMed2000

Safety and efficacy of a multicenter study using intraarterial chemotherapy in conjunction with osmotic opening of the blood-brain barrier for the treatment of patients with malignant brain tumors.

BACKGROUND: The aim of this study was to determine the safety and efficacy of intraarterial chemotherapy with osmotic opening of the blood-brain barrier (BBB) for the treatment of malignant brain tumors when administered across multiple centers. METHODS: Patients with primary central nervous system lymphoma (PCNSL), primitive neuroectodermal tumor (PNET), germ cell tumor, cancer metastasis to the brain, or low or high grade glioma were eligible. Prior to entry, magnetic resonance imaging or computed tomography brain scan, medical history, neurologic status, and Karnofsky performance status were reviewed at the coordinating center. Standardized anesthesia and intraarterial catheterization guidelines were followed by a multidisciplinary team at each center. Between March 1994 and November 1997, 5 universities treated 221 adult patients with intraarterial chemotherapy with or without osmotic opening of the BBB (2464 procedures). RESULTS: Of evaluable patients with PCNSL, 40 of 53 (75%) achieved complete response (CR). All evaluable patients with PNET (n = 17), metastatic disease (n = 12), or germ cell tumor (n = 4) achieved stable disease (SD) or better. Of 57 evaluable patients with glioblastoma multiforme, 45 (79%) achieved SD or better. Asymptomatic subintimal tear occurred in 11 of 221 patients (5%), pulmonary embolism in 6 of 221 (2.7%), and renal toxicity in 4 of 221 (1.8%). One patient with extensive glioma expired within 48 hours after treatment. CONCLUSIONS: Using standard guidelines and protocols, intraarterial chemotherapy with or without osmotic opening of the BBB is feasible across multiple centers with a low incidence of catheter-related complications. In patients with chemotherapy-sensitive tumors, such as PCNSL, PNET, germ cell tumor, and cancer metastasis to the central nervous system, enhanced delivery results in a high degree of tumor response, with an efficacy profile that is reproducible across multiple centers.

Adult↗
PubMed2000

Pharmacokinetics of methotrexate in cerebrospinal fluid and serum after osmotic blood-brain barrier disruption in patients with brain lymphoma.

OBJECTIVE: To evaluate the pharmacokinetics of methotrexate in ventricular cerebrospinal fluid and serum after osmotic blood-brain barrier disruption and intra-arterial administration compared with intravenous or simple intra-arterial infusion in patients with primary central nervous system lymphoma. METHODS: Serum and ventricular cerebrospinal fluid were sampled after methotrexate administration in 12 patients. Blood-brain barrier disruption was induced on 2 sequential days by mannitol (25%) infusion delivered to the vertebral or internal carotid artery territories followed by intra-arterial methotrexate (dose, 1.4 g/m2; 47 treatments). Sixteen treatments were given without barrier disruption by intravenous (3.5 g/m2; nine treatments) or intra-arterial (2.8 g/m2; seven treatments) infusion. RESULTS: Ventricular cerebrospinal fluid-methotrexate peak levels after blood-brain barrier disruption of the vertebral and the internal carotid arteries territories were 19.3 +/- 2.9 and 8.5 +/- 0.7 micromol/L (P < .001), and the area under the curve from time 0 to infinity was 178.0 +/- 21.3 and 110.0 +/- 12.4 [micromol/L x h, respectively (P < .01). No significant differences were observed in serum levels. After intra-arterial infusion was performed without disruption, the serum peak level was higher than that achieved by intravenous treatment (518.2 +/- 67.7 versus 180.6 +/- 31.8 micromol/L; P < .001). No differences were observed in cerebrospinal fluid concentrations, which dropped below 1 micromol/L at 6 hours. The cerebrospinal fluid/serum ratio [AUC(%)] of methotrexate after blood-brain barrier disruption was three to four times greater than that by systemic administration. CONCLUSION: Enhanced methotrexate delivery to the central nervous system can be attained by intra-arterial administration combined with osmotic disruption of the blood-brain barrier compared with simple intra-arterial or intravenous administration.

Adult↗
PubMed2000

In vivo assessment of the window of barrier opening after osmotic blood-brain barrier disruption in humans.

OBJECT: Osmotic blood-brain barrier (BBB) disruption induced by intraarterial infusion of mannitol is used in conjunction with chemotherapy to treat human brain tumors. The time course to barrier closure, or the so-called therapeutic window, has been examined in animals but little information is available in humans. The authors, therefore assessed the time course to barrier closure after osmotic BBB disruption in humans. METHODS: Disruption of the BBB was demonstrated using 99mTc-glucoheptonate (TcGH) single-photon emission computerized tomography (SPECT) scanning in 12 patients who were treated monthly with combination chemotherapy in conjunction with BBB disruption. The primary diagnosis was primary central nervous system lymphoma in seven patients and primitive neuroectodermal tumors in five. The TcGH (20 mCi) was injected at 1- to 480-minute intervals after osmotic BBB disruption, and patients underwent SPECT scanning after 4 hours. A total of 38 studies was performed. Good-to-excellent BBB disruption was obtained in 29 procedures and poor-to-moderate disruption was seen in the other nine studies. The TcGH indices correlated with the degree of BBB disruption as measured postprocedure on contrast-enhanced CT scans (r = 0.852). Mean baseline TcGH indices were 1.02+/-0.07. For the group of patients with good-to-excellent disruptions the mean indices at 1 minute postdisruption measured 2.19+/-0.18. After 40 minutes no significant change was noted (mean index 2.13+/-0.2). Then the indices declined more steeply and at 120 minutes after the disruption the index was 1.36+/-0.02. A very slow decline was noted between 120 and 240 minutes after mannitol infusion. At 240 minutes the barrier was still open for all good-to-excellent disruptions (index 1.33+/-0.08) but at 480 minutes the mean indices had returned to the baseline level. CONCLUSIONS: Results of these in vivo human studies indicate that the time course to closure of the disrupted BBB for low-molecular-weight complexes is longer than previously estimated. The barrier is widely open during the first 40 minutes after osmotic BBB disruption and returns to baseline levels only after 6 to 8 hours following the induction of good or excellent disruption. These findings have important clinical implications for the design of therapeutic protocols.

Adult↗
PubMed1999

Graft-versus-lymphoma effect after allogeneic peripheral blood stem cell transplantation for primary central nervous system lymphoma.

Allogeneic peripheral blood stem cell transplantation (allo PBSCT) is a recognized treatment modality for hematological malignancies resistant to conventional chemoradiotherapy. The post-transplant immune-mediated graft-versus-leukemia effect has major curative potential. In this case presentation, the allogeneic approach to resistant recurrent primary central nervous system (CNS) lymphoma using peripheral blood stem cells from an HLA identical sibling after immuno-suppressive non-myeloablative conditioning, was examined clinically. The patient in question had relapsing refractory primary CNS lymphoma and is the first to be treated with this modality. She developed early skin and liver-localized grade II graft-versus-host disease after allo PBSCT, which then responded to short-term treatment. Chimeric studies at the time showed 100% donor cells and repeated magnetic resonance imaging of the brain revealed gradual shrinkage of the tumor. Three months after transplant the cerebral mass was no longer evident and currently, 30 months after transplantation, the patient continues to be disease free. The absence of any signs of malignancy suggests the development of a durable graft-versus-lymphoma effect in this brain tumor and indicates that this effect may be achieved even after non-myeloablative conditioning.

Adult↗
PubMed1998

Leptomeningeal metastases from solid tumors: a comparison of two prospective series treated with and without intra-cerebrospinal fluid chemotherapy.

BACKGROUND: It has been suggested that an aggressive treatment of patients with leptomeningeal metastases (LM) that groups radiotherapy and intra-cerebrospinal fluid (intra-CSF) chemotherapy has improved treatment outcomes. Based on their previous series of 137 patients treated with such an intensive standard protocol, the authors expected 20% of the patients to maintain their responses for at least 6 months after withdrawal of therapy. They also observed that, in patients with solid tumors, a partial response was compatable with sustained off-therapy response and that the maximal response was reached soon after completion of radiotherapy. The authors concluded that the role of intra-CSF chemotherapy, with its associated high rate of complications, is unclear. In this study, which was a further evaluation of this dilemma, they compared the outcomes of two prospective treatment protocols that were identical in their use of radiotherapy and systemic chemotherapy and varied only in their inclusion or exclusion of intra-CSF chemotherapy. METHODS: Adult patients with LM from systemic solid tumors were prospectively included in the treatment protocol active at the time of their diagnosis. Group 1 comprised 54 patients treated by radiotherapy, intra-CSF chemotherapy, and systemic therapy, whereas Group 2 comprised 50 patients treated with radiotherapy, and systemic chemotherapy but no intra-CSF chemotherapy. RESULTS: The analysis of treatment outcomes was performed retrospectively. The median patient age and distribution of primary neoplasms did not differ between the two groups. The proportion of early deaths that occurred during radiotherapy was similar for the two groups, as was the overall rate of response to treatment. The two groups also had the same median survival, which was 4 months for both groups, as well as the same proportion of long term survivors. Thirty-one percent of patients in Group 1 developed early complications related to intra-CSF chemotherapy, whereas patients in Group 2 were spared these complications. Delayed symptomatic leukoencephalopathy was observed in 20% of Group 1 patients compared with none in Group 2 (P = 0.02). CONCLUSIONS: The exclusion of intra-CSF chemotherapy from the treatment schedule of patients with LM does not change their overall response to treatment, their median survival, or the proportion of long term survivors. It does, however, significantly reduce the rate of early and delayed treatment-related complications.

Adult↗
PubMed1998

Leptomeningeal metastases: evaluation by gadolinium enhanced spinal magnetic resonance imaging.

BACKGROUND: Leptomeningeal metastases are common in patients with metastatic systemic cancer or certain primary brain tumors. They may be unsuspected clinically and may be missed by cerebrospinal fluid (CSF) cytology. We undertook a retrospective study of the diagnostic value of gadolinium enhanced spinal MR imaging in patients with known or at high risk for leptomeningeal metastases (LM). MATERIAL AND METHODS: Ninety-six gadolinium enhanced MR examinations of the whole spine were performed in 61 patients (26 primary central nervous system tumors, 20 solid tumors and 15 lymphoproliferative neoplasms). All patients had detailed neurological evaluation and concomitant CSF examination. RESULTS: Sixty-one MR's (62%) were positive, mostly in the lumbar spine. MR's were positive in 92% of patients with positive initial CSF cytology and in 60% of patients with negative CSF cytology. The MR examination was positive in 49% of those without clinical findings related to the spinal region. It showed disease beyond the symptomatic level in 42% of patients with spinal symptomatology. Multi-level spinal involvement was present in 57% of positive MR exams. CONCLUSION: Enhanced spinal MR is sensitive for the detection of neoplastic spinal seeding. It detects LM in about 50% of high risk patients with negative initial CSF cytology or no spinal symptoms.

Adult↗
PubMed1997

The central visual field in homonymous hemianopia. Evidence for unilateral foveal representation.

BACKGROUND: Controversy exists regarding the cortical representation of the foveal region in man. The most plausible explanation for foveal sparing in homonymous hemianopia is dual blood supply to the occipital pole. However, bilateral cortical representation has also been suggested. OBJECTIVE: To determine the representation of the foveal region in the primary human visual cortex. DESIGN: A case series correlating magnetic resonance imaging to the visual field defects of 6 patients with occipital lobe injuries. RESULTS: Four patients with foveal-sparing hemianopic defects demonstrated unilateral sparing of the posterior occipital cortex. In contrast, 2 patients with central homonymous defects showed isolated involvement of the posterior pole. One patient also demonstrated 5 degrees of field sparing along the horizontal meridian. CONCLUSIONS: On the basis of correlating the findings of magnetic resonance imaging and visual field defects in patients with occipital lobe injury, we conclude that the foveal region is unilaterally represented in the primary human visual cortex and that a major portion of the striate cortex is dedicated to the central 10 degrees of vision. The horizontal meridian of the visual field is represented deep within the calcarine banks at the fissure base.

Adult↗
PubMed1997

Utility of relative cerebral blood volume mapping derived from perfusion magnetic resonance imaging in the routine follow up of brain tumors.

It was recently demonstrated that imaging of brain tumors by relative cerebral blood volume (CBV) maps reconstructed from dynamic magnetic resonance (MR) data provide similar diagnostic information compared to positron emission tomography (PET) or 201Tl single-photon emission computerized tomography (201Tl-SPECT) scans. The authors used relative CBV mapping for routine follow-up evaluation of patients with brain tumors and compared its sensitivity to diagnostic MR imaging, 201Tl-SPECT and clinical assessment. Fifty-nine patients were prospectively followed using 191 concomitant studies of dual section relative CBV maps, MR imaging, 201Tl-SPECT, and neurological evaluations. Studies were repeated every 2 to 3 months (median three evaluations/patient). The relative CBV maps were graded as relative CBV 0 to 4, where Grades 3 and 4 are indicative of proliferating tumors (four = rapid leak). There were 44 high-grade and 15 low-grade tumors followed during treatment. During the follow-up period a change in relative CBV grade was observed in 56% of the patients, revealing an increasing grade in 72% of them. The rapid leak phenomenon was detected in 35% of all studies and in 81% of those with a worsening relative CBV grade. Tumor progression was detected earlier by relative CBV maps as follows: earlier than MR imaging in 32% of the studies (earlier by a median of 4.5 months; p < 0.01); earlier than 201Tl-SPECT in 63% (median 4.5 months; p < 0.01), and earlier than clinical assessment in 55% (median 6 months; p < 0.01). In 82% of studies with positive MR imaging but negative 201Tl-SPECT, the lesions were smaller than 1.5 cm. The relative CBV maps clearly delineated the appearance of rapid leak in these lesions. Routine use of relative CBV maps that can be implemented on any high-field MR unit and added to the regular MR evaluation provides useful functional information in patients with brain tumors. When used as an adjunct follow-up evaluation it proved more sensitive than the other modalities for early prediction of tumor growth. It is very sensitive to small regional changes, unlike functional imaging such as PET or SPECT scans. Based on previous experience with 76 regional CBV studies, the authors conclude that regional CBV mapping correlates with active tumor and it may separate enhancing scar and radiation injury from infiltrative tumor. A new effect named the rapid leak phenomenon was also observed; this phenomenon, as identified on the regional CBV maps, correlates with high malignancy.

Adolescent↗
PubMed1996

Cellular and secretory mechanisms related to delayed radiation-induced microvessel dysfunction in the spinal cord of rats.

PURPOSE: This study aimed to investigate long-term, radiation-induced changes in microvessel permeability, the profile of the vasoactive mediators endothelin and nitric oxide, and the response of specific cell systems in the irradiated spinal cord of rats. METHODS AND MATERIALS: The thoracolumbar spinal cords of Fischer rats were irradiated to a dose of 15 Gy, and the rats were sacrificed at various times afterward. Endothelin levels and nitric oxide-synthase (NOS) activity were assayed in extracts of spinal cords. Microvascular permeability and the effect of treatment with recombinant human manganese superoxide dismutase (r-hMnSOD) were assessed quantitatively. Immunohistochemistry evaluated astrocytes, microglia, vascular basal membrane, and neurofilaments. RESULTS: None of the rats developed neurologic dysfunction. Endothelin levels were significantly reduced at 18 h after irradiation and markedly attenuated after 10 days (p < 0.007). Thereafter, endothelin levels returned to normal values at 56 days after radiation and escalated to markedly high levels after 120 and 180 days (p < 0.002). NOS activity remained very low throughout the period of follow-up and failed to counterbalance the shifts in endothelin levels. Treatment with r-hMnSOD had no effect on normal vascular permeability but it abolished the abnormally increased permeability measured at 18 h after radiation and again after 120 and 180 days. Standard microscopic evaluation failed to reveal abnormalities in the irradiated spinal cord, but immunohistochemical staining showed a progressive increase in the number of microglial cells per field after 120 and 180 days (p < 0003). A similar increase in the number of astrocytic cells per field was noted after more than 180 days, but an earlier short lasting peak was also noted at 14 days after radiation. No abnormalities were found in blood vessel configuration, density, diameter, and basal membrane staining, or in the neurofilaments. CONCLUSION: Marked imbalance in the regulatory function of endothelium-derived mediators of the vascular tone is present after radiation therapy probably inducing chronic vasoconstriction. This imbalance favors localized procoagulation that may enhance the consequent loss of function measured as increased permeability. Microglial proliferation may account for continuous release of superoxide that may enhance disruption of normal permeability. The latter is corrected by SOD treatment. Astrocytic proliferation may present a response to the mitogenic effect of endothelin and to microglial-derived paracrine effect of cytokines.

Animals↗
PubMed1996

Electric shock-like sensations in 42 cancer patients: clinical characteristics and distinct etiologies.

We retrospectively evaluated 42 consecutive cancer patients manifesting electric shock-like sensations. Fourty three percent presented with Lhermitte's sign (LS), 24% with the previously described outstretching ir. abduction maneuver (OAM) of the arms, and 33% had both phenomena. Twenty nine patients had underlying polyneuropathy related to cisplatin-based chemotherapy in 27 and to thiamine deficiency in 2. Thirtreen patients had myelopathy which was induced by radiotherapy in 11. Patients with polyneuropathy manifested both LS and OAM, while patients with myelopathy more often presented with LS. Neurologic signs suggestive of spinal cord involvement were present in 3 patients with polyneuropathy and in 7 of 11 irradiated patients. MRI disclosed cervical spinal cord swelling in 3 patients with LS. Prolonged cervical latencies on SSER were noted in 5 of 15 patients. All had LS and 3 also had OAM associated with abnormal latencies in the brachial plexi. We conclude that LS and OAM are positive sensory manifestations of increased mechanosensitivity of the damaged central or peripheral sensory axons in the cervico-brachial area. In cancer patients, these phenomena largely manifest treatment-induced myelopathy or polyneuropathy. Auxillary studies help to confirm diagnosis and to depict the uncommon but treatable causes.

Adult↗
PubMed1996

Use of 201Thallium brain SPECT, image registration, and semi-quantitative analysis in the follow-up of brain tumors.

OBJECTIVE: To assess the use of 201Thallium SPECT and of Thallium (Tl) uptake indices in the detection and follow-up of cerebral tumors. MATERIAL AND METHODS: Two-hundred eighty 201Tl, 135 99mTc-HMPAO scintigraphies and 280 MRI studies were acquired in 135 patients with cerebral tumors. Three types of Tl uptake indices were calculated by establishing the ratio of the lesion activity to an homologous ROI (I1), the contralateral hemisphere (I2), and the contralateral scalp (I3). Intermodal coregistration between Tl-SPECT and MRI when used, was performed using Pietrzyk visual interactive method. RESULTS: Tl uptake indices showed mean values of 2.0 +/- 0.5 (I1); 1.77 +/- 0.57 (I2) and 1.11 +/- 0.40 (I3) in positive scans, and of 1.05 +/- 0.22 (I1), 0.88 +/- 0.22 (I2) and 0.50 +/- 0.15 (I3) in negative scans, respectively. A linear combination of the two less correlated indices lead to a more powerful discrimination between positive and negative studies. Longitudinal follow-up studies in the same patients showed good concordance between the index values and the course of the disease. CONCLUSION: The use of Tl uptake indices improves the accuracy of Tl-SPECT in the follow-up of brain tumors.

Adolescent↗