technetium-tc-99m-bicisate and Brain-Neoplasms

Radiotracers called chemical microsphere are widely accepted as brain perfusion agents. Following the intravenous administration, these drugs are transported via the artery to the brain, cross the intact blood-brain barrier, and enter the brain tissue. Once the tracer flows into the brain, the efflux of the tracer is prevented by some trapping mechanism, resulting in prolonged retention. Because the distribution of the accumulated tracer remains approximately consistent with regional cerebral blood flow for a relatively long period, high-quality SPECT images reflecting the distribution pattern of cerebral blood flow can be acquired. However, unlike true microsphere, cerebral kinetics of the brain perfusion agents is complicated, and various causes may produce discrepancy between the distributions of the tracer and blood flow. In this review, cerebral kinetics of the brain perfusion agents used commonly is discussed. The knowledge of the mechanism of brain accumulation appears to be essential to appropriately determine the tracer of choice and interpret the obtained images.

Topics: Amphetamines; Brain; Brain Neoplasms; Cerebral Infarction; Cerebrovascular Circulation; Cysteine; Humans; Iodine Radioisotopes; Iofetamine; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Technetium Tc 99m Exametazime

The dynamic 99Tcm-ethyl cysteinate dimer (99Tcm-ECD) single photon emission tomographic (SPET) characteristics of brain tumours were investigated and compared with 201Tl-chloride SPET indices. Thirty-five patients with histologically confirmed benign and malignant tumours were evaluated using dynamic and standard 99Tcm-ECD. Twenty-eight patients were also examined using standard 201Tl SPET. The following 201Tl indices were calculated: early uptake ratio, delayed uptake ratio, washout rate and retention index. The relationship between uptake of 99Tcm-ECD on dynamic SPET and 201Tl indices was analysed. Nine patients showed positive uptake on dynamic 99Tcm-ECD SPET, all of whom had benign tumours, including five meningothelial meningiomas, three pituitary adenomas of the chromophobe type and one chemodectoma without malignancy. The mean early uptake ratio of the tumours with positive uptake was significantly higher than that of the tumours with negative uptake (17.1 +/- 5.5 vs 9.0 +/- 5.7, P = 0.004). The mean washout rate of the tumours with positive uptake was significantly higher than that of the tumours with negative uptake (61.0 +/- 27.7 vs 0.35 +/- 30.9, P = 0.0004). The mean retention index of the tumours with positive uptake was significantly lower than that of the tumours with negative uptake (0.27 +/- 0.12 vs 0.88 +/- 0.48, P = 0.000006). Only benign tumours showed positive uptake on dynamic 99Tcm-ECD SPET. The 201Tl indices correlated well with the uptake of 99Tcm-ECD on dynamic SPET. The results suggest that dynamic 99Tcm-ECD SPET can identify the benign character of tumours of the brain.

Topics: Adult; Aged; Aged, 80 and over; Brain Neoplasms; Cysteine; Female; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

A 27-year-old man had complex partial seizures and a dysembryoplastic neuroepithelial tumor (DNT) in the left inferior-basal temporal region. The patient's seizures consisted of incomprehensible speech, staring, unresponsiveness, fumbling and then looking around. For the brain SPECT study, radiotracer was injected during the preictal (11s prior to seizure onset), ictal (at 25 s out of 47 s seizure duration) and interictal periods. Interictal SPECT was subtracted from preictal or ictal-injection SPECTs and then the subtracted SPECTs were overlaid on the patient's MRI (SISCOM). SISCOM with preictal-injection SPECT showed hyperperfusion at the brain lesion, whereas SISCOM with ictal-injection SPECT showed hyperperfusion at the ipsilateral amygdala-hippocampus and hypoperfusion around the tumor lesion. After the DNT and nearby temporal lobe tissues were resected with preservation of amygdala-hippocampus, the patient became seizure free without complaint of subjective postsurgical memory decline. In this patient, SISCOM with preictal injection of radiotracer localized an epileptogenic zone, whereas SISCOM with the ictal injection showed hyperperfusion at the symptomatogenic zone.

Topics: Adult; Brain Neoplasms; Cerebrovascular Circulation; Cysteine; Epilepsies, Partial; Humans; Magnetic Resonance Imaging; Male; Neoplasms, Neuroepithelial; Organotechnetium Compounds; Radiopharmaceuticals; Seizures; Tomography, Emission-Computed, Single-Photon

We performed 229 99Tcm-ethyl cysteinate dimer (ECD) single photon emission tomography (SPET) studies in 185 patients with brain tumour. Increased uptake of the tracer was observed in 11 cases. In six of these 11 patients, focal intense activity was seen in the area surrounding the tumour. Five of these six patients had episodes of seizure, and ictal SPET showed further increased uptake in the area of hyperperfusion in one patient. Hyperperfusion surrounding the tumour might be related to seizure. In the remaining five patients, increased accumulation was seen in the tumour. Three of these five patients had a discrepancy between 99Tcm-ECD SPET and 201Tl SPET imaging. There could be some difference in the mechanism of accumulation in the tumour between 99Tcm-ECD and 201Tl.

Topics: Adolescent; Adult; Aged; Astrocytoma; Brain; Brain Neoplasms; Cysteine; Female; Glioblastoma; Humans; Infant; Male; Meningioma; Middle Aged; Neoplasm Recurrence, Local; Oligodendroglioma; Organotechnetium Compounds; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

Two patients with Lhermitte-Duclos disease were evaluated by brain positron emission tomography (PET) and technetium-99m-ethyl cysteinate dimer (99mTc-ECD) single-photon emission computed tomography (SPECT). In the lesions in both patients, hyperperfusion was detected on cerebral blood flow images obtained by PET, and hyperactivity by standard 99mTc-ECD SPECT. Dynamic 99mTc-ECD SPECT images demonstrated a plateau of activity in each lesion. These findings suggest that lesions in Lhermitte-Duclos disease have a retention mechanism for 99mTc-ECD equivalent to that of normal neural tissue.

Topics: Adolescent; Adult; Brain; Brain Neoplasms; Cysteine; Female; Ganglioneuroma; Humans; Male; Organotechnetium Compounds; Tomography, Emission-Computed; Tomography, Emission-Computed, Single-Photon

The purpose of this study was to visualize the motor area related to finger movement and a fist-making task using SPECT in patients with lesions near the central sulcus.. Eleven patients (9 with a brain tumor, 1 with cerebral infarction, and 1 with an arteriovenous malformation) were investigated. The first intravenous injection of 99mTc-ethyl cysteinate dimer (ECD) for the motor activation SPECT images was administered 2 min after completion of the fist-making task with the hand contralateral to the brain lesion. The movement was stopped 2 min after injection, and activation SPECT was performed. After the scan, the second dose of 99mTc-ECD was injected into resting patients, and a second set of SPECT images was acquired. The first set of images was subtracted from the second set to obtain control images. Regions of interest were set bilaterally on the sensorimotor hand area; the supplementary motor area; the frontal, temporal, and occipital lobes; and the cerebellar hemispheres. The results of activation SPECT were expressed as positive or negative for a high-count area, and the regional percentage change for activation images relative to resting images was calculated.. Visual assessment of activation images was positive in 9 patients for the sensorimotor hand area and 7 patients for the supplementary motor area. The regional percentage change between activation and resting images for the high-count areas was 19.7% for the sensorimotor hand area and 18.2% for the supplementary motor area. Both values were significantly higher than those for other areas (P<0.05).. Motor activation SPECT using a 99mTc-ECD split-dose method is easy to perform and may be helpful for presurgical visualization and identification of the sensorimotor hand area or the supplementary motor area.

Topics: Brain Mapping; Brain Neoplasms; Cysteine; Female; Fingers; Humans; Male; Middle Aged; Motor Cortex; Movement; Neurosurgical Procedures; Organotechnetium Compounds; Preoperative Care; Radiopharmaceuticals; Tomography, Emission-Computed, Single-Photon

A 48-year-old man with carcinoma of the lung had loss of consciousness during radiation therapy and underwent 99mTc-ethyl cysteinate dimer (99mTc-ECD) SPECT to evaluate brain tumor seen on CT scan. Incidentally 99mTc-ECD SPECT imaging showed intense accumulation in the frontal and occipital bone. The tumor in the occipital bone had been histologically proven to be a metastasis from carcinoma of the lung. We presented a very rare case of bone metastasis demonstrating increased uptake of 99mTc-ECD.

Topics: Brain Neoplasms; Cysteine; Humans; Lung Neoplasms; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Skull Neoplasms; Tomography, Emission-Computed, Single-Photon

Discrepancies have been reported between the findings of Tc-99m HMPAO and Tc-99m ECD brain perfusion SPECT imaging. This study investigated the discrepancies in the accumulation of these tracers using dynamic SPECT to detect the super early phase of distribution. Thirteen patients with luxury perfusion or high flow states were studied with both dynamic and standard SPECT using Tc-99m HMPAO and Tc-99m ECD within 1-3 days. Standard SPECT showed discrepancies in 6 of 13 patients. Patients with meningioma and cerebral thrombosis had increased accumulation of Tc-99m HMPAO and decreased uptake of Tc-99m ECD. Patients with arteriovenous malformation, subarachnoid hemorrhage, and cavernous angioma had decreased accumulation of both tracers, but to different degrees. Dynamic SPECT showed increased or normal accumulation (i.e., essentially no discrepancy) in the first few minutes. However, Tc-99m HMPAO had a longer retention time than Tc-99m ECD in the ensuing 5-10 minutes. Dynamic SPECT revealed a similar accumulation pattern but different washout rates for the two tracers. Tc-99m HMPAO might be a more suitable tracer to detect high flow states or luxury perfusion because the findings on standard SPECT were more in agreement with those of dynamic SPECT using this tracer.

Topics: Adult; Aged; Brain; Brain Diseases; Brain Neoplasms; Cerebrovascular Circulation; Cerebrovascular Disorders; Cysteine; Female; Humans; Hyperemia; Male; Middle Aged; Organotechnetium Compounds; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon

For the evaluation of brain tumor (n = 15), we performed both dynamic and static 99mTc-ECD (ECD) SPECT studies 201Tl SPECT was also used for comparison with the results of ECD SPECT. Dynamic ECD SPECT was obtained following the injection of 600 MBq of ECD. Five min after the injection of ECD, static ECD SPECT was performed. 201Tl SPECT was obtained 10 min after the injection of 74MBq. Abnormal uptake was recognized in 7 of 15 tumors with dynamic ECD: 5 of 7 meningiomas, 1 of 1 glioblastoma and 1 of 1 astrocytoma. However, no abnormal uptake was seen in 3 of 3 benign tumors (1 low grade astrocytoma, 1 hemangioma, 1 cranio-pharyngioma) and in 2 of 2 brain metastases. In contrast abnormal uptake was seen in 11 of 15 tumors with 201Tl:7 of 7 meningiomas; 2 of 2 brain metastases, 1 of 1 glioblastoma and 1 of 1 craniopharyngioma. No abnormal uptake was seen in 3 of 3 benign tumors (1 hemangioma and 2 low grade astrocytomas). Equivocal uptake was seen in 1 low grade astrocytoma with dynamic ECD and 201Tl. The mechanism of the accumulation of dynamic ECD to brain tumor is unclear. However, it may reflect not only blood flow, but also metabolism.

Topics: Adult; Aged; Angiography, Digital Subtraction; Brain Neoplasms; Cysteine; Female; Humans; Male; Middle Aged; Organotechnetium Compounds; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

Among several brain radiopharmaceuticals for SPECT imaging, 99mTc complexes of HMPAO and ECD are the most widely used. They are considered to be equal in their capacity to reflect regional cerebral blood flow; but discrepancies between HMPAO and ECD brain uptake have been reported in stroke patients. This paper reports our observations regarding discrepancies between HMPAO and ECD SPECT in 14 of 23 patients with suspected brain tumors or presumed metabolic cerebral abnormalities. We obtained similar conflicting results, namely focal HMPAO hyperactivities and isoactive ECD SPECT. The majority of these discrepancies were found in patients with brain tumors (10 of 13 patients), while only 4 of the 10 remaining patients with nontumoral process showed similar discrepant results. The physiopathology behind these observations is discussed here, and it is likely to be related to the specific response to cellular metabolic disorders rather than to perfusion disturbances.

Topics: Adult; Aged; Aged, 80 and over; Brain Neoplasms; Coronary Circulation; Cysteine; Deoxyglucose; Female; Fluorine Radioisotopes; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

Topics: Aged; AIDS-Related Opportunistic Infections; Brain Ischemia; Brain Neoplasms; Cerebellar Neoplasms; Cerebral Infarction; Cysteine; Diagnosis, Differential; Fatal Outcome; Humans; Lymphoma, AIDS-Related; Male; Necrosis; Organotechnetium Compounds; Radiopharmaceuticals; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

We present a case of primary brain tumor demonstrating increased uptake of 99mTc-ECD. Astrocytoma (Grade II) showed significantly increased cerebral blood perfusion on dynamic images and homogeneously increased uptake on static images with 99mTc-ECD brain SPECT. There seems to be some difference in perfusion and mechanism of tumor uptake among the cerebral blood flow imaging agents (99mTc-ECD, 99mTc-HMPAO and [123I]-IMP) and 201TI-chloride.

Topics: Adult; Astrocytoma; Brain Neoplasms; Cerebrovascular Circulation; Cysteine; Frontal Lobe; Humans; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Thallium; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed

Visualization of cerebral perfusion with Single Photon Emission Computed Tomography (SPET) needs lipophil radiotracers which are able to cross the intact blood-brain-barrier (BBB); moreover local uptake must reflect regional cerebral blood flow. In the last decade many radiopharmaceuticals have been suggested and employed for this purpose. Recently a new molecule has been synthesized: technetium-99m-labeled ethyl cysteinate dimer (99mTc-ECD). Commonly, SPET of the brain with perfusion tracers is performed to identify ischemic regions. We describe a patient with a bulky cerebral metastasis, secondary to Hurthle cell carcinoma of the thyroid, which concentrated radioiodine. Brain metastases secondary to differentiated carcinoma of the thyroid are very rare and when treated with 131-I may provoke serious neurological problems. Therefore we decided to perform a brain SPET with 99mTc-ECD to exclude regional perfusion defects and deafferentation phenomena. Brain CT showed only the large metastasis. SPET images, reconstructed according to standard tomographic planes of the head: transverse, coronal and sagittal revealed no uptake of 99mTc-ECD within the metastasis and no regional perfusion defects related to compression phenomena or deafferentation. 99mTc-ECD has never been used to image cerebral neoplasm of whatever origin.

Topics: Adenocarcinoma; Aged; Brain Neoplasms; Cysteine; Female; Humans; Organotechnetium Compounds; Thyroid Neoplasms; Tomography, Emission-Computed, Single-Photon