Evaluation of the lung uptake of 123I-IMP by bronchoalveolar lavage

A 67-year-old female with radiation pneumonitis in the right upper lobe underwent lung scanning and bronchoalveolar lavage 4 hours after the intravenous injection of 123I-IMP. The lung scanning showed increased accumulation of 123I-IMP, corresponding with the area of radiation pneumonitis. The ratios of radioactivities of the cellular and noncellular components in the bronchoalveolar lavage fluid to that of the serum, were 27.0 and 0.39, respectively. Our results suggest that 123I-IMP or its metabolites are transported through alveolo-capillary barrier and taken up by free cells in the alveolar space after 123I-IMP has been bound to nonspecific receptor sites in the endothelial cell in the capillary lumen.     

123I-IMP accumulation in the lung with bronchial asthma--early uptake and delayed washout

123I-IMP is taken up by the pulmonary capillary endothelial cells during the first pass through the lung, and is slowly released from them. To look up the factors which influence on the prolonged 123I-IMP retention in the diseased lung, we examined the correlation between the 123I-IMP uptake during the first pass and the 123I-IMP retention. Patients with bronchial asthma had no abnormal finding in the chest X-ray photograph. However 123I-IMP release from their lungs was delayed. Some patients show a tendency that 123I-IMP uptake during the first pass was uneven, which suggested the change in amine uptake function of endothelial cells. However their correlation coefficients between the uptake during the first pass and the prolonged retention were very small. It was considered that the prolonged 123I-IMP retention in the diseased lung was not explained only by the change in uptake function of pulmonary capillary endothelial cell.     

A case of primary malignant lymphoma of the brain with high uptake of 123I-IMP

Summary In general the ¹²³I-IMP SPECT image of a brain tumor is visualized as a defect. Tumor case with high IMP uptake have been rarely reported. We encountered a case of primary malignant lymphoma of the brain with high IMP uptake on both early and late scans corresponding to the CT lesions. Previously reported positive cases seemed to be confined to the early scan. For the present the exact behaviour of IMP is incompletely understood, but the mechanism of high uptake has been accounted for by increased extraction and increased amine receptors at the tumor sites. We need further information to establish whether these SPECT findings were specific for primary malignant lymphoma of the brain.     

123I-IMP clearance of the lung with diffuse lung disease

N-isopropyl-I-123-p-iodoamphetamine (123I-IMP) is taken up by the capillary endothelial cells during the first pulmonary pass and is released from the lung. To evaluate the effect of the 123I-IMP retention on diffuse lung disease, we studied prolonged 123I-IMP clearance from lung in 5 non-smoking control volunteers and 15 patients with various diffuse lung diseases. The time-activity curve for 60 min after the injection of 111 MBq of 123I-IMP was described as follows: C(t) = A1e-k1t + A2e-k1t (A1, A2: intercepts; K1, K2: slopes of the exponential components). 123I-IMP clearance was delayed in the patient group and K2 was significantly lower. There was a significant correlation between K2 and Ga-computer activity index on the 67Ga scintigraphy in the patient group. K2 was also correlated with %Dlco on the pulmonary function test. Our study suggests that the delayed clearance and retention of 123I-IMP in the diseased lung are influenced by the pathological activity in the lung lesion.     

Prolonged lung retention of123I-IMP in pulmonary fibrosis

We compared radiographic findings and the retention of N-isopropyl- p[123I]-iodoamphetamine (123I-IMP) in 23 patients with pulmonary fibrosis. During the 30 minutes following a rapid injection of 55.5 MBq of 123I-IMP into the antecubital vein, the image of regional activity was stored. After this, 185 MBq of 99mTc-MAA was injected and its image was stored to determine the region of interest. The half time (T1/2) of 123I-IMP release from the lung was calculated in each pixel between 10 and 25 minutes after the injection. Chest roentgenograms were taken, and the lung field was divided into 6 portions (right upper, middle and lower, and left upper, middle and lower). A quantitative score was assigned to the radiographic finding (X-ray score). The T1/2 values in the above patients were longer than the T1/2 values in normal subjects. Prolonged T1/2 values were observed in the lung fields which had high X-ray scores. The X-ray scores and the T1/2 values in corresponding areas had a positive relation.     

Prolonged lung retention of 123I-IMP in pulmonary disease

The accumulation of venously injected 123I-IMP in the lung was studied. Between 30 and 50 min after the injection of the 1.5 mCi 123I-IMP, the concentration of 123I-IMP in the broncho-alveolar lavage fluid were much higher than in the blood. It was considered that 123I-IMP was transported into the alveolar spaces and was absorbed by the alveolar cells. The half time (T1/2) of the 123I-IMP release from the lung between 10 and 25 min immediately after the injection was calculated. In normal subjects the T1/2 ranged between 25 and 44 min and was prolonged in subjects with pulmonary fibrosis, sarcoidosis, and allergic alveolitis. It was considered that the retention of 123I-IMP was related not only to the endothelial cells, but also to the alveolar cells. It was considered that the analysis of the lung release of 123I-IMP forms a new lung dysfunction index.     

Prolonged lung retention of 123I-IMP in pulmonary disease

The accumulation of venously injected ¹²³I-IMP in the lung was studied. Between 30 and 50 min after the injection of the 1.5 mCi ¹²³I-IMP, the concentration of ¹²³I-IMP in the broncho-alveolar lavage fluid were much higher than in the blood. It was considered that ¹²³I-IMP was transported into the alveolar spaces and was absorbed by the alveolar cells. The half time (T _1/2) of the ¹²³I-IMP release from the lung between 10 and 25 min immediately after the injection was calculated. In normal subjects the T _1/2 ranged between 25 and 44 min and was prolonged in subjects with pulmonary fibrosis, sarcoidosis, and allergic alveolitis. It was considered that the retention of ¹²³I-IMP was related not only to the endothelial cells, but also to the alveolar cells. It was considered that the analysis of the lung release of ¹²³I-IMP forms a new lung dysfunction index.     

Experimental study on 123I-IMP kinetics in irradiated lung of rabbit]

Radiation-induced alteration of intra-pulmonary kinetics of 123I-IMP was investigated in 11 rabbits received a 50 Gy dose of radiation to the hemithorax. In all of these rabbits examined during 3-17 weeks following the irradiation, an abnormal accumulation was seen in the irradiated lung on the delayed image obtained 60 minutes after the injection of 123I-IMP. The time-activity curves in the irradiated lung following the injection had shallower downslopes of both the initial fast phase and the following slow phase than those of non-irradiated lung, and finally 123I-IMP uptake of the irradiated lung exceeded that of the normal lung. Chest radiographies all of 11 rabbits showed no abnormal shadow and histological studies in 6 of them revealed a relatively slight change or injury of the irradiated lung during 3-17 weeks. These results indicate that this agent may be useful for detecting and assessing relatively early and slight lung injury induced by irradiation.     

Differentiation of infiltrates between lung cancer and noncancerous lung disease by 123I-IMP lung imaging

Lung imaging with N-isopropyl-p-123I-iodoamphetamine (123I-IMP) was performed to estimate the pulmonary lesion imaging findings in 3 patients with bronchogenic carcinoma (2: bronchioloalveolar carcinoma and 1: adenocarcinoma) and 18 with noncancerous lung diseases (10: bacterial pneumonia, 1: viral pneumonia, 1: aspiration pneumonia, 1: radiation pneumonitis, 4: pulmonary tuberculosis and 1: obstructive pneumonitis due to an endobronchial lipoma) at 30 min and 4 hr after i.v. injection of 111 MBq of 123I-IMP. These patients all exhibited infiltrates only in the chest radiograms. Decreased uptake of 123I-IMP was observed in the cancerous infiltrating lesions in 3 patients with bronchogenic carcinoma at 30 min and 4 hr, while the uptake of 123I-IMP was normal or increased at 30 min and intense at 4 hr in all 18 noncancerous infiltrating lesions. Therefore 123I-IMP lung imaging can be used to differentiate bronchogenic carcinoma from noncancerous lung disease in patients who exhibit infiltrates only in the chest radiograms.     

SPECT images after intravenous injection of 99mTc-DTPA in lung tumors--comparison with delayed 123I-IMP lung scintigraphy

The aim of this study was to assess the efficacy of SPECT imaging of the thorax with 99mTc-DTPA, which accumulates at sites of increased capillary permeability and expanded extracellular space, by comparing it with delayed 123I-IMP lung scintigraphy. We have previously reported that increased uptake on delayed 123I-IMP lung scintigraphy was associated with atelectasis and inflammation. Thirteen patients with lung cancer (4 with atelectasis and 3 with pleurisy), one patient with malignant lymphoma complicated by pneumonia and pleurisy, and one patient with pneumonia were studied. 99mTc-DTPA scintigraphy was performed twice, 20-160 minutes and 2-4 hours after the intravenous administration of 370 MBq of 99mTc-DTPA. 123I-IMP scintigraphy was performed 24 hours after the intravenous injection of 111 MBq of 123I-IMP. SPECT images were obtained with both types of scintigraphy. 99mTc-DTPA scintigraphy was compared with 123I-IMP scintigraphy for its ability to detect atelectasis and pneumonia. All patients showed increased accumulation corresponding to the lesions on both 123I-IMP and 99mTc-DTPA scintigraphy. 123I-IMP scintigraphy showed a defect corresponding to the tumor with increased accumulation around the tumor, whereas 99mTc-DTPA scintigraphy showed accumulation corresponding to the tumor. Ten of 11 tumors showed accumulation of an intensity equal to that of the soft tissue of the chest wall on 20-60 min 99mTc-DTPA images. The 2-4 hr images showed that 99mTc-DTPA leaked from the periphery of the tumor toward its center. All the patients with pleurisy showed increased accumulation in effusion on 2-4 hr 99mTc-DTPA scintigraphy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Compartment analysis of 123I-IMP brain SPECT

To clarify the kinetics of N-isopropyl [123I]p-iodoamphetamine (IMP) in the brain, 2-compartment analysis was applied for brain SPECT with 57-minute dynamic scan in 9 subjects. The model consisted of blood component and brain tissue component. Two transfer rate constants were defined; k1 showed the rate from the blood to the brain tissue, and k2 was that of back diffusion. The late scan was performed 210 minutes after the tracer injection. Suitable k values best fitting to the dynamic data were determined for all regions of interest. Predicted regional cerebral activity at 210 minutes using 57-minute dynamic data was well agreed with measured activity. These showed the kinetics of IMP in the brain was well described by the 2-compartment model. The partition coefficient (k1/k2 ratio) was as large as about 35, and almost constant in the various brain structures including hypoperfused areas. These findings indicated that the initial IMP images reflected the reasonable CBF distribution, which gave relatively reliable CBF values even if using microsphere model.     

123I-IMP per-rectal portal scintigraphy in a patent ductus venosus: a case report

Portosystemic shunt is most frequent in portal hypertension associated with hepatic cirrhosis, meanwhile there are uncommon cases which have congenital portosystemic shunt. Recently we have encountered a patient with ductus venosus definitely diagnosed by angiography. In this patient, we performed a portal scintigraphy with 123I-IMP per-rectal administration in order to evaluate the portosystemic circulation. At the early phase of the study, the scintigraphy showed only the pulmonary uptake of 123I-IMP, and the liver was not revealed. Such findings in congenital anomalous cases of portosystemic shunt without hepatic parenchymal damage like this case can be similar to those in cirrhotic patients. In conclusion, this method was useful in evaluation of the portosystemic circulation, and helpful in determining therapeutic procedures for portosystemic circulation disorders.     

Usefulness of 123I-IMP SPECT in patients with epilepsy

N-isopropyl-p-[123I]iodoamphetamine(123I-IMP)SPECT and electroencephalography (EEG) were evaluated in 21 epileptic patients at interictal stage. The findings of 123I-IMP were compared with those of clinical symptoms and EEG. In 11 cases (85%) of 13 patients with the partial seizure, and 6 cases (75%) of 8 patients with the generalized seizure had focal decreased perfusion of 123I-IMP. The mean number of focal decreased perfusion areas were 3.2 locations 1 case. There were no cases that was observed focal increased perfusion. Focal decreased perfusion area of 123I-IMP SPECT findings agreed with the focuses those were inferred from clinical findings in 8 cases (62%) out of 13 patients with the partial seizure, did not agree in 3 cases (23%) and did not detected in 2 cases (15%). Overall abnormality of 123I-IMP SPECT was observed in 17 cases (81%) out of 21 patients, on the other hand abnormality of EEG was observed in 12 cases (57%). 123I-IMP SPECT may provide useful information for evaluating foci in patients with epilepsy.     

Clinical and experimental studies on the mechanism of abnormal accumulation in lung scanning with 123I-IMP.

To investigate the intrapulmonary kinetics of N-isopropyl-p-I-123-iodoamphetamine (123I-IMP), lung scanning with 123I-IMP was performed in patients with various lung disorders. Compared with the normal lung field, abnormal accumulation of 123I-IMP was detected in all patients in delayed imaging performed 24 h after 123I-IMP injection. These sites were within areas of absent or reduced perfusion observed by pulmonary perfusion scanning using 99Tcm-macroaggregated albumin (99Tcm-MAA). A similar phenomenon was seen in additional experiments in rabbits with regional pulmonary arterial hypoperfusion resulting from a balloon catheter-induced bronchial occlusion. 123I-IMP accumulation in areas where 99Tcm-MAA images are absent or decreased may be explained by the ability of 123I-IMP to penetrate significantly narrowed microvascular beds with reduced perfusion. Our clinical and experimental results indicate that pulmonary arterial perfusion, particularly hypoperfusion, influence the pulmonary kinetics of 123I-IMP. This compound is a potentially useful non-particulate agent for the assessment of pulmonary arterial perfusion.     

A case of bone metastases from carcinoma of the lung demonstrating increased uptake of 99mTc-ECD

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.     

Remote effects in cerebral infarction--123I-IMP SPECT study

We studied the remote effects in 29 patients with middle cerebral artery territory infarction by using single photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]iodoamphetamine. SPECT demonstrated a reduction in blood flow in the cerebellar hemisphere contralateral to the cerebral infarct, the cortex ipsilateral to the subcortical infarct, the visual cortex distal to the optic radiation lesion, and the thalamus ipsilateral to the cortical infarct. In addition to transient neuronal depression identified with diaschisis, our results indicated that persistent phenomena were apparently involved in these remote effects. The degenerative processes might be related to irreversible effects in remote areas. Clinical symptoms corresponding to the areas of hypoperfusion remote from infarcted lesions were not necessarily present.     

Visualization of functional improvement by 123I-IMP lung SPET after thromboendarterectomy for chronic pulmonary embolism

We report on six patients with chronic pulmonary embolism who underwent 123I-IMP and 99Tcm-MAA lung SPET before and after thromboendarterectomy. 123I-IMP lung SPET can assess the viability of lung parenchyma, because it is a non-particulate agent that accumulates in the endothelial membranes of pulmonary capillaries. Chronic pulmonary thromboembolism accompanied by pulmonary hypertension has a poor prognosis that may be improved only by thromboendarterectomy. We compared 123I-IMP and 99Tcm-MAA lung SPET in terms of functional improvement after such surgery. After thromboendarterectomy, all six patients were functionally improved, according to the criteria of the New York Heart Association. The pre- and post-surgery percentage of vascular obstruction did not differ significantly with 99Tcm-MAA lung SPET (44.8 +/- 11.2% and 32.5 +/- 15.6% pre- and post-surgery, respectively). In contrast, 123I-IMP lung SPET revealed a significant pre- versus post-surgery difference (15.5 +/- 9.5% and 3.3 +/- 5.9% pre- and post-surgery, respectively). 123I-IMP lung SPET could be useful for evaluating thromboendarterectomy because pulmonary parenchymal viability owing to arterial microvasculature can be estimated.