The perinatal effects of maternal caffeine intake on fetal and neonatal brain levels of testosterone, estradiol, and dihydrotestosterone in rats.

Testosterone, estradiol, and dihydrotestosterone are the main sex steroid hormones responsible for the organization and sexual differentiation of brain structures during early development. The hypothalamo-pituitary-adrenocortical axis, adrenal cells, and gonads play a key role in the production of sex steroids and express adenosine receptors. Caffeine is a non-selective adenosine antagonist; therefore, it can modulate metabolic pathways in these tissues. Besides, the proportion of pregnant women that consume caffeine is ∼60%. That is why the relationship between maternal caffeine consumption and fetal development is important. Therefore, we aimed to investigate this modulatory effect of maternal caffeine consumption on sex steroids in the fetal and neonatal brain tissues. Pregnant rats were treated with a low (0.3 g/L) or high (0.8 g/L) dose of caffeine in their drinking water during pregnancy and lactation. The testosterone, estradiol, and dihydrotestosterone levels in the frontal cortex and hypothalamus were measured using radioimmunoassay at embryonic day 19 (E19), birth (PN0), and postnatal day 4 (PN4). The administration of low-dose caffeine increased the body weight in PN4 male and female rats and anogenital index in PN4 males. The administration of high-dose caffeine decreased the adrenal weight in E19 male rats and increased testosterone levels in the frontal cortex of E19 female rats and the hypothalamus of PN0 male rats. Maternal caffeine intake during pregnancy affects sex steroid levels in the frontal cortex and hypothalamus of the offspring. This concentration changes of the sex steroids in the brain may influence behavioral and neuroendocrine functions at some point in adult life.

Increased FDG uptake in pulmonary epitheloid hemangioendothelioma.

A 40 year-old female was examined for complaints of left arm pain and restriction of movement in the left upper extremity for 3 months. Chest X-ray showed a mass in the left upper lung and the patient was evaluated with computed tomography that confirmed the significant mass in the left paratracheal region and also showed small nodules in both of the lungs. A whole-body FDG-PET scan was performed for the suspicion of malignancy. FDG-PET indicated high FDG accumulation in the lung lesions mainly in the left paratracheal region. FDG-PET findings were highly suspicious of malignancy so the patient had thoracoscopic biopsy of the lesion. The histological findings and immunohistochemistry tests were consistent with pulmonary epitheloid hemangioendothelioma (PEH). Epitheloid hemangioendothelioma (EH) is a systemic name that represents a rare type of malignant tumor of vascular endothelial origin, which can arise in bone, liver, soft-tissue, or lung. PEH is currently known as the lung form of EH. Consequently, our patient had resection of the left paratracheal mass. This report presents a rare case of histologically confirmed PEH, which showed increased FDG accumulation on FDG-PET study. PEH should be added to the other causes of increased FDG uptake.

Increased FDG uptake in pulmonary epitheloid hemangioendothelioma

Examinamos a una mujer de 40 años de edad, que llevaba tres meses quejándose de dolor en su brazo izquierdo y de restricción del movimiento en la parte superior del mismo. La radiografía de tórax mostró una masa en la parte superior del pulmón izquierdo, por lo que la paciente fue evaluada con una tomografía computarizada que confirmó una masa significativa en la región paratraqueal izquierda, con apreciación de pequeños nódulos en ambos pulmones. Se realizó un estudio de tomografía por emisión de positrones con fluordeoxiglucosa (FDG-PET) del cuerpo entero por sospecha de malignidad. El estudio indicó una alta acumulación de FDG en las lesiones pulmonares, y principalmente en la región paratraqueal izquierda. Los hallazgos del FDG-PET fueron altamente sospechosos de malignidad, por lo que se realizó una biopsia toracoscópica de la lesión. Los hallazgos histológicos y las pruebas histoinmunoquímicas fueron compatibles con el hemangioendotelioma epiteloide pulmonar (HEP). El hemangioendotelioma epiteliode (EH) es una denominación sistémica que representa un tipo raro de tumor maligno de origen vascular epiteloide que puede aparecer en el hueso, hígado, tejido blando o pulmón. El HEP es conocido actualmente como la forma EH en el pulmón. Por consiguiente, nuestra paciente tuvo una resección de la masa paratraqueal izquierda. Este trabajo presenta un caso raro de HEP confirmado histológicamente, el cual muestra una acumulación incrementada de FDG en el estudio FDG-PET. El HEP debería añadirse a las otras causas de incremento de captación de FDG

A 40 year-old female was examinated for complaints of left arm pain and restriction of movement in the left upper extremity for 3 months. Chest X-ray showed a mass in the left upper lung and the patient was evaluated with computed tomography that confirmed the significant mass in the left paratracheal region and also showed small nodules in both of the lungs. A whole-body FDG-PET scan was performed for the suspicion of malignancy. FDG-PET indicated high FDG accumulation in the lung lesions mainly in the left paratracheal region. FDG-PET findings were highly suspicious of malignancy so the patient had thoracoscopic biopsy of the lesion. The histological findings and imunohistochemistry tests were consistent with pulmonary epitheloid hemangioendothelioma (PEH). Epitheloid hemangioendothelioma (EH) is a systemic name that represents a rare type of malignant tumor of vascular endothelial origin, which can arise in bone, liver, soft-tissue, or lung. PEH is currently known as the lung form of EH. Consequently, our patient had resection of the left paratracheal mass. This report presents a rare case of histologically confirmed PEH, which showed increased FDG accumulation on FDG-PET study. PEH should be added to the other causes of increased FDG uptake

Detection of inflammatory lymph nodes in rabbits by 99mTc-HIG lymphoscintigraphy.

Tc-Human immunoglobulin G ( Tc-HIG) is a well-known radiopharmaceutical for the evaluation of inflammatory lesions. Recently, it has been demonstrated as a new agent for the visualization of the lymphatic system by our group. Our aim was to investigate the feasibility of detection of inflammatory lymph nodes by Tc-HIG lymphoscintigraphy. Ten adult New Zealand rabbits were used as group A. In a baseline study, 37 MBq Tc-HIG (0.1 ml) was injected into both hind legs of the rabbits, and sequential posterior gamma imaging with the rabbits lying prone was performed at 5, 15, 30, 60, 90 and 120 min using a single-headed gamma camera (Toshiba GCA G01 E). One week later, microorganisms ( ) were injected in a volume of 0.1 ml intradermally into the web space between the second and third toes in the bilateral hind legs of each rabbit in order to obtain inflammation in the popliteal lymph nodes. After 4 days, 37 MBq Tc-HIG (0.1 ml) was injected into the hind legs of the rabbits bilaterally, and sequential posterior gamma imaging was performed as described above (second study). Another group of 10 adult New Zealand rabbits (group B) was injected with the same microorganisms in the right hind legs only. After 4 days, scintigraphic imaging was carried out in the same way as described above (third study). Regions of interest were drawn over the injection sites and popliteal lymph nodes on each image for semiquantitative analysis. Count rates for each were calculated and a decay correction was applied. Time-activity curves were generated to show the percentage retention of radioactivity in each region. After the scintigraphic study, some of the group B rabbits were killed by intravenous injection of pentobarbitone (100-150 mg.kg, and both left and right lymph nodes were removed for microscopic examination. On the scintigrams, lymphatic channels and popliteal lymph nodes were visualized within 15 min. In the second study, bilateral popliteal lymph nodes were visualized more clearly than in the baseline study. The right popliteal lymph nodes of the rabbits were more clearly visualized in the third study. Semiquantitative analysis showed a higher percentage uptake of radioactivity in the right compared to the left popliteal lymph nodes in group B rabbits. Microscopic examination of the tissue sections demonstrated inflammation in the right lymph nodes of group B rabbits. In this preliminary study, it was found that Tc-HIG is a new promising agent for the demonstration and evaluation of inflammatory lymph nodes.

Tc-99m-DTPA captopril renography in the detection of renovascular hypertension due to renal polar artery stenosis.

A 24-year-old man whose clinical features were suggestive of renovascular hypertension was referred for captopril renal scintigraphy. Captopril renal scintigraphy was positive for renovascular hypertension only when the left kidney was analyzed in 2 separate regions. Angiography confirmed severe stenosis (90%) in the upper branch of the left renal artery.

Tc-99m DTPA acetylsalicylic acid (aspirin) renography in the detection of renovascular hypertension.

PURPOSE: Prostaglandins play important roles in renal physiology and in the development of renovascular hypertension. In a recent study, inhibition of renal prostaglandin synthesis was found to be useful for detecting renovascular hypertension using renal scintigraphy. In the current study, the authors evaluated the role of aspirin (an inhibitor of prostaglandin synthesis) and compared it with Tc-99m DTPA captopril renal scintigraphy (CS). MATERIALS AND METHODS: Twenty-five patients were examined with Tc-99m DTPA in a three-step manner: a baseline study, CS, and aspirin scintigraphy (AS). Each scintigraphic study was interpreted visually and according to the renogram curve patterns. Semiquantitative parameters (Tmax, renal indices [%], 20-minute/max count ratio, glomerular filtration rate) were also calculated. Plasma renin activity was determined for each study. The blood pressures of all patients were measured during AS. All patients had a contrast-enhanced angiogram that was used as the reference test. RESULTS: Three groups of patients were observed based on the scintigraphic and angiographic results. In each group, no difference was observed in blood pressure after aspirin administration. In group 1, seven patients had normal angiographic and scintigraphic results. In group 2, eight patients had angiographically confirmed renal artery stenosis (RAS). In 6 patients (mean, 47% RAS), both AS and CS were negative for RVH. In the remaining two patients with RAS (mean, 83% stenosis), the kidneys were atrophic on the stenotic side, and thus the kidneys did not respond to the interventions. No difference was observed in plasma renin activity in groups 1 and 2. Group 3 included 10 patients who had angiographically confirmed RAS (mean, 86%). In 9 patients, both CS and AS were positive for RVH. In the remaining one patient, scintigraphic results were falsely negative. Statistical analyses performed for semiquantitative parameters did not reveal any significant difference in this group, although there was a tendency toward prolonged Tmax values after captopril and aspirin administration. In four cases, unexpected elevation of plasma renin activity was observed in group 3. CONCLUSIONS: These data indicate that AS with Tc-99m DTPA is an alternative for CS. It has the advantage of having no effect on blood pressure and does not require that angiotensin-converting enzyme inhibitors be discontinued. Although in this study 9 of 10 patients had correct diagnoses of RAS, further studies, especially using tubular agents with the calculation of parenchymal transit time, might provide valuable information in this patient group. An ongoing study is being performed in the authors' institute.

Evaluation of 99mTc labelled poly lactic acid microspheres for diagnostic radioembolization.

Radioembolization is used in diagnostic imaging of the lungs and for radioembolization therapy of hepatic tumours. Presently, 99mTc labelled macroaggregates or microspheres of human serum albumin (HAM) are used for this purpose. Poly lactic acid (PLA) is biodegradable, like HAM, and, unlike HAM, is not a blood product. The aim of the present study was to evaluate the uptake and biodegradation of PLA microspheres in lungs. PLA (MW = 48720 Da) microspheres of 1.0-100 microm (mean = 39.5 microm) in diameter were prepared by solvent evaporation from methylene chloride. They were labelled with 99mTc by stannous chloride reduction at pH 3, with an efficiency of 98% and a stability of 96% at 24 h. For biodistribution studies, 15 mice were i.v. injected with 20 microCi 99mTc-PLA microspheres in 0.1 ml and sacrificed at 15 min, 1, 3, 6 and 24 h (three at each time point). All the organs were removed, weighed and counted against a standard prepared from 1/100 dilution of the injected radioactivity. Some mice were similarly injected and sacrificed at 30 min, 15 and 30 days. The lungs were removed and frozen, and 10 microm sections were obtained, stained with haemotoxylin and eosin and examined under a light microscope. Five rabbits were i.v. injected with 1 mCi of 99mTc-PLA microspheres. Scintigrams were obtained at various intervals up to 24 h. In mice, the lung uptake was significant at 30 min-1h post-injection. In rabbits, the lungs were the only organs visualized up to 24 h. Microscopic examination of tissue sections demonstrated slow biodegradation of PLA particles. In conclusion; (1) The high lung uptake obtained in mice and rabbits indicates the suitability of PLA microspheres for lung imaging, and (2) although the slow biodegradation rate might be a disadvantage in patients with lung disorders in diagnostic studies, it may be an advantage in therapeutic applications with radionuclides which have long physical half lives.

Comparison of Tc-99m EC and Tc-99m DTPA captopril scintigraphy to diagnose renal artery stenosis.

PURPOSE: Although, captopril scintigraphy is a well established method to detect renovascular hypertension, the optimal radiopharmaceutical for this test remains to be determined. Recently, Tc-99m ethylenedicysteine (Tc-99m EC) appeared as an alternative agent for captopril scintigraphy. The aim of this study was to compare the diagnostic accuracy of Tc-99m EC with Tc-99m DTPA, which is a well-established renal radiopharmaceutical for the captopril test. METHODS: Nineteen hypertensive patients who had various degrees of renal artery stenosis on angiography were included in the study. All patients had baseline and captopril Tc-99m EC and Tc-99m DTPA scintigraphy within a 1-week period. The results were compared with angiography and in eight patients with changes in blood pressure after revascularization. The images were interpreted without knowledge of the angiography and revascularization data as low, intermediate, or high probability for hemodynamically significant renal artery stenosis, which was defined as an area of stenosis exceeding 50%. RESULTS: Tc-99m EC and Tc-99m DTPA study results were in agreement in 16 of the 19 patients. In two patients with branch artery stenosis, Tc-99m EC was definitely superior to Tc-99m DTPA and correctly identified the probability of stenosis on scintigraphy. On kidney analysis, Tc-99m EC had a slightly greater diagnostic sensitivity compared with Tc-99m DTPA (79% vs. 68%; P > 0.05 by the chi-squared test) but equal specificity (93% for both agents). Both Tc-99m EC and Tc-99m DTPA showed the same accuracy in predicting the outcome after revascularization in all but one patient with branch artery stenosis, in whom Tc-99m EC accurately predicted a successful outcome of the intervention but Tc-99m DTPA did not. Tc-99m EC had better renal uptake in patients with decreased renal function and provided more dramatic evidence of renogram changes after captopril intervention, which resulted in more confident interpretation. CONCLUSIONS: There is no significant difference between Tc-99m EC and Tc-99m DTPA captopril scintigraphy for detecting renal artery stenosis. However, because of the better imaging characteristics and more confident interpretation provided by the dramatic changes in the degree of renogram abnormality after captopril intervention, Tc-99m EC captopril scintigraphy should be used, particularly in patients with decreased renal function or branch artery stenosis.

Prediction of response to revascularization in patients with renal artery stenosis by Tc-99m-ethylenedicysteine captopril scintigraphy.

The aim of the present study was to assess the predictive value of captopril scintigraphy with the new renal agent 99mTc-ethylenedicysteine (99mTc-EC) for post-interventional improvement in blood pressure. Twelve patients who had persistently high blood pressure with previous demonstration of various degrees of renal artery lesion on angiography were included into the study. Baseline and captopril scintigraphies were performed on the same day at 4 hour intervals after the injection of 74 and 296 MBq of 99mTc-EC, respectively. All patients had percutaneous transluminal angioplasty (PTA), and improvement in blood pressure was evaluated 3-6 months after the intervention. 99mTc-EC captopril scintigraphy successfully predicted a positive or negative outcome in 11 of 12 patients. In one patient with captopril induced renal function deterioration, scintigraphy failed to predict post-interventional response. Our preliminary findings showed that 99mTc-EC captopril scintigraphy can be used to determine patients who will benefit from revascularization.

Evaluation of 99Tcm-HIG as a lymphoscintigraphic agent in rabbits.

In this pilot study, 99Tcm-labelled human immunoglobulin G (99Tcm-HIG) was evaluated as a lymphoscintigraphic agent in five rabbits. It was injected intradermally into the web space of the hind legs of the rabbits (37 MBq/0.1 ml). Sequential scintigrams were obtained using a gamma camera for 120 min. The injection site and the hind legs were massaged post-injection. Blood samples were obtained at 5, 15, 30, 60, 90 and 120 min. Two of the rabbits were killed after 2 h. Their organs were weighed and tissue specimens were obtained, weighed and counted against a standard using a gamma counter. The lymph channels and the lymph nodes were well visualized on the scintigrams. The background activity was very low, making interpretation easier. About 30% of the injected dose migrated from the injection site by 2 h. The mean popliteal lymph node uptake was 5.71 +/- 4.62% per gram of tissue. The lymph node to other tissue concentration ratios were very high, ranging from 63:1 for the kidneys to 1099:1 for the heart. We conclude that 99Tcm-HIG is a promising new agent for the visualization of the lymphatic system due to its easy labelling procedure, the stability of the label, its widespread availability and good image quality. It may potentially be useful in detecting and evaluating inflammatory lymph nodes.

Paradoxical hypotension during dobutamine infusion for myocardial perfusion scintigraphy.

AIM: Dobutamine as a predominant beta-1 agonist increases heart rate and myocardial contractility and at sufficient high doses, it also increases systolic blood pressure. This study was undertaken to describe instances of paradoxical hypotension during dobutamine infusion for TI-201 myocardial perfusion SPECT study and the relationship between scintigraphic findings and hypotension occurred during dobutamine infusion. METHODS: In 201 consecutive patients unable to perform adequate exercise, dobutamine TI-201 myocardial SPECT was performed. Dobutamine was infused starting from 10 micrograms/kg/min increasing to 40 micrograms/kg/min. Paradoxical hypotension was defined as a decrease in systolic blood pressure > or = 20 mmHg compared with baseline study. RESULTS: Paradoxical hypotension was observed in 40 patients (Group A) out of 201 (19.9%) while no significant change in systolic blood pressure was detected in the remaining 161 patients (Group B). Mean maximum fall in systolic blood pressure was 39 +/- 18 mmHg (range: 20-90). In 33 of 40 patients (83%) with paradoxical hypotension, scintigraphy was normal compared to 131 (81%) of the remaining 161 patients. In patients of Group A, angiography, echocardiography and tilt table tests were performed in 13, 11 and 6 patients respectively. Nine of 13 angiographic evaluations (69%), 10 of 11 echocardiographic evaluations (91%), all of the tilt table tests were normal. Additionally, all of the patients of Group A were clinically followed up at least 6 months after the myocardial perfusion scintigraphy. None of the patients had a cardiac event except one patient during the follow-up period. CONCLUSION: Paradoxical hypotension during dobutamine infusion for myocardial scintigraphy is not an uncommon finding and up to 19.9% patients may develop such hypotension. To maximize test safety, precautions should be taken during dobutamine myocardial stress test, since remarkable decrease in systolic blood pressure may occur. Unlike hypotension occurring with exercise test, hypotension response to dobutamine is not always a marker for coronary artery disease.

Influence of the heterogeneity of P-glycoprotein expression on technetium-99m-MIBI uptake in breast cancer.

UNLABELLED: We prospectively studied a total of 30 patients with breast cancer to evaluate the relationship between the degree of accumulation of 99mTc-sestamibi (MIBI) and the heterogeneity of p-glycoprotein expression in tumor tissues. METHODS: Twenty patients during initial presentation and 10 patients during post-therapy evaluation underwent contemporaneous 99mTc-MIBI imaging and surgery or biopsy. Immunohistochemical studies were performed on multiple nonconsecutive sections of the same tumor using a p-glycoprotein-specific monoclonal antibody, JSB-1. Tumor-to-background (T/B) ratios were correlated with the level and heterogeneity of p-glycoprotein expression determined by immunohistochemical studies. RESULTS: The T/B ratios were lower for those tumors with strong p-glycoprotein expression (Group 1) than those with strong-to-weak expression (Group 2) or those with weak-to-no expression (Group 3) (1.32 +/- 0.19 and 1.85 +/- 0.56 and 2.86 +/- 1.06, respectively). There was statistically significant difference in T/B ratios between all 3 groups (p < 0.005). Although T/B ratios for Group 1 and Group 3 were clearly distinct from one another with no overlapping values, the values for Group 2 overlapped with those of Group 1 and Group 3. When we evaluated the entire patient group with excluding those with strong-to-weak expression, although the p value remained the same (p < 0.001), we obtained a stronger correlation between T/B ratios and p-glycoprotein expression (r = 0.808 versus 0.735). CONCLUSION: Due to the heterogeneous expression of p-glycoprotein, both immunohistochemistry and 99mTc-MIBI scintigraphy may yield confounding results by contrasting with one another if the presence or absence of p-glycoprotein is not extensively explored. Although our data confirmed that 99mTc-MIBI imaging is useful in the determination of the presence of multidrug resistance in patients with breast cancer, the issue of heterogeneous expression of the antigen should be further investigated when unexpected results are obtained.

Association of tumor washout rates and accumulation of technetium-99m-MIBI with expression of P-glycoprotein in lung cancer.

UNLABELLED: In a prospective study, we correlated the washout rates of 99mTc-sestamibi (MIBI) and the degree of MIBI accumulation with the expression of P-glycoprotein (Pgp) in tumor tissues in a total of 46 patients with lung cancer. METHODS: All patients underwent early (30 min) and delayed (3 hr) MIBI imaging and bronchoscopic biopsy before initiation of chemo- or radiotherapy. The interval between biopsy and imaging varied between 2 and 10 days. All patients had radiologically detectable tumors. Immunohistochemical studies were performed on paraffin sections using a monoclonal antibody, JSB-1, developed against the internal epitope of Pgp. Normal tissue and tumor washout rates and tumor-to-background ratios were correlated with the level of Pgp expression. RESULTS: There was an inverse correlation between tumor-to-background ratios and the density of Pgp (p = 0.001), whereas there was no appreciable correlation between tumor washout rates of MIBI and the level of Pgp expression (p = 0.414). CONCLUSION: The current data strongly suggest that, although the reduced ability for the tumors to accumulate MIBI correlates well with the increased levels of Pgp expression, tumor washout rates of MIBI do not correlate with the density of Pgp in tumor tissues. Our results also warrant additional research for correlating immunohistological and imaging findings with messenger RNA levels determined by polymerase chain reaction and flow cytometry.

Segmental ATN in a kidney with a single artery transplanted from living related donor.

A sequential 99mTc-MAG3 renogram of a 20-year-old male who received a kidney from a living related donor is presented. Pre-transplant angiography of the donor showed the kidney had a single renal artery with upper and lower branches. The transplantation procedure was uneventful, allowing rapid simultaneous perfusion to the entire kidney. The first scan performed 2 days after the transplantation was normal except for retention of the radiotracer at the upper pole of the kidney. The renal collecting system was normal and no signs of dilatation or obstruction were noticed on ultrasonographic examination. A follow-up scan done on the 5th day of transplantation showed almost complete evacuation of the parenchymal retention previously seen on the upper pole of the kidney. This unusual finding was consistent with segmental acute tubular necrosis (ATN) of the upper pole of the kidney and showed that ATN might involve only a portion of a kidney in spite of the existence of a single artery of the transplant.

The diagnosis of renovascular hypertension with technetium-99m-ethylenedicysteine captopril scintigraphy.

RATIONALE AND OBJECTIVES: The authors present preliminary findings on the diagnosis of renovascular hypertension with technetium-99m-ethylenedicysteine (99mTc-EC). METHODS: Thirty-nine patients referred to the nuclear medicine department with clinical evidence of renovascular hypertension were included in the study. Baseline and captopril scintigraphies were done on separate days after the injection of 185 MBq of 99mTc-EC. All patients had angiographic correlation and 9 patients were shown to have renal artery stenosis. RESULTS: Quantitative analysis of the data showed no significant changes of perfusion index (PI), split renal function (SRF), and effective renal plasma flow (ERPF) values between pre- and postcaptopril studies in patients with significant renal artery stenosis (P > 0.05). Baseline and postcaptopril values for PI, SRF, and ERPF were measured as 128 +/- 21 and 116 +/- 12 mL/minute, 47 +/- 1 and 50 +/- 2 mL/minute, and 250 +/- 18 and 231 +/- 20 mL/minute, respectively. However, time to maximum activity (Tmax), time to half maximum activity (T 1/2), time to two thirds of maximum activity (T 2/3), and residual cortical activity (RCA) values showed marked changes with a rising renogram curve (P < 0.05). Baseline and postcaptopril values for Tmax, T 1/2, T 2/3, and RCA were measured as 3.1 +/- 0.1 and 20.2 +/- 1 minute, 5.4 +/- 0.4 and 45.4 +/- 3.1 minutes, 3.1 +/- 0.2 and 33.7 +/- 4.1 minutes, and 27 +/- 4 and 215 +/- 34 minutes, respectively. All scintigraphic studies showed good correlation with angiography and no false-positive or false-negative results were observed. CONCLUSIONS: This preliminary study demonstrates that 99mTc-EC has good potential for the diagnosis of renovascular hypertension and that a single diagnostic criteria, specifically a rising renogram curve, seems adequate. However, the authors' initial results should be confirmed in a broader patient population.

Technetium-99m-ethylenedicysteine in the diagnosis and follow-up of renovascular hypertension.

Technetium-99m-ethylenedicysteine (99mTc-EC) captopril scintigraphy performed in a patient with severe hypertension revealed increased parenchymal retention in the left kidney, suggesting renal artery stenosis. After angiographic confirmation of renal artery stenosis, percutaneous transluminal angioplasty (PTA) was performed on the left renal artery. Captopril scintigraphy after PTA showed normal findings with no evidence of parenchymal retention, consistent with reversal to normal kidney functions. In light of this case of renal artery stenosis, it was concluded that 99mTc-EC can be used successfully as a potential renal agent in the diagnosis and follow-up of renovascular hypertension.