Diagnosis of renovascular hypertension with captopril renal scintigraphy in a patient with a solitary kidney.

A patient with a solitary kidney due to renal agenesis and contralateral kidney perfusion impairment due to renal artery stenosis was successfully treated with percutaneous transluminal renal angioplasty. Preintervention diagnostic work-up included captopril renal scintigraphy, which was suggestive of high probability of renovascular hypertension. Scintigraphic assessment 2 mo after angioplasty failed to show any abnormality after captopril administration, a finding in line with blood pressure beneficial response to renal artery revascularization. A 12-mo follow-up confirmed cure of hypertension.

Detecting hibernated myocardium with SPECT and thallium-glucose-insulin infusion.

UNLABELLED: Because thallium kinetics, like potassium kinetics, may be affected by serum insulin levels, we performed two pilot studies to identify severely ischemic myocardium using different protocols based on the infusion of a thallium, insulin, potassium and glucose solution. Results were compared with those obtained with two currently used protocols based on rest injection or reinjection of 201Tl. METHODS: In the first study (Protocol 1) of 15 men with a previous large myocardial infarction, perfusion was evaluated by SPECT in 20 segments after a 30-min infusion of 201Tl (111 MBq), insulin (5 U) and potassium (10 mEq) in 10% glucose solution (250 ml). Imaging was repeated 30 min later and the results were compared with those obtained from stress and 3-hr reinjection images. In the second study (Protocol 2), 15 patients were evaluated randomly at rest and 3 hr later (rest-redistribution). On a separate day, the patients were then re-evaluated after infusion of 201Tl (111 MBq), potassium (10 mEq) and insulin (5 U) in 5% glucose (250 ml); images were obtained 90 and 180 min postinjection. RESULTS: In Protocol 1, radiotracer activity in segments with no uptake during stress was detected in 35% with the reinjection technique and 58% with the insulin solution protocol. In Protocol 2, 31% of segments revealed thallium activity after insulin infusion but not at rest or rest-redistribution. Serum measurements showed high insulin levels (444 +/- 138 in Protocol 1, 125 +/- 33 mU/ml in Protocol 2), although glucose levels were not significantly altered (149 +/- 32 versus 71 +/- 20 mg/dl, respectively). Potassemia was not affected and the patients tolerated the tests satisfactorily. CONCLUSION: These results confirm that continuous infusion of 201Tl with a low dose of insulin in a glucose/potassium chloride solution is safe and may enhance cellular uptake of the radiotracer in severe ischemic regions, thereby improving viable myocardium detection.

Use of technetium-99m-MAG3 for renal scintigraphy after angiotensin-converting enzyme inhibition.

Technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) was tested in 82 hypertensive patients submitted to renal scintigraphy 1 hr after oral premedication with 50 mg of Captopril. Baseline studies were obtained only for those patients showing abnormal findings in the provocative study. All patients underwent renal arteriography. Sensitivity and specificity for the detection of renal artery stenosis (RAS) greater than 50% were 89% and 91%, respectively. After Captopril administration, tracer parenchymal transit time increased significantly in ischemic kidneys (334 +/- 93 sec in baseline conditions versus 468 +/- 96 sec after Captopril, p less than 0.001) but not in kidneys with no RAS or RAS less than 50% (243 +/- 46 sec versus 271 +/- 95 sec, p = ns). False-positive responses were mostly bilateral and associated with a marked decrease in blood pressure. Technetium-99m-MAG3 is an effective compound for detecting RAS greater than or equal to 50% with Captopril renal scintigraphy. Performing the provocative test as a first step considerably reduced the number of scintigraphic studies required.

Retrograde colonic spread of a new mesalazine rectal enema in patients with distal ulcerative colitis.

BACKGROUND: Rectal treatment with mesalazine enemas is the first-line therapy for distal ulcerative colitis. In order to improve the benefits of rectal therapy, a new 60 mL 5-ASA rectal gel enema preparation has been developed using a device which excludes direct contact of the inert propellant gas with the active drug. The purpose of the present study was to assess by scintigraphy the colonic distribution of this new mesalazine rectal gel enema. METHODS: Twelve patients with active ulcerative colitis were administered 4 g of the mesalazine rectal enema labelled with 100 MBq technetium sulphur colloid (99mTc-SC). Anterior scans of the abdomen were acquired at intervals for 4 h. Scans were analysed to evaluate the extent of retrograde flow and homogeneity of distribution of the radiolabelled enema in the rectum, sigmoid, descending and transverse colon. In addition, plasma levels of 5-ASA and Ac-5-ASA were measured for 6 h. RESULTS: All patients retained the entire rectal gel throughout the course of the study without reporting adverse events. In 11 out of 12 patients (92%) the gel had spread homogeneously beyond the sigmoid colon and had reached the upper limit of disease in all cases. The maximum spread (splenic flexure) was observed in 6 out of 12 patients (50%) within the first 2 h. The systemic absorption of mesalazine and its metabolite Ac-5-ASA was low. CONCLUSIONS: The new mesalazine enema represents an adequate alternative and a further technological improvement in the topical treatment of distal ulcerative colitis.

Gastric retention of sucralfate gel and suspension in upper gastrointestinal diseases.

This study was designed to compare by scintigraphy the gastric retention of a new dosage form of sucralfate as gel (Gastrogel) with that of sucralfate suspension in 25 patients with upper gastrointestinal symptoms referred for routine endoscopy. After endoscopy 4 subgroups were defined: macroscopically normal mucosa (n = 7), antral gastritis and/or erosions (n = 6), gastric ulcer (n = 6) and duodenal ulcer (n = 6). Each patient received either sucralfate gel or sucralfate suspension in equivalent doses (5 ml containing 1 g sucralfate). Both formulations were labelled with 111 MBq 99mTc-DTPA before administration. The mean value of t1/2 in the total group was significantly longer when patients were taking sucralfate gel (61.6 min) compared to sucralfate suspension (33.8 min) (P < 0.001). The mean values of t1/2 were significantly longer for sucralfate gel compared to sucralfate suspension also among the subgroups (macroscopically normal P < 0.02, antral gastritis P < 0.05, gastric ulcer P < 0.02 and duodenal ulcer P < 0.05). After 2 and 3 hours, the percentage residual activity in the gastric area was significantly higher following administration of sucralfate gel compared to sucralfate suspension. This study has shown that, compared to sucralfate suspension, sucralfate gel persists longer in the stomach of patients with gastritis and peptic ulcer.

Reproducibility of a solid and of a liquid caloric meal for gastric emptying studies.

Simple meals are required for routine scintigraphic gastric emptying studies. We evaluated the reproducibility of a caloric liquid meal (520 kcal) compared to that of a solid meal (638 kcal) in 8 and 11 healthy volunteers, respectively. Gastric emptying rates and half-times were similar in two tests using the same meal, while the methods used to express lag times were not highly reproducible. The emptying rates and half-times of the liquid meal were delayed after the intake of bellafoline. In conclusion, this study demonstrates that: (a) gastric emptying rates and half-times are reproducible parameters for the expression of scintigraphic gastric emptying studies; (b) mathematical methods to express lag times are not highly reproducible; (c) a 500 kcal liquid meal is sensitive to the effects of bellafoline, a drug able to delay gastric emptying. Further clinical evaluation is required to test its applicability in routine studies.

Evaluation of hypertensive patients with a solitary kidney using captopril renal scintigraphy with 99Tcm-MAG3.

The study aimed to evaluate the safety and reliability of captopril renal scintigraphy (CRS) for diagnosing functionally significant renal artery stenosis (RAS) in hypertensive patients with a solitary kidney. Radionuclide studies were carried out using 100 MBq 99Tcm-mercaptoacetyl triglycine (MAG3), 1 h after administration of 50 mg captopril, and repeated in baseline condition when abnormalities were observed in the provocative study. Scintigraphic diagnosis of RAS was based on analysis of captopril-induced changes of the radiorenographs. Overall, 12 patients with a solitary kidney were investigated, and scintigraphic results compared to angiographic findings. All five patients with positive CRS showed an RAS > 50%, whereas only one of the seven patients with negative CRS was affected by RAS. A significant fall in mean arterial pressure was recorded after captopril administration (123 +/- 12 mm Hg before versus 108 +/- 11 after), but no serious side effects were observed. Our results demonstrate that captopril-induced modifications of the renogram could effectively be used to diagnose the presence of RAS. Captopril renal scintigraphy may therefore be suggested as a reliable and safe noninvasive approach to evaluate hypertensive patients with a solitary kidney.

Biomarker responses at different levels of biological organisation in crabs (Carcinus aestuarii) experimentally exposed to benzo(alpha)pyrene.

The aim of this study was to validate a multi-trial biomarker approach for the evaluation of toxicological risk due to benzo(alpha)pyrene. Carcinus aestuarii, exposed to increasing concentrations of B(alpha)P in the water, was used as the bioindicator organism. A set of biomarkers were tested in order to: identify biological materials for biomarker and residue analysis; determine a group of sensitive techniques for the assessment of PAH contamination; investigate correlation between responses at different levels of biological organisation. The results underlined that BPMO activities in hepatopancreas and gills were a good biomarker of exposure to PAH-type compounds. B esterases activities in hemolymph and porphyrin patterns in excreta could be proposed as a non-destructive approach for evaluating chemical exposure in this species.

Occult colon cancer in a patient with an unexplained episode of pulmonary embolism.

The association between venous thromboembolism and cancer has been widely documented and the main factor responsible for cancer-induced venous thromboembolism is considered mostly linked to a hypercoagulation state induced by the cancer itself. There is no consensus on investigative strategies for occult cancer in a patient with a thrombophilic condition. We report a patient who manifested an isolated episode of pulmonary embolism without specific evident sources of venous thromboembolism. The routine clinical and laboratory work-up to detect an occult cancer did not reveal any malignancy. A history of duodenal ulcer in association with a recent slight alteration in bowel habits led us to perform an esophagogastroduodenoscopy which was negative for malignancy, and a barium enema followed by colonoscopy, which revealed the presence of a tumor limited to the large intestine. An unexplained clinically evident hypercoagulation state, even in the presence of mild clinical symptoms, needs more thorough diagnostic strategies when simple methods of screening for occult cancer are negative.

Evaluation of lung clearance of inhaled pertechnegas.

Pertechnegas is a new ventilation agent produced by modifying the atmosphere of combustion of Technegas. Due to its rapid disappearance from the lungs, Pertechnegas has been suggested as useful in measuring pulmonary epithelial permeability. This study aimed to assess the reliability of ventilation scans with Pertechnegas to evaluate alveolar-capillary permeability. Six non-smokers with no evidence of pulmonary disease were investigated. Scintigraphic data were used to evaluate the site of Pertechnegas deposition (by assessing the Penetration Index [PI] of the gas), its clearance rate (by calculating the time to half-clearance [T1/2]) and its lung distribution (by means of a pixel-by-pixel analysis. PI measurements produced a mean value of 88.8 +/- 13.3% (range 69-117%). Time activity curves showed a fast clearance in all cases (mean T1/2 = 10.7 +/- 2.1 min, range 8.1-14.3 min). Comparison of statistical indices of uniform deposition (skewness and kurtosis) indicated satisfactory homogeneity of Pertechnegas distribution throughout the lungs. These data show that after inhalation Pertechnegas has a peripheral deposition and a homogeneous distribution in the lungs and is rapidly cleared through the alveolar-capillary barrier. In conclusion Pertechnegas can be recommended as a potential radiopharmaceutical for studying the pulmonary epithelial barrier.