Liver perfusion scintigraphy prior to and after transjugular intrahepatic portosystemic shunts (TIPS) in patients with portal hypertension.

PURPOSE: This investigation was performed to compare the hemodynamic results of the transjugular intrahepatic portosystemic shunt, a new interventional treatment for portal hypertension, with those observed after the established surgical shunt interventions. METHODS: We examined 22 patients with portal hypertension due to liver cirrhosis before and after elective TIPS by liver perfusion scintigraphy. The relative portal perfusion was determined before and after the shunt procedure. Additionally, we measured the portal pressure gradient (PPG: portal-central venous pressure, mmHg). RESULTS: Prior to TIPS, the relative portal perfusion was significantly reduced to 22 +/- 9.1%. After the intervention we calculated values of 23.1 +/- 10.7% in the TIPS-group (p = 0.67; not significant). In spite of unchanged portal perfusion, the portal pressure was significantly (p < 0.001) reduced from 25.6 +/- 5.3 to 14.8 +/- 4 mm Hg. CONCLUSION: These results suggest that the reduction of portal hypertension by TIPS is effective. The portal perfusion is maintained by TIPS suggesting that liver perfusion is preserved to a higher degree.

Regional cerebral blood flow single-photon emission tomography with 99mTc-HMPAO and the acetazolamide test in the evaluation of vascular and Alzheimer's dementia.

The diagnostic potential of technetium-99m hexamethylpropylene amine oxime (HMPAO) following systemic administration of the cerebral vasodilator acetazolamide (acetazolamide test) was evaluated by regional cerebral blood flow (rCBF) single-photon emission tomography (SPET) in patients with Alzheimer's disease (AD) or vascular dementia (VD). An initial, high-resolution SPET study was performed with 99mTc-HMPAO, and after 2 days the patients were re-evaluated with 99mTc-HMPAO following systemic administration of acetazolamide. Reconstructed SPET slices were evaluated visually and semiquantitatively by a semi-automatic rCBF map method. When 99mTc-HMPAO alone was used, bilateral hypoperfusion was found in the temporal and/or parietal regions in 33% (6/18) of the VD patients and in 70% (23/33) of the AD patients. The corresponding data obtained by quantitative evaluation were 41% (7/17) and 71% (15/21), respectively. The vascular reserve capacity, as determined with the acetazolamide test, was preserved visually in 22% (4/18) and quantitatively in 29% (5/17) of the VD patients, but in 73% (24/33) and 76% (16/21) of the AD patients. The differences in the perfusion patterns between the VD and AD patients were statistically significant (P<0.01, Fischer's exact test). Of the VD patients with hypoperfusion (bilateral temporal and/or parietal), 4/6 (67%, visual evaluation) and 4/7 (57%, quantitative evaluation) had a decreased vascular reserve capacity as determined with the acetazolamide test. In the AD group of patients the corresponding results were 3/23 (13%) and 4/15 (27%). It is concluded that the acetazolamide test is promising in rCBF SPET to differentiate VD from AD.

Pathological regional cerebral blood flow in opiate-dependent patients during withdrawal: a HMPAO-SPECT study.

The aims of the present study were to investigate regional cerebral blood flow (rCBF) in heroin-dependent patients during withdrawal and to assess the relation between these changes and duration of heroin consumption and withdrawal data. The rCBF was measured using brain SPECT with 99mTc-HMPAO in 16 heroin-dependent patients during heroin withdrawal. Thirteen patients received levomethadone at the time of the SPECT scans. The images were analyzed both visually and quantitatively. A total of 21 hypoperfused brain regions were observed in 11 of the 16 patients. The temporal lobes were the most affected area, hypoperfusions of the right and left temporal lobe were observed in 5 and 5 patients, respectively. Three of the patients had a hypoperfusion of the right frontal lobe, 2 patients showed perfusion defects in the left frontal lobe, right parietal lobe and left parietal lobe. The results of the quantitative assessments of the rCBF were consistent with the results of the qualitative findings. The stepwise regression analysis showed a significant positive correlation (r = 0.54) between the dose of levomethadone at the time of the SPECT scan and the rCBF of the right parietal lobe. Other significant correlations between clinical data and rCBF were not found. The present results suggest brain perfusion abnormalities during heroin withdrawal in heroin-dependent patients, which are not due to the conditions of withdrawal.

Helping staff cope with change.

Resistance to change is as inevitable as change itself. But successful leaders can help their staff come to terms with a new culture by understanding the process of grief that accompanies change and by taking time to see that employees' concerns are addressed.

Tc-99m labeled monoclonal antibodies against granulocytes (BW 250/183) in the detection of appendicitis.

Scintigraphy with Tc-99m labeled antigranulocyte antibodies (BW 250/183 MoABs) was performed in 32 patients with suspected appendicitis. Abdominal imaging (planar/SPECT) was performed 2 hours after injection of the tracer. All patients also had surgery and a histologic examination of the resected tissue. Of the patients, 17 suffered from "acute appendicitis" and 12 had right positive scans (sensitivity = 70.6%). In 15 patients, acute appendicitis could have been ruled out, and in 11 of these cases the scan was true negative (specificity = 73.3%). The overall accuracy was 71.8% (23/32 cases). The use of Tc-99m antigranulocyte MoABs may overcome the problems associated with the Tc-99m HMPAO granulocyte and In-111 oxine approaches, which include nonspecific intestinal activity or the lack of timeliness. The use of Tc-99m labeled antigranulocyte antibodies is suitable as an emergency procedure and may play a role in the management of patients with suspected appendicitis.

Inhalation scintigraphy with an ultrafine aerosol in infants with functional bronchial stenoses.

Evaporation of Tc-99m pertechnetate at about 2500 degrees C on a carbon surface generates an ultrafine aerosol of Tc-99m-labeled carbon clusters (Technegas). The small particle size of about 100 nm enables the aerosol to behave similarly to a gas in its ability to penetrate. After inhalation, the radioactive particles adhere to the walls of the respiratory bronchioles and alveoli, or to the greater bronchial tubes if the airflow is not laminar. The high concentration of radioactivity in the argon carrier gas makes it possible to perform inhalation scintigraphy after only a few breaths. The authors investigated 24 infants with multiple events of bronchitis, most of whom had pneumonia. Seventeen patients had inhalation scintigraphy and bronchoscopy. Of these, 11 had scans diagnostic of bronchial stenosis and 6 had normal scans. Except for two pathologic scans, all scintigraphic findings matched well with the results of bronchoscopy. Seven patients had scintigraphy only, of which four were normal. Inhalation scintigraphy with Technegas is a reliable, nonhazardous procedure to preselect young patients for directed bronchoscopy.

Technetium-99m-labeled anti-granulocyte antibodies in suspected bone infections.

The introduction of 99mTc-labeled anti-granulocyte antibodies seemed to provide advantages in comparison with formerly used in vitro methods to label autologous white blood cells for inflammation imaging. For this reason, we have undertaken a study to evaluate the clinical significance of this method. Thirty unselected patients with suspected bone infections were studied prospectively using the monoclonal 99mTc-labeled anti-granulocyte antibody. Twenty patients were referred with suspected infections of the peripheral bones (Group I), as well as 10 patients with suspected infections of the spine (Group II). Planar whole-body scans were performed 4 hr and 20 to 24 hr after administration of 500 MBq of the labeled antibody. Scans were considered positive for a bacterial (septic) infection when a focally increased antibody accumulation occurred. All scans were evaluated in blinded fashion by two experienced readers. Of the 20 studies from Group I patients, four false-positive scintigraphic findings were observed, and one false-negative, resulting in a specificity of only 64% and a sensitivity of 89%. In Group II (10 studies), five scans were true-negative, and five false-negative. For both groups, the specificity of the scintigraphic method was quite low (75%), and the sensitivity was also relatively low (57%). The results of this study demonstrate that in an unselected patient population in whom the diagnosis is not known, scintigraphy with 99mTc-anti-granulocyte antibodies is not a reliable method for detecting septic inflammatory lesions: In addition, use of this method excludes septic lesions with only a moderate likelihood (83% negative predictive value).

[99mTc-anti-granulocyte antibodies (BW 250/183) in the detection of appendicitis]. / 99mTc-Anti-Granulozyten-Antikörper (BW 250/183) zum Nachweis der Appendizitis.

Scintigraphy with 99mTc-labeled anti-granulocyte antibodies (AGAb) was performed in 50 patients with suspected appendicitis. Sequential and static imaging as well as SPECT of the pelvis and abdomen was performed 2 h p.i. In all patients the diagnosis was confirmed either histologically or by long-term follow-up. 13 patients had histologically proven acute appendicitis. In 11 patients the appendix scan had been positive and in 2 patients the scan had shown no significant tracer uptake in the right lower abdomen. The remaining 37 patients turned out not to have acute appendicitis. 29 out of these patients had negative and 3 had positive scan findings. In 5 patients the scan was equivocal. Out of these patients 2 had pathologic findings on the left side of the abdomen which turned out to be acute diverticulitis in one patient and acute peritonitis in the other. The remaining 3 patients with unclear scintigraphic findings had no acute appendicitis. Scintigraphy with AGAb is fast and easy to perform and thus superior to cell labeling methods for diagnosing acute appendicitis. Sensitivity for the diagnosis of acute appendicitis was 85% with a specificity of 91%. Chronic or scarred non-granulocytic appendicitis--in which there is often no definite indication for surgery--was negative in our study except for two cases.

[HMPAO-SPECT during carotid artery compression (Matas test) in the evaluation of cervical tumor surgery with potential carotid involvement]. / HMPAO-SPECT unter Karotiskompression (Matas-Test) in der Diagnostik vor zervikalen Tumoreingriffen mit möglicher Karotisbeteiligung.

For planning the surgical approach in patients with head and neck tumours and extensive cervical metastasis the evaluation of possible vascular involvement is necessary. If the carotid artery is suspected to be infiltrated by the tumour masses its resection or plastic substitute becomes sometimes inevitable. For evaluation of the collateral brain perfusion before a possibly necessary carotid resection we examined 10 patients with neck tumours performing the Matas-Test combined with HMPAO Single-Photon-Emission-Computed-Tomography. During ultrasound-controlled manual compression of the involved common carotid artery 99mTc-labelled HMPAO was injected. The SPECT demonstrated the brain perfusion during the carotid compression time period. 6 patients showed a decreased perfusion of the affected hemisphere with - as far as obtained - normal baseline SPECT-results and balloon occlusion tests. 2 of these patients underwent a carotid artery resection, one of the common carotid artery and one of the internal carotid artery. One patient had a significant perfusion deficit in the SPECT but no pathologic findings in angiography and balloon occlusion test. He suffered from hemiparesis postoperatively. The other patient showed preoperatively a minor decrease in perfusion and had no neurological defects postoperatively. Our findings show that the Matas-Test combined with HMPAO-SPECT is a valuable tool for the preoperative evaluation of the collateral brain perfusion. This technique is not invasive and can be performed in every nuclear medicine department with an ECT camera. The HMPAO-SPECT during carotid compression can add useful information or even replace angiography and the balloon occlusion test.

[A comparison of 201Tl and 99mTc-MIBI in the follow-up of differentiated thyroid carcinomas]. / Vergleich von 201Tl und 99mTc-MIBI in der Nachsorge des differenzierten Schilddrüsenkarzinoms.

12 patients with suspected recurrence of differentiated thyroid carcinoma following thyroidectomy, radioiodine therapy and, in some cases, external radiation therapy had 201Tl and 99mTc-MIBI scintigraphy. Except in one case, the findings concerning tumor localization and extension were identical. In all cases, locoregional lymph node metastases as well as osseous metastases were imaged by 201Tl and 99mTc-MIBI scintigraphy. MRI images obtained in all patients with suspected lymph node metastases revealed inoperable situations in 2 cases, whereas there was no correlation in 1 patient with positive 201Tl and 99mTc-MIBI scintigraphy. In contrast, the sensitivity of the two methods was relatively low in the detection of pulmonary metastases which were imaged in 1 out of 3 patients only. Discrepancies between 201Tl and 99mTc-MIBI were observed in a case of axillary lymph node metastasis. Although tumor-/background ratios were slightly higher for 201Tl, 99mTc-MIBI SPECT showed a higher imaging quality compared to 201Tl SPECT, especially in deeply situated tumor lesions. In conclusion, 99mTc-MIBI seems to be a promising alternative imaging agent in the follow-up of differentiated thyroid carcinomas.

[Increased sensitivity of whole-body scintigraphy with I131 for the detection of iodine-accumulating metastases by means of delayed imaging]. / Erhöhte Sensitivität der Ganzkörperszintigraphie mit 131J für den Nachweis jodspeichernder Metastasen durch spätere Aufnahme-Zeitpunkte.

In the follow-up of thyroid cancer patients we sometimes observed discrepancies between elevated thyroglobulin levels and negative results of posttherapeutic or diagnostic scans 48 h and 72 h after oral application of 131I routinely. Consequently, delayed 131I scans (96 h and later) were performed in addition. In all cases, delayed 131I scans either showed a higher imaging quality or additional metastatic lesions. Thus, posttherapeutic (and diagnostic) scans should include late images (4 d and later).

[Early and late HMPAO-SPECT during an epileptic seizure]. / Frühe und späte HMPAO-SPECT während eines epileptischen Anfalls.

For presurgical evaluation of epilepsy a 44-year old patient with complex-partial seizures underwent HMPAO-SPECT. The morphology of the seizures, the MRI-scan, psychometry and ictal as well as interictal EEGs showed a left temporal origin of the seizures. Early images were obtained 20 min and late images 24 h following injection. On both scans a marked hyperperfusion was observed in the left temporal area. A crossed cerebellar diaschisis was also seen on both SPECTs. It could be shown that during ictal examinations there is no bloodflow-dependent wash-out from brain tissue.

Cholecystokinin octapeptide, caerulein, substance P, neurotensin, and angiotensin II: species-typical effects on the isolated portal vein of guinea pig and rat.

The isolated, spontaneously active portal vein of guinea pig was stimulated by the following compounds (the pD2 is given in parentheses): caerulein (CER, 8.02), cholecystokinin octapeptide (CCK-8, 7.59), substance P (SP, 4.68), and carbachol (5.37), whereas neurotensin (NT) was ineffective and angiotensin II (AII) produced inhibition. On the portal vein of the rat, CER and CCK-8 were ineffective, whereas stimulation occurred with SP (5.72), NT (6.79), AII (7.89), and carbachol (5.50). Tetrodotoxin did not modify these effects in both types of preparation. Cyclic dibutyryl guanosine monophosphate reduced the effect of CCK-8 and CER but not that of carbachol. It is concluded that the peptides stimulate the portal vein in a way independent from intramural neurons. It may be speculated that receptors for CCK-8 and CER are absent in the portal vein of rat and those for NT in the guinea pig vein.