Detection of postoperative deep-venous thrombosis using technetium-99m-labeled tissue plasminogen activator.

UNLABELLED: The current noninvasive methods of deep-venous thrombosis (DVT) detection in the asymptomatic patient are sufficiently inaccurate so as to preclude their routine use. This present study reports the accuracy of scintigraphic scanning with 99mTc-rt-PA in asymptomatic postoperative patients using contrast venography as the gold standard. METHODS: Fifty-three consecutive postarthroplasty patients (30 THR, 23 TKR) (16 women, 37 men; mean age 71 yr; range 52-85 yr) underwent scintigraphic scanning with 99mTc-rt-PA and contrast venography, on the operated leg, in order to assess the accuracy of this new technique in these asymptomatic patients. RESULTS: Eighty-four segments were of diagnostic quality on contrast venography. Of the 15 thrombosed segments, 14 had positive scans. In the 69 nonthrombosed segments, 63 had negative scans. Thus, scintigraphic scanning with 99mTc-rt-PA had a sensitivity of 93% and a specificity of 91%. CONCLUSION: This study demonstrated that scintigraphic scanning with modified 99mTc-rt-PA is accurate in the detection of DVT in patients undergoing total hip or total knee arthroplasty.

Technetium-99m-modified recombinant tissue plasminogen activator to detect deep venous thrombosis.

UNLABELLED: We report a method for deep venous thrombosis (DVT) detection which uses 99mTc-labeled modified recombinant tissue plasminogen activator (rt-PA) scintigraphy. A Phase III clinical trial was performed on 79 patients with suspected DVT. METHODS: The plasminogen binding site of rt-PA was permanently inhibited without inactivating the fibrin binding site. The modified molecule was radiolabeled with 99mTc. Scintigraphy was performed and the results were compared to those of contrast venography. RESULTS: Of 14 thrombosed proximal segments, 13 had positive scans; in the 53 nonthrombosed proximal segments, 49 had negative scans. In proximal vein thrombosis, rt-PA scintigraphy had a sensitivity of 93% and a specificity of 92%. Of the 36 thrombosed calf vein segments, 31 had positive scans; in the 30 nonthrombosed calf segments, 28 had negative scans. In calf vein thrombosis, scanning has a sensitivity of 86% and a specificity of 93%. CONCLUSIONS: Scintigraphic scanning with this 99mTc modified rt-PA permits accurate detection of thrombus in both proximal and calf veins in patients with clinically suspected DVT. The technique detects both fresh and aged thrombi and is unaffected by heparin administration. Further study in other patient groups is needed to define the overall clinical utility.

Effect of prehatching weightlessness on adult fish behavior in dynamic environments.

At 16-17 months of age, three groups of fish from the embryonated eggs in the ASTP killifish experiment were subjected to postflight tests consisting of rapidly changing environments. It was found that the group of fish with the least amount of development at orbital insertion (A-32) had a decreased rheotropism for both the moving background and the rotating water current tests when compared to ground control fish. Exposure to parabolic aircraft flight conditions revealed that the A-32 fish were less disoriented during zero gravity periods and were hypersensitive to high-gravity periods. These results suggested a modified vestibular competency due to a 9-d prehatching weightlessness exposure.

Evaluation of white cell scintigraphy using indium-111 and technetium-99m labelled leucocytes.

Indium-111 oxine labelled leucocyte (111In oxine leucocyte) scintigraphy is the test of choice in detecting occult infection and localising focal inflammation. 111In oxine labelling is technically difficult and expensive and leucocyte labelling with technetium-99m stannous colloid (99mTc Sn colloid) has been considered to be an alternative. Leucocytes from 40 cases referred for investigation of occult infection or localisation of inflammation were simultaneously labelled with 111In oxine and 99mTc Sn colloid with dual isotope acquisition performed at 1, 3 and 24 h. Twenty-four hour 99mTc Sn colloid scans were corrected for 111In downscatter. Each case was independently interpreted by two experienced observers. Twenty-one patients demonstrated positive 111In oxine leucocyte scans. Using 111In oxine leucocyte scans as the gold standard, 99mTc Sn colloid leucocyte scanning had an overall sensitivity of 86% and a specificity of 95%. Clinical follow-up verified that three patients had false negative 99mTc Sn colloid leucocyte scans and one patient had a false positive. Further clinical evaluation of 99mTc Sn colloid labelled leucocytes is required before they can become a reliable replacement for 111In oxine leucocytes.

Reproducibility of lateral spine scans using dual energy X-ray absorptiometry.

Reproducibility of lateral spine dual energy X-ray absorptiometry (LAT DEXA) scans using a Lunar DPX-L scanner was assessed in a cadaveric phantom and in patients. One hundred phantom measurements over 7 months demonstrated a longitudinal stability of 1.7% (coefficient of variation, CV). Additional scans were performed with the phantom rotated by up to 20 degrees in each of the three orthogonal planes to assess the effects of variable patient positioning. Horizontal and vertical rotation of the spine had little effect on the estimated bone mineral density (BMD), however, axial rotation of greater than 8 degrees led to errors in the BMD measurement. One hundred consecutive patients had two lateral scans performed within 1 month. BMD (range 0.10-1.6 g/cm2) was determined for each scan by one operator. Significant overlap from ribs and pelvis was often seen with L2 and L4 vertebrae but one vertebra (L3) could be measured in every case. Intraoperator and interoperator variability was assessed by three experienced operators, each analyzing 10 patients' scans on five separate occasions, and was found to be less than 1.1% for a single vertebra. BMD estimation of vertebral bodies and midslices by lateral DEXA scans (CV% of 3.8% and 4.6%) have a 95% confidence interval of 0.074 g/cm2 and 0.096 g/cm2, respectively for two vertebrae. This variability is due mainly to axial rotation, with operator variability, horizontal rotation, and vertical rotation having little effect on BMD estimation.

The relationship between parental history and substance use severity in drug treatment patients.

The authors explored the relationship between the history of parental problematic alcohol and drug use and their adult children's alcohol and drug use disorders. Subjects were 347 admissions to an outpatient substance abuse program. There was a positive relationship between the number of parents affected by alcohol and/or drug problems and the percentage of probands with co-existing alcohol and drug use disorders for probands with alcohol use disorders but not for those with only drug abuse. Probands with two affected parents had significantly higher alcohol abuse scores and drug, family, and psychiatric composite test scores than those with a negative family history. This preliminary study indicates that the severity of a proband's substance use disorder may be influenced by parental substance use history.