James S. Nagel

Recombinant tissue-type plasminogen activator versus a novel dosing regimen of urokinase in acute pulmonary embolism: a randomized controlled multicenter trial

Thrombolysis of acute pulmonary embolism can be accomplished more rapidly and safely with 100 mg of recombinant human tissue-type plasminogen activator (rt-PA) (Activase) than with a conventional dose of urokinase (Abbokinase) given as a 4,400-U/kg bolus dose, followed by 4,400 U/kg per h for 24 h. To determine the effects of a more concentrated urokinase dose administered over a shorter time course, this trial enrolled 90 patients with baseline perfusion lung scans and angiographically documented pulmonary embolism. They were randomized to receive either 100 mg/2 h of rt-PA or a novel dosing regimen of urokinase: 3 million U/2 h with the initial 1 million U given as a bolus injection over 10 min. Both drugs were delivered through a peripheral vein. To assess efficacy after initiation of therapy, repeat pulmonary angiograms at 2 h were performed in 87 patients and then graded in a blinded manner by a panel of six investigators. Of the 42 patients allocated to rt-PA therapy, 79% showed angiographic improvement at 2 h, compared with 67% of the 45 patients randomized to urokinase therapy (95% confidence interval for the difference in these proportions [rt-PA minus urokinase] is -6.6% to 30.4%; p = 0.11). The mean change in perfusion lung scans between baseline and 24 h was similar for both treatments. Three patients (two treated with rt-PA and one with urokinase) had an intracranial hemorrhage, which was fatal in one. The results indicate that a 2-h regimen of rt-PA and a new dosing regimen of urokinase exhibit similar efficacy and safety for treatment of acute pulmonary embolism.

I-123 Iofetamine SPECT Scan in Systemic Lupus Erythematosus Patients with Cognitive and Other Minor Neuropsychiatric Symptoms: A Pilot Study

Accurate diagnosis of central nervous system (CNS) lupus remains difficult, especially when the manifestations are of subtle cognitive and affective changes. This pilot study reports on the use of I-123 iofetamine single photon emission computerized tomography (SPECT) scans in 18 such patients with documented systemic lupus erythematosus. Eight of the 18 scans were abnormal (44%), four in a diffuse bitemporo-parietal pattern previously noted only in Alzheimers disease, and four with large focal deficits. Neither the existence of the abnormal scan nor the particular pattern of abnormality correlated with the results of other diagnostic tests. These preliminary results raise the possibility that SPECT scans may offer an additional valuable diagnostic instrument in CNS lupus, although further studies are necessary to delineate their precise role.

The scintigraphic evaluation of Huntington's disease and other movement disorders using single photon emission computed tomography perfusion brain scans

The increasing availability of single-photon emission computed tomography (SPECT) perfusion brain scans has led to the investigation of a variety of neuropsychiatric conditions including the movement disorders such as Huntingtons and Parkinsons disease. In general, observers have noted that Huntington patients have bilaterally decreased uptake of technetium 99m HM-PAO and iodine 123 IMP in the basal ganglia regions involving the heads of the caudate nucleic and adjacent structure, which reflects decreased neuronal function. These functional changes precede the morphological changes due to caudate nucleus atrophy that are observed on computed tomography and magnetic resonance imaging. Cortical changes occur in severely diseased Huntingtons patients but are more nonspecific. Prediction of individuals at risk for Huntingtons disease using SPECT scans should be done with caution and in association with other clinical data. In contrast, in Parkinsons disease mild diffusely decreased perfusion is commonly noted throughout the cerebral structures, except for the cerebellum. In Parkinsons disease, there is less agreement among observers as to whether the basal ganglia are abnormal. Some observers report that there are no specific basal ganglia perfusion defects in excess of those changes seen elsewhere in the brain. Others report diminished basal ganglia uptake associated with L-dopa therapy in some Parkinsons patients, and in patients with hemi-parkinsonism there have been perfusion deficits reported in the contralateral basal ganglia. In some Parkinson patients, bilateral Alzheimers-like posterior temporoparietal cortical perfusion defects have been observed in association with progressive dementia. Basal ganglia and cortical perfusion changes also have been reported in a few patients with a variety of other less common movement disorders.

SNM Practice Guideline for Brain Death Scintigraphy 2.0

1Beth Israel Deaconess Medical Center, Boston, Massachusetts; 2Mallinckrodt Institute of Radiology, St. Louis, Missouri; 3University of Michigan Medical Center, Ann Arbor, Michigan; 4Brigham and Women’s Hospital, Boston, Massachusetts; 5University of Pisa Medical School, Pisa, Italy; 6VA Boston Healthcare System, West Roxbury, Massachusetts; 7St. Jude Children’s Research Hospital, Memphis, Tennessee; and 8Vanderbilt University, Nashville, Tennessee