Search

Dementia of frontal type (DFT) is a fairly common degenerative disease distinct from Alzheimer's disease (AD), whose reportedly distinctive instrumental feature is frontal lobe hypoperfusion on SPECT. We evaluated the cortical dopaminergic system in 6 AD, 5 DFT, and 6 control subjects with SPECT and both [99Tc]-HM-PAO, a perfusion tracer, and [123I]-IBZM, a D2 postsynaptic ligand. Both in AD and DFT patients, [99Tc]-HM-PAO SPECT showed a relative frontal hypoperfusion. On the contrary, [123I]-IBZM SPECT showed significantly reduced ligand uptake in superior frontal regions of DFT (0.89 +/- 0.08 relative to control subjects) as compared to AD patients (0.97 +/- 0.02; difference of means: 0.08, 95% Confidence Interval 0.004 to 0.156; p = 0.041). Results suggest more marked involvement of the frontal cortical dopaminergic system in DFT than in AD patients.

Necrotizing external otitis (NEO), or malignant external otitis, a severe penetrating infection of the ear canal and the temporal bone, which occurs almost exclusively in diabetic or immunodepressed elderly patients, is caused in most cases by Pseudomonas aeruginosa while Staphylococcus epidermidis and Aspergillus fumigatus have been described as other possible agents. Recently bone scintigraphy, carried out above all employing SPECT, has been considered an important tool in diagnosis and follow-up of NEO. Many Authors confirm the role taken by Technetium99m-methylene-diphosphonate (MDP) and Gallium67-citrate bone scanning. Benecke suggested that response to therapy could be monitored with Ga67 or In111 scans. Two cases of NEO in which diagnosis and follow-up were made using Tc99m-nanocolloid (NC) SPECT are presented in this paper. The Authors discuss the advantages of this latter radiotracer, compared to those obtained with Ga67-citrate, in the follow-up evaluation of therapy efficacy. Tc99m-NC, in fact, is a better inflammation index in that its fixation on bone tissue is determined by the permeability of the basal membrane of vessels. Furthermore, with Tc99m-NC antibiotic therapy may be continued as long as necessary. Bone scintigraphy with other radiotracers may infact result positive for a long period after disease remission in that their fixation is linked to the one remodelling process.

Single photon emission tomography (SPET) with the novel ligand [123I]-IBZM was used to image central dopamine D2 receptors in Parkinson's disease (PD) patients. The aim was to assess basal ganglia (BG) receptor densities in relation to the response to L-dopa therapy. To better characterize the clinical potential of [123I]-IBZM SPET, each patient underwent a second study with the regional perfusion tracer [99mTc]-HM-PAO. Tracer activity ratios were calculated for caudate and putamen with mean activity over the cerebellar hemispheres as internal standard. In PD patients we found a significant decline of mean caudate [123I]-IBZM activity, as compared with age-matched control subjects. However, when patients were grouped according to their therapeutic behavior, the [123I]-IBZM uptake in BG ganglia regions of the PD patient group with a poor and fluctuating response to L-dopa was significantly reduced from mean values of patients with a sustained response to L-dopa therapy. [99mTc]-HM-PAO caudate and putamen uptake indexes in PD were similar to control values, even in patients with deteriorated therapeutic response. Our results indicate that BG D2 receptor alterations in PD may contribute to the altered response to L-dopa.

A 18 years male had congenital hypoplasia of the right external iliac artery and thrombosis of its narrowest part. Congenital megacolon, anal atresia and hyposomical nanism were also present. Surgical intervention was indicated because he was developing arterial insufficiency and muscular hypotrophy of the right leg. A bypass was performed with a reversed autogenous vein between the common iliac artery and the common femoral artery.

Hepatobiliary scintigraphy with 99mTc-HIDA offers a noninvasive method to detect duodenogastric reflux. Biliary reflux was graded using the persistence rather than the intensity of the radioactive refluxate: Grade 0 was considered the absence of reflux, minimal reflux, or reflux in the first 10-15 min; Grade 1 was repetitive reflux lasting less than 10 min; Grade 2 was persistent reflux; and Grade 3 was reflux up to the esophagus. Twenty-five patients with foregut symptoms were studied and results were compared to 24-hr gastric pH monitoring. Scintigraphy and pH monitoring agreed in 15 out of 25 patients (60%), but no correlation was found with the endoscopic findings. The rationale for this approach is based on pathophysiologic evidence that damage to gastric and/or esophageal mucosa is mainly related to the prolonged contact time with duodenal contents. This technique seems to allow a complete functional evaluation of the esophagogastroduodenal tract without causing adjunctive irradiation or discomfort to the patient.