[Calcification of the basal nuclei in hypoparathyroidism. The computed and magnetic resonance tomographic aspects]. / Calcificazione dei nuclei della base nell'ipoparatiroidismo. Aspetti con tomografia computerizzata e con risonanza magnetica.

Six female patients with hypoparathyroidism (2 idiopathic and 4 postoperative cases following total thyroidectomy) were examined with brain CT scans; 4 of them underwent MR exams too. Two patients presented with no symptoms, 4 exhibited extrapyramidal syndrome, tetany, fainting seizures or ischemic attacks and only 2 presented with abnormal calcium-phosphorus balance. CT showed calcifications of the basal nuclei in 5 patients. The caudate nucleus was always affected (100%). The calcifications were in the putamen, globus pallidus and thalamus in 4 cases (80%), in the dentate nuclei, centrum semiovale and cerebral cortex in 2 cases (40%) and in the mesencephalic gray matter in 1 case (20%). In one case only CT failed to detect the abnormalities, which were nevertheless depicted by MRI. In the other 3 patients who underwent MRI, CT findings were confirmed as low-signal areas on SE T1- and T2-weighted MR scans where the calcifications were present, but areas of increased signal intensity were also evident on SE T2-weighted images; in one patient, low-signal areas were surrounded by a ring of increased signal intensity on SE T1-weighted scans. Low-signal areas reflect an early stage of calcium deposition; on the other hand, high-signal areas are probably caused by proteins and mucopolysaccharides or by liquid pools secondary to endothelial membrane incompetence. CT better defined the site and extent of the calcifications which may be found in both idiopathic and postoperative hypoparathyroidism, in symptomatic or asymptomatic patients. On the other hand, MRI seems to be capable of depicting the various stages of calcium deposition on the basis of the presence of reduced or increased SE T2 signal intensity.

[Inverted axis scans in the study of the lumbo-sacral passage with computed tomography]. / Scansioni con asse inverso nello studio dello spazio di passaggio lombo-sacrale con Tomografia Computerizzata.

In the CT study of the lumbosacral spine, the disk spaces must be scanned along a plane which parallels the relative intervertebral disk perfectly. However, the lumbosacral space often happens to be too oblique--i.e., over the possible inclination of the gantry (usually: +/- 25 degrees). Thus, the somatic planes of the spine overlap. Therefore, in a series of 1,800 patients, the lumbosacral space was studied with the gantry inclined in the opposite direction to that in conventional scans, with the maximum angle allowed by our unit (-25 degrees). The incidence of negative findings for disk conditions was 7% (versus 13.5% with conventional CT). In both the negative and the positive cases, inversion CT scans were diagnostic in 594 patients (468 with disk herniation)--i.e., in 33% of cases.

[Role of computerized tomography in the densitometric assessment of lithiasis of the gallbladder]. / Ruolo della tomografia computerizzata nella valutazione densitometrica della litiasi della colecisti.

Radiolucent gallstones frequently contain significant calcium deposits. Their detection is important to select the patients to submit to medical gallstone dissolution. Since CT facilitates the identification of calcifications undetected at conventional radiologic procedures, 60 patients were studied with CT. All of them had US confirmation of cholelithiasis and in the whole of cases an X-ray examination of the right upper abdominal quadrant was performed (for the identification of radiopaque stones), together with oral cholecystography (to evaluate gallbladder function). CT attenuation values of the stones were measured and the patients subsequently divided into 2 groups; the threshold value was 50 HU: below it, the stones were considered hypo- or isodense (group I); above it, they were considered hyperdense (group II). Later on, 28 patients (14 from group I and 14 from group II) were selected for chemical dissolution with ursodeoxycholic acid over a 1-year period. US examinations were performed at 6 and 12 months. Seventy per cent of the patients in group I responded to treatment (50% with complete stone dissolution and 20% with partial dissolution), whereas no patient in group II had complete dissolution and only 30% had partial response.

[Ultrasonography and computerized tomography in the diagnosis of gallbladder carcinoma]. / Ecografia e tomografia computerizzata nella diagnosi del carcinoma della colecisti.

The US and CT images of 40 surgical patients with histologically proved gallbladder carcinoma were retrospectively reviewed. The radiologic diagnosis was correct in 22 patients (55%). Gallbladder carcinoma patterns were: an intraluminal mass (type I) (7 patients, 17.5%), focal or diffuse wall thickening (type II) (5 patients, 12.5%) a mass replacing the gallbladder (type III) (10 patients, 25%). In 5 patients with type I or II gallbladder carcinoma, US and CT diagnosis was made easier by the presence of associated findings--i.e., liver infiltration and/or metastases, lymphadenopathy, dilated intrahepatic ducts, ascites. In 7 patients a gallbladder carcinoma was suspected in the presence of a small intraluminal mass (6 cases) or of focal wall thickening (1 case), with no stones and with dilated intrahepatic biliary ducts. In the extant 18 patients (45%) the radiologic diagnosis was: polyps (6 cases), stones with cholecystitis (11 cases) and empyema (1 case). US is the examination of choice in the diagnosis of gallbladder and biliary ducts conditions, but several diagnostic problems may arise in the differentiation from polyps and acute inflammatory disease. CT better demonstrates gastrointestinal tract invasion and lymphadenopathy, which can be a valuable finding for treatment planning.