[Cerebral single-photon emission-computed tomography. A semiquantitative analysis of vascular areas in patients with cerebrovascular pathology]

BACKGROUND

Brain SPECT perfusion studies in patients with cerebral stroke may be useful to evaluate distant perfusion abnormalities.

METHODS

99mTc-HMPAO brain SPECT studies were performed in 17 patients with ischemic lesions in the basal ganglia and/or internal capsule demonstrated by NMR. Regions of interest were adjusted in representative transverse slices to the vascular territories of the anterior, middle, posterior and communicating cerebral arteries.

RESULTS

Patients with ischemic lesions in the right basal ganglia showed increased cerebral perfusion in the left middle artery territory (0.95 +/- 0.13 versus 0.80 +/- 0.06; p = 0.0365). Patients with ischemic lesions in the left basal ganglia showed increased perfusion in the right anterior artery territory (0.93 +/- 0.09 versus 0.82 +/- 0.09; p = 0.0464), in the left anterior artery territory (0.93 +/- 0.09 versus 0.83 +/- 0.14; p = 0.0464), in the left middle artery territory (0.92 +/- 0.09 versus 0.78 +/- 0.05; p = 0.0079) and in the left posterior artery territory (1.05 +/- 0.14 versus 0.90 +/- 0.09; p = 0.036). Patients with ischemic lesions in the right internal capsule showed increased perfusion in the right posterior artery territory (0.95 +/- 0.11 versus 1.10 +/- 0.18; p = 0.0431).

CONCLUSIONS

These results show the presence of delayed luxury perfusion phenomena in regions distant from the ischemic site.

Cognitive correlates of ventricular enlargement in vascular patients with leuko-araiosis

We studied the cognitive significance of ventricular enlargement in 40 vascular patients with leuko-araiosis on MRI. We obtained significant differences between patients and normal controls without vascular risk-factors regarding ventricular measures. Ventricular size of the patients correlated with several neuropsychological tests measuring abstract reasoning, comprehension of language, constructional skills, speed and attention. These results suggest that ventricular enlargement in vascular patients reflects global deterioration of complex cognitive functions. Information proceeding from ventricular size is complementary to that coming from the degree of leuko-araiosis and probably has more clinical significance. Both leuko-araiosis and ventricular size may be neuroimaging parameters capable of reflecting the cognitive deterioration in vascular patients without large lesions.

Left-ear extinction in patients with MRI periventricular lesions

A dichotic listening test was administered to 22 elderly vascular patients with periventricular white matter changes on magnetic resonance imaging. We found four patients with a moderate-to-severe extent of these changes who showed a pattern of left-ear extinction. These findings suggest that periventricular lesions in patients with vascular risk factors may be associated with a functional disconnection of the interhemispheric auditory pathways.

Wallerian degeneration of the pyramidal tract in capsular infarction studied by magnetic resonance imaging

Using magnetic resonance imaging, we studied 24 patients with ischemic infarction of the internal capsule. Magnetic resonance imaging detected wallerian degeneration of the pyramidal tract below the capsular lesion in 11 patients (45.8%); all 11 had clinical evidence of pyramidal tract damage. In six additional patients magnetic resonance imaging findings, present only on axial slices, were considered to indicate possible wallerian degeneration. When motor deficit was associated with posterior limb lesions, magnetic resonance imaging detected wallerian degeneration of the pyramidal tract in 78.6% (11) of 14 patients.

Leuko-araiosis on magnetic resonance imaging and speed of mental processing

The clinical significance of white matter abnormalities seen in brain imaging studies, termed leuko-araiosis (LA), still remains uncertain. Leuko-araiosis has been associated with a global decline in cognitive performance, although little is known about the cognitive functions that LA may account for. We present the correlates between LA severity on magnetic resonance imaging and mental deterioration in a selected sample of 41 elderly patients with vascular risk factors. We found that LA was related to performance on tasks measuring the speed of information processing and, in particular, on those that involve complex processes. This impairment can be important in producing reduction in daily living activities as it is in the support to the relationship found with some commonly used behavioral rating scales. Leuko-araiosis is also related to the presence of some primitive reflexes, suggesting that their disinhibition may be due to diffuse corticofugal fibers damage.

Lacunar cerebral infarct and nuclear magnetic resonance. A review of sixty cases

A prospective series of 60 consecutive patients with lacunar cerebral infarcts (LI), studied using nuclear magnetic resonance (MR) and brain computerized tomography (CT), is presented. A significantly greater number of positive results (p less than 0.001) was observed in the MR (78%) in comparison with the CT scan (30%). In pure motor hemiparesis, the number of positive results obtained with MR was maximal (85%) and greater than with CT scan (35%; p less than 0.001). In pure sensory stroke, the positivity was 40% in MR and 20% in CT. In pontine and capsular topography, MR showed a greater sensitivity than CT scan (p less than 0.001). A significantly (p less than 0.001 greater number of silent infarcts were detected by MR (42%) than by CT scan (18.5%). Nowadays, MR is the complementary examination of choice in the topographic diagnosis of LI and should be carried out whenever possible in all patients presenting with this pathology.

[Computerized x-ray tomographic aspects of calcifying hepatic metastases. Incidence of cancer of colorectal origin]

A total of 24 patients with liver metastases of the calcifying type were detected during CT scan imaging for cancer of different primary origin (colorectal, ovarian, mammary, gastric, prostatic, melanoma). These calcifying metastases represented 27% of the 89 liver metastases cases detected, and the incidence of a colorectal origin for these calcifying lesions (20% of cases) appears to be highly significant, their number being relatively larger than reported in previous studies. Identification of liver calcifications of possible diagnostic importance requires a two-stage CT scan investigation, before and after bolus. Paraclinical examinations should be directed selectively towards the digestive tract when the primary tumor is unknown.

Ideal imaging in MR: contrast-enhancing pharmaceuticals. Evaluation of tempo carboxylic acid as nitroxide diagnostic agent

The meglumine salt of TCA, a piperidinyl nitroxide stable free radical derivative, was tested as an NMR contrast enhancer. This report of its use in animals indicates its usefulness in the enhancement of signal intensity of the kidney and bladder.

[Pseudotumoral retroperitoneal tuberculosis. Apropos of a case]

A case is reported of pseudotumoral retroperitoneal tuberculosis with invasion of left supraclavicular glands. Relative diagnostic efficacy of ultrasound and CT scan imaging is discussed as well as the differential diagnosis of this exceptional lesion. Exploratory procedures suggested with this type of picture are ultrasonography. CT scanning and possibly guided needle puncture biopsy to avoid surgical exploration. The value of the scanner for follow up review of results of antituberculosis treatment is emphasized.

Breast pathology in MRI. First results

The authors present the first results of the assessment of MRI (0.35 T) with adapted surface reel in the exploration of mammary pathology in 90 cases. On a morphological level, MRI permits a new analysis of signs of dystrophy. As far as MRI is concerned, no specific sign of mammary neoplasia seems to exist. A classification is suggested, taking into account morphology and parameters of relaxation.

[Bone x-ray computed tomographic densitometry by the dual energy technic in a single rotation. Initial results]

Computed tomography is one of the most promising methods for the non-invasive measurement of the bone mass. A review of the theoretical bases of the double energy technique developed by the authors' experimental study on tubes containing defined calcium concentrations and on cadaver vertebrae, demonstrates the value of this investigation in this field. The theoretical study also reveals the limitations of the technique, in particular the decrease in the values induced by fat. The value of this new technique has been confirmed by the preliminary clinical results obtained in non-osteoporotic control women and in women with confirmed osteoporosis, which obviously need to be confirmed by larger series.