The validity of Binswanger's disease.
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Brain Diseases↗
Biomedical subjects
M Mascalchi
Publications and source records attributed to M Mascalchi.
Breath-hold spin-echo MR imaging for evaluation of dynamic enhancement of native and treated hepatocellular carcinoma after intravenous Gd-DTPA administration.
Using a simple modification of a standard spin-echo sequence which enable acquisition of three breath-hold images in 15 s, dynamic enhancement of 30 histologically proven hepatocellular carcinomas (17 native tumors, 6 completely necrotic tumors after nonsurgical treatments, and 7 tumors with viable and necrotic portions) after intravenous injection of gadolinium-DTPA was evaluated. Native hepatocellular carcinomas and viable portions in treated nodules showed elective enhancement in images obtained 40 s after contrast injection. Contrast between these lesions and the normal liver decreased thereafter. No contrast uptake was seen in entirely necrotic nodules and necrotic portions of treated nodules. Because of the capability to demonstrate the elective arterial blood supply typical of hepatocellular carcinoma, breath-hold T1-weighted spin-echo sequence should replace conventional T1-weighted images for the evaluation of intravenously administered gadolinium-DTPA enhancement of this tumor before and after nonsurgical treatments.
Aged↗
Liver and spleen enhancement after intravenous injection of carboxydextran magnetite: effect of dose, delay of imaging, and field strength in an ex vivo model.
It has been predicted that liver and spleen enhancement after administration of superparamagnetic contrast agents may be different, depending on the strength of the main magnetic field. With the use of an ex vivo model, we investigated at 0.3, 0.5, and 1.5 T the effects on liver and spleen signal intensity of 5, 15, and 45 mumol/kg body weight of dextran magnetite (SHU 555A) in 54 rats. Nine rats served as controls. At different time delays since injection, the animals were killed, and after perfusion with saline, the liver, brain, and spleen were fixed in formalin. The specimens were embedded in an agar gel matrix and imaged with inversion recovery T1-weighted, proton density spin echo, and T2*-weighted gradient recalled echo (GRE) sequences. At each magnetic field strength, peak liver and spleen signal loss increased with increasing dose of the contrast medium. Signal loss was significantly more conspicuous after a dose of 15 than 5 mumol/kg body weight, but not after a dose of 45 compared with 15 mumol/kg. No signal change was observed in the brain. GRE images showed higher enhancement than proton density-weighted spin echo and inversion recovery images but were noisier. The enhancement showed a plateau between 30 min and 24 hours. Only the signal decrease of the liver after a low dose of contrast medium on GRE images was significantly higher (p < 0.01) at 1.5 than at 0.5 and 0.3 T. Other differences in respect to the field strength were less significant (p < 0.05) or nonsignificant. Differences in the spleen enhancement were nonsignificant. SHU 555A at a dose of 15 mumol/kg is an efficient intracellular contrast agent for liver and spleen at low, mid, and high field strength. Proton density spin echo images are probably the sequence of choice to exploit SHU 555A contrast effects and a wide time window for imaging after its intravenous injection does exist.
Animals↗
Solitary necrotic nodule of the liver: imaging and correlation with pathologic features.
We describe two cases of solitary necrotic nodule of the liver, an uncommon nonmalignant lesion that can mimic a metastasis. The nodule appeared hypoechoic, or targetlike, on sonography, hypodense without contrast enhancement on computed tomography, and hypointense on magnetic resonance imaging, including diffusion-weighted images. These features, peculiar when considered together, are explained by the coagulative type of necrosis.
Adult↗
Small hepatocellular carcinoma: differentiation from adenomatous hyperplasia with color Doppler US and dynamic Gd-DTPA-enhanced MR imaging.
BACKGROUND: To investigate the usefulness of color Doppler ultrasound (US) and dynamic Gd-DTPA-enhanced magnetic resonance (MR) imaging in the differentiation of small hepatocellular carcinoma (HCC) and adenomatous hyperplasia (AH). METHODS: Thirty-eight small (3 cm or less) nodular lesions (in 38 cirrhotic patients) with US features consistent with HCC underwent evaluation with color Doppler US and MR imaging. Breath-hold T1-weighted rapid acquisition spin echo MR sequence after bolus injection of 0.1 mmol/kg gadopentetate dimeglumine was used to evaluate dynamic enhancement. US-guided tissue-core percutaneous biopsy established the diagnosis: HCC in 28 cases and AH in 10. RESULTS: Color signals with pulsatile or continuous Doppler spectrum were demonstrated in 19 of 28 HCCs (68%) but in none of the AHs. Although there was considerable overlap in signal intensity between HCC and AH on both unenhanced T1- and T2-weighted images, early enhancement on breath-hold T1-weighted images obtained 40 s after starting contrast administration was observed in 22 of 28 HCCs (79%) but in none of the AHs. In 26 of 28 HCCs (93%), pulsatile or continuous flow at color Doppler US, early enhancement at dynamic MR imaging, or both were observed. CONCLUSION: Findings with color Doppler US and dynamic Gd-DTPA-enhanced MR imaging enable a reliable distinction between small HCC and AH.
Biopsy↗
Electric and CO2 laser SEPs in a patient with asymptomatic syringomyelia.
We recorded electrically stimulated somatosensory evoked potentials (electric SEPs) and pain-related SEPs following CO2 laser stimulation (CO2 laser SEPs) from a 17-year-old patient affected by myotonic dystrophy whose MRI disclosed a large syrinx extending from spinal level C2 to S3. Careful clinical and electromyographic examinations revealed no motor or sensory disturbances, apart from myotonia. The only abnormality noted in median and ulnar nerve short-latency electric SEPs (recorded with a non-cephalic reference electrode) was the absence of cervical component N13, the other SEP responses (N9, N10, N11, P14, N20) being normal. The cutaneous pain threshold and CO2 laser SEPs (both obtained by a CO2 laser beam applied to the back of the hand) were normal. Thus cervical component N13 appears to be highly sensitive to the effects of central cord lesions, even when these are asymptomatic.
Adolescent↗
MR imaging in a case of Hallervorden-Spatz disease.
Magnetic resonance using a 0.5 T system and a T2-weighted spin-echo pulse sequence revealed symmetric areas of marked hypointensity of the globi pallidi in a case with a family history of and presenting with clinical features consistent with Hallervorden-Spatz disease. No such findings were seen in any of 16 normal volunteers of similar age. Magnetic resonance may be useful for diagnosing Hallervorden-Spatz disease.
Adult↗
Cardiac-gated phase MR imaging of aqueductal CSF flow.
The direction of CSF flow within the cerebral aqueduct was studied by cardiac-gated magnetic resonance (MR) phase images in five healthy volunteers and 10 patients with presumably normal cerebral CSF circulation. Caudal CSF flow was observed during systole and cranial flow during diastole. Using phantom based calibrations of the imager, aqueductal CSF velocities of 3-5 mm/s were calculated. Cardiac-gated phase MR is a potentially major tool for the investigation of the CSF circulation.
Adult↗
Lower cranial nerve palsy due to dissection of the internal carotid artery: CT and MR imaging.
Three patients with unilateral lower cranial nerve palsy underwent contrast enhanced CT and magnetic resonance (MR) imaging for the investigation of possible compressive pathology in the region of the jugular foramen. Computed tomography revealed a mural crescentic hypodensity of the corresponding internal carotid artery (ICA) in two patients and a faulty visualization of the vessel in one. Magnetic resonance revealed a corresponding hyperintense lesion expanding the wall and narrowing the lumen of the cervical ICA on both T1- and T2-weighted images. Dissection of the ICA was confirmed by angiography in all three patients. Among the possible etiologies of lower cranial nerve palsy, a dissecting hematoma of the cervical ICA must be considered, which can be diagnosed by CT and MR.
Aortic Dissection↗
Mottled MR appearance of a hyperacute intracerebral hemorrhage at 0.5 T.
A hypertensive patient was examined by CT and magnetic resonance (0.5 T) within 3 h from stroke onset. Computed tomography revealed a thalamocapsular hemorrhage. Hematoma was isointense to the white matter on T1-weighted and hyperintense on T2-weighted spin echo images. The T2-weighted gradient echo images showed a mixture of hypointense and hyperintense signal. This latter aspect has not previously been reported and is probably related to abundant intracellular deoxyhemoglobin in clotted areas rich in red blood cells.
Acute Disease↗
MRI of wallerian degeneration in the cervical spinal cord.
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Adult↗
Contrast-enhanced time-resolved MR angiography of spinal vascular malformations.
PURPOSE: The purpose of this work was to assess the potential and limitations of a contrast-enhanced time-resolved MR angiography technique for evaluation of spinal vascular malformations. METHOD: Two patients with intramedullary arteriovenous (AV) malformations and three patients with dural AV fistula underwent four serial acquisitions, every 17-20 s, of 20-32 coronal 1.5- to 2-mm-thick partitions with a fast 3D SPGR sequence after injection of 0.2-0.3 mmol/kg paramagnetic contrast agent. This was followed by coronal 3D and sagittal or coronal 2D phase contrast (PC) MR angiography. RESULTS: No spinal vessels were visualized in the first (baseline) series. In patients with intramedullary AV malformations, the arterial feeders, nidus, and perimedullary draining veins were visualized in the second (early) series. In the third (intermediate) series, the arterial feeder vanished, whereas the intercostal and lumbar veins appeared. In patients with dural AV fistula, abnormal intraspinal vessel appeared in the third series and persisted, although less conspicuous, in the fourth (late) series. Contrast-enhanced time-resolved MR angiography demonstrated the venous components of the lesion with better conspicuity than 3D PC MR angiography, whereas it was inferior for visualization of arterial feeders. Moreover, indirect identification of the level of the dural AV fistula was possible only on the phase display of the 2D PC MR angiography. CONCLUSION: Contrast-enhanced time-resolved MR angiography is a useful complement to PC MR angiography for the evaluation of spinal vascular malformation.
Arteriovenous Fistula↗
[Hemorrhagic encephalopathy due to cyclosporin 1 year after heart transplantation. A case report].
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Adult↗
[High resolution and spirometric synchronization computerized tomography in chronic obstructive bronchopneumopathy].
PURPOSE: To assess the feasibility of spirometrically gated HRCT in patients with chronic obstructive pulmonary disease and to correlate the density measures with the results of pulmonary function tests. MATERIAL AND METHODS: Pulmonary function tests and spirometrically gated HRCT were performed, on the same day, in 20 patients with chronic obstructive pulmonary disease. Spirometrically gated HRCT scans at 90 and 10% of the patient's vital capacity were acquired, at three anatomical levels (carena, carena plus 5 cm, carena minus 5 cm). In each section, lung parenchyma was isolated from the other thoracic structures and from the main bronchi and a densitometric evaluation was applied to the regions of interest. A histogram showing the distribution of the pixel frequencies versus lung densities, the mean CT number and the pixel index at -910 HU (for scans acquired at 10% of the patient's vital capacity) and at -950 HU (for scans obtained at 90% of the patient's vital capacity) were obtained. Average acquisition time for the spirometrically gated HRCt was 15-20 minutes, average data processing time was 20 minutes. RESULTS: The mean CT number and the pixel index at -910 HU obtained at 10% of the patient's vital capacity correlated with the Tiffeneau index (r = 0.85; R = 0.78 respectively). The pixel index at -910 HU correlated also with the ratio of residual volume to total lung capacity (r = 0.65). The mean CT number and the pixel index obtained at 90% of the vital capacity correlated with the lung diffusion of carbon monoxide (r = 0.64 and r = 0.79 respectively). CONCLUSIONS: In our study, we found good correlation between the densitometric values obtained with spirometrically gated HRCT and the respiratory function tests routinely employed to assess the presence and the gravity of obstructive pulmonary disease. A good reproducibility of the data is guaranteed by the spirometical gating which enables standardization of the lung acquisition volume, and by the semiautomatic contour tracing program combined with an automated densitometric evaluation. The main disadvantages of the technique are the relatively long acquisition and evaluation times. Spirometrically gated HRCT densitometry is a promising tool for longitudinal studies of diffuse lung disease (pulmonary emphysema and fibrosis).
Adult↗
Spinal epidural angiolipoma: MR findings.
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Adult↗
[Loss of psychic autoactivation syndrome: bilateral lacunae of the neostriatum. Clinico-radiological study of 2 cases].
In two patients with lack of spontaneous activity and emotionality, without dementia or depression and in absence of other neurologic signs, the "athymormia syndrome" has been diagnosed. CT scan and MRI showed bilateral symmetrical lesions in basal ganglia. We discuss the possible pathophysiological basis of the syndrome and the recent data about the functional connections among basal ganglia, frontal cortex and limbic system.
Adult↗
Pontine hydatid cyst in association with an acoustic neurinoma: MR appearance in an unusual case.
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Echinococcosis↗
[MRI and HM-PAO SPECT in 20 patients with drug-resistant partial epilepsy].
Twenty consecutive patients with chronic partial seizures with onset before twenty years of age were investigated by means of 0.5 T MRI (20) and HM-PAO (19) in order to identify focal alterations amenable to surgical therapy. MRI evidentiated parenchymal lesions in 7 patients. Findings consistent with unilateral medial temporal sclerosis and cortico-subcortical parietal scars were found in two patients each. Small solid nodular lesions in the temporal lobe were observed in two patients. These and one additional patient with nodular partially cystic lesions in temporal lobe were administered a paramagnetic contrast agent (Gadolinium DPA) intravenously. In one case a contrast enhancement was observed. Histologic examination post surgery revealed a low grade glioma in one patient. HM-PAO SPECT examination showed area of abnormal captation in 9 of 19 patients. Aspects of EEG correlation with the MRI and SPECT findings are discussed. Our data supported the usefulness of magnetic resonance and SPECT imaging in the completion of pre-surgical assessment in this kind of patients.
Adult↗