Biomedical subjects

R S Pozzi-Mucelli

Publications and source records attributed to R S Pozzi-Mucelli.

At least 19 recordsLinked to original sources

PubMed2001

Effects of IV methylprednisolone on brain atrophy in relapsing-remitting MS.

BACKGROUND: IV methylprednisolone (IVMP) has been used to treat relapses in patients with relapsing-remitting (RR) MS, but its effect on disease progression is not known. Furthermore, there are no data on the impact of IVMP on T1 black holes or whole-brain atrophy. OBJECTIVE: To determine the effect of IVMP on MRI measures of the destructive pathology in patients with RR-MS and secondarily to determine the effect of IVMP on disability progression in patients with RR-MS. METHODS: The authors conducted a randomized, controlled, single-blind, phase II clinical trial of IVMP in patients with RR-MS. Eighty-eight patients with RR-MS with baseline Expanded Disability Status Scale (EDSS) scores of < or =5.5 were randomly assigned to regular pulses of IVMP (1 g/day for 5 days with an oral prednisone taper) or IVMP at the same dose schedule only for relapses (IVMP for relapses) and followed without other disease-modifying drug therapy for 5 years. Pulsed IVMP was given every 4 months for 3 years and then every 6 months for the subsequent 2 years. Patients had quantitative cranial MRI scans at study entry and after 5 years and standardized clinical assessments every 4 to 6 months. RESULTS: Eighty-one of 88 patients completed the trial as planned, and treatment was well tolerated. Baseline demographic, clinical, and MRI measures were well matched in the two study arms. Patients on the pulsed IVMP arm received more MP than patients on the control arm of the study (p < 0.0001). Mean change in T1 black hole volume favored pulsed IVMP therapy (+1.3 vs +5.2 mL; p < 0.0001), as did mean change in brain parenchymal volume (+2.6 vs -74.5 mL; p = 0.003). There was no significant difference between treatment arms in the change in T2 volume or annual relapse rate during the study. However, there was significantly more EDSS score worsening in the control group, receiving IVMP only for relapses. There was a 32.2% reduction (p </= 0.0001) in the probability of sustained EDSS score worsening in the pulsed MP arm compared with the relapse treatment arm. At the end of the study, EDSS was better in the pulsed MP group (1.7 vs 3.4; p < 0.0001). Prolonged treatment with pulsed IVMP was safe and well tolerated; only two patients dropped out for toxic side effects over 5 years. CONCLUSIONS: In patients with RR-MS, treatment with pulses of IVMP slows development of T1 black holes, prevents or delays whole-brain atrophy, and prevents or delays disability progression. A phase III study of IVMP pulses is warranted.

Adolescent↗

PubMed2001

MRI techniques and cognitive impairment in the early phase of relapsing-remitting multiple sclerosis.

Correlation studies between various conventional and non-conventional MRI parameters and cognitive impairment in the early stages of multiple sclerosis (MS) are lacking, although it is known that a number of patients with early MS have mild cognitive impairment. Our aim was to explore whether this cognitive impairment is dependent on the extent and severity of the burden of disease, diffuse microscopic brain damage or both. We studied 63 patients with clinically definite relapsing-remitting (RR) MS, duration of disease 1-10 years and Expanded disability status scale scores < or = 5.0. Mean age was 35.4 years, mean duration of disease 5.8 years and median EDSS score 1.5. Neuropsychological performance, psychological function, neurological impairment and disability were assessed. The patients also underwent MRI, including magnetisation-transfer (MT) studies. We quantified the lesion load on T2- and T1-weighted images, the magnetisation transfer ratio (MTR) of normal-appearing brain tissue (NABT) and the brain parenchymal fraction (BPF). No significant difference was found between lesion loads in patients with and without cognitive impairment. In 15 patients (23.8%) with overall cognitive impairment, median BPF and average NABT MTR were significantly lower than those in patients without cognitive impairment (0.868 vs 0.892, P = 0.02 and 28.3 vs 29.7 P = 0.046, respectively). Multiple regression analysis models demonstrated that the only variables independently correlated with cognitive impairment were: BPF (R = 0.89, P = 0.001) and average NABT MTR (R = 0.76, P = 0.012). Our findings support the hypothesis that, cognitive decline in patients with MS, a low disability score and short duration of disease is directly associated with the extent and severity of diffuse brain damage. The loss of brain parenchyma did not correlate with the severity of microscopic damage in the NABT, indicating that the two processes could be distinct in the early stages of the disease.

Adult↗

PubMed2001

A longitudinal study of brain atrophy and cognitive disturbances in the early phase of relapsing-remitting multiple sclerosis.

OBJECTIVE: (a) To establish whether the cognitive decline of the early phase of relapsing-remitting multiple sclerosis depends on the progression of the burden of disease, or on the loss of brain parenchyma, or is influenced by both; (b) to monitor the loss of brain parenchyma in the early phase of the disease; and (c) to examine its possible relation with the progression of physical disability. METHODS: For 2 years 53 patients with clinically definite relapsing-remitting multiple sclerosis with disease duration 1-5 years and expanded disability status scale < or =5.0 at baseline were monitored. The neuropsychological performances, the psychological functioning, the neurological impairment, and the disability have been assessed at baseline and after 2 years. Patients also underwent PD/T2 and T1 weighted brain MRI. T2 and T1 lesion volumes were measured by a semiautomatic technique. Quantification of brain parenchymal volumes was obtained using a highly reproducible computerised interactive program. The relation between cognitive impairment and MRI findings has been investigated by partial correlation and stepwise multiple regression analyses excluding the effects of age, education, anxiety, depression, and total days of steroid use. RESULTS: In the 2 years of the study the mean change for T2 and T1 lesion volumes and brain parenchymal volumes were +1.7 ml (95% confidence interval (95% CI) 1.3-2.2, p=0.005, (29.8%); +0.2 ml, 95% CI 0.15-0.26, p=0.004, (25%); and -32.3 ml, 95% CI 24.2-42.3, p<0.0001, (2.7%), respectively. Overall, 14 patients (26.4%) were judged to be cognitively impaired at baseline and 28 (52.8%) at the end of the follow up. Of the 18 neuropsychological tests and subtests employed in the study, patients with multiple sclerosis failed 5.8 (SD 2.3) tests at the baseline and 8.4 (SD 2.9) (p<0.0001) tests at the end of the study. When the cognitive changes were examined in individual patients, five (9.4%) of them were considered cognitively improved, 33 (62.3%) remained stable, and 15 (28.3%) worsened over 2 years. T2 and T1 volume changes in improved, stable, and worsened patients did not show any significant difference, whereas brain parenchymal volume decrease in cognitively worsened patients was significantly greater (-66 ml (5.4%), 95% CI 37-108.9, p=0.0031). The cognitive impairment was independently predicted over 2 years only by the change of brain parenchymal volumes (R=0.51, p=0.0003). Ten patients (18.9%), who worsened by one or more points in the EDSS during the follow up period had significant decreases in brain parenchymal volumes (-99 ml (8%), 95% CI 47.6-182.3, p=0.005). At the end of the study the loss of brain parenchyma correlated significantly with change in EDSS (r= 0.59, p<0.0001). CONCLUSIONS: In the early phase of relapsing-remitting multiple sclerosis the cognitive deterioration relies more on the development of brain parenchymal volume atrophy than on the extent of burden of disease in the brain. The loss of brain parenchymal volume underlies the progressive accumulation of physical disability from the initial phase of the disease, which becomes more demonstrable only if studied with longer observation periods. Probably, the main pathological substrate of brain atrophy in the early stage of the disease is early axonal loss, which causes the progression of neurological deficits and the development of cognitive impairment. These data support the debated opinion that disease modifying therapy should be initiated as early as possible.

Adult↗

PubMed2000

Short-TE projection reconstruction MR microscopy in the evaluation of articular cartilage thickness.

The aim of this study was to assess the potential of projection-reconstruction (PR) MR microscopy in the accurate measurement of cartilage thickness. Short-TE PR microimages were acquired at 7.05 T on bone-cartilage cylindrical plugs excised from four regions of two disarticulated femoral heads (i. e. superior, inferior, posterior and anterior), using an NMR instrument equipped with a microimaging accessory. The PR microimages were then correlated with conventional spin-echo (SE) microimages and with histology. On PR microimages, acquired with an echo time of 3.2 ms, the cartilage signal was increased, allowing an accurate delineation of the cartilage from the tidemark/cortical bone region. As a consequence, by the PR method a more precise measurement of cartilage thickness compared with that performed by the conventional SE approach was feasible. An excellent correlation between PR microimages and histology was also obtained (r = 0.90). By the proposed method it is possible to accurately determine the cartilage thickness better than with the conventional SE sequences.

Aged↗

PubMed2000

Dynamic magnetic resonance imaging in the assessment of chronic medical nephropathies with impaired renal function.

We examined the value of dynamic magnetic resonance imaging (MRI) in chronic renal disease with renal insufficiency. In 33 consecutive patients (21 vascular nephropathy, 12 glomerular nephropathy) MRI was performed using a 1.5-T unit and a body coil, with SE T1-weighted (TR/TE = 600/19 ms) and dynamic TFFE T1-weighted sequences (TR/TE = 12/5 ms, flip angle = 25 degrees ) after manual bolus injection (via a cubital vein) of 0.1 mmol/kg Gd-DTPA-BMA. Morphological evaluation was performed in unblinded fashion by three radiologists, evaluating renal size, cortical thickness, and corticomedullary differentiation. Functional analysis was performed by one reviewer. Time-signal intensity curves, peak intensity value (P), time to peak intensity (T), and the P/T ratio were obtained at the cortex, medulla, and pyelocaliceal system of each kidney. The relationship of these parameters to serum creatinine and with creatinine clearance was investigated. A good correlation between morphological features of the kidneys and serum creatinine values was found. Morphological findings could not distinguish between vascular and glomerular nephropathies. A statistically significant correlation (P <0.01) between cortical P, cortical P/T, medullary P, and serum creatinine and creatinine clearance was found. A significant correlation (P <0.01) was also found between cortical T, medullary P/T, T of the excretory system, and creatinine clearance. The cortical T value was significantly higher (P <0.01) in vascular nephropathy than in glomerular nephropathy. Thus in patients with chronic renal failure dynamic MRI shows both morphological and functional changes. Morphological changes are correlated with the degree of renal insufficiency and not with the type of nephropathy; the functional changes seem to differ in vascular from glomerular nephropathies.

Aged↗

PubMed1998

Magnetic resonance imaging in a case of Wernicke's encephalopathy.

Wernicke's encephalopathy is an uncommon disorder caused by a thiamine deficiency which is clinically characterized by the triad of ophthalmoplegia, ataxia and disturbances of consciousness, each finding being variably present. The disease is caused by malnutrition or malabsorption, and is often associated with prolonged alcohol intake, neoplasm and extensive inflammatory processes of the digestive tract and parenteral hyperalimentation-induced gastrointestinal mucosal atrophy. Clinical diagnosis can be elusive and MRI may be the only imaging technique able to detect the cerebral lesions, whose type and distribution are characteristic of the Wernicke's encephalopathy, whereas CT is positive only in exceptional cases. We report a case of a 56-year-old woman who developed a Wernicke's encephalopathy 1 month after a colonic resection with signal intensity changes located in the mammillary bodies and in the medial thalamic nuclei.

Brain↗

PubMed1998

Magnetic resonance imaging of articular cartilage: ex vivo study on normal cartilage correlated with magnetic resonance microscopy.

The aims of this study were (a) to compare the MR appearance of normal articular cartilage in ex vivo MR imaging (MRI) and MR microscopy (MRM) images of disarticulated human femoral heads, (b) to evaluate by MRM the topographic variations in articular cartilage of disarticulated human femoral heads, and subsequently, (c) to compare MRM images with histology. Ten disarticulated femoral heads were examined. Magnetic resonance images were obtained using spin-echo (SE) and gradient-echo (GE) sequences. Microimages were acquired on cartilage-bone cylindrical plugs excised from four regions (superior, inferior, anterior, posterior) of one femoral head, using a modified SE sequence. Both MRI and MRM images were obtained before and after a 90 degrees rotation of the specimen, around the axis perpendicular to the examined cartilage surface. Finally, MRM images were correlated with histology. A trilaminar appearance of articular cartilage was observed with MRI and with a greater detail with MRM. A good correlation between MRI and MRM features was demonstrated. Both MRI and MRM showed a loss of the trilaminar cartilage appearance after specimen rotation, with greater evidence on MRM images. Cartilage excised from the four regions of the femoral head showed a different thickness, being thickest in the samples excised from the superior site. The MRM technique confirms the trilaminar MRI appearance of human articular cartilage, showing good correlation with histology. The loss of the trilaminar appearance of articular cartilage induced by specimen rotation suggests that this feature is partially related to the collagen-fiber orientation within the different layers. The MRM technique also shows topographic variations in thickness of human articular cartilage.

Aged↗

PubMed1998

Paraganglioma of the cauda equina: case report and review of the MRI features.

We report a case of paraganglioma of the cauda equina and review the MRI features in 11 previously published cases with MRI description. On T1-weighted images, paraganglioma is isointense relative to spinal cord and shows moderate to intense enhancement after Gd-DTPA application, usually with heterogeneous texture. On T2-weighted images, different findings were found. MRI features do not allow to distinguish paraganglioma of the cauda equina from majority of other tumors in this region.

Cauda Equina↗

PubMed1997

Assessment of pituitary microadenomas: comparison between 2D and 3D MR sequences.

The aim of this study was to compare the diagnostic value and image quality of two different T1-weighted MR sequences in the evaluation of PRL-secreting pituitary microadenomas. Twenty-four patients with a clinical diagnosis of pituitary microprolactinoma were prospectively examined with both a 2D SE and a 3D turbo-SE T1-weighted coronal sequence, before and after intravenous contrast medium administration. Evaluation of MR images was done only on postcontrast images and considered the number of slices in which the lesions were visible and image quality, which was evaluated by both a subjective score and objective parameters (signal-to-noise and contrast-to-noise ratios). Pituitary microprolactinomas are visible in a higher number of slices in 3D TSE sequences; the subjective scores for image quality and signal-to-noise ratios were similar in both 2D and 3D sequences; the contrast-to-noise ratio was always higher in 3D sequences. In patients with hyperprolactinemia, the authors recommend using coronal 3D TSE T1-weighted sequences for evaluation of the pituitary region. 2D SE T1-weighted sequences may be considered if a shorter examination time is required (i.e., for claustrophobic patients) and in assessment or follow-up of microadenomas when a larger size lesion is clinically suspected.

Adult↗

PubMed1997

MRI appearance of the articular cartilage in the knee according to age.

To study the MR appearance of knee joint hyaline cartilage according to age, sex and body weight 120 subjects underwent MRI of the knee. Axial SE PD and T2, GE T1 and GE-MTC sequences, as well as coronal SE T1 and sagittal SE PD and T2 sequences were used. Thickness, surface, signal intensity and visibility of the patellar and femorotibial cartilages were investigated. As for cartilage thickness, a statistically significant difference was found between males and females in nearly all the measurement sites, the mean values being always higher in males. A statistically significant inverse correlation was found in males only, at the three load bearing regions of the medial femoral condyle. No significant correlation was demonstrated between the surface, the signal intensity and the trilaminar appearance of the cartilage and age, as well as body weight. The cartilage of the femoral condyles, the tibial plateaux and the patella showed a regular surface in 76%, 98% and 82% of cases respectively. The signal intensity was homogeneous in 88%, 98% and 82.5% of the cases. Mild focal inhomogeneities were seen in few cases. The visibility rate of the trilaminar appearance of cartilage was 85% for the femoral condyles, 70% for the patella, 13.5% for the tibial plateaux. GE sequence was the best sequence to evaluate cartilage thickness and signal intensity, while SE T2 sequence was the best sequence to depict the articular surface and, together with PD SE sequence, to visualize the trilaminar structure. The most relevant result of this study is the inverse correlation between cartilage thickness and age as well as body weight, mainly in males, in the three areas of greatest load (medial femoral condyle).

Adolescent↗

PubMed1996

Investigation of laminar appearance of articular cartilage by means of magnetic resonance microscopy.

Magnetic resonance (MR) images and relaxation and diffusion maps of articular cartilage were obtained to explain discrepancies in its MR appearance. Porcine specimens were studied only by MR microscopy. For human specimens a combination of MR microscopy and large-scale MR imaging was used. Common features in the laminar structures of human and porcine samples are described. It was found that the decay of transverse magnetization was nonexponential with a rapidly decaying component which prevented construction of reliable proton-density maps. Dependence of T2 values on the orientation of specimens in the magnetic field as well as magnetization transfer experiments supported the previous suggestions about a significant role of dipolar interaction with protons of collagen in the laminar appearance of articular cartilage. The loss of the laminar structure induced by rotation of the human cartilage specimen around the axis normal to its surface demonstrated nonuniform angular distribution of the collagen fibers within the layer.

Animals↗

PubMed1996

CT and MRI findings after stereotactic resection of brain lesions.

OBJECTIVE: To describe postoperative CT and MRI findings and their time course in uncomplicated cases after stereotactic volumetric resections of brain lesions. MATERIALS AND METHODS: One-hundred twenty-eight imaging studies (CT, 86; MRI, 42), performed 6 h to 2 years after 52 stereotactic operations, were retrospectively reviewed and analyzed in relation to time of surgery in cases without complications. RESULTS: The extent of resection bed did not change during the first week after operation; reduction of size then began and continued up to 3-6 months. Mass effect and edema showed no changed during the first 4 days, then later regressed gradually. Pneumocephalus was found in 58% of cases in the first 3 weeks, but never later. Benign, surgically-induced enhancement appeared at the margins of encephalotomy and retractor at the end of the first postoperative week, became more prominent during the following weeks, and lasted up to 3-5 months. In the majority of cases enhancement prevented recognition of the residual tumor. Dural enhancement was observed at the craniotomy site very early after the operation and persisted up to 1 year. Meningeal enhancement over convexities was found in 44% of MRI studies. CONCLUSION: Extent of the resection bed, mass effect, edema, and pneumocephalus show, in uncomplicated cases, a regular regression during the postoperative period. The time course of enhancement is complex and can be a source of diagnostic misinterpretation.

Brain↗

PubMed1995

Delayed CT findings in acute renal infection.

The computed tomography (CT) findings in twelve patients with acute renal infection examined immediately and 3 h after i.v. contrast medium are reported. Three patients also had delayed scans at 6 h. Three main features were observed on the delayed scans: 1 a delayed nephrogram with streaky, wedge shaped or round high density areas. The areas of high density were at the same sites of the inhomogeneous areas of reduced density on the early scans; 2 focal contrast medium staining or a rim of increased density around abscesses; 3 focal areas of increased density at sites distant from the low density areas seen on the early scans. It is postulated that the delayed areas of increased density replace early areas of reduced density caused by ischemia due to vasospasm and/or compressing oedema of the vascular bed or by tubular obstruction. Delayed CT appears to be useful because it improves diagnostic confidence and gives a more exact evaluation of the extent of infection.

Acute Disease↗

PubMed1993

[Renal angiomyolipomas: atypical aspects in ultrasonography and computerized tomography].

As a rule, renal angiomyolipomas (AML) present with characteristic patterns on US and CT images. However, in a limited number of cases US and CT findings are atypical, so that no diagnosis can be made on their basis. The authors reviewed their personal series of renal tumors and now report the US and CT findings of 5 cases with atypical features on one or both examinations. Two patients had hyperechoic lesions with typical AML patterns, but no fatty densities were visible with CT. Both patients underwent surgery and histology which showed two AMLs with muscular and vascular components and very few fatty cells. Two cases were observed in patients with Bourneville disease. Even though the cases exhibited atypical features on US and CT images, the diagnosis was suspected on the basis of the well-known association of tuberous sclerosis with AML. One case presented with a complex cystic mass on US; CT showed a bleeding tumor. Even though no unquestionable diagnosis of AML could be made in this case, the hypothesis of a bleeding AML was considered in the differential diagnosis. Such atypical imaging features were related to low fatty content inside the lesion and to bleeding complications. Absent/low fatty component represented a cause of atypical lesion appearance on CT which showed a mass with soft-tissue density which could not be differentiated from a solid tumor. In these cases, AMLs remained typically hyperechoic on US images. Bleeding represented a cause of error mainly on US since the typical hyperechoic pattern was replaced by a iso-hypoechoic pattern. CT is helpful in these cases because it shows both the bleeding and possible low-density fatty areas.

Adult↗

PubMed1992

Idiopathic anterior hypopituitarism: magnetic resonance imaging and clinical correlation.

We describe the anatomical abnormalities in the hypothalamic-pituitary region revealed by magnetic resonance imaging (MRI) in 10 patients, 8 men and 2 women, affected by idiopathic anterior hypopituitarism (IAH). In all cases contiguous sagittal and coronal T-1 weighted images were obtained. In 9 patients the high-intensity posterior lobe was missing, in almost all patients the pituitary stalk was thin and/or transected, and in 8 a bright T-1 nodule was detected at the infundibular apex, near the tuber cinereum, in the median eminence. None had diabetes insipidus. MRI proves to be very useful in understanding the etiopathogenesis of IAH.

Adult↗

PubMed1992

Computed tomography and magnetic resonance imaging in diagnosing hepatocellular carcinoma.

The evaluation of hepatocellular carcinoma (HCC) is based upon ultrasonography (US) which has proved to have a high sensitivity and is also extremely useful in guiding the percutaneous needle biopsy. The main role of computed tomography (CT) and magnetic resonance imaging (MRI) is to supplement US in evaluating the extent of HCC. The Authors discuss the different techniques of examinations of the liver both for CT and MRI as far as the modalities of contrast enhancement, site of injection, and type of contrast agents are concerned. The differences between low field and high field magnets are also discussed. The main CT and MRI findings are illustrated, depending upon the technique of examination. Finally the role of these techniques is discussed. Based upon personal experience and the data in CT literature, and if performed with updated technology and intraarterial injection (lipiodol), CT is the method of choice in order to supplement US in the evaluation of HCC.

Carcinoma, Hepatocellular↗

PubMed1992

[Magnetic resonance in trigeminal neuralgia].

One of the possible causes of the so-called "essential" trigeminal neuralgia is a neurovascular compression of the fifth cranial nerve root at the pons. The demonstration of this hypothesis could orientate the surgical treatment to microvascular decompression. In order to evaluate the role of MRI in the diagnosis of trigeminal neuralgia due to neurovascular compression, the authors present the results of a prospective evaluation of the cranial MR studies of 18 neuralgic patients in comparison with a retrospective evaluation of the cranial MR studies of 50 healthy control subjects. The results show that neurovascular compression can be demonstrated in 83.3% of the neurological patients. In all cases a good correlation between the clinical symptoms, the side of positive MR findings and the surgical findings, when available, was demonstrated. On the other hand, neurovascular compression was demonstrated in 28% of the healthy control subjects. The authors conclude that neurovascular compression can be demonstrated in a high percentage of patients with the so-called "essential" trigeminal neuralgia. Compared with the other imaging modalities (angiography, Computed Tomography) MRI is the best technique in the diagnosis of this disease. In fact, MRI is not only able to differentiate the symptomatic from the essential type of neuralgia, but is also very sensitive in the identification of trigeminal neuralgia due to neurovascular compression. This diagnosis could direct the surgical treatment to microvascular decompression.

Adolescent↗

PubMed1990

Cystic renal tumors: US and CT findings.

Cystic renal tumors represent a variety of lesions in which both solid and liquid components coexist. These lesions may be either benign or malignant and include the multilocular cystic nephroma (MCN), the renal cell carcinoma (RCC), and the papillary adenocarcinoma (PAC). The MCN is a rare neoplasm formed of multiple loculated cystic masses divided by septa. The tumor is benign, although there are some rare reports of malignant cases. The RCC and the PAC may appear with cystic patterns. This is rather uncommon for the RCC, which inside has a unilocular or multilocular cystic appearance, if the necrotic component is large. PAC is an infrequent renal tumor, which has a greater tendency to appear as a large mass with a unilocular large cystic space. The ultrasonography (US) and computed tomographic (CT) features of 27 cystic tumors are presented. Both US and CT allowed the recognition of the cystic components, the septa, and the vegetations. The two imaging techniques made it possible to distinguish the tumors into "unilocular" and "multilocular" masses: the former correspond to RCC and PAC, the latter to MCN and RCC. CT added some information on calcified or partially calcified tumors. CT more than US enabled the differentiation between the malignant RCC and the benign MCN for which conservative surgery may be indicated. The two techniques did not allow the differentiation between RCC and PAC, which has different prognostic behavior.

Adenocarcinoma, Papillary↗