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M De Maria

Publications and source records attributed to M De Maria.

At least 37 records · Page 2Linked to original sources
PubMed1996

[A quantitative in-vitro analysis of the effects of magnetic fields and radiofrequencies on amino acid metabolism].

The extensive use of magnetic resonance imaging in medical diagnosis needs experimental confirmation of the real biological harmlessness of magnetic fields and radiofrequencies in the imaging process. To date, no unquestionable conclusions have been drawn and experimental results differ in various literature reports. We investigated the effects of radiofrequencies and magnetic fields on the amino acid content of plasma samples from 10 healthy volunteers aged 25 to 30 years; the samples were exposed for 60 minutes to MR fields at 0.5 T with the sequences commonly used in clinical practice. After exposure to magnetic fields, the samples were analyzed with chromatography and the results compared with those of plasma samples not exposed to MR fields. Thirty-four different amino acids were investigated and no significant changes were observed in the total concentration of any of them. Our results show that, at least in a cell-free system, exposure to a magnetic field at 0.5 T causes no significant quantitative changes in amino acid composition, at least no changes demonstrable at chromatography. On the other hand, our preliminary observation does not exclude that exposure to nonionizing radiation may modify in vivo enzyme kinetics with transient qualitative, but not quantitative, changes.

Adult↗
PubMed1996

[Biomechanical correlations of lesions associated with traumatic diseases of the anterior cruciate ligament. Analysis with magnetic resonance].

To investigate the correlations between traumatic injuries of the anterior cruciate ligament and other ligamentous, meniscal and bone traumatic injuries, a series of 193 patients with anterior cruciate ligament injuries studied with MRI between January 1992 and December 1994, was retrospectively reviewed. MR results were compared with arthroscopic and/or surgical findings in most (181) patients; in the remaining 12 patients, clinical follow-up was performed. We used two 0.5 superconductive MR units, with dedicated coils and T1-weighted spin-echo and T2*-weighted gradient-echo sequences on the axial, sagittal and coronal planes. Anterior cruciate ligament injuries were associated with other ligamentous, meniscal and bone injuries in 78% of patients. The patients were classified in 5 groups depending on biomechanics and the association of injuries: -group I: isolated injury of the anterior cruciate ligament (41 patients), most frequently caused by forced extension stress associated with "kissing contusions" of the anterior portion of the lateral femoral condyle and of the lateral tibial plateau; this type of injury is less frequently caused by forced flexion stress associated with avulsion fracture of the tibial eminence; -group II: associated injury of the anterior cruciate ligament and medial compartment (62 patients), caused by forced flexion-external rotation stress (abduction, valgism and external rotation). The classic association of this mechanism was the injury of the anterior cruciate ligament, medial collateral ligament and medial meniscus (O'Donoghue triad) (9 patients). Valgus stress and the pivot-shift phenomenon can impact the tibial and femoral articular surfaces, with consequent osteochondral contusion; -group III: associated injury of the anterior cruciate ligament and lateral compartment (26 patients), caused by forced flexion-internal rotation stress (adduction, varism and internal rotation). This mechanism can cause, as a typical bone lesion, Segond fractures; -group IV: associated injury of the anterior cruciate ligament, lateral and medial compartments observed in 52 patients with different associations of varus-valgus and rotatory stress; -group V: in 5 patients, anterior cruciate ligament injury was associated with traumatic injury of the posterior cruciate ligament; in this case, posterior displacement of the tibia and knee hyperextension were the most common mechanisms of injury. In conclusion, our results demonstrate that anterior cruciate ligament injuries due to traumatic sprains of the knee are rarely isolated (21%). Thus, it is important to know the biomechanics of knee trauma to read MR images in order to detect possibly associated injuries. The final goal is to assess the actual extent of the traumatic damage for best subsequent clinical-therapeutic management.

Adolescent↗
PubMed1996

[Introduction to the study of the Willis circle with transcranial color Doppler: methodological notes and preliminary experience].

To date, adult intracranial circulation has been studied only with pulsed-wave Doppler US, which is a useful diagnostic tool even though several technical and practical limitations are related to the difficult location of intracranial vessels. Recently, dedicated color-Doppler transducers have been proposed, which can pass through the skull which makes a physiologic barrier for the US beam: this technique has been called transcranial color-Doppler (TCD). We report on our personal experience with TCD in 30 healthy volunteers (12 men and 18 women, age range: 17-75 years) submitted to TCD for Willis circle imaging. We used an ATL Ultramark 9HDI unit with a phased array transducer (3.5 MHz) and 2 MHz Doppler frequency; the PRF was 3000 Hz, with 80% color gain. 100 Hz wall filters were used. The middle cerebral artery was always shown correctly in all subjects, while the posterior one was depicted only in 7 cases (23.3%); in contrast, the anterior cerebral artery was demonstrated in 3 cases only (10%). Nowadays, TCD is mostly applied to normal intracranial circle studies, to assess normal blood speed values more accurately. To this purpose, both the direct visualization of blood vessels and the flowmetric values obtained measuring the incidence angle are useful pieces of information. TCD permits a more accurate study of intracranial local blood flow in the Willis circle and of its changes in pathologic conditions. In contrast, TCD yield is poor in characterizing intracranial tumor tissue.

Adult↗
PubMed1995

[Biomechanics and semeiotics of traumatic lesions of the posterior cruciate ligament using magnetic resonance].

The authors reviewed 458 MR examinations of the knee to assess the potentials of this technique in the study of traumatic injuries of the posterior cruciate ligament (PCL) and to investigate the frequency of their association with injuries of other knee joints. MR images were acquired with an 0.5-T super-conductive unit with an extremity coil. T1-weighted spin-echo (SE) and T2*-weighted gradient-echo (GE) sequences were used on sagittal, coronal and, in some cases, axial planes, with 3-mm slice thickness and 0-1 mm slice gap. The following parameters were studied to diagnose partial or complete PCL tears: PCL thickness and outline, disruption of ligamentous fasci and signal intensity features. The injuries were classified as proximal, intermediate and distal according to their site. Thirteen PCL tears were detected, 5 of them complete and 8 partial. Complete tears were found in 4/5 patients in the middle third and one patient had a distal intersection tear with tibial bone avulsion. Partial tears were found in the distal tract in 5/8 patients, in the proximal tract in one patient and in the middle third in 2 patients. In 12/13 patients capsuloligamentous knee tears were associated. Overall MR rate of PCL tears was 2.8%; of them, 92.3% were associated with other capsuloligamentous injuries. MR diagnosis was confirmed at arthroscopy in 12/13 patients. The sagittal plane was best in optimally demonstrating the whole PCL and its injuries. GE T2* sagittal sequences demonstrated the site of PCL tears better than SE sagittal ones. Relative to other authors, we found MRI an extremely reliable method to distinguish partial from complete PCL tears. This was probably due to the thinner slices (3 mm) we used. MRI can accurately assess the extent of traumatic injuries of the PCL and of other capsuloligamentous parts of the knee, which is relevant from the clinical point of view. Indeed, MRI allows useless diagnostic arthroscopy to be avoided and yields major indications to choose the correct treatment.

Adult↗
PubMed1994

[Comparison of echography and magnetic resonance in sprains of the external compartment of the ankle].

In most cases ankle sprains involve external compartment ligaments. In particular, the anterior talofibular ligament is involved alone in 70% of cases and together with calcaneofibular and posterior talofibular ligaments in the remaining 30% of cases. To investigate the potentials and the possible limitations of high-frequency US (7.5-13 MHz) for the preliminary assessment of the extent of damage of the capsulo-ligamentous lesions of the external ankle compartment, 25 athletes with clinical diagnosis of sprain trauma were examined with conventional radiology. Morphology and structure were studied from the semiologic point of view. US findings were compared with MR results. In all patients, US showed anterior talofibular ligament lesions alone in 13 patients and associated with calcaneofibular ligament lesions in 12 patients. The posterior talofibular and the interosseous talocalcaneal ligaments were never demonstrated by US. In 4/13 patients diagnosed by US as having isolated anterior talofibular lesions, MRI demonstrated a coexisting calcaneofibular lesion (4/13) and, in one of them, a posterior talofibular and interosseous talocalcaneal ligaments lesion. The comparison of US and MR findings in the patients US had diagnosed as having associated anterior talofibular and calcaneofibular ligaments lesions, showed 100% agreement; MRI allowed the demonstration of the lesions in the posterior talofibular and interosseous talocalcaneal ligaments in 2/12 patients. Considering the statistical prevalence of the anterior peroneal-astragalic lesions caused by ankle sprains, the use of high-frequency US as the first diagnostic approach seems justified. Nevertheless, MRI is a fundamental complement for accurately assessing damage extent.

Adolescent↗
PubMed1994

[Echo-color Doppler in acute scrotum].

The Authors report their experience about the use of color doppler US in the diagnosis of acute scrotal pain. Their data show the importance and the central role of color Doppler US to distinguish between phlogosis and ischemia.

Acute Disease↗
PubMed1993

[The Nissenkorn endourethral prosthesis: our experience].

The Authors report their experience about 40 patients who presented urinary retention by cervico-prostatic obstruction with anesthetic counterindications or limited life expectancy, cured with the urethral prosthesis of Nissenkorn (IUC). Our data permit to say that in selected patients IUC may represent an effective treatment with minimal invasiveness, low cost and few side effects.

Aged↗
PubMed1993

[Echography in the follow-up of patients receiving an endoscopic injection of teflon for vesico-renal reflux].

The surgical treatment of vesicorenal reflux implies open surgery and consequently an hospitalization. The sub-ureteric injection of poly-tetra-fluoro ethylene (Teflon) for correction of vesicorenal reflux was first utilized in 1981 by Matouschek. We have reviewed our personal experience with endoscopic correction of vesicorenal reflux from 1985 to 1990 and evaluated the importance of ultrasonography especially in the follow up.

Adolescent↗
PubMed1993

[Echo-guided puncture of intraprostatic cysts: our experience].

Prostatic cysts are a pathological condition which is rare and still poorly known. In the past a precise diagnosis was difficult and was made with radiologic examination and/or cystoscopy and/or surgery. Up to date echotomography is the most important technique not only for the diagnosis but also for the treatment of prostatic cysts. The Authors relate upon their experience about diagnosis and treatment of prostatic cysts.

Cysts↗
PubMed1993

[Echographic localization and monitoring of bladder calculi treated with ESWL].

The standard treatments for bladder stones consist either of an open operation or endoscopic transurethral disintegration and extraction. These treatment require anesthesia and hospitalization. We report our experience of ESWL monotherapy in the treatment of 10 patients affected by bladder stones. Our early datas show that ESWL for bladder stones is a safe an effective therapy which can be performed without the use of anesthesia in an outpatient basis.

Adult↗
PubMed1992

[Intrinsic endometriosis of the ureter. Clinical case].

Endometriosis is defined as the presence of endometrial tissue outside the cavity of the uterus. The urinary tract is rarely affected, only 1 to 11%. Bladder is the most frequent urinary localization while the ureteral involvement is rare. We report a case of intrinsic ureteral endometriosis in a woman with left hydronephrosis, lumbar pain and septic fever. Instrumental and laboratory investigations can hardly lead to a reliable diagnosis of ureteral endometriosis. A final diagnosis is feasible only by histologic examination, which obviously implies surgery.

Adult↗
PubMed1992

[Normal anatomy and findings in traumatic pathology of the popliteal system. A MR study].

To date, the lesions of the popliteal system, which are responsible for the so-called postero-lateral knee instability, are still an imperfectly known chapter of knee conditions. We retrospectively analyzed 215 consecutive MR examinations performed May-August 1991 to evaluate MR capabilities in correctly depicting both the normal anatomy and the pathologic conditions of the popliteal system. Using our standard protocols for knee study and two different magnets (0.064 and 0.5 T), we identified 23 lesions of the popliteus and of its meniscal and peritoneal insertions, and 17 lesions involving also other capsular and ligamentous structures of the knee. Coronal T1-weighted images were the best ones to correctly identify normal knee anatomy, whereas sagittal T2-weighted images were more sensitive in detecting popliteal lesions. Our results had clinical or surgical confirmation in all cases.

Humans↗
PubMed1991

[Echography in scrotal trauma].

The Authors report 28 cases of scrotal traumas evaluated during a period of 5 years on an amount of 1.100 scrotal echography: 5 patients with severe scrotal trauma are investigated with echography within 2 hours while the others between 1 and 6 days. Some cases of overlooked trauma were studied some months later. In their experience the authors underline the importance of echography in early diagnosis of scrotal contents lesions which need a surgical exploration and those which allow a medical treatment. Also ultrasound investigation is important in evaluating and in the follow-up the scrotal content lesions caused by trauma.

Biopsy, Needle↗