PubMed Health⌕ Search

Biomedical subjects

L Landoni

Publications and source records attributed to L Landoni.

At least 19 recordsLinked to original sources
PubMed2006

A case of intraductal papillary mucinous tumour following recurrent attacks of pancreatitis lasting 26 years.

We report an interesting case of a patient with neither family nor personal history for pancreatic diseases that was admitted to our department in 1982, at the age of 25 years. At that time, medical history, absence of alcohol abuse, and radiological imaging suggested a diagnosis of idiopathic chronic pancreatitis. The patient underwent a left-pancreatectomy, with histological confirmation of chronic pancreatitis. He was asymptomatic until 1988, when episodes of pain arose, requiring a pancreatico-jejunostomy. No further problems ensued until 2004 when radiological investigation following pain-related symptoms revealed enormous dilation of the pancreatic duct. A pylorus-preserving pancreaticoduodenectomy resulting in total pancreatectomy was performed. Histological examination revealed an intraductal papillary mucinous non-invasive carcinoma. Review of the previously resected specimen revealed former misdiagnosis. This tumour usually affects an elderly population and nowadays is recognised as a possible cause of chronic obstructive pancreatitis. This report represents a slippery case of misdiagnosis and demonstrates that follow-up is always mandatory following a diagnosis of idiopathic chronic pancreatitis.

Adenocarcinoma, Mucinous↗
PubMed2003

Treatment of six hepatic artery aneurysms.

Hepatic artery aneurysms are rare lesions but of significant clinical importance because rupture is associated with elevated mortality. Although diagnosis using CT scanning and, more importantly, angiography has been well defined, the therapeutic choices are less clear. We retrospectively selected patients from 1985 to 2000 who were treated with either traditional surgical or percutaneous techniques. In total we treated six patients, four males and two females. This represents 17.6% of 34 patients treated by us for splanchnic artery aneurysms. The treatment was surgical in two cases (33.3%) and percutaneous in four cases (66.6%). All lesions were successfully treated with exclusion/ablation of the aneurysm. Mortality was nil; in one of the surgical cases we reported a transient hepatic failure and in the endovascular group, one right pleural effusion, one small splenic infarction, and one pseudoaneurysm of the gastroduodenal artery. The first therapeutic strategy to be taken into consideration is always the percutaneous approach. However, surgery still has a role in those cases where the lesion cannot be repaired percutaneously. Based on our own experience (good results, no mortality, and few complications) and in accordance with the literature, it is clear that an aggressive approach is warranted in those patients.

Aged↗
PubMed1996

Human quadriceps cross-sectional area, torque and neural activation during 6 months strength training.

Quadriceps muscle and fibre cross-sectional areas (CSA), torque and neural activation were studied in seven healthy males during 6 months of weight training on alternate days with six series of eight unilateral leg extensions at 80% of one repetition maximum. After training, the quadriceps cross-sectional area increased by 18.8 +/- 7.2% (P < 0.001) and 19.3 +/- 6.7% (P < 0.001) in the distal and proximal regions respectively, and by 13.0 +/- 7.2% (P < 0.001) in the central region of the muscle. Hypertrophy was significantly different between and within the four constituents of the quadriceps. Biopsies of the vastus lateralis at mid-thigh did not show any increase in mean fibre cross-sectional area. Maximum isometric voluntary torque increased by 29.6 +/- 7.9%-21.1 +/- 8.6% (P < 0.01-0.05) between 100 degrees and 160 degrees of knee extension, but no change in the optimum angle (110 degrees-120 degrees) for torque generation was found. A 12.0 +/- 10.8% (P < 0.02) increase in torque per unit area together with a right shift in the IEMG-torque relation and no change in maximum IEMG were observed. Time to peak isometric torque decreased by 45.8% (P < 0.03) but no change in time to maximum IEMG was observed. In conclusion, strength training of the quadriceps results in a variable hypertrophy of its components without affecting its angle-torque relation. The increase in torque per unit area, in the absence of changes in IEMG, may indicate changes in muscle architecture. An increase in muscle-tendon stiffness may account for the decrease in time to peak torque.

Adult↗
PubMed1992

Assessment of human knee extensor muscles stress from in vivo physiological cross-sectional area and strength measurements.

The physiological cross-sectional areas (CSAp) of the vastus lateralis (VL), vastus intermedius (VI), vastus medialis (VM) and rectus femoris (RF) were obtained, in vivo, from the reconstructed muscle volumes, angles of pennation and distance between tendons of six healthy male volunteers by nuclear magnetic resonance imaging (MRI). In all subjects, the isometric maximum voluntary contraction strength (MVC) was measured at the optimum angle at which peak force occurred. The MVC developed at the ankle was 746.0 (SD 141.8) N and its tendon component (Ft), given by a mechanical advantage of 0.117 (SD 0.010), was 6.367 (SD 1.113) kN. To calculate the force acting along the fibres (Ff) of each muscle, Ft was divided by the cosine of the angle of pennation and multiplied for (CSAp.sigma CSAp-1), where sigma CSAp was the sum of CSAp of the four muscles. The resulting Ff values of VL, VI, VM and RF were: 1.452 (SD 0.531) kN, 1.997 (SD 0.187) kN, 1.914 (SD 0.827) kN, and 1.601 (SD 0.306) kN, respectively. The stress of each muscle was obtained by dividing these forces for the respective CSAp which was: 6.24 x 10(-3) (SD 2.54 x 10(-3)) m2 for VL, 8.35 x 10(-3) (SD 1.17 x 10(-3)) m2 for VI, 6.80 x 10(-3) (SD 2.66 x 10(-3)) m2 for VM and 6.62 x 10(-3) (SD 1.21 x 10(-3)) m2 for RF. The mean value of stress of VL, VI, VM and RF was 250 (SD 19) kN m-2; this value is in good agreement with data on animal muscle and those on human parallel-fibred muscle.

Adult↗
PubMed1991

Quality control in the conservative treatment of breast cancer: patient dosimetry using silicon detectors.

Twenty patients with early breast cancer were treated with external irradiation, delivered with two tangential beams (6 MV X-rays) using a half-beam block (HBB) and 3-D compensating filters. All patients were immobilized with individualized cellulose acetate casts. Patient dosimetry was performed using p-type silicon detectors. Midline doses were calculated by combined entrance and exit dose measurements. The mean ratio of the measured and the prescribed doses was 96.6 +/- 3.8% at the reference point, 96.8 +/- 4.3% at off-axis points on the central plane and 96.8 +/- 7.6% at off-plane points.

Breast Neoplasms↗
PubMed1990

[Personalized low-melting alloy shield for high-energy electrons in the treatment of superficial neoplasms of critical or esthetically important regions].

Individualized Cerrobend beam shapings for high-energy electrons have been utilized in the treatment of superficial tumours located in aesthetic or critical regions. Individualized cellulose acetate masks have been used as immobilization device. Measured transmissions through Cerrobend ranged from 0.5% at 4 MeV to 8.5% at 18 MeV. Phantom dosimetry showed a poor influence of Cerrobend on PDD (percentage depth doses). Output factor variations appeared to depend on electron energy and shielded area. It is very important to perform either empirical measurements or to adopt semiempirical models in order to exactly calculate those output factors. Three clinical examples are presented: the utilization of immobilization device and field shaping are illustrated with the main aim of sparing the dose to critical organs.

Electrons↗
PubMed1990

[Verification of 3 computerized systems for drafting a plan for treatment with electrons].

The electron beam treatment planning systems, with the availability of more and more developed hardware for complex calculation algorithms, need quality controls of accuracy and comparability of treatment plans from different systems. In this paper three systems have been evaluated; their similar computation algorithms (pencil beam) have been used but in some conditions (beam reconstruction, oblique incidence and dishomogeneity) different results have been drawn. The basic data (PDD, dose profile, etc.) were the same for every system, therefore it has been observed that different results are mainly due to differences in: a) input of parameter values, b) calculation algorithm approximations, c) image acquisitions and elaboration.

Electrons↗
PubMed1989

Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps.

Four male subjects aged 23-34 years were studied during 60 days of unilateral strength training and 40 days of detraining. Training was carried out four times a week and consisted of six series of ten maximal isokinetic knee extensions at an angular velocity of 2.09 rad.s-1. At the start and at every 20th day of training and detraining, isometric maximal voluntary contraction (MVC), integrated electromyographic activity (iEMG) and quadriceps muscle cross-sectional area (CSA) assessed at seven fractions of femur length (Lf), by nuclear magnetic resonance imaging, were measured on both trained (T) and untrained (UT) legs. Isokinetic torques at 30 degrees before full knee extension were measured before and at the end of training at: 0, 1.05, 2.09, 3.14, 4.19, 5.24 rad.s-1. After 60 days T leg CSA had increased by 8.5% +/- 1.4% (mean +/- SEM, n = 4, p less than 0.001), iEMG by 42.4% +/- 16.5% (p less than 0.01) and MVC by 20.8% +/- 5.4% (p less than 0.01). Changes during detraining had a similar time course to those of training. No changes in UT leg CSA were observed while iEMG and MVC increased by 24.8% +/- 10% (N.S.) and 8.7% +/- 4.3% (N.S.), respectively. The increase in quadriceps muscle CSA was maximal at 2/10 Lf (12.0% +/- 1.5%, p less than 0.01) and minimal, proximally to the knee, at 8/10 Lf (3.5% +/- 1.2%, N.S.). Preferential hypertrophy of the vastus medialis and intermedius muscles compared to those of the rectus femoris and lateralis muscles was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Force of knee extensor and flexor muscles and cross-sectional area determined by nuclear magnetic resonance imaging.

The maximal strengths of knee extensor (E) and flexor (F) muscles were compared in a group of 6 male subjects aged 24-31 years. Cross-sectional area (CSA) of E and F was evaluated from planimetric measurements of Nuclear Magnetic Resonance (NMR) imaging axial scans, carried out at five levels along the thigh. Maximal CSA for E was found at 2/3 upper femur height and at 1/3 lower femur height for F. Maximum isometric force (MIF) of E was found to be 135% greater than that of F. The maximum CSA of E was found to be 93% larger than CSA of F. The calculated mechanical advantage of the flexors was estimated to be 13.8% higher than that of the knee extensors (0.116 +/- 0.012 and 0.132 +/- 0.005, respectively). However, when MIF of E and F were standardised for their respective CSA, no significant difference was found between their stress: 80.1 +/- 15.5 N.cm-2 for E and 70.5 +/- 7.0 N.cm-2 for F. From the present study, it is concluded that no significant difference exists between the maximum stress of knee extensor and flexor muscles despite large differences in their absolute values of force and CSA and that the NMR imaging technique enables accurate in-vivo determination of the CSA of individual muscles.

Adult↗
PubMed1988

[Magnetic resonance of the thoracic aorta].

Various pathological conditions of the thoracic aorta were studied by MR Imaging in 31 patients: 23 were aneurysms (branching and non-branching), 2 arterio-venous fistulae, 2 aortic prostheses, 2 Marfan's syndromes, 1 coronary sinus aneurysm, and 1 isthmic stenosis. MRI studies were always performed on patients who had been examined by other imaging procedures. A comparative study was carried out on the results of MRI, angiography, computerized tomography, and ultrasounds. The possibility of propedeutic protocol was explored. Our experience, in accordance with the literature on the subject, indicates MRI as the procedure of choice in the study of aneurysms of the thoracic aorta. The advantages offered by MRI--the high natural contrast between circulating blood and the supporting structures, the possibility of obtaining multiplanar images as well as data on intraluminal, parietal, and extraparietal conditions--make it a highly competitive procedure if compared to either CT or angiography. While awaiting further evidence, the use of a propedeutic protocol in non-aneurysmatic diseases is still not advisable, due to insufficient patient population, and to the lack of a consistent literature on the subject.

Adult↗
PubMed1987

Magnetic resonance diagnosis of intramedullary tumors of the spinal cord.

Fifty patients with intramedullary space occupying lesions were studied with MR from October 1983. Of these 32 were operated on and histological diagnosis together with gross morphological description was available. MR findings were reviewed in search for morphological and signal characteristics capable of providing a better preoperative diagnosis. There were 11 astrocytomas, 10 ependymomas, 5 vascular lesions and 6 "gliomas". All lesions usually had signal characteristics different from those of the normal cord, mainly because of prolonged T1 and T2 relaxation times. No specific patterns related either to morphology or signal were found, capable of differentiating the two main histological types. Vascular malformations may be suspected from the presence of serpiginous areas without signal. Tumor nodules within cysts can however be well recognized, thus providing the neurosurgeon with very useful preoperative information. Some characteristics of signal and morphology, are more common for one or the other of the two main groups of tumors. A tumor involving all the cord with a homogeneously prolonged T2 relaxation time is most likely to be an astrocytoma. A small nodule with signal close to normal parenchyma, associated with extensive cysts, is most likely to be an ependymoma.

Adult↗
PubMed1986

Magnetic resonance in multiple sclerosis.

Magnetic Resonance Imaging was performed in more than 200 patients with clinical suspicion or knowledge of Multiple Sclerosis. One hundred and forty-seven (60 males and 87 females) had MR evidence of multiple sclerosis lesions. The MR signal of demyelinating plaques characteristically has prolonged T1 and T2 relaxation times and the T2-weighted spin-echo sequences are generally superior to the T1-weighted images because the lesions are better visualized as areas of increased signal intensity. MR is also able to detect plaques in the brainstem, cerebellum and within the cervical spinal cord. MR appears to be an important, non-invasive method for the diagnosis of Multiple Sclerosis and has proven to be diagnostically superior to CT, evoked potentials (EP) and CSF examination. In a selected group of 30 patients, with the whole battery of the relevant MS studies, MR was positive in 100%, CT in 33.3%, EP in 56% and CSF examination in 60%. In patients clinically presenting only with signs of spinal cord involvement or optic neuritis or when the clinical presentation is uncertain MR has proven to be a very useful diagnostic tool for diagnosis of MS by demonstrating unsuspected lesions in the cerebral hemispheres.

Female↗
PubMed1986

Magnetic resonance imaging of cerebral cavernous angiomas.

Magnetic resonance imaging (MRI) proved to be far superior to computed tomography and angiography in detecting cavernous angiomas in 55 patients, with a total of 72 lesions. A cavernous angioma usually appears as a nodular lesion with a relatively short T1 and long T2, circumscribed by a hypointense ring. The MR signal varies according to histopathologic components. Usually, no significant mass effect is detected. Sometimes a rim of edema or gliosis is present (long T2). When a massive bleeding is present, differential diagnosis from chronic hematoma of other origin is not always easy, but may be possible from the clinical presentation and some MR findings.

Adolescent↗
PubMed1986

[Cardiac magnetic resonance with electronic axial angulation].

MR usually provides sections in three standard orthogonal plans (axial, sagittal, coronal). In the present research we have studied the possibilities and the benefit of the anatomical images performed along the main cardiac axis, using--beyond the cardiac gating--a particular software which allows to obtain layers with a double angulation, still keeping the patient supine. This provides a more detailed visualization of the cardiac architecture and a good evaluation of its functional conditions.

Evaluation Studies as Topic↗