Low-dose phase contrast x-ray medical imaging.

Phase contrast x-ray imaging is a powerful technique for the detection of low-contrast details in weakly absorbing objects. This method is of possible relevance in the field of diagnostic radiology. In fact, imaging low-contrast details within soft tissue does not give satisfactory results in conventional x-ray absorption radiology, mammography being a typical example. Nevertheless, up to now all applications of the phase contrast technique, carried out on thin samples, have required radiation doses substantially higher than those delivered in conventional radiological examinations. To demonstrate the applicability of the method to mammography we produced phase contrast images of objects a few centimetres thick while delivering radiation doses lower than or comparable to doses needed in standard mammographic examinations (typically approximately 1 mGy mean glandular dose (MGD)). We show images of a custom mammographic phantom and of two specimens of human breast tissue obtained at the SYRMEP bending magnet beamline at Elettra, the Trieste synchrotron radiation facility. The introduction of an intensifier screen enabled us to obtain phase contrast images of these thick samples with radiation doses comparable to those used in mammography. Low absorbing details such as 50 microm thick nylon wires or thin calcium deposits (approximately 50 microm) within breast tissue, invisible with conventional techniques, are detected by means of the proposed method. We also find that the use of a bending magnet radiation source relaxes the previously reported requirements on source size for phase contrast imaging. Finally, the consistency of the results has been checked by theoretical simulations carried out for the purposes of this experiment.

Comparison between the efficacy of dimeric and monomeric non-ionic contrast media (iodixanol vs iopromide) in urography in patients with mild to moderate renal insufficiency.

Non-ionic dimers induce less diuresis than non-ionic monomers, resulting in increased opacification of the urinary tract in intravenous (i.v.) urography. This double blind, comparative, randomized, parallel trial compared the efficacy of iodixanol (non-ionic dimer) and iopromide (non-ionic monomer) in 100 patients with mild to moderate renal insufficiency (serum creatinine of 135 to 265 mumol l-1) who underwent i.v. urography. A total dose of 600 mgI kg-1 bw of iodixanol (320 mgI ml-1) or iopromide (300 mgI ml-1) was injected. Radiographs were blindly evaluated by three radiologists who analysed different parameters (renal border visualization, nephrogram density, calyceal filling and density, papillary blush detection, delineation of collecting ducts, renal pelvis opacification, visualization of ureters, bladder density, bladder distention). Densitometric evaluation on the renal pelvis and bladder was also performed. Iodixanol showed better filling and density of the calyces (p = 0.004), more frequent detection of papillary blush (p = 0.003) and better opacification of the renal pelvis (p = 0.006). No significant differences between the two contrast media were found in regard to other parameters. In conclusion, the results confirmed theoretical expectations. The non-ionic dimer iodixanol is to be preferred to a non-ionic monomer such as iopromide in i.v. urography on patients with impaired renal function.

[Prevalence of smoking habits among secondary school students in Benevento]. / Prevalenza dell'abitudine al fumo tra gli studenti di 3. media di Benevento.

The Campania Region has the highest prevalence rate of smokers in Italy and lowest age of initiation. The aim of this study was to evaluate the target age for antismoking health education campaign and the risk factors of becoming a smoker. A total of 5.1% of the students in the 8th grade in Benevento smoked, and 12.1% were considered at risk for this behaviour. The presence of at least one smoking sibling or friend was a mayor risk factor, while smoking was not associated with parents' profession or smoking habits. Smoking habit begins spreading among 11-13 years old children and it increases exponentially later: a great potential for prevention exists because the problem is perceived but most of students are free.

[Patient perception of functional and cosmetic outcome of orthognathic surgery. Retrospective analysis of 45 patients]. / L'opinion des patients sur les conséquences fonctionnelles et esthétiques après chirurgie orthognathique. Etude rétrospective de 45 cas.

INTRODUCTION: Orthognathic surgery is generally indicated for the treatment of maxillo-mandibular deformities. Surgery is performed to repair functional abnormalities, but also has a cosmetic impact. MATERIAL AND METHODS: We conducted a retrospective study of 60 patients who underwent orthognathic surgery in 1996 and 1997 in order to assess patient perception of functional and cosmetic outcome. A questionnaire was sent to all patients one year after their surgery; 45 responded. RESULTS: We noted cosmetic, functional, and psychological changes. Patients considered that the changes were for the better. For functional abnormalities, 88.9% considered their occlusion had improved and 80% their chewing; 73.4% reported psychological improvement stating they had more self-confidence; 97.8% considered their cosmetic aspect had improved. DISCUSSION: This study enabled us to assess patients' perception of surgical outcome. It must be recalled that the patient basically decides to undertake surgery for cosmetic reasons while the surgeon proposes surgery to improve function. The psychological consequences of orthognathic surgery must be taken into account because the impact is considerable.

[Role of the Doppler technique in the differential diagnosis of solid breast nodules. Personal experience]. / Ruolo delle tecniche Doppler nella diagnosi differenziale delle lesioni nodulari solide mammarie. Casistica personale.

The role of Doppler techniques in the differential diagnosis of benign from malignant solid breast lesions remains to be defined; indeed, it is still debated whether the diagnostic findings of Doppler US add further information to mammographic and B-mode US results. We investigated the diagnostic effectiveness of Doppler techniques in the differential diagnosis of breast nodules, especially in a selected group of patients with questionable diagnosis because of atypical morphological features or benign appearance detected in women over 40 years old. Color Doppler studies were performed on 111 breast nodules with solid features at US; 53 vascularized lesions were also studied with duplex Doppler. All the nodules were submitted to biopsy, which demonstrated 6 nonvascularized lesions to be complicated cysts. There were 105 solid breast nodules (65 benign and 40 malignant). Color Doppler US showed vascular signals in 71% of benign nodules, mainly at the periphery. 12% of benign nodules had Doppler signals of malignancy at color Doppler US; 92% of malignant lesions was vascularized, with irregular intratumoral signals in 37% of them. The peak systolic velocity and the resistive index were higher in malignant tumors (p < 0.02); peak systolic velocity changed in malignant lesions according to tumor size (p < 0.01). Color Doppler correctly suspected malignancy in 62% of the nodules with questionable features; conversely, 31% of the nodules with questionable findings and no color Doppler signs of malignancy proved malignant at biopsy. In conclusion, the role of Doppler studies remains currently limited in the differential diagnosis of solid breast lesions.

[Magnetic resonance of tibiotalar and subtalar joints. Normal anatomy]. / Anatomia nella Risonanza Magnetica delle articolazioni tibiotarsica e sottoastragalica.

Fifty-three ankles of 29 normal volunteers were examined with Magnetic Resonance Imaging (MRI) to improve the anatomical MR knowledge of tibiotalar and subtalar joints. The aim of our study was therefore to assess the visibility of articular cartilages, tendons and ligaments of the ankle and to define the best scan plane for their visualization. MR studies were performed with SE T1-weighted sequences on the sagittal, coronal and axial planes. The visibility of articular cartilages was 70.8% for the tibiotalar joint and 56.3% for the subtalar joint. All ankle tendons and four of the eight ankle ligaments considered in our study were assessed, at least on one of the sagittal, coronal or axial planes, with over 70% visibility. The deltoid ligament was detected in 95% of the cases on coronal images, the anterior and the posterior talofibular ligaments were seen respectively in 82% and in 75% of the cases on axial images, while the interosseous ligament was detected in 87.5% of the cases on sagittal images. Our study assessed both the capabilities and the limitations of MRI in the detection of anatomical structures of the tibiotalar and subtalar joints and defined the best scan plane for their visualization.

Effects of a dimeric vs a monomeric nonionic contrast medium on renal function in patients with mild to moderate renal insufficiency: a double-blind, randomized clinical trial.

The efficacy and safety of nonionic dimeric contrast media in subjects with impaired renal function is largely unknown. The present study was aimed at determining the risk of tubular nephrotoxicity in patients with mild to moderate renal insufficiency who underwent intravenous urography (IVU) with the nonionic dimeric contrast agent iodixanol (Visipaque, Nycomed Imaging, Oslo, Norway). In a double-blind protocol 64 patients (55 males; mean age 68.3 years) with serum creatinine between 135 and 265 micromol/l who were to undergo IVU were randomized to receive iodixanol (a nonionic dimer) or iopromide (a nonionic monomer), 600 mg I/kg b. w. Renal function was evaluated before and 1 h, 6 h, 24 h, 48 h and 7 days after IVU with analysis of serum creatinine, urinary enzymes alanylaminopeptidase and N-acetyl-beta-glucosaminidase, and urinary microproteins alpha-1-microglobulin and albumin. Renal function remained stable in both contrast medium groups during the follow-up period. No statistically significant differences were observed between the monomer and the dimer in terms of urinary enzyme and microprotein excretion or serum creatinine. Transient radiocontrast-induced nephropathy developed in 1 patient who had received iodixanol. The administration of the nonionic dimeric contrast medium iodixanol, or of the nonionic monomer iopromide, entailed a low nephrotoxic potential in patients with mild to moderate renal insufficiency undergoing excretory urography.