Multidetector row CT coronary angiography: technique and preliminary experience.

PURPOSE: To report our preliminary experience with multi-slice spiral CT coronary angiography of the coronary arteries. MATERIALS AND METHODS: 50 volunteers (mean age 61 years, range 45-72) with baseline heart rates below 70 bpm underwent multi-detector row CT coronary angiography (GE Light Speed Plus, 140 kVp, 270 mA, 1.25-mm collimation, 0.5-second rotation time, high quality pitch) with retrospective ECG gating after receiving 140-150 ml of iodinated contrast medium (Iopamiro 300 mg-dl, Bracco, Italy) at a flow rate of 4 ml/sec. Three of the 50 patients had previously undergone coronary procedures (1 anterior descending artery stent, 1 left circumflex artery stent and 1 anterior descending artery percutaneous angioplasty) and three were undergoing follow-up examinations after by-pass surgery. The remaining 44 patients were asymptomatic and had no history of coronary artery disease. All CT angiograms were back-reconstructed from 20 to 80% of the diastolic cycle with 10% increments to establish the phase with fewer "stair-step" motion artefacts for each artery. Patients with heart rates above 70 bpm were administered beta-blockers during the five days preceding the examination in doses appropriate for the patient's clinical characteristics. RESULTS: The CT room occupation time ranged from 25 to 35 minutes (mean time 27') and the post-processing time from 30 to 60 minutes (mean time 40'). The left anterior descending artery was best visualised in middle diastole (70% of cardiac cycle), the circumflex artery at 60% of the cardiac cycle, and the right coronary artery at 40%. Out of 132 arteries, 19 (14.4%) were considered non-assessable due to "stair-step" motion artefacts, whereas 2 (1.5%) were only partially visualised owing to the presence of extensive wall calcifications. Among the 113 assessable arteries, we observed: 72 normal coronary arteries without stenosis or wall calcifications (54.5%); 28 arteries with minimal wall irregularities and stenoses below 50% (21.2%); 7 stenoses >50% involving the right coronary artery (no. 2), the anterior descending arteries (no. 4) and the left circumflex artery (no. 1) (5.3%). In the remaining 6 patients, optimal visualisation of the stents and venous and arterial surgical by-passes was obtained. CONCLUSIONS: Although further larger-scale studies are required to compare MSCT coronary angiography with CT coronary angiography, the application of MSCT technology to the study of the coronary arteries is a promising technique with a good potential for use in routine clinical practice. In selected patients (with baseline heart rates <70 bpm, or after beta-blocker therapy) it is able to provide very interesting results and could be used as a method of choice for following patients after interventional procedures or as a mass-screening tool to select patients to be referred for coronary angiography.

[Embolization of the uterine artery in the treatment of uterine myoma]. / Embolizzazione delle arterie uterine nel trattamento dei miomi dell'utero.

PURPOSE: To propose uterine myoma embolization as an alternative to myomectomy or hysterectomy in the treatment of symptomatic myomas; to evaluate the efficacy of the procedure in terms of clinical outcome, adopting all procedural and technical precautions to ensure minimal X-ray exposure and preserve reproductive potential. MATERIAL AND METHODS: Between April 1998 and February 2000, 26 patients, age range 32-54 years (mean 41 years), underwent uterine arterial embolization for menorrhagia, pelvic pain, and sensation of mass and pressure. Inclusion criteria were: single myomas, intramural localization and rich vascolarization of the lesion. Dose to patient was obtained by placing a thermoluminescent dosimeter (Harshaw, Solon, Ohio) both placed in posterior fornix of the vagina and on the skin at the beam entrance site. The procedure was performed under peridural anesthesia; polyvinil alcohol particles 355-500 mu (Contour) (Target Therapeutics, Boston Scientific Corporation, Fremont CA, USA) were employed as embolic agent. The uterine arteries were incannulated with a 5F (Glidecath, Terumo, Europe NV, Belgium) and successively 3F coaxial microcatheter (Target, Boston Scientific Corporation, Fremont CA, USA); the embolic material was injected as distally as possible. Color Power Doppler Ultrasound follow-up before and after i.v. contrast media administration (Levovist SHU 508 A, Shering, Berlin, Germany) was carried out at 15 days, at 1, at 3, at 6 months, and at 1 year from embolization. Pre-procedural evaluation and follow-up at 1 year was performed by MRI using T1 and T2 weighted images before and after Gadolinium (GdDTPA Shering, Berlin, Germany) administration. RESULTS: The technical success of the interventional procedure was 100% (26/26 cases). The mean fluoroscopy time was 20 minutes, and the mean number of angiographic exposures was 10. The mean estimated ovarian dose was 18.75 cGy and the mean adsorbed skin dose was 126.71 cGy. The imaging follow-up showed a 55% reduction of myoma volume at 6 months and a 75% reduction at 1 year. All patients reported a marked decrease in symptoms. No major complications were observed. The appearance of pelvic pain in the 24-48 hours after the procedure required sedation by analgesic pump; transitorial amenorrhea was observed in 3 patients. As for term complications, 2 patients have eliminated necrotic material through the vagina four weeks after procedure. The patients reported great satisfaction with the procedure. DISCUSSION: Many treatment options are currently available for symptomatic uterine myomas. One is surgical myomectomy which is associated with increased blood loss, pain and post operative morbidity and requires an additional surgical procedure for fibroma recurrence in 20-25% of patients. Another alternative treatment is hormonal therapy, which drammatically improves symptoms and reduces fibroid size although leiomyomas regrow to their original size within a few months of discontinuing treatment. Uterine embolization is a relatively new treatment for uterine fibroids that can be considered as an alternative to surgical and medical procedures. The radiation exposure adsorbed by the patient is reduced by using pulsed fluoroscopy and taking all the precautionary measures required to minimize the dose. CONCLUSIONS: The technical success, the patient' satisfation, the short hospitalization time and preservation of fertility confer to uterine artery embolization the role of a new alternative therapy for the treatment of symptomatic uterine myomas.

[Non-invasive assessment of epiaortic vessels. Comparison of magnetic resonance angiography with gadolinium, spiral computerized tomography angiography, and digital angiography]. / Valutazione non invasiva dei vasi epiaortici. Confronto tra angiografia con Risonanza Magnetica con gadolinio, angiografia con tomografia Computerizzata spirale e angiografia digitale.

PURPOSE: The aim of the study was to compare gadolinium-enhanced MRA (Gd-MRA), Computed Tomography angiography (CTA) and digital subtraction angiography (DSA) in the evaluation of carotid stenosis. MATERIAL AND METHODS: Thirty patients with US-proven internal carotid artery stenosis over 50%, underwent Gd-MRA, CTA and DSA. Gd-MRA was acquired using the keyhole technique. RESULTS: The overall agreement was 90% for Gd-MRA and 93% for CTA. Gd-MRA and CTA overestimated 5 and 4 cases of mild stenosis and 1 case each of moderate stenosis, respectively. Gd-MRA better delineated ulcerated plaques, tandem lesions and pseudo-occlusions. DISCUSSION AND CONCLUSIONS: Because of the high speed acquisition breath-hold is no longer necessary for Gd-MRA and more delayed phases were analysed when necessary. The main limitation of Gd-MRA was represented by insufficient volume coverage that allowed the visualisation of supraaortic vessels from the arch only in 57% of the cases. Calcified plaques were very well detected by CTA and not by Gd-MRA. In our experience Gd-MRA represents the second step non invasive tool in patients with US-proven carotid stenosis. This leads to avoid conventional angiography in most cases.

[Breath-hold gadolinium enhanced tree-dimensional MR angiography: personal experience in the thoracic-abdominal area]. / L'angiografia con Risonanza Magnetica con gadolinio e sequenza tridimensionale gradient-echo apnea. Esperienza personale nel distretto vascolare toraco-addominale.

PURPOSE: To investigate different clinical applications of gadolinium-enhanced MR angiography (Gd MRA) using three-dimensional breath-hold GE sequences, without bolus time calculation, in patients with vascular diseases. MATERIAL AND METHODS: Forty-seven patients were examined (49 studies in all). Eleven of them had an abdominal aortic aneurysm, 6 surgical bypass, 7 renal artery stenosis, 3 aortoiliac Wallstent, 7 aortic stent-graft; 11 patients had a suspected condition in the thoracic aorta and pulmonary arteries, 1 had subclavian artery stenosis and 1 suspected axillary artery compression. All patients were submitted to breath-hold Gd MRA, after 30-40 mL Gd, with a 1.5 T magnet (Gyroscan ACS-NT, Philips, The Netherlands) and a standard body coil. The GE sequences were acquired with TR = 8.8, TE = 2.7, FA = 60 degrees, matrix = 163 x 512, with 28 seconds acquisition time. Digital subtraction angiography and intraoperative findings were the reference standards to evaluate the results. RESULTS: Thoracopulmonary district: metastatic compression of axillary vessels was found in 1 breast cancer patient; the true and the false lumens and the intimal flap were identified in 2 patients with chronic aortic dissection (Stanford A), and graft patency and complete resolution of the aortic dissection was seen in the patient operated on for acute aortic dissection (Stanford A). The thrombus, lumen, extent and diameter were studied in 2 patients with thoracic aortic aneurysms. Subclavian artery stenosis was demonstrated in 1 patient, which was treated with transluminal angioplasty and stenting. The other 6 patients had normal findings. Abdominal aortic aneurysms (AAA): as for disease extent, breath-hold Gd MRA had 100% sensitivity and specificity compared with surgical findings. Juxtarenal aneurysm extent, which had been missed at DSA, was detected in 1 patient and then confirmed at surgery. Stenosis: comparing DSA and MRA findings in the whole series of patients we had 97.4% agreement (155/159 arteries), that is 76.4% (13/17) arteries) considering only stenoses > 50%. Breath-hold Gd MRA sensitivity and specificity were 100 and 87.5%, respectively, in our 28 stenoses. Bypass, aortoiliac stent, vascular endograft: patency was demonstrated in all the 6 surgical bypass patients, and there was agreement with color Doppler findings in 5 of 6. Breath-hold Gd MRA seems to have no possible applications in the follow-up of percutaneously implanted iliac stents, but we had excellent findings about patency and position of nichel-titanium endografts used for AAA treatment. CONCLUSIONS: We optimized breath-hold 3D MRA without bolus transit time calculation and with high-dose Gd in different clinical vascular conditions. In our opinion, 3D GE sequences can replace DSA in selected cases, providing a fast, accurate and noninvasive examination.

[Diagnostic imaging and interventional therapy in hepatocarcinoma. Multicenter study of 290 cases]. / La diagnostica mediante immagini e la terapia interventistica dell'epatocarcinoma. Studio multicentrico su 290 casi.

We report the results of a multicenter study on the diagnosis and interventional therapy of hepatocellular carcinoma (HCC). The first aim--diagnosis--was to evaluate the sensitivity of 4 imaging techniques, namely ultrasonography (US), Computed Tomography (CT), digital arteriography (DSA) and Lipiodol CT (LCT), in HCC detection. The accuracy of these techniques was also investigated in tumor staging, which is important for treatment planning. Two hundred ninety patients underwent this imaging protocol. The patients were classified by tumor spread into three groups, namely group 1 (single HCCs < 5 cm), group 2 (multifocal HCCs with max. 3 nodules or tumor volume < 80 cc), group 3 (multifocal HCCs with more than 3 nodules and/or tumor volume > 80 cc). US and CT diagnosed more cases as group 1 and fewer cases as group 3 than DSA and LCT; the latter two techniques gave a similar classification. With LCT as the gold standard, US and CT understaged 27.9% and 26.5% of cases, respectively. Even though LCT is known to have 53% sensitivity, it is currently the most sensitive preoperative investigation and therefore the best tool for treatment planning. In surgical patients, however, intraoperative US, with its nearly 100% sensitivity, is suggested. The second aim--treatment--consisted in assessing the therapeutic efficacy of intraarterial chemoembolization (CEAT) versus percutaneous ethanol injection (PEI) in non advanced HCC and of CEAT versus no treatment (NT) in advanced HCC. Treatment efficacy was evaluated with the following randomized protocols: PEI versus CEAT in group 1, PEI versus CEAT in group 2 and CEAT versus NT in group 3. The data were analyzed relative to 215 patients for 6 to 30 months. The Kaplan-Meier method was used to calculate survival rates, which were, at 24 and 30 months, 72% and 72% for PEI and 72% and 52% for CEAT in group 1, 52% and 28% for PEI and 70% and 50% for CEAT in group 2 and finally 30% and 20% for NT and 45% and 30% for CEAT in group 3. In group 1, PEI appeared markedly superior to CEAT. In group 2, the difference between PEI and CEAT was not statistically significant; the results in this group indicate that CEAT should be considered when three nodules are present because of PEI invasiveness in these cases. In group 3, CEAT results were definitely better in the first two years, but there was no difference with NT patients at the end of the third year. Therefore, CEAT is indicated in advanced HCC because it improves the survival rate in the first 24 months. After this period, the survival time is not modified by treatment.

[Description and preliminary clinical assessment of a digital chest radiographic system with selenium detector (Thoravision)]. / Descrizione e valutazione clinica preliminare di un sistema radiografico digitale del torace con rivelatore al selenio (Thoravision).

The authors describe an innovative digital chest imaging system (Thoravision, Philips Medical System) based on a selenium detector directly converting X-rays in electric charges detectable by electrometers, amplified and digitalized to be sent to the imaging processor. The study was performed on a series of up to 7000 digital chest X-ray examinations and a sample of 173 cases was selected on the basis of particular diseases and pathologic patterns. In the latter case, digital and conventional radiographic techniques were compared. According to this analysis, the digital system was slightly superior in detecting anatomical details, small pleural effusions (3 cases) and slight low contrast interstitial pathologic changes, mainly in apical (12 cases) and retrocardiac (19 cases) lung areas. The conventional screen-film system better showed small hilar calcifications (2 cases). From the protection viewpoint, at equivalent entrance doses, .15-.26. Gy/cm2 of dose-area product (DAP) values were reported with the digital system, using a tension of 150 kV in orthogonal projections, which are considerably lower than .25-.70 Gy/cm2 measured with the conventional technique. Moreover, Thoravision permitted to perform up to 100 exposures/hour, using a phantom, and 15-20 digital chest examinations/hour, versus the average 12-15 with the conventional screen-film system. The initial results are very encouraging from the clinical and cost-effectiveness viewpoints, thanks to higher Thoravision productivity and to exam optimization, even though wider and prolonged experience plus a careful study of diagnostic accuracy, sensitivity and specificity in each group of chest conditions is advisable, to assess the real innovative impact of this digital chest imaging system.

[Treatment of intrahepatic arteriovenous fistula after biopsy. Results in 5 chemoembolization candidates with hepatocarcinoma]. / Trattamento delle fistole artero venose intraepatiche post bioptiche. Risultati in 5 pazienti con epatocarcinoma candidati a chemioembolizzazione.

We report our experience in the treatment of post-bioptic intrahepatic arterioportal fistulas (HAPF) in 5 patients with hepatocellular carcinoma (HCC) treated February, 1993, to May, 1995. In this retrospective study, we reviewed the imaging findings and clinical records of 3 men and 2 women (age range: 49-71 years) with HCC previously diagnosed with US, CT and biopsy. HAPF was detected by angiography (DSA) performed before chemoembolization (TACE). All HAPFs were referrable to biopsy (14-gauge Thru-Cut needle) and were treated with platinum coils positioned through coaxial catheters. TACE was performed immediately after or within a week of HAPF embolization. Therapeutic response after TACE was assessed on the basis of clinical and CT findings, while HAPF embolization success was assessed on the basis of DSA and color Doppler US findings. Reembolization was required in two patients--7 maneuvers in all in 5 patients. Complete HAPF occlusion was demonstrated in 4 patients during color Doppler follow-up and immediately after and at 13 and 24 months (in 2 patients) at DSA. Two of 5 patients died, one because of liver failure after 15 months' follow-up and the other because of complications related to liver transplantation at 11 months' follow-up. Of the extant 3 patients, one underwent liver transplantation and was followed-up for 25 months, while the other two are alive after 24 and 13 months, respectively. Our experience demonstrates that HAPF embolization in HCC patients is really useful for hemodynamic redistribution before TACE and to avoid further HAPF progression.

[Bi- and tridimensional reconstruction with spiral computerized tomography in esophageal neoplasms. Preliminary clinical applications]. / Ricostruzioni bi e tridimensionali con Tomografia Computerizzata spirale nelle neoplasie dell'esofago. Applicazioni cliniche preliminari.

Spiral CT allows rapid data acquisition in an entire anatomical region during a single breath-hold and permits to obtain 2D and 3D reconstructions with good diagnostic accuracy. We investigated the capabilities of spiral CT reconstructions in demonstrating esophageal cancers. Spiral CT was performed in 10 patients with esophageal cancers and in 3 patients who underwent endoprostheses placement with surgical or interventional procedures. Bidimensional (MPR, CPR, MIP) and three-dimensional reconstructions with Shaded Surface Display (SSD) were obtained at the end of each exam. In the analysis of the results, CT reconstructions were compared with previous barium esophagography. Some of the main semiologic patterns were considered: tumor visualization, longitudinal extent of the neoplasm and its relationships with adjacent structures. MPRs were obtained in 9 patients and allowed to visualize the esophageal lumen with a filling defect, the neoplastic mass and its longitudinal and extraluminal extent. SSD reconstructions was obtained in 7 patients and allowed a good assessment of longitudinal neoplasm extent in 6 patients. Neoplastic mass visualization and extraluminal tumor extent were difficult to assess in all cases. MIP reconstructions were obtained in all patients and demonstrated longitudinal neoplasm extent with good accuracy. Neo-plastic tissue was visualized only indirectly through the filling defect of the esophageal lumen. MIP allowed to define, in 5 patients, the relationships of the neoplasms with adjacent vascular structures after the intravenous administration of contrast agent. In conclusion, we consider that Spiral CT reconstructions can be useful for a more accurate staging of esophageal cancers.

Palliative treatment of neoplastic strictures by self-expanding nitinol Strecker stent.

The purpose of this study was to evaluate technical and clinical results of self-expanding esophageal stent implanted in patients with malignant esophageal strictures and clinically significant dysphagia. From June 1992 to September 1994, 27 patients with inoperable tumors of the esophagus or gastric cardiac were treated by placement of 37 self-expanding nitinol stents. Water-soluble contrast and endoscopy studies were performed after the procedure and during the follow-up period. Successful stenting of the stricture was achieved in 27 patients. The mean dysphagia grade dropped from 2.3 to 1 (SD +/- 0.54) immediately after the procedure. After the insertion of the stent, 16 patients died in a period of time ranging from 0 to 13 months (mean 5.6 months), whereas at the end of the study 11 patients were alive 4-15 months after the procedure (mean 8.3 months). No major complications were observed. The results of this study are encouraging because esophageal stent placement was technically easy and clinically effective.

[Aneurysmal disease. Initial clinical experience with spiral computerized tomography angiography]. / Patologia aneurismatica. Esperienza clinica iniziale con angiografia con tomografia computerizzata spirale.

This study was aimed to assess the comparative capabilities of CT angiography (CTA) and DSA in diagnosing aneurysms in different sites in a series of 20 patients. Volumes were measured during intravenous contrast agent infusion and images were then edited and reformatted as 2D and 3D displays (MPR, SSD, MIP techniques). Some of the main semiologic patterns of aneurysms were considered and the diagnostic accuracy of the 3 reconstruction techniques was assessed and compared with that of axial CT and DSA. Abdominal aortic aneurysms were analyzed separately to study the involvement of main collateral vessels. The best results were obtained with MIP and MPR in the assessment of aneurysm extent and neck. MPR is the only technique which could depict the thrombus and the best technique to demonstrate the relationships between aneurysm and adjacent structures. The MIP technique depicts calcifications and is the method of choice to demonstrate the involvement of collateral vessels by abdominal aortic aneurysms. SSD permits good assessment of the neck and of the longitudinal extent of the aneurysms but is severely limited in the analysis of the other variables.

Mammography with synchrotron radiation.

PURPOSE: To determine the feasibility of using synchrotron radiation (SR) in diagnostic mammography. MATERIALS AND METHODS: Monochromatic SR of x-ray beams of selected energies of 14-20 keV were used to obtain mammograms of surgically removed breast specimens that contained tumor nodules. For comparison, conventional mammograms of the same specimens were also obtained. RESULTS: The mammograms obtained with SR had higher contrast and better resolution than did traditional mammograms and demonstrated excellent detail in all cases studied. The mean glandular doses at 17 and 18 keV were 1.56 and 0.83 mGy, respectively, which is compatible with the mean value of 1.41 mGy delivered with the conventional grid apparatus. CONCLUSION: SR mammography appears to be a promising diagnostic imaging technique.

[Palliative treatment of esophageal neoplastic stenoses with self-expanding metallic stents]. / Trattamento palliativo delle stenosi neoplastiche esofagee con stent metallico autoespandibile.

Thirty Strecker nickel-titanium self-expanding metallic stents were implanted in 20 patients with esophageal strictures and inoperable neoplasms in the Departments of Radiology of the University School of Medicine of Ferrara, Genoa, Novara and Rome, from March 1992 to April 1993; follow-up ranged 1 to 13 months. Thanks to the stents, esophageal strictures could be dilated, significantly reducing dysphagia and allowing the patients to return on to a solid diet. Radiological and endoscopic exams proved the efficacy of the stents in all but 2 patients in whom the tumors had invaded the stent lumen and caused obstruction. In all cases the stents were highly biocompatible and well tolerated. Neither major complications, such as perforation or bleeding, were observed, nor minor ones, such as fever or migration from the site of implant, which may occur with plastic prostheses. To conclude, self-expanding metallic stents used in clinical trials for 13 months proved an effective method in the palliative treatment of malignant esophageal strictures.

[Angiography with magnetic resonance in the study of portal hypertension. Clinical applications]. / Angiografia con risonanza magnetica nello studio della ipertensione portale. Applicazioni cliniche.

The role of MR angiography (MRA) was investigated in 31 patients with portal hypertension. The 2D time-of-flight (TOF) technique was used. All patients underwent CT first. MR angiograms were compared with DSA images in 15 cases and to duplex or color Doppler US scans in 16 cases. In 5 low-grade portal hypertension cases MRA showed splenoportal trunk enlargement and portal vein verticalization. In 26 patients with high-grade portal hypertension MRA allowed portosystemic shunts extent to be evaluated. Portal flow reduction or inversion and left gastric vein enlargement were always demonstrated by MRA in the patients with esophageal varices and azygos vein enlargement. MRA always correctly visualized cavernoma (5 cases) and portal vein thrombosis (9 cases). The diagnostic yield of MRA was greater than that of CT and SE MR sequences in 91% of cases. MRA provided the same information as (or more than) DSA and duplex US in 66% of cases.

[Vascular radiology and physics of fluids]. / Radiologia vascolare e fisica dei fluidi.

In the cardiovascular system, morphology and functionality are closely related. The observation that atherosclerotic lesions appear with different incidence in the various sites and prefer bifurcations, suggested that vascular architecture might be an important pathogenic factor. Vascular geometry deals with the evaluation of the "form" element from a theoretical point of a view, pointing out the angles and diameters which can make the arterial system physiologically more efficient. The key element of the system is the bifurcation: depending on whether bifurcations are considered as a single entity or as a whole, either "local" or "global" geometry is employed. The morphology of the bifurcation directly affects blood flow patterns, influencing both blood flow velocity and wall shear stress. Experimental studies evidenced that high blood flow velocities and low wall shear stress have, respectively, a preventive or favorable role in atheroma development. By observing these altered flow sites, the areas which are most likely to develop atherosclerotic damage have been detected in the various bifurcations; the areas correspond to angiographic and autoptic findings. Based on their experience, the authors discuss the contribution that the different imaging techniques can give to the study of vascular geometry.

Computed tomography detection of gastrointestinal neoplasms.

Gastrointestinal (GI) tract neoplasms can be detected, evaluated and staged by computed tomography (CT), especially from high-resolution examinations, but routine CT scanning may occasionally discover GI neoplasms in patients with non-specific symptoms. We therefore evaluated the sensitivity and main signs of CT examinations resulting from routine sessions. In 46 out of 1560 patients who underwent abdominal CT, it was possible to obtain a diagnosis of primitive gastric or colo-rectal tumour by means of barium X-ray and/or endoscopy. The sensitivity rate of CT obtained from the present study was 86% in gastric tumours and 87% in colonic tumours. In gastric lymphoma, infiltrating carcinoma of stomach and rectal carcinoma, the sensitivity rate was 100%. The CT diagnosis of GI neoplasms was based on diffuse or local thickening of the gut on a solid dishomogenous mass showing contrast enhancement. The prevalence of various patterns depends on site of origin and on macroscopic features of the neoplasia. In conclusion the results suggest that abdominal CT, even if performed with a method not specifically devoted to GI tract, has high sensitivity rates and then a high probability of detecting GI neoplasms when unsuspected at time of the examination. In our series 11% of GI neoplasms were initially diagnosed by routine CT examination.

[The use of the single-pulse RARE sequence in the study of the cerebrospinal axis]. / Uso della sequenza "RARE" a singola eccitazione nello studio dell'asse cerebrospinale.

The authors describe a fast MR sequence allowing to obtain a myelographic-like, markedly T2-weighted, image quite similar to conventional myelographies. Relative to conventional spin-echo sequences, in which echoes are encoded so as to achieve the same phase, each echo of the sequence here employed is given a different phase encoding. The sequence, called MYUR (myelography-urography) is based on the generation, after a 90 degrees pulse, of a "train" of 256 echoes, each one phase-encoded differently, by multiple 180 degrees pulses, producing a single image. The total duration of such a sequence, with 2 repetitions, is 21 seconds. The MR myelographic sequence allows to univocally study tissues with a very long T2 relaxation time; under normal conditions, only cerebrospinal fluid, urine and bile are demonstrated. A resistive MR unit operating at 0.28 T was employed in the present study. MR myelography is capable of pointing out an eventual dural sac compression or a space-occupying mass, thus allowing an effective scout-view to center the subsequent pulse sequences; all MR-myelographic exams need to be completed with other short and long TR sequences.

[Synchrotron radiation: a new source in x-ray mammography]. / La luce del sincrotrone: una nuova sorgente nella mammografia con raggi X.

This work was aimed at evaluating the image quality obtainable in X-ray mammography using synchrotron radiation monochromatic lines. After a short review of the current mammographic techniques, the main features of synchroton radiation in the X-ray field are analyzed, especially of that emitted by the Adone storage ring. Its features are then compared with the radiation emitted by a Coolidge tube. The experimental unit used in this study, including beamline, monochromator and mammograph, is then described together with the experimental method for carrying out a series of experiments in the mammographic field employing both monochromatic lines (E = 17 keV) and white radiation from conventional sources. The first series of experiments is described, which employed standard phantoms: the dependence of resolution and contrast on both wavelength and thickness of breast specimens is reported. Several mammograms of neoplastic breast specimens were obtained after mastectomy: they were acquired using both synchrotron monochromatic lines and radiation emitted by a conventional tube and employing the same acquisition system. The comparison of the two series of images shows that synchrotron radiation can demonstrate a high number of anatomopathologic details with high definition, contrast and resolution which cannot be obtained by means of a conventional source. Our results appear very promising and suggest synchrotron radiation as the major tool in the early diagnosis of neoplastic breast lesions.

[The stenotic-occlusive anatomy and pathology of the renal arteries. Their evaluation by magnetic resonance angiography]. / Anatomia e patologia steno-occlusiva delle arterie renali. Valutazione con angiografia a risonanza magnetica.

Magnetic resonance angiography of the renal arteries was performed in 10 healthy subjects, 10 patients with renal artery stenosis and 2 patients with accessory renal artery (1 unilateral, 1 bilateral). All patients selected among 35 subjects with suspected renovascular hypertension had previously undergone digital subtraction angiography. Four patients were studied before and after percutaneous transluminal angioplasty. MRA was performed with time-of-flight technique, with 2D and 3D FISP and 2D FLASH gradient-echo sequences. Digital subtraction angiography demonstrated stenoses ranging 40% to 90% in 10 cases, 7 unilateral (1 transplanted kidney) and 3 bilateral. RA correctly depicted > 90% stenoses in 5 cases, between 50% and 90% stenoses in 2 cases and < 50% in 2 cases. Four stenoses were not properly graded (3 over-graded and 1 not visualized because distal to ostium). Diagnostic accuracy was 71% for unilateral stenoses and 66% for bilateral stenoses (overall accuracy 69.2%).