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Biomedical subjects

G Crespi

Publications and source records attributed to G Crespi.

At least 19 recordsLinked to original sources
PubMed2000

[Ultrasonography features of the diaphragmatic crura: normal anatomy and its variants].

PURPOSE: To report the various US patterns of the diaphragmatic crura and the changes occurring during the different phases of respirations. The diaphragm has two US patterns: the central membranous part appears highly reflective while the posterior, upper and lateral muscular portions are hypoechoic and thick. The crura can sometimes appear quite bulky, which appearance is easy to misinterpret. MATERIAL AND METHODS: We carried out a three-stage work: first we reviewed the US examinations of 23 subjects with a nodular appearance of the posteromedial bundles and studied the changes in thickness during respiration. Second we studied the diaphragmatic crura in 30 subjects aged 18-71 years, 15 men and 15 women. We used a commercially available unit with sector and convex 3.5 MHz probes at baseline and during breath hold and acquired multiple parasagittal and transverse scans. The crura thickness was measured in all patients. Last, we studied the diaphragmatic regions of 10 patients with right pleural effusion and of 8 patients with associated ascites and pleural effusion using 2.0-5.0 MHz convex phased-array transducers. RESULTS: We found focal thickening of the crura in 11 of 23 patients with US findings of diaphragmatic nodules, but only in deep inspiration. The thickening was 1.5-2.2 cm long and maximum thickness was 10 mm. In the other 12 subjects we found 9 small lobules in the right and 3 in the left crus. In the anatomic study, we observed a 3-band appearance of the diaphragmatic crura, probably referable to muscle bundles, in 30 subjects on sagittal images, in 12 on coronal images and in 28 on anterior transverse images. The diaphragmatic crura were identified in 26 subjects only. The left posterior crus was identified in 29 subjects on left coronal images and in 15 on anterior transverse images; it was demonstrated on anterior sagittal images in close proximity to the aorta in only 4 subjects. Right crus thickness, measured on sagittal scans, ranged 3-10 mm in deep inspiration and 1-4 mm in expiration while the left crus was 3-6 mm in inspiration and 1-2 mm in expiration. The length of the right crus, studied in the preaortic portion, ranged from 7 cm in deep inspiration to 9.7 cm in expiration while the left one was 6.5 to 8.8 cm. The right lateral diaphragmatic bundles were seen in 28 subjects only on repeated subcostal oblique scans and the the left ones in 11 subjects only. Finally the thin anterior bundles were shown on parasagittal images in 13 cases in the right side and in 2 in the left. A 2-band appearance of the diaphragm was seen in 10 patients with pleural effusion and in 8 patients with associated ascites. A single band was found only in the tendinous portion of the diaphragm. DISCUSSION AND CONCLUSIONS: US is presently considered the imaging method of choice in the assessment of changes in thickness and length of the diaphragmatic crura. These structures have different US patterns and can sometimes appear quite bulky and thus be easily mistaken for other anatomic or abnormal structures; orthogonal scans may be required for the differential diagnosis.

Adolescent↗
PubMed1999

Determination of substances of abuse in biological fluids by GC/MS using chemical ionization with acetonitrile.

GC/ms is an important method to determine drugs in biological fluids. For each of the most commonly used drugs a methanolic solution (100 micrograms/ml) was prepared; 30 microliters of each solution was evaporated using nitrogen flow and than diluted in 100 microliters of a derivatizing mixture constituted by MSTFA and toluene (30/70). After a short reaction time at room temperature 1 ml of each solution was injected into a SE-52 column (15 m x 0.25 mm) using chemical ionization with acetonitrile. This method has a good signal/noise ratio and is very useful in screening techniques.

Acetonitriles↗
PubMed1998

Duplex Doppler analysis of interlobular arteries in transplanted kidneys.

The aim of our study was to analyze changes in spectral Doppler waveforms between interlobar and interlobular arteries in renal transplants and to determine whether sampling location at interlobular level can be suitable for intrarenal resistive index (RI) measurements. Paired series of spectral tracings from interlobar arteries and respective interlobular branches were obtained in 62 consecutive renal transplants at 6.5-MHz Doppler frequency. The values of peak systolic velocity (PSV), end diastolic velocity (EDV) and RI were significantly (P < 0.01) reduced when calculated at interlobular level. In 38 % of cases, an interlobar RI higher than 0.70 corresponded to a normal interlobular RI. The values of PSV, EDV, and RI did not differ significantly at interlobular level between allograft subsets with normal and elevated serum creatinine level. Both intra- and interobserver variation were higher at interlobular than at interlobar level when performing the RI. During a conventional study of renal vasculature, an underestimation of abnormal RI findings can be expected from the incidental evaluation of interlobular tracings. We recommend sonologists to pay attention in accurately locating the sample volume at interlobar-arcuate level when evaluating intrarenal RI.

Adult↗
PubMed1998

Power Doppler sonography: clinical applications.

OBJECTIVE: Color Doppler imaging (CD) has had a great impact on ultrasonography (US). This technique depicts local flow by encoding an estimate of the mean Doppler frequency shift at a particular position in color. However, the choice of the mean frequency shift as the parameter for representing flow in color Doppler is somewhat arbitrary. Power Doppler ultrasound is a technique that encodes the power in the Doppler signal in color. This parameter is fundamentally different from the mean frequency shift. The frequency is determined by the velocity of the red blood cells, while the power depends on the amount of blood present. Providing an image of a different property of blood flow, power Doppler has shown several key advantages over colour Doppler, including higher sensitivity to flow, better edge definition and depiction of continuity of flow. In this paper we review the results of power Doppler clinical studies. MATERIALS AND METHODS: All relevant information available in the literature on the potential clinical applications of this technique was revised to give a detailed survey. RESULTS: The increased flow sensitivity and better vascular detailing of power Doppler have been used to detect flow presence and characteristics in vessels that are poorly imaged with conventional color Doppler. The improved depiction of tissue vasculature has shown potential advantages, especially in some areas, such as the cortex of native kidneys and renal allografts, the prepuberal testis, the infant hip and the bowel wall, in which color Doppler is not sensitive enough to detect clinically important, slow and poor flow in small vessels. In inflammatory conditions, power Doppler was valuable in depicting increased flow in vessels that are dilated because of inflammatory response. In this field, advantages have been reported in acute cholecystitis and in inflammatory states of musculoskeletal tissues. The higher sensitivity to slow flow and the improved detailing of the course of tortuous and irregular vessels made power Doppler a promising technique to image intratumoral vessels and, thereby, to ameliorate the accuracy of color Doppler in predicting the likelihood of benign versus malignant nature of nodules. Specific flow patterns, missed at color Doppler studies, have been indicated with power Doppler in some tumors of the liver and breast. In different settings, power Doppler also permitted to monitor serial blood flow changes after therapy and to display them as color intensity, allowing the observer to distinguish flow changes. CONCLUSION: Although the actual role of power Doppler in changing patient management has not been assessed yet, this technique can depict flow which was previously undetectable, and thus permits an easier and more confident diagnosis in body regions where the ultrasound signal is weak because blood vessels are small.

Blood Vessels↗
PubMed1998

[Neuroleptanalgesia in patients undergoing percutaneous, ultrasound-directed radiofrequency for primary or secondary, single or multiple hepatic neoplasms].

BACKGROUND: The use of percutaneous ultrasound-directed radiofrequency is a recent technique in non-surgical therapy of some neoplastic liver lesions. Purpose of this study is to demonstrate that the use of a narcosis-free analgesia allows to perform this procedure, which is generally painful and badly by the patient. METHODS: We treated 51 patients for a total of 126 procedures; the first 17 patients underwent a mono- or multipolar technique with uncooled electrodes, while the remaining 34 patients have been treated with double perfusion lumen electrodes with the chance of tipcooling. We used diidrobenzoperydol and fentanyl with a mean dose for each session of 209 micrograms for the first 17 patients and 109 micrograms for the other 34. RESULTS: Using VAS, we obtained a painless procedure in 42 patients and mild-pain sensations in 9 patients, while one hour after the procedure painless or light-pain sensation were observed in 49 patients and mild-pain in 2 patients, which required the use of FANS i.v. At discharge, all patients were pain-free or with very light pain sensation. We reduced the intra-hospital observation of patients from 5 to 3 hours, once the technique has been modified. 4 patients complained about nausea and 1 of these emesis. We did not observe any cardiovascular, respiratory and/or neurological complications. CONCLUSIONS: The use of neuroleptanalgesia allowed us to perform the described procedure with a good feeling by the patients.

Aged↗
PubMed1997

Response to clozapine in acute mania is more rapid than that of chlorpromazine.

The purpose of the present study was to compare the efficacy of clozapine with that of chlorpromazine in an open label manner (both given in association with lithium salts) in the treatment of acute mania. Thirty hospitalized manic patients were entered into the study. All patients met DSM-IV criteria for bipolar disorder, Manic Episode; 27 patients completed the study and three patients dropped for noncompliance. The duration of the study was 3 weeks. Patients were randomly assigned to two treatment groups; group 1 (n = 15) was treated with clozapine at a mean dose of 166 mg/day and group 2 (n = 12) was treated with chlorpromazine at a mean dose of 310 mg/day. Manic symptomatology was rated on Young Rating Scale for Mania (YRSM) each week; side effects were recorded on dosage records and treatment emergent symptoms; extrapyramidal acute side effects were rated on the Simpson-Angus Rating Scale performed at the beginning of the study and after 3 weeks of treatment. A two-way repeated measures analysis of variance on YRMS scores showed a significant time effect (p < 0.0001) and a significant time-group interaction (p < 0.0001). Post-hoc comparison between the two groups showed a significant difference after 2 weeks of treatment (p = 0.0001), with clozapine treated patients showing lower YRSM scores than chlorpromazine treated patients. YRSM scores at the end of the study were not significantly different. Patients treated with clozapine showed a more rapid trend toward amelioration. No clinically relevant side effect was observed during the study.

Acute Disease↗
PubMed1997

Superior vena cava stents: Doppler US of the internal mammary veins to detect collateral flow--preliminary observations.

In 12 patients with superior vena cava syndrome secondary to malignant disease, duplex Doppler ultrasound (US) was performed in the internal mammary veins. In all patients, flow was retrograde. After stent placement, flow direction was again antegrade on one side (17%) or both sides (83%). During follow-up in the internal mammary veins, blood flow remained unchanged in 10 patients and retrograde flow recurred in two patients at 2 and 5 months, respectively. In these two patients, helical computed tomography showed stent failure. Successful treatment in one patient normalized the direction of flow in the internal mammary vein. Doppler US in the internal mammary veins allowed accurate evaluation of function of superior vena cava stents.

Collateral Circulation↗
PubMed1996

Hemangiopericytoma of the greater omentum: US and CT appearance.

The US, Doppler and CT appearances in a patient with hemangiopericytoma of the greater omentum are presented. Ultrasound revealed a solid mass with heterogeneous echo pattern, well-defined margins and marked vascularity with low impedance flow (mean resistive index 0.42). The tumour was mobile. It was detected below the left kidney at the first US examination and had migrated into the pelvis 14 days later. At CT the tumour demonstrated strong but brief peripheral enhancement and a central hypodense scar.

Adult↗
PubMed1996

Interlobular vasculature in renal transplants: a power Doppler US study with MR correlation.

PURPOSE: To evaluate, with power Doppler (PD) ultrasound (US), the normal interlobular vasculature in patients who underwent renal transplantation and to assess if defects of the PD signal at the interlobular level correspond to cortical areas that lack blood perfusion at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Thirty-two normal and 33 malfunctioning transplanted kidneys were studied with PD US (6.5 MHz). PD images of interlobular vessels were graded on a scale of normal (pattern I) and decreasing visualization. In kidneys with focal (pattern II) and diffuse (pattern III) absence of interlobular signal, correlative dynamic MR imaging was performed. RESULTS: Interlobular vessels were consistently depicted with PD US in the proximal cortex of normally functioning transplanted kidneys. Of kidneys with a pattern II appearance, five had no contrast material enhancement in the cortical sites in which the interlobular PD signal was detected and three were contrast enhanced but it was less intense than that in adjacent cortical sites with normal interlobular vasculature. All transplanted kidneys with a pattern III appearance had delayed contrast enhancement. CONCLUSIONS: Although PD US appears to depict the interlobular vasculature up to the renal capsule, care should be taken in the diagnosis of perfusion defects, since absence of detectable flow at the interlobular level does not always correspond to cortical areas that lack perfusion on MR images.

Adult↗
PubMed1996

Lipomatous tumors of the uterus: ultrasonographic findings in 11 cases.

We reviewed the ultrasonographic findings in eight patients with 11 lipomatous uterine tumors studied with transabdominal (eight cases) and transvaginal (six cases) techniques. A transvaginal color Doppler study was obtained in five patients. Two patients had more than one nodule (two and three uterine nodules, respectively). All lipomatous tumors had regular margins and were hyperechoic. Transvaginal sonography allowed the identification of one small previously undetected tumor but was not able to image the entire extent of two large lipomatous masses. In one case, it helped to establish the actual uterine origin of an eccentric pelvic mass. Color Doppler sonography showed complete absence of flow in all tumors examined. We believe that lipomatous tumors of the uterus can be diagnosed with a high degree of certainty by ultrasonography if a homogeneously hyperechoic avascular mass can be clearly identified to be of uterine origin.

Adult↗
PubMed1994

Efficacy of SH U 508 A (Levovist) in color Doppler ultrasonography of hepatocellular carcinoma vascularization.

To assess the efficacy of a new US contrast agent [SH U 508 A (Levovist), Schering] in evaluating hepatocellular carcinoma (HCC) vascularization, 38 patients with 43 lesions were submitted to color Doppler US before and after i.v. contrast medium administration. Four patients were studied after arterial chemoembolization. The patients had been selected on the basis of suboptimal color Doppler signals on baseline images. Each patient received two to four injections of Levovist in standard doses. Tumor vascularization was qualitatively graded on a 0-3 scale. Twelve tumors (27.9%) appeared avascular at baseline examinations, while 31 (72.1%) exhibited low to moderate flow signals. After contrast agent administration, color Doppler signals were markedly enhanced in 35/43 lesions (81.4%), lasting 40 to 240 seconds. The lack of enhancement was related to tumor hypovascularity (necrosis at CT), portal vein thrombosis, deep location and successful chemoembolization. The detection of flow signals in chemoembolized tumors was explained by the persistence of viable tumor tissue. After Levovist administration, flow signals were detectable in 97.6% of the HCCs. Therefore, Levovist proved to be an effective tool for color Doppler evaluation of HCC vascularization.

Carcinoma, Hepatocellular↗
PubMed1992

Sonographic detection of renal changes in pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a rare hereditary disease whose basic abnormality is degeneration of elastic tissue, with calcification of the tonaca media of the arteries, and typical yellowish papules of the skin. We report the sonographic findings observed in a young patient with PXE at the level of the kidneys: fine hyperechogenic spots suggesting small calcifications were diffuse at the corticomedullary junction; however, normal waveforms were obtained at the level of intraparenchymal renal vessels. The presence of this structural pattern in a young patient with dermatologic abnormalities should lead to the consideration of PXE in the differential diagnosis list.

Adult↗
PubMed1992

[Artifacts in echo-Doppler and color-Doppler].

It is well known that artifacts can be observed during US examinations; the same is true also for Doppler and color-Doppler images of blood flow. Recognizing these artifacts is important to avoid image misinterpretations and, when possible, to overcome them by modifying either techniques or unit settings, or both. This work was aimed at presenting the several artifacts which can be observed during Doppler investigations, at classifying them, and trying to understand the physical and/or technical principles underlying their origin. Doppler and color-Doppler artifacts can be divided into four large groups: 1) artifacts regarding evaluation of the presence of flow; 2) artifacts regarding evaluation of the direction of flow; 3) artifacts regarding determination of the velocity of flow; 4) artifacts affecting spatial location, on the screen, of the examined vessel. Each of the above can cause severe diagnostic misinterpretations, if not correctly recognized and interpreted. It must be kept in mind that an accurate analysis of unit settings during scanning, and the meticulous evaluation of the obtained color images are of the utmost importance for the proper use of this valuable but difficult diagnostic technique.

Artifacts↗