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L E Derchi

Publications and source records attributed to L E Derchi.

At least 91 records · Page 5Linked to original sources
PubMed1993

Case report: imaging of a bilobed gallbladder.

Imaging of the gallbladder demonstrates a wide range of anatomical variants, including anomalies in location, number and shape. Duplication anomalies are quite rare and are characterized by a large variety of configurations depending on the size and degree of fusion of the two lobes, and on the number and disposition of the cystic ducts. We present a case of a deeply cleft, bilobed gallbladder imaged by computed tomography (CT), ultrasonography (US) and oral cholecystography (OCG). The anomaly consisted of complete duplication of the body and fundus into two distinct and separated lobes both of which entered a single infundibulum. Awareness of congenital gallbladder variants may help in recognizing and correctly classifying gallbladder abnormalities, thus preventing misdiagnoses.

Adult↗
PubMed1993

[Abdominal Doppler echography. Pathologic arterial signals].

In this paper, the features are reported of the major pathological flow signals obtained during Doppler examinations of abdominal vessels. The patterns are correlated with the pathological lesions which may cause them, as well as with the underlying changes in arterial hemodynamics. Pathological flow signals are divided into three groups, according to the sites where the lesions producing them are located. a) Lesions of the vessel walls. In this group, both widening of spectrum due to disturbed flow and increased blood velocity from vessel stenosis are presented. Also flow alterations occurring in aneurysms (reduction of flow velocity and presence of vorticous flow) are discussed. b) Changes in peripheral resistances. Peripheral resistances may either increase or decrease due to a variety of diseases. Parenchymal edema, compression, infiltration, as well as small vessel disease, may increase vascular impedance. Fall of vascular resistances may be observed in inflammation or in arteriovenous fistulas either large (congenital or hemodialysis fistulas) or microscopic, as in many hypervascular tumors. A typical "to and fro" flow pattern was seen in vessels where flow resistance is overcome only during systole, such as in arterial pseudoaneurysms. c) Changes in rhythm or strength of the heartbeat, cardiac valvular diseases, postocclusive flow. A variety of pathological findings may be observed in these conditions. Peculiar changes in the waveforms are seen with variations in heart frequency. Changes may be detected also in aortic valvular diseases, with retrograde flow observed in patients with aortic insufficiency. Low and slow flow are seen in post-stenotic and/or postocclusive vessels.

Abdomen↗
PubMed1992

Sonographic diagnosis of obstructed afferent loop.

We reviewed the sonographic findings in four patients with afferent loop obstruction from tumor of the gastric stump. All had undergone partial gastrectomy with Billroth type II gastrojejunostomy. The obstructed afferent loop was visible in all cases as a distended fluid-filled segment with multi-layered wall and few mucosal folds. Its course could be traced from the region of the hepatic hilum to the gastric stump. In two patients, the relationships between the loop and the mesenteric vessels, aorta and inferior vena cava allowed us to recognize it as postoperative duodenum. Thickening of the gastric remnant and obstructive jaundice were diagnosed in three cases. Since sonography is often used as the first imaging method in patients with abdominal complaints, knowledge about postsurgical appearance of the gastrointestinal tract is very important in detecting such pathological conditions.

Afferent Loop Syndrome↗
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

Carotid body tumors: US evaluation.

The ultrasound (US) findings in 20 patients with 23 carotid-body chemodectomas were reviewed. Twenty-two of 23 tumors could be seen at US; the remaining lesion could not be differentiated from surrounding enlarged lymph nodes resulting from thyroid cancer. The lesions were solid, slightly heterogeneous masses that ranged in size from 1.2 to 5.0 cm and were located within the carotid bifurcation. Pulsed Doppler analysis of blood flow within the tumor mass was possible in eight patients with nine chemodectomas, and low-resistance waveforms were obtained from multiple sites within the mass in all cases. The diagnostic possibility of a chemodectoma has to be considered when a solid mass is detected within the carotid bifurcation. On the basis of these findings, as US diagnosis was possible in 18 of 20 patients in the authors' series. Doppler analysis of the mass to evaluate intratumor blood flow is helpful in differentiating chemodectomas from other solid, nonhypervascular masses.

Adult↗
PubMed1992

[Contrast media in echography].

In medical US, the use of specific contrast media to increase the echogenicity of structures and organs changes their absorption of the US beam, and modifies the through-transmission velocity. This can be of great diagnostic value. Contrast media can help depict vessels and cavities, increase the sensitivity of Doppler examination, and make the differentiation of normal and pathologic tissues easier. The products which are currently available do not completely fulfill the needs of clinical researchers. The first papers reporting on some clinical applications of these contrast media in humans are now appearing in literature. Contrast media for diagnostic US can be classified in five groups: 1) free gas bubbles; 2) stabilized gas bubbles; 3) colloidal suspensions; 4) emulsions; 5) aqueous solutions. These agents are quite different, as to both chemical and physical features and distribution within living tissues. Different clinical applications are thus possible for each of them; a unique contrast medium which will meet all the needs of the various clinical situations seems inconceivable at present. Most probably, a variety of products will develop, each with its own application field; in clinical practice, it seems likely that different products will be used, according to the specific clinical needs.

Blood Vessels↗
PubMed1992

[Color-Doppler instruments: their design principles and modes of use].

The use of color-Doppler US equipment allows the clinician to evaluate, at the same time and within the same image, both shape and structure of the examined organs and the flow patterns in the vessels within them. Such information as direction and velocity of blood flow are displayed with a variety of intravascular colors, according to a conventional code. Moreover, this diagnostic method can provide physiological and anatomical pieces of information in the same image and is therefore widely used in medical imaging. However, the images obtained by means of color-Doppler units are not always easy to understand and diagnostic misinterpretations may occur. In this paper we will summarize the physical and technological principles on which such units are based. In the first half of paper, the problems relative to acquisition and construction of the images are presented, together with the different technical approaches used to obtain flow velocity information. Moreover, the relationships between the "black-and-white" and the "color" parts of the images are described. The principles according to which color is assigned to vessels are reported, together with the patterns exhibited by a vessel according to the type of transducer used to examine it. The non-linear correlation between the color scale and flow velocities is also discussed. The second half of the paper deals with technical parameters of color-Doppler scanning, discussing the criteria of choice of transducers, the determination of Doppler angle, the setting of both wall filters and scanning depth. The problem of pulse repetition frequency (PRF) setting is also addressed; this parameter is especially critical in color-Doppler studies. The authors believe that careful setting of all examination parameters and the good knowledge of the physical and technological factors underlying color-Doppler images are the basis for a correct and useful approach to this fascinating technique.

Blood Vessels↗
PubMed1992

[Color-Doppler echography of the testis. Study technique and vascular anatomy].

Color-Doppler sonography has recently made it possible to image scrotal vascularity non-invasively. This study was undertaken to determine the normal color-Doppler appearance and distribution of scrotal vessels and to define the technical principles of the examination. Color-Doppler imaging was effective in detecting both funicolar and testicular vessels. Among these, capsular (25/25), trans-testicular (10/25), centripetal and recurrent (25/25) arteries were easily identified. Waveforms analysis allowed to differentiate veins from arteries within testis and to distinguish (8/10) supratesticular (high impedance pattern with absent diastolic flow) from intratesticular arteries (low impedance pattern with high levels of diastolic flow). The optimal color depiction of scrotal vascularity needed the appropriate selection of several imaging parameters to increase detection of low-velocity, low-volume flows within the small testicular vessels. Such parameters included: PRF (ranging 1500 to 600 Hz), wall filters (ranging 25 to 50 Hz), color gain (maximized for optimal sensitivity while avoiding excessive color noise), color vs. echo priority (ranging 70 to 90%) and color persistence (adjusted to high values). In conclusion, color-Doppler imaging is capable of reliably showing the normal anatomy of testicular vessels. It could make a reliable substitute for scintigraphy and continuous wave Doppler in diagnosing scrotal conditions that alter blood flow.

Adult↗
PubMed1992

[Echography in laryngeal tumors].

During sonographic (US) studies of the neck for the nodal staging of patients with laryngeal neoplasms, the authors observed that, especially in advanced cases, also the primary lesion could be imaged with this method. Therefore, US capabilities were investigated in assessing the local stage of laryngeal neoplasms; the results were compared with clinical and surgical findings. Fifty normal subjects of various ages were previously examined to assess the normal US anatomy of laryngeal structures. The presence of calcifications within the thyroid cartilage is the major obstacle to US imaging of the larynx and is directly related to age; indeed, only 40% of subjects can be examined at the age of 70. Seventeen patients with advanced laryngeal tumors were examined by US. Laryngeal imaging was possible, either in part or completely, in 16 of 17 cases. The results were in agreement with clinical staging in 14 cases; in 2 cases US proved clinical understaging by detecting lesion spread to anterolateral perilaryngeal structures. To conclude, US is not suggested as the method of choice in patients with laryngeal neoplasms. However, in subjects with advanced tumors, also US can image the lesion directly, and even detect tumor spread to surrounding tissues, especially in the anterior and lateral directions. In a few cases, this can contribute to preoperative staging and to select the correct therapeutic approach.

Adolescent↗
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↗
PubMed1991

[Captopril-induced changes in renal flow: evaluation using Doppler echography].

It is well known that angiotensin antagonists cause increase of renal blood flow. We have examined, using duplex Doppler sonography, the changes of renal blood flow velocity induced by oral administration of 50 mg. of Captopril. We examined 19 kidneys in 17 subjects without hypertension. Both peak systolic and diastolic velocities were measured at renal hilum and at arcuate arteries, and the resistive index (RI) was calculated. In conclusion duplex Doppler sonography shows significant increase of blood flow velocities both at the hilum and at the arcuate arteries, without variation of the RI, thus showing that changes affect the whole Doppler wave, both in systole and diastole.

Blood Flow Velocity↗
PubMed1990

[The seriatim echographic assessment of the volume of hepatic metastases].

The quantitative study of neoplastic growth patterns is the ground for a correct clinical approach to patients with malignant tumors, for both prognosis and evaluation of treatment outcome. The growth of 19 hepatic metastases in 13 patients was therefore followed; the lesions diameters were measured by means of US and their volumes were calculated. The results were plotted in semilogarithmic scale and doubling times (DT) were calculated. The DT values observed were ordered according to the origin of the tumors and to their growth rate; our values were in substantial agreement with literature data. Moreover, the differential increase in the metastases diameters along the 3 orthogonal planes was analysed and a significant rate of asymmetrical growth was shown. Changes in the echo structure of the observed metastases were evaluated and the changes in peripheral hypoechoic halo were demonstrated. The authors stress the importance of a correct volumetric study during US follow-up of patients with hepatic metastases.

Adult↗
PubMed1989

Ultrasonic diagnosis of Osgood-Schlatter and Sinding-Larsen-Johansson diseases of the knee.

High resolution ultrasonography of the knee was performed on 82 young patients with clinically suspected Osgood-Schlatter disease and on 30 normal subjects; in 45 pathological cases (55%) comparative X-ray films were taken. The ultrasound pictures were equally or more effective than X-ray images in 45/45 cases; their value was particularly marked for soft tissue study. The typical sonographic changes of the ossification center, of the cartilage, and of the surrounding soft tissues are described and classified, both for Osgood-Schlatter and for Sinding-Larsen-Johansson diseases. These signs are based mainly upon cartilage swelling and edema, fragmentation of the ossification center, thickening of the patellar tendon, and bursitis of the infra-patellar bursa. Ultrasonography is proposed as a simple and reliable method for the diagnosis of knee joint osteochondrosis. The ultrasound picture is also suitable for periodical follow-up the course of the disease.

Adolescent↗
PubMed1989

Sonographic appearances of hemangiomas of skeletal muscle.

The sonographic findings observed in seven patients with muscular hemangiomas were reviewed. An intramuscular mass (size range of 1.5 to 10 cm) was seen in all cases. Five lesions had oval shapes and smooth margins; two had irregular shapes and borders that were not clearly defined. Hyperechoic structure was noted in three lesions; two were hypoechoic; two had heterogeneous echo patterns. Three other muscular hemangiomas (two hyperechoic, one heterogeneous) are reported in the sonographic literature. Therefore, from the literature and from our own observations of hemangiomas, a hyperechogenic mass is the most common sonographic presentation of these tumors. However, there is not a specific sonographic appearance to muscular hemangiomas and other diagnostic tests are needed to establish the diagnosis.

Adolescent↗
PubMed1989

Sonographic appearance of primary retroperitoneal cysts.

The sonographic findings observed in four patients with primary retroperitoneal cysts were reviewed. All lesions presented as fluid-filled masses with anechoic content and regular margins; all increased through transmission. Preoperative location of the cysts within the retroperitoneal space was possible in all cases by either real-time ultrasound (US) analysis of the different relationships of the kidneys and the cysts during respiratory movements or the anterior displacement of surrounding structures. A differential diagnosis among retroperitoneal lesions containing fluid is difficult and cannot be obtained with imaging methods alone. However, preoperative knowledge of both the retroperitoneal location of the disease process and its fluid content may help to narrow the diagnostic possibilities, thus allowing the surgeon to more accurately plan the therapeutic approach to the patient.

Adult↗