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Biomedical subjects

M Bazzocchi

Publications and source records attributed to M Bazzocchi.

At least 37 records · Page 2Linked to original sources
PubMed1998

Contrast media in liver sonography: correlation with enhanced dynamic magnetic resonance imaging.

Both color Doppler sonography and magnetic resonance are imaging techniques which do not use ionizing radiations, but despite this common feature there remain many differences between them. Thus, color Doppler sonography is a cost-effective technique using mechanical waves and providing real-time images while magnetic resonance imaging is much more expensive, uses magnetic fields and radiofrequency energy and provides static images. The former method is very sensitive in detecting focal liver lesions > 1 cm, but its specificity in characterization is not as good, not even with the color Doppler technique. The main differences between color Doppler sonography, with and/or without echocontrast agents, and contrast-enhanced (Gadolinium chelates) dynamic magnetic resonance imaging in focal liver lesions can be summarized as follows: (1) magnetic resonance imaging depicts tumor vascularization only after paramagnetic contrast media injection. Enhanced images completely depend upon the contrast agent and cannot be achieved without it. In contrast, color Doppler signal is not modified by the contrast agent, it just becomes stronger. (2) Contrast-enhanced magnetic resonance signal (as well as contrast-enhanced computed tomography signal) provides more pieces of information than color Doppler signal about the flow characteristics of liver nodules--i.e. it shows not only blood flow (hyper-/hypovascular nodule), but also the interstitial spread of the agent and its wash-out. For example, hepatocellular carcinoma and focal nodular hyperplasia have similar perfusion while agent spread and wash-out decrease very quickly in the former and more slowly in the latter, except for the low decrease of the central scar. (3) Color Doppler technology improvements, higher sensitivity to slow flows and better signal/noise ratio reduce the applications of contrast-enhanced sonography in focal liver lesions because the agents modify only sensitivity and not the imaging in slow flow studies. (4) The higher cost of contrast studies is justified only in selected cases, namely treatment follow-up in the lesions with rich pretreatment vascularization. Finally, the higher cost of contrast magnetic resonance studies is justified to increase sensitivity and especially to allow lesion characterization.

Carcinoma, Hepatocellular↗
PubMed1998

Retroperitoneal nodular fasciitis: magnetic resonance imaging (MRI) and pathological features.

A case of pelvic nodular fasciitis, with particular reference to its peculiar radiological and pathological features is described. Only a few cases of pelvic nodular fasciitis are reported in the English literature and at the best of our knowledge, this is the first case of retroperitoneal origin. This report discusses the role of MRI in the characterization of soft tissue masses. No specific MRI findings of nodular fasciitis were identified and MRI doesn't add any contribution to the differential diagnosis between benign and malignant lesions. As a consequence, the histopathological examination is necessary for a definitive diagnosis.

Journal Article↗
PubMed1996

Primary motor and sensory cortex activation during motor performance and motor imagery: a functional magnetic resonance imaging study.

The intensity and spatial distribution of functional activation in the left precentral and postcentral gyri during actual motor performance (MP) and mental representation [motor imagery (MI)] of self-paced finger-to-thumb opposition movements of the dominant hand were investigated in fourteen right-handed volunteers by functional magnetic resonance imaging (fMRI) techniques. Significant increases in mean normalized fMRI signal intensities over values obtained during the control (visual imagery) tasks were found in a region including the anterior bank and crown of the central sulcus, the presumed site of the primary motor cortex, during both MP (mean percentage increase, 2.1%) and MI (0.8%). In the anterior portion of the precentral gyrus and the postcentral gyrus, mean functional activity levels were also increased during both conditions (MP, 1.7 and 1.2%; MI, 0.6 and 0.4%, respectively). To locate activated foci during MI, MP, or both conditions, the time course of the signal intensities of pixels lying in the precentral or postcentral gyrus was plotted against single-step or double-step waveforms, where the steps of the waveform corresponded to different tasks. Pixels significantly (r > 0.7) activated during both MP and MI were identified in each region in the majority of subjects; percentage increases in signal intensity during MI were on average 30% as great as increases during MP. The pixels activated during both MP and MI appear to represent a large fraction of the whole population activated during MP. These results support the hypothesis that MI and MP involve overlapping neural networks in perirolandic cortical areas.

Adult↗
PubMed1996

[Magnetic resonance with fat-saturation sequences in studying the upper abdomen: the normal semeiological aspects].

The fat-saturation (FAT-SAT) MR technique decreases the signal intensity of fat in tissues, though yielding the T1, T2 and proton-density (PD) information available on spin-echo (SE) sequences. To investigate the potentials of FAT-SAT sequences in MRI of the upper abdomen, the authors carried out a prospective study including 129 subjects, namely 12 normal volunteers and 117 patients with different abdominal conditions. The patients were submitted to T1-weighted SE sequences (TR 500-600 ms, TE 15 ms), T2W SE (TR 1600-1730 ms, TE 80 ms) and PD SE (TR 1600-1730 ms, TE 20 ms). The images obtained with and without fat suppression were compared both qualitatively and quantitatively, with a special emphasis on the normal anatomy of the upper abdomen: we investigated the efficacy of subcutaneous and retroperitoneal fat suppression (116/129 cases, 90%), the reduction in respiratory and chemical shift artifacts (112/129 cases, 87%) and the better visualization of parenchyma (119/129 cases, 93%) and of other abdominal structures. Concerning the quantitative study, we calculated the signal-to-noise ratio (S/N) for liver, spleen, pancreas, adrenal glands, renal cortex and medulla, the improvement of contrast in these organs after retroperitoneal fat suppression (conspicuity) and the increase in contrast between organs (dynamic range). The statistical analysis showed significant differences between the sequences with and those without fat suppression. Correlations were found between observers' and quantitative evaluations, suggesting that the better yield of FAT-SAT sequences is probably due to three factors: 1) retroperitoneal and subcutaneous fat suppression; 2) increase in S/N ratio for pancreas and renal cortex on T1W images; 3) reduction in the dynamic range of signal intensity, which increases contrast between pancreas, adrenal glands and renal cortex relative to adjacent structures, especially on T2W or PD sequences. The results of this study suggest that FAT-SAT sequences are useful because fat suppression increases contrast and improves image quality, reducing respiratory and chemical shift artifacts.

Abdomen↗
PubMed1995

[CT-guided transthoracic needle aspiration of solitary lung lesions. Personal experience in 118 cases].

Fast-scan CT is widely and frequently used to guide fine-needle aspiration biopsy (FNAB) of questionable lung nodules. To investigate technical problems, complications, diagnostic accuracy and indications of this technique, the findings were reviewed relative to 118 patients with negative transbronchial biopsy and sputum cytology who underwent CT-guided FNAB of solitary lung lesions. Over a 25-month period, 73 men and 45 women underwent CT-guided FNAB of lung lesions. The CT unit was a GE 9800; 22-gauge 7/9-cm spinal needles were used in most cases, while 22-G 15-cm Chiba needles were used in 6 cases. In 114 patients one FNAB was performed, 4 patients only requiring the maneuver to be repeated. Regarding the malignant nature of the lesions, there were 70 true positive, 36 true negative, 12 false negative and no false positive cytologic findings; sensitivity was 85.36%, specificity and positive predictive value were 100%, negative predictive value was 75% and diagnostic accuracy 89.83%. Only minor complications occurred: 5 cases of hemophtoe, 7 of peripheral bleeding, 4 of chest pain, 4 vagal reactions and 10 cases of pneumothorax, only one of them requiring drainage. In our experience, only one pass per patient is required and the presence of the cytopathologist is unnecessary, since in most of our cases (114/118) the diagnosis was made at the first FNAB performed by the radiologist. CT allowed the lesions to be approached easily and precisely, which is useful especially in small, peripheral or hilar, nodules missed or poorly defined by radiology. To conclude, CT-guided transthoracic FNAB can be suggested as the method of choice to diagnose lung lesions which are difficult to puncture endoscopically because of size or location, and in suspected metastases. Moreover, FNAB can be used as second-line method in the lesions where endoscopic biopsy cannot be performed or whose findings are negative.

Adenocarcinoma↗
PubMed1993

Ultrasonography and plain film versus intravenous urography in ureteric colic.

Urography (IVU) is considered the best first investigation in patients with suspected ureteric colic, but recently ultrasonography (US), combined with a plain film of the abdomen (KUB), has been suggested as an alternative. We have undertaken a prospective study to see if this approach can be used in an Emergency Department by radiologists with different amounts of ultrasound experience. Some 180 patients with suspected ureteric colic presenting to the Emergency Department over an 8-month period were studied. They had a plain abdominal film (KUB) and US examination of the kidneys, ureters and bladder following hydration. Some 120 patients subsequently underwent IVU at a mean interval of 3.5 days after the ultrasound examination. Of these, 15 patients passed a stone before their IVU. Of the remaining 105 patients, 44 had an IVU positive for stone and 61 had a negative IVU. Fifty of the 60 patients who did not have an IVU had clinical follow-up and 31 had ultrasound. Our findings in this prospective study suggest that in the hydrated patient the combination of KUB plus US is a sensitive but not very specific screening test (sensitivity 95%, specificity 67%). Because of the high negative predictive value of KUB plus US (95%), urography is not likely to be helpful when KUB plus US are negative. Urography is indicated only if KUB plus US findings are equivocal or if intervention is necessary. If we had used KUB plus US alone as the first test in our patients, urography would have been unnecessary in approximately 60%. Twenty per cent of our patients passed a stone in the first 48 h.

Colic↗
PubMed1993

[The use of automatic devices for ultrasonography-guided histologic biopsy of breast lesions].

The authors report their experience with the use of biopsy guns for the histologic sampling of breast lesions. Cytologic sampling by means of FNAB has been preferred so far because it was thought to be simpler, less risky and more reliable. Nevertheless, cytologic sampling exhibits several drawbacks--e.g., the need of repeated punctures to get sufficient cell material, frequent problems in diagnosing benign lesions and the decisive influence of the operator's skills. The use of biopsy guns for histologic sampling solves the above problems, because the value of the sample is not affected by the operator's skills; moreover, fewer punctures are needed and their value does not depend on lesion nature. Our series of cases includes 65 patients who underwent histologic sampling for suspected lesions over 10 months. A hundred and seventy-two samples were collected and 77 lesions were diagnosed, 47 of them malignant and 30 benign (fibroadenomas, fibrocystic changes, epitheliosis). Sensitivity, specificity and diagnostic accuracy of the method were 93.6%, 100% and 96.1%, respectively, with 6.4% false negative due to 3 cases where the lesion was not centred due to misguidance.

Adult↗
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↗
PubMed1991

[The imaging diagnosis of hepatic focal nodular hyperplasia].

Focal nodular hyperplasia (FNH) is a rare benign hepatocellular tumor occurring in noncirrhotic patients, mostly females, 20-50 years of age. It is usually asymptomatic. The authors took the lead from 5 cases of FNH studied over last year to analyze the different patterns exhibited by the condition on the various imaging techniques currently available. At scintigraphy with 99mTc DISIDA or with TcSC, FNH can be hyper, normal, or hypocaptating. On US scans, the lesion is often homogeneous and isoechoic, but it can also be hyper/hypoechoic. With Doppler US, high-flow signals can be observed. On unenhanced CT scans the lesion is solid, well-demarcated, isodense or slightly hyperdense; sometimes it shows a central hypodense area corresponding to fibrovascular scar. On postcontrast scans it appears hyper/isodense. At dynamic CT the lesion density, which is high during the arterial phase, decreases quickly in the parenchymal and the venous phases and reaches equal/inferior values to surrounding liver parenchyma. On liver angio-CT it is sometimes possible to visualize the bile ducts in the central scar. At angiography, FNH is hypervascular and homogeneous. On MR scans, in T1-weighted SE sequences, the condition is isointense or slightly hypointense, whereas on T2-weighted pulse sequences it is slightly hyperintense; the central scar is hypointense on T1, and hyperintense on T2, weighted scans. As we have no pathognomonic patterns but only orientative ones, a reliable differential diagnosis with hepatocellular adenoma (HA) and fibrolamellar hepatocellular carcinoma (FL-HCC) must be based on biopsy or cytology or, even better, histology. The differential diagnosis is nevertheless necessary because, while FNH does not usually require a surgical approach but only a radiological follow-up, both HA (due to possible bleeding and degeneration) and FL-HCC require surgery.

Adult↗
PubMed1991

[Transvaginal echocystourethrography].

The anatomo-physiologic appearances of female urination obtained with a new ultrasonographic technique is illustrated. The technique is performed using an intravisceral linear probe positioned in the vagina and a special chair which allows the urination in physiological position; at the same time the urination is videorecorded. The results, compared with X-Ray cystourethrography, enabled us to show the normal aspects (both dynamic and morphologic) and several pathologic aspects. Basing upon the direction of the urethra, it is possible to establish the change of the position of the floor and the neck bladder, which are often responsible of stress incontinence. The Authors stress the relative simplicity and noninvasiveness of the echographic technique. X-Ray radiation aren't used: this test is particularly advisable to study the urination disease of women in fertile-age.

Adult↗
PubMed1991

[Echography: problems and errors in the diagnosis of renal masses].

US plays an extremely important role in the diagnosis of renal masses. However, a number of diagnostic difficulties still exists in both identification of the mass and definition of its nature. The most frequent causes of diagnostic errors are discussed. Errors may be due to the radiologist, to technical limitations, and to the lesion itself. The radiologist is responsible for inexperience and negligence (incorrect application of the technique, limited clinical information, poor knowledge of US findings). Technical limitations are due to poor spatial and contrast resolution, to extremely fat patients, and to artifacts. As far as lesions are concerned, cystic and solid masses must be distinguished, since the problems are different. As for cystic lesions, problems are relative to their visualization and to the definition of their nature in cases of atypical or complex cysts, due to the complexity of some US findings. The latter involve both cystic wall and content and are related to calcifications, septa, vegetations, blood, purulent debris. In case of solid masses, problems concern the identification of small renal tumors, the differentiation among the various anatomical variants, the differential diagnosis of benign from malignant tumors, and the evaluation of tumor extent. The authors conclude that, whereas operator-dependent errors can be avoided, those inherent to technical parameters and to the lesion itself represent the diagnostic limitation of US.

Diagnostic Errors↗