[Value of tissue harmonic imaging in biliary lithiasis]. / Apport de l'imagerie harmonique dans la pathologie lithiasique du système biliaire.

AIM OF THE STUDY: To define the role of harmonic imaging in the study of biliary lithiasis. SUBJECTS AND METHODS: We included 50 consecutive patients with suspected biliary lithiasis. Three independent observers compared results of harmonic imaging and conventional ultrasonography. RESULTS: This study showed a better interobserver agreement with harmonic imaging for acoustic shadow (kappa=0.87 vs 0.68) and intra-hepatic biliary stones (kappa=0.79 vs 0.49). More stones and more lithiasic gallbladders were seen with harmonic imaging (27 vs 24) and visualization of gallbladder sludge and the acoustic shadow from stones (P=0.01) was better. Ultrasound examination appears to be easier and faster and the diagnosis is more certain with harmonic imaging than with conventional ultrasonography (P=0.005). CONCLUSION: Harmonic imaging provides more information on biliary lithiasis and a more certain diagnosis.

Use of half-dose gadolinium-enhanced MRI and magnetization transfer saturation in brain tumors.

The aim of this study was to search if half-dose gadolinium (Gd)-enhanced MR imaging with magnetization transfer saturation (MT) can replace standard-dose T1-weighted spin echo (SE) without MT saturation in brain tumors. Thirty patients with a total of 33 brain tumors (14 gliomas, 13 meningiomas, 6 metastases) were prospectively studied using T1-weighted SE half-dose of Gd with MT, and T1-weighted SE standard-dose Gd without MT. The contrast-to-noise ratio (CNR) of the two sequences was calculated and four radiologists reviewed qualitatively the images of the two sequences. There was no significant difference between both techniques for quantitative analysis (Wilcoxon test). However, there was a good agreement between sequences to evidence an intraclass correlation coefficient (r = 0.70) of all lesions. In cases of meningioma, the agreement was better (r = 0.84). The results show a difference in the qualitative data between the two sequences, suggesting the use of the T1-weighted MR images with MT and half-dose of Gd with good results in the whole tested parameters except the lesional edema and the presence of artifacts. Half-dose T1-weighted SE with MT can replace standard-dose T1-weighted SE without MT with no loss of contrast enhancement in investigation of meningiomas and saving 50% of the contrast material.

Error assessment due to coronary stents in flow-encoded phase contrast MR angiography: a phantom study.

Phase contrast magnetic resonance imaging (PC MRI) is a promising method for assessing coronary flow. MR angiography images in the presence of coronary stents display artifacts because of the metal present in the stent. Using a flow phantom, the goal of this in vitro study was to assess quantitatively the effects of flow dephasing caused by magnetic susceptibility in velocity measurements in a region where the artifact is not visualized in a magnitude image. The results showed that for high velocities, significant errors in measurements exist around the stent, outside the susceptibility artifact visible on a magnitude image. J. Magn. Reson. Imaging 1999;10:899-902.

Three-dimensional coronary artery MR imaging using prospective real-time respiratory navigator and linear phase shift processing: comparison with conventional coronary angiography.

Respiratory gating with navigator echo is a recent technique to detect diaphragm position in 3D magnetic resonance (MR) coronary angiography. The purpose of our study was to image proximal coronary arteries and to detect significant stenoses in patients with coronary artery diseases and to compare with contrast enhanced angiography results. Twenty patients with coronary artery diseases who were referred for conventional angiography underwent magnetic resonance angiography (MRA). Three-dimensional gradient echo volumes were acquired using cardiac and respiratory gating and fat suppression. Using reformatted oblique planes and maximum intensity projection technique, visualization coronary segments and detection of significant coronary stenoses were made. Eighty-three coronary segments were analyzed. The sensitivity and specificity were 65% and 93%, respectively. The corresponding positive and negative predictive values were 69% and 91%. This study shows the ability to image correctly coronary arteries and to identify proximal stenoses, but image quality need to be improved for an efficiency detection of coronary artery stenoses in clinical practice.

Subclavian steal syndrome and flow-related aneurysm. Another reason to treat.

A 48-year-old woman presented with a symptomatic right subclavian steal syndrome due to proximal subclavian artery stenosis. Anatomically the innominate artery was absent. Collateral circulation followed the vertebro-vertebral pathway with reversal of blood flow in the ipsilateral vertebral artery. There was also multiple dilated intervertebral collaterals and an associated saccular aneurysm on one of them. Surgical carotid-subclavian transposition permitted relief of clinical symptoms, disappearance of collateral circulation and subtotal regression of the aneurysm. This spontaneous evolution confirmed the role of high-flow in the pathogenesis of some aneurysms and the habitually good prognosis of flow-related aneurysms with correction of the cause. Arteriography still appears essential in diagnosis, pretherapeutic assessment and sometimes post-treatment evaluation in subclavian steal syndrome.

[Value of the angioscan in the etiological diagnosis of cerebromeningeal hemorrhage]. / Intérêt de l'angioscan dans le diagnostic étiologique des hémorragies cérébro-méningées.

Etiologic diagnosis of cerebromeningeal hemorrhage was suspected on CT scan without contrast imaging as a function of distribution of cisternal hyperdensities and/or topography of intracerebral hematomas and/or distribution of parenchymatous hypodensities. It was established in 90% of cases by results of angioscan (type and site of vascular malformation causing the cerebromeningeal hemorrhage are defined with this percent exactitude). Cerebral arteriography provides indispensable precise morphologic data on the vascular malformation: exact site of aneurysm or arteriovenous malformation, orientation of the aneurysm and presence or absence of a collar. It is therefore irreplaceable and will be guided by data from the angio-CT scan.

[Isolated azygos continuation of the inferior vena cava. (Absence of the retrohepatic segment of the inferior vena cava)]. / La prolongation azygos isolée de la veine cave inférieure. (Absence du segment rétrohépatique de la V.C.I.).

The isolated azygos continuation of the inferior vena cave is a very rare variation of this organ. It is accompanied by the absence of the retrohepatic segment of the vena cava with two new observations, the literature is revised and the origin discussed.

[X-ray computed tomographic aspects of gelatinous disease of the peritoneum. Apropos of 5 cases]. / Aspects tomodensitométriques de la maladie gélatineuse du péritoine. A propos de 5 cas.

Gelatinous disease of the peritoneum, designated by Anglo-Saxon authors as peritoneal pseudomyxoma is a rare affection characterized by the presence in the peritoneal cavity of a mucoid substance corresponding to an acid mucopolysaccharide. It develops secondary to an acid mucopolysaccharide. It develops secondary to mucosecreting malignant tumors, particularly of ovarian or appendicular origin, and its capacity to provoke multiple recurrences makes it of fairly poor prognosis. Diagnosis has been improved by the availability of non-aggressive investigations such as ultrasound and particularly computed tomography imaging. Suggestive CT scan signs are hepatic scalloping and a partitioned intraperitoneal effusion. Follow up scans can give data on the course of the disease and detect any complications (renal and digestive lesions, intraperitoneal abscess).

[Value of x-ray computed tomography in the study of the inferior vena cava in urologic practice]. / Apport de la tomodensitométrie dans létude de la veine cave inférieure en pratique urologique.

The CT scan provides a reliable evaluation of the inferior vena cava, especially since the development of second and third generation scanners. It can readily detect congenital malformations and obstructive anomalies complicating renal cancer and it is also able to determine the tumoral or thrombotic nature of the venous obstruction. This excellent definition of the vessel reduces the indications for caval angiography to a few exceptional cases.

[Computed x-ray tomography in the detection of venous extension in renal cancer]. / Apport de la tomodensitométrie dans la recherche de l'extension veineuse des cancers du rein.

With reference to eleven cases of renal cancer with involvement of the inferior vena cava, CT semeiology of this venous complication is detailed. Furthermore, the authors suggest that the images are capable of a pathological interpretation which may indicate whether the obstruction is caused by the tumor or a thrombus. Lastly, the value and limitations of CT scan for detecting caval obstructions associated with renal cancer are analyzed.

[Comparison between the findings of x-ray computed tomography and thoracotomy in the evaluation of locoregional extensions of primary bronchial cancer. Apropos of 45 cases]. / Confrontation entre les données tomodensitométriques et la thoracotomie, dans le bilan d'extension loco-régional du cancer bronchique primitif.

This study concerns 45 patients operated on for a primary bronchial cancer and without local or regional extension on a standard pulmonary radiograph. All subjects had a computed tomographic examination (TDM) on average 28 days before thoracotomy. The comparison was established and the possibility of excising the tumour, joined to an anatomopathological study of the structures removed. The series included only those patients with the following minimal conditions: tumour volume of 4 cms, central tumour, or close to the chest wall. The degree of pleural extension was predicted with a sensibility of 92%, a specificity of 72% (accuracy of 78%). The parietal extension was predicted with a sensibility of 63%, a specificity of 100% (accuracy of 95%). Direct invasion of the mediastinum, present 16 times, was recognized by the scanner in 8 occasions (sensibility 50%) and excluded 23 times out of 25 (specificity 85%). Extension to mediastinal ganglions was detected by the scanner 10 times out of 15; the absence of invasion 27 times out of 30. Thus, if sometimes the TDM examination showed the certainty of local or regional tumour extension, in many cases it did not by itself allow this conclusion. This was true for tumours flush with the pleura or mediastinum because their resolution was insufficient to distinguish neoplastic tissue from normal or inflammatory tissue. The TDM always established a remarkable "map" of the mediastinal glands guiding the biopsy or the thoracotomy in case of enlarged glands. One of the limits includes the possibility of occult extension without glandular hypertrophy.

[Tomodensitometric semiology of Budd-Chiari syndromes]. / Séméiologie tomodensitométrique des syndromes de Budd-Chiari.

Specific computed tomography findings in Budd-Chiari's syndromes are described, based on an analysis of images from five cases. Recognition of these signs assists diagnosis when little evidence of the disease exists or when atypical images are produced. The performance of an angioscan and the study of the changes on repeated imaging provides essential data for liver exploration: on the one hand these emphasize or even unmask the lesions (peripheral multi-lacunar images in the obstructed territory), and on the other hand they assess possible lesions of the inferior vena cava as well as lack of filling of the hepatic veins. Furthermore, they assist avoidance of the trap of pseudo-metastatic images by the particular kinetic of the attenuation of contrasts and the systematization of the lesions. The typical appearance of the liver in Budd-Chiari's syndromes probably results from the conjunction of histopathologic and hemodynamic modifications, notably localized inversions of portal flow and particular by-pass pathways. Computed tomography can be included in exploratory procedures as a non-invasive method capable of confirming the diagnosis of Budd-Chiari's syndrome and of orientating vascular explorations essential for pre-operative evaluation.

[Computed tomography in renal trauma (author's transl)]. / Apport de la tomodensitométrie dans l'étude des traumatismes fermés et récents du rein.

On the basis of a series of 25 cases of closed recent trauma of the kidney examined by scanner, the authors analyzed the information provided by the method and its correspondence with the various lesions encountered. In the course of this study, the scanner appeared to be the method of investigation which, at the present time, offers the best information concerning the severity of parenchymatous damage, as well as the size, nature and course of the perirenal blood or urine collections. Such data being fundamental to therapeutic decisions, the place of the scanner is essential in the evaluation of renal trauma, and, in severe forms, should be performed immediately after the irreplaceable I.V. urography performed as an emergency.

[Contribution of computed tomography to the exploration of aortic aneurysms (author's transl)]. / Apport de la tomodensitométrie à l'exploration des anévrysmes de l'aorte. 50 observations.

A technique for exploring aortic aneurysms is described, and the results analysed in 50 cases (11 thoracic, 32 abdominal, 3 multiple, and 4 with both thoracic and abdominal aneurysms). The diagnostic value of this method appears evident for aneurysms in the thorax, and it can reduce the need for conventional radiological examinations. Results of examination of abdominal aneurysms were compared with those of ultrasonography and angiography. Angiography was more effective for studying collateral lesions, while ultrasonography is still a reliable, non-aggressive, low cost investigational procedure. Computed tomography, however, represents the most polyvalent, non-aggressive technique for evaluating the size of the aneurysm, its thrombotic components, and its extension to neighbouring organs.

[Diagnostic value of the CT scan in suppurative abdominal lesions (author's transl)]. / Apport de la tomodensitométrie dans de diagnostic des suppurations abdominales.

Computed tomography, a relatively non-aggressive method of radiological investigation, can establish diagnosis, and, more particularly, define the site of suppurative lesions in the peritoneal cavity, the retroperitoneal space, and in solid organs (liver, kidneys, spleen). This method was employed to explore the abdomen in 52 patients. Intraperitoneal suppurations were diagnosed in 15 cases after demonstration of a low density mass, which may contain clear pockets of gas or be limited by a higher density wall. In 4 cases, a retroperitoneal lesion was detected (psoas or perinephric abscess). A parenchymatous abscess was present in 6 cases, 4 in the liver, one in the kidneys, and one in the spleen. Using the angioscan technique, after a bolus injection of an iodised contrast medium, improved definition of the limits of the abscess can be obtained. Differential diagnosis of intraperitoneal suppurative lesions in cases of developing haematomas, or in the presence of an intrahepatic abscess, which may be confused with necrotic metastases or post-traumatic ischaemic foci, may be difficult.