[Imaging of cystic liver diseases]

The high frequency of benign and asymptomatic liver cysts must not underevaluate the potential diagnostic difficulties of liver cystic diseases. Complicated liver cyst or cystic mass of various origin, such as developmental, neoplastic or inflammatory, are important to be recognized by the radiologist. The diagnostic approach is depending on the number of lesions and their dissemination. The presence of a wall, the internal structure of the lesion, particularly the MR signal and the proximity of the biliary tree are the main diagnostic criteria. Some less frequent but characteristic unusual features need to be memorized.

[Clinical and angiographic parameters affecting the quality of 16 slice spiral CT in the diagnosis of restenosis after stenting the left main coronary artery]

The metallic component of coronary stents makes it difficult to study their lumen by angio scanner. The object of this preliminary study was to appreciate the factors influencing the diagnosis of restenosis after stenting the left main coronary artery by 16-slice spiral angio CT. This Monocentric study included 27 patients who underwent 16-slice spiral angio CT six months after stenting of the left main coronary artery. It was possible to assess the stent lumen in 21 patients (78%) and no cases of > 50% restenosis were observed. In 4 patients, hypodense zones adjacent to the stent links were observed suggesting moderate intimal hyperplasia. The tests for ischaemia were normal in 3 of these patients. Coronary angiography and endocoronary ultrasound excluded significant restenosis in the fourth patient. In univariable analysis, the facors associated with good or excellent angioscanner quality (45% of patients) were Ostial stenosis (p = 0.03), no or minimal calcification on initial coronary angiography (p = 0.0S), stent diameters > 3.5mm (p = 0.03), heart rates < 60/min (p = 0.04), absence of extrasystoles (p = 0.05) during acquisition. In multivariable analysis, the only significant factors were absent or minimal calcification and stent diameters > 3.5mm (p = 0.02). The multidetector scanner seems a very promising method of investigating patients who have undergone stenting of the left main coronary artery but this study shows that certain clinical and angiographic parameters are limiting factors of surveillance with a 16-slice angioscanner.

[Diagnosis of iron overload]

Hepatic iron overload conditions can be classified as genetic, mainly related to HFE haemochromatosis, and secondary, mainly associated with haematological and hepatic disorders and with metabolic syndrome. The strict affirmation of iron excess relies upon liver biopsy, MRI or calculation of the amount of iron removed through phlebotomies. Determination of its cause relies upon the assessment of transferrin saturation which, when increased, suggests the diagnosis of either haemochromatosis--implying HFE testing--or overload secondary to dysmyelopoiesis or to end-stage cirrhosis, and, when normal, suggests the diagnosis of dysmetabolic iron overload syndrome.

Fistule pancréatique post-traumatique : succès du traitement endoscopique par endoprothèse

INTRODUCTION

The risk of complications and the severity of pancreatic trauma depend on the status of the main pancreatic duct. Endoscopic retrograde pancreatography (ERCP) has emerged as the technique of reference for assessing pancreatic ductal anatomy, and it also permits therapeutic intervention by the endoscopic placement of an endoprosthesis.

CASE

We report a pancreatic fistula attributable to posttraumatic rupture of the main duct, undiagnosed before ERCP and successfully treated by endoscopic stent placement.

DISCUSSION

ERCP has emerged as a tool for both diagnosis and treatment. Major traumatic pancreatic duct disruptions can be diagnosed more easily and managed successfully by endoscopic stent placement, thereby avoiding surgical morbidity. ERCP is impractical in emergency settings for many reasons. Magnetic resonance pancreatography may be useful for establishing the type and extent of pancreatic lesions and for selecting patients for endoscopic treatment.

[Spontaneous peri-pancreatic hematoma associated with celiac trunk stenosis: diagnostic difficulties and therapeutic management]

We report a case of spontaneous peri-pancreatic hematoma which was associated with a celiac trunk stenosis. Hematoma was probably due to the rupture of a pancreaticoduodenal artery aneurysm. This diagnosis of pancreatic carcinoma, initially retained, illustrates the difficult diagnostic process. Therapeutic modalities for preventing recurrence are discussed.

Non-invasive assessment of hepatic iron stores by MRI

BACKGROUND

MRI has been proposed for non-invasive detection and quantification of liver iron content, but has not been validated as a reproducible and sensitive method, especially in patients with mild iron overload. We aimed to assess the accuracy of a simple, rapid, and easy to implement MRI procedure to detect and quantify hepatic iron stores.

METHODS

Of 191 patients recruited, 17 were excluded and 174 studied, 139 in a study group and 35 in a validation group. All patients underwent both percutaneous liver biopsy with biochemical assessment of hepatic iron concentration (B-HIC) and MRI of the liver with various gradient-recalled-echo (GRE) sequences obtained with a 1.5 T magnet. Correlation between liver to muscle (L/M) signal intensity ratio and liver iron concentration was calculated. An algorithm to calculate magnetic resonance hepatic iron concentration (MR-HIC) was developed with data from the study group and then applied to the validation group.

FINDINGS

A highly T2-weighted GRE sequence was most sensitive, with 89% sensitivity and 80% specificity in the validation group, with an L/M ratio below 0.88. This threshold allowed us to detect all clinically relevant liver iron overload greater than 60 micromol/g (normal value <36 micromol/g). With other sequences, an L/M ratio less than 1 was highly specific (>87%) for raised hepatic iron concentration. With respect to B-HIC range analysed (3-375 micromol/g), mean difference and 95% CI between B-HIC and MR-HIC were quite similar for study and validation groups (0.8 micromol/g [-6.3 to 7.9] and -2.1 micromol/g [-12.9 to 8.9], respectively).

INTERPRETATION

MRI is a rapid, non-invasive, and cost effective technique that could limit use of liver biopsy to assess liver iron content. Our MR-HIC algorithm is designed to be used on various magnetic resonance machines.

Squamous cell carcinoma arising in a hepatic forgut cyst

We report the second case of squamous cell carcinoma arising in a hepatic foregut cyst (CHFC) in a 40-year-old woman. Microscopically, the lining of the cyst was composed of ciliated columnar epithelium, gastric and squamous epithelium. The squamous epithelium showed areas with dysplastic changes and other areas with carcinomatous transformation. In this congenital lesion, it was not surprising to find squamous and gastric mucosa because oesophagus, stomach, and tracheobronchic tree derive from the embryologic foregut. Squamous carcinoma might develop in a context of inflammation as in biliary cyst. In agreement with the first case described in the literature, this report also suggests that a large-sized symptomatic hepatic cyst should be excised.

Aceruloplasminemia: new clinical, pathophysiological and therapeutic insights

Aceruloplasminemia is an autosomal recessive disease of iron overload associated with mutation(s) in the ceruloplasmin gene. We report here a new case of aceruloplasminemia in a woman who is a compound heterozygote for two new mutations. Besides this novel genotypic profile, this observation provides new insights on: (i) iron metabolism with normal erythroid repartition, in the absence of serum non-transferrin-bound iron and with an increase of 59Fe plasma clearance; (ii) hepatic abnormalities associated with the presence of iron-free foci; (iii) the therapeutic management of the disease, chronic subcutaneous infusion of deferrioxamine being remarkably effective at reducing hepatic iron overload.

Increased body iron stores in elite road cyclists

BACKGROUND

One third of French elite road cyclists were found to have hyperferritinemia on antidoping control tests performed during the Tour de France in 1998.

PURPOSE

This study was undertaken to determine whether hyperferritinemia corresponded to elevated body iron stores or not and, affirmatively, what were its mechanism, its clinical consequences, and its spontaneous course.

METHODS

83 elite road male cyclists presenting with hyperferritinemia, defined as serum ferritin level greater than 300 microg.L-1, were studied with respect to consumption of iron and other drugs, serum iron tests, HFE mutations, and hepatic iron concentration (HIC; N < 35 micromol.g-1 dry weight).

RESULTS

All cyclists were asymptomatic and had normal physical and cardiac examination. Their median (range) serum ferritin, serum iron, and transferrin saturation levels were 504 microg.L-1 (306-1671), 20 micromol.L-1 (8.5-36.3), and 39% (20-76), respectively. HIC was increased in 24/27 up to 187 micromol.g-1. Allelic frequency of the H63D mutation was increased in cyclists when compared to controls (P = 0.04). However, iron tests did not differ according to HFE genotypes. Most cyclists (89%) had been supplemented with iron. The median iron supplementation was 25.5 g (range: 1.4-336) and correlated well (P = 0.002) with serum ferritin. Evolution of serum ferritin levels did not differ whether cyclists had been continuing iron supplementation or not.

CONCLUSION

Hyperferritinemia in elite road cyclists accounted for increased body iron stores caused by and persisting after cessation of excessive iron supplementation. Even when mild, iron excess may expose to long-term complications and should be removed, at least at the time when professional cyclists retire. To prevent iatrogenic iron overload, supplementation with iron must be done according to serum ferritin follow-up and not either blindly or on the basis of serum iron determination only.

[Quantification of iron overload]

Iron overload involves primarily hepatocytes in case of digestive hyperabsorption (hemochromatosis and dyserythropoiesis) and macrophages in case of transfusional excess. Serum iron and transferrin saturation are poorly correlated with the degree of iron overload. Serum ferritin is a better reflect of iron stores but numerous clinical conditions, unrelated to variations of iron load, can increase the serum level. Biochemical determination of liver iron overload is the gold standard of iron quantification and well correlated to the level of iron burden appreciated by the amount of iron removed by venesection, but its determination necessitates a liver biopsy and is dependant of sampling error in case of heterogeneous iron deposits (cirrhosis). The sensitivity of computed tomography is insufficient, beeing unable to detect iron overload below 5 times the normal liver iron load, especially in case of associated steatosis. Magnetic resonance imaging is a valuable tool when using T2 weighted gradient echo sequences on 1.5 Tesla magnet and permits non invasive iron overload quantification.

The RETAIN project: DICOM teleradiology over an ATM-based network. Radiological Examinations Transfer on an ATM Integrated Network

The RETAIN project (Radiological Examinations Transfer on an ATM Integrated Network) has aimed at testing videoconferencing and DICOM image transfers to get advice about difficult radiological cases over an asynchronous transfer mode (ATM)-based network, which affords a more comfortable interface than narrow-band networks and allows exchange of complete image series using the DICOM format of studies. For this purpose, an experimental ATM network was applied between six university hospitals in four different countries. An assessment of the functionalities of the system was performed by means of log-file analysis, video recording of the sessions and forms filled out by the participants at the end of each session. Questionnaires were answered by the users at the end of the project to bring out perspectives of utilisation and added value. We discussed 43 cases during 20 sessions. For technical or organisational problems, only 20 of the 36 planned sessions took place. The throughput over ATM (10.5 Mbit/s, 20 times faster than six ISDN B-channels) was adequate. Despite the experimental configuration of the network, the system was considered as satisfactory by all the physicians. In 72 % of the sessions, the expected result (answer to the question) was gained. By common consent, videoconferencing was unanimously regarded as a prominent tool in improving the interaction quality. Asynchronous transfer mode is an efficient method for fast transferring of radiologic examinations in DICOM format and for discussing them through high-quality videoconferencing.

Magnetic resonance iron-free nodules in genetic hemochromatosis

OBJECTIVE

In hemochromatosis, areas of normal hepatic magnetic resonance (MR) signal intensity indicate the presence of iron-free-nodules, which are strongly suspected of being neoplastic. The goal of the study was to define the prevalence and the nature of these iron-free MR nodules at the time of diagnosis in 116 patients included in a prospective study assessing the accuracy of MR imaging (MRI) in the quantification of liver iron overload.

METHODS

Seventy-nine of the 116 patients had homozygous hemochromatosis on a phenotypic basis. Fifteen-millimeter-thick contiguous slices were performed using T1- and T2-weighted gradient echo sequences with a 0.5 Tesla magnet.

RESULTS

Six of 79 homozygous hemochromatotic patients had one or more MR iron-free nodules. Five of the six patients proved to have malignant tumors. Four of six iron-free nodules were hepatocellular carcinoma (5% in the hemochromatosis group and 17.5% in hemochromatotic patients with severe fibrosis).

CONCLUSIONS

The present data confirm the high prevalence of liver cancer at the time of diagnosis, mainly in cirrhotic patients greater than 45 years of age, and indicate that, when performing MRI for liver iron quantification, a complete hepatic MRI examination is preferable to a simple signal measurement in patients at risk for hepatocellular carcinoma.

Influence of the teleradiology technology (N-ISDN and ATM) on the inter-hospital management of neurosurgical patients

We set out to assess the influence of a teleradiology network on the relations between a general hospital and a 100 km distant university hospital in the context of neurosurgical emergencies, and compared a commercially available technology, N-ISDN (Narrowband Integrated Service/Digital Network), to an emerging technology, ATM (Asynchronous Transfer Mode). The evaluation was conducted using records of advice request calls and patient transfers. Three phases were considered: without teleradiology, with transfer of digitized images over N-ISDN at 64 kbps, and with an experimental ATM network at 10.5 Mbps with DICOM image transfers and videoconferencing. Additionally, staff meetings over ATM videoconferencing were set up. To assess the ATM service, we used log files and questionnaires, 108 advice requests were studied over a 18 month period. The average transmission time for one examination was 38 s with full DICOM image resolution over ATM, versus 150 s with 10:1 JPEG (Joint Photographic Expert Group) compression over N-ISDN. Up to 50% unnecessary patient transfers were avoided. Advice requests increased fourfold, and non-urgent advice requests increased from 0 to 21%. Despite the experimental configuration of the ATM network, the service gave satisfaction to all the physicians. Videoconferencing was unanimously regarded as a prominent tool to improve the quality of interaction. It was particularly useful for non-urgent cases and distant staff meetings. Teleradiology can improve the relations between hospitals through an increase of urgent and non-urgent advice requests. Asynchronous transfer mode is an efficient way for fast transfer of radiological examinations in DICOM format and for discussing them through high-quality videoconferencing.

Analysis of cerebrovascular diseases by a new 3-dimensional computerised X-ray angiography system

We set out to validate the concept of three-dimensional (3D) angiography. We evaluated the sensitivity and the quality of morphological analysis mode possible by an experimental system for imaging cerebrovascular disease versus standard digital subtraction angiography (DSA). The system, the 3D Morphometer, is a computerised X-ray angiography unit capable of acquiring a set of two-dimensional (2D) projections during a rotation and then reconstructing a 3D volume from them. We studied 78 patients with suspected cerebrovascular disease. 3D and 2D images (standard 2D DSA performed during the same procedure), were reviewed blindly to assess detection and display of morphological characteristics of cerebrovascular diseases. We found 53 aneurysms, 22 arteriovenous malformations and two venous angiomas. On 3D angiography we detected two aneurysms we missed on 2D angiography. In 47 aneurysms on which further data were obtained during surgery or embolisation, the 3D angiography allowed more accurate analysis of the neck and surrounding vessels in cases in which the 2D angiographic findings were doubtful. Assessment of arteriovenous malformations was equivalent with both techniques. Under the conditions of our study, the technical constraints being the same for both methods, 3D angiography was superior to 2D angiography. Implementation on C-arm vascular systems is being evaluated.

[Test of a teleradiology network based on ATM (asynchronous transfer mode)]

The retain project (Radiological Examination Transfer on ATM Integrated Network) consisted in teleradiology trials focused on pediatric imaging between two university hospitals. Rennes (France) and Barcelona (Spain) using an integrated broadband communication network based on ATM (asynchronous transfer mode), as part of a European research program. The network used was a full 10 Mbits/s ATM network directly connected to local PACSs (medical imaging hospital networks). One important reason to explicitly consider ATM for medical imaging is that multimedia applications on such networks allow integration of digital data and person-to-person communication. The utility of broadband communication for teleradiology has been confirmed. High quality video and sound are important for both human communication and medical video transfer. The project led to guidelines regarding technical options still open to improvement.

Hemochromatosis: diagnosis and quantification of liver iron with gradient-echo MR imaging

PURPOSE

To assess the role of magnetic resonance (MR) imaging in detection and quantification of liver iron overload.

MATERIALS AND METHODS

MR imaging at 0.5 T was prospectively performed on 77 patients (67 with liver iron overload and 10 without) who underwent a liver biopsy with biochemical determination of the liver iron concentration (LIC) (normal, < 36 mumol per gram of liver tissue [dry weight]). Ratios of signal intensities and liver T2 relaxation time were calculated from images obtained with spin-echo and breath-hold gradient-echo (GRE) sequences.

RESULTS

Liver-to-tissue signal intensity ratios were better correlated with LIC than T2 relaxation time. Long-echo-time GRE sequences were the most sensitive for detection of slight overload. Thus, high sensitivity (94%) and specificity (90%) were obtained with a liver-to-fat ratio threshold of 1. The quantification of iron with MR imaging was accurate when the LIC was 80-300 mumol/g. For heavy overload, above 300 mumol/g, quantification was impossible owing to complete signal loss. Pancreatic and splenic signal intensity were unchanged in most cases.

CONCLUSION

This method, which can be improved by using more sensitive sequences with a high-field-strength system, should be competitive with biopsy for the diagnosis of substantial liver iron overload.

Magnetic resonance imaging and assessment of liver iron content in genetic hemochromatosis

Computed tomography (CT) scanning is not highly sensitive in the assessment of liver iron content and magnetic resonance imaging (MRI) appears to be more efficient. The aim of this study was to determine the effectiveness of MRI in the evaluation of liver iron content using a standard spin-echo technique. The study included 23 patients with genetic hemochromatosis and 24 non-iron-overloaded patients as controls. A comparison was made of: (a) MRI signal intensity of liver, spleen, paravertebral muscles and subcutaneous adipose tissue using two different spin-echo sequences (SE 500/28; SE 2000/28,56); (b) liver attenuation determined by a single energy CT scan; and (c) a biochemical determination of hepatic iron. There was a significant decrease in liver signal intensity in the genetic hemochromatosis group (256 +/- 201, mean +/- S.D.) compared with the control group (801 +/- 413, p less than 0.001), but there was no correlation with liver iron concentration. However, such a correlation was found and was even more highly significant than in CT when the ratio between the liver and another organ was taken into account. For a lower limit of liver/spleen ratio calculated at 0.46 (mean 2 S.D. in the control group), the specificity (0.96) of MRI was satisfactory, but the sensitivity (0.78) remained insufficient (MRI being unable to detect an iron overload of up to 125 mumol/g). Hopefully, these results might be improved in the near future by using more sensitive sequences such as gradient echo sequences.

Superparamagnetic iron oxide: clinical time-response study

Superparamagnetic iron oxide (AMI 25) is a promising new contrast agent for imaging the reticuloendothelial-system. Iron oxide crystals possess a large magnetic susceptibility and enhance proton relaxation rates, especially transverse relaxation (T2). In order to guide the clinical utilization of this contrast media we analyzed 4 patients with malignant lesions of the liver before and after slow intravenous administration (20 mumol Fe/kg) of AMI 25. We performed two magnetic resonance (MR) sequences at different times using a 0.35 T magnet. MR signal-to-noise ratio (SNR) of the reticuloendothelial system (particularly the liver SNR) decrease promptly. The maximum decrease in SNR (67-72% for the liver, 46-65% for the spleen, 23-41% for the bone marrow) is observed 3 h after injection (P less than 0.01). However, except the peak of contrast enhancement in T1-weighted sequences of splenic tissue, the curve describes a plateau within 30 min and 6 h, allowing a delay between injection and imaging. T2-weighted sequences give a greater contrast-to-noise ratio (CNR) by adding the spontaneous tumor contrast to the effect yielded by AMI 25. These results suggest that images must be acquired between 1 and 6 h after intravenous administration of superparamagnetic iron oxide.

[Radiologic aspects of a case of Waldmann's disease]

The Waldmann's disease or intestinal lymphangiectasia is a rare disease. We observed a case which occurred in a 14 years old boy. The disease was discovered in the screening of an intermittent diarrhea. The diagnosis was suspected on biological signs of protein-losing enteropathy and the presence of lymphangiectasias seen during endoscopy. The lymphography was conclusive showing the abnormal opacification of the mesenteric region. The other examinations were also important to assert the idiopathic origin of the disease.

[Anterior rectal duplication. Value of ultrasonic diagnosis]

A case of neonatal anterior rectal duplication is reported. Abdominal ultrasonography revealed a prerectal cystic mass. The different types of rectal duplications and the main differential diagnosis are described. Mechanical obstruction and neoplastic risk make early surgery necessary.

[The value of computerized tomography in the assessment of hepatic iron overload in genetic hemochromatosis]

The aim of the present study was to evaluate the effectiveness of single-energy computed tomography in determining iron overload in idiopathic hemochromatosis, with special reference to slightly overloaded cases. Liver attenuation was determined in 100 patients (46 cases of idiopathic hemochromatosis, 32 cases of chronic liver disease, and 22 normal controls). The iron load was determined for the first two groups by biochemical determination of liver iron concentration (performed in all but 12 subjects in the chronic liver disease group) and hepatic histologic grading. The main results for liver attenuation (upper normal limit, 72 Hounsfield units) showed that despite a high specificity (0.96), this parameter was of low sensitivity (0.63). Although mean liver attenuation in idiopathic hemochromatosis (77 +/- 14) was significantly higher than in chronic liver diseases (53 +/- 17; p less than 10(-4], and normal controls (66 +/- 3; p less than 10(-3], and despite an overall good correlation between liver attenuation and liver iron concentration (r = 0.72; p less than 10(-3], liver attenuation was unable to detect moderate iron overload. Fourteen of 18 patients with a liver iron concentration of less than 150 mumol/g dry liver wt had liver attenuation values of less than 72. Moreover, 3 of 18 subjects with a liver iron concentration of greater than 150 had a liver attenuation of less than 72. Of these 17 false-negatives, only 7 could be attributed to associated steatosis. On the whole, single-energy computed tomography, when used on a routine basis for diagnosing iron overload, is of limited clinical value in idiopathic hemochromatosis due to its poor sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)