Impact of iterative reconstructions on image quality and detectability of focal liver lesions in low-energy monochromatic images.

PURPOSE: To assess the impact of iterative reconstructions on image quality and detectability of focal liver lesions in low-energy monochromatic images from a Fast kV-Switching Dual Energy CT (KVSCT) platform. METHODS: Acquisitions on an image-quality phantom were performed using a KVSCT for three dose levels (CTDIvol:12.72/10.76/8.79 mGy). Raw data were reconstructed for five energy levels (40/50/60/70/80 keV) using Filtered Back Projection (FBP) and four levels of ASIR (ASIR30/ASIR50/ASIR70/ASIR100). Noise power spectrum (NPS) and task-based transfer function (TTF) were measured before computing a Detectability index (d') to model the detection task of liver metastasis (LM) and hepatocellular carcinoma (HCC) as function of keV. RESULTS: From 40 to 70 keV, noise-magnitude was reduced on average by -68% ± 1% with FBP; -61% ± 3% with ASIR50 and -52% ± 6% with ASIR100. The mean spatial frequency of the NPS decreased when the energy level decreased and the iterative level increased. TTF values at 50% decreased as the energy level increased and as the percentage of ASIR increased. The detectability of both lesions increased with increasing dose level and percentage of ASIR. For the LM, d' peaked at 70 keV for all reconstruction types, except for ASIR70 at 12.72 mGy and ASIR100, where d' peaked at 50 keV. For HCC, d' peaked at 60 keV for FBP and ASIR30 but peaked at 50 keV for ASIR50, ASIR70 and ASIR100. CONCLUSIONS: Using percentage of ASIR above 50% at low-energy monochromatic images could limit the increase of noise-magnitude, benefit from spatial resolution improvement and hence enhance detectability of subtle low contrast focal liver lesions such as HCC.

[Paraspinal arteriovenous malformations with perimedullary venous drainage]. / Malformations artérioveineuses paraspinales à drainage veineux épidural.

Symptoms of chronic myelopathy in cases of paraspinal arteriovenous malformations are most often related to perimedullary venous drainage. Here, we report on three cases of such malformations that have unique epidural venous drainage. These thoracolumbar lesions manifested as isolated back pain (in two cases) and S1 lumboradicular pain (in one case). MRI presented evidence to suggest a diagnosis of these rare conditions, based on signs of vertebral erosion, signal loss (flow void) on T1- and T2-weighted imaging, and partial enhancement after gadolinium injection, with no signs of congestive myelopathy. Spinal angiography confirmed the presence of a paraspinal fistula and, at the same time, allowed treatment by intra-arterial onyx injection.

[Imaging of the cervix and the vagina]. / Imagerie du col et du vagin.

US and MRI currently are the best imaging modalities to evaluate pathology of the uterine cervix and vagina. Carcinoma of the cervix is the most frequent indication for imaging. MRI allows preoperative staging of cervical carcinoma based on FIGO classification, and post treatment follow-up. Other uterine cervix diseases are less frequently imaged and include a wide range of entities that most frequently cause increased T2W signal at MR imaging. Pathology of the pelvic floor, vagina, vulva, and perineum also includes a wide range of entities that have seldom been described in the imaging literature.

[Cerebral thrombophlebitis disclosing Behçet disease. Value of high resolution MRI]. / Thrombophlébite cérébrale révélatrice d'une maladie de Behçet. Apport de l'IRM de flux.

A 21-year-old male of Moroccan descent was admitted for inflammatory polyarthralgia and monoarthritis of the left knee. The patient reported a history of recurrent isolated aphthous ulcerations of the oral cavity. He was found to be positive for the HLA B5 antigen. The other investigations for Behçet's disease were negative. During hospitalization, headache responsible for insomnia developed. Neurologic evaluation was normal, as well as funduscopy and spinal tap findings. CT scan images were suggestive of cerebral thrombophlebitis. Magnetic resonance imaging (MRI) disclosed an old thrombosis of the right transverse sinus. Time-of-flight MRI (MRI with sequences adapted to the study of vessels) evidenced recent thrombophlebitis of the left transverse sinus. Cerebral angiography fully confirmed MRI findings. Treatment with a corticosteroid and an anticoagulant was successful. Final diagnosis was Behçet's disease. Subsequently, the patient developed additional features of the disease, including hypersensitivity to pinprick, retinal vasculitis, and erythema nodosum. This case is interesting for two reasons: cerebral thrombophlebitis in Behçet's disease can manifest as localized headache. It occurs in 6 to 13% of patients. Early diagnosis and treatment are essential; MRI features of cerebral thrombophlebitis were confirmed by the cerebral angiogram. MRI established that the thrombophlebitis was of recent onset. MRI may be appropriate as the initial investigation in patients with suspected cerebral thrombophlebitis.

Gynecologic interventional radiology.

Interventional radiology now finds a wide range of applications in the gynecologic area. They can be divided in general procedures applied to gynecology and procedures specific to gynecology.

[Thrombosis of the aorta in newborn infants]. / Thrombose de l'aorte du nouveau-né.

The authors report a case of a neonate presenting with thrombosis of the abdominal aorta following catheterisation of the umbilical artery. The diagnosis was established by ultrasonography in a context of isolated anuria. Immediate disobstruction by Fogarty's method results in cure.

[Study of the annual mortality statistics in a general surgical ward with digestive and vascular orientation at a general hospital center]. / Etude d'une statistique annuelle de mortalité dans un service de chirurgie générale à orientation digestive et vasculaire de centre hospitalier général.

Quality of care has been evaluated in this study by the criterion of mortality in a Digestive and Vascular Surgery unit. The analysis over a one-year period concerned 34 dead patients among 1298 entered and 1,108 operated patients who underwent 1,248 operations. The causes of death have been studied in the 3 groups: non operated (5 patients), digestive (20 patients), vascular (9 patients), with distinction of emergency surgery. Therapeutic habits have been systematically reexamined and considered either adapted or to be modified. Punctual conclusions of such a study are interesting for the medico-surgical team but also for the nursing team. Transparency of mortality for a whole team is a factor of progress by the periodical reappraisal of the therapeutic habits based upon accurate data, and by the better collaboration in the team.

[Congenital diverticulum of the lower choledochus. Apropos of a case with intraduodenal development]. / Diverticule congénital du bas-cholédoque. A propos d'un cas à développement intra-duodénal.

The onset of subicterus in a patient revealed the presence of a congenital diverticulum of lower common bile duct of intraduodenal development. A part from the rarity of this lesion this case is of interest due to the complete range of ultrasound, endoscopic and CT scan imaging performed, the association of a common mesentery and the surgical technique employed. The latter comprised exeresis by transduodenal approach and a side-to-side choledocho-duodenal anastomosis through the intermediary of the diverticular sleeve. The nosology and differential diagnosis of diverticulum of lower common bile duct are discussed and data from a literature review used to describe diagnostic, etiopathogenic and histopathologic aspects as well as complications and treatment of this type of congenital dilatation of lower biliary tract.

[Injury of the common femoral vein with considerable loss of substance. Repair using an internal jugular autologous vein graft]. / Plaie de la veine fémorale commune avec perte de substance importante. Réparation par greffon veineux autogène jugulaire interne.

A recent wound of femoral vein with pronounced loss of substance was repaired using an autogenous internal jugular vein graft. The value of the use of this type of graft in wounds of large venous trunks with marked loss of substance in a potentially contaminated milieu is emphasized.