Ultrafast MR imaging of the foetus: a study of 25 non-central nervous system anomalies.

PURPOSE: The aim of this paper is to suggest Magnetic Resonance (MR) Imaging as a useful tool in prenatal diagnosis. Although ultrasonography (US) is the imaging technique of choice for prenatal screening, in cases of complex malformations US findings may be sub-optimal and give rise to diagnostic difficulties requiring further investigation. Our study is focused on non-central nervous system (CNS) abnormalities of the foetus imaged using the ultrafast sequence EXPRESS. MATERIALS AND METHODS: 38 women whose foetuses were between 21-34 gestational age were studied. Indications for the examinations included the evaluation of non-CNS abnormalities in 25 cases. Foetal MR imaging was performed on a 1.5 T system (Edge, Marconi Medical System Italia SpA, Vimercate, MI) with the half-Fourier, single-shot, fast spin-echo EXPRESS sequence. Mild maternal and foetal sedation was obtained by oral administration of benzodiazepine (1 mg). RESULTS: In the 25 foetuses investigated for non-CNS pathologies the abnormalities were localised in the chest (9), abdomen (15) and extremities (1). The MR imaging diagnoses were: in the chest - congenital diaphragmatic hernia (CDH) (5), congenital cystic adenomatoid malformation (CCAM) (1), hydrothorax (1), cystic lymphangioma (1), Jeune syndrome (1); in the abdomen - 10 cases of urinary tract diseases - polycystic kidney (4), crossed renal ectopia (2), unilateral renal agenesis (1), solitary pelvic kidney (1), bilateral stenosis of ureteropelvic junction (1), duplex collecting system in association with controlateral hydroureteronephrosis (1)#151;5 cases of non-urinary tract pathologies#151;cystic lymphangioma of the liver (1), abdominal cystic lymphangioma (1), gastroschisis (1), gastric duplication (1), cavernous haemangioma of the liver (1); in the extremities - longitudinal hemimelia (1). CONCLUSIONS: In our experience MR is to be considered a useful though adjunct study to prenatal US particularly in the evaluation of lung parenchyma, congenital diaphragmatic viscera herniation, thoracic masses, pleural effusion, abdominal cystic masses, and urinary tract malformations. The ultrafast EXPRESS sequence enables a complete study to be performed in a very short time; as a consequence the examination is well tolerated by the patient. Currently there is no legislation which regulates the use of magnetic fields in MR, only a series of recommendations based on studies on animal embryos and foetuses, on pregnant women exposed to magnetic fields and follow-up studies of children exposed to MR during gestation. Therefore the decision to proceed with foetal MR should be made on a case-by-case basis in close consultation with the referring obstetrician. Considering the results, in our opinion the potential of MR in the evaluation of a wide variety of non-CNS foetal diseases will increase in the near future.

Mycotic aneurysm of the thoracic aorta presenting as pneumonia.

Mycotic aneurysms of the thoracic aorta rarely occur in children. We report an unusual case of a mycotic aneurysm of the descending aorta in a 4-year-old boy presenting with respiratory tract infection, which was rapidly complicated by atelectasis of the left lung. The patient's mycotic aortic aneurysm was diagnosed by contrast-enhanced spiral CT, whereas conventional chest radiographs did not detect its presence. An unsuspected mild aortic coarctation was also diagnosed at the time of admission. This case demonstrates that an aortic aneurysm may clinically and radiologically manifest itself with respiratory tract infection and atelectasis and that contrast-enhanced spiral CT is a fast and powerful tool for establishing the diagnosis.

[Application of spiral computerized tomography in the study of traumatic lesions of the thoracic aorta]. / Applicazioni della Tomografia Computerizzata spirale nello studio delle lesioni traumatiche dell'aorta toracica.

PURPOSE: Acute thoracic aortic injuries account for up to 10-20% of fatalities in high-speed deceleration road accidents and have an estimated immediate fatality rate of 80-90%. Untreated survivors to acute trauma (10-20%) have a dismal prognosis: 30% of them die within 6 hours, 40-50% die within 24 hours, and 90% within 4 months. We investigated the diagnostic accuracy of Helical Computed Tomography (Helical CT) in acute traumatic injuries of the thoracic aorta, and the role of this technique in the diagnostic management of trauma patients with a strong suspicion of aortic rupture. MATERIAL AND METHODS: We compared retrospectively the chest Helical CT findings of 256 trauma patients examined June 1995 through August 1999. All patients underwent a plain chest radiograph in supine recumbency when admitted to the Emergency Room. Chest Helical CT examinations were performed according to trauma score, to associated traumatic lesions and to plain chest radiographic findings. All the examinations were performed with no intravenous contrast agent administration and the pitch 2 technique. After a previous baseline study, contrast-enhanced scans were acquired with pitch 1 in 87 patients. All examinations were assessed for the presence of mediastinal hematoma, periaortic hematoma, traumatic pseudodiverticulum, irregular aortic wall or contour and intimal flap as signs of aortic rupture. RESULTS: Helical CT showed thoracic aortic lesions in 9 of 256 patients examined. In all the 9 cases we found a mediastinal hematoma and all of them had positive plain chest radiographic findings of mediastinal enlargement. Moreover, in 6 cases aortic knob blurring was also evident on plain chest film and in 5 cases depressed left mainstem bronchus and trachea deviation rightwards were observed. All aortic lesions were identified on axial scans and located at the isthmus of level. Aortic rupture was always depicted as pseudodiverticulum of the proximal descending tract and intimal flap. We also found periaortic hematoma in 6 cases and intramural hematoma in 1 case. There were no false positive results in our series: 7 patients with Helical CT diagnosis of aortic rupture were submitted to conventional aortography that confirmed both type and extension of the lesions as detected by Helical CT, and all findings were confirmed by gross inspection at surgery. No false negative results have been recorded so far: untreated aortic ruptures are fatal within 4 months in 90% of patients, or they may evolve into chronic pseudoaneurysm in about 5% of survivors. CONCLUSIONS: In our experience Helical CT had much higher diagnostic sensitivity and specificity than plain chest radiography. In agreement with larger published series, in our small one the diagnostic accuracy of Helical CT was 100% in the evaluation of traumatic aortic ruptures. Moreover, Helical CT is faster and less invasive than conventional aortography, which makes this diagnostic modality increasingly used and markedly improves the management of the serious trauma patient. The more widespread use of this diagnostic tool has permitted to standardize the technique and now Helical CT can be used not only as a screening modality for patients that undergo digital aortography, but also as a reliable diagnostic method for surgical planning.

[Short TR--short TE and UTSS sequences compared in a NMR study of focal neoplastic pathology in the liver]. / Sequenze "short TR--short TE" e "UTSS" a confronto nello studio NMR della patologia neoplastica focale del fegato.

From December 1987 to January 1989, 66 patients were studied by liver MR imaging: 38 of them were found to have liver tumors, and 28 were studied as a control group. The authors' purpose was to compare the diagnostic accuracy of 0.5 T MR imaging to that of other techniques (CT and US), using mixed Spin-Echo and Inversion Recovery sequences (UTSS). Spin-Echo sequences were used first, with very short repetition times (TR 260, TE 20). Mixed sequences (UTSS) followed, both T1-weighted, lasting 12' and 13' respectively, and then T2-weighted Multiecho sequences lasting 9'. T1-weighted Inversion Recovery sequences provided with good contrast between normal and neoplastic parenchyma, and demonstrated all the lesions shown by other techniques. UTSS proved to be the most sensitive sequence in exactly defining the lesion and its relationship to hepatic vessels. Signal characteristics of T2-weighted Multiecho sequences allowed some neoplastic types to be distinguished that were found to have a particular behavior, especially hemangiomas. T1 and T2 maps were used to characterize the different lesions.