Benign focal liver lesions: spectrum of findings on SonoVue-enhanced pulse-inversion ultrasonography.

The prevalence of benign focal liver lesions (BFLL) is high both in the general population and in patients with known malignancies. The gray-scale ultrasound (US) technique is usually the first-line imaging modality used in the radiological workup of such lesions, but unfortunately it lacks specificity. Furthermore, Doppler examination may often be unsatisfactory owing to motion artefacts, or when small or deeply located lesions are evaluated. Recently, microbubble-based contrast agents used in combination with gray-scale US techniques, which are very sensitive to nonlinear behavior of microbubbles, have led to a better depiction of both microvasculature and macrovasculature of focal hepati…

Heterogeneous delayed enhancement of hepatic parenchyma after intravenous infusion of sonographic contrast agent: a new hypothesis

Purpose. The aim of this paper was to report a heterogeneous latephase hepatic enhancement pattern observed after administration of a sonographic contrast agent and to present an aetiological hypothesis for the phenomenon. Materials and methods. A total of 1,729 (1,012 women and 717 men; age range 28–82; mean age 51) patients underwent contrastenhanced sonography of the liver. The examination was performed with a low mechanical index (MI <0.09) after injection of sulphur-hexafluoride-filled microbubbles, using different fonographic equipment and different contrast-specific algorithms. Results. Heterogeneous delayed liver enhancement was observed in six patients in the late phase (180 s), wi…

Gd-DTPA in blood-ocular barrier damage: a new diagnostic tool for future application in MRI?

The blood-brain barrier is not the only neuroepithelial blood filter in the body: the eye too is supported by a highly specialised microvascular filter, the so-called blood-ocular barrier (BOB). The BOB is actually divided into a blood-aqueous (BAB) and a blood-retinal (BRB) barrier, filtering the aqueous fluid and biological supplies, respectively, to the retina. The authors’ purpose was to study the possibility of imaging BAB or BRB damage by contrast-enhanced MRI: they examined 21 patients with a 0.5 T system and surface coil. Despite the normal findings in the damaged eyes immediately after a Gd-DTPA bolus, delayed contrast-enhanced MRI was able to show focal or diffuse barrier damage.

Qualitative and quantitative evaluation of solitary thyroid nodules with contrast-enhanced ultrasound: initial results

To assess the feasibility of contrast-enhanced ultrasound (CEUS) of the thyroid gland and to evaluate the potential of this method for characterising solitary thyroid nodules.18 patients affected by solitary thyroid nodules (size range: 0.6 to 3.6 cm; mean: 1.8 cm) confirmed by surgery (nine papillary carcinomas, four follicular carcinomas, three hyperplasias, one follicular adenoma and one Plummer’s adenoma) underwent pulse inversion US at low M.I. (0.06 to 0.08) after i.v. injection of a 2.4-mL bolus of SonoVue. Baseline echogenicity and the dynamic enhancement pattern of each nodule, in comparison with adjacent thyroid parenchyma, were assessed. Signal intensity values on grey-scale imag…

Static magnetic fields generated by a 0.5T MRI unit affects in vitro expression of activation markers and interleukin release in human peripheral blood mononuclear cells (PBMC)

To investigate the effects of the static magnetic field (SMF) generated by a 0.5 T superconducting MRI unit on in vitro activation marker expression and interleukin release in human peripheral blood mononuclear cell (PBMC) samples from healthy volunteers.PBMC samples were split into two groups: exposed and sham-exposed under isothermal conditions. PBMC were exposed for 2 h at 24 degrees C to the SMF of a 0.5 T superconducting MRI unit. Immediately after exposure, both samples were cultured for 24 h at 37 degrees C with or without mitogenic stimulation by phytohaemagglutinin (PHA). PBMC were examined for expression of CD25, CD69 and CD71 by immunofluorescence analysis and supernatants were a…

THE INSTITUTION OF A “SUPERIOR SCHOOL FOR HUMAN AND SOCIAL MEDICINE”

Reversible effect of MR and ELF magnetic fields (0.5 T and 0.5 mT) on human lymphocyte activation patterns.

Purpose: The aim of this study was to investigate the effects of magnetic fields (MF) of different intensity generated by a magnetic resonance (MR) unit (0.5 Tesla) and a double cylindrical coil (0.5 mTesla) on human CD4+ T cell lines. Materials and methods: CD4+ T cells were exposed for two hours under isothermal conditions (37 ± 0.5°C) to the above mentioned MF; a control group was provided for each exposed sample. After exposure, the samples were analysed in the laboratory for the following endpoints: Release of cytokines, expression of surface markers, cell proliferation and levels of cytosolic free-calcium. Results: Exposure to MF for 2 h and subsequent in vitro stimulation in the pres…

MRI of inner ear fluids using modified GRASS sequences: a useful tool in the assessment of the normal and pathological labyrinth

MRI is acquiring a progressively more important role in the investigation of petrous bone disease. Nevertheless, despite the extensive use of MRI in the detection of inflammatory or neoplastic involvement of the seventh and eighth cranial nerves, conventional spinecho images cannot be considered the modality of choice in inner ear imaging “Steady-state sequences” are known to be motion sensitive. By setting a very short repetition time, a large flip angle and a long echo time, one can obtain a sequence sufficiently sensitive to the slow movement of endo- and perilymph. We report our experience in MRI of normal and pathological inner ear with modified GRASS sequences.

Characterization of benign hepatic tumors arising in fatty liver with SonoVue and pulse inversion US.

Background: We describe the spectrum of contrast-enhancement patterns of benign hepatic tumors arising in fatty liver on contrast-enhanced ultrasound (US). Methods: Sixteen patients (12 women and four men) with 27 benign hepatic tumors (17 hemangiomas, eight focal nodular hyperplasias, and two hepatocellular adenomas) arising in fatty liver underwent baseline and pulse inversion US after administration of SonoVue. Two experienced radiologists evaluated baseline echogenicity and dynamic enhancement pattern of each lesion in comparison with adjacent liver parenchyma. Results: After administration of SonoVue, in the arterial phase 13 of 17 hemangiomas showed peripheral globular enhancement and…

Ultrastructural biologic effects of sonography with pulse inversion and microbubble contrast in rabbit liver

Purpose This prospective study was conducted to evaluate the biologic effects of microbubble destruction with pulse-inversion harmonic imaging on rabbit liver parenchyma. Methods The livers of 6 albino rabbits were examined sonographically by a single investigator. Three rabbits underwent contrast-enhanced sonography, with scanning starting 5 seconds after injection by using pulse-inversion harmonic imaging with a mechanical index of 1.2. Four time-triggered images were recorded at a rate of 1 frame every 2 seconds. For comparison, 3 control rabbits had pulse-inversion harmonic imaging with a mechanical index of 1.2 only, without contrast medium. Immediately after sonography, the animals we…

PANCREATIC CARCINOMA VERSUS CHRONIC FOCAL PANCREATITIS: CONTRAST-ENHANCED POWER DOPPLER ULTRASONOGRAPHY FINDINGS

Background: We assessed the potential usefulness of contrast-enhanced power Doppler ultrasonography (US) for differentiating pancreatic carcinoma from chronic focal pancreatitis. Methods: Twenty-six consecutive patients with ductal carcinoma (n=16) and chronic focal pancreatitis (n=10) underwent power Doppler US examinations before and after intravenous injection of an air-based contrast agent (Levovist, Schering, Berlin, Germany). Final diagnosis was obtained by surgery in all patients. The following parameters before and after intravenous administration of contrast agent were evaluated for each lesion: number, morphology and course of the vessels within the lesion and time to maximum dete…

Su di un caso di Schwannoma primitivo intraorbitario

Gli Schwannomi costituiscono il 6,8% dei tumori intracranici ed originano solitamente dai nervi sensitivi, con particolare predilezione per il V e VIII nervo cranico. Uno schwannoma a partenza da un nervo oculomotore costituisce invece una evenienza piuttosto rara, e solo 17 casi di s. del III n.c. sono stati documentati in letteratura. Sono da considerare ancora più rari gli schwannomi ad esclusiva localizzazione intraorbitaria (1–5, 7% dei tumori orbitari). Solitamente tipico dell'uomo adulto, con l'eccezione dei soggetti affetti da Neurofibromatosi di tipo 2, lo schwannoma orbitario esordisce solitamente come un processo espansivo a lento accrescimento, determinante diplopia, esoftalmo …

Biologic effects of ultrasound on liver cells of rat embryos.

Experiments on the biologic effects of ultrasound (US) were carried out on rat embryos exposed for 120 s to a US beam showing features similar to those already employed for diagnostic purposes. Electron microscopic investigation of the liver parenchyma of rat embryos confirmed results obtained from adult guinea pigs with the same duration of exposure, i.e. diffuse vacuolization of cytoplasma and varying degrees of mitochondrial damage.

Color Doppler ultrasonography in pediatric intussusception.

CDU was used in 11 children with intussusception. Demonstration of vascular images within the "pseudokidney" mass was possible in none of 11 cases. Of them, eight could be treated by hydrostatic reduction. In the remaining case, marked edema of the bowel wall did not allow reduction, and surgery had to be performed: no necrosis was observed in the surgical specimen. Both patients in whom CDU failed to demonstrate vascular signals had necrosis at surgery, and bowel resection was performed. Because of the limited number of patients examined at this time, no firm conclusions can be drawn from our experience. However, CDU seems a promising technique in detecting vascular changes occurring in in…

Orbital varices: a tricky diagnosis in MRI

Orbital varix (OV) is a rare condition causing intermittent positional exophthalmos. Because of low venous pressure, OVs tend to collapse, being frequently undetectable in routine CT or MRI examinations. We describe one case of giant intraorbital varix studied with CT and MRI techniques.

MRI of the inner ear: use of modified GRASS and fast spin-echo sequences

We report our experience with MRI of the normal and pathological inner ear with fast spin-echo and modified gradient recalled at steady state sequences. Although earlier studies on temporal bone MRI were discouraging, improvements in MR technology combined with the use of paramagnetic contrast media can make MRI a useful diagnostic tool for the assessment of inner ear pathology. Conventional spin-echo imaging seems not to be the modality of choice because of the relatively thick slices and the long acquisition times.