MR imaging of CNS involvement in children affected by chronic liver disease.

BACKGROUND AND PURPOSE: MR imaging sheds new light on CNS involvement in the course of acquired chronic liver disease; however, the exact pathogenetic mechanisms of hepatic encephalopathy and associated MR abnormalities remain unclear. Our purpose was to relate MR signal intensity abnormalities of the CNS to clinical, biochemical, and pathologic features of childhood-onset chronic liver disease. METHODS: Twenty-one patients (12 male and nine female patients) were included in the study; two had Crigler-Najjar disease type 2, 17 had chronic liver disease of different causes, and two had idiopathic copper toxicosis. Twelve patients had histologically proved liver cirrhosis, with a median disease duration of 175 months at the time of MR study. None had clinical symptoms of hepatic encephalopathy. MR imaging was performed using spin-echo T1- and T2-weighted sequences. RESULTS: Eleven patients had abnormal MR imaging findings of the brain revealed by T1-weighted MR sequences; two of the 11 had idiopathic copper toxicosis. The affected sites were the hypothalamus and globus pallidus, presenting symmetrical and bilateral high signal intensities, or the pituitary gland, which appeared homogeneously hyperintense, or both findings. Eight of the 12 patients with cirrhosis had abnormal MR signals of the brain. In these, the median cirrhosis duration was shorter (169 months) than in the remaining four patients with normal MR signals (177 months). A significant correlation was found between abnormal MR signals of the brain and cirrhosis (P = .008) and factor V activity (P = .008). CONCLUSION: MR imaging confirms the presence of abnormal brain signals in the globus pallidus, hypothalamus, and pituitary gland in patients with childhood-onset liver disease in the absence of clinical symptoms of encephalopathy. Signal intensity abnormalities are likely caused by an as yet unidentified metabolic process partially correlated with the severity of liver disease.

Magnetic resonance appearance of endometrial sarcoma: report of a case with unusual findings.

We report the MR findings of an endometrial stromal sarcoma. The uterus was enlarged and completely replaced by neoplastic tissue, with full-thickness myometrial infiltration. It had isointense signal on T1- and irregularly hyperintense signal on T2-weighted images and the dynamic study with intravenous gadoteridol showed centripetal enhancement. This sarcomatous-like pattern correlates well with the pathologic and CT findings reported in the literature.

The latest in ultrasound: three-dimensional imaging. Part II.

INTRODUCTION: The three-dimensional (3D) reconstruction of ultrasound images has become a widespread option in ultrasound equipment. Specific softwares have become available and 3D reconstruction feasible since the early 1990s, particularly since 1994. POSSIBLE CLINICAL APPLICATIONS: Several clinical applications are feasible in all parenchymatous organs (mainly the liver and prostate), hollow viscera (e.g. the bladder and gallbladder), peripheral vessels (supra-aortic trunks and limb vessels) and central (the aorta and iliac arteries) or cerebral vessels. Moreover, tumoral vessels in parenchymatous organs can be reconstructed, and even the fetus in the uterine cavity, with excellent detailing. The recent introduction of echocontrast agents and second harmonic imaging has permitted to study normal and abnormal peripheral, central and parenchymatous vessels, with similar patterns to those obtained with digital angiography. The spatial relationships between the vascular structures of the liver, kidney and placenta were studied with 3D ultrasound angiograms. The applications of this new technique include the analysis of vascular anatomy and the potential assessment of organ perfusion. THE LATEST APPLICATIONS--INTRAVASCULAR STUDIES: Some catheters with an ultrasound transducer in the tip have been tested for intravascular studies. Just like conventional transducers, they provide two-dimensional (2D) images which are then postprocessed into longitudinal 3D or volume reconstructions. The former resemble angiographic images and can be viewed 3D rotating the image along its longitudinal axis. Volume images, which are more complex and slower to obtain, can be rotated on any spatial plane and provide rich detailing of the internal vascular lumen. The clinical importance of intravascular ultrasound with 3D volume reconstructions lies in the diagnosis of vascular conditions and the assessment and monitoring of intravascular interventional procedures--e.g. to detect inaccurate deployment of intravascular stents and endoluminal grafts during the maneuver. Three-dimensional reconstructions involve geometric data assembly and volumetric interpolation of a spatially related sequence of tomographic cross sections generated by an ultrasound catheter withdrawn at a constant rate through a vascular segment of interest, resulting in the display of a straight segment. Therefore particular care is needed and there are some useful hints to avoid mistakes. CONCLUSIONS: Three dimensional reconstructions of B-mode and color Doppler images are no longer a work in progress and their clinical importance and possible applications are both established and ever-increasing. On the other hand, independent of the different types of energy used, also computed tomography and magnetic resonance 3D reconstructions are very useful from a clinical viewpoint and they have become an established routine technique for both these methods. It is very likely that 3D volume reconstructions in ultrasound will find numerous applications in the near future. They may help to increase the diagnostic confidence and to facilitate diagnosis, intraprocedure monitoring in interventional radiology and follow-up and also to reduce the number of invasive examinations with iodinated contrast agents. This could result in cutting the cost and duration of the most expensive examinations. New, although invasive, applications can be hypothesized for intravascular or intraluminal catheters with an ultrasound transducer inside.

Ultrasound contrast agents: basic principles.

INTRODUCTION: Ultrasonography lacked substances to be administered to patients to improve or increase the diagnostic yield, which is peculiar considering that contrast agents have long been used with all the other imaging techniques. Fortunately some contrast agents, most of them consisting in gas microbubbles, have been recently introduced for ultrasound imaging too: this review will focus on their history, behavior, current applications and future developments. Echocontrast agent research is in progress and many new agents are expected to be marketed this and next year, to be added to Levovist by Schering AG (Berlin, Germany), to enhance the ultrasound signal safely and effectively. No definitive conclusions can be drawn yet on the actual merits of each contrast agent, but all of them seem to be both effective and safe, meaning that their future success will depend on the relative cost-effectiveness and peculiarities. THE BASIC PRINCIPLES OF ECHOCONTRAST AGENTS: The microbubbles act as echo-enhancers by basically the same mechanism as that determining echo-scattering in all the other cases of diagnostic ultrasound, namely that the backscattering echo intensity is proportional to the change in acoustic impedance between the blood and the gas making the bubbles. The different acoustic impedance at this interface is very high and in fact all of the incident sound is reflected, even though not all of it will of course go back to the transducer. But the acoustic wave reflection, though nearly complete, would not be sufficient to determine a strong US enhancement because the microbubbles are very small and are sparse in the circulation. Moreover, reflectivity is proportional to the fourth power of a particle diameter but also directly proportional to the concentration of the particles themselves. SECOND HARMONIC IMAGING: As we said above, the microbubbles reached by an ultrasound signal resonate with a specific frequency depending on microbubble diameter. However, the main resonance frequency is not the only resonance frequency of the bubble itself and multiple frequencies of the fundamental one are emitted, just like in a musical instrument. These harmonic frequencies have decreasing intensity, but the second frequency, known as the second harmonic, is still strong enough to be used for diagnostic purposes. The theoretical advantage of the harmonic over the fundamental frequency is that only contrast agent microbubbles resonate with harmonic frequencies, while adjacent tissues do not resonate, or else their harmonic resonation is very little. Thus, using a unit especially set to produce ultrasounds at a given frequency (3.5 MHz) and receive an ultrasound signal twice as powerful (7 MHz) it will be possible to show the contrast agent only, without any artifact from the surrounding anatomical structures, with a markedly improved signal-to-noise ratio. A similar effect to digital subtraction in angiography can thus be obtained, even though through a totally different process. Moreover, second harmonic imaging permits to show extremely small vessels (down to 40 microm) with very slow flow, which would be missed with a conventional method. B-mode imaging can also depict the microbubbles in the myocardium suppressing nearly all the artifacts from cardiac muscle motion. Recently a peculiar behavior of microbubbles has been observed which may permit contrast agent detection even in capillaries. This method is variously known as sonoscintigraphy, loss of correlation, stimulated acoustic emission and transient scattering. The contrast agent microbubbles reached by an ultrasound beam powerful enough explode producing a strong and very short backscatter echo which is read by the unit as a Doppler signal and results in a color pixel where the individual microbubble exploded. CONCLUSIONS: The microbubble contrast agents developed and introduced as safe and effective echo-enhancers in present-day clinical practice will open up new oppurtunities

Contrast enhancing agents in ultrasonography: clinical applications.

INTRODUCTION: As ultrasound remains a poorly sensitive method, echocontrast agents make a real difference. At least 29 echocontrast agents are currently on trial worldwide; their chemical composition, mechanisms of action and possible clinical applications are different. The state of the art of echocontrast agents is discussed: their established applications, those expected in the near future and finally their hypothetical, ideal applications. POTENTIAL CLINICAL APPLICATIONS: An extravascular and a vascular domain can be considered. The former includes the gastrointestinal tract and body cavities--both the normal (bladder, uterus, tubes and so on) and the abnormal (abscesses, fistulas, pericardium, peritoneum and so on) ones. Echocontrast agents can: (1) create or improve an acoustic window; (2) distend some organs and fill them with a liquid, with homogenous attenuation of the ultrasound beam; (3) displace the air-containing intestinal loops; (4) depict the walls, the shape and the contours of a normal or abnormal cavity; (5) detect abnormal communications, fistulas and drainages; and (6) evaluate the amount of fluid in the pleural, pericardial or peritoneal cavities. As for vascular applications, this domain sees the highest number of echocontrast agents on trial or on the market. The best know of them are: Levovist (Schering AG, Berlin, Germany), BR1 (Bracco, Milan, Italy) and EchoGen (Abbott, USA). All these act by enhancing arteries, veins and capillaries. The clinical applications validated in clinical trials mainly regard studies in intracranial and neck vessels and the vascularity of upper and especially lower limbs of renal vessels. Tumor macrovascularity (and in the future, hopefully microvascularity) can also be studied in parenchymatous and/or glandular organs, as well as in intra- and extra-abdominal parenchymatous organs in the periskeletal soft tissues. Clinical validation has also been obtained in the follow-up of tumors submitted to ablation therapy (chemoembolization, ethanol injection, thermal ablation) and in echocardiography, both for morphological studies in the cardiac cavities and for the cardiac wall perfusion. CONCLUSIONS: In a subgroup of 513 out of 1275 patients examined Europe-wide, the contrast agent Levovist increased the diagnostic confidence from 27.4 +/- 22.5 to 77.2 +/- 22.5%. Such data encourage further trials to validate current preliminary results.

The clinical value of computed tomography and lymphography in detecting lymph node metastases from epithelial ovarian cancer.

We investigated the accuracy of both lymphography and computed tomography (CT) in detecting lymph node metastases in 58 patients with primary epithelial ovarian cancer (group a) and subsequently submitted to surgery including pelvic and/or lumbo-aortic lymphadenectomy. CT accuracy was also investigated in 41 patients with clinically suspected relapse of ovarian cancer (group b). In the first group (a) overall results in the pelvis were, respectively, for lymphography and CT: 94.8 vs 89.6% accuracy, 85.7 vs 57.1% sensitivity, 97.7 vs 100% specificity, 97.7 vs 100% positive predictive value and 95.5 vs 88% negative predictive value. In the lumbo-aortic region, we had: 88.8 vs 86.1% accuracy, 71.4 vs 64.2% sensitivity, 100% specificity and positive predictive value for both techniques, and 84.6 vs 81.6% negative predictive value. In the second group (b) CT accuracy, sensitivity and specificity were 90.2, 80 and 100%, respectively. CT, thanks to its high specificity and positive predictive value, can represent the method of choice for the evaluation of pelvic and lumbo-aortic lymph node metastases in untreated and relapsing ovarian cancer. CT demonstration of lymph node metastases can affect not only lesion staging, but also chemotherapy; different indications for lymphadenectomy may also depend on CT.

Progression from nodular to lymphangitic subcutaneous metastasis from clear cell endometrial carcinoma: CT findings.

Subcutaneous metastases from clear cell endometrial carcinoma are an uncommon event and tumor implantations are rarely found with diagnostic imaging techniques. The nodular form is the most frequent type of subcutaneous metastasis from genital system tumors, even though plaque-like and infiltrative forms have also been reported. We report the first case of subcutaneous metastasis from clear cell endometrial carcinoma whose progression from the early nodular to the lymphangitic infiltrative form was studied with computed tomography (CT). Differential diagnostic problems are discussed.

Spontaneous hemorrhage of a liver metastasis from squamous cell cervical carcinoma: case report and review of the literature.

Liver metastases are an uncommon cause of spontaneous bleeding compared with primary benign/malignant liver lesions. Since metastatic lesions tend to maintain the vascular characteristics of the primary tumor, some metastases have a greater proclivity for hemorrhage into the host organ than others. We describe the clinical and computed tomography (CT) features of a patient previously treated for nonkeratinizing small cell squamous carcinoma of the cervix uteri. As the metastatic rupture was diagnosed while still intraparenchymal and subcapsular, with minimal peritoneal reaction, the patient's outcome was favorable.

Extraperitoneal pelvic leiomyosarcoma. MR findings in a case.

The magnetic resonance imaging (MRI) of a patient with nongynecologic pelvic leiomyosarcoma is presented. A retroperitoneal mass appeared under the broad ligaments, in the right paravesical and parametrial, lateral pararectal site. The mass leaned on the uterus and vagina. On MRI, the mass had solid structure, isointense on T1-weighted images, inhomogeneously iperintense on T2-weighted images with central areas of increased intensity. Late after contrast agent administration, the mass appeared inhomogeneously ipointense with areas of fair late contrast enhancement. The morphology of the tumor, the retroperitoneal site, and MRI sequences make the differential diagnosis. These evidences were useful in treatment planning.

Blind megaureter with ipsilateral renal agenesis and mullerian anomaly: MR findings in a case.

The magnetic resonance imaging (MRI) of a patient with congenital blind megaureter and mullerian anomaly are presented. A retroperitoneal pelvic mass appeared as elongated tubular cystic structure spreading from parametrium to the adnexa and reaching the recto-sigma. On MRI, the mass was hyperintense on T1 and T2-weighted images and disappeared in STIR sequences. The mass with pseudo-intestinal structure, the retroperitoneal site, and the MRI sequences make the differential diagnosis.

Multiple nodular metastases in mesenteric panniculitis by uterine papillary serous adenocarcinoma (UPSC): CT appearance of a case.

Intra-abdominal panniculitis is a thickening of the mesentery of the small/large intestine due to infiltration of lipid-laden macrophages associated with a variable amount of fibrosis. This condition is rarely associated with malignant neoplasms. We report the computed tomography (CT) findings of a patient treated for uterine papillary serous adenocarcinoma (UPSC). She had mesenteric panniculitis where metastatic tumor nodules implanted. This was the only intraperitoneal recurrence. To our knowledge, no such finding has been reported in the gynecologic and radiologic literature to date. On CT images, the differential diagnosis is with cystic dilatations of mesenteric lymph vessels.

Magnetic resonance imaging in the study of ischemic heart disease.

In ischemic heart disease, as compared to other procedures, Magnetic Resonance Imaging (MRI) offers the advantage of providing in a single diagnostic session an ample and reliable multiparametric analysis. The technological advances of recent years have been increasing exponentially and marked qualitative refinements are thus predictable in the near future for morphological, functional, perfusional and metabolic studies.

Topical role and future perspectives of sonographic contrast agents in the differential diagnosis of solid thyroid lesions.

Gray scale sonography and US-guided biopsy are cost-effective and reliable procedures in the differential diagnosis of focal thyroid lesions. The frequent presence of multiple foci can make multiple biopsies intolerable to the patient. The use of a sonographic contrast agent (Levovist) composed of microbubbles was evaluated in the differential diagnosis of focal solid lesions of the thyroid. Time/intensity curves after bolus injection of contrast were studied with samplings at the level of focal lesions, extranodular parenchyma and common carotid in 29 lesions of 25 patients (16 females and 9 males) ranging in age 21 to 68 years. The evaluated parameters were: the curve morphology, the time to peak value, the mean enhancement time and the wash-in/out variate gamma curve. All focal lesions underwent biopsy. No significant differences were observed as for mean enhancement time while for time to peak values only two malignant lesions seemed to show values different from those of other solid lesions. Wash-in/out variate gamma curves seemed more interesting; they presented a dual morphology: 1) parenchymal for hyperplastic areas, pseudonodular neoformations during thyroiditis and healthy thyroid parenchyma, 2) vascular for malignant lesions and carotid lumen. Autonomous nodules showed an intermediate morphology. In spite of major limitations, the results seem to pave the way for additional possibilities of noninvasive differential diagnosis in the evaluation of focal solid thyroid lesions.

[Noninvasive evaluation of the left and right ventricular function using magnetic resonance]. / Valutazione non invasiva della funzione ventricolare sinistra e destra con Risonanza Magnetica.

MR imaging is one of the methods allowing the measurement of heart volumes. It provides oblique body sections along the cardiac axes according to cardiac anatomical planes and a spontaneous contrast between blood and myocardium. This study was aimed at evaluating the reliability of both ventricular volumes and ejection fraction measurement by applying the area-length method in patients with a normal left ventricle (group A, 13 patients), in patients with a dilated hypokinetic left ventricle (group B, 20 patients), in cases with segmental abnormalities of the kinesis of the left ventricle following myocardial infarction (group C, 15 patients) and in cases with pathologic involvement of the right ventricle alone for the calculation of the right ventricular ejection fraction (group D, 16 patients), as compared with ventriculography. Good correlations between MR ejection fraction and angiographic ejection fraction were observed in all groups (group A: r = 0.79, p less than 0.001; group B: r = 0.80, p less than 0.001; group C: r = 0.97, p less than 0.001; group D: r = 0.98, p less than 0.001). In the patients in groups A and D volumetric values were constantly underestimated, both telediastolic and telesystolic, due to both the partial volume effect and the cardiac rotation and translation during systole. MR imaging emerges as a reliable method which can easily be applied to the evaluation of left and right ventricular function even in routine examinations.

[Power Doppler in breast diseases: preliminary results]. / Il power Doppler nella senologia: risultati preliminari.

Since 1993, a new technique called power Doppler or color Doppler energy, based on Doppler signals, has been used to study the vascularization of various organs. Since power Doppler appears to permit better assessment of slow flow than color Doppler, we used this technique to study the vascularization of breast lesions. Seventy-five patients (age range: 33-81 years, mean: 53 years) were examined: 28 had simple or complex cysts, 4 cysts with internal echoes, 1 fibrocystic disease, 3 nodular fibrocystic disease, 12 fibroadenoma, 3 benign microcalcifications, 10 cancer, 3 scarring, 1 recurrent cancer, 7 axillary nodes; 3 young patients with no breast disease were also examined as a control group. All the patients were examined first with B-mode and then with color power Doppler; both during the exam and later on, in the study of similar sections, power Doppler signals were stronger and, in many cases, more numerous. Particularly, with power Doppler, in similar sections, 1-3 more signals were demonstrated in healthy women and 1-4 more signals in fibroadenomas with rich vascularization and in neoplasms, while in 2 cysts perilesional signals were demonstrated only with power Doppler. Color-Doppler semiology of breast lesions was confirmed. Thus, since the signals were stronger with power Doppler, we believe it to be a promising tool in the study of the vascularization of breast lesions which can provide useful diagnostic information as to lesion nature, the results of local treatment and the response to primary medical therapy, as well as in the study of axillary lymph nodes.

[The larynx: an anatomical and functional echographic study]. / La laringe: studio ecografico anatomico e funzionale.

PURPOSE: To investigate the capabilities of US in morphological and functional studies of laryngeal structures. MATERIALS AND METHODS: We examined 50 healthy subjects (30 women and 20 men) ranging in age 23 to 74 years; 17 of them were professional opera singers. The patient was laid supine, with his/her neck in marked hypertension, and images were acquired with the vocal cords at rest, and during quiet breathing inspiratory and expiratory standstill, Valsalva, and wording of "e" and "o". We used 7.5-12.0 MHz probes to perform (para)median axial scans with anteroposterior and caudocranial US beam incidence. RESULTS: All the anatomical structures that could be measured were clearly demonstrated. The length of the true vocal cords was 16-28 mm in women and 20-23 mm in men and their wideness 7-15 mm to the dorsal end 2-4 mm to the ventral and; maximum thickness ranged 2-10 mm. The respiratory space varies 2-8 mm in the different phases of respiration and speech. In the 17 opera singers we found agreement between length of the vocal cord compass: basses had 30-33 mm and tenors 21-25 mm. DISCUSSION AND CONCLUSIONS: In addition to the advantages US is known to provide, it can also permit accurate measurements of the anatomical structures of the larynx and respiratory space at rest and in the dynamic phase, which are important data in some conditions (e.g., cord paralysis) or follow-up of drug or rehabilitation treatment. Finally US can permit to detect atypical situations such as those in false/true vocal cords hypertrophy and abnormal cord growth.