Antonio Chiesa

Congenital absence of portal vein with nodular regenerative hyperplasia of the liver

Abstract. Congenital absence of the portal vein is a very rare anomaly. The intestinal and splenic venous drainage bypasses the liver and drain into the inferior vena cava (IVC). Two cases of such anomaly are described. Both cases were investigated by US coupled with echo-colour Doppler examination, CT and MR imaging, followed by digital subtraction angiography (DSA) and liver biopsy. In the first case the splenic and superior mesenteric vein formed a venous trunk which emptied directly into the IVC; in the second case, the splanchnic blood flowed into a dilated hepatofugal inferior mesenteric vein which connected to the left internal iliac vein. In both cases nodular regenerative hyperplasia of the liver was present, presumably due to an abnormal hepatic cell response to the absent portal flow. The particular contribution of MR imaging to the diagnosis of both vascular abnormalities and liver parenchyma derangement and its advantages over the other diagnostic techniques is emphasized. The clinical and radiological features of 17 previously reported cases are reviewed.

The pseudocapsule in hepatocellular carcinoma: correlation between dynamic MR imaging and pathology

Abstract. Nodular hepatocellular carcinoma (HCC) is characterized by the presence of a pseudocapsule (constructed usually from connective fibrous tissue) that appears hypointense on T1- and T2-weighted spin-echo (SE) and gradient-echo (GE) MR imaging sequences without a contrast medium. The presence of vascular structures inside the tumor, which are verified by histological exam, affects enhancement of the PC after administrating the contrast medium: The impregnation is more evident in the dynamic study but also persists on the delayed T1-weighted SE images. The accuracy of MR in detecting the pseudocapsule of HCC and contrast enhancement of the pseudocapsule during dynamic studies were evaluated and related to pathological findings. Thirty-seven HCC were examined in 33 patients and afterwards resected. In capsulated nodules, besides usual hematoxylin, eosin, and trichrome stainings, histochemical and immunohistochemical methods were performed. On a 1.5-T MR unit, T1- and T2-weighted SE and GE FLASH 2D sequences after intravenous injection of Gd-DTPA (dynamic study) were used. In a later phase, T1-weighted SE sequences were repeated. Histologically, the pseudocapsule (thickness 0.2–6 mm) was present in 26 of 37 nodules (70 %). The dynamic study was the most suitable technique to show the pseudocapsule, which was recognized in 80.7 % (21 of 26 nodules). In 5 of 26 cases, the pseudocapsule, not demonstrated by MR, was thinner than 0.4 mm. In 16 of 21 cases, in the early portal phase (30–60 s), the pseudocapsule had an early enhancement, which was more evident later; in 5 of 21 cases the enhancement was observed only in the late portal phase (1–2 min). At histological examination, 14 of 16 pseudocapsules with early enhancement showed a more prominent vasculature than those with enhancement in the equilibrium phase. Magnetic resonance was a reliable tool in demonstrating the pseudocapsule of HCC. The histological examination demonstrated a good correlation between the enhancement behavior and the vessel number of the pseudocapsule.

MRI of focal nodular hyperplasia (FNH) with gadobenate dimeglumine (Gd-BOPTA) and SPIO (ferumoxides): An intra-individual comparison

To compare the efficacy of two different MR contrast agents for the detection and diagnosis of focal nodular hyperplasia (FNH).

MR of malignant nasosinusal neoplasms frequently asked questions

This paper focuses on the role of MR imaging of malignant neoplasms through a particular layout that emphasizes: (a) the rationale for the application of imaging; (b) the factors influencing the selection of sequences, planes and their proper arrangement; (c) the correlation between MR findings, imaging staging and clinical decision making. Since in most cases surgery is the treatment of choice, the precise assessment of the local extent and spread of tumour plays a key role in planning the surgical approach and influences either the therapy and the prognosis. However, the degree of spatial/anatomical detail required in treatment planning significantly differs between surgery and radiotherapy. Planning of the examination technique focuses on: (a) assembling sequences and planes in the shortest time possible; (b) the solution of specific problems: distinction between neoplasm and retained secretions within nasosinusal cavities; staging of submucosal spread toward the anterior cranial fossa, the orbit, the pterygo-palatine and superior orbital fissures. Since the most effective barrier to spread of neoplasms beyond sinusal walls does not depend on the mineral content of bone, but on the periosteum, assessment of the integrity of periorbita or dura mater is an essential information. Although MR cannot detect focal erosions of the thin sinusal walls, it reliably demonstrates both residual barriers (periorbita and dura), even though the bone has been completely destroyed. However, the final decision concerning orbital exenteration is made according to intraoperative staging. MR imaging can accurately precise the degree of anterior cranial fossa involvement. Furthermore, since either MR and CT accurately indicate the need to perform an anterior craniofacial resection and adequately exclude neoplastic invasion requiring orbital exenteration, more comparative studies are required to demonstrate that MR preoperative staging of nasosinusal malignancies is cost-effective.

CT appearance of the larynx after conservative and radical surgery for carcinomas

Abstract. The purpose of this study was to evaluate the normal CT appearance of the larynx after conservative and radical surgery. Postoperative (conservative surgery n = 52, radical surgery n = 21) CT examinations of 73 patients suspected of local/regional recurrence (n = 53) or asymptomatic (n = 20) were retrospectively analysed. The CT findings of 45 patients negative at biopsy were utilised to assess the normal appearance after surgery. Changes in the laryngeal framework represented constant landmarks, whereas the variety of soft tissues resection often resulted in a more unpredictable appearance of the neolarynx. Considerable thickening of the mucosa covering the arytenoid cartilage(s) has been detected after horizontal supraglottic laryngectomy (40 %) or supracricoid laryngectomies (SL; 100 %). A “pseudocord” due to scar tissue appeared to be a constant finding following vertical haemilaryngectomy, frequently after SL. Dilation of a lateral recess of the hypopharynx was observed after SL. This “pharyngeal pouch” had considerable size and air or liquid content. The most frequent CT findings among 28 tumours recurrent after conservative or total surgery were a mass larger than 10 mm spreading beyond the larynx (63.1 %), thickening of anterior commissure (57.9 %), erosion of residual cartilages (16.9 %). Although CT detected one subclinical recurrence, its employment is justified only to assess the submucosal extent of the lesion. This requires a thorough knowledge of normal postoperative findings.

Hypervascular hepatic lesions: dynamic and late enhancement pattern with Gd-BOPTA.

It is not always possible to accurately diagnose the nature of a given lesion as different lesion types often have similar enhancement/behavior patterns on CT or MRI (1). Moreover, the frequent atypical appearance of certain lesion types (e.g. FNH) might further complicate the diagnosis (2–5). Gadobenate dimeglumine (MultiHance®, Gd-BOPTA/ Dimeg; Bracco SpA, Milan, Italy) is a paramagnetic, gadolinium-based contrast agent which has a vascular-interstitial distribution in the first few minutes after injection. It has a dual route of elimination with approximately 96% of the injected dose eliminated renally (similar to that of other available gadolinium agents) and the remaining 2 to 4% taken up by functioning hepatocytes and eliminated with the bile, giving rise to a marked and prolonged increase in liver parenchymal signal intensity. The aim of the present study was to determine whether gadobenate dimeglumine is able to provide additional information for the improved characterization of hypervascular focal liver lesions.

Computed tomography scanning of supraglottic neoplasms: Its cost-effective use in preoperative staging†

Acad Radio11996;3:

Evaluating the Digital Storage Requirements for a Partial Picture Archive and Communication System

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Angiomyolipoma in a Patient with Tuberous Sclerosis

59 9 1996, Association of University Radiologists C omputed tomography (CT) scanning has become the accepted imaging 9 standard for mapping submucosal spread of laryngeal neoplasms, significantly improving the accuracy of preoperative staging [1]. However, its clinical efficacy in predicting the feasibility of conservative surgery of supraglottic neoplasms has not been completely proved [2]. The purpose of this retrospective study was to assess the role of CT scanning in the selection of treatment of supraglottic neoplasms (partial versus total laryngectomy) and to evaluate its cost-effectiveness compared with clinical staging.

Focal Liver Lesions: Evaluation of the Efficacy of Gadobenate Dimeglumine in MR Imaging—A Multicenter Phase III Clinical Study

The study evaluates the volume of digital images produced in a department of diagnostic imaging, with the primary goal of identifying, the requirements of digital storage for a partial picture archive and communication system (PACS). The daily activity of digital units (one computed tomography unit, one magnetic resonance imaging, two ultrasonography, and one digital subtraction angiography), which perform 25% of total examinations in the department, was analyzed to determine the number of images produced by digital techniques. They account for 65% to 70% of the total images. The storage capacity necessary to contain all digital data produced in a 800-bed hospital reaches nearly 100 Gbyte/yr without compression. The study emphasizes that a partial PACS can be economically justified through reduced film-archiving costs. This goal could be achieved through a selection of significant images and examinations, considerably reducing the cost of film reproduction and allowing the amortization of a partial PACS in about 5 or 6 years.