ESGAR consensus statement on liver MR imaging and clinical use of liver-specific contrast agents.

OBJECTIVES: To develop a consensus and provide updated recommendations on liver MR imaging and the clinical use of liver-specific contrast agents. METHODS: The European Society of Gastrointestinal and Abdominal Radiology (ESGAR) formed a multinational European panel of experts, selected on the basis of a literature review and their leadership in the field of liver MR imaging. A modified Delphi process was adopted to draft a list of statements. Descriptive and Cronbach's statistics were used to rate levels of agreement and internal reliability of the consensus. RESULTS: Three Delphi rounds were conducted and 76 statements composed on MR technique (n = 17), clinical application of liver-specific contrast agents in benign, focal liver lesions (n = 7), malignant liver lesions in non-cirrhotic (n = 9) and in cirrhotic patients (n = 18), diffuse and vascular liver diseases (n = 12), and bile ducts (n = 13). The overall mean score of agreement was 4.84 (SD ±0.17). Full consensus was reached in 22 % of all statements in all working groups, with no full consensus reached on diffuse and vascular diseases. CONCLUSIONS: The consensus provided updated recommendations on the methodology, and clinical indications, of MRI with liver specific contrast agents in the study of liver diseases. KEY POINTS: • Liver-specific contrast agents are recommended in MRI of the liver. • The hepatobiliary phase improves the detection and characterization of hepatocellular lesions. • Liver-specific contrast agents can improve the detection of HCC.

iPad-based primary 2D reading of CT angiography examinations of patients with suspected acute gastrointestinal bleeding: preliminary experience.

OBJECTIVE: To evaluate the effectiveness of the iPad (Apple Inc., Cupertino, CA) for two-dimensional (2D) reading of CT angiography (CTA) studies performed for suspected acute non-variceal gastrointestinal bleeding. METHODS: 24 CTA examinations of patients with suspected acute gastrointestinal bleeding confirmed (19/24, 79.2%) or ruled out (5/24, 20.8%) by digital subtraction angiography (DSA) were retrospectively reviewed by three independent readers on a commercial picture archiving communication system (PACS) workstation and on an iPad with Retina Display® 64 GB (Apple Inc.). The time needed to complete reading of every CTA examination was recorded, as well as the rate of detection of arterial bleeding and identification of suspected bleeding arteries on both devices. RESULTS: Overall, the area under the receiver operating characteristic curve, sensitivity, specificity, positive- and negative-predictive values for bleeding detection were not significantly different while using the iPad and workstation (0.774 vs 0.847, 0.947 vs 0.895, 0.6 vs 0.8, 0.9 vs 0.944 and 0.750 vs 0.667, respectively; p > 0.05). In DSA-positive cases, the iPad and workstation allowed correct identification of the bleeding source in 17/19 cases (89.5%) and 15/19 cases (78.9%), respectively (p > 0.05). Finally, the time needed to complete reading of every CTA study was significantly shorter using the iPad (169 ± 74 vs 222 ± 70 s, respectively; p < 0.01). CONCLUSION: Compared with a conventional PACS workstation, iPad-based preliminary 2D reading of CTA studies has comparable diagnostic accuracy for detection of acute gastrointestinal bleeding and can be significantly faster. ADVANCES IN KNOWLEDGE: The iPad could be used by on-call interventional radiologists for immediate decision on percutaneous embolization in patients with suspected acute gastrointestinal bleeding.

Randomised controlled trial of doxorubicin-eluting beads vs conventional chemoembolisation for hepatocellular carcinoma.

BACKGROUND: Transcatheter arterial chemoembolisation (TACE) is the treatment of choice for intermediate stage hepatocellular carcinoma (HCC). Doxorubicin-loaded drug-eluting beads (DEB)-TACE is expected to improve the performance of conventional TACE (cTACE). The aim of this study was to compare DEB-TACE with cTACE in terms of time-to-tumour progression (TTP), adverse events (AEs), and 2-year survival. METHODS: Patients were randomised one-to-one to undergo cTACE or DEB-TACE and followed-up for at least 2 years or until death. Transcatheter arterial chemoembolisation was repeated 'on-demand'. RESULTS: We enrolled 177 patients: 89 underwent DEB-TACE and 88 cTACE. The median number of procedures was 2 in each arm, and the in-hospital stay was 3 and 4 days, respectively (P=0.323). No differences were found in local and overall tumour response. The median TTP was 9 months in both arms. The AE incidence and severity did not differ between the arms, except for post-procedural pain, more frequent and severe after cTACE (P<0.001). The 1- and 2-year survival rates were 86.2% and 56.8% after DEB-TACE and 83.5% and 55.4% after cTACE (P=0.949). Eastern Cooperative Oncology Group (ECOG), serum albumin, and tumour number independently predicted survival (P<0.05). CONCLUSIONS: The DEB-TACE and the cTACE are equally effective and safe, with the only advantage of DEB-TACE being less post-procedural abdominal pain.

Efficacy and safety of combination therapy with everolimus and sorafenib for recurrence of hepatocellular carcinoma after liver transplantation.

BACKGROUND: Recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) is still associated with a dismal outcome. Combination therapy with everolimus (EVL) and vascular endothelial growth factor inhibitor sorafenib (SORA) is based on the role of both b-Raf and mammalian target of rapamycin/protein kinase B pathways in the pathogenesis of HCC and is being investigated in clinical practice. METHODS: This was a single-center retrospective analysis on LT recipients with unresectable HCC recurrence and undergoing combination therapy with EVL and SORA. Patients were included if they were switched to EVL+SORA at any time after surgery. Primary endpoint was overall survival (OS) after both LT and recurrence, and response to treatment based on the modified Response Evaluation Criteria in Solid Tumors (mRECIST) in the intention-to-treat (ITT) population. Secondary analysis was safety of combination therapy with EVL and SORA in the population of patients who received ≥1 dose of the study drug. RESULTS: Seven patients (100% male; median age 53 years [interquartile range (IQR) 9 years]) were considered for analysis. HCC recurrence was diagnosed at a median (IQR) interval since LT of 9 (126) months, and patients were administered EVL+SORA at a median interval since LT of 11 (126) months. Baseline immunosuppression was with tacrolimus (TAC) in 2 patients (28.6%), cyclosporine (CsA) in 2 (28.6%), and EVL monotherapy in 3 (42.8%). At a median (IQR) follow-up of 6.5 (14) months, 5 patients (71.4%) were alive, 4 of them (57.1%) with tumor progression according to the mRECIST criteria. Median (IQR) time to progression was 3.5 (12) months. Two patients died at a median (IQR) follow-up of 5 (1) months owing to tumor progression in 1 patient (14.3%) and sepsis in the other (14.3%). EVL monotherapy was achieved in 6 patients (85.7%), whereas 1patient (14.3%) could not withdraw from calcineurin inhibitor owing to acute rejection. Treatment complications were: hand-foot syndrome in 5 patients (71.4%), hypertension in 1 (14.3%), alopecia in 1 (14.3%), hypothyroidism in 1 (14.3%), diarrhea in 2 (28.6%), pruritus in 1 (14.3%), abdominal pain in 1 (14.3%), rash in 1 (14.3%), asthenia in 3 (42.8%), anorexia in 3 (42.8%), and hoarseness in 2 (28.6%). Adverse events led to temporary SORA discontinuation in 2 patients (28.6%) and to SORA dose reduction in 3 (42.8%). CONCLUSIONS: Treatment of HCC recurrence after LT with a combination regimen of EVL+ SORA is challenging because of SORA-related complications. Longer follow-up periods and larger series are needed to better capture the impact of such combination treatment on tumor progression and patient survival.

Diagnostic accuracy of CT colonography in patients with positive faecal occult blood test: results of the Italian project Legatumori 2003-2006.

PURPOSE: In the framework of the 3-year project of the Italian Legatumori (2003-2006), we evaluated the diagnostic accuracy of computed tomography (CT) colonography in detecting colorectal lesions in a screening population with positive faecal occult blood test (FOBT). MATERIALS AND METHODS: Two hundred and thirty asymptomatic subjects (age range 45-80 years) were enrolled in the study. CT colonography was performed with standard patient preparation (no faecal tagging) and a 4-detector-row CT scanner. Image analysis was carried out with primary 2D analysis and the use of 3D endoluminal views to solve difficult cases. Patients were referred for conventional colonoscopy in the following situations: detection of three or more suspected lesions with maximum diameter6 mm; presence of colonic masses (maximum diameter>3 cm). RESULTS: CT colonography detected colonic masses in 12 out of 135 subjects (8%). It generated 93 false positives and 19 false negatives in the identification of diminutive lesions (6 mm. Sensitivity was 83% in smaller lesions and 93% in lesions>6 mm; specificity was 45% and 59%, respectively. CONCLUSIONS: In a screening population with positive FOBT, CT colonography without faecal tagging and no definite size threshold for the reporting of polyps showed very low specificity but high sensitivity in the detection of all colorectal lesions.

Secretin-stimulated multi-detector CT versus mangafodipir trisodium-enhanced MR imaging plus MRCP in characterization of non-metastatic solid pancreatic lesions.

BACKGROUND AND AIM: Our study was aimed to compare multiphasic multi-detector computed tomography after secretin stimulation and mangafodipir trisodium-enhanced magnetic resonance imaging plus MR cholangiopancreatography in the characterization of solid pancreatic lesions. PATIENTS AND METHODS: Forty patients with ultrasound diagnosis of solid pancreatic lesion prospectively underwent both multi-detector computed tomography and magnetic resonance imaging. Three minutes after intravenous administration of secretin, post-contrast computed tomography scans were performed 40, 80, and 180 s after contrast medium injection. MR protocol included axial/coronal, thin/thick-slab, single-shot T2 w sequences and axial/coronal T1 w breath-hold spoiled gradient-echo images before and 30-40 min after intravenous infusion of manganese dipyri-doxal diphosphate. Different observers blindly evaluated the ability of computed tomography and magnetic resonance imaging to characterize focal pancreatic lesions. Surgery, biopsy, and/or follow-up were considered as our diagnostic gold standard. RESULTS: Thirty-five focal pancreatic lesions (adenocarcinoma, n=18; focal chronic pancreatitis, n=4; endocrine tumor, n=6; metastasis, n=1; cystic tumor, n=3; indeterminate cystic lesions, n=3) were present in 34 patients since the remaining 6 subjects showed no pathological finding. Both multi-detector computed tomography and magnetic resonance imaging showed a statistically significant correlation with the gold standard and between themselves in the characterization of 29 solid lesions of the pancreas (p<0.05). CONCLUSION: Both imaging techniques well correlate to final diagnosis of non-metastatic solid pancreatic lesions and particularly of adenocarcinomas with a slight advantage for mangafodipir trisodium-enhanced magnetic resonance imaging plus MR cholangiopancreatography.

CT colonography: Project of High National Interest No. 2005062137 of the Italian Ministry of Education, University and Research (MIUR).

PURPOSE: The aim of this paper is to describe the Web site of the Italian Project on CT Colonography (Research Project of High National Interest, PRIN No. 2005062137) and present the prototype of the online database. MATERIALS AND METHODS: The Web site was created with Microsoft Office Publisher 2003 software, which allows the realisation of multiple Web pages linked through a main menu located on the home page. The Web site contains a database of computed tomography (CT) colonography studies in the Digital Imaging and Communications in Medicine (DICOM) standard, all acquired with multidetector-row CT according to the parameters defined by the European Society of Abdominal and Gastrointestinal Radiology (ESGAR). The cases present different bowel-cleansing and tagging methods, and each case has been anonymised and classified according to the Colonography Reporting and Data System (C-RADS). RESULTS: The Web site is available at http address www.ctcolonography.org and is composed of eight pages. Download times for a 294-Mbyte file were 33 min from a residential ADSL (6 Mbit/s) network, 200 s from a local university network (100 Mbit/s) and 2 h and 50 min from a remote academic site in the USA. The Web site received 256 accesses in the 22 days since it went online. CONCLUSIONS: The Web site is an immediate and up-to-date tool for publicising the activity of the research project and a valuable learning resource for CT colonography.

Differential activation of mitogen-activated protein kinase signalling pathways in the hippocampus of CRND8 transgenic mouse, a model of Alzheimer's disease.

Transgenic Centre for Research in Neurodegenerative Diseases 8 (TgCRND8) mice expressing a double mutant form of human amyloid precursor protein represent a good model of Alzheimer's disease, and can be useful to clarify the involvement of mitogen-activated protein kinases (MAPK) dysregulation in the pathophysiology of this neurodegenerative disorder. Activation of extracellular regulated kinase (ERK) 1/2, jun kinase (JNK) and p38MAPK was studied in the hippocampus of 7-month-old TgCRND8 mice by immunohistochemistry and Western blot analysis using antibodies selective for the phosphorylated, and thus active, forms of the enzymes. We demonstrated that the three main MAPK pathways were differentially activated in cells of the hippocampus of TgCRND8 mice in comparison to wild type (Wt) littermates, p38MAPK and JNK being more activated, while ERK less activated. p38MAPK was significantly activated in microglia, astrocytes and neurons, around and distant from the plaques. JNK was highly activated in cells closely surrounding the plaques. No difference was observed in the activation of the two major bands of JNK, at a molecular weight of 46 kDa and 54 kDa. These data indicate the possible involvement of p38MAPK and JNK pathways dysregulation in the pathogenesis of Alzheimer's disease. The ERK2 isoform of the ERK pathway was less activated in the hippocampal dentate gyrus of Tg mice in basal conditions. Furthermore activation of the ERK pathway by ex vivo cholinergic stimulation with carbachol caused significantly higher activation of ERK in the hippocampus of Wt mice than in Tg mice. These findings may pose a molecular basis for the memory disruption of Alzheimer's disease, since proper functioning of the basal forebrain cholinergic neurons and of ERK2 is critical for memory formation.

Diffusion-weighted imaging in patients with progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system due to JC polyoma virus infection of oligodendrocytes. PML develops in patients with impaired T-cell function as occurs in HIV, malignancy or immunosuppressive drugs users. Until now no imaging methods have been reported to correlate with clinical status. Diffusion-weighted imaging (DWI) is a robust MRI tool in investigating white matter architecture and diseases. The aim of our work was to assess diffusion abnormalities in focal white matter lesions in patients with PML and to correlate the lesion load measured with conventional MRI and DWI to clinical variables. We evaluated eight patients with a biopsy or laboratory-supported diagnosis of PML. All patients underwent MRI including conventional sequences (fluid attenuated inversion recovery-FLAIR) and DWI. Mean diffusivity (MD) maps were used to quantify diffusion on white matter lesions. Global lesion load was calculated by manually tracing lesions on FLAIR images, while total, central core and peripheral lesion loads were calculated by manually tracing lesions on DWI images. Lesion load obtained with the conventional or DWI-based methods were correlated with clinical variables such as disease duration, disease severity and survival. White matter focal lesions are characterized by a central core with low signal on DWI images and high MD (1.853 x 10(-3) mm2/s), surrounded by a rim of high signal intensity on DWI and lower MD (1.1 x 10(-3) mm2/s). The MD value of normal-appearing white matter is higher although not statistically significant (0.783 x 10(-3) mm2/s) with respect to control subjects (0.750 x 10(-3) mm2/s). Inter-rater correlations of global lesion load between FLAIR (3.96%) and DWI (3.43%) was excellent (ICC=0.87). Global lesion load on FLAIR and DWI correlates with disease duration and severity (respectively, p=0.037, p=0.0272 with Karnofsky scale and p=0.0338 with EDSS on FLAIR images; p=0.043, p=0.0296 with Karnofsky scale and p=0.0365 with EDSS on DW images). Central core lesion load on DWI correlates with disease duration and severity (respectively p=0.043, p=0.0103 with Karnofsky scale and p=0.0112 with EDSS), while peripheral lesion load does not correlate with any clinical variable. The global lesion load in PML correlates with disease duration and severity. DWI images, which can distinguish within lesions a central core from a peripheral rim, reveal that a larger central core component correlates to a worsened clinical status and longer disease duration. On the other hand the peripheral rim lesion load visualized on DWI images does not correlate with clinical variables and does not achieve obtaining further prognostic information with respect to conventional imaging.

Multidetector CT in diagnostic work-up of patients with primary hyperparathyroidism.

PURPOSE: This study was performed to evaluate the accuracy of multidetector computed tomography (MDCT) in detecting parathyroid lesions in patients with primary hyperparathyroidism. MATERIALS AND METHODS: We included 60 patients with primary hyperparathyroidism. Preoperative first-line examinations revealed negative and doubtful ultrasound (US) findings in 34 and 26 cases, respectively, and negative, doubtful and positive scintigraphic findings in 19, 20 and 21 cases, respectively. CT findings were compared with the surgical results. RESULTS: CT examination was positive in 35 cases, negative in 15 cases and doubtful in ten cases. Forty out of 60 patients underwent surgery, and 39 lesions (37 adenomas, two primary hyperplasias) were identified. Surgery was negative in two cases. In eight cases, lesions had ectopic location. Surgery confirmed the CT findings in 23 positive cases. In 8/10 doubtful cases, surgery confirmed the location of the lesion in five cases, identified the ectopic location of lesions in two cases, and was negative in one case. In 9/15 cases with negative CT findings, surgery identified the lesion in eight cases. Sensitivity, specificity and diagnostic accuracy values were 78%, 25% and 73%, respectively. CONCLUSIONS: MDCT is an accurate second-line diagnostic technique in the detection of parathyroid lesions, allowing exploration of the entire cervical and mediastinal regions.

Assessment of midbrain atrophy in patients with progressive supranuclear palsy with routine magnetic resonance imaging.

OBJECTIVES: To assess midbrain atrophy through morphometric (linear, surface and volumetric) measurements in patients with clinically diagnosed progressive supranuclear palsy (PSP) and to establish the most accurate measure to be implemented in routine magnetic resonance (MR) protocol in distinguishing PSP from healthy subjects and MSA-p (multiple system atrophy, parkinsonian form) patients. MATERIALS AND METHODS: We studied 15 patients with the diagnosis of probable PSP, seven patients with the diagnosis of probable MSA-p and 14 age-matched healthy volunteers. MR protocol includes a sagittal SE T1-weighted sequence for cross-sectional area and linear brainstem measurements and a 3D-FSPGR sequence for brainstem volume measurements. RESULTS: A highly significant difference in the antero-posterior midbrain diameter, area and volume in PSP compared with control subjects was found. Only a measurement of the midbrain area and pons area enabled one to distinguish between PSP and MSA-p. Receiver operating characteristic analysis revealed that the midbrain area has the highest diagnostic accuracy in distinguishing between PSP and other conditions, with a sensitivity of 100% and specificity of 90.5%. The addition of the midbrain area/pons area ratio (A(ms)/A(pn) ratio) measurement improves the specificity in distinguishing between PSP and MSA. CONCLUSIONS: Morphological indexes indicate midbrain atrophy in PSP patients The combination of the A(ms) and A(ms)/A(pn) ratio measurements allows to discriminate between PSP and other conditions.

Quantitative diffusion-weighted MR imaging in the differential diagnosis of breast lesion.

The role of diffusion-weighted magnetic resonance imaging (DWI) to differentiate breast lesions in vivo was evaluated. Sixty women (mean age, 53 years) with 81 breast lesions were enrolled. A coronal echo planar imaging (EPI) sequence sensitised to diffusion (b value=1,000 s/mm(2)) was added to standard MR. The mean diffusivity (MD) was calculated. Differences in MD among cysts, benign lesions and malignant lesions were evaluated, and the sensitivity and specificity of DWI to diagnose malignant and benign lesions were calculated. The diagnosis was 18 cysts, 21 benign and 42 malignant nodules. MD values (mean +/- SD x 10(-3) mm(2)/s) were (1.48 +/- 0.37) for benign lesions, (0.95 +/- 0.18) for malignant lesions and (2.25 +/- 0.26) for cysts. Different MD values characterized different malignant breast lesion types. A MD threshold value of 1.1 x 10(-3) mm(2)/s discriminated malignant breast lesions from benign lesions with a specificity of 81% and sensitivity of 80%. Choosing a cut-off of 1.31 x 10(-3) mm(2)/s (MD of malignant lesions -2 SD), the specificity would be 67% with a sensitivity of 100%. Thus, MD values, related to tumor cellularity, provide reliable information to differentiate malignant breast lesions from benign ones. Quantitative DWI is not time-consuming and can be easily inserted into standard clinical breast MR imaging protocols.

Contrast-enhanced MR imaging in patients with BI-RADS 3-5 microcalcifications.

PURPOSE: The aim of this study was to evaluate the role of magnetic resonance imaging (MRI) in patients with microcalcifications classed as Breast Imaging Reporting and Data Systems (BI-RADS) 3-5. MATERIALS AND METHODS: Fifty-five patients with mammographic microcalcifications classified as BI-RADS categories 3, 4 or 5 underwent MRI and biopsy with stereotactic vacuum-assisted biopsy (VAB). Our gold standard was microhistology in all cases and histology with histological grading in patients who underwent surgery. Patients with a microhistological diagnosis of benign lesions underwent mammographic follow-up for at least 12 months. MRI was performed with a 1.5-Tesla (T) unit, and T1 coronal three-dimensional (3D) fast low-angle shot sequences were acquired before and after injection of paramagnetic contrast agent (0.1 mmol/kg). MRI findings, according to the Fisher score, were classified into BI-RADS classes. In patients with cancer who underwent surgery, we retrospectively compared the extension of the mammographic and MRI findings with histological extension. RESULTS: Histology revealed 26 ductal in situ cancers (DCIS) and ductal microinvasive cancers (DCmic), three atypical ductal hyperplasias (ADH) and 26 benign conditions. Histological grading of the 26 patients with cancer revealed four cases of G1, 11 cases of G2 and 11 cases of G3. If we consider mammographic BI-RADS category 3 as benign and BI-RADS 4 and 5 as malignant, mammography had 77% sensitivity, 59% specificity, 63% positive predictive value (PPV), 74% negative predictive value (NPV) and 67.2% diagnostic accuracy. If we consider MRI BI-RADS categories 1, 2 and 3 as benign and 4 and 5 as malignant, MRI had 73% sensitivity, 76% specificity, 73% PPV, 76% NPV and 74.5% diagnostic accuracy. As regards disease extension, mammography had 45% sensitivity and MRI had 84.6% sensitivity. CONCLUSION: Mammography and stereotactic biopsy still remain the only techniques for characterising microcalcifications. MRI cannot be considered a diagnostic tool for evaluating microcalcifications. It is, however, useful for identifying DCIS with more aggressive histological grades. An important application of MRI in patients with DCIS associated with suspicious microcalcifications could be to evaluate disease extension after a microhistological diagnosis of malignancy, as it allows a more accurate presurgical planning.

Value of image fusion in the staging of prostatic carcinoma.

PURPOSE: We assessed the value of image fusion in the staging of prostatic cancer in a series of 32 patients who underwent preoperative evaluation with transrectal colour-Doppler ultrasonography (TRUS) and magnetic resonance imaging (MRI). MATERIALS AND METHODS: Colour-Doppler TRUS exams were performed using a 7.5-MHz biplanar probe. MRI exams were done with a scanner operating at 1.5 Tesla (T) using an endorectal coil. All patients underwent radical prostatectomy within 2 weeks from the imaging assessment. Whole-mount sections were prepared from the surgical specimens and were subsequently digitised by using a high-resolution scanner. The Digital Imaging and Communications in Medicine (DICOM) TRUS and MR images as well as the digitised pathological images were transferred to a graphic workstation to perform image fusion. RESULTS: Image fusion was technically possible in 25/32 cases in which axial TRUS images were available. The following fusion images were obtained: TRUS + pathological sections; MRI + pathological sections; TRUS + MRI + pathological sections. The final pathological staging concerning the T status was: four pT2b, fourteen pT2c, three pT3a and four pT3b. The three types of image fusion led to the following results: TRUS + pathological sections, correct staging in 20/25 cases (accuracy 80%); MRI + pathological sections, correct staging in 22/25 cases (accuracy 88%); TRUS + MRI + pathological sections, correct staging in 23/25 cases (accuracy 92%). CONCLUSIONS: Our study suggests that by using image fusion between colour-Doppler TRUS and endorectal MRI, it is possible to improve the accuracy of pathological staging in patients who are candidates for radical prostatectomy.

How to differentiate liver lesions in cirrhosis.

The diagnosis of hepatocellular carcinoma is based on imaging examinations in combination with clinical and laboratory findings. Despite technological advances, imaging cirrhotic patients remains a challenging issue, since preneoplastic hepatocellular lesions, such as dysplastic nodules, mimic a small hepatocellular carcinoma. One of the key pathologic factors for differential diagnosis that is reflected in imaging appearances is the vascular supply to the lesion. It is accepted that imaging techniques may establish the diagnosis of hepatocellular carcinoma in nodules larger than 1 cm showing arterial hypervascularization and venous wash-out. In lesions that do not show a typical pattern, biopsy is still recommended. Contrast-enhanced ultrasound, spiral computed tomography or dynamic magnetic resonance imaging are required for characterization of lesions in cirrhotic liver. However, during the development of hepatocellular carcinoma, significant histological changes are present with or without an evident arterial supply of the nodule. Due to the ability of magnetic resonance to investigate differences in soft tissues and to exploit the properties of tissue-specific contrast agents, this imaging modality is particularly useful in the demonstration of the pathologic changes that take place at the histological level and at the level of the biliary and reticuloendothelial systems during carcinogenetic process in liver cirrhosis.

IERAPSI project: simulation of a canal wall-up mastoidectomy.

Among the various EU research projects concerning the medical application of virtual reality, the project Ist-1999-12175, called IERAPSI (Integrated Environment for the Rehearsal and Planning of Surgical Interventions), specifically addressed the creation of a virtual and interactive surgical field for the temporal bone using three-dimensional images derived from CT data. We report on the experience obtained in the IERAPSI project in simulating a canal wall-up mastoidectomy. A surgeon with extensive experience in surgery of the petrous bone performed the mastoidectomy. The operative field included the mastoid, with its substantial differences in density between the cortex and the pneumatized bone, together with soft tissue structures, both on the border and inside the bone. The simulation is better in the first part of the operation than in the second part, suffering from a lack of haptic feedback from soft tissue and the surgical tool in deeper contexts, and under-representation of the variability inherent in pneumatized bone. This said, the excellent representation of dust production and removal, 3D simulation through color, and very good visual and haptic feedback in the early stage of the procedure are impressive. IERAPSI represents a potential surgical planning theater for the training of students and young surgeons, but is also expected to aid expert surgeons in the preoperative planning of difficult cases.

CT colonography: contrast enhancement of benign and malignant colorectal lesions versus fecal residuals.

We retrospectively reviewed the computed tomographic colonographic datasets of 22 patients. Mean attenuation values of benign polyps before and after contrast administration were 30 +/- 15 HU and 90 +/- 18 HU, respectively. Mean attenuation values of colorectal cancer before and after contrast administration were 43 +/- 15 HU and 124 +/- 18 HU, respectively. The mean attenuation value of solid fecal residuals was 43 +/- 15 HU. The difference in attenuation value between precontrast and postcontrast studies of polyps was statistically significant (mean 60 HU, p < 0.01); the same was true for colorectal cancer (mean 81 HU, p < 0.01). The difference between postcontrast density of polyps and cancer with respect to density of solid fecal residuals was statistically significant (p < 0.01). The use of contrast medium could be of help in computed tomographic colonography for discriminating polypoid benign lesions and colorectal cancer from fecal residuals.

Multi-detector computed tomography angiography of the hepatic artery in liver transplant recipients.

PURPOSE: To evaluate the ability of multi-detector row computed tomography angiography (CTA) in detecting hepatic artery complications in the follow-up of liver transplant patients, performing volume-rendering as reconstruction technique. MATERIAL AND METHODS: The anatomy of hepatic artery was studied in 27 liver transplant recipients with a four-row CT scanner using the following parameters: collimation, 1 mm; slice width, 1 mm; table feed, 6-8 mm/s; spiral reconstruction time, 0.5 s; reconstruction interval, 0.5 mm; mAs, 160; kVp, 120. Before the study, the patients received 1000 ml of water as oral contrast agent to produce negative contrast in the stomach and the small bowel. A non-ionic contrast medium was infused intravenously at a rate of 5 ml/s with a bolus tracking system. Volume-rendering of hepatic artery was performed with the 3D Virtuoso software. RESULTS: The celiac trunk, the hepatic artery, and the right and left hepatic arteries were successfully displayed in high detail in all patients. Side branches, including small collaterals, and hepatic artery anastomosis could also be readily visualized. Volume-rendered CTA detected six hepatic artery stenoses, two hepatic artery thromboses, and two intrahepatic pseudoaneurysms. In two cases, CT detected hepatic artery stenosis with a diameter reduction of less than 50%, while digital subtraction angiography showed a normal artery. CONCLUSION: Volume-rendered multi-detector CTA is a promising non-invasive technique, since it allows images of high quality to be generated with excellent anatomical visualization of the hepatic artery and its complications in liver transplant recipients.

Percutaneous image-guided radiofrequency ablation in the therapeutic management of hepatocellular carcinoma.

Owing to surveillance programs for detection of hepatocellular carcinoma (HCC) in patients with cirrhosis, more tumors are being detected at an early, asymptomatic stage. Percutaneous ablation is considered the best treatment option for patients with Child-Pugh class A or B cirrhosis and a single, nodular-type HCC smaller than 5 cm or as many as three HCC lesions, each smaller than 3 cm, when surgical resection or liver transplantation is not suitable. Radiofrequency ablation (RFA) has emerged as the most powerful method for percutaneous treatment of early-stage HCC. Recent studies have shown that RFA can achieve more effective local tumor control than ethanol injection and with fewer treatment sessions. In a randomized trial, local recurrence-free survival rates were significantly higher in patients who received RFA than in those treated by ethanol injection, and treatment allocation was confirmed as an independent prognostic factor by multivariate analysis. Due to advances in radiofrequency technology, RFA also has been used to treat patients with more advanced tumors. Preliminary reports have shown that RFA performed after balloon catheter occlusion of the hepatic artery, transarterial embolization, or chemoembolization results in increased volumes of coagulation necrosis, thus enabling successful destruction of large HCC lesions. This report reviews the current status of percutaneous, image-guided RFA in the therapeutic management of HCC.

Multidetector CT of the small bowel: evaluation after oral hyperhydration with isotonic solution.

PURPOSE: The aim of our study was to assess the diagnostic capabilities of multidetector CT in the evaluation of the small bowel in different pathological conditions, with the use of oral hyperhydration with isotonic solution. MATERIALS AND METHODS: The study retrospectively evaluated 106 patients who underwent multidetector CT of the small bowel. Four groups were considered on the basis of the clinical findings: group A (48 cases), with suspected or certain chronic inflammatory disease of the small bowel; group B (16 cases), with suspected neoplastic lesion of the small bowel; group C (17 cases), patients affected by malabsorption; group D (25 cases), others: 13 cases with non-specific abdominal pain, 4 cases with occult bleeding, 8 cases affected by fever of unknown origin. Thirteen patients had previously undergone surgical intestinal resection. In all cases the CT examination was performed after the oral administration of 2000 mL polyethylene glycol electrolyte balanced solution; before the scan, N-butyl scopolamine or glucagon were administered intravenously to obtain rapid inhibition of bowel peristalsis. All multidetector CT scans were acquired at baseline and 50 seconds after the I.V. administration of 110-130 ml high-concentration non-ionic iodinated contrast medium. The images were subsequently processed on a dedicated workstation (Advantage Windows 4.0, GE Medical Systems) to obtain multiplanar reconstruction (MPR). We considered the following CT findings: fold distribution, wall thickening and stratification and contrast enhancement, extraparietal involvement and abnormalities of the abdominal organs. The CT diagnoses were compared with the clinical and laboratory findings (86 cases) and with the results of barium follow-through (55 cases), ileo-colonoscopy (45 cases) or surgery (28 cases). RESULTS: CT examination allowed the correct diagnosis in 86/106 cases (89%); 20 patients were not included in the study because of a poor (11 cases) or absent (9 cases) small bowel loop distension. The final diagnoses in the 86 patients were: Crohn's disease of the small bowel (38 cases), Crohn's disease of the duodenum (1 case), granulomatous colitis (3 cases), malabsorption (8 cases), neoplastic lesion (4 cases), post-radiation conglomeration of ileal loops (1 case), intestinal lymphangiectasia (1 case), ulceration of the last ileal loop (1 case). In 29 cases no abnormalities of the small bowel were found. Spiral CT yielded 52 true positive cases, 5 false negative cases, 2 false positive cases, and 27 true negative RESULTS: The sensitivity of the technique was 91%, specificity 93% and diagnostic accuracy 92%. CONCLUSIONS: Multidetector CT of the small bowel performed after oral hyperhydration with isosmotic solution, proved to be an accurate and thorough technique. It can be considered a safe and effective alternative to conventional radiographic studies and to small bowel spiral CT enema in patients that refuse the nasojejunal balloon catheter or the administration of methylcellulose.