Predicting early recurrence after resection of initially unresectable colorectal liver metastases: the role of baseline and pre-surgery clinical, radiological and molecular factors in a real-life multicentre experience

BACKGROUND

Advances in surgical techniques and systemic treatments have increased the likelihood of achieving radical surgery and long-term survival in metastatic colorectal cancer (mCRC) patients with initially unresectable colorectal liver metastases (CRLMs). Nonetheless, roughly half of the patients resected after an upfront systemic therapy experience disease relapse within 6 months from surgery, thus leading to the question whether surgery is actually beneficial for these patients.

MATERIALS AND METHODS

A real-world dataset of mCRC patients with initially unresectable liver-limited disease treated with conversion chemotherapy followed by radical resection of CRLMs at three high-volume Italian institutions was retrospectively assessed with the aim of investigating the association of baseline and pre-surgical clinical, radiological and molecular factors with the risk of relapse within 6 or 12 months from surgery.

RESULTS

Overall, 268 patients were included in the analysis and 207 (77%) experienced recurrence. Ninety-six (46%) of them had disease relapse within 6 months after CRLM resection and in spite of several variables associated with early recurrence at univariate analyses, only primary tumour resection at diagnosis [odds ratio (OR) 0.53, 95% confidence interval (CI) 0.32-0.89, P = 0.02] remained significant in the multivariable model. Among patients with resected primary tumours, pN+ stage was associated with higher risk of disease relapse within 6 months (OR 3.02, 95% CI 1.23-7.41, P = 0.02). One hundred and forty-nine patients (72%) had disease relapse within 12 months after CRLMs resection but none of the analysed variables was independently associated with outcome.

CONCLUSIONS

Clinical, radiological and molecular factors assessed before and after conversion chemotherapy do not reliably predict early recurrence after secondary resection of initially unresectable CRLMs. While novel markers are needed to optimize the cost/efficacy balance of surgical procedures, CRLM resection should be offered as soon as metastases become resectable during first-line chemotherapy to all patients eligible for surgery.

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.

Italian consensus guidelines for chronic pancreatitis

This paper gives practical guidelines for diagnosis and treatment of chronic pancreatitis. Statements have been elaborated by working teams of experts, by searching for and analysing the literature, and submitted to a consensus process by using a Delphi modified procedure. The statements report recommendations on clinical and nutritional approach, assessment of pancreatic function, treatment of exocrine pancreatic failure and of secondary diabetes, treatment of pain and prevention of painful relapses. Moreover, the role of endoscopy in approaching pancreatic pain, pancreatic stones, duct narrowing and dilation, and complications was considered. Recommendations for most appropriate use of various imaging techniques and of ultrasound endoscopy are reported. Finally, a group of recommendations are addressed to the surgical treatment, with definition of right indications, timing, most appropriate procedures and techniques in different clinical conditions and targets, and clinical and functional outcomes following surgery.

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.

Solitary hilar biliary adenoma: MR imaging and MR cholangiography features with pathologic correlation

Biliary adenoma is a rare tumour characterized by the proliferation of bile duct epithelium into the lumen. Diagnosis is usually based on the imaging findings of bile duct dilatation and intraductal mass. We describe previously un-reported magnetic resonance imaging and magnetic resonance cholangiography features with endoscopic retrograde cholangiography and pathologic correlation of a solitary hilar biliary adenoma.

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.

Ischemic-type biliary lesions in liver transplant recipients: evaluation with magnetic resonance cholangiography

We assessed the diagnostic value of magnetic resonance cholangiography (MRC) when evaluating ischemic-type biliary lesions in the follow-up of liver transplant patients. We retrospectively reviewed magnetic resonance imaging and MRC of 28 liver transplant recipients with ischemic changes of the biliary tree. The MR examinations were performed at 1.5 T. After the acquisition of axial T1w and T2w sequences, MRC involved a coronal respiratory-triggered, fat-suppressed, two-dimensional, thin-slab, heavily T2w fast spin-echo sequence, and/or a coronal breath-hold, thin- and thick-slab, single-shot T2w sequence. Eleven patients underwent either surgical reconstruction of the biliary system (n = 4) or liver retransplantation (n = 7); the pathologic specimens were employed as standard of reference. The final diagnosis was obtained through direct cholangiography in the remaining cases. Without knowledge of the surgical, pathologic, and cholangiographic findings, two experienced investigators evaluated in conference the MR images to determine the presence of biliary tract abnormalities. MRC demonstrated strictures involving the hepatic bifurcation and the extrahepatic bile duct of the graft in 26 patients; a concomitant thickening of the biliary wall was described in 18 out of these 26 subjects. MRC also showed sludge or stones formation in the donor common bile duct in 16 out of these patients. In conclusion, MRC allows noninvasive, reliable, assessment of ischemic-type biliary lesions in liver transplant recipients.

Complications of orthotopic liver transplantation: imaging findings

Orthotopic liver transplantation has become the major treatment for end-stage chronic liver disease and for severe acute liver failure. Despite the improvement in survival due to advances in organ preservation, improved immunosuppressive therapy agents, and refinement of surgical techniques, there are significant complications after liver transplantation. These complications mainly include biliary strictures, stones, and leakage; arterial and venous stenoses and thromboses; lymphoproliferative disorders; recurrent tumors; hepatitis virus C infection; liver abscesses; right adrenal gland hemorrhage; fluid collections; and hematomas. The diagnosis of acute rejection, one of the most serious complications after liver transplantation, is established with graft biopsy and histologic study. The role of imaging methods consists of excluding the other complications, which can have clinical signs and symptoms similar to those of acute rejection. This pictorial essay describes imaging findings of the various complications after liver transplantation and focuses on their radiologic diagnosis. Knowledge and early recognition of these complications with the most suitable imaging modality are crucial for graft and patient survival.

Surgical complications after liver transplantation

AIM

The number of liver transplantations in Italy has steadily increased over the last 10 years as a result of the use of donors aged more than 60 years. The use of organs with a reduced functional reserve has been compensated for by improvements in immunosuppressive therapy, surgical techniques and the management of postoperative complications. This article describes the incidence and treatment of the main surgical complications after liver transplantation.

METHODS

Between January 1996 and June 2003, 398 patients received 430 transplants at our Centre. Thirty-seven early relaparotomies were performed (8.6%), including 12 retransplantation (2.8%). The 1-, 3- and 5-year actuarial survival of the patients was 79.8%, 72.2% and 67.5%, and that of the grafts was 75.9%, 68% and 63.4%. Perioperative mortality was 10.5% (with no intraoperative deaths).

RESULTS

The overall incidence of biliary complications was 31.6%, 9.1% of which were due to the removal of the Kehr tube. There were 42 (9.8%) anastomotic stenoses, 5 (1.2%) extra-anastomotic stenoses, 1 (0.2%) anastomotic leak, 5 (1.2%) extra-anastomotic leaks, and 19 (4.4%) ischemic-type biliary lesions. The overall incidence of vascular complications was 6.9%: 7 (1.6%) cases of hepatic artery thrombosis, 17 (4.0%) arterial stenoses, 1 (0.2%) arterial pseudoaneurysm, 4 (0.9%) cases of portal thromboses and 1 (0.2%) case of caval laminar thrombosis. Eight patients (1.9%) developed massive and persistent post-transplant ascites and/or hydrothorax.

CONCLUSION

The use of donors aged more than 60 years makes it possible to maintain high standards of patient and graft survival that is not only due to the optimisation of immunosuppressive protocols, but also to improvements in surgical techniques, intensive care and the management of surgical complications.

Detection of common bile duct stones before laparoscopic cholecystectomy. Evaluation with MR cholangiography

PURPOSE

To assess the diagnostic value of MR cholangiography (MRC) for detecting common bile duct (CBD) stones in candidates for laparoscopic cholecystectomy (LC).

MATERIAL AND METHODS

A series of 95 selected patients with gallstones and suspected CBD lithiasis (abnormal serum liver tests and/or CBD size > or = 6.5 mm at US) were referred to our institution for MRC, before LC. MRC was performed on a 0.5 T magnet through a non-breath-hold, respiratory-triggered, fat-suppressed, thin-slab, heavily T2-weighted fast spin-echo sequence and through a breath-hold, thick-slab, single-shot T2-weighted sequence in the coronal plane. Axial T1- and T2-weighted sequences were first obtained. Two observers in conference reviewed source images and maximum intensity projections to determine the presence or absence of choledocholithiasis. MR findings were compared with endoscopic retrograde cholangiography and intraoperative cholangiography (IOC); IOC was always performed during LC.

RESULTS

CBD calculi (single or multiple) were identified in 41 out of 95 patients (43%). Two false-positive and 4 false-negative cases were found on MRC. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of MRC for choledocholithiasis were 90%, 96%, 94%, 95%, and 93%, respectively.

CONCLUSION

MRC is a highly effective diagnostic modality for evaluation of patients with risk factors for CBD stones prior to LC.

Detection of common bile duct stones before laparoscopic cholecystectomy. Evaluation with MR cholangiography

PURPOSE

To assess the diagnostic value of MR cholangiography (MRC) for detecting common bile duct (CBD) stones in candidates for laparoscopic cholecystectomy (LC).

MATERIAL AND METHODS

A series of 95 selected patients with gallstones and suspected CBD lithiasis (abnormal serum liver tests and/or CBD size > or = 6.5 mm at US) were referred to our institution for MRC, before LC. MRC was performed on a 0.5 T magnet through a non-breath-hold, respiratory-triggered, fat-suppressed, thin-slab, heavily T2-weighted fast spin-echo sequence and through a breath-hold, thick-slab, single-shot T2-weighted sequence in the coronal plane. Axial T1- and T2-weighted sequences were first obtained. Two observers in conference reviewed source images and maximum intensity projections to determine the presence or absence of choledocholithiasis. MR findings were compared with endoscopic retrograde cholangiography and intraoperative cholangiography (IOC); IOC was always performed during LC.

RESULTS

CBD calculi (single or multiple) were identified in 41 out of 95 patients (43%). Two false-positive and 4 false-negative cases were found on MRC. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of MRC for choledocholithiasis were 90%, 96%, 94%, 95%, and 93%, respectively.

CONCLUSION

MRC is a highly effective diagnostic modality for evaluation of patients with risk factors for CBD stones prior to LC.

Detection of biliary complications after orthotopic liver transplantation with MR cholangiography

To assess the diagnostic value of magnetic resonance cholangiography (MRC) when evaluating biliary complications in the follow-up of liver transplant patients. One hundred and thirteen patients prospectively underwent MR imaging and MR cholangiography at 1.5-T unit after orthotopic liver transplantation (OLT). After the acquisition of axial T1- and T2-weighted sequences, MRC involved a coronal, non breath-hold, respiratory-triggered, fat-suppressed, two-dimensional, thin-slab, heavily T2-weighted fast spin-echo sequence, and coronal breath-hold, thick-slab, single-shot T2-weighted sequences. The images and maximum intensity projections were evaluated by two readers in order to determine biliary anatomy and the presence of complications, whose final diagnosis was based on endoscopic retrograde cholangiography (ERC) in 50 patients, percutaneous trans-hepatic cholangiography (PTC) in five, and by integrating clinical follow-up with ultrasound and MR findings in 58 cases. MRC had a sensitivity of 93%, a specificity of 92%, a positive predictive value of 86%, a negative predictive value of 96%, and a global diagnostic accuracy of 93% in detecting all types of biliary complications in OLT patients. MRC is a reliable technique for detecting post-OLT biliary complications. We now restrict the use of ERC to patients for whom therapeutic procedures are advocated or whose MRC results are equivocal.

MR virtual endoscopy of the upper urinary tract

OBJECTIVE

We investigated the feasibility of applying surface-rendered virtual endoscopy to the visualization of the upper urinary tract by processing unenhanced MR urography data sets.

SUBJECTS AND METHODS

Twenty-six patients, having neoplastic lesions (n = 9), calculi (n = 8), pelviureteric junction stenoses (n = 4), postoperative fibrotic strictures (n = 3), and extrinsic compressions of the ureter (n = 2), underwent unenhanced MR urography. Virtual endoscopy of the upper urinary tract was obtained using a thresholding technique and surface-rendering MR urography data sets.

RESULTS

Virtual endoscopy of the renal pelvis and calices was feasible in all cases on the side of the urinary obstruction. Virtual endoscopy of the ureter was obtained for a diameter of at least larger than 5 mm. The nondilated side could be partially explored in 11 cases (43%). The mean virtual endoscopy threshold required for the visualization of the urinary tract was 157.36-159.94. The mean time for virtual endoscopy was 13.8 min. Endoluminal masses were found in three (12%) of 26 cases on the renal pelvis (corresponding to neoplastic lesions), and occlusions, in 23 (88%) of 26 on the pelviureteric junction and ureter (neoplastic lesions and other abnormalities).

CONCLUSION

Virtual endoscopy of MR urography data sets is feasible in patients with urinary tract dilatation. Virtual endoscopy displays the renal pelvis, calices, and ureter and, moreover, can show endoluminal changes caused by abnormalities.

Real-time volume rendering of MRCP: clinical applications

MR-cholangiopancreatography (Signa Contour 0.5T; GE/Medical Systems, Milwaukee, WI) data sets of 156 patients, obtained with a 2D T2-weighted FSE sequence, in the coronal plane, were volume rendered (Advantage Windows 3.1; GEMS) independently by two radiologists, that were asked to define the range of signal intensities in which the signal of the pancreaticobiliary system was included and to rank the quality of native images and volume renderings. Patients had biliary stones (n = 47), inflammatory ampullary stenoses (n = 18), pancreatic tumors (n = 12), surgical bilio-enteric anastomoses (n = 19), ampullary carcinomas (n = 2), pancreatic duct stone (n = 1), cholangiocarcinoma (n = 3) and normal pancreaticobiliary tree (n = 54). Good quality volume renderings of the bile ducts were obtained for at least a maximum diameter of 1.5 mm. The quality rank agreement between volume rendering and native images was excellent (k = 0.94). The correlation between the observers for the setting the signal intensity range was excellent and statistically significant (P < 0.001). The correlation between the observers for the time of volume rendering was not statistically significant. Biliary stones could be displayed in 32/47 (68%) cases. The pancreatic duct stones was displayed as well. Inflammatory ampullary stenoses were detected in all cases (100%). In case of pancreatic tumors, cholangiocarcinomas and ampullary carcinomas volume rendering allowed to identify the site of stenosis. In surgical bilio-enteric anastomoses volume rendering was helpful to display the residual biliary tract, the site of anastomosis and the enteric tract. Volume rendering could be a reliable and efficient tool for the study of the anatomy and pathological changes of the pancreaticobiliary tract.

MR cholangiopancreatography: value of axial and coronal fast Spin-Echo fat-suppressed T2-weighted sequences

OBJECTIVE

To compare axial and coronal fast Spin-Echo fat-suppressed T2-weighted sequences with three-dimensional (3D) maximum intensity projection (MIP) images in patients with suspected pancreaticobiliary obstruction.

MATERIAL AND METHODS

MR cholangiopancreatography (MRCP) was performed in 108 consecutive patients with a non-breath-hold, fat-suppressed, 2D, heavily T2-weighted fast spin-echo sequence in coronal plane. Axial T1- and T2-weighted images were previously obtained. In addition, 3D reconstructions of the coronal images were analysed separately by using a MIP algorithm. Both two-dimensional (2D) (axial and coronal) and 3D MIP images were separately evaluated by two readers in conference and their results were compared with that of endoscopic retrograde cholangiopancreatography, percutaneous trans-hepatic cholangiography, surgery and/or imaging follow-up. Statistical analysis of 2D and 3D MRCP images in diagnosing the level and probable cause of pancreaticobiliary obstruction were separately calculated.

RESULTS

106/108 of MRCP examinations were judged diagnostic by the two reviewers for adequacy of visualisation of the biliary and pancreatic ducts. Sensitivity, specificity, positive predictive value, negative predictive value and global diagnostic accuracy of 2D (axial and coronal) and 3D MRCP images in diagnosing the pancreaticobiliary obstruction were 94 and 57%,, 95 and 93%, 97 and 92%, 91 and 60%, 94 and 72% respectively.

CONCLUSION

Our results do indicate a higher global accuracy for axial and coronal fast Spin-Echo fat-suppressed T2-weighted sequences versus 3D MIP images in diagnosis of the level and probable cause of pancreaticobiliary obstruction and stress the limitations of 3D images in depiction of small intraductal pathology such as calculi and biliary neoplastic.

Choledocolithiasis: diagnostic accuracy of MR cholangiopancreatography. Three-year experience

The purpose of this study was to evaluate the diagnostic accuracy of MR cholangiopancreatography (MRCP) in the detection of common bile duct stones. A series of 286 consecutive patients were referred for MRCP, that was performed with a 1.5 T MR unit, through a non-breath-hold, respiratory-triggered, fat-suppressed, two-dimensional, heavily T2-weighted fast spin-echo sequence in the coronal plane. Axial T1 and T2-weighted sequences were first obtained. Axial, coronal, and Maximum Intensity Projection images were evaluated by three independent readers, who were asked to determine whether stones were present or not inside the biliary tract. The findings of MRCP images were compared with endoscopic retrograde cholangiopancreatography, percutaneous trans-hepatic cholangiography, intra-operative cholangiography, surgical, or imaging follow-up findings. Two-hundred and seventy-eight out of 286 MRCP examinations were judged diagnostic by the three reviewers. Among the 278 patients included in our study group, biliary tract lithiasis was proved in 76 cases (27%). On the basis of reviewers' reading, MRCP had sensitivity 92-93%, specificity 97-98%, positive predictive value 91-93%, negative predictive value 97-98%, and the diagnostic accuracy ranged between 95% and 96% in the detection of calculi. Interobserver agreement was excellent (K = 0.84, kappa statistic). MRCP showed a high diagnostic accuracy and an excellent inter-observer agreement in the detection of common bile duct stones.

MR virtual endoscopy of the pancreaticobiliary tract: a feasible technique?

To evaluate the feasibility of magnetic resonance (MR) virtual endoscopy of the pancreaticobiliary tract by using MR cholangiopancreatography (MRCP) data sets as source images, we retrospectively reviewed MRCP data sets of 120 patients with Navigator software (GE/Medical Systems, Milwaukee, WI) that allowed display of inner views by surface rendering the internal wall of the bile ducts with simulated light and shadow.

Diagnosis of adrenal adenoma: value of central spot of high-intensity hyperintense rim sign and homogeneous isointensity to liver on gadolinium-enhanced fat-suppressed spin-echo MR images

Eighty-nine patients with 108 adrenal masses, either adenomas (n = 88) or malignant lesions (n = 20), underwent magnetic resonance imaging (MRI) of the abdomen at 0.5 T for the purpose of determining whether adrenal adenomas could be differentiated from malignant lesions on gadolinium-enhanced fat-suppressed T1-weighted spin-echo (SE) images (Gd-E FS T1WI) and on T2-weighted SE images. The imaging protocol included conventional unenhanced SE T1- and T2-weighted sequences and Gd-E FS T1WI. Three observers independently evaluated signal intensity on unenhanced and enhanced images and also the presence of structures of high signal intensity in the outer margin [hyperintense rim sign (HRS)] or in the center [hyperintense central spot (HCS)] of the adrenal masses. Forty-one (46.5%) of 88 adenomas were homogeneously isointense to liver in unenhanced and enhanced T1-weighted sequences and in T2WI. HCS and HRS were observed in 33/88 (37.5%) and 15/88 (17%) adenomas, respectively, on Gd-E FS T1WI; in contrast, these signs were never revealed in any case of malignant lesions. Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy in classifying lesions as suggestive of adenoma were 93%, 90%, 98%, 75%, and 93%, respectively. Visual evaluation of details of tumor structures on Gd-E FS T1WI allows good characterization of adrenal masses. HCS, HRS, and homogeneous isointensity to liver are characteristic signs of adrenal adenomas.

Magnetic resonance appearance of asbestos-related benign and malignant pleural diseases

OBJECTIVES

This study describes the magnetic resonance findings of benign and malignant pleural diseases in asbestos-exposed subjects.

METHODS

Thirty patients with a history of asbestos exposure and pleural lesions in chest X-rays and computed tomography scans were examined with a 0.5- and a 1.5-T magnetic resonance unit. The examination protocol included cardiac-gated proton density and T2-weighted images, unenhanced and enhanced (Gd-DTPA; 0.1 mmol/ kg) T1-weighted images in the axial plane and sometimes in another orthogonal plane (sagittal or coronal or both). All the magnetic resonance images were reviewed by 3 experienced observers, who visually evaluated morphologic features, signal intensity, and contrast enhancement of pleural lesions. The diagnosis was established by means of percutaneous biopsy, thoracotomy, and combined clinical and radiological follow-up for at least 3 years.

RESULTS

Eighteen patients affected with multiple pleural plaques showed low signal intensity on both unenhanced and enhanced T1-weighted and proton density and T2-weighted images. In 2 of these patients an acute pleural effusion was observed. All the malignant lesions (11 mesotheliomas) and a solitary benign pleural plaque revealed high signal intensity on the proton density and T2-weighted images and inhomogeneous contrast enhancement in the postcontrast T1-weighted images. The sensitivity, specificity, and diagnostic accuracy of the magnetic resonance imaging in classifying a lesion as suggestive of malignancy were 100%, 95% and 97%, respectively.

CONCLUSIONS

The results point out 2 magnetic resonance signal intensity patterns for asbestos-related pleural lesions: (i) low-signal intensity on unenhanced and enhanced T1-weighted and proton density and T2-weighted images for benign plaques and (ii) nonhomogeneous hyperintensity in T2-weighted and enhanced T1-weighted images for malignant mesotheliomas.

MR virtual endoscopy of the pancreaticobiliary tract

PURPOSE

To evaluate the feasibility of surface-rendered magnetic resonance virtual endoscopy (MRVE) of magnetic resonance cholangiopancreatography (MRCP) data sets. We retrospectively reviewed MR cholangiopancreatography data sets of 120 patients with biliary stone (n=40), inflammatory ampullary stenosis (n=12), pancreatic tumor (n=8), cholangiocarcinoma (n=7), stenosis of surgical bilio-enteric anastomosis (n=4), extrinsic localized common bile duct stenosis (n=2), ampullary carcinoma (n=2), pancreatic duct stone (n=1), tumor of the gallbladder (n=1), and normal pancreaticobiliary tree (n=43). MRVE views were generated with Navigator software. Segmentation of the acquired data sets was performed with a thresholding technique. Navigation sequences were simulated through the entire biliary tract. MRVE was obtained in 27 (63%) of the 43 normal patients. Endoscopic views were generated in all 77 patients with partial or complete obstruction of the pancreaticobiliary tree. Among these, three groups of patterns were identified: 36 (47%) endoluminal masses (polyp-like masses), 17 (22%) luminal stenoses, 24 (31%) luminal occlusion. In 29 cases, hole artifacts through the internal wall were observed and interpreted as mistakes of segmentation. MRVE proved to show the internal anatomy of the biliary tract and endoluminal changes due to pathological condition. Further investigations are needed to test the usefulness and the potentialities of this technique.

Incidentally discovered adrenal masses: evaluation with gadolinium enhancement and fat-suppressed MR imaging at 0.5 T

The purpose of the study is to evaluate the ability of Gd-enhancement and fat-suppressed MR imaging operating at midfield strength to characterize incidentally discovered adrenal masses. Sixty patients with 72 adrenal masses incidentally discovered during US or CT exams were studied with a 0.51 MR unit following clinical and laboratory evaluation. After Gd-DTPA intravenous administration a modified three-point Dixon technique was performed in all patients. This technique provided three images sets: conventional T1-weighted SE images, fat-suppressed T1-weighted images and water-suppressed T1-weighted images. Diagnosis was established by means of surgery (11 lesions), fine-needle biopsy (21 lesions) and stability on ultrasonographic follow-up for at least 1 year (range, 12-87 months) from adrenal lesion discovery (40 masses). In most of adenomas (n = 55) an homogeneous enhancement was observed on postcontrast T1WI; however, 15 out of these lesions showed a small focal spot of high intensity in Gd-enhanced fat-suppressed images. On the contrary, malignant conditions (n = 6) and pheochromocytoma (n = 1), all had inhomogeneous signal intensities which were relatively higher after Gadolinium injection as compared with the liver. The fat suppression technique demonstrated areas of bright signal intensity related to high vascularity. The performance of three observers in order to differentiate malignant from benign conditions showed sensitivity, specificity, diagnostic accuracy, positive and negative predictive values of 100, 88.5, 90, 50 and 100% on the basis of gadolinium enhancement only, by utilizing the Dixon technique. In conclusion, although Gd-enhancement and fat-suppressed sequence helped correctly differentiate among the groups of incidentally discovered adrenal masses, the degree of overlap suggests that it is still difficult to characterize individual patients. However, the modified three-point Dixon technique after contrast material administration appears to be a further capability of midfield MRI in the characterization of adrenal tissue.

[Usefulness of the modified Dixon technique associated with gadolinium administration in the characterization of adrenal masses]

We investigated the usefulness of modified Dixon technique at 0.5 T after Gadolinium (Gd) administration in the characterization of adrenal masses. One hundred and one patients (45 men, 56 women; mean age: 60.5 +/- 13.5 years) with 125 adrenal masses found at previous US or CT of the abdomen were submitted to MRI. The study protocol included preliminary T1-weighted, PD and T2-weighted SE images. A bolus of 0.1 mmol/kg Gd-DTPA was administered and then T1-weighted SE scans were acquired with modified Dixon technique (TR = 450-600 ms, TE = 30 ms, 192 x 192 matrix, no craniocaudal presaturation). Acquisition time is twice as long with this technique as with conventional SE sequences, but three sets of T1-weighted images are acquired: conventional SE, fat-suppressed and water-suppressed images. The diagnosis was made at surgery (18 lesions) and fine-needle biopsy (34 lesions), or with stable US follow-up findings for at least 1 year (73 masses). Adrenocortical adenomas (no. 88) were homogeneously isointense to liver in pre- and postcontrast images, but 32 of them exhibited a small high intensity spot in enhanced fat-suppressed images. Malignant lesions and pheochromocytomas (no. 19) had inhomogeneous signal intensity, with relatively higher signal on T2-weighted and Gd-enhanced fat-saturated images. Fat-water images were useful to assess fatty and myeloid components within myelolipomas (no. 7). Benign conditions were distinguished from malignant conditions with 90% sensitivity, 93% specificity and 92.5% diagnostic accuracy. To conclude, modified three-point Dixon technique after contrast agent administration appears to be another useful diagnostic application of midfield MRI to characterize adrenal tissues.

[Usefulness of pirenzepine in the study of the upper digestive tract and the large intestine with double contrast media: comparison with scopolamine methylbromide]

The purpose of the present study is to assess the importance of pirenzepine, a selective M1 antimuscarinic drug, as hypotonic agent for diagnostic double-contrast studies of the upper gastrointestinal tract and for double-contrast barium enema studies of the large bowel. Pirenzepine and scopolamine methylbromide (SMB) (Buscopan) were compared in a single blind randomized trial. One hundred-thirty consecutive patients were enrolled in the study. Seventy of them underwent double-contrast studies of the stomach and duodenum and sixty double-contrast barium enema studies of the large bowel. Visceral distension and painting of stomach, duodenal bulb and large bowel and global quality of the images were blindly evaluated by 4 independent observers by means of a numerical score (1 to 4). Quantitative analysis of bowel distension was done measuring the maximum diameter of the transverse colon before and after drug administration. No differences were found in the diagnostic performance between the two drugs in the study of the duodenal bulb (2.8 +/- 0.8 vs 2.9 +/- 0.7, p = NS) and of the large bowel (3.0 +/- 0.6 vs 3.1 +/- 0.6, p = NS). Under SMB, slightly but significantly better results were obtained in the stomach (3.0 +/- 0.6 vs 2.7 +/- 0.6, p = 0.01). However, large bowel distension was slightly but significantly improved with Pirenzepine (68 +/- 12 vs 65 +/- 8 mm, p = 0.02). Heart rate and rhythm during the study were recorded by ECG. SMB induced tachycardia in all patients while pirenzepine did not. Moreover, after SMB, 3 patients exhibited faintness, some patients complained of visual accommodation defects, dryness of the mouth and dizziness. Under pirenzepine, no side-effects were reported. To conclude, pirenzepine gives good results in double contrast studies, as good as SMB but with no adverse effects; thus, it could be proposed as the hypotonic agent of choice in upper gastrointestinal and large bowel examinations.

Pulmonary function, smoking habits, and high resolution computed tomography (HRCT) early abnormalities of lung and pleural fibrosis in shipyard workers exposed to asbestos

To evaluate the presence of asbestos-related pleural and parenchymal abnormalities and their correlation with pulmonary function and smoking habits, 119 asbestos-exposed asymptomatic workers (mean age, 46.2 years; mean duration of asbestos exposure, 8.6 years; mean latency time, 21.6 years) with normal standard P.A chest radiographs were submitted to HRCT, CO-diffusing capacity and pulmonary function tests. HRCT scans were normal only in 31 (26%) examined workers; 31 (26%) subjects showed both pleural and parenchymal involvement, and 50 (42%) and seven (6%) had exclusively pleural and parenchymal abnormalities, respectively. Based on CO-diffusing capacity and pulmonary function tests, no significant difference was demonstrated between workers with pleural lesions and subjects with normal pleura; however, lower values of FVC were observed in the nonsmoking workers with parenchymal abnormalities in comparison with nonsmoking subjects with normal parenchyma (78.2 vs. 89.7% of predicted values; p = 0.03 by student's two-tailed t test), and lower values of FEV1/FVC in the smokers with parenchymal lesions with respect to smokers with normal parenchyma (93.7 vs. 100.2% of predicted values; p = 0.005 by students' two-tailed t test). In conclusion, our results demonstrate that HRCT may detect early parenchymal abnormalities which correlate with exposure to asbestos and respiratory function impairment, including a reduction in obstructive indices in smokers occupationally exposed to asbestos, without any clinically evident disease.

[Adrenal myelolipomas: their magnetic resonance assessment]

Adrenal myelolipomas are rare nonfunctioning neoplasias consisting of a variable mixture of mature fat and bone marrow tissue. In the present study MRI appearances of six adrenal myelolipomas are presented. MR exams of six patients in which a conclusive diagnosis of adrenal myelolipomas was reached by means of surgery (1 case), US-guided fine-needle biopsy (3 cases) and typical diagnostic imaging in association with stability on US follow-up for at least two years (2 cases) were retrospectively evaluated. MR sequences protocol included pre- and post-contrast (Gd-DTPA) SE T1-weighted images and SE proton density and T2-weighted images. Five adrenal masses were examined by means of combination of gadolinium administration with a SE T1-weighted modified three-point Dixon technique. Three different MR structural patterns were pointed out: a) homogeneous hyperintense masses on T1-weighted images with intermediate signal on T2-weighted images, suggestive for predominantly fat-containing lesions (2 cases); b) heterogeneous masses with fat intensity areas and hyperintense areas on T2-weighted images and on post-contrast T1-weighted images, suitable for mixed fatty and myeloid elements (2 cases); c) nodules hypointense to the liver on T1-weighted images and hyperintense on T2-weighted images and after gadolinium administration, suggesting tumors primarily composed of myeloid cells (2 cases). A precise determination of fatty and myeloid elements within the lesions was observed by means of "water" and "fat" images provided by modified three-point Dixon technique. In conclusion, MRI allows to determine the various structural components of myelolipomas and therefore appears to be a very reliable technique in the diagnosis and characterization of the different structural patterns of this rare adrenal pathology.

[Inflammatory aneurysm of the abdominal aorta: TC assessment of the postoperative course]

This study was aimed at investigating CT reliability in the postoperative follow-up of inflammatory abdominal aortic aneurysms (IAAA) previously treated with prosthesis positioning. During the last 5 years, 13 male patients operated on for subrenal IAAA with intraluminal prosthesis positioning, were followed-up with CT. All CT images were reviewed by three radiologists to assess prosthesis integrity; the possible presence of intraluminal thrombosis was investigated, together with pre/postprosthetic dilatation and the involvement of inferior vena cava, ureters and third duodenal segment. The prostheses were intact and no signs of intraluminal thrombosis were depicted in all patients; a periprosthetic dilation of abdominal aorta associated with parietal thrombosis was observed in one patient. Nine patients exhibited mild-moderate thickening of the original aortic or iliac walls; the inferior vena cava was involved in 6 of them and the left ureter in one. Contact with the III duodenal segment was found in 3 patients. In conclusion, CT proves to be a reliable technique in the postoperative follow-up of IAAA, yielding accurate information about the prosthesis, the aortoiliac walls and retroperitoneal structures. Moreover, in our experience late postoperative complications were not of major clinical importance.

Ultrasound versus plain film in the detection of pneumoperitoneum

To evaluate ultrasound (US) versus conventional plain film radiography (CPF) in the detection of pneumoperitoneum, 30 patients with postsurgical pneumoperitoneum and a control group of 22 patients were studied using US and CPF. Sonograms and radiograms were obtained while patients were supine and in left lateral decubitus. The two orthogonal plain films of the abdomen were acquired with a horizontal X-ray beam. The epigastric region and right hypochondrium were investigated with ultrasonography. Four experienced, blinded radiologists examined 160 sonograms and 104 radiograms. Statistical analysis yielded a sensitivity of 75.7% for radiography versus 86% for ultrasonography, a specificity of 89.2% versus 83.5%, an accuracy of 81.5% versus 85%, a positive predictive value of 90.2% versus 87%, and a negative predictive value of 76.2% versus 83.5%, respectively. US could therefore be considered a reliable alternative imaging technique in the detection of pneumoperitoneum.

Pirenzepine versus scopolamine methyl bromide in double-contrast barium enema study of large bowel

To evaluate the usefulness of pirenzepine for diagnostic double-contrast barium enema study of the large bowel, pirenzepine and scopolamine methyl bromide (SMB) were compared in a single, blind, randomized trial. Sixty consecutive patients were enrolled in the study. Quantitative analysis of bowel distention was done by measuring the maximum diameter of the transverse colon before and after drug administration. Four independent observers blindly evaluated distention and mucosal coating of the large bowel and global quality of the images. No differences were found in the diagnostic performance between the two drugs. However, pirenzepine induced a slight but significantly larger distention of the large bowel (68 +/- 12 vs. 65 +/- 8 mm, p = 0.02). Heart rate and rhythm during the study were recorded by ECG. SMB induced tachycardia in all patients (from 72 +/- 15 to 98 +/- 24 beats/min, p < 0.01), whereas pirenzepine did not (from 76 +/- 13 to 78 +/- 20, p = NS). After SMB, one-patient exhibited faintness, and some patients complained of visual accommodation defects, dryness of the mouth, and dizziness. Pirenzepine had a diagnostic performance similar to SMB in avoiding adverse effects elicited by SMB.

[Occult post-traumatic osteochondral changes in the knee. Assessment with magnetic resonance]

Occult posttraumatic osteochondral injuries of the knee are bone and/or cartilage abnormalities which cannot be detected on plain radiographs. This study was aimed at investigating MR capabilities in the detection and characterization of occult bone and/or cartilage injuries in symptomatic patients with previous musculoskeletal trauma of the knee. We retrospectively selected 60 patients (45 men and 15 women; mean age: 33.1 +/- 16.3 years; range: 12-70 years) from our patients submitted to MRI of the knee during a 3-year period. These patients had a history of previous acute musculoskeletal trauma, negative conventional radiographs and MR signal intensity changes of the osteochondral structures. MR protocol included: SE T1-, PD and T2-weighted images and GRE T2-weighted images; imaging planes were the sagittal, the axial and the coronal planes. Plain radiographs and MR images were interpreted by three experienced readers in musculoskeletal radiology. Our reviewers confirmed normal conventional radiographic findings in all the patients enrolled in the study. According to morpho-topographic and signal intensity patterns, we identified three types of occult posttraumatic injuries: bone contusions or bone bruises or occult subcortical fractures (n 30), osteochondral injuries (n 26) and chondral injuries (n 4). A bone contusion was defined as a typical subcortical area of signal loss, with various shapes, on T1-weighted images and increased signal intensity on T2-weighted images. The cortical bone and articular cartilage below were normal in all cases. On the contrary, osteochondral lesions presented an association of cartilage and bone injuries with the same M(R) signal abnormalities. Thinning and focal interruptions of the cortical bone were demonstrated in all cases. Chondral lesions were characterized by a sudden discontinuity and irregularity of cortical bone outline and by small high-intensity spots in cartilage thickness on T2-weighted images, in the absence of any subchondral bone abnormality. Finally, 42 of 60 patients (70%) had an anterior cruciate ligament tear and 28 (45%) had a medial meniscus tear. In conclusion, MRI appears a very useful tool in the detection and characterization of the different types of occult bone and/or cartilage injuries of the knee in the patients with previous acute trauma. Moreover, the correct and early diagnosis of an osteochondral lesion does affect prognosis.

[Asbestos-related lesions detected by high-resolution CT scanning in asymptomatic workers. Specificity, relation to the duration of exposure and cigarette smoking]

The possibility to detect initial "preclinical" pulmonary lesions related to asbestos is under debate. The aim of this study is to report our experience. We have submitted to HRCT 70 shipyard workers with chest X-ray judged "normal" by "outside" readers (mean age 44.5 +/- 6.1 ys) with a similar grade of (low-level) exposure to amosite (mean duration of "direct"/"heavy" exposure was 4.2 +/- 4.9 ys; "environmental"/"light" exposure was 8.4 +/- 5.9 ys). Among the 70 workers, in 34 pleural plaques were shown, in 6 subjects parenchymal abnormalities alone and in 13 parenchymal and pleural abnormalities were found; in the last 17 workers no pathological finding was shown. In six subjects the presence of a combination of parenchymal abnormalities permitted us to diagnose asbestosis. The difference in the duration of exposure to asbestos for the subjects with both pleural and parenchymal involvement compared to all other groups of workers was statistically significant; also the difference in duration of exposure between workers with or without parenchymal involvement resulted significant. In a control group (20 subjects without any known professional exposure to asbestos) HRCT permitted us to identify 5 cases with small pleural plaques while only one case presented parenchymal bands; lesion frequency was significantly lower in comparison with the exposed group. Calcified plaques have been proved to be more common in the workers with heavier exposure, and no one of the reference group had calcified plaques. The CT-determined emphysema score was found to optimally correlate with smoking habit (pack/years). In conclusion our study suggests that pulmonary or pleural involvement can be shown by HRCT before the onset of any clinical symptomatology with high sensitivity and specificity. Furthermore the results seem to indicate that the prevalence of HRCT-shown parenchymal lesions and the severity of lung involvement among asbestos-exposed workers are related to the duration of exposure, as in most of clinically evident asbestos-related lung disorders, in contrast with previous observations.

Usefulness and safety of pirenzepine in double-contrast study of upper gastrointestinal tract: comparison with scopolamine methylbromide

To evaluate usefulness of pirenzepine, a selective M1 antimuscarinic drug, for diagnostic double-contrast study of the upper gastrointestinal tract, pirenzepine and scopolamine methylbromide (SMB) were compared in a single blind randomized trial. Seventy consecutive patients were enrolled in the study. Artifacts, bowel distention, painting of stomach and duodenal bulb, and global quality of the images were blindly evaluated by four independent observers by means of a numerical score (1-4). Under SMB slightly but significantly better results for stomach were scored (3.1 +/- .7 vs. 2.7 +/- 7, p < 0.01). No differences were found in the study of the duodenal bulb. Heart rate and rhythm during the study were recorded by electrocardiogram (ECG). SMB induced tachycardia in all patients (from 77 +/- 20 to 117 +/- 28 beats/min, p < 0.01) while pirenzepine did not (from 77 +/- 16 to 81 +/- 23, p = NS). After SMB, two patients exhibited faintness, and some patients complained of visual accommodation defects, dryness of the mouth, and dizziness. Thus, pirenzepine provides good results in double-contrast studies (equal to SMB), while presenting no adverse effects. It could be proposed as a first choice hypotonic agent in upper gastrointestinal examination.

Findings from high resolution computed tomography of the lung and pleura of symptom free workers exposed to amosite who had normal chest radiographs and pulmonary function tests

The lungs of 50 symptom free workers exposed to amosite and with normal pulmonary function tests were examined by high resolution computed tomography (HRCT). Twenty five had normal standard chest radiographs whereas the other 25 had radiographs interpreted as near normal (International Labour Office profusion score < 0/1 or suspected pleural plaques). In 13 of the workers the results of HRCT were negative; in 22 pleural plaques were found, in five there was only parenchymal involvement, and 10 had both pleural and parenchymal changes. The mean duration of exposure to amosite was significantly longer for the subjects with parenchymal signs than for those with normal parenchyma and for the workers with pleural plaques than for those with normal pleura and lung parenchyma. The prevalence of identified pleural and parenchymal abnormalities in the 50 workers was also significantly higher than in a reference group without exposure to asbestos. It is concluded that HRCT may detect initial lung and pleural involvement in symptom free workers exposed to amosite and the mean duration of exposure is longer for subjects with parenchymal or pleural involvement.

[Computed tomography diagnosis of small intestine carcinoid]

This study was aimed at evaluating CT diagnostic capabilities in detecting carcinoid tumors of the small bowel and comparing CT results with conventional radiographic findings. The CT diagnosis of carcinoid tumor was made in 6 cases based on CT findings. All patients had undergone conventional radiographs (transit or double-contrast studies of the small intestine) and 2 patients had undergone double-contrast barium enema of the colon. 500 ml of oral contrast medium were administered 2 hours, 1 hour and 15 minutes before CT scans, respectively. A hypotonic agent was injected i.v. immediately before the examination. Primary lesion extent, mesenteric involvement, extramesenteric lymph nodes and hepatic metastases were the investigated CT patterns. The first two variables were also assessed on plain radiographs. In all patients the diagnosis of enteric carcinoid tumor was confirmed at surgery or liver biopsy. CT proved to be useful in demonstrating the primary tumor in 5 cases, mesenteric involvement in all patients, liver metastases in 3, lymphadenopathy in none. CT yielded very accurate findings and thus allowed the diagnosis of carcinoid tumor to be made in all the 6 patients, while plain films resulted normal in 2 cases and aspecific in 4. In conclusion, CT, if adequately performed, proved the best technique to detect carcinoid tumors of the small bowel. Of course, further evidence is required.

[Systematic evaluation of the pulmonary circulation with computerized tomography: normal and post-embolic pathologic features]

Pulmonary circulation was evaluated in normal subjects and in post-embolic patients. Eight normal subjects, 3 patients with acute pulmonary embolism and 8 patients with chronic thromboembolic pulmonary hypertension underwent CT of the chest. High-resolution CT and angio-CT were performed to study pulmonary parenchyma and pulmonary arteries, respectively. CT showed thrombi in the main or interlobar pulmonary arteries in all 3 cases of acute pulmonary embolism and in 4 of 8 patients affected with chronic thromboembolic pulmonary hypertension. The diameters of the main pulmonary and right interlobar arteries correlated with systolic pulmonary artery pressure (p < 0.001), as measured by right heart catheterization. In the patients affected with chronic thromboembolic pulmonary hypertension, the ratio of the calibers of the segmental arteries to the corresponding bronchi was markedly higher, which was observed also in the patients with acute pulmonary embolism. The bronchial arteries were dilated in 4 of 8 cases of chronic thromboembolic pulmonary hypertension. Lung density was significantly high in the perihilar compartment in the patients with acute thromboembolic hypertension, but not in normal controls and in the cases of acute pulmonary embolism. In conclusion, CT can help to diagnose pathological pulmonary circulation. Particularly, the ratio of the diameters of the segmental arteries to the corresponding bronchi can be useful to evaluate blood circulation.

[Diagnosis with high resolution computerized tomography of early asbestos-induced diseases]

This study was aimed at investigating the possibility of detecting lung and pleural asbestos-related lesions by means of conventional chest films and high-resolution Computed Tomography (HRCT) in a study population of asymptomatic workers of a shipyard factory in northwestern Tuscany, Italy. Thus, a blind study was carried out by two radiologists who reviewed 144 conventional chest films previously considered as negative by outside readers. Thirty-eight of 144 workers were selected, whose conventional films had been confirmed as negative, together with 34 more subjects with suspected pleural plaques or mild parenchymal involvement (ILO profusion score: 0/1). These 72 subjects were submitted to HRCT: 19 of them were negative, while in 33 cases pleural plaques were found; 7 workers exhibited parenchymal involvement alone, while in 13 both pleural and parenchymal alterations were found. HRCT findings were correlated with the duration of amosite exposure and the latency time since first exposure. Relative to conventional radiographs, the threshold of exposure and latency times allowing asbestos-related diseases to be demonstrated was markedly lower. Our study suggests that pleural and/or lung involvement in asbestos-exposed workers can be shown by HRCT before the onset of clinical symptoms or the appearance of pleural/parenchymal involvement on chest films. Moreover, the HRCT-detectable lung and/or parenchymal involvement appeared to be related to exposure and latency times, as in most of clinically-apparent asbestos-related lung diseases.

[The evaluation of a digital system for the automatic analysis of the density of abdominal radiograms]

This paper reports the results of the evaluation of an automatic system developed to analyze radiographic densities. This system, called RADEN, has been implemented at the Institute for Information Processing of the Italian National Research Council in Pisa. Forty-three pairs of abdominal X-ray films were obtained before and after the administration of ionic iodate contrast medium (i.i.c.m.) during urographic examinations. The 86 X-ray films were acquired and digitized using a computer-controlled optoelectronic device with a sampling step ranging 125 microns to 250 microns. The resulting images were arrays of 512 x 512 pixels, each one quantified on a byte (256 gray levels). The computing system included a high-performance personal computer equipped with a video RAM board having built-in facilities for image processing and with an optical disk to archive the images. Automatic and semi-automatic procedures were developed to segment, recognize and classify the images and to characterize three homogeneous regions--i.e., bone, water and air. The output data were compared with the area values of the air densities computed directly on the X-ray films by a radiologist. Furthermore, both data sets were compared with the scores given in a blind study by four observers. The subsequent statistic analysis showed the increase in air density areas after i.i.c.m. administration and the applicability of the implemented system to the automatic examination of abdominal radiographic densities. The results encourage to believe that the proposed approach could be employed as a first step for the development of quite a more complex system oriented to X-ray image understanding and to assisted diagnosis.

[The computed tomographic diagnosis of malignant pleural mesothelioma. A multicenter study]

CT features are described and accuracy of the method is discussed in the diagnosis of malignant pleural mesothelioma. Ninety-eight patients suffering from pleural disease mimicking mesothelioma were examined by means of III-generation CT scanners; according to the final diagnosis, 37 patients suffered from malignant pleural mesothelioma, 27 from other malignant pleural diseases and 34 from various benign diseases. In all patients a series of CT signs was evaluated: pleural thickening patterns, lesion spread and possible associated characters. In the diagnosis of mesothelioma CT showed 72.5% sensitivity, 63.8% specificity, 68.3% diagnostic accuracy, 68.5% positive predictive value and 68.2% negative predictive value. Some significant CT patterns in distinguishing malignant from benign pleural disease were identified, while the characterization of malignant disease (mesothelioma versus other neoplastic conditions) proved to be unreliable.