The costs of treatment of early and chronic Pseudomonas aeruginosa infection in cystic fibrosis patients.

The aim of cystic fibrosis (CF) care is to improve both the life expectancy and quality of life of patients. However, rising costs and limited resources of health services must be taken into account. There are many different antibiotic strategies for therapy of Pseudomonas aeruginosa infection in CF patients. In this 5-year retrospective study we found that the cost of treatment of initial infection is considerably lower than the cost of treating chronic P. aeruginosa infections. The percentage distribution of costs of antibiotic treatment in relationship to the administration route was considerably different between outpatients and inpatients. We observed an increase in antibiotic costs with the age of the patient and the decrease in FEV(1)values. The implementation of early eradication treatment, in addition to decreasing the prevalence of patients chronically infected by P. aeruginosa, might also bring about a notable decrease in costs.

Sweat testing in newborns positive to neonatal screening for cystic fibrosis.

Sweat chloride concentrations above 40 mmol/l are unusual in newborns screened for cystic fibrosis and should be followed up. Centiles of sweat chloride concentrations in newborns positive to cystic fibrosis neonatal screening are presented. There are no significant correlations between age at sweat testing and sweat chloride concentration or quantity of sweat collected.

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.

A computer science approach to managing security in health care.

The security of electronic medical information is very important for health care organisations, which have to ensure confidentiality, integrity and availability of the information provided. This paper will briefly outline the legal measures adopted by the European Community, Italy and the United States to regulate the use and disclosure of medical records. It will then go on to highlight how information technology can help to address these issues with special reference to the management of organisation policies. To this end, we will present a modelling example for the security policy of a radiological department.

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.

Clustering ECG complexes using hermite functions and self-organizing maps.

An integrated method for clustering of QRS complexes is presented which includes basis function representation and self-organizing neural networks (NN's). Each QRS complex is decomposed into Hermite basis functions and the resulting coefficients and width parameter are used to represent the complex. By means of this representation, unsupervised self-organizing NN's are employed to cluster the data into 25 groups. Using the MIT-BIH arrhythmia database, the resulting clusters are found to exhibit a very low degree of misclassification (1.5%). The integrated method outperforms, on the MIT-BIH database, both a published supervised learning method as well as a conventional template cross-correlation clustering method.

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.

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.

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.

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.

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.

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.

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]. / Utilità della Tecnica di Dixon modificata associata a somministrazione di gadolinio nella caratterizzazione delle masse surrenaliche.

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.