Characterization of benign hepatic tumors arising in fatty liver with SonoVue and pulse inversion US

BACKGROUND

We describe the spectrum of contrast-enhancement patterns of benign hepatic tumors arising in fatty liver on contrast-enhanced ultrasound (US).

METHODS

Sixteen patients (12 women and four men) with 27 benign hepatic tumors (17 hemangiomas, eight focal nodular hyperplasias, and two hepatocellular adenomas) arising in fatty liver underwent baseline and pulse inversion US after administration of SonoVue. Two experienced radiologists evaluated baseline echogenicity and dynamic enhancement pattern of each lesion in comparison with adjacent liver parenchyma.

RESULTS

After administration of SonoVue, in the arterial phase 13 of 17 hemangiomas showed peripheral globular enhancement and one showed a rim of peripheral enhancement, followed by progressive centripetal fill-in, which was complete in 10 of 14 cases and incomplete in four. Three of 18 hemangiomas showed rapid and complete fill-in in the arterial phase. Eight of eight focal nodular hyperplasias became hyperechoic in comparison with adjacent liver parenchyma in the arterial phase and slightly hyperechoic or isoechoic in the portal venous and delayed phases. Both adenomas showed strong arterial contrast enhancement that became less intense in the portal venous and delayed phases.

CONCLUSION

Contrast-enhanced US after administration of SonoVue enables depiction of typical contrast-enhancement patterns in most benign hepatic tumors arising in fatty liver, thus providing useful clues for characterization.

Pancreatic carcinoma versus chronic focal pancreatitis: contrast-enhanced power Doppler ultrasonography findings

BACKGROUND

We assessed the potential usefulness of contrast-enhanced power Doppler ultrasonography (US) for differentiating pancreatic carcinoma from chronic focal pancreatitis.

METHODS

Twenty-six consecutive patients with ductal carcinoma (n=16) and chronic focal pancreatitis (n=10) underwent power Doppler US examinations before and after intravenous injection of an air-based contrast agent (Levovist, Schering, Berlin, Germany). Final diagnosis was obtained by surgery in all patients. The following parameters before and after intravenous administration of contrast agent were evaluated for each lesion: number, morphology and course of the vessels within the lesion and time to maximum detectable enhancement. Number of the lesion vessels and time to maximum enhancement for each lesion were compared by with Student t test.

RESULTS

After injection of contrast agent, nine of 16 (56.2%) carcinomas showed a larger total number of vessels (p<0.005) and faster enhancement (p<0.0001) compared with chronic focal pancreatitis. Irregular vessels with a serpiginous course that penetrated the tumor was predominant in carcinoma (eight of 16 cases), whereas focal pancreatitis presented mostly as avascular masses (five of 10 cases).

CONCLUSION

Contrast-enhanced power Doppler US provides useful findings for differentiating pancreatic carcinoma from chronic focal pancreatitis.

Analysis of different contrast enhancement patterns after microbubble-based contrast agent injection in liver hemangiomas with atypical appearance on baseline scan

BACKGROUND

We describe different possible enhancement patterns in liver hemangiomas with atypical appearance on baseline ultrasound after microbubble-based contrast agent injection.

METHODS

From a series of 253 consecutive lesions that were indeterminate on baseline ultrasound and then scanned after injection of air-filled microbubble contrast agent, 65 focal liver lesions were retrospectively selected on the basis of a diagnosis of liver hemangioma on multiphase contrast-enhanced computed tomography (n = 23), magnetic resonance imaging (n = 27), or histology (n = 15). Each lesion was scanned during arterial phase (30 s after microbubble injection) and late phase (5 min after injection). On-site sonologists performed retrospective assessment of contrast-enhancement patterns by consensus.

RESULTS

Centripetal fill-in preceded (n = 50) or not preceded (n = 3) by peripheral nodular/rim-like enhancement was the prevalently observed contrast-enhancement pattern, equivalent to the typical enhancement pattern of liver hemangiomas on contrast-enhanced computed tomography or magnetic resonance imaging. In the remaining lesions, additional enhancement patterns (diffuse contrast enhancement with rapid fill-in and a late hyper-isoechoic appearance, n = 6; peripheral nodular enhancement with a late hypoechoic appearance, n = 3; or persistent heterogeneous and hyperechoic appearance, n = 3) were observed.

CONCLUSION

Different contrast-enhancement patterns are possible in atypical liver hemangiomas after microbubble injection. Typical centripetal fill-in is the prevalent pattern and its evidence allows diagnosis.

The Color Doppler with contrast agent US in the study of post Cholecistectomy Syndrome

PURPOSE

The aim of this study was to evaluate the study of intra- and extra-biliary ducts by contrast-enhanced colour-Doppler in patients who have undergone laparoscopic cholecystectomy.

MATERIALS AND METHODS

Contrast-enhanced colour-Doppler US was performed in 15 patients who had undegone laparoscopic cholecystectomy. The US contrast agent was introducted into the Kehr or Pedinelli tube to allow visualisation of the bile ducts and duodenum.

RESULTS

The colour-Doppler study enabled visualisation of the contrat agent in the intra- and extra-hepatic bile ducts and in the duodenum in all patients, thereby permitting the accurate study of the post-operative course. The data obtained were confirmed by conventional radiology.

CONCLUSIONS

The advantages of this US ultrasound technique are the complete absence of ionising radiation and no intolerance to the US contrast agent. This technique could therefore be used in selected patients as an alternative to trans-Kehr and trans-Pedinelli cholangyography.

Non-invasive assessment of coronary artery stent patency with multislice CT: preliminary experience

PURPOSE

To evaluate the diagnostic accuracy of multislice computed tomography coronary angiography (MSCT-CA) in the detection of in-stent restenosis.

MATERIALS AND METHODS

Forty-two patients (33 male, 9 female, mean age 58+/-8 years) previously subjected to percutaneous implantation of coronary stent with suspected in-stent restenosis, underwent a 16-row MSCT (Sensation 16, Siemens) examination. The average time between stent implantation and MSCT-CA was 7.4+/-5.3 months. The following scan parameters were used: collimation 16x0.75 mm, rotation time 0.42 s, feed 3.0 mm/rot., kV 120, mAs 500. After administration of iodinated contrast material (Iomeprol 400 mgI/ml, 100 ml at 4 ml/s) and bolus chaser (40 ml of saline at 4 ml/s) the scan was completed in <20 s. All segments with a stent were assessed by two observers in consensus and were graded according to the following scheme: patent stent, in-stent intimal hyperplasia (IIH) (lumen reduction <50%), in-stent restenosis (ISR) (=/>50%), in-stent occlusion (ISO) (100%). Consensus reading was compared with coronary angiography.

RESULTS

Forty-seven stents were assessed (16 in the right coronary artery; 4 in the left main; 22 in the left anterior descending; 5 in the circumflex). In 7 (17%) stents there was ISR (3) or ISO (4), and in 4 (10%) stents there was IIH. The sensitivity and negative predictive values for the detection of ISO were 80% and 98%, respectively, while for the detection of ISR+ISO they were 50% and 89%, respectively.

CONCLUSIONS

Although the results are encouraging, the follow-up of stent patency with MSCT-CA does not show a diagnostic accuracy suitable for clinical implementation.

MR findings in lipoma arborescens of the knee: our experience

PURPOSE

This paper describes the role of MR imaging in the identification of the different macroscopic patterns of lipoma arborescens.

MATERIALS AND METHODS

Between June 1995 and January 2004, a total of 6387 MR examinations of the knee were retrospectively assessed for the presence of lipoma arborescens. The MR examinations were performed using a superconductive 0.5 T MR unit with a transmitting/ receiving coil dedicated for the extremities. The MR images were acquired with SE T1-weighted, GE T2-weighted and STIR sequences in sagittal, coronal and axial planes with 3-mm thickness and 1-mm gap.

RESULTS

Lipoma arborescens was identified in 9 patients (mean age: 36 years). In 2/9 cases a localized lipoma arborescens was detected as a well-marginated single nodule on the suprapatellar bursa without irregularity or synovial hyperplasia. In the remaining 7 cases diffuse lipoma arborescens was identified on the wall of the suprapatellar bursa. In one case of diffuse lipoma arborescens there was involvement of both knees. In all cases the MR findings were verified at surgery and the final diagnosis was made by histological examination.

CONCLUSIONS

MR imaging shows a high accuracy in the identification and characterization of lipoma arborescens, due to its multiplanar capabilities and high contrast resolution. MRI allows correct evaluation of size and grade, accurate treatment planning and effective follow-up, avoiding the need for synovial biopsy.

Diagnostic accuracy of 16-row multislice CT angiography in the evaluation of coronary segments

PURPOSE

To evaluate the diagnostic accuracy of 16-row multislice spiral computed tomography coronary angiography (16-MSCT-CA) for the non-invasive assessment of significant coronary artery stenosis.

MATERIALS AND METHODS

We enrolled 40 patients (36 male, aged 59+/-11 yrs) with suspected obstructive coronary artery disease and a heart rate <65 bpm during the scan. The 16-MSCT-CA (Sensation 16, Siemens, Forchheim, Germany) was performed with electrocardiographically-gated technique after the intravenous administration of 100 ml of iodinated contrast material followed by a saline bolus chaser. The scan parameters were: collimation 16 x 0.75 mm, rotation time 0.42 s, feed/rot. 3 mm (pitch 0.25), 120 kVp, 500 mAs. All coronary segments = or >2 mm in diameter were evaluated by two independent observers for the presence of significant coronary artery stenosis (= or >50%). Consensus reading was compared to quantitative coronary angiography.

RESULTS

The average heart rate was 55+/-6 bpm. Of the 428 segments of = or >2.0 mm diameter 92 were significantly diseased. Without exclusion of any branches (428), the sensitivity, specificity, positive, and negative predictive values to identify = or >50% obstructed segments were 95.7% (88/92), 95.8% (322/336), 86.3% (88/102), and 98.8% (322/326), respectively. No occluded left main, left anterior descending, circumflex or right coronary artery segments remained undetected.

CONCLUSIONS

16-MSCT-CA in a selected low-heart-rate patient population provides high diagnostic accuracy in the evaluation of significant coronary artery stenosis.

Vesicoureteral reflux in young patients: comparison of voiding color Doppler US with echo enhancement versus voiding cystourethrography for diagnosis or exclusion

We assessed the accuracy of voiding color Doppler ultrasonography (US) with echo enhancement for diagnosis or exclusion of vesicoureteral reflux (VUR) versus voiding cystourethrography (VCUG) and evaluated patient tolerance of the echo-enhancing agent. One hundred twenty-two patients (ages range, 1 month to 17 years) with 244 ureterorenal units underwent voiding color Doppler US with echo enhancement, which was followed by VCUG on the same day. After US of the urinary tract, the bladder was filled with saline solution via catheter. Then an echo-enhancing agent was instilled, and color Doppler US was performed. Reflux was diagnosed when microbubbles appeared in the ureter or the pelvicaliceal system. VUR was detected in 98 units. All grades of reflux were identified. In 13 units (13.3%), grade I reflux diagnosed at voiding color Doppler US was not observed at VCUG. No reflux was detected in 146 units by either method. In 231 (94.2%) of the 244 ureterorenal units, there was concordance between the two methods. The echo-enhancing agent was well tolerated by all patients. Voiding color Doppler US with echo enhancement is useful for the diagnosis or exclusion of VUR, being as good as VCUG. Therefore, it may reduce the number of patients exposed to ionizing radiation.

Pigmented villonodular synovitis of the foot: MR findings

PURPOSE

To evaluate the MRI findings in the various forms of pigmented villonodular synovitis (PVNS) of the foot.

MATERIALS AND METHODS

Seven hundred and fifty-three MR studies of the foot performed at our institute between June 1994 and April 2000 were retrospectively reviewed for the presence of PVNS. Spin echo (SE) T1W, Gradient echo (GE) T2*W, and fat suppression (Short Time Inversion Recovery: STIR) images were acquired with a 0.5 T superconductive unit (Vectra, GE Medical System, Milwaukee, WI, USA) provided with a dedicated transmitter/receiver coil. The site and type of lesions, the signal intensity patterns, and the presence of associated changes were evaluated.

RESULTS

On the basis of the MR images and the above parameters, six patients (3 men, 3 women, age range: 35-48 years) with PVNS were selected. Three out of six PVNS were nodular, whereas the remaining three were diffuse. Of the three nodular forms, one was found in the sub-talar joint and the remaining two antero-medially to the talus. Instead, all of the diffuse lesions were located on the metatarsus. Perilesional oedema was seen in all cases, although more obvious in the nodular forms, whereas bone involvement (osteochondral erosion) was observed only in the diffuse metatarsal PVNS. Intra-articular bloody effusion was never observed. The MRI findings were confirmed by surgery in all cases.

DISCUSSION

The high contrast resolution and multiplanar capabilities of MRI allow the complete evaluation of the structures of the foot affected by PVNS, and of the extent of soft tissue (bursae, synovial or nervous structures), bone and articular involvement. Although not specific, the presence of haemosiderin results in characteristic MR findings, due to the shortening of both T1 and T2 relaxation times. GET2* images are particularly well suited to this

PURPOSE

Furthermore, in our experience, FIR images added better depiction of associated swelling.

CONCLUSIONS

According to our results, MRI is now the most reliable technique for identifying and classifying PVNS, and allows correct treatment planning and effective monitoring.

Pitfalls and limitations of Magnetic Resonance Imaging in bucket-handle tears of knee menisci

PURPOSE

The aim of the present study was to assess the accuracy of magnetic resonance imaging (MRI) in the diagnosis of bucket-handle tears of the knee menisci, determining the sensitivity and specificity of the imaging for each of the signs typical of these tears.

MATERIALS AND METHODS

MR examinations of 495 patients suffering from knee traumas were assessed retrospectively. Forty-eight patients had arthroscopically-proven bucket-handle tears of the meniscus. MR examinations were performed using a 0.5-T superconducting magnet, with T1-weighted spin-echo (SE) and gradient-echo (GE) T2*-weighted sequences. Imaging findings used for the diagnosis were: a) double posterior cruciate ligament sign; b) flipped meniscus sign; c) presence of a displaced fragment of the meniscus in the intercondylar notch, visible in coronal and axial images; d) truncated triangular shape of the peripheral non-displaced portion of the meniscus, visible in coronal images.

RESULTS

A total of 43 out of 48 bucket-handle tears of the meniscus were correctly diagnosed at MR, thus overall MR accuracy was 98%. In 12 (28%) cases three signs were present simultaneously the double posterior cruciate ligament (sensitivity 28%, specificity 99%, accuracy 93%) + the displaced fragment in the intercondylar notch (sensitivity 69.8%, specificity 98.7%, accuracy 96.2%) + the truncated triangular shape of the peripheral portion of the meniscus (sensitivity 74.4%, specificity 98%, accuracy 96%). In 18 (42%) cases two signs were present together the displaced fragment of the meniscus + the truncated triangular shape of the peripheral portion of the meniscus. In 13 (30%) cases only one sign was presenting two cases the truncated triangular shape of the peripheral portion of the meniscus and in 11 cases the flipped meniscus sign (sensitivity 25.6%, specificity 93.4%, accuracy 87.5%). No statistically significant differences were found comparing the results for tears of the medial meniscus with those for the lateral meniscus.

CONCLUSIONS

MR imaging is highly accurate in diagnosing bucket-handle tears of the menisci due to its ability to identify a displaced fragment of the meniscus in the intercondylar notch or flipped over the anterior horn of the meniscus of origin. We speculate that bucket-handle tears not found by MR imaging are cases where the meniscus was displaced after MR examination.

MR imaging of arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular displasia (ARVD) is a heart disease characterized by a total or partial fat replacement of the myocardium. Echocardiography, which has been most commonly used for the diagnosis of ARVD, usually only demonstrates right ventricular enlargement with associated hypokinesia and with normal left ventricular chamber size. Angiocardiography is very effective in the evaluation of ARVD, especially, in the detection of wall motion abnormalities and bulgings. However, angiocardiography is invasive. Magnetic resonance imaging is a non-invasive, repeatable technique, which allows a more accurate evaluation of the right ventricular chamber and free wall. Therefore MRI is very effective in the differentiation of the high signal intensity of the fat from other medium intensity tissue, such as muscle, and in detection of fibro-fatty replacement of myocardium. It provides an accurate assessment of right-chamber enlargement, right ventricle outflow tract ectasia and wall motion abnormalities by cine-MR GE technique.

[Sportsman hindfoot pain: role of magnetic resonance imaging]

PURPOSE

To assess the outcome of Magnetic Resonance Imaging (MRI) in the diagnosis of sportsman hindfoot pain.

MATERIALS AND METHODS

Fortythree professional athletes (31 men, 12 women, age range: 17-37 years) affected by hindfoot pain underwent MRI. Spin echo (SE) T1W, Gradient echo (GE) T2*W, and fat suppression (Short Time Inversion Recovery: STIR) images were acquired with a 0.5 T superconductive unit (Vectra, GE Medical System, Milwaukee, WI, USA). A dedicated extremities transmitter/receiver coil was used. The lesion site, the presence of anatomic variants (os trigonum, Haglund's deformity), and signal intensity changes were evaluated.

RESULTS

In all cases MRI allowed the identification of the cause of the hindfoot pain, in relation to soft tissue (bursae, synovial or nervous structures), bone and articular diseases. Particularly, as regards soft tissue diseases, tendinous abnormalities and inflammatory bursal involvement were frequently found (77% of cases). Bone diseases (22% of cases with posterior talalgia alone), mostly involved the heel (60%), whereas cartilagineous diseases were present in 9% of cases. In 60% of cases an intra-articular osseous or cartilagineous displaced fragment coexisted, determinating joint locking during foot flexo-extension movements. In 38% of cases contemporary involvement of different articular structures was observed.

DISCUSSION

Both MRI high contrast resolution and multiplanar capabilities allow the complete evaluation of hindfoot region. In our experience sagittal and axial planes were particularly well suited for the diagnosis and the assessment of disease extension. Furthermore, T2W (GET2*) and fat suppression (STIR) images allow high sensitivity even in early disease detection, when hyperemia or fluid collection occur.

CONCLUSIONS

According to our results, it seems possible to state that nowadays MRI is the most reliable technique for identifying the causes of hindfoot pain, in order to provide a correct and effective pre-therapeutic planning.

[Thrombolytic therapy in myocardial infarction. Computerized tomography of encephalic complications]

PURPOSE

To evaluate the CT findings of intracerebral hemorrhage in patients undergoing thrombolytic therapy for acute myocardial infarction and to correlate the type of intracerebral hemorrhage with clinical outcome.

MATERIAL AND METHODS

We retrospectively reviewed the clinical records and CT scans of intracerebral hemorrhage on a total of 302 patients who underwent thrombolytic therapy for acute myocardial infarction at our institution from January 1996 to September 1999. In each patient we evaluated: the number, sites and size of hemorrhage, and the presence and severity of mass effect. The site of the hemorrhage was classified as intraparenchymal, intraventricular, subdural and subarachnoid.

RESULTS

Six patients (2%, mean age 74, range 66-80) developed intracerebral hemorrhage. There was a total of 22 hemorrhages: 1 subdural hemorrhage, 6 subarachnoid, 11 intraparenchymal and 4 intraventricular. Excluding intraventricular hemorrhage, 14/18 hemorr-hages were located supratentorially. In five patients there was a fluid-blood level. Three patients had severe mass effect with midline shift. Symptoms presented within 24 hours from the administration of thrombolytic therapy in all patients. All the patients who died had a large hematoma with a severe mass effect and a severe midline shift at CT scan. In the remaining patients, the hematoma was of medium size and no mass effect was seen.

CONCLUSIONS

The most common site of hemorrhage was supratentorial and intraparenchymal. Large volume intracerebral hemorrhage, multiple hemorrhages and mass effect with midline shift were associated with increased mortality. The most commonly observed finding was a fluid-blood level hematoma.

[Usefulness of CT colonography in the preoperative evaluation of patients with distal occlusive colorectal carcinoma]

PURPOSE

To evaluate the role of preoperative virtual colonoscopy to study the proximal colon in patients with distal occlusive carcinomas, diagnosed by conventional colonoscopy.

MATERIAL AND METHODS

We examined 19 patients aged 46 to 83 years (13 men and 6 women) with distal occlusive colorectal carcinomas diagnosed by conventional colonoscopy, who were preoperatively studied with virtual colonoscopy. Patients with acute bowel obstruction were excluded. Results were compared with the findings of preoperative conventional colonoscopy and barium enema examination, intraoperative colon palpation, histopathologic outcome, postoperative conventional colonoscopy and barium enema examination.

RESULTS

Virtual colonoscopy identified all 19 distal occlusive colon carcinomas and 22 synchronous lesions, 2 cancers (prevalence 10,6%) and 20 polyps (prevalence 68,4%). Both synchronous cancers were confirmed intraoperatively by direct palpation. Postoperative conventional colonoscopy, which was performed in 18 patients, confirmed the presence of 15 polyps in 12 patients. Three subcentimeter polyps were removed during conventional colonoscopy and were missed at virtual colonoscopy. Two polyps shown by virtual colonoscopy were not found at conventional colonoscopy. Postoperative barium enema was performed in three patients and confirmed three polyps identified at virtual colonoscopy. Preoperative barium enema was performed in five patients and failed to adequately demonstrate the proximal colon. Virtual colonoscopy showed a sensitivity of 87% and a specificity of 75%.

CONCLUSIONS

Virtual CT colonoscopy can be considered an important diagnostic technique to evaluate preoperatively the proximal colon in patients with distal occlusive carcinomas,as it gives better results than barium enema or conventional colonoscopy, as well as being well tolerated and less invasive.

[Normal anatomy and pathological conditions of subscapular muscle: US findings compared with surgery]

PURPOSE

To compare US results with those of surgery in the assessment of the subscapularis tendon.

MATERIAL AND METHODS

From January 1995 to December 1998 1500 patients underwent US of the shoulder. 12 of these patients had an injured subscapularis tendon. US results of these patients were evaluated retrospectively and compared with those of surgery. US examinations of the subscapularis tendon were performed with two US units (AU4 Idea and HDI 3000), using linear arrays 10-13 MHz transducers. The following features of the tendon were evaluated: morphology, thickness and echotexture.

RESULTS

A) US findings. US showed: - chronic degenerative tendon changes with diffusely inhomogeneous echotexture (5 cases); - focal tears with small hypoechoic ill-defined areas or gross hypo-anechoic areas involving the full thickness of the tendon (4 cases); - complete tendon tear with disappearance on US of the subscapularis tendon or with severe thickening of the tendon (2 cases); - in 1 case of recent anterior dislocation of the shoulder a bulky hematoma was seen with coexisting thickening and subtotal tear of the tendon. B) Surgical findings. US findings were confirmerd at surgery in 10 of the 12 patients. In the patient with anterior dislocation of shoulder the diagnosis hematoma was confirmed, but the subscapularis tendon was undamaged. Moreover, in 1 out of the 5 patients with US diagnosis of chronic degenerative tendon changes, a small focal tear of the tendon was found at surgery.

CONCLUSION

US is a first level investigation which is able to demonstrate early changes of the subscapularis tendon and nearby structures. Awareness of pitfalls might decrease the use of second level investigations such as CT arthrography and MR imaging, which on the other hand allow a better definition and assessment of the extent of the injury.

[Benign hepatic tumors: MRI features before and after administration of superparamagnetic contrast media]

PURPOSE

To assess the yield of superparamagnetic iron oxide (SPIO)-enhanced MR images in the detection and characterization of benign hepatic tumors and to evaluate the potential role and safety of SPIO administration in the diagnosis of these tumors.

MATERIAL AND METHODS

Eighteen patients underwent MRI before and after administration of SPIO particles. Spin echo (SE) T1, DP, T2 and Gradient echo (GE) T2* images were acquired with a.5 T superconductive unit. MR diagnosis was bioptically proved in 12 patients. In the remaining six patients, who had hemangiomas only, diagnosis was confirmed by at least two imaging techniques-such as MR, CT, ultrasonography, radio-labeled red cells scintigraphy-and by both clinical and imaging follow-up.

RESULTS

Thirthy-four tumors were detected on the MR images: 29/34 (85,3%) before and 33/34 (97%) after SPIO administration - 6 focal nodular hyperplasias (FNH), 6 adenomas and 22 hemangiomas. One small tumor (adenoma) was detected on the unenhanced MR images only, while 4 lesions (3 adenomas, 1 FNH) were detected after SPIO administration only.

DISCUSSION

SPIO-enhanced MRI increased the detection rate of benign hepatic tumors compared to non-enhanced MRI. Iron oxide was also useful in the characterization of such lesions as it was able to demonstrate any heterogeneity resulting from the presence of central scars or septa. Nevertheless, in our experience it was useful to compare baseline with SPIO-enhanced MRI, even if time consuming. Indeed the uptake of iron oxide particles by well-differentiated lesions and normal hepatic parenchyma, is comparable, so that well-differentiated lesions appear isointense and therefore undetectable.

CONCLUSIONS

In our experience, although numerically limited, SPIO-enhanced MRI was clinically safe and more effective than non-enhanced MRI in both the detection and characterization of benign hepatic tumors, providing useful clues for diagnosis.

[Pre- and postoperative study of the bile ducts with spiral computerized tomography]

PURPOSE

To investigate the capabilities of Helical CT in imaging the biliary tract after administration of an oral cholecystographic contrast agent.

MATERIAL AND METHODS

Forty-five adult patients and one 8-year-old child were examined with Helical CT 12 hours after the oral administration of hyopanoic acid (3 g). All the examinations were performed with the following parameters: thickness 5 mm, pitch factor 1.5, standard reconstruction algorithm, acquisition time 20-30 s, image index 2.5 mm, 130 kV, 125 mA. In 37 cases CT was performed in patients candidate to laparoscopic cholecystectomy, in 8 cases to assess the positioning of surgical clips in patients with postcholecystectomy syndrome and in 1 case (the 8-year-old child) to confirm the US diagnosis of choledochal cystic dilatation. Helical CT images were reconstructed with a Volume Rendering (VR) software.

RESULTS

The extrahepatic biliary tract was visualized in all the cases with CT and VR. II grade biliary ducts were visualized in 87% (CT) and 91% (VR), III grade ducts in 76% (CT) and 78% (VR), IV grade ducts in 28% and 35%, respectively. No statistically significant difference was found between CT and VR in the visualization of the biliary structures (p > 0.05), while three-dimensional VR reconstructions improved the evaluation of the anatomical relations in the biliary tract in comparison with CT both in normal cases and in patients with congenital abnormalities of the biliary tract. Also, three-dimensional VR reconstructions were superior in assessing the correct positioning of surgical clips in patients with postcholecystectomy syndrome (p < 0.05).

DISCUSSION AND CONCLUSIONS

Cholecysto-cholangio-CT with VR reconstructions is a reliable imaging technique for the biliary tract in patients candidate to laparoscopic cholecystectomy, to diagnose choledochal cystic dilatation and to assess the positioning of surgical clips.