[Adult intestinal intussusception: comparison between CT features and surgical findings]. / L'invaginazione intestinale dell'adulto: confronto tra aspetti TC e reperti chirurgici.

PURPOSE: To report our experience in the use of CT in the evaluation of adult intestinal intussusception. A correlation between radiologic findings and surgery was attempted in order to verify our diagnostic hypothesis. MATERIAL AND METHODS: Intestinal intussusception was diagnosed by CT between September 1993 and December 2000 in 10 patients (6 men and 4 women, age range 18-82 years). For 9/10 patients the diagnosis was confirmed by surgery; in one patient the condition resolved spontaneously as confirmed by a follow-up CT performed 24 hours after the first. Six patients were studied by a third generation CT and four by a helical CT unit. Five patients were administered iodinated oral contrast medium and in seven i.v. iodinated contrast medium. Diagnosis was hypothesized at CT on the basis of the following aspects: target, sausage, and pseudokidney. RESULTS: Surgery confirmed the CT diagnosis of intussusception in 9/10 patients; in the patient with transient intussusception a spontaneous resolution was confirmed at follow up CT after 24 h. In the 10 patients studied the following CT aspects were observed in the bowel involved by intussusception: a target aspect in 4 patients; a sausage aspect in 4 patients; in one of them a peritoneal effusion was also present; a pseudokidney aspect was observed in 2 patients, with a long tract intussusception and peritoneal adipose tissue; in both a hyperdensity of the peritoneal adipose tissue and enlarged vessels, that were herniated within the lumen of the bowel, were recognized. At surgey the causes of intestinal intussusception were: malignant tumors of the colon (4 cases), hamartomatous polyps of the small bowel (2 cases), mixoid fibrolipoma of the colon (one case), leiomyoma of the distal ileum (one case). In one patient no cause could be identified at CT, but the condition was found to co-exist with acute appendicitis at surgery. CONCLUSIONS: CT is an accurate technique in the evaluation of intestinal intussusception in adults. It allows to identify the condition, its site, and sometimes the type of the lesion causing the intussusception, and any vascular alteration, thus playing an important role in establishing the most appropriate therapeutic strategy.

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.

Retroaortic left renal vein joining the left common iliac vein.

Retroaortic left renal vein joining the left common iliac vein is a rare congenital anomaly in the development of the inferior vena cava. To our knowledge, only one case has been reported in the literature; however, its imaging features have never been described. A 27-year-old male presented with a 1-year history of recurrent right flank pain, dysuria, hematuria, and fever (39 degrees C). Computed tomography and MR venography showed a retroaortic left renal vein joining the left common iliac vein. We present the CT and MR venography findings and discuss their feasibility in showing this congenital anomaly.

[Os trigonum tarsi syndrome. Role of magnetic resonance]. / Sindrome dell'os trigonum tarsi. Ruolo della Risonanza Magnetica.

INTRODUCTION: The os trigonum tarsi is an accessory bone of the foot localized posterolateral to the lateral tubercle of talus. It is usually an asymptomatic condition. However, particular activities such as ballet, soccer, or football may cause repeated stress and chronic microtraumas to the hindfoot, resulting in the os trigonum syndrome. Pain is typically localized anterior to the Achilles tendon; nevertheless, diagnosis may be very difficult because other conditions may show the same symptoms. Radiography can only demonstrate the os trigonum and its morphostructural changes, while MR imaging can also depict associated soft tissue damage. We report on 9 cases of os trigonum tarsi syndrome studied with MR imaging. MATERIAL AND METHODS: Nine patients with the os trigonum tarsi syndrome were submitted to MRI. All the examinations were performed with the patients in supine recumbency with the injured foot in neutral position and then in forced plantar flexion. Axial and sagittal T1 SE, T2* GE and FIR images were acquired. We evaluated os trigonum location and shape, signal intensity of bone, cartilages and adjacent soft tissues, and possible associated tendon injuries. RESULTS: No changes were found in the os trigonum location and shape. Signal intensity changes were seen in 2/9 cases. Particularly, a small area of very high signal intensity, due to necrosis, was depicted on the talar aspect in 1 case; a subchondral spot of slightly increased signal intensity, with a low-signal outline, was seen on the calcanear aspect in another case. Disruption of the cartilaginous synchondrosis between the accessory navicular bone and the posterior tibial aspect was observed in 7/9 patients. Tenosynovitis of the flexor hallucis longus was associated in 6/9 patients. Pseudoarthrosis with irregular bone margins and high-signal spots within the cartilage was found in 3 cases. Finally, fluid effusion surrounding the os trigonum and adjacent soft tissues was always detected. DISCUSSION AND CONCLUSIONS: The os trigonum syndrome may result from chronic microtraumas. Indeed, forced plantar flexion may cause os trigonum compression between the posterior aspect of the tibial malleolus and the calcaneus, with disruption of the synchondrosis with the lateral tubercle of talus. Joint inflammation may be associated with possible development of pseudoarthrosis. Other possible complications are related to vascular changes which may lead to bone necrosis. Furthermore, the particular anatomical site of the os trigonum may sometimes cause compression to the flexor hallucis longus tendon, resulting in severe tenosynovitis. MR imaging allows complete morphostructural assessment because it depicts the margins and the signal intensity of bone and ligaments on the 3 spatial planes. Particularly, sagittal T2 images best demonstrate the cartilage changes indicating synchondrosis disruption. This condition may cause abnormal mobility of the accessory bone with possible impingement with the posterior aspect of the tibia, or hypomobility due to pseudoarthrosis. Forced plantar flexion acquisitions are particularly useful in this condition because they can demonstrate the mechanism of injury.

[Color Doppler-echo in rheumatoid arthritis with extra-articular location. Preliminary experience]. / L'eco color Doppler nell'artrite reumatoide con localizzazione extra-articolare. Esperienza preliminare.

INTRODUCTION: Chronic inflammation in rheumatoid arthritis usually involves articular synovia and extends to other joint components such as bursae, tendons and sheaths. Conventional US with high frequency transducers is an accurate tool for assessing abnormal changes in evolutive rheumatoid arthritis. We investigated the role of color and power Doppler imaging in staging extra-articular involvement, monitoring local inflammatory changes and drug treatment response. MATERIAL AND METHODS: We used a color Doppler unit with a 5-10 Mhz transducer and automatic power Doppler switch to examine 23 patients with tenosynovitis of the flexor (4/23) and extensor (8/23) tendons of the hand, Achilles (6/23) and posterior tibial (3/23) tendons, and long head of biceps (2/23) in acute rheumatoid arthritis. Only minimal pressure was exerted with the probe on the patients' skin to avoid compression and collapse of blood vessels. Ten normal volunteers were also examined as a control group. RESULTS: In all 23 acute rheumatoid arthritis patients, conventional US showed tendon involvement with intra-articular fluid, thickened tendons with partial tear and markedly hypoechoic thickened sheaths. Color signals were shown in all patients. Mid-caliber vessels were visualized coursing straight from the sheath deep into the tendon. Intra-articular signals were seen in 10/12 patients only. Spectral analysis showed arterial flow, with RI ranging .40-.70. Power Doppler added no important information, but improved vessel depiction relative to color Doppler thanks to its higher accuracy in detecting flow signals. There were no color signals in the tendons of the 10 healthy volunteers in the control group. No color signals were seen in both joints and tendons in 12 patients submitted to medical treatment. CONCLUSION: Color and power Doppler can be a necessary and useful integration to high resolution US for flow mapping in rheumatoid arthritis patients with tendon and extra-articular involvement. These modes depict local circulation changes related to disease stage and treatment response.

MR imaging of pancreatic changes in patients with transfusion-dependent beta-thalassemia major.

OBJECTIVE: The aim of this study was to evaluate MR imaging changes of the pancreas in patients with transfusion-dependent beta-thalassemia major. SUBJECTS AND METHODS: Twenty patients with transfusion-dependent beta-thalassemia major were examined using MR imaging at 0.5 T, with spin-echo T1-weighted, fast spin-echo T2-weighted, and gradient-echo T2*-weighted sequences. Image analysis was performed to assess pancreas-to-fat signal intensity ratios for all pulse sequences. Pancreatic exocrine and endocrine function and serum ferritin levels were assessed. Twenty healthy volunteers underwent MR imaging with the same three sequences and served as a control group. RESULTS: The pancreas-to-fat signal intensity ratio was significantly decreased in 17 (85%) of the 20 patients on spin-echo T1-weighted images (p < .05), fast spin-echo T2-weighted images (p < .01), and gradient-echo T2*-weighted images (p < .01) when compared with the 20 volunteers in the control group. The pancreas-to-fat signal intensity ratio was significantly increased in three (15%) of the 20 patients on spin-echo T1-weighted images (p < .01) and fast spin-echo T2-weighted images (p < .05). In addition, in the 20 patients, we found a significant correlation between increased pancreas-to-fat signal intensity ratios and decreased serum trypsin levels (r = -.77, p < .01 for spin-echo T1-weighted sequences; r = -.75, p < .05 for fast spin-echo T2-weighted sequences; and r = -.74, p < .05 for gradient-echo T2*-weighted sequences). Likewise, for the 20 patients, we found a significant correlation between decreased pancreas-to-fat signal intensity ratios and increased serum ferritin levels for gradient-echo T2*-weighted images (r = -.65, p < .01). No correlation was found for the other clinical parameters evaluated. CONCLUSION: MR imaging revealed signal intensity changes in the pancreas of patients with transfusion-dependent beta-thalassemia major. Patients with a major impairment of the exocrine pancreatic function had higher signal intensity of the pancreas because of fatty replacement of the parenchyma.

[The liver in patients with beta-thalassemia major. Determination of iron levels with magnetic resonance]. / Il fegato nei pazienti affetti da beta-talassemia major. Determinazione della concentrazione di ferro con Risonanza Magnetica.

INTRODUCTION: We investigated the clinical usefulness of liver MRI in a large multicenter study because the control of iron concentration (LIC) is crucial in thalassemia major (TM) prognosis and conflicting results have been reported in small and heterogeneous groups of patients using Magnetic Resonance Imaging (MRI), the only very common non-invasive procedure. MATERIAL AND METHODS: One hundred and eight consecutive TM patients, selected according to a specific protocol, were included in the study. In 29 of these LIC was measured by atomic absorption spectrophotometry on liver biopsy and expressed as microgram/gr dry weight. MRI was performed with a 0.5 T superconducting unit. The ratio of the average signal intensity (SIR) of the liver to that of paraspinal muscle was calculated and expressed as a percentage. RESULTS: Mean +/- (SD) of SIR was 100 +/- 26% (test for normality: p = 0.02) and of LIC was 3677 +/- 4662 micrograms/g/dry liver (test for normality: p < 0.00001). The logit transformation of LIC (lLIC) achieved both normality of distribution of lLIC and linear regression of lLIC on SIR (t = 7.36; p < 0.00001) according to the equation: Y = -0.0136 + SIR* (0.157) = lLIC log10 (K-LIC/LIC) where K = 79.433. Thus the values of LIC are expressed by the equation LIC K/(1 + 10 y) micrograms/g/dry liver. Moreover, a mild correlation was found between SIR and AST (p = 0.01; r = -0.30), ALT (p = 0.02; r = -0.21), gamma GT (p = < 0.01; r = -0.37; r = -0.25). CONCLUSIONS: This study shows that LIC can be calculated as a function of SIR. A validation study is necessary before introducing this prediction rule in clinical practice.

Right aortic arch with aberrant left innominate artery: MR imaging findings.

A rare case of a 60-year-old man with a right aortic arch and aberrant left innominate artery is presented. This case had an unusual clinical presentation. The dysphagia appeared suddenly in adulthood, whereas vascular rings, when symptomatic, usually manifest early in childhood. To our knowledge, MR imaging findings of this anomaly have never been reported. The diagnosis was made by MR imaging and confirmed by surgery. Magnetic resonance imaging can replace angiography in the assessment of the aortic arch anomalies.

[Magnetic resonance imaging of seronegative sacroiliitis]. / Studio delle sacro-ileiti sieronegative con Risonanza Magnetica.

INTRODUCTION: The inflammatory involvement of the sacroiliac joint is frequent during seronegative spondylarthritis. The clinical diagnosis of sacroiliitis may be very difficult, especially in the early stage, because joint motion cannot be assessed directly and the clinical picture is very similar to that of lumbar pain. Conventional radiography is negative as long as the structural change in the joint is limited to the synovial membrane and the cartilage (early stage). Computed Tomography (CT) also has many drawbacks, and thus the changes can be shown only when chondritis and enthesitis have already damaged the bone. The disease onset is usually preceded by a long latency; early diagnosis is needed for a proper and timely treatment, which can be made only with a highly sensitive and specific technique. We investigated the diagnostic accuracy of MRI in the early detection of sacroiliitis during seronegative spondylarthritis. MATERIAL AND METHODS: Forty patients with suspected sacroiliitis and negative radiographic findings were submitted to MRI; thirty-seven of them were HLA B27 positive. MRI was performed with a .5 T superconducting unit; T1-weighted SE, T2-weighted FSE, T2* GE, and STIR images were acquired on the oblique coronal plane parallel to the anterior sacrum. Ten asymptomatic volunteers were also examined as a control group. RESULTS: An irregular sacral border and marrow changes at the insertion of the sacroiliac ligaments were seen in 3/10 asymptomatic volunteers. MRI was negative in 7/40 patients, while the synovial compartment was replaced by some tissue with low signal intensity of T1 and high signal on T2 in the other 33 patients; this finding was referred to synovial pannus. Persisting low-signal foci were seen in the synovial compartment in 16/33 patients, which were referred to spared cartilage. High-signal regions were depicted at the bone periphery in 9/33 patients, which areas were consistent with bone erosion; the subchondral bone was markedly hypointense in 5 of these patients, indicating sclerosis. Finally, diffuse high signal intensity was found in the bone marrow in 3/33 patients and referred to infectious sacroiliitis. CONCLUSIONS: MRI appears the method of choice for the early detection of seronegative sacroiliitis because it can show the early changes in cartilage and subchondral bone, filling the gap between the onset of symptoms and radiographic evidence. Moreover, MRI uses no ionizing radiations and makes therefore a precious tool for the diagnosis and follow-up of young patients, hopefully decreasing the use of CT which however provides better detailing of bone and bone degeneration.

[The assessment of skin tumors with magnetic resonance with high resolution and a paramagnetic contrast medium]. / Valutazione dei tumori cutanei con Risonanza Magnetica con elevata risoluzione e mezzo di contrasto paramagnetico.

INTRODUCTION: The technologic improvement of surface coils in MRI has allowed better visualization of the skin and thus permitted the clinical use of this technique in dermatology. MRI allows to assess the depth and extent of skin tumors and to detect any malignant transformation. The MR differentiation between benign and malignant skin lesions relies on morphological criteria which however do not have an absolute diagnostic value. We investigated the role of paramagnetic contrast agents in the differentiation between benign and malignant skin lesions. MATERIAL AND METHODS: Forty-one patients, 33 with benign and 8 with malignant skin tumors, were submitted to MRI. All the examinations were performed with a 1.5 T superconductive unit, with a 2.5 cm surface coil. Axial T1- and T2-weighted SE images were acquired with 2 mm slice thickness. Paramagnetic contrast material was administered to all patients. The signal intensity of the skin lesions was calculated before and after paramagnetic contrast agent administration positioning a region of interest. A percentage ratio of contrast enhancement was calculated to quantify contrast agent uptake and the relative values were compared between benign and malignant lesions. A qualitative analysis was also performed rating the contrast enhancement of each lesion as high, intermediate, or absent. RESULTS: The quantitative analysis showed a statistically significant difference (p < .5) between the contrast enhancement values of benign and malignant lesions. In particular, malignancies had values ranging 117.3 (+/- 28.7) to 125 (+/- 32.4), while benign lesions had -20.6 to 99.8 (+/- 21.1). Conversely, no difference in contrast enhancement was found at qualitative analysis. CONCLUSIONS: MRI is a promising tool for characterizing skin tumors. Our preliminary results should be confirmed on larger series of patients with the use of high temporal resolution imaging sequences.

[Focal liver lesions. A comparison between magnetic resonance under base conditions and after a superparamagentic contrast medium]. / Studio delle lesioni focali epatiche. Confronto tra Risonanza Magnetica in condizioni di base e dopo mezzo di contrasto superparamagnetico.

INTRODUCTION: Superparamagnetic iron oxide (Spio) is a negative contrast material which is phagocytosed by reticuloendothelial cells. It significantly decreases the signal intensity of the organs where it is taken up selectively, especially on T2-weighted images. According to previous reports, it improves the visualization of focal liver lesions with(out) a low content of Kupffer's cells. We investigated the yield of Spio-enhanced MRI in the detection and characterization of focal liver lesions. MATERIALS AND METHODS: Eighteen patients underwent MRI before and after the administration of Spio particles. T1, PD, T2 SE and T2* GE images were acquired with a .5 T superconductive unit. The Spio dose was .075 mL/kg which was administered i.v. in 35-45 minutes' infusions. Images were acquired about 30-90 minutes after the end of administration. Scanning was repeated in one patient about 8 hours after the end of Spio administration. RESULTS: Baseline MRI showed hepatocellular carcinoma (HCC) in 10 patients, metastases in 4, 1 dysplastic lesion, 1 single and 1 multiple hemangioma, 1 focal nodular hyperplasia (FNH) and 1 intrahepatic cholangiocarcinoma. No lesion was detected in one patient. Spio-enhanced MRI detected 7 more lesions that baseline MRI, with 11.47% sensitivity improvement. Moreover, Spio-enhanced MRI detected more lesions that baseline MRI in 5/18 patients (27.78%). PD/T2 SE images were the most sensitive ones, followed by T2* GE and finally by T1 SE. Nearly all HCC nodules (17/18), all metastatic lesions and the cholangiocarcinoma did not take up iron oxide and were relatively hyperintense to the liver. However, in one well-differentiated HCC, the nodule partially took up the contrast agent and became isointense, with high-signal borders on PD/T2 SE images. Both the dysplastic lesion and FNH took up iron oxide; the former was isointense to the liver, while the latter appeared slightly hyperintense, with a high-signal central scar. Finally, hemangiomas became hyperintense on Spio-enhanced T1 SE images and had slightly decreased signal intensity on Spio-enhanced T2 SE images. CONCLUSIONS: In our experience iron oxide was an effective contrast material. Spio-enhanced MRI improved the detection and characterization of focal liver lesions relative to baseline MRI. Several liver-specific contrast agents are now available or in an advanced experimental stage. Therefore, future studies could be aimed at assessing the effectiveness of iron oxide versus other contrast agents and at establishing the role of Spio-enhanced MRI versus spiral CT and CT during arterial portography.

Monitoring treatment response with color and power Doppler.

Color and power Doppler are now widely used to monitor treatment response because of the latest technologic advances and of the increasing use of echo-enhancing agents. The assessment of treatment response is based on the amount of necrosis obtained and changes in local vascularization indicate a successful treatment. To date, clinical experiences have mainly concerned the treatment of hepatocellular carcinomas, hyperfunctioning nodules of the thyroid and parathyroid glands and the neoadjuvant chemotherapy of breast cancer. Aim of this review is to describe the role and potentials of color and power Doppler in this field. Hepatocellular carcinomas are currently treated with surgery or percutaneous ethanol injection and/or chemoembolization. Treatment response can be monitored with color Doppler: after a successful treatment, color signals are no longer detectable on color Doppler images. Conversely, the presence of arterial signals indicates persistent viable tumor. Unfortunately, color Doppler is limited when the hepatocellular carcinoma is hypovascular, small or deep. Echo-enhancing agents may help overcome these limitations, although spiral computed tomography or dynamic magnetic resonance imaging cannot be replaced yet in the definitive assessment of tumor necrosis. Color and power Doppler are well-established tools in the study of functioning thyroid and parathyroid adenomas after percutaneous ethanol injection. Echo-enhancing agents may improve Doppler sensitivity in the detection of residual viable tissue. Other interesting applications of color and power Doppler in this field are secondary hyperparathyroidism and hyperfunctioning thyreopathies (Graves' disease) treated with mercaptoimidazole. The evaluation of systolic flow velocity in the inferior thyroid artery is more reliable than the quantitative analysis of color signals in monitoring treatment response in Graves' disease. In our experience, systolic velocity in the inferior thyroid artery decreased from 150-250 to 60-80 cm/s after medical therapy. Finally, Doppler studies have provided good results in the follow-up of breast cancers after neoadjuvant therapy. In our experience on 18 patients treated with local parenteral repeated administration of antiblastic drugs, sonography showed no more signals within the lesion in 16 patients at the end of therapy. In the remaining two cases with persistent tumor at ultrasound, some color spots were still present and histopathology confirmed residual tumor cells. In conclusion, the results of color and power Doppler are encouraging. Thus, we believe that Doppler will be increasingly used in monitoring treatment response.