Gianvincenzo Sparacia

Focal Confluent Fibrosis in Cirrhotic Liver : Natural History Studied with Serial CT

OBJECTIVE The objective of this study was to assess the long-term natural history of focal confluent fibrosis in cirrhotic liver with CT. MATERIALS AND METHODS Two radiologists retrospectively reviewed in consensus 118 liver CT examinations in 26 patients (19 men, seven women; age range, 32-68 years; mean age, 50 years) performed over approximately 6 years. Helical CT scans were obtained before and 30-35 and 65-70 seconds after injection of 125-150 mL of contrast medium at a rate of 4-5 mL/s. Proof of cirrhosis was based on liver transplantation (n = 6), biopsy (n = 9), or imaging findings (n = 11). The number, location, and attenuation of fibrotic lesions and presence of trapped vessels were evaluated. Variation of hepatic retraction associated with the development of focal confluent fibrosis lesions was assessed using the ellipsoid volume formula and an arbitrary retraction index. RESULTS Each radiologist identified 41 focal confluent fibrosis lesions. All lesions were identified by both radiologists. Twelve patients (46%) had a single lesion, 13 (50%) had two lesions, and one (4%) had three lesions. Thirty-four (83%) of 41 lesions were located in segment IV, VII, or VIII. Thirty-two lesions (78%) were hypoattenuating on unenhanced images, 25 lesions (61%) were hypoattenuating on hepatic arterial phase images, and 20 lesions (49%) were isoattenuating on portal venous phase images. Seven lesions (17%) were or became hyperattenuating at follow-up on portal venous phase images. Trapped vessels were found in six lesions (15%). The retraction index showed a significant increase over time (r = 0.423, p < or = 0.0001). CONCLUSION The degree of capsule retraction associated with focal confluent fibrosis evolves with time and relates to the natural evolution of cirrhosis.

Perfusion CT in acute stroke: predictive value of perfusion parameters in assessing tissue viability versus infarction

Purpose.The aim of this study was to assess the value of computed tomography (CT) perfusion parameters in differentiating tissue viability in acute stoke patients.Materials and methods.Thirteen patients (mean age 63.3 years) with nonhaemorrhagic stroke underwent multidetector perfusion CT within 3 h of symptom onset. Images were continuously acquired at the basal ganglia over 40 s during injection of 90 ml of iodinated contrast medium injected at a rate of 9 ml/s with a 9-s delay. Z-axis coverage was 20 mm. All patients underwent diffusion-weighted magnetic resonance imaging (DWI) within 12 h of perfusion CT to define the extent of the infarct. Perfusion CT data were analysed in regions of interests (ROIs) on regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF) and mean transit time (MTT) maps placed in various parts of the perfusiondeficient territory and in the contralateral hemisphere. Statistical analysis was performed using the analysis of variance (ANOVA) test to assess differences in CT perfusion parameters. Receiver operator characteristics (ROC) analysis was performed to assess possible threshold values that predict tissue infarction vs. viability.Results.Normal CT findings with abnormal CT perfusion parameters were seen in the region of infarction and in the viable tissue (penumbra) within a 1.5-cm distance from the infarct margin as outlined on DWI images. Infarcted areas demonstrated significant prolongation of MTT values compared with noninfarcted areas (p<0.0001). Average MTT was 9.8 s in areas of infarction, 5.1 s in the viable tissue adjacent to the infarct (penumbra), and 3.4 s in the contralateral control area. An MTT threshold level of 6.05 s has a 100% positive predictive value (sensitivity 84.6%, specificity 100%, accuracy 92.3%) for the presence of infarcted tissue. Average rCBF was 24.6 ml/100 g per min in infarcted tissue, 64.8 in penumbra and 70.8 in normal tissue. Average rCBV was 3.5 ml/100g in infarcted tissue, 3.9 in penumbra and 2.9 in normal tissue.Conclusions.Prolongation of MTT was the most frequent CT perfusion finding observed in acute stroke patients. Average MTT values of 5.1 s may distinguish viable tissue, whereas MTT values >6.05 s identify infarcted tissue.

Reversible MRI abnormalities in an unusual paediatric presentation of Wernicke's encephalopathy.

Background. We report an unusual paediatric presentation of acute Wernickes encephalopathy in a 12-year-old boy affected by chronic gastrointestinal disease. MRI demonstrated, in addition to the typical diencephalic and mesencephalic signal abnormalities on T2-weighted images, enhancement of the mammillary bodies and the floor of the hypothalamus. Materials and methods. Following parenteral administration of thiamine for 4 days, the patient recovered from his neurological deficits and on follow-up enhanced MRI 1 month later, no signal abnormalities were found nor was there diencephalic or mesencephalic atrophy, as is usual in the chronic phase of the disease. Results. MRI provides crucial information in the diagnosis of Wernickes encephalopathy, either in the acute or chronic phases of the disease. Conclusion. Our report provides an additional clue for recognition of the acute phase of the disease; enhancement of the floor of the hypothalamus has not previously been described despite its recorded involvement at autopsy.

Magnetic resonance imaging of the pituitary gland in patients with secondary hypogonadism due to transfusional hemochromatosis

To identify pituitary iron overload in patients with transfusional hemochromatosis causing secondary hypogonadism, we prospectively evaluated signal intensity abnormalities of the anterior lobe of the pituitary gland of 18 patients affected by transfusion-dependent thalassemia major and secondary hypogonadism. Magnetic resonance (MR) imaging is useful to assess pituitary iron overload in patients with transfusional hemochromatosis and secondary hypogonadism by detection of a significant decreased signal intensity of the anterior lobe of the pituitary gland on GRE T2*-weighted images. The decreased signal intensity of the anterior lobe of the pituitary gland on GRE T2*-weighted images was correlated to increasing serum ferritin level (r=−0.84,r2=−0.70,P<0.001). Indeed, the lower the signal intensity of the pituitary gland the greater the serum ferritin level. However an exact quantification of pituitary iron overload by correlation with serum ferritin level is not allowed. No correlation was found between MR imaging results and hormonal status; however, the detection of pituitary iron overload on GRE T2*-weighted images is consistent with the hypothesis of hypogonadotrophic pituitary insufficiency due to iron-induced cellular damage.

Retroaortic left renal vein joining the left common iliac vein

Abstract. 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 °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.

Magnetic resonance findings in scuba diving-related spinal cord decompression sickness

Scuba diving is associated with risk of severe decompression sickness (DCS type II), which results from rapid reduction of the environmental pressure sufficient to cause the formation into tissue or blood of inert gas bubbles previously loaded within tissues as a soluble phase. DCS type II constitutes a unique subset of ischemic insults to the central nervous system (CNS) with primarily involvement of the spinal cord. Ten patients with diving-related barotrauma underwent neurologic examination. Two of them presented progressive sensory and motor loss in the extremities at admission and were presumed affected by spinal cord DCS. Magnetic resonance imaging (MRI) demonstrated abnormalities in the white-matter tracts of the spinal cord in these patients, in each case corresponding to an area of the cord believed to be clinically involved. After a course of therapeutic recompressions, one patient was able to stand and walk a short distance,and MRI revealed a decreased extension of areas of spinal cord abnormalities. MRI has proved to be reliable in the detection of pathologic changes of spinal cord decompression sickness that were previously undetectable by other neuroimaging methods and also has proved to be useful in the follow-up during therapeutic hyperbaric recompressions.

Imaging processing for CT angiography of the cervicocranial arteries: evaluation of reformatting technique

Purpose.The aim of this study was to compare computed tomography angiography (CTA) sliding-thin-slab (STS) multiplanar reformatting (MPR), STS maximum intensity projection (MIP) and three-dimensional (3D) volume rendering (VR) reformatting techniques in the evaluation of cervicocranial arteries.Materials and methods.Twenty patients examined with multislice CT were included in this study. CTA images were reformatted as STS-MIP, STS-MPR and 3DVR in orthogonal planes and in the oblique-coronal plane. Images were evaluated in consensus by two radiologists, with a third radiologist to resolve discordances in grading image quality parameters. The Spearman correlation analysis was performed to compare results and to obtain the correlation between scores resulting from the evaluation of parameters considered with the different techniques used (STSMIP, STS-MPR and 3DVR).Results.STS-MIP images were significantly superior to STSMPR images for all parameters considered (p<0.05). Obliquecoronal 3DVR images were significantly superior to obliquecoronal STS-MIP images in the evaluation of vertebrobasilar vessels (p<0.05); in all other cases, 3DVR images were equivalent to STS-MIP images.Conclusion.STS-MIP images should be the primary reformatting technique for CTA of the cervicocranial arteries in addition to viewing the source images; 3DVR images can play an important role after a previsional diagnosis is made on the STS-MIP images.

Brain damage in hanging : a new CT finding

Abstract We report a 23-year-old man who attempted suicide by hanging. There have been few reports of involvement of the brain parenchyma shown on CT, all showing ischaemic lesions. This is the first report of multifocal intracerebral haematomas due to hanging seen¶on CT.

Hamartoma of the urinary bladder: case report and review of the literature

Abstract. Bladder hamartoma is a rare benign entity with only eight cases reported in the literature thus far, and whose general imaging features have not, to our knowledge, been previously discussed. The purpose of this report is to review the literature and to discuss the imaging findings in one case of bladder hamartoma where US features were those of an inhomogeneous solid mass with an unechogenic center, which was in accordance with the CT findings of a soft tissue mass with central inhomogeneous enhancement due to central necrosis.

Gastrointestinal stromal tumour: 40-row multislice computed tomography findings

Purpose.The purpose of this study was to describe the findings and evaluate the role of multidetector (40–slice) computed tomography (MDCT) in the preoperative assessment of gastrointestinal stromal tumours (GISTs).Materials and methods.Thirteen patients with histologically proven GIST (size: 4–30 cm; mean: 9 cm) underwent 40–slice MDCT after the ingestion of 1,000 ml of water. Images were obtained before and 70 s after intravenous injection of 120 ml of iodinated contrast agent. Two experienced radiologists reviewed the CT findings to evaluate lesion site, size, margins, attenuation, growth pattern, enhancement pattern, ascites, lymphadenopathy, direct invasion to adjacent organs and distant metastasis. Multiplanar maximum intensity projection and three–dimensional (3D) reconstructions were also obtained.Results.Seven out of 13 GISTs were located in the jejunumileum, 3/13 in the stomach, 2/13 in the rectum and in one case, the origin remained unknown. Eleven out of 13 were exophytic, and ten had well–defined borders. Two out of 13 showed calcifications. Thirteen out of 13 exhibited inhomogeneous enhancement due to areas of necrosis and cystic degeneration. Direct invasion to adjacent organs (n=3), ascites (n=3), and liver (n=1) and peritoneal (n=1) metastases were also detected. Bowel obstruction, vascular invasion and lymphadenopathy were never seen.Conclusions.MDCT allowed reliable preoperative assessment of GIST, providing useful clues for lesion characterisation.