Objective: The objective of this study was to determine the incidence of typical and atypical enhancement patterns of hepatocellular carcinomas (HCCs) on multiphasic multidetector row CT (MDCT) and to correlate the enhancement patterns and morphological image findings of HCC with the degree of tumour differentiation. Methods: MDCT images of 217 patients with 243 surgically proven HCCs were evaluated through consensus reading by two radiologists. Our MDCT protocol was composed of precontrast, arterial, portal and delayed phases. The reviewers analysed the CT images for degree of attenuation; relative timing of washout; presence of dysmorphic intratumoral vessels, aneurysms and necrosis; tumour size; tumour margin; presence of pseudocapsule; intratumoral heterogeneity; and determined enhancement pattern. The imaging features were correlated with tumour differentiation using Fisher's exact test or the x 2 test. Results: Among 243 HCCs, 137 (56.4%) showed the typical enhancement pattern of HCC, which is arterial enhancement and washout on portal or equilibrium phase images. In the arterial phase, 190 of 243 (78.2%) HCCs showed hypervascularity, with approximately three quarters of poorly differentiated (PD) (34 of 45, 75.6%) and moderately differentiated (MD) HCCs (92 of 123, 74.8%) showing washout during the portal or delayed phases, vs only 50% of well-differentiated (WD) HCCs (11 of 22; p,0.048). The presence of intratumoral vessels and aneurysms, tumour necrosis, attenuation of precontrast, the relative timing of washout, intratumoral attenuation heterogeneity, tumour margin and tumour size were correlated with the pathological differentiation of HCCs (p,0.05). Conclusion: A typical enhancement of HCCs on MDCT was not unusual (43.6%) and WD and PD HCCs account for most of the atypical enhancement patterns. Early washout favoured MD and PD HCCs rather than WD HCCs, whereas in our study the presence of intratumoral aneurysm was a highly specific finding for PD HCC.

UVB irradiation concomitantly promotes epidermal proliferation and differentiation. Responses were maximal 48 h after irradiation. This effect of UVB increases linearly according to dose and repetition.

In this study, FTc predicted fluid responsiveness. However, FTc should be used in conjunction with other clinical information.

Study design: Review and analysis of seven cases of syringomyelia treated surgically. Objective: To demonstrate the bene®cial role of decompressive surgery for the altered cerebrospinal¯uid (CSF)¯ow dynamics in syringomyelia not associated with Chiari I malformation. A comparison between the pre-and post-operative syrinx size and CSF¯ow in the subarachnoid space was made using cine-mode magnetic resonance imaging (cine-MRI) and then correlated with clinical improvement. Setting: University Hospital, Seoul, Korea. Methods: Conventional spinal MRI and cine-MRI were performed in the region of CSF¯ow obstruction preoperatively in seven patients with syringomyelia not associated with Chiari I malformation. The group consisted of one case of syrinx with post-traumatic compression fracture, one case of post-traumatic arachnoiditis, two cases of holocord syrinx associated with hydrocephalus without Chiari malformation, one case of syrinx with post-traumatic pseudomeningeal cyst, one case of post-laminectomy kyphosis-associated syringomyelia and one case of post-tuberculous arachnoiditis syringomyelia. Based on the preoperative cine-MRI, the types of surgery appropriate to correct the CSF¯ow obstruction were chosen: decompressive laminectomy-adhesiolysis and augmentation duraplasty in arachnoiditis cases, ventriculoperitoneal shunt for hydrocephalus, cyst extirpation in pseudomeningeal cyst and both anterior and posterior decompression-fusion in the case of post-laminectomy kyphosis. A syrinx-draining shunt operation was performed in three cases; where the syringomyelia was associated with posttraumatic compression fracture refractory to a previous decompression, where hydrocephalus was present in which the decompression by ventriculoperitoneal shunt was insu cient and where post-traumatic arachnoiditis was present in which the decompression was impossible due to di use adhesion. Change in syrinx size was evaluated with post-operative MRI in all seven cases and restoration of¯ow dynamics was evaluated with cine-MRI in three of the cases, two patients with clinical improvement and one patient with no change of clinical status, respectively. Results: Four out of seven patients showed symptomatic improvement after each decompressive operation. In the remaining three cases, reconstruction of the spinal subarachnoid space was not possible due to di use adhesion or was not the main problem as in the patient with syrinx associated with hydrocephalus who had to undergo a shunt operation. One of these three patients showed clinical improvement after undergoing syringosubarachnoid shunt. A decrease of syrinx size was observed in only two out of the ®ve patients who showed clinical improvement after treatment. Of these ®ve patients, two patients underwent post-operative cine-MRI and the restoration of normal CSF¯ow dynamics was noted in both patients. Of the remaining two patients, one underwent post-operative cine-MRI and there was no change in the CSF¯ow dynamics evident. Conclusion: These results suggest that the restoration of ...

Yu JS, Lee JH, Chung JJ, Kim JH, Kim KW. Small hypervascular hepatocellular carcinoma: limited value of portal and delayed phases on dynamic magnetic resonance imaging. Acta Radiol 2008;49:735Á743.Background: Characterization of small nodules in the cirrhotic liver is always challenging in clinical practice. In the differential diagnosis of small hypervascular lesions, it has been reported that portal venous or delayed hypointensity is a useful sign to characterize hepatocellular carcinomas (HCCs) during dynamic magnetic resonance (MR) imaging. However, few studies have assessed the diagnostic value of this sign. Purpose: To determine the diagnostic value of portal-phase (PP) and delayed-phase (DP) images for the diagnosis of small hypervascular HCCs during intravenous (IV) contrastenhanced dynamic MR imaging of cirrhotic liver. Material and Methods: A total of 69 small (6Á20 mm) hypervascular HCCs in 53 cirrhotic patients were subjected to a retrospective analysis of the signal intensities (hypo-, iso-, or hyperintense) and rim enhancement on PP and 5-min DP images from three-phased dynamic MR imaging according to the pre-contrast T1-and T2-weighted imaging features. After exclusion of 33 subcapsular wedge-shaped pseudolesions and three hemangiomas by typical imaging features, 74 centrally located small hypervascular benign or pseudolesions were used as a control group for comparative analyses. Results: The sensitivities of PP hypointensity, DP hypointensity, and rim enhancement in the diagnosis were 11%, 29%, and 18%, respectively, for 6Á10-mm hypervascular HCCs, and 42%, 63%, and 58%, respectively, for 16Á20-mm lesions. After exclusion of the 48 lesions showing T2-weighted hyperintensity (HCCs, n039; benign lesions, n09), the overall sensitivity for diagnosis of small hypervascular HCCs decreased (8.3%, 25.0%, and 8.3%, respectively). Conclusion: Although DP provides a better sensitivity than PP, both PP and DP have very limited diagnostic value for diagnosis of small hypervascular HCCs during dynamic MR imaging of the cirrhotic liver.