[CT and MRI features of Castleman's disease of the abdomen and pelvis].

OBJECTIVE: To analyze the CT/MRI features of Castleman's disease of the abdomen and pelvis. METHODS: CT/MRI images of 6 cases of pathologically confirmed Castleman's disease of the abdomen and pelvis were retrospectively reviewed. All the patients received plain CT scan and dynamic enhanced scan, and one had an additional MR scan. RESULTS: One case was identified as the disseminated type with multicentric enlarged lymph nodes and hepatosplenomegaly, and 5 cases were found to have localized type, of which 3 had retroperitoneal, 1 had mesentery and 1 had pelvic lesions. On CT scan, all the 5 cases with localized lesions showed single, round or ellipse soft tissue masses, with intra-tumoral calcification in 2 cases, fascial thickening around the mass in 3 cases, and satellite nodules in 4 cases. Enhanced scanning revealed obvious enhancement in the arterial phase and continuous enhancement in the portal vein and delayed phase in all the lesions, with an attenuation pattern similar to that of large vessels; enlarged blood vessels within or around the mass were displayed in each case. In 4 cases, the intra-tumoral radial or fissured non-enhanced areas in early stage of enhancement were gradually filled up as the scan time was delayed. The patient receiving MRI showed hypo-intensity on T(1)WI and hyper-intensity on T(2)WI, presenting with an enhancement feature similar to that of CT. CONCLUSION: Castleman's disease in the abdomen and pelvis is rare and liable to misdiagnosis, but its characteristic imaging features can help in the diagnosis and differential diagnosis.

[Computed tomography and magnetic resonance imaging features of desmoid-type fibromatosis: comparison with the pathological findings].

OBJECTIVE: To explore the computed tomography (CT) and magnetic resonance imaging (MRI) features of desmoid-type fibromatosis, and improve the diagnostic accuracy and understanding of the disease. METHODS: The CT and MRI features of 18 cases of surgically and pathologically confirmed desmoid-type fibromatosis were reviewed retrospectively. Among the patients, 10 received CT pre- and post-contrast scanning, and 8 patients had MRI pre- and post-contrast scanning. The CT and MRI features were analyzed in comparison with the pathological findings. RESULTS: In the extra abdominal cases, the tumors occurred in the head and neck in 3, in the dorsal part of the chest in 2, in the abdominal wall and groin area in 9, and in the peritoneal cavity in 4; concomitant Gardner syndrome was found in 1 case. In 4 cases the tumor occurred within 1 to 3 years after abdominal surgeries. Pathologically, the lesion was hard and composed of fusiform fibroblasts and myofibroblast. The cells showed no obvious heteromorphism with few karyokinesis, growing invasively and recurrent locally but without distant metastasis. Immunohistochemically, the fibroblasts and myofibroblasts expressed vimentin, and the myofibroblasts were positive for SMA. On CT and MRI, the lesion appeared benign with malignant growth pattern, and caused compression of the adjacent organs and vessels or encasement of the vessels; the border was unclear without encapsulation, and necrosis and calcification was scarce. The density and signal of the tumor were well distributed. Twelve patients displayed obvious enhancement and 5 showed uneven enhancement. CONCLUSION: The CT and MRI features of desmoid-type fibromatosis are characteristic, and CT and MRI are valuable modalities for the diagnosis and differential diagnosis of the tumor.

[Clinical study of transcatheter arterial chemoembolization plus radiofrequency ablation in hepatocellular carcinoma by magnetic resonance imaging and functional diffusion-weighted imaging].

OBJECTIVE: To evaluate the apparent diffusion coefficient (ADC) value features of the lesions after transcatheter arterial chemoembolization (TACE) plus radiofrequency ablation in hepatocellular carcinoma (HCC) with 3.0T magnetic resonance imaging (MRI) and diffusion-weight imaging (DWI) and analyze the value of 3.0T DWI in detecting the pathological lesion features of post-TACE plus radiofrequency ablation in HCC. METHODS: Twenty-eight HCC patients were enrolled to receive TACE firstly. Then all viable tumors around the lesions underwent radiofrequency ablation. At 1-4 months after radiofrequency ablation, 3.0T MRI and DWI (b = 600 sec/mm(2)) were performed to measure the ADC values of different lesions of post-TACE plus radiofrequency ablation. The features of MRI and ADC values of different lesions, the difference of contrast enhancement sequence and DWI in evaluating the lesions of post-TACE plus radiofrequency ablation were analyzed. RESULTS: Viable tumors occurred in 14 of 28 HCC patients after TACE plus radiofrequency ablation. The ADC values of necrotic tissues with lipiodol, necrotic tissues without lipiodol, viable tumors and normal liver tissues were 1.905 ± 0.487, 0.726 ± 0.116, 1.449 ± 0.054 and 1.777 ± 0.094 (10(-3) mm(2)/sec) respectively. There was no significant difference of ADC values between necrotic tissues with lipiodol and normal tissues (P = 0.115). But there were significant differences of ADC values among necrotic tissues with lipiodol, necrotic tissues without lipiodol and viable tumors (P < 0.05). The viable tumor tissues after TACE plus radiofrequency ablation appeared as nodular lesions with slightly heightened signal intensities around the necrotic tissues, the lesions with heterogeneous enhancement during arterial phase, portal vein phase and parenchymal phase. Necrotic tissues without lipiodol occurred outside necrotic tissues without lipiodol, around normal liver tissues, with low signal intensities on T2WI, without enhancement during arterial phase, portal vein phase and parenchymal phase. There were no significant difference between contrast enhancement and DWI sequence in detecting viable tumors after TACE plus radiofrequency ablation (P > 0.05). CONCLUSION: The ADC values of 3.0T MR DWI may be used to distinguish the viable residue or recurrent tumor tissues, necrotic tissues in HCC after TACE plus radiofrequency ablation.

Crohn disease of small bowel: multidetector row CT with CT enteroclysis, dynamic contrast enhancement, CT angiography, and 3D imaging.

BACKGROUND: CT could be used to evaluate abnormalities in the bowel wall, mesentery, adjacent structures, vasculature, and even the activity of Crohn disease (CD). To our knowledge, few direct comparisons of CD characterization using multidetector row CT with dynamic contrast enhancement, 3D imaging, CT angiography (CTA), and CT-enteroclysis (CT-E) on the same cohort of patients. The purpose of this study was to evaluate the diagnostic value of CD using multidetector helical CT with CT-E, dynamic contrast enhancement, 3D imaging, and CTA. METHODS: Twenty-eight patients known or suspected CD underwent CT-E, dynamic contract enhancement, CTA, and 3D imaging. The multidetector CT series images were performed on eight-slice CT scanner. All the examinations were performed when water was used as an oral contrast starting 25 s after 140 mL of intravenous contrast agent was administered, followed by portal venous phase (60 s), and a 60-70 s delay, then sending 1.25-mm slices to the 3D workstation, CT angiograms and 3D images were reconstructed. All the images were reviewed to detect abnormalities of CD. The abnormalities of the bowel wall, mucosal and submucosal ulceration, prominent perienteric vasculature, sinus tracts or fistulae, abscess were evaluated. RESULTS: Crohn disease was diagnosed in 28 patients by CT images, and 54 inflammatory segments were revealed. In active inflammatory cases, the diseased bowel wall thickened and the enhancement of diseased bowel wall increased significantly in 34 inflammatory segments of 22 cases, the enhancement of diseased bowel wall increased significantly but without the wall thickened in three patients. Prominent vasculature was found in CTA and 3D images in 21 patients with active diseases. In 16 patients, the sharp interface between bowel and mesentery was lost and the attenuation of fat increased. Sinus tracts or fistulae were observed in eight patients, four of 28 patients demonstrated abscesses, all were active inflammatory patients. In three chronic inflammatory patients, normal bowel, bowel lumen stricture, and the normal enhancement of the wall were displayed. CONCLUSION: The abnormalities of CD and its complications can be identified by multidetector CT with CT-E, dynamic enhancement, CTA, and 3D imaging, and they are important methods in diagnosing CD. Complications of CD can be shown better when CT-E is performed.