CT features of focal organizing pneumonia: an analysis of consecutive histopathologically confirmed 45 cases.

OBJECTIVE: To study the CT characteristics of solitary focal organizing pneumonia (FOP). MATERIALS AND METHODS: Chest CT of consecutive 45 patients (34 males and 11 females, median age: 56 years) with confirmed FOP were analyzed. The CT features between large FOP (>3 cm, n=27) and small FOP (≤ 3 cm, n=18) were compared. RESULTS: FOP lesions predominately located in peripheral lungs (86.7%), with the right lower lobe being most common lobe (44.4%). No lesion mainly located in the inner 1/3 of lungs. All large lesions were polygon in shape and had an irregular margin, while small lesions were more likely to be round or oval with an irregular or smooth border. Air bronchogram or small bubble-like lucency was present in majority of the lesions. 42.2% of lesions had incompact internal structure with inhomogeneous density besides air component. Most lesions were associated with a contraction or convergence of surrounding vessels; while no pulmonary vessel was interrupted abruptly by a small FOP lesion. Majority of large lesions had broad contact with the pleura, while only one patient had mild pleural effusion. Mild mediastinal lymph nodes enlargement was present in about 1/5 of the patients. CONCLUSION: Compared with the known CT features of lung cancer, our results suggest differential diagnosis can often be made for large FOP, while small FOP may resemble lung cancer.

Somatotopic reorganization of hand representation in bilateral arm amputees with or without special foot movement skill.

Bilateral arm amputees usually are excellent foot users. To explore the plasticity of the primary motor cortex in upper-extremities amputees and to determine if the acquisition of special foot movement skill is related with the bilateral hand amputation, we studied the primary motor cortex by using combined task and resting state functional magnetic resonance imaging (fMRI). We investigated 6 bilateral arm amputees with or without special foot movement skill. In the task fMRI study, we found that toe tapping of all the amputees activated the bilateral hand area, including cases without special foot skill. In addition, cases without special foot skill mainly activated the precentral gyrus, which differed from those with more adept foot motor skill who activated both the precentral and postcentral gyri. To further understand the plasticity of the hand area, the resting state functional connectivity was investigated between the foot and hand regions. One-tailed two-sample t-test suggested that the connections between two areas became significantly stronger in the amputee group. Our study demonstrates that hand region of the cortex does not remain 'silent' after bilateral arm amputation, but rather is recruited by other modalities such as adjacent or nonadjacent cortexes to process motor information in a functionally relevant manner. From the data presented, it seems that the bilateral arm amputees have a strong potential to develop new skills in their remaining extremities and practice may further enhance this potential.

CT and MR features of xanthogranulomatous cholecystitis: an analysis of consecutive 49 cases.

OBJECTIVE: To study the CT and MR features of xanthogranulomatous cholecystitis (XGC). MATERIALS AND METHODS: 49 patients had pathologically confirmed XGC. All patients underwent contrast enhanced CT, and 10 patients had additional plain MRI. The CT and MRI results were retrospectively analyzed. RESULTS: On CT, all patients had thickening of gallbladder wall, with 87.8% cases showed diffuse thickening. 85.7% cases had intramural hypo-attenuated nodules in the thickened wall. Continuous mucosal line and luminal surface enhancement were noted in 79.6% and 85.7% cases, respectively. Gallbladder stones were seen in 69.4% patients. The coexistence of the above 5 CT features was seen in 40% cases, and 80% cases had the coexistence of ≥ 4 features. Diffused gallbladder wall thickening in XGC is more likely to have disrupted mucosal line, and XGC with disrupted mucosal line is more likely to be associated with liver infiltration. In 60% patients the inflammatory process extended beyond gallbladder, with the interface between gallbladder and liver and/or the surrounding fat blurred. 40% cases had an early enhancement of liver parenchyma. Infiltration to other surrounding tissues included bowel (n=3), stomach (n=2), and abdominal wall (n=1). On MR images, 7 of 9 intramural nodules in 7 subjects with T1-weighted dual echo MR images showed higher signal intensity on in-phase images than out-of-phase images. CONCLUSION: Coexisting of diffuse gallbladder wall thickening, hypo-attenuated intramural nodules, continuous mucosal line, luminal surface enhancement, and gallbladder stone highly suggest XGC. XGC frequently infiltrate liver and surrounding fat. Chemical-shift MRI helps classifying intramural nodules in the gallbladder wall.

Image quality and dose performance of 80 kV low dose scan protocol in high-pitch spiral coronary CT angiography: feasibility study.

To investigate the image quality and dose performance of 80 kV high-pitch spiral (HPS) coronary CT angiography (CCTA). 106 patients consecutively enrolled into prospectively ECG-triggering HPS CCTA (pitch = 3.4) exam using kV/ref. mAs = 80/400, 100/370, and 120/370 when patient BMI was ≤22.5 (n = 40), between 22.5 and 27.5 (n = 53) and >27.5 kg/m² (n = 13). Image quality was assessed per-segment by two observers independently using a 4-point scale (1-excellent, 4-non-diagnosable). Image noise and signal-to-noise ratio (SNR), contrast-to-noise ratio were measured. Diagnostic image quality was obtained in 503 of 507, 687 of 693, 164 of 167 coronary segments in 80, 100, 120 kV groups without significant difference (P = 0.482). The proportions of segments with score 1-4 were not significantly different among three kV groups (all P > 0.05). Image noise were significantly higher in 80 kV group than 100 and 120 groups (P < 0.001), while SNR was not (P = 0.097). The effective dose of 80 kV group (0.36 ± 0.03 mSv) was significantly lower than that of 100 kV group (0.86 ± 0.08 mSv) and 120 kV group (1.77 ± 0.18 mSv). The mean ± SD of HR in all patients was 54.8 ± 5.1 bpm. 80 kV HPS CCTA is feasible for patient with BMI ≤ 22.5 kg/m² which can save 58% dose than 100 kV group, while maintain diagnosable image quality.

Bimodal visualization of colorectal uptake of nanoparticles in dimethylhydrazine-treated mice.

AIM: To investigate colorectal uptake of solid lipid nanoparticles (SLNs) in mice receiving different doses of 1,2-dimethylhydrazine (DMH) using magnetic resonance (MR) and laser-scanning confocal fluorescence microscope (LSCFM) imaging. METHODS: Eight mice were sacrificed in a pilot study to establish the experimental protocol and to visualize colorectal uptake of SLNs in normal mice. Gadopentetate dimeglumine and fluorescein isothiocyanate (FITC)-loaded SLN (Gd-FITC-SLN) enemas were performed on mice receiving DMH for 10 wk (group 1, n = 9) or 16 wk (group 2, n = 7) and FITC-SLN enema was performed on 4 DMH-treated mice (group 3). Pre- and post-enema MR examinations were made to visualize the air-inflated distal colorectum. Histological and LSCFM examinations were performed to verify colorectal malignancy and to track the distribution of SLNs. RESULTS: Homogeneous enhancement and dense fluorescence (FITC) deposition in colorectal wall were observed in normal mice and 1 DMH-treated mouse (group 1) on fluid attenuated inversion recovery (FLAIR) and LSCFM images, respectively. Heterogeneous mural enhancement was found in 6 mice (4 in group 1; 2 in group 2). No visible mural enhancement was observed in the other mice. LSCFM imaging revealed linear fluorescence deposition along the colorectal mucosa in all groups. Nine intraluminal masses and one prolapsed mass were detected by MR imaging with different enhancement modes and pathologies. Interstitial FITC deposition was identified where obvious enhancement was observed in FLAIR images. Bladder imaging agent accumulations were observed in 11 of 16 DMH-treated mice of groups 1 and 2. CONCLUSION: There are significant differences in colorectal uptake and distribution of SLNs between normal and DMH-treated mice, which may provide a new mechanism of contrast for MR colonography.

[White matter tractography by diffusion tensor imaging in prognosis of acute lacunar infarctions].

OBJECTIVE: To evaluate diffusion tensor tractography (DTT) of white matter in prognosis of acute lacunar infarctions. METHODS: Twenty-eight patients of pyramidal tract strokes at the acute phase (<3 days) with a marked motor defect were examined. Lesions were identified on diffusion weighted imaging and isotropic imaging of DTI, and infarctions and the tract were shown on the DTT images simultaneously. The anatomic location and pattern of the lesions were visualized on DTT, with regard of the corticospinal tract (CST), all patients were divided into three clinical subgroups: in Group 1 infarction lesions were close to CST, in Group 2 CST was partial involved, in Group 3 lesions centered in the pyramidal tract. Subsequently, they were compared with the National Institutes of Health Stroke Scale (NIHSS) scores at acute phase (<3 days), early chronic phase (8 approximately 14 days), and outcome(30 approximately 60 days). RESULT: NIHSS scores of Group 1(12/28) were not different with those of Group 2 (11/28) at the acute phase (U=-1.430, P>0.05), and NIHSS scores in Group 2 were significantly lower than those of Group 3(5/28) (U= -2.676, P <0.01). In the outcome, NIHSS scores of Group 1 were significantly lower than those of Group 2 (U= -2.501, P<0.05), NIHSS scores of Group 2 were significantly lower than those of Group 3 (U= -2.948, P<0.01). Among these three groups,Group 1 all had good recovery, Group 2 also had good recovery but sometimes with some mild motor disfunction, and Group 3 always had marked defect and minor improvement. Both rADC value and rFA value were induced in the acute lacunar infarctions. CONCLUSION: DTT is helpful in prognestic valuation of acute lacunar infarction by providing visualized stereo localization of CST and infarction lesions.

Coexistence of small cell neuroendocrine carcinoma and villous adenoma in the ampulla of Vater.

Small cell neuroendocrine carcinoma of the ampulla of Vater is extremely rare and different from the common ampullary adenocarcinoma. The ampullary adenoma is also a rare neoplasm and has the potential to develop an adenocarcinoma. Their coexistence has been rarely reported in the literature. We herein describe an unusual case of a small cell neuroendocrine carcinoma associated with a villous adenoma in the ampulla of Vater with emphasis on computed tomography (CT) and histopathological findings. We also discuss their clinical, histopathological and radiological features as well as possible histogenesis.

[Functional MRI study on thalamus activation induced by electrical stimulation of different intensities].

OBJECTIVE: To detect the activation pattern of the thalamus in human by the functional magnetic resonance imaging (fMRI) with the electrical stimulation of different intensities, and to explore the mechanism of this area in pain modulation. METHODS: Ten healthy right-handed volunteers were given different electrical stimulations of 1-, 2-, and 3- times pain threshold respectively. The whole-brain was scanned simultaneously by GE 1.5T magnetic resonance imaging system. The data were postprocessed by analysis of functional neuroimages (AFNI) to establish the regional activity maps of the thalamus. RESULTS: Patterns of functional activity showed a positive linear relationship between the activation signals and stimulation intensity in bilateral thalamus, whereas the BOLD signal of bilateral medial thalamus demonstrated that the curve was similar to the exponential function. Meanwhile, the activation in the contralateral lateral thalamus (cThl), but not the contralateral medial thalamus (cThm), was prominent compared with the corresponding ipsilateral subregions, and only the lateral thalamus displayed a contralateral biased representation while the medial thalamus lacked this property. CONCLUSION: Thalamus is one of the vital components in the pain modulation network, which can present spatial segregation activations with unique characteristics of stimulation intensity-response in each subregion. All the results are helpful to understand the crucial role of thalamus in processing the pain information.

[The value of spiral computed tomography in diagnosis of adult intussusception].

OBJECTIVE: To evaluate the value of spiral computed tomography (CT) in diagnosis of adult intussusception. METHODS: Sixty-eight patients with adult intussusception, 42 males and 28 females, aged 52.5 (30-82), with the course of 3 days-13 months, underwent plain CT scanning and biphase CT enhanced scanning of the abdomen. Operation was performed later. RESULTS: Sixty-six of the 68 patients (97.1%) were diagnosed as with intussusception by spiral CT. Direct signs of intussusception were shown in 66 patients: concentric circle sign in 66 cases, vessel involvement in 61 cases, and fat sign in 58 cases. And main indirect signs were shown in 19 cases: ring sign in 19 cases, ileus sign in 24 cases, and ascitic fluid sign in 4 cases. Other signs included mesenteric infiltration in 4 cases and retroperitoneal lymphadenectasis in 8 cases. Operation performed later showed an accurate rate of etiological diagnosis of intussusception by CT of 72.1%. CONCLUSION: Spiral CT has important value in diagnosis of adult intussusception and its etiology. The specific signs to diagnose adult intussusception are concentric circle sign, vessel involvement and fat sign.

[A report of 12 cases of primary pulmonary cryptococcosis].

OBJECTIVE: The purpose of this study was to analyze the chest CT findings of immunocompetent patients with primary pulmonary cryptococcosis and to evaluate the utility of CT-guided percutaneous biopsy in the diagnosis. METHODS: Chest CT scans of 12 immunocompetent patients with biopsy-proven primary pulmonary cryptococcosis were analyzed for the number of lesions, morphologic characteristics, distribution of parenchymal abnormalities, and the presence of lymphadenopathy and pleural effusion. Lung specimens were obtained by CT guided percutaneous biopsy (n = 9) and/or surgical resection (n = 7). A pulmonary pathologist reviewed the specimens. RESULTS: The main manifestations were classified into two patterns. Localized multiple mixed lesions (nodules and/or masses and/or consolidation) were found in 67% (8/12) of the cases, and single nodules were found in 33% (4/12). Associated findings included air bronchograms (n = 9), cavity (n = 2), and CT halo sign (n = 4). Lung specimens were obtained by CT guided percutaneous biopsy in 9 cases, of which 7 (78%) were confirmed by pathology. Seven cases recovered after treatment with fluconazole, but cryptococcal meningitis occurred in 1 case 5 month after single excision. CONCLUSIONS: Chest CT findings of primary pulmonary cryptococcosis in immunocompetent patients have a predominant pattern of localized multiple mixed lesions. CT guided percutaneous biopsy is helpful in confirming the diagnosis. Fluconazole is effective in the treatment of pulmonary cryptococcosis in these patients.

[Study on brain response to acupuncture by functional magnetic resonance imaging--observation on 14 healthy subjects].

OBJECTIVE: To observe the signal changes of brain functional area during needling Sanyinjiao (ST36), Zusanli (SP6) and Yanglingquan (GB34), the three acupoints in three different meridians, in human by functional magnetic resonance imaging (fMRI), in order to preliminary explore the neural mechanism of acupuncture. METHODS: Needling was complemented with 30 s of maneuver applying followed by 30 s of rest as a circle on an acupoint, and at the same time, fMRI was performed once 5 min and 12 s. Then the same program was repeated with the same mode on another acupoint, until ending the experiment. RESULTS: The commonly activated regions were postcentral gyrus and right inferior frontal gyrus when needling at ST36 and SP6, and the different activated areas included left inferior frontal gyrus, left insula, left inferior parietal lobule, left culmen, left middle temporal gyrus and left middle frontal gyrus, while no cortical signal enhanced region was found when needling at GB34. Signal weakened regions could be found when needling at all the three points, the commonly activated regions were bilateral parahippocampal, hippocampal, callosal gyrus, bilateral praecuneus and cerebellum. CONCLUSION: Brain response in special regions could be obtained by needling at different acupoints.

[Anterior cingulate cortex involving in pain modulation-an functional magnetic resonance imaging study].

OBJECTIVE: To investigate the functional activation patterns of the subregions of anterior cingulate cortex (ACC) in human to electrical stimulation of different intensity with functional Magnetic Resonance Imaging (fMRI) and probe the contribution of this area in pain modulation network. METHODS: 10 healthy right-handed volunteers were studied with different electrical intensity stimulation of 1-, 2-, or 3-time pain threshold. The fMRI data were collected by GE signa 1.5T MRI system and postprocessed with software of Analysis of Functional Neuroimages (AFNI) to generate the regional activation maps of ACC, furthermore, the distinctive characteristics of stimulation-BOLD signal in ACC subregions were analyzed according to the fMRI maps from the average of the 10 subjects. RESULTS: The anterior portion of ACC (aACC) showed moderate pain-attention-related activation but not statistically related to the strength of stimulation (average activated pixels of P1, P2, P3 amounted to 324, 429, 562 respectively). The BOLD signal showed a positive linear relation with the increasing stimulation at the dorsal-posterior portion of ACC (average activated pixels of P1, P2, P3 were 311, 964, 1414), which indicated stimulus intensity-dependent responses. The ventral-posterior area of ACC (vpACC) demonstrated pain intensity encoding because the BOLD signal had no significant difference during innocuous condition but displayed remarkable distinction during noxious stimulation in this area (average activated pixels of P1, P2, P3 were 324, 429, 562). CONCLUSION: Subregions in ACC may play a varied role in the network of pain modulation. Each area of ACC displays segregated activation patterns in response to electrical stimulation with different strength.

Functional magnetic resonance imaging study of writer's cramp.

BACKGROUND: Writer's cramp is a type of task specific idiopathic focal dystonia and has an incompletely understood pathophysiology. The present study utilized functional magnetic resonance imaging (fMRI) to investigate what type of brain activity correlates with writer's cramp and its physiological mechanism. METHODS: Ten patients with writer's cramp were age and gender matched with ten healthy control subjects in a block design. Subjects were scanned by fMRI while performing three consecutive, visually instructive, tasks with MR Vision 2000: (1) suppositional writing, (2) writing with finger and (3) writing with a pencil. Data was analysed using AFNI software for groups of patients and controls. RESULTS: The patients with writer's cramp showed significant activations of contralateral basal ganglion (especially the putamen), motor cortex (primary sensorimotor cortex, supplementary motor cortex, premotor cortex) and ipsilateral cerebellar hemisphere in writing with a pencil compared with controls; whereas there was no obvious difference between patients and controls during writing with finger. Furthermore, these differences exist in the subtractive activated maps for "writing with a pencil" minus "writing with finger" of patients, when the activation of subcortical area and insula in controls disappeared. CONCLUSIONS: Abnormal activations of contralateral basal ganglion, motor cortex and ipsilateral cerebellar hemisphere of the patients with writer's cramp suggest dysfunction of basal ganglion and subcortical-cortical loop might play a pathophysiological role in writer's cramp.

Solid-pseudopapillary tumor of the pancreas: CT and MRI features of 3 cases.

BACKGROUND: Solid-pseudopapillary tumor of the pancreas is a rather rare but low-grade malignant tumor with good prognosis after surgical excision. METHODS: In 3 patients with solid-pseudopapillary tumor of the pancreas which were proved pathologically, the imaging features (CT in all and MRI in one patient) of the tumor were analyzed. RESULTS: In the 3 female patients under 35-year-old who presented no jaundice, CT revealed that huge solid-cystic masses of the pancreatic head with calcification in one and slight dilation of the pancreatic duct in another, but without dilation of the bile duct system in all. MRI demonstrated mixed signal intensity on T1WI and T2WI of the mass in one patient. CT and MRI revealed obvious enhancement of the cystic wall and solid part of the masses. CONCLUSIONS: CT and MRI findings of solid-pseudopapillary tumor of the pancreas are characteristic, and the diagnosis can be made preoperatively with the combination of clinical features.

[Spiral computed tomography images of extraluminal type gastric stromal tumors].

OBJECTIVE: To evaluate the diagnostic value of spiral CT and its reconstruction techniques in the diagnosis of extraluminal type gastric stromal tumors. METHODS: The data of spiral CT performed 1 week before operation of 17 extraluminal type cases, 11 males and 6 females, aged 35.5 (13-67), from 33 patients of gastric stromal tumors proved by pathology and immunohistochemistry, were analyzed retrospectively. RESULTS: The accuracy rates of level diagnosis and qualitative diagnosis of extraluminal type gastric stromal tumor by spiral CT were 88.2% and 82.4% respectively. The main CT manifestations included: (1) extraluminal mass connected with the gastric wall, with round or lobulated margin and characteristic horn-like appearance and direct invasion, more than 5.0 cm in diameter; (2) inhomogeneous density of mass, including mild to moderate uneven enhancement in artery phase and obvious enhancement in vein and delay phase in 15 cases, and obvious enhancement in artery phase and decrease of enhancement in portal vein phases in 2 cases. (3) Irregular niches and sinus in the margins of the intraluminal masses (n = 11) and unclear border of the masses and invasion into nearby structures (n = 9); (4) connection of the tumor and stomach wall by broad boundary or failure to distinguish the tumor and stomach wall; and (5) invasion to the surrounding tissues and organs as a sign of malignant tumors. CONCLUSION: Spiral CT and its reconstruction techniques have important value in level diagnosis and qualitative diagnosis of extraluminal type gastric stromal tumors.

[Researching the character and stenosis of coronary calcified plaques by using 16-slice spiral CT].

OBJECTIVE: To explore the characters of coronary calcified plaques by using 16-slice spiral CT and determine their stenosis degree according to the results of catheter coronary angiography. METHODS: Twenty patients who had received 16-slice spiral CT coronary angiography and conventional coronary angiography (CAG) were found to be with calcified plaques. The characters of these plaques, including the diameter of calcified plaques and lumen diameter of the exact artery segment, were retrospectively analyzed. The stenosis degree of the corresponding segment was judged in accordance with the results of CAG. RESULTS: Totally 84 calcified plaques were observed in 16-slice spiral CT images in these 20 patients. Among them there were 16 small nodules (diameter: < 0.15 cm), 56 purely calcified plaques (diameter: > or = 0. 15 cm), and 12 complex plaques with calcify component. There was no obvious stenosis in artery segments with little calcified nodules. The stenosis degree of most segments with purely calcified plaques (75%) was less than 50%. The stenosis degree had no significant correlation with the size of plaques (P > 0.05). However, the stenosis degree of complex plaques had much closer relationship with the characters of mixed plaques. CONCLUSIONS: Most coronary segments with calcified plaques have slight stenosis. Their stenosis degree is not related with the size of plaques. The stenosis degree of complex plaques has a closer relationship with the characters of mixed plaques.

[Diagnostic value of spiral computed tomography in adhesive ileus].

OBJECTIVE: To discuss the diagnostic value of spiral computed tomography (CT) in adhesive ileus. METHODS: We retrospectively analyzed 40 patients with adhesive ileus who were diagnosed by CT and confirmed by operations. The main reconstruction method included multi-planar reconstruction (MPR) and sliding thin slab-maximum intensity projection (STS-MIP). RESULTS: Among all the 40 patients, localization diagnosis was correct in 32 patients (80%) and partially correct in 8 patients (20%). The main signs included: (1) dilated proximal intestinal canal and collapsed distal intestinal canal in 40 patients (100%); (2) smooth transitional zone in 39 patients (97.5%); (3) delayed enhancement of regional bowel in 33 patients (82.5%); (4) beak sign in 32 patients (80%); (5) adhesions balteum in 6 patients (15%); and (6) pseudotumor appearance in one patient (2.5%). CONCLUSION: Spiral CT has an important value in detecting adhesive ileus.

[MRI diagnosis of benign sacrococcygeal teratomas of the infants].

OBJECTIVE: To investigate the value of MR imaging in the diagnosis of benign sacrococcygeal teratomas of the infants. METHODS: MR imaging of benign sacrococcygeal teratomas in 6 cases proved by surgery and pathology was retrospectively reviewed. In all patients, a fast imaging sequence, fast spin echo sequence was employed, together with short time inversion recovery sequence and contrast enhancement scanning by intravenous injection of Gd-DTPA. RESULTS: There were 6 benign sacrococcygeal teratomas, which were heterogeneous masses and arose from the distal sacrococcygeal region in the pelvis. The MR imaging appearances of the benign sacrococcygeal teratomas were characteristic, T1- and T2-weighted images demonstrated a large mass containing round, well-defined areas of varying signal intensity representing its cystic, solid, and sometimes fat, calcification within the lesions. CONCLUSION: MR imaging provides definitive information of benign sacrococcygeal teratomas and clearly shows both extra-and intra-pelvic components, and even better anatomic details, which facilitates the surgical planning adequately.

[Angiographic diagnosis of gastrointestinal stromal tumors].

OBJECTIVE: To investigate the angiographic feature and its diagnostic value in gastrointestinal stromal tumor (GIST). METHODS: Twelve patients with pathologically proved GIST underwent angiography using PUCK and DSA one week before operation. The origin, size, morphology and angiographic appearance of the lesion were retrospectively analyzed. RESULTS: It was found that two tumors originated from stomach, eight from jejunum, and two from ileum. Seven cases were benign but five malignant. Obviously thickened and enlarged feeding artery was detected in eight tumors, and early-developed vein was found in three. Two types of angiographic changes of GIST were observed: 1) twisted irregular neoplastic vessels with partially coarse and indistinct margin were found in four cases, which were all malignant; 2) ball-like neoplastic vessels with homogeneous stain in tumor were found in eight cases, seven of them were benign but one was malignant. CONCLUSION: Angiography may be helpful in localization and diagnosis as well as defining the size of GIST, and especially in patients with melena of unknown origin.