4D-CT angiography with arterial- and venous-phase anatomical pre-surgical approaches in cases with head and neck neoplasms.

PURPOSE: The relationship between neoplasm and its surrounding vascular structure is essential to the following clinical treatment plan. In this study, 4D computed tomography angiography (4D-CTA) with a wide scan range and dynamic phases of arteriography and venography was used to describe detailed anatomical information for pre-surgical approaches. MATERIALS AND METHODS: From January 2011 to February 2012, we subjected 13 patients with head and neck neoplasms to 4D-CTA. 4D-CTA was performed by a multidetector computed tomography (MDCT) scanner of 320 detectors. The parameters were set to a 0.5 mm section thickness, at 0.5 second per rotation, 80 kV and 150 mA. The scan range was set depending on the tumor size, with a maximal setting of 16 cm. A 30 mL contrast medium with 60 mL saline was injected at the rate of 5-7 mL per second based on the vascular patency, scanning every 2 seconds from the 16th to the 28th second after contrast injection. RESULTS: The vasculature surrounding the tumors was successfully illustrated in all cases. The 4D-CTA provided detailed vascular information that was compatible with the surgical and angiographic findings. CONCLUSION: 4D-CTA with a wide scan range and precise injection timing methods facilitated an anatomical approach to tumor-related vascular structures, providing detailed vascular information. This non-invasive technique may be useful for evaluating neoplasms and developing treatment plans, as an alternative to conventional angiography.

Pulmonary sequelae in convalescent patients after severe acute respiratory syndrome: evaluation with thin-section CT.

PURPOSE: To prospectively evaluate lung parenchyma on paired inspiration-expiration thin-section computed tomographic (CT) scans in patients recovering from severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: After the institutional review board approved the study and written consent was obtained from patients, 40 patients (25 female, 15 male; mean age, 42.8 years +/- 12.3 [standard deviation]) underwent thin-section CT at 51.8 days +/- 20.2 after onset of SARS symptoms. Twenty of the 40 patients underwent follow-up thin-section CT at 140.7 days +/- 26.7 after symptom onset. Lung findings were scored according to extent and then grouped in three categories (ground-glass opacity, interstitial opacity, and air trapping) for analysis. Mean CT scores for each finding in the various patient subgroups were compared by using the Mann-Whitney test. Clinical parameters and scores were evaluated for correlation by using Spearman rank correlation analysis. Mean scores for each finding were compared between the two serial examinations by using the Wilcoxon matched-pairs signed rank test. RESULTS: Air trapping, ground-glass opacity, and reticulation were found in 37 (92%), 36 (90%), and 28 (70%) of 40 patients, respectively, at initial thin-section CT examination and in 16 (80%), 14 (70%), and 10 (50%) of 20 patients, respectively, at follow-up examination. Scans from patients with adult respiratory distress syndrome (ARDS) had a significantly higher score for ground-glass opacity than did those from patients without ARDS (P = .009). A comparison of scores for the serial thin-section CT examinations indicated a significant reduction in the extent of ground-glass opacity (P < .001) and interstitial opacity (P < .001) but not in that of air trapping (P = .38) at follow-up examination. At initial thin-section CT, scores for ground-glass opacity, interstitial opacity, and air trapping correlated with age; those for ground-glass opacity and air trapping, with peak C-reactive protein level. At the second examination, scores for ground-glass opacity and interstitial opacity correlated with peak lactate dehydrogenase level; that for air trapping, with age and peak C-reactive protein level. CONCLUSION: Thin-section CT scores correlated with clinical and laboratory parameters in patients after SARS. Although ground-glass opacity and interstitial opacity resolve over time, air trapping persists.

Cerebral diffusion tensor images in children with tuberous sclerosis: a preliminary report.

BACKGROUND: In tuberous sclerosis (TS), tubers usually involve the white matter. Diffusion tensor (DT) images are used to demonstrate white-matter tracts. OBJECTIVE: To determine the changes in DT indices in supratentorial tubers and associated changes in the white-matter tracts adjacent to tubers in patients with TS. MATERIALS AND METHODS: The DT imaging indices, including first, second and third eigenvalues (EVs), apparent diffusion coefficients (ADCs), and fractional anisotropy (FA) in the white-matter lesions of tubers, were assessed in seven patients with TS exhibiting developmental delay and compared with controls. RESULTS: EV1, EV2, EV3, ADC and FA of the white-matter lesions of tubers were significantly different from contralateral unremarkable regions of the brain and from controls (P<0.05). The number of frontal and parietal tubers was significantly negatively correlated with EV1 of the superior longitudinal fasciculi of TS patients (r=-0.60, P =0.04). In addition, TS patients had significantly larger ADCs in the corona radiata and sagittal stratum than the control subjects. EV3s of the inferior longitudinal fasciculus and sagittal stratum were significantly more increased in the TS patients than in the control subjects. CONCLUSIONS: EV1, EV2, EV3, ADC and FA maps are potential tools for demonstrating cerebral white-matter changes owing to TS.

18-fluoro-2-deoxyglucose positron emission tomography in detecting residual/recurrent nasopharyngeal carcinomas and comparison with magnetic resonance imaging.

BACKGROUND: It is known that 18-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) is effective in the early detection of residual/recurrent nasopharyngeal carcinomas (NPC). To compare FDG-PET with the conventional magnetic resonance imaging (MRI) for the detection of residual/recurrent NPC, the authors studied 67 follow-up cases of patients with NPC using both FDG-PET and MRI. METHODS: From February 1997 to February 2001, 67 NPC patients (14 women, 53 men; age range, 16-67 years; mean age, 46.6 +/- 12.5 years) were recruited. Both FDG-PET and MRI of the head and neck area for each patient were performed at least 4 months (duration range, 4-70 months; mean, 14 +/- 13.5 months) after radiotherapy or radiotherapy with concurrent chemotherapy. The final diagnosis was confirmed by biopsy or clinical follow-up for at least 6 months. RESULTS: The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of FDG-PET images were 100%, 93.4%, 95.5%, 87.5%, and 100%, respectively. In contrast, the sensitivity, specificity, accuracy, PPV, and NPV of the MRI scans were 61.9%, 43.5%, 49.3%, 33.3%, and 70.0%, respectively. CONCLUSIONS: The results of the current study suggest that FDG-PET is much more effective than MRI in detecting residual/recurrent NPC.

Diffusion-weighted images in children with meningoencephalitis.

PURPOSE: The objective of the study was to evaluate the maps of apparent diffusion coefficients (ADCs) and diffusion-weighted (DW) images in demonstrating meningoencephalitic lesions in children. MATERIALS AND METHODS: Between May 1998 and May 2000, 18 infants and children (4.5-190 months old) suffering from meningoencephalitis were included in the study. The diagnoses were bacterial meningoencephalitis in 8 and aseptic or viral in 10 patients. All 18 patients had brain MRI examinations. In the axial plane, three pulse sequences were performed on all patients: (1) FSE T2W images; (2) fast FLAIR images; (3) single-shot echoplanar DW images were acquired. Another 18 patients from the control group also received DW image examination. ADCs were computed for all regions on each DW image. RESULTS: The absolute values of CNRs of lesions on T2W (7.27+/-5.51), FLAIR (5.56+/-5.03) and DW (13.36+/-16.64) images were significantly greater than those on ADC maps (0.42+/-0.30) in the study group of patients (P<.01). In addition, absolute CNRs on DW images were significantly greater than on T2W and FLAIR images (P<.01). However, lesions on ADC maps in the study group have significantly greater CNRs than in the control group (0.13+/-0.12) (P<.01). CNRs on initial DW images from patients with atrophy or swelling of meningoencephalitic lesions were significantly different from the CNRs of those patients without significant changes in meningoencephalitic lesions (P=.02<.05). CONCLUSION: The DW image is a sensitive tool for detecting meningoencephalitic lesions and is better than FSE T2W and fast FLAIR images in CNRs. Diffusion MR techniques provides new ways to possibly predict the outcome of intracranial infectious diseases in children.

Comparison of contrast-enhanced magnetization transfer imaging and contrast-enhanced fat saturation T1-weighted imaging in nasopharyngeal carcinoma.

OBJECTIVE: The objective of this study was to evaluate the efficacy of contrast-enhanced magnetization transfer (CEMT) imaging in the study of nasopharyngeal carcinoma (NPC). METHODS: The contrast-to-noise ratio (CNR) of CEMT images was compared with the CNR of contrast-enhanced fat-saturation (CEFS) T1-weighted images in locoregional tumors and adenopathies of 50 patients with pathologically proven NPC. RESULTS: The CEMT images showed higher CNRs than CEFS images of local nasopharyngeal regions. The mean CNRs of the precontrast T1-weighted, CEFS, and CEMT images were 4.9, 15.4, and 21.2, respectively. There was a statistically significant difference (p < 0.01) in the CNRs of CEFS and CEMT images. In considering images of nodal metastasis, the mean values in these three groups were 0.7, 16.8, and 19.7, respectively, with the difference (p < 0.05) between CEFS and CEMT being statistically significant. CONCLUSIONS: The CEMT image with a larger CNR is superior to the CEFS image in detecting locoregional NPC. CEMT can be useful in imaging patients with possible small tumors and local recurrences.