Imaging characteristics of nasopharyngeal carcinoma for predicting distant metastasis.

AIM: To determine the imaging characteristics of nasopharyngeal carcinoma (NPC) that may be associated with increased risk of distant metastasis. MATERIALS AND METHODS: A total 164 patients with NPC were reviewed retrospectively. Patients were divided into the metastatic group (n=110) or the non-metastatic group (n=54). Non-metastatic was defined as no evidence of distant metastasis during at least 5 years of follow-up. Pretreatment images of the primary tumour and nodal involvement were analysed. Statistical analyses were performed to identify the factors that may predict distant metastasis. RESULTS: The statistically significant sites of tumour extension in the metastatic group included: skull base bone (p<0.001), cervical spine (C-spine; p=0.012), parapharyngeal space (p=0.003), pterygopalatine fossae (PPF; p=0.004), prevertebral space (p<0.001), masticator space (p=0.006), carotid space (p=0.001), and intracranial extension (p=0.004). Statistically significant nodal involvement included bilateral involvement (p=0.04), size 3-6 cm (p=0.011), >10 pathological nodes (p<0.001), level IB (p=0.013), IIB (p=0.011), III (p=0.001), IV (p<0.001), VB (p=0.001), and supraclavicular (p=0.003) and intraparotid nodes (p=0.004). The mean number of significant involvement factors was significantly higher in the metastatic group (3.46±2.24 tumour extension sites and 5.04±2.51 nodal involvement factors) than in the non-metastatic group (p<0.001). CONCLUSION: NPC patients with local extension at more than three sites and with more than five nodal involvement factors should be screened for distant metastasis.

A novel stop codon mutation in exon 1 (558C>A) of the UGT1A1 gene in a Thai neonate with Crigler-Najjar syndrome type I.

Human uridine 5'-diphosphate-glucuronosyltransferases play a critical role in detoxification by conjugating bilirubin with glucoronic acid. Impaired or reduced enzymatic activity causes a spectrum of clinical disorders such as Crigler-Najjar syndrome type I (CN1), Crigler-Najjar syndrome type II, and Gilbert's syndrome. CN1 is a severe form of unconjugated hyperbilirubinemia caused by homozygous or compound heterozygous mutations in the gene for uridine 5'-diphosphate glucuronosyltransferase 1 family, polypeptide A1 (UGT1A1), resulting in complete loss of enzyme function. Here, we report a novel homozygous mutation of UGT1A1 in a female Thai infant who was diagnosed with CN1, and her parents were found to be heterozygous carriers. The patient was homozygous for the c.558C>A mutation, which resulted in a premature stop codon in exon 1. Her asymptomatic parents were carriers of the nonsense c.558C>A mutation. Our result suggests an important role for homozygous c.558C>A mutations in the UGT1A1 gene in the development of severe unconjugated hyperbilirubinemia.

Imaging characteristics of oligodendrogliomas that predict grade.

BACKGROUND AND PURPOSE: Oligodendrogliomas are tumors that have variable WHO grades depending on anaplasia and astrocytic components and their treatment may differ accordingly. Our aim was to retrospectively evaluate imaging features of oligodendrogliomas that predict tumor grade. MATERIALS AND METHODS: The imaging studies of 75 patients with oligodendrogliomas were retrospectively reviewed and compared with the histologic grade. The presence and degree of enhancement and calcification were evaluated subjectively. rCBV and ADC maps were measured. Logistic linear regression models were used to determine the relationship between imaging factors and tumor grade. RESULTS: Thirty of 75 (40%) tumors enhanced, including 9 of 46 (19.6%) grade II and 21 of 29 (72.4%) grade III tumors (P < .001). Grade III tumors showed lower ADC values compared with grade II tumors (odds ratio of a tumor being grade III rather than grade II = 0.07; 95% CI, 0.02-0.25; P = .001). An optimal ADC cutoff of 925 10(-6) mm(2)/s was established, which yielded a specificity of 89.1%, sensitivity of 62.1%, and accuracy of 78.7%. There was no statistically significant association between tumor grade and the presence of calcification and perfusion values. Multivariable prediction rules were applied for ADC < 925 10(-6) mm(2)/s, the presence of enhancement, and the presence of calcification. If either ADC < 925 10(-6) mm(2)/s or enhancement was present, it yielded 93.1% sensitivity, 73.9% specificity, and 81.3% accuracy. The most accurate (82.2%) predictive rule was seen when either ADC < 925 10(-6) mm(2)/s or enhancement and calcification were present. CONCLUSIONS: Models based on contrast enhancement, calcification, and ADC values can assist in predicting the grade of oligodendrogliomas and help direct biopsy sites, raise suspicion of sampling error, and predict prognosis.

Detection of intratumoral calcification in oligodendrogliomas by susceptibility-weighted MR imaging.

BACKGROUND AND PURPOSE: SWI is a unique pulse sequence sensitive to both hemorrhage and calcification. Our aim was to retrospectively assess the ability of SWI to detect intratumoral calcification in ODs compared with conventional MR imaging. MATERIALS AND METHODS: Using CT as criterion standard, the MR imaging findings from 71 patients (33 males, 38 females; mean age, 42.5 years) with pathologically proved OD were retrospectively evaluated. We classified the MR imaging data into SWI data (MRSWI) and traditional pulse sequences (MRnoSWI). The sensitivity and specificity of the MRnoSWI (n = 71) were compared with that of the MRSWI (n = 13) independently and also for matched-paired data (n = 13). The Fisher exact test was applied to the matched-pair data for statistical evaluation. RESULTS: For paired data of MRSWI and MRnoSWI (n = 13), there was significantly increased sensitivity of MRSWI (86%) for the detection of intratumoral calcification in OD compared with the MRnoSWI (14.3%) (P = .015, Fisher exact test) by using CT as the criterion standard. The overall accuracy of MRSWI for the paired data was also significantly greater (P = .048). The specificities were not significantly different (P = .773). The sensitivity of MRSWI (n = 13) was 86%, and for MRnoSWI (n = 71), it was 33.3%. Specificity of MRSWI was 83%, and for MRnoSWI, it was 95%. CONCLUSIONS: SWI is better able to detect calcification in ODs than conventional MR imaging pulse sequences.

Distinguishing between germinomas and pineal cell tumors on MR imaging.

BACKGROUND AND PURPOSE: Tumors of pineal cell origin have different prognosis and treatment than those of germ cell origin. The recent literature suggests that these tumors often look alike. Our study aimed to differentiate between pineal cell tumor and germinoma based on ADC values, the homogeneity of the mass, and MR imaging characteristics. MATERIALS AND METHODS: We enrolled 20 patients who had pretreatment MR imaging scans with histologic verification of tumors of pineal cell origin and germinomas. The tumors were measured for the ADC values and for homogeneity by the coefficient of variation of ADC values, and T1WI and T2WI signal intensity values. RESULTS: The 20 subjects (8 females and 12 males) ranged in age from 1.5-64.9 years, with a mean age of 23.9 years (SD 17.7 years). The mean age of those with germinomas was 13.7 years (SD 3.8 years), less than the mean of 29.4 years for those with pineal cell tumors (SD 19.9 years; P = .016). These 2 groups showed no significant difference in coefficients of variation on T1WI, T2WI, and ADC images. However, germinomas showed statistically significant higher ADC values (mean 1590.69 ± 532.96 × 10(-6) mm(2)/s) than pineal cell tumors (mean 883.58 ± 317.48 × 10(-6) mm(2)/s; P = .02). An accuracy of 89.5%, sensitivity of 83.3%, specificity of 92.3%, PPV of 83.3%, and NPV of 92.3% were yielded for an ADC threshold of 1250.00 × 10(-6) mm(2)/s. CONCLUSIONS: Germinomas showed higher ADC values than the pineal cell tumors (P = .02), and the patients were younger. Otherwise, there were no definitive imaging characteristics that distinguished pineal cell tumors from germinomas.