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1.  Liver T1ρ MRI measurement in healthy human subjects at 3 T: a preliminary study with a two-dimensional fast-field echo sequence 
The British Journal of Radiology  2012;85(1017):e590-e595.
The aim of this study was to explore the technical feasibility of T1ρ MRI for the liver, and to determine the normal range of liver T1ρ in healthy subjects at clinical 3 T.
There were 15 healthy volunteers. Three representative axial slices were selected to cut through the upper, middle and lower liver. A rotary echo spin-lock pulse was implemented in a two-dimensional fast-field echo sequence. Spin-lock frequency was 500 Hz, and the spin-lock times of 1, 10, 20, 30, 40 and 50 ms were used for T1ρ mapping. The images were acquired slice by slice during breath-holding. Regions of interest (ROIs; n=5) were manually placed on each slice of the liver parenchyma region, excluding artefacts and vessels. The mean value of these ROIs (n=15) was regarded as the liver T1ρ value for the subject. Six subjects were scanned once at fasting status; six subjects were scanned once 2 h post meal; three subjects were scanned twice at fasting status; and seven subjects were scanned twice 2 h post meal.
When two readers measured the same 10 data sets, the interreader reproducibility (ICC: intraclass correlation coefficient) was 0.955. With the 10 subjects scanned twice, the ICC for scan–rescan reproducibility was 0.764. There was no significant difference for the liver T1ρ value at the fasting status (43.08±1.41 ms) and post-meal status (42.97±2.38 ms, p=0.867). Pooling together all the 32 scans in this study, the normal liver T1ρ value ranged from 38.6 to 48.3 ms (mean 43.0 ms, median 42.6 ms).
It is feasible to obtain consistent liver T1ρ measurement for human subjects at 3 T.
PMCID: PMC3487072  PMID: 22422392
2.  Compromised perfusion in femoral head in normal rats: distinctive perfusion MRI evidence of contrast washout delay 
The British Journal of Radiology  2012;85(1016):e436-e441.
The femoral head is prone to osteonecrosis. This study investigated dynamic contrast-enhanced (DCE) MRI contrast washout features of the femoral head and compared the data with data from other bony compartments in normal rats.
7-month-old Wistar rats were used. DCE MRI of the right hip (n=18), right knee (n=12) and lumbar spine (n=10) was performed after an intravenous bolus injection of Gd-DOTA (0.3 mmol kg–1). Temporal resolution was 0.6 s for hip and spine, and 0.3 s for knee. The total scan duration was 8 min for hip and spine, and 4.5 min for knee. The regions of interest for enhancement measurement included femoral head, proximal femoral diaphysis, distal femoral diaphysis and epiphysis, proximal tibial epiphysis and diaphysis, and lumbar vertebrae L1–5.
Femoral head showed no enhancement signal decay during the DCE MRI period, while all other bony compartments showed a contrast washin phase followed by a contrast washout phase. In the knee joint, the contrast washout of the proximal tibia diaphysis was slower that of other bony compartments of the knee.
Based on the evidence of delayed contrast washout, this study showed that blood perfusion in the femoral head could be compromised in normal rats.
PMCID: PMC3587097  PMID: 22167506
3.  Facial wrigglies: live extralymphatic filarial infestation in subcutaneous tissues of the head and neck 
The British Journal of Radiology  2011;84(1002):e126-e129.
We report a rare case of a 32-year-old male with live extralymphatic filarial infestation presenting as a facial subcutaneous soft-tissue swelling. To the best of our knowledge these imaging findings have not been previously reported in the head and neck region in the existing English language literature. Real-time high-resolution ultrasonography revealed a solitary well-defined subcutaneous cystic lesion over the right zygomatic arch. It showed multiple linear, echogenic, undulating structures exhibiting a persistent twirling motion during the examination. This typical ultrasonographic appearance was consistent with the filarial dance sign (FDS) of live adult filarial worms. Subsequent MRI confirmed the cystic and solitary nature of the lesion. Complete excision of the cyst was performed, which revealed intracystic straw-coloured fluid and multiple white-coloured adult worms within the lesion. Histopathological examination confirmed multiple adult filarial worms with surrounding reactive inflammatory changes. In an endemic region, identification of the FDS in any normal anatomical structure or abnormal swelling, however remote or unusual the location within the body, should strongly suggest the diagnosis of live active filarial infestation. In view of the increasing migratory trends in the global population, it is imperative for radiologists in all countries to be aware of the typical imaging findings of this disease to arrive at the correct diagnosis.
PMCID: PMC3473634  PMID: 21606067
4.  Does primary tumour volumetry performed early in the course of definitive concomitant chemoradiotherapy for head and neck squamous cell carcinoma improve prediction of primary site outcome? 
The British Journal of Radiology  2010;83(995):964-970.
Although previous studies have documented correlations between pre-treatment or post-treatment primary tumour volumes and local outcome following definitive concomitant chemoradiotherapy (CCRT) in head and neck squamous cell carcinoma (HNSCC), no study has included and compared tumour volumes during CCRT.
We reviewed the MRIs of 69 HNSCC patients treated with a 6 weeks course of CCRT and who underwent successful MRI pre-treatment (n = 69), 2 weeks intra-treatment (n = 48) and 6 weeks post-treatment (n = 61). Primary tumour volumes on MRI at the three time points were calculated and compared for their predictive value for primary site outcome. Volume thresholds optimised to predict failure with the highest accuracy and positive predictive value (PPV) were calculated. The mean pre-treatment volume was 24.6 cm3 (range, 1.1–187.9 cm3) and the mean follow-up interval was 41 months (range, 12–100 months). 23 primary tumours failed treatment (33%). Volumes before, during and after CCRT were positively associated with local failure (p = 0.015, p = 0.009, p<0.0001). Volume reductions during and after CCRT were negatively associated with local failure (p = 0.021, p = 0.001). Pre-treatment and intra-treatment volume thresholds achieved the highest accuracy and produced intermediate PPVs (51–64%) for predicting local failure. Optimised intra-treatment thresholds did not identify any more treatment failures than the pre-treatment thresholds. By comparison, a 6 weeks post-treatment volume reduction (<35%) achieved 100% PPV for failure, albeit with 26% sensitivity.
In conclusion, primary tumour volumetry performed early in CCRT provides minimal additional information compared with pre-treatment volumetry, with respect to predicting post-treatment local failures. Therefore, volumetry during CCRT is unlikely to be useful for guiding individual response-based therapeutic modifications.
PMCID: PMC3473721  PMID: 20965907
5.  Can diffusion-weighted imaging distinguish between normal and squamous cell carcinoma of the palatine tonsil? 
The British Journal of Radiology  2010;83(993):753-758.
The utility of diffusion-weighted imaging (DWI) in the detection of squamous cell carcinoma (SCC) of the tonsils has not been previously investigated. This preliminary study compared DWI of apparent SCC tonsillar tumours with normal tonsils. DWI of the tonsils was performed in 10 patients with newly diagnosed tonsil SCC that was evident on conventional MRI and in 17 patients undergoing cranial MRI for other indications. Regions of interest (ROI) were drawn around each identifiable tonsil on the apparent diffusion coefficient (ADC) map and the mean ADC value for each tonsil was calculated. ADC values for normal and SCC tonsils were compared using the Mann–Whitney U-test. The median ADC and range (×10−3 mm2 s–1) were found to be 0.814 and 0.548–1.312, respectively, for normal tonsils compared with 0.933 and 0.789–1.175, respectively, for SCC tonsils. ADC values were significantly higher for SCC tonsils than for normal tonsils (p = 0.009). No SCC tonsil had an ADC less than 0.82×10−3 mm2 s–1 compared with 58% of normal tonsils. We conclude that there is a difference in the ADC between normal tonsils and SCC tonsils where the cancer is apparent on conventional MRI. These results are promising, although further studies are now required to determine whether DWI can be used to identify or exclude smaller foci of SCC within tonsils where the cancer is not evident on conventional MRI.
PMCID: PMC3473413  PMID: 20647507

Results 1-5 (5)