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1.  Pathological correlation with diffusion restriction on diffusion-weighted imaging in patients with pathological complete response after neoadjuvant chemoradiation therapy for locally advanced rectal cancer: preliminary results 
The British Journal of Radiology  2012;85(1017):e566-e572.
Objective
The objective of this study was to assess causative pathological factors associated with diffusion restriction on diffusion-weighted imaging (DWI) in patients who achieved pathological complete response (pCR) after treatment with neoadjuvant chemoradiation therapy (CRT) for locally advanced rectal cancer.
Methods
In total, 43 patients with locally advanced rectal cancer (≥T3 or lymph node positive) who underwent neoadjuvant CRT, subsequent surgery and ultimately achieved pCR were enrolled. All patients underwent pre- and post-CRT 3.0 T rectal MRI with DWI. Two radiologists blinded to pathological staging reviewed pre- and post-CRT 3.0 T rectal MRI for the presence of diffusion restriction in the corresponding tumour areas on post-CRT DWI, with a third radiologist arbitrating any disagreement. The consensus of these findings was then correlated with pathological data such as intramural mucin and the degree of proctitis and mural fibrosis seen on surgical specimen. Additionally, the pre-CRT tumour volume was measured to define the effect of this variable on the degree of radiation proctitis and fibrosis, as well as the presence of intramural mucin.
Results
Diffusion restriction occurred in 18 subjects (41.9%), while 25 subjects remained diffusion restriction-free (58.1%). The diffusion restriction group tended to have more severe proctitis and mural fibrosis when compared with non-diffusion restriction group (p<0.001). Intramural mucin was also more common in the diffusion restriction group (p=0.052). Higher pre-CRT tumour volumes were significantly predictive of the degree of proctitis (p=0.0247) and fibrosis (p=0.0445), but not the presence of intramural mucin (p=0.0944). Proctitis and mural fibrosis severity were also identified as independent pathological risk factors for diffusion restriction on multivariate analysis (p=0.0073 and 0.0011, respectively).
Conclusion
Both radiation-induced proctitis and fibrosis were significant and independent predictors of diffusion restriction in patients achieving pCR after treatment with neoadjuvant CRT for locally advanced rectal cancer, and pre-CRT tumour volume significantly affects both variables.
doi:10.1259/bjr/24557556
PMCID: PMC3487069  PMID: 22422387
2.  Small (≤2 cm) hepatocellular carcinoma in patients with chronic liver disease: comparison of gadoxetic acid-enhanced 3.0 T MRI and multiphasic 64-multirow detector CT 
The British Journal of Radiology  2012;85(1015):e314-e322.
Objectives
To compare the diagnostic performance of gadoxetic acid-enhanced MRI using 3.0 T with that of multiphasic 64-multirow detector CT (MDCT) for the detection of small (≤2 cm) hepatocellular carcinoma (HCC) in patients with chronic liver disease.
Methods
A total of 54 patients (44 men, 10 women; age range, 33–81 years) with 59 HCCs (≤2 cm in diameter) who underwent both multiphasic (arterial, portal venous, equilibrium) 64-MDCT and gadoxetic acid-enhanced 3.0 T MRI were enrolled in this study. Two observers independently and randomly reviewed the MR and CT images on a lesion-by-lesion basis. The diagnostic performance of these techniques for the detection of HCC was assessed by alternative free-response receiver operating characteristic (ROC) analysis, in addition to evaluating the sensitivity and positive predictive value.
Results
For each observer, the areas under the ROC curve were 0.874 and 0.863 for MRI, respectively, as opposed to 0.660 and 0.687 for CT, respectively. The differences between the two techniques were statistically significant for each observer (p<0.001). The sensitivities (89.8% and 86.4%) of MRI for both observers were significantly higher than those (57.6% and 61.0% for each observer, respectively) of MDCT. No significant difference was seen between the positive predictive values for the two techniques (p>0.05).
Conclusion
Gadoxetic acid-enhanced 3.0 T MRI shows a better diagnostic performance than that of 64-MDCT for the detection of small (≤2 cm) HCCs in patients with chronic liver disease.
doi:10.1259/bjr/27727228
PMCID: PMC3474077  PMID: 22167508
3.  Hounsfield units upon PET/CT are useful in evaluating metastatic regional lymph nodes in patients with oesophageal squamous cell carcinoma 
The British Journal of Radiology  2012;85(1013):606-612.
Objectives
This study evaluated the usefulness of measurements of X-ray attenuation (in Hounsfield units) obtained from unenhanced CT images for attenuation correction of the positron emission tomography (PET) data from PET/CT in the assessment of regional lymph node metastasis in oesophageal squamous cell carcinoma.
Methods
17 patients with oesophageal squamous cell carcinoma underwent surgery after evaluation with PET/CT. After the excised lymph nodes were reviewed, we compared the histopathology and PET/CT findings, and analysed the lymph node metastasis. When 18-F fludeoxyglucose (FDG) uptake in the lymph nodes was focally prominent in comparison with background mediastinal activity (regardless of lymph node size), the lymph nodes were considered to be positive for malignancy by PET/CT. The mean Hounsfield units of mediastinal lymph nodes showing abnormally increased FDG uptake in PET/CT was retrospectively evaluated using images from the unenhanced CT component of PET/CT. Receiver operating characteristic (ROC) curve analysis was applied to determine the optimal cut-off value of mean Hounsfield units for detecting individual lymph node metastases.
Results
For depiction of malignant nodal groups in each lymph node group, the sensitivity, specificity and accuracy of PET/CT based on increased FDG uptake were 58.8%, 74.5% and 70.8%, respectively. For patients with nodal groups that were positive for uptake by PET/CT, the mean attenuation in lymph nodes as measured by CT was 48±13 HU for malignant nodes and 75±18 HU for benign nodes. This difference was statistically significant (p<0.001). Using ROC curve analysis, we determined the cut-off as 71 HU. When we excluded lymph nodes with attenuation higher than 71 HU from the nodes determined as malignant by PET/CT, the specificity and accuracy for detecting metastatic lymph nodes improved to 90.9% and 83.3%, respectively.
Conclusions
When interpreting lymph node metastasis in oesophageal squamous cell carcinoma using PET/CT, the assumption that any lymph node with mean HU>71 is benign can improve diagnostic accuracy.
doi:10.1259/bjr/73516936
PMCID: PMC3479874  PMID: 21304006
4.  Value of diffusion-weighted imaging in the detection of viable tumour after neoadjuvant chemoradiation therapy in patients with locally advanced rectal cancer: comparison with T2 weighted and PET/CT imaging 
The British Journal of Radiology  2012;85(1013):577-586.
Objectives
To evaluate the added value of diffusion-weighted imaging (DWI) in combination with T2 weighted imaging (T2WI) compared with T2WI alone or positron emission tomography (PET)/CT for detecting viable tumour after neoadjuvant chemoradiation therapy (CRT) in patients with locally advanced rectal cancer.
Methods
50 consecutive patients with locally advanced rectal cancer (≥T3 or lymph node positive) who underwent neoadjuvant CRT and subsequent surgery were enrolled in this retrospective study. All patients underwent 3.0 T rectal MRI and PET/CT after completing CRT. For qualitative analysis, two radiologists independently reviewed T2WI alone and DWI with T2WI over a 1-month interval. One nuclear medicine physician reviewed PET/CT images using a five-point scale. Diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting viable tumour were assessed. For quantitative analysis, the apparent diffusion coefficients (ADCs) of the lesions were measured and compared between the viable tumour group and non-viable tumour groups.
Results
For detecting viable tumours, DWI with T2WI improved diagnostic accuracies (Reviewer 1 detected 90%; Reviewer 2, 86%) over T2WI alone (Reviewer 1 detected 76%, p=0.5; Reviewer 2, 64%, p=0.013) or PET/CT (48%, p<0.001). The sensitivity of DWI with T2WI (Reviewer 1 detected 98%; Reviewer 2, 91%) was significantly higher than those of T2WI alone (Reviewer 1 detected 77%; Reviewer 2, 64%) or PET-CT (43%, p<0.05). Only for Reviewer 2 was the NPV of DWI with T2WI (43%) significantly different from that of PET/CT (17%, p<0.05). The specificities and PPVs of DWI with T2WI were not improved over those of T2WI alone or of PET/CT (both p>0.05). The mean ADC of the viable tumour group (0.93×10−3 mm2 sc−1) was significantly lower than that of the non-viable tumour group (1.55×10−3 mm2 sc−1, p<0.0001).
Conclusion
Adding DWI to T2WI is helpful for detecting viable tumours after neoadjuvant CRT compared with T2WI alone or PET/CT in patients with locally advanced rectal cancer.
doi:10.1259/bjr/68424021
PMCID: PMC3479876  PMID: 21343320
5.  The value of dual-time-point 18F-FDG PET/CT for identifying axillary lymph node metastasis in breast cancer patients 
The British Journal of Radiology  2011;84(1003):593-599.
Objective
The sensitivity of 18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) for detecting axillary lymph node (ALN) metastases in breast cancer is reported to be low. Several studies have shown, however, that dual-time-point 18F-FDG PET imaging provides improved accuracy in the diagnosis of certain primary tumours when compared with single-scan imaging. The purpose of this study was to assess whether the use of dual-time-point 18F-FDG PET/CT scans could improve the diagnostic accuracy of ALN metastasis in breast cancer.
Method
The study included 171 breast cancer patients who underwent pre-operative 18F-FDG PET/CT scans at 2 time-points, the first at 1 h after radiotracer injection and the second 3 h after injection. Where 18F-FDG uptake was in the ALN perceptibly increased, the maximum standardised uptake values for both time-points (SUVmax1 and SUVmax2) and the retention index (RI) were calculated. Correlation between the PET/CT results and post-operative histological results was assessed.
Results
The performance of 1 h and 3 h PET/CT scans was equal, with sensitivity 60.3% and specificity 84.7%, in detecting ALN metastasis. Out of 171 patients, 60 had ALNs with increased 18F-FDG uptake on 1 h or 3 h images. There was no significant difference in RI between the metastatic ALN-positive group and the node-negative group. The area under the receiver operating characteristic (ROC) curve for SUVmax1 was 0.90 (p<0.001) and 0.87 for SUVmax2 (p<0.001).
Conclusion
Dual time-point imaging did not improve the overall performance of 18F-FDG PET/CT in detecting ALN metastasis in breast cancer patients.
doi:10.1259/bjr/56324742
PMCID: PMC3473484  PMID: 21081574
6.  Uterine cavernous haemangioma in a post-menopausal woman: CT and MRI findings mimicking uterine myoma with degeneration 
The British Journal of Radiology  2011;84(1000):e68-e71.
Cavernous haemangioma is a very rare vascular malformation of the uterus. We describe the CT and MRI findings of a cavernous haemangioma in an 81-year-old female with recurrent menorrhagia. CT showed a well-marginated mass with multifocal calcifications and extensive haemorrhage, as well as necrosis in the anterior wall of the uterus. MRI revealed heterogeneous low- to high-signal intensities of the mass on T1 and T2 weighted images as well as portions with poor enhancement of the mass on contrast-enhanced T1 weighted images. Although rare, cavernous haemangioma should be included in the differential diagnosis of a calcified haemorrhagic necrotic uterine mass in post-menopausal women.
doi:10.1259/bjr/56484373
PMCID: PMC3473473  PMID: 21415295
7.  Atypical radiological features of a leiomyosarcoma that arose from the ovarian vein and mimicked a vascular tumour 
The British Journal of Radiology  2010;83(989):e095-e097.
Leiomyosarcomas of the ovarian vein are extremely rare tumours. Most tumours are hypervascular and typically have a large avascular centre of necrosis. We experienced a case of a retroperitoneal leiomyosarcoma that arose from the ovarian vein with marked vascular proliferation and dilatation within the tumour. To the best of our knowledge, this is the first case report of a retroperitoneal leiomyosarcoma with an atypical vascular structure in the clinical literature.
doi:10.1259/bjr/50917539
PMCID: PMC3473564  PMID: 20418463

Results 1-7 (7)