Diffusion-weighted imaging in gynaecological malignancy

Diffusion weighted imaging (DWI) has become an essential part of the gynaecological magnetic resonance imaging (MRI) protocol. DWI is used as an adjunct to conventional MRI sequences and has been shown to improve reporting accuracy in the imaging of gynaecological malignancy. In this review, we discuss the role of DWI in the diagnosis, staging, and assessment of treatment response of endometrial, cervical, and ovarian cancer. We also review the role of DWI in the assessment of the sonographically indeterminate ovarian lesion. Further, we highlight potential pitfalls that can beset the accurate interpretation of DWI in patients with gynaecological malignancy.

Incidental breast lesions detected on CT: what is their significance?

An increasing number of breast lesions are being detected incidentally on CT. The aim of this study was to investigate the rate of referrals to the breast unit for assessment of lesions identified on CT and the resulting yield of previously undiagnosed breast malignancies from this pathway. A retrospective review was undertaken of CT examinations conducted over a period of 14 years. All patients (with no previous history of breast cancer) whose report contained the keyword "breast" and who were referred to a specialist breast unit for assessment were reviewed. CT lesion morphology and enhancement pattern were identified and compared with the final diagnostic outcome. 70 patients were identified by retrospective analysis, yielding 78 incidental breast lesions, of which 22 (28.2%) were malignant (category B5). This gave a positive predictive value (PPV) for malignancy of 28.2%. The best morphological predictor of malignancy was spiculation (PPV, 76%) and irregularity (PPV, 58%), whereas calcification patterns (PPV, 36%) were diagnostically unhelpful. Malignant lesions were likely to be larger (mean, 28.5 mm) than benign lesions (mean, 20.2 mm; p<0.05). In conclusion, 30% of incidental breast lesions in this large series of patients proved to be unsuspected breast cancers, particularly irregular spiculated masses. Referral for formal triple assessment of CT-diagnosed breast lesions is worthwhile, and careful examination of the breast should be a routine part of CT examinations.

RECIST and Choi criteria for response assessment (RA) in patients with inoperable and metastatic gastrointestinal stromal tumours (GISTs) on imatinib mesylate. Cambridge GIST study group experience

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Background: Imatinib Mesylate (IM) induces an overall response rate of 84% in patients (pts) with metastatic GISTs. Standard RA is by RECIST criteria. This may underestimate the true benefit of IM in such pts. Choi et al observed ↓ in size (10%) and or density (D) (15%) correlated well with disease specific survival. We report our experience using both RECIST and Choi criteria for RA in GIST pts on IM. Methods: Between 2003 and 06, 24 pts with metastatic or inoperable GISTs were treated with IM. 50 lesions (Liver 20, Omentum 21, Primary 9) were identified at presentation on contrast CT (Siemens multi slice CT, IV Niopam, GE PACS system). 3 monthly CT was used for RA until tumour progression (PD) or death. Parameters recorded were: 1.Largest dimension 2. Lesion density (Mean Hounsfield units, HFU) 3.New lesions 4.Any new features. RECIST and Choi criteria were both applied for RA. Results: N=50. At 3 months (m) only 16% of the lesions achieved partial response (PR) by RECIST and 24% increased in size by a mean of 22.5% (Range 3–150%). RA as measured by Choi criteria revealed 88% of lesions had either a 10% ↓ in size or a 15% ↓ in D at 3 m. Mean ↓ in D was 29% (95% CI 24.6–33.4). At 18 m 50% of the lesions achieved PR and 20% had PD by RECIST criteria, and with Choi criteria 68% RR was recorded. Calcification, haemorrhage and perforation within the lesions spuriously altered the mean D value in 15% of the lesions which made assessment by Choi criteria difficult. In 5 pts new hepatic cystic lesions (range 2–22) appeared with a mean D of 16 HF. None were detected in extra-hepatic sites. 4 pts showed new calcifications within lesions 3–18 m on IM. Enhancing nodules within lesions were seen in 4 pts predating clinical PD by 6–18 m. Conclusions: Choi criteria were found to be reproducible in our pts. RRs at 3 months using Choi criteria (88%) were far greater than by RECIST criteria (16%). RRs were more similar at 18 m (68% Choi vs 50% RECIST).Using density for RA can become unreliable in the presence of perforation, calcification and haemorrhage. These criteria should be evaluated by a radiologist experienced in assessing the response to IM in GISTs with awareness of their limitations.

No significant financial relationships to disclose.