CT perfusion imaging in response assessment of pulmonary metastases undergoing stereotactic ablative radiotherapy.

INTRODUCTION: Stereotactic ablative body radiotherapy (SABR) is an emerging treatment technique for pulmonary metastases in which conventional Response Evaluation Criteria in Solid Tumours (RECIST) may be inadequate. This study aims to assess the utility of CT perfusion imaging in response assessment of pulmonary metastases after SABR. METHODS: In this ethics board-approved prospective study, 11 patients underwent a 26-Gy single fraction of SABR to pulmonary metastases. CT perfusion imaging occurred prior to and at 14 and 70 days post-SABR. Blood flow (mL/100 mL/min), blood volume (mL/100 mL), time to peak (seconds) and surface permeability (mL/100 mL/min), perfusion parameters of pulmonary metastases undergoing SABR, were independently assessed by two radiologists. Inter-observer variability was analysed. CT perfusion results were analysed for early response assessment comparing day 14 with baseline scans and for late response by comparing day 70 with baseline scans. The largest diameter of the pulmonary metastases undergoing SABR was recorded. RESULTS: Ten patients completed all three scans and one patient had baseline and early response assessment CT perfusion scans only. There was strong level of inter-observer agreement of CT perfusion interpretation with a median intraclass coefficient of 0.87 (range 0.20-0.98). Changes in all four perfusion parameters and tumour sizes were not statistically significant. CONCLUSION: CT perfusion imaging of pulmonary metastases is a highly reproducible imaging technique that may provide additional response assessment information above that of conventional RECIST, and it warrants further study in a larger cohort of patients undergoing SABR.

Clinical 24 month experience of the first MRgFUS unit for treatment of uterine fibroids in Australia.

AIM: To describe and evaluate treatment of uterine fibroids using Magnetic Resonance Guided Focused Ultrasound (MRgFUS) during its first 24 months of use at The Royal Women's Hospital Melbourne. METHODS: One hundred Victorian women were treated with MRgFUS using the ExAblate 2000 system. Treatment outcomes based on fibroid volume shrinkage measured at 4 and 12 months post-treatment and symptom severity score assessment (Symptom Severity Score Quality of Life - SSS-QOL) pre- and post- (4-6 weeks, 4, 6 and 12 months) treatment. RESULTS: Mean non-perfused volume of the treated fibroids were 67% ± 25% (n = 100) immediately post-treatment. At 4 months post-treatment, the treated fibroids demonstrated an average volume reduction of 29% ± 32% (n = 74) and at 12 months 38% ± 45% (n = 32). Mean symptom severity scores (SSS-QOL) improved by 51% from 59 ± 21 (n = 97) at baseline to 29 ± 17 (n = 36) by 12 months. CONCLUSION: From our experience, we believe there is a role for MRgFUS in the treatment of uterine fibroids in selected women.

Comparison of readers' detection of right-sided and left-sided breast cancers and microcalcifications.

INTRODUCTION: Aim of this study was to determine if there is a statistically and clinically significant difference in diagnostic performance (cancer diagnosis) and perceptual performance (microcalcification detection) when detecting left-sided or right-sided breast cancers and microcalcifications. METHODS: Eight radiologist readers (8-20 years experience in radiology, five current BreastScreen readers) read a set of 100 digital mammograms (23/100 had proven malignancies and 52/100 had confirmed microcalcifications) for three reads (random case order in each read). The same mammograms were presented on two reads, serving as the baseline reads. The data from these reads were used to calculate intra-observer variability (presented in an earlier study). The experimental read consisted of left-right mirror images of the original mammograms. In each read, the radiologists were requested to 'clear' or 'call-back' cases and to indicate if any microcalcifications (benign and malignant) were present on the mammograms. Reading conditions were standardised. RESULTS: Comparison of intra-reader performance difference for left-sided versus right-sided breast cancers and microcalcifications with intra-observer variability for breast cancer diagnosis and microcalcification detection, respectively, revealed no clinically significant difference between left-sided and right-sided detections. Per-case analysis showed more left-sided breast cancers and microcalcifications correctly detected. This left-right difference in detection did not reach statistical significance, P-value of 0.28 for cancer diagnosis and 0.74 for microcalcification detection. CONCLUSION: There is no statistically or clinically significant difference between left-sided and right-sided breast cancer diagnosis and microcalcification detection in a group of experienced radiologists. Individual reading patterns do not affect detection rates of left-sided and right-sided cancers and microcalcifications.

Intrareader variability in mammographic diagnostic and perceptual performance amongst experienced radiologists in Australia.

INTRODUCTION: The purpose of this study was, for a group of experienced radiologists, to identify the magnitude of and statistical significance of intrareader variability in mammographic diagnostic performance or cancer diagnosis and mammographic perceptual performance or microcalcification detection. METHODS: Eight radiologist readers (8-30 years experience in radiology, five current BreastScreen readers) read a set of 100 digital mammograms on two separate reads with random case orders. Twenty-three of the 100 had proven malignancies, and 52 of the 100 had confirmed microcalcifications. The same mammograms were presented for both reads. The radiologists were requested to clear or call back cases and to indicate if any benign and malignant microcalcifications were present on the mammograms. Reading conditions were standardised. RESULTS: Intrareader variability in accuracy was demonstrated to be between 0% and 6% for the diagnostic task of breast cancer diagnosis and between 0% and 16% for the perceptual task of microcalcification detection. Intrareader agreement in the group of readers was high; between 75% and 93% (κ=0.36-0.72) for cancer diagnosis and between 77.5% and 93% (κ=0.17-0.77) for microcalcification detection. There was no correlation between reader's experience in radiology or being a BreastScreen reader and level of intrareader variability in cancer diagnosis and microcalcification detection. CONCLUSION: There exists intrareader variability in diagnostic and perceptual performance. Despite this variability, intrareader agreement remains high.

Comparison of 3MP medical-grade to 1MP office-grade LCD monitors in mammographic diagnostic and perceptual performance.

INTRODUCTION: Picture archiving and communication systems images designed to be viewed on high-resolution medical-grade monitors are routinely viewed on office-grade monitors on the wards or at home. This study aimed to determine whether a statistically significant difference in diagnostic (cancer detection) and perceptual (microcalcification detection) performance exists between 3MP grade and 1MP office-grade monitors. METHODS: 3MP Dome medical-grade liquid crystal display (LCD) monitors (Planar, Beaverton, OR, USA) were compared to 1MP Dell office-grade LCD monitors (Dell Inc, Round Rock, TX, USA). Eight radiologists (reader experience 8-30 years) read the same set of 100 mammograms (23/100 with proven cancers and 52/100 with microcalcifications) presented in random order on three occasions separated by two time intervals of 12 weeks. Reads 1 and 3 utilised 3MP monitors and formed the baseline read. Read 2 utilised 1MP monitors and constituted the experimental read. Reading conditions were standardised. Readers were aware of which monitors they were using. Multivariate logistic regression analysis (to account for reader variability and monitor impact) was performed to assess for statistical significance. RESULTS: At α = 5%, confidence intervals analysis comparing the measured parameters between 1MP to 3MP monitors demonstrated no statistically significant difference in diagnostic and perceptual performance for the reader group. In cancer detection (the diagnostic task), reader accuracy remained high irrespective of monitor type. Regression analysis comparing performance with 1MP against 3MP monitors found P values of 0.693 and 0.324 for diagnostic and perceptual performance, respectively. CONCLUSION: There were no statistically and clinically significant differences between 3MP and 1MP monitors in mammographic diagnostic and perceptual performance. Comparable performance may be due to compensatory behaviour by readers.

Clinical experience of the first digital mammographic unit in Australia in its first year of use.

In April 2004, Melbourne's Peter MacCallum Cancer Centre, Australia's only stand-alone dedicated cancer hospital, became the first Australian site to offer digital mammography (DM). In the first year of DM operation, 1208 mammograms were performed on 1157 women; 17 new cases of invasive carcinoma and six new cases of ductal carcinoma-in-situ (DCIS) were detected; and 30 hook-wire needle localisations were conducted in 29 patients. We developed a unit policy to manage indeterminate microcalcifications newly demonstrated on DM that were not previously detected by conventional screen-film mammography (CM): those believed to have malignant morphology were recommended for biopsy, and those without were recommended for 6-month DM follow-up to confirm microcalcification stability. DM detected 56 new stand-alone microcalcifications (18 suspicious and 38 indeterminate). Tissue diagnosis of 12 suspicious microcalcifications yielded four cases of DCIS and one of atypical ductal hyperplasia. Of the indeterminate microcalcifications, 35 have demonstrated stability at DM follow-up to date, over a mean period of 23.6 months. From our experience, we believe DM's superior demonstration ability uncovered microcalcifications previously undetected by CM, rather than microcalcification progression. We suggest that routine review with DM, rather than biopsy, is appropriate management when new indeterminate microcalcifications without malignant characteristics are identified by DM.