The impact of imaging modality (CT vs MRI) and patient position (supine vs prone) on tangential whole breast radiation therapy planning.

PURPOSE: The purpose of this study was to evaluate the impact of magnetic resonance imaging (MRI) versus computed tomography (CT)-derived planning target volumes (PTVs), in both supine and prone positions, for whole breast (WB) radiation therapy. METHODS AND MATERIALS: Four WB radiation therapy plans were generated for 28 patients in which PTVs were generated based on CT or MRI data alone in both supine and prone positions. A 6-MV tangential intensity modulated radiation therapy technique was used, with plans designated as ideal, acceptable, or noncompliant. Dose metrics for PTVs and organs at risk were compared to analyze any differences based on imaging modality (CT vs MRI) or patient position (supine vs prone). RESULTS: With respect to imaging modality 2/11 whole breast planning target volume (WB_PTV) dose metrics (percentage of PTV receiving 90% and 110% of prescribed dose) displayed statistically significant differences; however, these differences did not alter the average plan compliance rank. With respect to patient positioning, the odds of having an ideal plan versus a noncompliant plan were higher for the supine position compared with the prone position (P = .026). The minimum distance between the seroma cavity planning target volume (SC_PTV) and the chest wall was increased with prone positioning (P < .001, supine and prone values 1.1 mm and 8.7 mm, respectively). Heart volume was greater in the supine position (P = .005). Heart doses were lower in the supine position than prone (P < .01, mean doses 3.4 ± 1.55 Gy vs 4.4 ± 1.13 Gy for supine vs prone, respectively). Mean lung doses met ideal dose constraints in both positions, but were best spared in the prone position. The contralateral breast maximum dose to 1cc (D1cc) showed significantly lower doses in the supine position (P < .001, 4.64 Gy vs 9.51 Gy). CONCLUSIONS: Planning with PTVs generated from MRI data showed no clinically significant differences from planning with PTVs generated from CT with respect to PTV and doses to organs at risk. Prone positioning within this study reduced mean lung dose and whole heart volumes but increased mean heart and contralateral breast doses compared with supine.

Comparison of Magnetic Resonance Imaging and Computed Tomography for Breast Target Volume Delineation in Prone and Supine Positions.

PURPOSE: To determine whether T2-weighted MRI improves seroma cavity (SC) and whole breast (WB) interobserver conformity for radiation therapy purposes, compared with the gold standard of CT, both in the prone and supine positions. METHODS AND MATERIALS: Eleven observers (2 radiologists and 9 radiation oncologists) delineated SC and WB clinical target volumes (CTVs) on T2-weighted MRI and CT supine and prone scans (4 scans per patient) for 33 patient datasets. Individual observer's volumes were compared using the Dice similarity coefficient, volume overlap index, center of mass shift, and Hausdorff distances. An average cavity visualization score was also determined. RESULTS: Imaging modality did not affect interobserver variation for WB CTVs. Prone WB CTVs were larger in volume and more conformal than supine CTVs (on both MRI and CT). Seroma cavity volumes were larger on CT than on MRI. Seroma cavity volumes proved to be comparable in interobserver conformity in both modalities (volume overlap index of 0.57 (95% Confidence Interval (CI) 0.54-0.60) for CT supine and 0.52 (95% CI 0.48-0.56) for MRI supine, 0.56 (95% CI 0.53-0.59) for CT prone and 0.55 (95% CI 0.51-0.59) for MRI prone); however, after registering modalities together the intermodality variation (Dice similarity coefficient of 0.41 (95% CI 0.36-0.46) for supine and 0.38 (0.34-0.42) for prone) was larger than the interobserver variability for SC, despite the location typically remaining constant. CONCLUSIONS: Magnetic resonance imaging interobserver variation was comparable to CT for the WB CTV and SC delineation, in both prone and supine positions. Although the cavity visualization score and interobserver concordance was not significantly higher for MRI than for CT, the SCs were smaller on MRI, potentially owing to clearer SC definition, especially on T2-weighted MR images.

A comparison between radiation therapists and medical specialists in the use of kilovoltage cone-beam computed tomography scans for potential lung cancer radiotherapy target verification and adaptation.

Target volume matching using cone-beam computed tomography (CBCT) is the preferred treatment verification method for lung cancer in many centers. However, radiation therapists (RTs) are trained in bony matching and not soft tissue matching. The purpose of this study was to determine whether RTs were equivalent to radiation oncologists (ROs) and radiologists (RDs) in alignment of the treatment CBCT with the gross tumor volume (GTV) defined at planning and in delineating the GTV on the treatment CBCT, as may be necessary for adaptive radiotherapy. In this study, 10 RTs, 1 RO, and 1 RD performed a manual tumor alignment and correction of the planning GTV to a treatment CBCT to generate an isocenter correction distance for 15 patient data sets. Participants also contoured the GTV on the same data sets. The isocenter correction distance and the contoured GTVs from the RTs were compared with the RD and RO. The mean difference in isocenter correction distances was 0.40cm between the RO and RD, 0.51cm between the RTs, and RO and 0.42cm between the RTs and RD. The 95% CIs were smaller than the equivalence limit of 0.5cm, indicating that the RTs were equivalent to the RO and RD. For GTV delineation comparisons, the RTs were not found to be equivalent to the RD or RO. The alignment of the planning defined GTV and treatment CBCT using soft tissue matching by the RTs has been shown to be equivalent to those by the RO and RD. However, tumor delineation by the RTs on the treatment CBCT was not equivalent to that of the RO and RD. Thus, it may be appropriate for RTs to undertake soft tissue alignment based on CBCT; however, further investigation may be necessary before RTs undertake delineation for adaptive radiotherapy purposes.

Effective notification of important non-urgent radiology results: a qualitative study of challenges and potential solutions.

INTRODUCTION: We report on the implementation of a Radiology Notification System (RNS), set up by the medical imaging department of a major Sydney teaching hospital in March 2010. This study aimed to investigate the views of the medical imaging department staff about: (i) the results follow-up problem encountered by the medical imaging department prior to the implementation of the RNS; (ii) what changes occurred following implementation of the RNS; and (iii) suggestions for improving the RNS. METHODS: This is a cross-sectional qualitative study incorporating semi-structured interviews with 16 staff (15 radiologists and 1 clerk) after the implementation of the RNS. Interviews were conducted in August/September 2011. RESULTS: The reasons behind the development of the RNS were related to: (i) major existing problems with the communication of results between the imaging department and hospital wards; (ii) cumbersome and inefficient paper-based notification systems; and (iii) the absence of standardised guidelines and procedures for radiology test notification and follow-up. The RNS managed to free up a significant proportion of radiologist time, resulting in greater efficiencies. Study participants also highlighted a number of areas for improvement, including the need for a 24-h service, feedback and acknowledgement of test results by clinicians and the standardisation of test management definitions and procedures. CONCLUSION: Test management systems can play an important part in enhancing safe and effective communications between wards and hospital departments. However, their uptake and sustainability will require the establishment of a multidisciplinary and hospital-wide collaboration that includes clinicians.

What do radiology incident reports reveal about in-hospital communication processes and the use of health information technology?

BACKGROUND: There has been recent rapid growth in the use of medical imaging leading to concerns about an increase in unnecessary investigations, patient exposure to radiation, and incorrect diagnoses. Incident reporting systems provide a portal for staff to catalogue adverse events which occur within a hospital or department. Analysing incident reports can reveal trends and provide guidance for quality improvement efforts. METHODS: Classification of medical imaging related-incidents from a major teaching hospital in Sydney, Australia using WHO International Classification for Patient Safety (ICPS) taxonomy. All incidents with radiology identified as incident location (n=219) were extracted. Incidents were from January 2005 to October 2011. Two researchers independently cleaned the data set. One researcher then applied the ICPS to free text incident reports. RESULTS: 216 unique incidents were extracted. 15 incidents were unable to be classified using the ICPS. 8 incidents were classified twice, resulting in 209 coded incidents. Communication breakdown was a contributing factor in 49% (103/209) of incidents reported. 147 of the 209 incidents were associated with activities associated with data collection, storage or retrieval of electronic information. Health information technology (HIT) systems were mentioned explicitly in 10% of incidents, indicating some contribution to the error. CONCLUSIONS: Communication breakdown and HIT systems are contributors to error, and should be addressed. HIT systems need to be monitored and flaws addressed to ensure quality care.

MRI of superficial soft tissue masses: analysis of features useful in distinguishing between benign and malignant lesions.

AIM: To identify the MRI features of superficial soft tissue masses, that may allow differentiation between malignant and non-malignant lesions. METHOD: A total of 136 consecutive patients referred to a supra-regional musculoskeletal oncology center over a 10-year period with the diagnosis of a superficial soft tissue mass were included in this retrospective study. Features analyzed included patient demographics, lesion size, MRI signal characteristics, margins, lobulation, hemorrhage, necrosis, fascial edema, relationship to the fascia, as well as involvement of the skin. Comparison was then made with the final histological diagnosis. RESULTS: Of the patients reviewed, 58 were male and 78 were female, and the mean age was 49.9 years. The mean age for malignant lesions was 57.9 years, and that for non-neoplastic and benign conditions 41.9 years (p < 0.001). A significant relationship was identified between malignancy and lobulation (p < 0.01), hemorrhage (p < 0.001), fascial edema (p < 0.001), hemorrhage (p < 0.0001) and necrosis (p < 0.001). The relationship between skin thickening and skin contact and malignancy was also found to be significant. However, size was not found to be an important determining factor for malignancy, with a significant proportion of malignant superficial sarcomas measuring less than 5 cm in maximal diameter. CONCLUSIONS: This study has shown that a significant proportion of malignant superficial sarcomas measured less than 5 cm in maximal diameter. Fascial edema, skin thickening, skin contact, hemorrhage, and necrosis were found to be highly significant factors indicative of malignancy. Lobulation and peritumoral edema were also significant MRI features.

Long-term visibility of primary intracerebral hemorrhage on magnetic resonance imaging.

BACKGROUND: It is unclear whether primary intracerebral hemorrhage (PICH) remains detectable with magnetic resonance imaging (MRI) in the long term, or whether a gradient echo recalled (GRE) sequence is always necessary to detect it. METHODS: In a prospectively collected cohort of patients with stroke, we identified survivors of PICH able to undergo MRI at least 3 months after the original PICH. We compared several MRI sequences (spin echo (SE) T2, fast SE (FSE) T2 and proton density, fluid-attenuated inversion recovery, GRE) in a blinded fashion. The number of PICHs visible on each MRI sequence, and the presence of infarcts and microhemorrhages, were determined. RESULTS: In 26 patients imaged 3 years (median) after PICH, between 61% (fluid-attenuated inversion recovery) and 100% (GRE) of PICHs remained identifiable as definite PICH. On FSE T2, 3.4% of PICHs were missed. There were no specific patient features that determined which PICHs remained visible. A new PICH developed in 29% of patients between original presentation and the current study, and 38% had microhemorrhages. CONCLUSION: Although a FSE T2 sequence will identify most old PICHs, a GRE sequence is essential for definite identification. Recurrent PICH and microhemorrhages appear to be common.