David J. Lomas

Dynamic contrast-enhanced MRI as a predictor of tumour response to radiotherapy.

A predictive technique in the management of patients with cancer could improve the therapeutic index by allowing better individualisation of treatment. The standard risk factors that are currently used do not adequately account for the unpredictable and substantial variation seen in the treatment response of patients with a similar risk profile. Dynamic contrast-enhanced (DCE) MRI is a non-invasive technique that can provide anatomical and physiological information on the tumour. The DCE-MRI data reflects the tumour microenvironment variables that are known to influence radiation response. The aim of this review is to describe the potential clinical application of DCE-MRI as a predictor of radiation response. We have reviewed the literature and identified 29 studies (total of 1194 patients) that correlate DCE-MRI with histopathological or clinical outcome data relevant to radiotherapy.

MRI of Malignant Neoplasms of the Uterine Corpus and Cervix

OBJECTIVE In this article, we review the role of MRI in the imaging of malignant neoplasms of the uterine corpus and cervix, describing its role in staging, treatment planning, and follow-up. CONCLUSION MRI is not officially incorporated in the International Federation of Gynecology and Obstetrics (FIGO) staging system, but is already widely accepted as the most reliable imaging technique for the diagnosis, staging, treatment planning, and follow-up of both endometrial and cervical cancer. MRI protocols need to be optimized to obtain the best results and avoid pitfalls.

Semiquantitative and quantitative dynamic contrast-enhanced magnetic resonance imaging measurements predict radiation response in cervix cancer

PURPOSE To evaluate semiquantitative and quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measurements in predicting the response to radiotherapy in cervix cancer. METHODS AND MATERIALS Patients with cervix cancer treated radically with chemoradiotherapy had DCE-MRI at three time points: before starting treatment, after 2 weeks of radiotherapy, and in the 5th week of radiotherapy. Semiquantitative measurements obtained from the signal intensity vs. time plots included arrival time of contrast, the slope and maximum slope of contrast uptake, time for peak enhancement, and the contrast enhancement ratio (CER). Pharmacokinetic modeling with a modeled vascular input function was used for the quantitative measurements volume transfer constant (K(trans)), rate constant (k(ep)), fraction plasma volume (fPV), and the initial area under gadolinium-time curve. The correlation of these measurements at each of the three time points with radiologic tumor response was investigated. RESULTS Thirteen patients had a total of 38 scans. There was no correlation between the DCE-MRI measurements and the corresponding tumor volumes. A statistically significant correlation with percentage tumor regression was shown with the pretreatment DCE-MRI semiquantitative parameters of peak time (p = 0.046), slope (p = 0.025), maximum slope (p = 0.046), and CER (p = 0.025) and the quantitative parameters K(trans) (p = 0.043) and k(ep) (p = 0.022). Second and third scan measurements did not show any correlation. CONCLUSIONS This is the first study to show that pretreatment DCE-MRI quantitative parameters predict the radiation response in cervix cancer. These measurements may allow a more meaningful comparison of DCE-MRI studies from different centers.

Evaluation of Depth of Myometrial Invasion and Overall Staging in Endometrial Cancer: Comparison of Diffusion-weighted and Dynamic Contrast-enhanced MR Imaging

PURPOSE To compare the diagnostic performance of diffusion-weighted (DW) magnetic resonance (MR) imaging with that of dynamic contrast material-enhanced (DCE) MR imaging in evaluating the depth of myometrial invasion and overall stage in patients with endometrial cancer. MATERIALS AND METHODS The institutional review board approved this retrospective study; patient consent was not required. From May 2008 to February 2010, 48 women with endometrial cancer underwent preoperative MR imaging, including T1- and T2-weighted imaging, DW MR imaging (b=0 and 800 sec/mm2) and DCE MR imaging. Two radiologists independently interpreted the depth of myometrial invasion, overall stage, and presence of pitfalls associated with inaccurate assessment of myometrial invasion at T1- and T2-weighted imaging, DW MR imaging, and DCE MR imaging. Myometrial invasion and overall stage were compared by using the McNemar test, and κ statistics were used for reader agreement. RESULTS For assessing the depth of myometrial invasion, diagnostic accuracy, sensitivity, and specificity, respectively, were as follows: DW MR imaging-reader 1, 90%, 84%, and 100%; reader 2, 85%, 84%, and 88%; DCE MR imaging-reader 1, 71%, 61%, and 88%; reader 2, 79%, 77%, and 82%. The improvement in diagnostic accuracy for reader 1 was significant (P=.035). For myometrial invasion, κ values were 0.75 with DW MR imaging and 0.26 with DCE MR imaging. There was no association between inaccurate assessment of myometrial invasion and standard pitfalls with DW MR imaging. Readers 1 and 2 correctly staged more patients by using DW MR imaging (39 and 38 patients, respectively) than by using DCE MR imaging (29 and 30 patients, respectively) (P<.05). For overall stage, κ values were 0.74 with DW MR imaging and 0.22 with DCE MR imaging. CONCLUSION DW MR imaging has superior diagnostic accuracy in the assessment of myometrial invasion and significantly higher staging accuracy compared with DCE MR imaging.

Magnetic resonance imaging of the knee: Diagnostic performance statistics

Abstract Objectives: To review and reassess the published diagnostic performance statistics for MRI of the menisci and cruciate ligaments. To illustrate the potential sources and effects of bias in the evaluation of this widely accepted diagnostic technique. Methods: Published evaluations of knee MRI were identified from the literature. Criteria for inclusion in the review were a total sample size ≥ 35, arthroscopic correlation of MRI findings and presentation of complete results. Diagnostic performance statistics were then recalculated for each published study. Results: Twenty-two studies were identified with sample sizes between 35 and 1014. The overall sensitivity for MRI of the menisci and cruciates was 0.88 (95% confidence interval 0.86–0.90). The overall specificity was 0.94 (0.93–0.94). Sampling error varied widely amongst studies and was rarely quantified. Conclusions: Diagnostic performance statistics are widely used. It is still not well appreciated that these are subject to sampling error. Such errors make meaningful comparisons between published studies more difficult. Nevertheless, the results for meniscal and cruciate lesions are consistently high and support the use of MRI for these common problems. The diagnostic performance of other applications of MRI should be subjected to similar critical review.

How reliable is modern breast imaging in differentiating benign from malignant breast lesions in the symptomatic population

AIM To assess the ability of mammography and ultrasound individually and in combination to predict whether a breast abnormality is benign or malignant in patients with symptomatic breast disease. MATERIALS AND METHODS Patients included were those in whom histological confirmation of the abnormality following surgical excision was available. Mammographic and ultrasound appearances were prospectively classified using a four-point scale (1 = no significant lesion, 2 = benign lesion, 3 = possibly malignant, 4 = probably malignant). RESULTS Histological confirmation following surgical excision was available in 559 patients, of which 303 were benign and 256 were malignant. The imaging classification was correlated with histology in these 559 lesions. In predicting final histology, the sensitivity and specificity of mammography alone were 78.9 and 82.7%, respectively, of ultrasound alone were 88.9 and 77.9%, respectively, and of mammography and ultrasound in combination were 94.2 and 67.9%, respectively. Only one patient had both a mammogram and ultrasound reported as normal (category 1 for both tests) in whom subsequent histology revealed a carcinoma (0.4% of all carcinomas). CONCLUSION We found that the extensive use of ultrasound increases the cancer detection rate in this selected population by 14%.

MR cholangiopancreatography: prospective comparison of a breath-hold 2D projection technique with diagnostic ERCP.

Abstract. The aim of this study was to compare prospectively a breath-hold projection magnetic resonance cholangiopancreatography (MRCP) technique with diagnostic endoscopic retrograde cholangiopancreatography (ERCP). Seventy-six patients with suspected strictures or choledocholithiasis were referred for MRCP and subsequent ERCP examination, which were performed within 4 h of each other. The MRCP technique was performed using fat-suppressed rapid acquisition with relaxation enhancement (RARE) projection images obtained in standardised planes with additional targeted projections as required by the supervising radiologist. Two radiologists (in consensus) assessed the MRCP results prospectively and independently for the presence of bile duct calculi, strictures, non-specific biliary dilatation and pancreatic duct dilatation, and recorded a single primary diagnosis. The ERCP was assessed prospectively and independently by a single endoscopist and used as a gold standard for comparison with MRCP. Diagnostic agreement was assessed by the Kappa statistic. The MRCP technique failed in two patients and ERCP in five. In the remaining 69 referrals ERCP demonstrated normal findings in 23 cases, strictures in 19 cases, choledocholithiasis in 9 cases, non-specific biliary dilatation in 14 cases and chronic pancreatitis in 4 cases. The MRCP technique correctly demonstrated 22 of 23 normal cases, 19 strictures with one false positive (sensitivity 100 %, specificity 98 %), all 9 cases of choledocholithiasis with two false positives (sensitivity 100 %, specificity 97 %), 12 of 14 cases of non-specific biliary dilatation and only 1 of 4 cases of chronic pancreatitis. There was overall good agreement for diagnosis based on a kappa value of 0.88. Breath-hold projection MRCP can provide non-invasively comparable diagnostic information to diagnostic ERCP for suspected choledocholithiasis and biliary strictures and may allow more selective use of therapeutic ERCP.

Advanced Ovarian Cancer: Multiparametric MR Imaging Demonstrates Response- and Metastasis-specific Effects

PURPOSE To investigate the role of multiparametric magnetic resonance (MR) imaging in the evaluation of response to platinum-based neoadjuvant chemotherapy in advanced ovarian cancer and to compare imaging parameters between primary ovarian mass and metastatic disease. MATERIALS AND METHODS Evaluable patients suspected of having advanced ovarian carcinoma were enrolled in a prospective protocol-driven study. Research ethics committee approval and written informed consent were obtained. Multiparametric MR imaging (diffusion-weighted MR imaging, dynamic contrast material-enhanced [DCE] MR imaging, and hydrogen 1 MR spectroscopy) was performed with a 3.0-T wholebody MR imaging system. Three marker lesions-primary ovarian mass, omental cake, and peritoneal deposit-were outlined by a radiologist on apparent diffusion coefficient (ADC) and vascular signal fraction (VSF) maps and on DCE MR images. Comparisons of mean ADC, mean VSF, DCE MR imaging parameters, and choline concentration between responders and nonresponders were based on Response Evaluation Criteria in Solid Tumors and CA-125 criteria. RESULTS Twenty-two patients were evaluable. The mean ADC for peritoneal metastases was lower than that for ovarian (P = .015) and omental (P = .006) sites. There were no differences in pretreatment DCE MR imaging parameters between tumor sites. After treatment, responders showed a significantly larger increase in ADC (P = .021) and fractional volume of the extravascular extracellular space (v(e)) (P = .025) of ovarian lesions compared with nonresponders, but there was no change in ADC at other sites. Pre- and posttreatment values of choline concentration of ovarian lesions were lower in responders (P = .025) than in nonresponders (P = .010). CONCLUSION The significant differences in baseline ADCs among primary ovarian cancer, omental cake, and peritoneal deposits indicate that diffusivity profiles may be tumor-site dependent, suggesting biologic heterogeneity of disease. ADC and v(e) parameters correlated with the cytotoxic effects of platinum-based therapy and may be useful response markers, while choline concentration predicted but did not reflect response.

Apparent diffusion coefficient and vascular signal fraction measurements with magnetic resonance imaging: feasibility in metastatic ovarian cancer at 3 Tesla

This prospective study aims to evaluate the feasibility of DWI at 3 Tesla in patients with advanced ovarian cancer and investigate the differences in vascular signal fraction (VSF) and apparent diffusion coefficient (ADC) values between primary ovarian mass and metastatic disease. Twenty patients with suspected advanced ovarian carcinoma were enrolled in the study. High-resolution T2W FRFSE images were used to confirm the position of three marker lesions: primary ovarian mass, omental cake and peritoneal deposit. Multislice DWI was acquired in a single breath-hold using multiple b-values. The three marker lesions were outlined by an experienced radiologist on ADC and VSF maps. Ovarian lesions showed the highest ADC values. The mean ADC value for peritoneal deposits was significantly lower than for both ovarian lesions (p = 0.03) and omental cake (p = 0.03). The VSF for omental cake was significantly higher than for ovarian lesions (p = 0.01) and peritoneal deposits (p = 0.04). There was a significant positive correlation between ADC and VSF for peritoneal deposits (p = 0.04). DWI in advanced ovarian cancer is feasible at 3 T. There are significant differences in baseline ADC and VSF values between ovarian cancer, omental cake and peritoneal deposits that may explain the mixed treatment response that occurs at different disease sites.

Minimally‐invasive fetal autopsy using magnetic resonance imaging and percutaneous organ biopsies: clinical value and comparison to conventional autopsy

Autopsy is an important investigation following fetal death or termination for fetal abnormality. Postmortem magnetic resonance imaging (MRI) can provide macroscopic information of comparable quality to that of conventional autopsy in the event of perinatal death. It does not provide tissue for histological examination, which may limit the quality of counseling for recurrence risks and elucidation of the cause of death. We sought to examine the comparability and clinical value of a combination of postmortem MRI and percutaneous fetal organ biopsies (minimally invasive autopsy (MIA)) with conventional fetal autopsy.