Image quality and cancer visibility of T2-weighted magnetic resonance imaging of the prostate at 7 Tesla.

OBJECTIVES: To assess the image quality of T2-weighted (T2w) magnetic resonance imaging of the prostate and the visibility of prostate cancer at 7 Tesla (T). MATERIALS & METHODS: Seventeen prostate cancer patients underwent T2w imaging at 7T with only an external transmit/receive array coil. Three radiologists independently scored images for image quality, visibility of anatomical structures, and presence of artefacts. Krippendorff's alpha and weighted kappa statistics were used to assess inter-observer agreement. Visibility of prostate cancer lesions was assessed by directly linking the T2w images to the confirmed location of prostate cancer on histopathology. RESULTS: T2w imaging at 7T was achievable with 'satisfactory' (3/5) to 'good' (4/5) quality. Visibility of anatomical structures was predominantly scored as 'satisfactory' (3/5) and 'good' (4/5). If artefacts were present, they were mostly motion artefacts and, to a lesser extent, aliasing artefacts and noise. Krippendorff's analysis revealed an α = 0.44 between three readers for the overall image quality scores. Clinically significant cancer lesions in both peripheral zone and transition zone were visible at 7T. CONCLUSION: T2w imaging with satisfactory to good quality can be routinely acquired, and cancer lesions were visible in patients with prostate cancer at 7T using only an external transmit/receive body array coil. KEY POINTS: • Satisfactory to good T2-weighted image quality of the prostate is achievable at 7T. • Periprostatic lipids appear hypo-intense compared to healthy peripheral zone tissue at 7T. • Prostate cancer is visible on T2-weighted MRI at 7T.

The predictive value of endorectal 3 Tesla multiparametric magnetic resonance imaging for extraprostatic extension in patients with low, intermediate and high risk prostate cancer.

PURPOSE: We determined the positive and negative predictive values of multiparametric magnetic resonance imaging for extraprostatic extension at radical prostatectomy for different prostate cancer risk groups. MATERIALS AND METHODS: We evaluated a cohort of 183 patients who underwent 3 Tesla multiparametric magnetic resonance imaging, including T2-weighted, diffusion weighted magnetic resonance imaging and dynamic contrast enhanced sequences, with an endorectal coil before radical prostatectomy. Pathological stage at radical prostatectomy was used as standard reference for extraprostatic extension. The cohort was classified into low, intermediate and high risk groups according to the D'Amico criteria. We recorded prevalence of extraprostatic extension at radical prostatectomy and determined sensitivity, specificity, positive predictive value and negative predictive value of multiparametric magnetic resonance imaging for extraprostatic extension in each group. Univariate and multivariate analyses were performed to identify predictors of extraprostatic extension at radical prostatectomy. RESULTS: The overall prevalence of extraprostatic extension at radical prostatectomy was 49.7% ranging from 24.7% to 77.1% between low and high risk categories. Overall staging accuracy of multiparametric magnetic resonance imaging for extraprostatic extension was 73.8%, with sensitivity, specificity, positive predictive value and negative predictive value of 58.2%, 89.1%, 84.1% and 68.3%, respectively. Positive predictive value of multiparametric magnetic resonance imaging for extraprostatic extension was best in the high risk cohort with 88.8%. Negative predictive value was highest in the low risk cohort with 87.7%. With an odds ratio of 10.3 multiparametric magnetic resonance imaging is by far the best preoperative predictor of extraprostatic extension at radical prostatectomy. CONCLUSIONS: For adequate patient counseling, knowledge of predictive values of multiparametric magnetic resonance imaging for extraprostatic extension is of utmost importance. High negative predictive value, important for decisions on nerve sparing strategies at radical prostatectomy, is only reached in low risk subjects.

Imaging vascular function for early stage clinical trials using dynamic contrast-enhanced magnetic resonance imaging.

Many therapeutic approaches to cancer affect the tumour vasculature, either indirectly or as a direct target. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has become an important means of investigating this action, both pre-clinically and in early stage clinical trials. For such trials, it is essential that the measurement process (i.e. image acquisition and analysis) can be performed effectively and with consistency among contributing centres. As the technique continues to develop in order to provide potential improvements in sensitivity and physiological relevance, there is considerable scope for between-centre variation in techniques. A workshop was convened by the Imaging Committee of the Experimental Cancer Medicine Centres (ECMC) to review the current status of DCE-MRI and to provide recommendations on how the technique can best be used for early stage trials. This review and the consequent recommendations are summarised here. Key Points • Tumour vascular function is key to tumour development and treatment • Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can assess tumour vascular function • Thus DCE-MRI with pharmacokinetic models can assess novel treatments • Many recent developments are advancing the accuracy of and information from DCE-MRI • Establishing common methodology across multiple centres is challenging and requires accepted guidelines.

Automated 3-dimensional segmentation of pelvic lymph nodes in magnetic resonance images.

PURPOSE: Computer aided diagnosis (CAD) of lymph node metastases may help reduce reading time and improve interpretation of the large amount of image data in a 3-D pelvic MRI exam. The purpose of this study was to develop an algorithm for automated segmentation of pelvic lymph nodes from a single seed point, as part of a CAD system for the classification of normal vs metastatic lymph nodes, and to evaluate its performance compared to other algorithms. METHODS: The authors' database consisted of pelvic MR images of 146 consecutive patients, acquired between January 2008 and April 2010. Each dataset included four different MR sequences, acquired after infusion of a lymph node specific contrast medium based on ultrasmall superparamagnetic particles of iron oxide. All data sets were analyzed by two expert readers who, reading in consensus, annotated and manually segmented the lymph nodes. The authors compared four segmentation algorithms: confidence connected region growing (CCRG), extended CCRG (ECC), graph cut segmentation (GCS), and a segmentation method based on a parametric shape and appearance model (PSAM). The methods were ranked based on spatial overlap with the manual segmentations, and based on diagnostic accuracy in a CAD system, with the experts' annotations as reference standard. RESULTS: A total of 2347 manually annotated lymph nodes were included in the analysis, of which 566 contained a metastasis. The mean spatial overlap (Dice similarity coefficient) was: 0.35 (CCRG), 0.57 (ECC), 0.44 (GCS), and 0.46 (PSAM). When combined with the classification system, the area under the ROC curve was: 0.805 (CCRG), 0.890 (ECC), 0.807 (GCS), 0.891 (PSAM), and 0.935 (manual segmentation). CONCLUSIONS: We identified two segmentation methods, ECC and PSAM, that achieve a high diagnostic accuracy when used in conjunction with a CAD system for classification of normal vs metastatic lymph nodes. The manual segmentations still achieve the highest diagnostic accuracy.

The impact of preoperative breast MRI on the re-excision rate in invasive lobular carcinoma of the breast.

Re-excision rates after breast conserving surgery(BCS) of invasive lobular carcinoma (ILC) are high.Preoperative breast MRI has the potential to reduce re-excision rates, but may lead to an increased rate of mastectomies. Hence, we assessed the influence of preoperative breast MRI on the re-excision rate and the rate of mastectomies. We performed a retrospective cohort study of a consecutive series of patients with ILC who presented in one of two dedicated tertiary cancer centers between 1993 and 2005. We assessed the initial type of surgery(BCS or mastectomy), the re-excision rate and the final type of surgery. Patients were stratified into two groups:those who received preoperative MRI (MR? group) and those who did not (MR- group). In the MR- group, 27%of the patients underwent a re-excision after initial BCS. In the MR? group, this rate was significantly lower at 9%.The odds ratio was 3.64 (95% CI: 1.30-10.20, P = 0.010).There was a trend towards a lower final mastectomy rate in the MR? group compared to the MR- group (48 vs. 59%,P = 0.098). In conclusion, preoperative MRI in patients with ILC can reduce re-excision rates without increasing the rate of mastectomies.

[Robot-controlled MRI-guided transrectal prostate biopsy, a promising technique]. / Robotgestuurde MRI-geleide transrectale prostaatbiopsie.

At the so-called in-bore, MRI-guided prostate biopsy, the radiologist in the MRI suite manually directs a rectal biopsy needle guide at an abnormality confirmed by a previous prostate MRI. This manual technique of taking a biopsy is time-consuming and thus rather expensive, as the patient has to be moved in and out of the MRI several times. Since 2015, a remote-controlled manipulator robot (RCM) has been available. Using this apparatus the radiologist is able to position the needle guide remotely. This technique is simple to learn and less time-consuming than the in-bore biopsy without the RCM. In this article we discuss the findings from the first 201 patients in the Netherlands from whom robot-guided prostate biopsies have been taken.

Staging of endometrial cancer with MRI: guidelines of the European Society of Urogenital Imaging.

The purpose of this study was to define guidelines for endometrial cancer staging with MRI. The technique included critical review and expert consensus of MRI protocols by the female imaging subcommittee of the European Society of Urogenital Radiology, from ten European institutions, and published literature between 1999 and 2008. The results indicated that high field MRI should include at least two T2-weighted sequences in sagittal, axial oblique or coronal oblique orientation (short and long axis of the uterine body) of the pelvic content. High-resolution post-contrast images acquired at 2 min +/- 30 s after intravenous contrast injection are suggested to be optimal for the diagnosis of myometrial invasion. If cervical invasion is suspected, additional slice orientation perpendicular to the axis of the endocervical channel is recommended. Due to the limited sensitivity of MRI to detect lymph node metastasis without lymph node-specific contrast agents, retroperitoneal lymph node screening with pre-contrast sequences up to the level of the kidneys is optional. The likelihood of lymph node invasion and the need for staging lymphadenectomy are also indicated by high-grade histology at endometrial tissue sampling and by deep myometrial or cervical invasion detected by MRI. In conclusion, expert consensus and literature review lead to an optimized MRI protocol to stage endometrial cancer.

Prostate cancer imaging.

As prostate cancer is a biologically heterogeneous disease for which a variety of treatment options are available, the major objective of prostate cancer imaging is to achieve more precise disease characterization. Magnetic resonance imaging (MRI) may enhance the staging of prostate cancer compared with clinical evaluation, transrectal ultrasound, or computed tomography (CT), and allows concurrent evaluation of prostatic, periprostatic, and pelvic anatomy. In clinical practice, the fusion of MRI or dynamic contrast-enhanced MRI (DCE-MRI) with MR spectroscopic imaging (MRSI) is improving the evaluation of cancer location, size, and extent, while providing an indication of tumor aggressiveness. Pretreatment knowledge of these prognostic variables is essential for achieving minimally invasive, patient-specific therapy.

Magnetic resonance imaging and mammography in women with a hereditary risk of breast cancer.

BACKGROUND: Although breast cancer screening is recommended to start at a younger age for women with a hereditary risk of breast cancer, the sensitivity of mammography for these women is reduced. We compared magnetic resonance imaging (MRI) with mammography to determine which is more sensitive and whether MRI could play a role in the early detection of breast cancer for these women. METHODS: We constructed a retrospective cohort of all breast MRI and mammography surveillance reports made in our department from November 1994 to February 2001. All of the 179 women in the cohort had received biannual palpation in addition to annual imaging by MRI, mammography, or both. The 258 MRI images and the 262 mammograms were classified with the use of the BI-RADS (i.e., Breast Imaging Reporting and Data System) scoring system, which has five categories to indicate the level of suspicion of a lesion. Receiver operator characteristic curves were generated for MRI and mammography, and the area under each curve (AUC) was assessed for the entire cohort of 179 women and for a subset of 75 women who had received both an MRI and a mammographic examination within a 4-month period. All statistical tests were two-sided. RESULTS: In the cohort of 179 women, we detected 13 breast cancers. Seven cancers were not revealed by mammography, but all were detected by MRI. For the entire cohort, the AUC for mammography was 0.74 (95% confidence interval [CI] = 0.68 to 0.79), and the AUC for MRI was 0.99 (95% CI = 0.98 to 1.0). For the subset of women who had both examinations, the AUC for mammography was 0.70 (95% CI = 0.60 to 0.80), and the AUC for MRI was 0.98 (95% CI = 0.95 to 1.0). CONCLUSION: MRI was more accurate than mammography in annual breast cancer surveillance of women with a hereditary risk of breast cancer. Larger prospective studies to examine the role of MRI in screening programs are justified.

Mammographic detection and staging of invasive lobular carcinoma.

The aim of the study was to evaluate mammography in detecting and staging of invasive lobular carcinoma (ILC) in order to assess the performance and impact of observer variability. Forty-two cases of ILC were retrospectively evaluated twice by two breast radiologists. Mammographic performance as well as intra- and interobserver variations was evaluated. Thirty-five percent to 37% of the cases were understaged. The largest differences between radiologists were found in the breast imaging reporting and data system (BIRADS) classification and staging performance. These results can have serious influence on patient management.

The value of tests predicting renovascular hypertension in patients with renal artery stenosis treated by angioplasty.

The aim of this study was to evaluate tests predicting renovascular hypertension. This was done by relating the results of renal vein renin tests, the captopril test, and renal scintigraphic tests to the blood pressure outcome 12 months after relief of renal artery stenosis by percutaneous transluminal renal angioplasty in 31 patients. Cure was seen in eight (26%). Improved blood pressure was obtained in 12 patients (39%), and in 11 patients (35%), the result for blood pressure was a failure. The accuracies of the two mathematical models used to analyze the renal vein renin assays were 44% and 60%. The captopril test showed a sensitivity of 36% and an accuracy of 43%. Renal captopril technetium Tc 99m-labeled pentetic acid scintigraphy gave a sensitivity of 60%. Stepwise logistic regression analysis of clinical variables in relation to blood pressure response revealed age as the only factor significantly related to blood pressure outcome. We conclude that the tests used are unfit for helping select patients for percutaneous transluminal renal angioplasty and that age may have an important influence on outcome.

Pitfalls in Interpreting mp-MRI of the Prostate: A Pictorial Review with Pathologic Correlation.

OBJECTIVES: The purpose of this pictorial review is to present a wide spectrum of prostate multiparametric MRI (mp-MRI) pitfalls that may occur in clinical practice, with radiological and pathological correlation. METHODS: All examinations were performed according to ESUR Guidelines protocols. RESULTS AND CONCLUSION: mp-MRI imaging of the prostate often leads to interpreting doubts and misdiagnosis due to the many interpretative pitfalls that a tissue, whether healthy or treated, may cause. These "false-positive" findings may occur in each stage of the disease history, from the primary diagnosis and staging, to the post-treatment stage, and whether they are caused by the tissue itself or are iatrogenic, their recognition is critical for proper treatment and management. Knowledge of these known pitfalls and their interpretation in the anatomical-radiological context can help radiologists avoid misdiagnosis and consequently mistreatment. MAIN MESSAGES: • Some physiological changes in the peripheral and central zone may simulate prostate cancer. • Technical errors, such as mispositioned endorectal coils, can affect the mp-MRI interpretation. • Physiological changes post-treatment can simulate recurrence.

Pulmonary function before surgery for pectus excavatum and at long-term follow-up.

Pulmonary function tests were performed before surgery on 152 patients who were operated on for pectus excavatum between 1970 and 1987 and at long-term follow-up to assess the degree of impairment and to investigate any changes caused by surgical correction. The mean age at surgery was 15.3 +/- 5.5 years. Pulmonary function was found to be restricted preoperatively. Multivariate analysis showed that preoperative pulmonary function was not related to age, the severity of the deformity at physical examination, or to pulmonary complaints. Only the patients with obstructive disease showed significantly more pulmonary complaints (p = 0.042). The total lung capacity (TLC) and inspiratory vital capacity (IVC) were significantly related to the age-corrected (delta) anteroposterior diameter of the chest (lower vertebral index [LVI]) (p = 0.0001). At follow-up (mean, 8.1 +/- 3.6 years), the restriction of pulmonary function was increased despite improvement in the symptoms of most patients and despite a significant increase in the anteroposterior diameter of the chest (p = 0.0001): the TLC was decreased from 83.7 percent predicted (pred) preoperatively to 73.8 percent pred (p = 0.0001) and the IVC from 78.3 percent pred to 70.7 percent pred (p = 0.0001). The surgical results were satisfactory in 83.6 percent. No relation was found between the changes in pulmonary function measured at follow-up and the surgical results. Only the age at surgery and the changes in the TLC and IVC at follow-up were significantly related (p = 0.0036, 0.0043, respectively), although the correlation coefficients were low (r = 27 percent and 28 percent, respectively). The reduction in lung function at follow-up was most pronounced in the patients who had the least functional impairment (TLC > 75 percent pred) preoperatively. No correlation was found between the changes in the pulmonary function test results at follow-up and follow-up interval, preoperative delta LVI, and the change in delta LVI at follow-up.

Exercise cardiorespiratory function before and one year after operation for pectus excavatum.

In 35 patients with pectus excavatum (aged 17.9 +/- 5.6 years) pulmonary function and maximal exercise test results were compared before and at 1 year after operation. The lower posteroanterior chest diameter on the lateral x-ray film was significantly smaller than normal (p < 0.0001) and increased significantly after operation (p < 0.0001). Preoperatively, total lung capacity (86.0% +/- 14.4%; p = 0.0001) and inspiratory vital capacity (79.7% +/- 16.2; p = 0.0001) were significantly smaller than predicted and further decreased after operation (-9.2% +/- 9.2%; p = 0.0001 and -6.6% +/- 10.7%; p = 0.0012, respectively). Arterial blood gas values displayed normal patterns with increasing exercise both before and after operation. Only the arterial pH decreased more after operation than before (p = 0.0026). After operation there was a significant increase in maximal oxygen uptake (oxygen uptake; p = 0.0002 and oxygen uptake per kilogram; p = 0.0025) and oxygen pulse (oxygen uptake/heart rate approximates an indirect parameter for stroke volume; p = 0.0333) during exercise, whereas the maximal work performed was unchanged. Efficiency of breathing (ratio of tidal volume/inspiratory vital capacity) at maximal exercise improved significantly after operation (p = 0.0005). Ventilatory limitation of exercise (defined by an increase in carbon dioxide tension during exercise) was found in 43.9% of the patients before operation. A tendency of improvement was noted (not significant) after operation (difference in carbon dioxide tension 0.6 +/- 0.4 kPa before versus 0.3 +/- 0.5 kPa after operation). However, the group with normal preoperative carbon dioxide elimination had a ventilatory limitation of exercise after operation (difference in carbon dioxide tension -0.4 +/- 0.3 kPa before versus -0.1 +/- 0.3 kPa after operation; p = 0.0128) with a significant increase in oxygen consumption (p = 0.0007). In conclusion the subjective physical improvement after operation is not explained by changes in cardiorespiratory function at exercise. The data suggest a higher work of breathing after operation.

Coarctation developing after arterial switch repair for transposition of the great arteries.

We describe 2 patients with simple transposition of the great arteries in whom coarctation of the aorta developed after uncomplicated arterial switch operation. Both patients showed no symptoms or signs of this coarctation at the time of arterial switch operation.

What is new in bladder cancer imaging.

Treatment and prognosis of urinary bladder cancer largely are determined by the tumor stage and presence of metastases. MR imaging and clinical staging complement each other. MR imaging is the most accurate technique for differentiating the various stages of deep tumor infiltration and detection of metastases, whereas clinical staging is the best technique for differentiating between postbiopsy effects and the various stages of superficial tumors. The role of MR imaging in staging of this disease and monitoring of therapy is reviewed and illustrated. Finally, the authors present an overview of current and future applications of this technique.

Occlusion of unilateral stenosed renal arteries--relation to medical treatment.

In 78 patients we studied retrospectively the occurrence of occlusion in unilateral renal artery stenosis during antihypertensive drug treatment. Complete occlusion occurred in 14 patients (18%). In a multivariate analysis the following characteristics were included: blood pressure, aetiology of the stenosis, serum creatinine, the degree of the stenosis, anti-hypertensive medication, standing renal vein renin ratio and age. In this analysis the combination of a diuretic and an ACE-inhibitor, during the observation period, showed an independent relation to the development of an occlusion (P less than 0.05). Also the ACE-inhibitor alone showed a relation (P = 0.06). In the 14 patients who developed an occlusion only three showed a significant rise in serum creatinine. We conclude that special attention should be given to the follow-up of patients with renal artery stenosis who have ACE-inhibitors in their treatment regimen, especially when in combination with a diuretic.

Radioiodine for nontoxic multinodular goiter.

Surgery is considered standard therapy for nontoxic goiter. However, surgical treatment of large goiters is not without risk, especially in elderly patients and in those with cardiopulmonary diseases. Therefore, in recent years interest in 131I treatment of nontoxic goiter has increased. Studies, using ultrasonography and magnetic resonance imaging (MRI) for accurate measurements of thyroid volume, have shown that 131I treatment of nontoxic nodular goiter results in a mean thyroid volume reduction of 40% after 1 year of 50-60% after 3-5 years. Moreover, an improvement of compressive symptoms can be achieved. This has been objectified by a significant decrease in tracheal compression as measured by MRI. Early side effects due to radiation thyroiditis usually are mild. The development of autoimmune hyperthyroidism occurring several months after 131I therapy in approximately 5% of patients is the most important complication of 131I therapy for nontoxic goiter. The incidence of post-treatment hypothyroidism appears to be approximately 20-30% at 5 years. For elderly people, the lifetime risk of fatal and nonfatal cancer induced by this therapy (administered activity 1.9 +/- 0.9 GBq of 131I) was estimated to be approximately 0.5%. In all patients with nontoxic multinodular goiter the estimated risks of both surgery and radioiodine therapy should be weighed carefully. In younger patients surgery still is to be preferred, especially when the amount of 131I to be administered is high. However, for elderly patients, especially those with cardiopulmonary disease, the profits of radioiodine treatment will outweigh the lifetime risk of this mode of therapy.

In vivo proton MR spectroscopy reveals altered metabolite content in malignant prostate tissue.

BACKGROUND: Recently the potential of magnetic resonance (MR) methods for non-invasive diagnosis and therapy evaluation of prostate cancer has improved substantially. In this study proton MR spectroscopy (1H MRS) was explored for the detection of cancer in the prostate. PATIENTS AND METHODS: Employing an endorectal probe localized 1H MRS and contrast enhanced MR imaging was performed on the prostate of healthy volunteers and of patients with benign prostatic hyperplasia (BPH) and/or prostate cancer (PCa). RESULTS: 1H MR spectra of the human prostate showed major signals for citrate, creatine and choline compounds. For cancer tissue the average citrate/choline signal ratio was significantly lower than for BPH and non-cancerous peripheral and central zone tissue, but individual ratios overlapped with ratios for normal central zone and BPH tissue. Low citrate/choline ratios in tumour tissue correspond with early MR contrast enhancement. CONCLUSIONS: 1H MRS has potential for non-invasive detection and follow-up of tumours in the prostate.

Diagnosis and management of the coronary-subclavian steal syndrome.

A patient is presented with recurrent angina due to a coronary-subclavian steal syndrome 3 years after left internal mammary to left anterior descending coronary artery bypass grafting. Myocardial ischaemia could easily be provoked by selective exercise of the left upper limb. Coronary angiography showed reversal of flow in the left internal mammary artery. Suggestions are given for prevention of the coronary-subclavian steal syndrome by identification of patients who are at risk of developing subclavian artery occlusive disease. Performance of coronary and brachiocephalic angiography is indicated in recurrence of angina in patients with internal mammary artery bypass grafts. Doppler spectral analysis may be a valuable technique for detection of a haemodynamically significant stenosis of the left subclavian artery. Carotid-subclavian bypass grafting is the procedure of choice for management of the coronary-subclavian steal syndrome.