Analysis of the correlation between endorectal MRI response to neoadjuvant chemotherapy and biochemical recurrence in patients with high-risk localized prostate cancer

BACKGROUND

Intermediate end points are desirable to expedite the integration of neoadjuvant systemic therapy into the treatment strategy for high-risk localized prostate cancer. Endorectal magnetic resonance imaging at 1.5 Tesla (1.5T erMRI) response has been utilized as an end point in neoadjuvant trials but has not been correlated with clinical outcomes.

METHODS

Data were pooled from two trials exploring neoadjuvant chemotherapy in high-risk localized prostate cancer. Trial 1 explored docetaxel for 6 months and Trial 2 explored docetaxel plus bevacizumab for 4.5 months, both before radical prostatectomy. erMRI was done at baseline and end of chemotherapy. 1.5T erMRI response, based upon T2W sequences, was recorded. Multivariable Cox regression was undertaken to evaluate the association between clinical parameters and biochemical recurrence.

RESULTS

There were 53 evaluable patients in the combined analysis: 20 (33%) achieved a PSA response, 16 (27%) achieved an erMRI partial response and 24 (40%) achieved an erMRI minor response. Median follow-up was 4.2 years, and 33 of 53 evaluable (62%) patients developed biochemical recurrence. On multivariable analysis, PSA response did not correlate with biochemical recurrence (hazard ratio=0.58, 95% confidence interval (CI) 0.25-1.33) and paradoxically erMRI response was associated with a significantly shorter time to biochemical recurrence (hazard ratio=2.47, 95% CI 1.00-6.13).

CONCLUSIONS

Response by 1.5T erMRI does not correlate with a decreased likelihood of biochemical recurrence in patients with high-risk localized prostate cancer treated with neoadjuvant docetaxel and may be associated with inferior outcomes. These data do not support the use of 1.5T erMRI response as a primary end point in neoadjuvant chemotherapy trials.

A phase II study of neoadjuvant chemotherapy with docetaxel and bevacizumab in patients (pts) with high-risk localized prostate cancer: A Prostate Cancer Clinical Trials Consortium trial

5060

Background: Treatment options for high-risk localized prostate cancer remain inadequate, with the majority of pts relapsing despite surgery or radiation therapy. We conducted a phase II multicenter trial of neoadjuvant docetaxel and bevacizumab prior to radical prostatectomy in pts with high risk localized prostate cancer. Methods: Eligibility included any of the following: PSA > 20 ng/ml or PSA velocity > 2 ng/ml/yr, cT3 disease, any biopsy Gleason 8–10, Gleason 7 with T3 disease by endorectal (er) MRI. Also, >50% biopsy cores involved and either Gleason 7 or PSA >10 or cT2 disease were eligible. Pts were treated with docetaxel 70 mg/m2 q 3weeks x 6 cycles and bevacizumab 15 mg/m2 q 3 weeks x 5 cycles. The primary endpoint was erMRI partial response (PR, defined here as >50% decrease in tumor volume) in a single target lesion after chemotherapy. Results: 42 pts were registered and treated with 220 cycles so far. Median age was 55 yrs (range 41–67). Median Gleason score was 8 (69% with Gleason 8–10 cancer). Median PSA was 10.5 ng/ml (range 2.1–72.5). Clinical stage was T2 in 46% and T3 in 32%. Of 23 evaluable pts to date, the median decline in the maximal tumor volume by erMRI was -45% (range -84% to 110%). 9/23 (39%) patients had PR, and only 1 pt had radiographic progression. Any PSA decline was noted in 22/34 (65%) evaluable pts, with 18% having a >50% decline. Treatment was well-tolerated: 2 pts had grade 3 allergic reactions requiring discontinuation, 3 had febrile neutropenia and 1 had grade 3 hyperglycemia. Mild fatigue was common. Only 1 pt stopped treatment because of a rising PSA. To date, 31 pts have had radical prostatectomy. One had intraoperative bladder neck injury and was treated instead with radiation + hormone therapy. A second pt had an intraoperative rectal injury but completed surgery. Conclusions: Neoadjuvant docetaxel and bevacizumab demonstrates clinical evidence of activity in men with high-risk localized prostate cancer, with a 39% PR rate by erMRI and PSA declines noted in 65%. Treatment was well-tolerated. The study is ongoing and updated data on response, toxicity and pathology will be presented.

[Table: see text]

Robot-assisted needle placement in open MRI: system architecture, integration and validation

In prostate cancer treatment, there is a move toward targeted interventions for biopsy and therapy, which has precipitated the need for precise image-guided methods for needle placement. This paper describes an integrated system for planning and performing percutaneous procedures with robotic assistance under MRI guidance. A graphical planning interface allows the physician to specify the set of desired needle trajectories, based on anatomical structures and lesions observed in the patient's registered pre-operative and pre-procedural MR images, immediately prior to the intervention in an open-bore MRI scanner. All image-space coordinates are automatically computed, and are used to position a needle guide by means of an MRI-compatible robotic manipulator, thus avoiding the limitations of the traditional fixed needle template. Automatic alignment of real-time intra-operative images aids visualization of the needle as it is manually inserted through the guide. Results from in-scanner phantom experiments are provided.

Robot-assisted needle placement in open-MRI: system architecture, integration and validation

This work describes an integrated system for planning and performing percutaneous procedures-such as prostate biopsy-with robotic assistance under MRI-guidance. The physician interacts with a planning interface in order to specify the set of desired needle trajectories, based on anatomical structures and lesions observed in the patient's MR images. All image-space coordinates are automatically computed, and used to position a needle guide by means of an MRI-compatible robotic manipulator, thus avoiding the limitations of the traditional fixed needle template. Direct control of real-time imaging aids visualization of the needle as it is manually inserted through the guide. Results from in-scanner phantom experiments are provided.

Interventional and intraoperative magnetic resonance imaging

The goal of the Image Guided Therapy Program, as the name implies, is to develop the use of imaging to guide minimally invasive therapy. The program combines interventional and intraoperative magnetic resonance imaging (MRI) with high-performance computing and novel therapeutic devices. In clinical practice the multidisciplinary program provides for the investigation of a wide range of interventional and surgical procedures. The Signa SP 0.5 T superconducting MRI system (GE Medical Systems, Milwaukee, WI) has a 56-cm-wide vertical gap, allowing access to the patient and permitting the execution of interactive MRI-guided procedures. This system is integrated with an optical tracking system and utilizes flexible surface coils and MRI-compatible displays to facilitate procedures. Images are obtained with routine pulse sequences. Nearly real-time imaging, with fast gradient-recalled echo sequences, may be acquired at a rate of one image every 1.5 s with interactive image plane selection. Since 1994, more than 800 of these procedures, including various percutaneous procedures and open surgeries, have been successfully performed at Brigham and Women's Hospital (Boston, MA).

Prenatal diagnosis of pyruvate dehydrogenase deficiency using magnetic resonance imaging

INTRODUCTION

Pyruvate dehydrogenase deficiency is an inherited inborn error of metabolism associated with early neonatal death and long-term neurologic sequelae in survivors. Prenatal diagnosis currently relies on isolation of fetal cells for subsequent genetic and/or biochemical studies. Magnetic resonance imaging and magnetic resonance spectroscopy have been used on occasion for both postnatal diagnosis and management of pyruvate dehydrogenase deficiency. We illustrate a case in which these non-invasive modalities also prove useful for prenatal diagnosis of this condition.

CASE

A 31-year-old multipara with a history of two prior infants affected with pyruvate dehydrogenase deficiency presented with a spontaneous dichorionic, diamniotic twin pregnancy. Magnetic resonance imaging and magnetic resonance spectroscopy were performed on both fetuses. Magnetic resonance imaging of the presenting (male) fetus demonstrated mild ventriculomegaly, increased extracerebrospinal fluid, and decreased cortical sulcation and gyration. The non-presenting (female) fetus was structurally normal. Magnetic resonance spectroscopy spectra were obtained for both fetuses, and were normal. The diagnosis of pyruvate dehydrogenase deficiency was made in the presenting fetus after delivery on the basis of subsequent mortality from severe lactic acidosis.

CONCLUSION

Prenatal MR imaging of the fetal brain can be used for prenatal diagnosis in fetuses at risk for pyruvate dehydrogenase deficiency. Prenatal MR spectroscopy, although technically feasible, does not appear to have a role in the prenatal diagnosis of this condition.

Evaluation of three-dimensional finite element-based deformable registration of pre- and intraoperative prostate imaging

In this report we evaluate an image registration technique that can improve the information content of intraoperative image data by deformable matching of preoperative images. In this study, pretreatment 1.5 tesla (T) magnetic resonance (MR) images of the prostate are registered with 0.5 T intraoperative images. The method involves rigid and nonrigid registration using biomechanical finite element modeling. Preoperative 1.5 T MR imaging is conducted with the patient supine, using an endorectal coil, while intraoperatively, the patient is in the lithotomy position with a rectal obturator in place. We have previously observed that these changes in patient position and rectal filling produce a shape change in the prostate. The registration of 1.5 T preoperative images depicting the prostate substructure [namely central gland (CG) and peripheral zone (PZ)] to 0.5 T intraoperative MR images using this method can facilitate the segmentation of the substructure of the gland for radiation treatment planning. After creating and validating a dataset of manually segmented glands from images obtained in ten sequential MR-guided brachytherapy cases, we conducted a set of experiments to assess our hypothesis that the proposed registration system can significantly improve the quality of matching of the total gland (TG), CG, and PZ. The results showed that the method statistically-significantly improves the quality of match (compared to rigid registration), raising the Dice similarity coefficient (DSC) from prematched coefficients of 0.81, 0.78, and 0.59 for TG, CG, and PZ, respectively, to 0.94, 0.86, and 0.76. A point-based measure of registration agreement was also improved by the deformable registration. CG and PZ volumes are not changed by the registration, indicating that the method maintains the biomechanical topology of the prostate. Although this strategy was tested for MRI-guided brachytherapy, the preliminary results from these experiments suggest that it may be applied to other settings such as transrectal ultrasound-guided therapy, where the integration of preoperative MRI may have a significant impact upon treatment planning and guidance.

A practical method to achieve prostate gland immobilization and target verification for daily treatment

PURPOSE

A practical method to achieve prostate immobilization and daily target localization for external beam radiation treatment is described.

METHODS AND MATERIALS

Ten patients who underwent prostate brachytherapy using permanent radioactive source placement were selected for study. To quantify prostate motion both with and without the presence of a specially designed inflatable intrarectal balloon, the computerized tomography-based coordinates of all intraprostatic radioactive sources were compared over 3 consecutive measurements at 1-min intervals.

RESULTS

The placement and inflation of the intrarectal balloon were well tolerated by all patients. The mean (range) displacement of the prostate gland when the intrarectal balloon was present vs. absent was 1.3 (0-2.2) mm vs. 1.8 (0-9.1) mm (p = 0.03) at 2 min respectively. The maximum displacement in any direction (anterior-posterior, superior-inferior, or right-left) when the intrarectal balloon was inflated vs. absent was reduced to < or =1 mm from 4 mm.

CONCLUSIONS

Both prostate gland immobilization and target verification are possible using a specially designed inflatable intrarectal balloon. Using this device, the posterior margin necessary on the lateral fields to ensure dosimetric coverage of the entire prostate gland could be safely reduced to 5 mm and treatment could be set up and verified using a lateral portal image.

Isolated calf vein thrombosis: comparison of MR venography and conventional venography after initial sonography in symptomatic patients

RATIONALE AND OBJECTIVES

The authors performed this study to compare magnetic resonance (MR) venography and conventional venography in the diagnosis of deep venous thrombosis (DVT) in the calf after sonography.

MATERIALS AND METHODS

Sonography was performed in 595 patients who were suspected of having lower-extremity DVT. Patients with positive above-knee duplex sonograms, allergy to iodinated contrast material, renal insufficiency, or cardiac pacemakers and patients who were obese were excluded. The remaining 73 patients were asked to undergo MR venography and conventional venography. All studies were to be performed within 48 hours of the clinical diagnosis and according to standard clinical practice. Images were interpreted by radiologists who were blinded to the results of other modalities. Two separate analyses were performed: one in which conventional venography was used as the standard of reference, and one in which the presence of at least two positive studies for thrombus was considered diagnostic.

RESULTS

Although 36 patients agreed to participate in the study, only 14 underwent MR venography and conventional venography within 48 hours of the clinical diagnosis. With use of any two positive studies for confirmation, acute DVT was diagnosed in three patients. Conventional venography depicted two of the three cases, whereas sonography and MR venography each depicted all three. The findings were concordant in only five of the 14 patients.

CONCLUSION

Moderate discrepancy among modalities was demonstrated. This suggests radiologists should undertake comparisons among these three modalities for the detection of calf DVT. In patients with a high clinical suspicion, a second modality may be useful if the initial study is negative.

Bayesian regression methodology for estimating a receiver operating characteristic curve with two radiologic applications: prostate biopsy and spiral CT of ureteral stones

RATIONALE AND OBJECTIVES

The authors evaluated two Bayesian regression models for receiver operating characteristic (ROC) curve analysis of continuous diagnostic outcome data with covariates.

MATERIALS AND METHODS

Full and partial Bayesian regression models were applied to data from two studies (n = 180 and 100, respectively): (a) The diagnostic value of prostate-specific antigen (PSA) levels (outcome variable) for predicting disease after radical prostatectomy (gold standard) was evaluated for three risk groups (covariates) based on Gleason scores. (b) Spiral computed tomography was performed on patients with proved obstructing ureteral stones. The predictive value of stone size (outcome) was evaluated along with two treatment options (gold standard), as well as stone location (in or not in the ureterovesical junction [UVJ]) and patient age (covariates). Summary ROC measures were reported, and various prior distributions of the regression coefficients were investigated.

RESULTS

(a) In the PSA example, the ROC areas under the full model were 0.667, 0.769, and 0.703, respectively, for the low-, intermediate-, and high-risk groups. Under the partial model, the area beneath the ROC curve was 0.706. (b) The ROC areas for patients with ureteral stones in the UVJ decreased dramatically with age but otherwise were close to that under the partial model (ie, 0.774). The prior distribution had greater influence in the second example.

CONCLUSION

The diagnostic tests were accurate in both examples. PSA levels were most accurate for staging prostate cancer among intermediate-risk patients. Stone size was predictive of treatment option for all patients other than those 40 years or older and with a stone in the UVJ.

MR imaging-guided prostate biopsy with surgical navigation software: device validation and feasibility

Magnetic resonance (MR) imaging--guided prostate biopsy in a 0.5-T open imager is described, validated in phantom studies, and performed in two patients. The needles are guided by using fast gradient-recalled echo and T2-weighted fast spin-echo images. Surgical navigation software provided T2-weighted images critical to targeting the peripheral zone and the tumor. MR imaging can be used to guide prostate biopsy.

Three-dimensional magnetic resonance imaging of fetal brains

We assessed ten prenatal magnetic resonance imaging(MRI) scans for fetal brain anomalies, and identified eight that were suitable for post-processing. Anatomical abnormalities were assessed on three-dimensional (3D) models and compared with two-dimensional (2D) imaging. We calculated the volumes of the intracranial ventricles and of a periventricular haemorrhage. In three cases, additional clinical information was obtained. 3D modelling of the brain in-utero is possible and can be used to plan treatment.

Primary versus secondary ovarian malignancy: imaging findings of adnexal masses in the Radiology Diagnostic Oncology Group Study

PURPOSE

To analyze ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) imaging features of primary and secondary ovarian malignant neoplasms to determine if there is any significant difference in their appearance.

MATERIALS AND METHODS

Analysis of the multi-institutional Radiology Diagnostic Oncology Group data revealed 86 patients with primary ovarian carcinoma and 24 patients with a secondary ovarian neoplasm. Numerous imaging features that had been recorded for the adnexal masses with each imaging modality were reviewed and compared between primary and secondary malignant ovarian neoplasms.

RESULTS

Of the imaging features assessed with all three modalities, multilocularity as determined at US (P =.02) or MR imaging (P: =.01) was the only significant feature. At US, 30 (37%) of 81 primary ovarian cancers were multilocular, whereas only three (12%) of 24 metastatic neoplasms were multilocular. At MR imaging, 40 (74%) of 54 primary ovarian cancers were multilocular, whereas only five (36%) of 14 metastatic neoplasms were multilocular. Neither a predominately solid appearance nor bilaterality was significantly different between primary and secondary neoplasms.

CONCLUSION

For malignant ovarian masses, multilocularity at MR imaging or US favors the diagnosis of primary ovarian malignancy rather than secondary neoplasm, but it is difficult to accurately distinguish between primary and secondary ovarian malignancies.

Advances in biomedical imaging

In the 21st century, diseases will be diagnosed and treated using increasingly less invasive, more sophisticated imaging and image-guided procedures. During the past 100 years, the field of biomedical imaging has developed from Roentgen's original discovery of the x-ray to the imaging tools of today, such as magnetic resonance imaging, computed tomography, positron emission tomography, and ultrasonography. The benefits of using these sophisticated noninvasive imaging tools are already evident: more accurate and timely diagnosis of disease has translated into improved patient care. Recent advances in imaging research have shown the potential to change many aspects of clinical medicine within the next decade. Major new areas of research focus on development of the molecular, functional, cellular, and genetic imaging tools of the future, aided by new information technology and image fusion/integration capabilities. Image-guided therapy is growing rapidly, with advances in computer science, technology, and noninvasive treatment methods, such as focused ultrasonography. Undoubtedly, these and other new imaging techniques will enhance the ability to accurately diagnose and recognize disease and allow understanding of the molecular mechanisms of diseases and their respective responses to therapy. Given this explosion in new technologies, the next 25 years promise to result in dramatic changes in diagnostic imaging, particularly with respect to detection and recognition of disease.

Optimizing target coverage by dosimetric feedback during prostate brachytherapy

PURPOSE

Postimplant dosimetry of permanent prostate implants shows a loss of coverage compared to the preplan. One contributing factor is needle misplacement. The significance of needle misplacement and the clinical utility of dosimetric feedback were analyzed in the setting of interventional magnetic resonance (IMR) guided prostate brachytherapy.

METHODS AND MATERIALS

Information provided by an intraoperative planning system was analyzed for 10 patients. Needle misplacement was measured and the dosimetric consequences calculated. Additional catheters and sources were placed following the insertion of all planned catheters to compensate for nonideal needle placement.

RESULTS

Source misplacement ranged from 0.0 to 1.0 cm (median, 0.3 cm). The resulting loss of coverage ranged from 1% to 13%, and the intraoperative dosimetric feedback allowed a recovery of from 0% to 12% coverage. Between 0 and 3 (median, 2) additional needles and from 0 to 10 (median, 8) additional sources were required to restore coverage of the target. Final planned coverage exceeded 94% for all patients.

CONCLUSION

The discrepancy between planned and achieved needle placement leads to a loss of dosimetric coverage of the target volume. Dosimetric feedback allows compensation for needle divergence. The technique of real-time dosimetric feedback does not require an IMR system, and could be generalized to ultrasound-guided implants.

Feasibility of transperineal prostate biopsy under interventional magnetic resonance guidance

A patient, who was not suited for ultrasound-guided biopsy, was biopsied in an interventional magnetic resonance unit at Brigham and Women's Hospital. Real-time magnetic resonance imaging provided verification of placement before tissue samples were taken. This technique successfully sampled tissue from the prostate and led to a diagnosis of cancer.

Transperineal magnetic resonance image guided prostate biopsy

PURPOSE

We report the findings of a transperineal magnetic resonance image (MRI) guided biopsy of the prostate in a man with increasing prostate specific antigen who was not a candidate for a transrectal ultrasound guided biopsy.

MATERIALS AND METHODS

Using an open configuration 0.5 Tesla MRI scanner and pelvic coil, a random sextant sample was obtained under real time MRI guidance from the peripheral zone of the prostate gland as well as a single core from each MRI defined lesion. The patient had previously undergone proctocolectomy for ulcerative colitis and, therefore, was not a candidate for transrectal ultrasound guided biopsy. Prior attempts to make the diagnosis of prostate cancer using a transurethral approach were unsuccessful.

RESULTS

The random sextant samples contained benign prostatic hyperplasia, whereas Gleason grade 3 + 3 = 6 adenocarcinoma was confirmed in 15% and 25% of the 2 cores obtained from the MRI targeted specimens of 2 defined lesions. The procedure was well tolerated by the patient.

CONCLUSIONS

Transperineal MRI guided biopsy is a new technique that may be useful in detecting prostate cancer in men with increasing prostate specific antigen who are not candidates for transrectal ultrasound guided biopsy.

Identifying the predictors of acute urinary retention following magnetic-resonance-guided prostate brachytherapy

PURPOSE

Larger prostate gland volumes have been associated with long-term urinary morbidity in prostate interstitial radiation therapy utilizing ultrasound image guidance technique. This study was performed to identify the clinical and technical predictors of acute urinary retention following magnetic-resonance (MR)-guided prostate interstitial brachytherapy.

METHODS AND MATERIALS

Fifty patients underwent MR-guided prostate brachytherapy between December 1997 and March 1999. Patient selection was limited to men with stage T1cNXM0 disease, PSA of less than10 ng/mL, biopsy Gleason score not more than 3 + 4, and endorectal coil MR stage T2 disease. Dosimetry plans were developed in the operating room and (125)Iodine sources were implanted using MR real-time guidance. The peripheral zone (PZ) of the prostate gland was defined as the clinical target volume (CTV) and the minimum prescribed dose to the CTV was 137 Gy. The volumes of the PZ, transition zone (TZ), and total prostate gland volume were also determined by MR. Individual source strength ranged from 0.35 to 0.54 microGym(2)/h (NIST 99, median 0.46 microGym(2)/h) and the total implanted activity ranged from 17.0 to 43.1 mCi (median, 28.1 mCi) using 43-120 seeds (median, 79). The seeds were placed using MR-compatible biopsy needles (14-28, median, 19).

RESULTS

The ability of clinical (MR defined prostate, PZ, and TZ volumes) and technical (number of catheters, number of seeds implanted, and total activity) factors to predict AUR for 50 men undergoing MR-guided prostate interstitial brachytherapy were evaluated using univariable and logistic regression multivariable analyses. Six men (12%) experienced AUR within 24 h after removal of the Foley catheter subsequent to prostate brachytherapy. The total number of seeds (p = 0.05), MR determined prostate volume (p < 0.01), and the MR-determined TZ volume (p < 0.01) were significant predictors of AUR on univariable analysis. Utilizing a multivariable logistic regression analysis, the TZ volume was the only significant predictor of AUR (p < 0.01). The prostate volume is highly correlated to the TZ volume (Spearman correlation coefficient of 0. 91) and was thus significant in the univariable analysis; however, the prostate volume did not add prognostic value in multivariable analysis.

CONCLUSION

Benign prostatic hyperplasia (BPH) resulting in an enlarged TZ volume, is the most important predictor of AUR following MR-guided prostate interstitial radiation therapy. Although AUR was significant (60%) in men with moderate BPH (TZ volume >/= 50 cc), it was also self-limiting.

Three-dimensional real-time magnetic resonance-guided interstitial prostate brachytherapy optimizes radiation dose distribution resulting in a favorable acute side effect profile in patients with clinically localized prostate cancer

PURPOSE

A large number of men are diagnosed with early-stage prostate cancer as a result of prostate-specific antigen (PSA) screening. For many of these men, prostatectomy results in long-term freedom from biochemical and clinical failure. Despite limited follow-up data, ultrasound-guided prostate brachytherapy has gained acceptance as a treatment for early-stage prostate cancer, in part due to its favorable side effect profile and brief recovery period. We report on the use of three-dimensional real-time magnetic resonance (MR) guidance, which has several advantages compared with biplanar ultrasound guidance for prostate brachytherapy, including enhanced geometric and dosimetric feedback during the procedure.

MATERIALS AND METHODS

Median clinical target volume coverage of 96% was achieved using MR guidance. The ability to define more precisely the clinical target volume with MR and the use of real-time assessment of dose distribution resulted in an excellent acute side effect profile. Only 19% of patients required oral alpha1 blockers for postimplant urethritis and 9% required temporary reinsertion of the Foley catheter due to acute urinary obstruction.

CONCLUSIONS

These results compare favorably to those of ultrasound-guided brachytherapy. Further follow-up is needed to ascertain the impact this technique will have on cancer control and long-term quality of life.

Staging of advanced ovarian cancer: comparison of imaging modalities--report from the Radiological Diagnostic Oncology Group

PURPOSE

To compare ultrasonography (US), magnetic resonance (MR) imaging, and computed tomography (CT) for diagnosing and staging advanced ovarian cancer.

MATERIALS AND METHODS

US, CT, and MR imaging were performed in 280 patients. Images were read by three radiologists from each of the five hospitals. Image analysis included determination of malignancy within the peritoneum (11 sites), lymph nodes (10 sites), and hepatic parenchyma. The standard of reference was based on surgical and histopathologic findings. Statistical methods used were receiver operating characteristic (ROC) curve analysis, pairwise comparison of areas under the ROC curves (A(z)), analysis of sensitivity and specificity pairs, and assessment of agreement between the degree of suspicion and standard of reference.

RESULTS

There were 118 patients with malignant tumors; 73 (62%) had stage III or IV disease. Metastases were found in the peritoneum in 70 (59%), nodes in 20 (17%), and liver in seven (6%) cases. In the peritoneum, MR imaging and CT (A(z) = 0.96 for both) were more accurate than US (A(z) = 0.86), especially in the subdiaphragmatic spaces and hepatic surfaces. MR imaging and CT were more sensitive than US (95%, 92%, and 69%, respectively) for peritoneal metastases. MR imaging was more accurate than CT for detection of lymph node metastases (A(z) = 0.76 vs 0.57, P =.04). In the liver, the A(z) values for the three modalities were 0.77-0.94.

CONCLUSION

CT and MR imaging are equally accurate, and either modality can be used to stage advanced ovarian cancer.

Real-time magnetic resonance imaging-guided brachytherapy in the treatment of selected patients with clinically localized prostate cancer

BACKGROUND AND PURPOSE

A real-time three-dimensional magnetic resonance imaging (MRI)-guided implant technique has been designed and implemented. This report summarizes the dosimetry achieved and the acute morbidity in the first patients.

PATIENTS AND METHODS

To date, 43 patients with clinical stage T(1c)N(X)M(0) prostate cancer, serum prostate specific antigen <10 ng/mL, and biopsy Gleason score no higher than 3 + 4 have been treated. The procedure was performed using an open magnet, with axial T1-weighted and fast spin echo images. The prescribed minimum radiation dose to the peripheral zone was 160 Gy. The total activity implanted ranged from 18.8 to 47.5 mCi using 43 to 120 (median 80) (125)I seeds. Dosimetric analyses were performed intraoperatively in real time for the tumor, anterior rectal wall, and prostatic urethra.

RESULTS

The percent of the clinical target volume receiving the prescription dose was 89% to 99% (median 96%). Using a conservative estimate of 164 Gy, no more than 9% of the urethral volume exceeded the tolerated dose. Using an estimated tolerated dose of 82 Gy, 30% to 100% (median 68%) of the anterior rectal wall volume was within the dose limit. Thirty-nine patients voided spontaneously within 3 hours of Foley catheter discontinuation, although four patients required recatheterization for a period. No patient reported gastrointestinal or sexual dysfunction during the first postoperative month.

CONCLUSION

A real-time MR-guided technique can achieve a minimum of 89% coverage of the tumor volume while maintaining the prostatic urethra and most of the anterior rectal wall below tolerance levels. Acute morbidity was minimal. Further follow-up is needed to ascertain the impact on cancer control and quality of life.

A clinical method for real-time dosimetric guidance of transperineal 125I prostate implants using interventional magnetic resonance imaging

PURPOSE

The clinical utility of an interventional magnetic resonance (IMR)-guided implant technique with real-time dosimetric feedback is presented.

METHODS AND MATERIALS

The work was carried out at a IMR unit at Brigham and Women's Hospital. Planning and dosimetric feedback were provided by a software system that provides an interface to the IMR images, anatomy demarcation, template registration, dose calculation engine for planning, and evaluating the implant. Planning during the procedure permits the incorporation of actual needle trajectories in the dose calculations.

RESULTS

Fifteen patients were planned in the treatment position. During source placement, actual needle locations were incorporated into the dose calculations. After accounting for the observed needle trajectories of the planned needles, 14 of 15 patients (93%) required additional sources to achieve the desired coverage of the target volume.

CONCLUSION

A brachytherapy implant procedure which provides clinically significant advances has been implemented. Specifically, the planning system allows dosimetric validation of the needle placement. This procedure is effective in delivering brachytherapy to the target volume and assuring that the implant is delivered in accordance with the preplan. The dosimetric feedback could be incorporated in ultrasound-guided implants.

Diagnosis and staging of ovarian cancer: comparative values of Doppler and conventional US, CT, and MR imaging correlated with surgery and histopathologic analysis--report of the Radiology Diagnostic Oncology Group

PURPOSE

To determine the optimal imaging modality for diagnosis and staging of ovarian cancer.

MATERIALS AND METHODS

Two hundred eighty women suspected to have ovarian cancer were enrolled in a prospective study before surgery. Doppler ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging were used to evaluate the mass; conventional US, CT, and MR imaging were used to stage spread.

RESULTS

All three modalities had high accuracy (0.91) for the overall diagnosis of malignancy. In the ovaries, the accuracy of MR imaging (0.91) was higher than that of CT and significantly higher than that of Doppler US (0.78). In the extraovarian pelvis and in the abdomen, conventional US, CT, and MR imaging had similar accuracies (0.87-0.95). In differentiation of disease confined to the pelvis from abdominal spread, the specificity of conventional US (96%) was higher than that of CT and significantly higher than that of MR imaging (88%), whereas the sensitivities of MR imaging (98%) and CT (92%) were significantly higher than that of conventional US (75%).

CONCLUSION

MR imaging is superior to Doppler US and CT in diagnosis of malignant ovarian masses. There is little variation among conventional US, CT, and MR imaging as regards staging.

Original smooth receiver operating characteristic curve estimation from continuous data: statistical methods for analyzing the predictive value of spiral CT of ureteral stones

RATIONALE AND OBJECTIVES

Diagnostic studies such as spiral computed tomography (CT) in patients with obstructing ureteral calculi often necessitate the analysis of continuous test data (e.g., stone sizes). The accuracy of a test can be summarized by using a receiver operating characteristic (ROC) curve. The authors developed and compared three methods for constructing a smooth ROC curve from continuous diagnostic data.

MATERIALS AND METHODS

Nonparametric, semiparametric, and parametric smooth ROC curve analyses were applied to data from 100 unenhanced spiral CT scans of patients with proved obstructing ureteral stones. Accuracy in using stone size to predict the need for intervention was evaluated by means of these methods. Characteristics and summary measures of the resulting ROC curves were estimated.

RESULTS

All methods fit the data well. The nonparametric method followed the details of the empiric data. The semiparametric and parametric methods yielded similar estimates of the ROC curve parameters. Areas under the ROC curves were 0.807, 0.821, and 0.814 for nonparametric, semiparametric, and parametric methods, respectively, in comparison with 0.811 for the empiric method.

CONCLUSION

The parametric method is preferred for constructing a smooth ROC curve with available stone-size data derived from spiral CT. The analyses confirm the predictive value of stone size in determining the need for intervention.

Real-time magnetic resonance image-guided interstitial brachytherapy in the treatment of select patients with clinically localized prostate cancer

PURPOSE

This study was performed to establish the dose-localization capability and acute toxicity of a real-time intraoperative magnetic resonance (MR) image-guided approach to prostate brachytherapy in select patients with clinically localized prostate cancer.

METHODS AND MATERIALS

Nine patients with 1997 American Joint Commission on Cancer (AJCC) clinical stage T1cNxM0 prostate cancer, prostate-specific antigen (PSA) < 10 ng/ml, biopsy Gleason score not exceeding 3 + 4, and endorectal coil MR stage T2 disease were enrolled into this study. The prescribed minimum peripheral dose was 160 Gy to the clinical target volume (CTV), which was the MR-defined peripheral zone (PZ) of the prostate gland. Using a real-time 0.5 Tesla intraoperative MR imaging unit, 5-mm image planes were obtained throughout the prostate gland. The PZ of the prostate gland, anterior rectal wall, and prostatic urethra were identified on the T2 weighted axial images by an MR radiologist. An optimized treatment plan for catheter insertion was generated intraoperatively. Each catheter containing the 125Iodine sources was placed under real-time MR guidance to ensure that its position in the coronal, sagittal, and axial planes was in agreement with the planned trajectory. Real-time dose- volume histogram analyses were used intraoperatively to optimize the dosimetry.

RESULTS

For the 9 study patients, 89-99% (median 94%) of the CTV received a minimum peripheral dose of 160 Gy and > or = 95% of the volume of the prostatic urethra and 42-89% (median 70%) of the volume of the anterior rectal wall received doses that were below the reported tolerance. All patients voided spontaneously within 3 h after discontinuation of the Foley catheter and no patient required more than a limited course (< or = 3 weeks) of oral alpha-1 blockers for postimplant urethritis.

CONCLUSIONS

Real-time MR-guided interstitial radiation therapy provided the ability to achieve the planned optimized dose-volume histogram profiles to the CTV and healthy juxtaposed structures intraoperatively, with minimal acute morbidity.

MR imaging of the prostate and bladder

Magnetic resonance imaging has become an important imaging modality for the male pelvis. Its unparalleled ability to depict soft tissue structures and highlight pathology have made it the best method for determining the extent of many disease processes. This article reviews the use of MR to evaluate diseases of the prostate gland and bladder. In both, the major indication for imaging is the local staging of cancer, and MR is currently the best imaging modality. This article will discuss the critical clinical issues concerning prostate cancer and neoplasms of the bladder, and the contribution of MR imaging.

Open-configuration MR imaging, intervention, and surgery of the urinary tract

The open-configuration MR imaging system provides new applications both in diagnosis and in therapy of conditions in the urinary tract. In addition to conventional imaging, the open configuration permits MR imaging of patients in many positions. This has already been shown to be useful in imaging the pelvis during voiding, where a sitting position allows urodynamic evaluation. The lithotomy position can be used for imaging the prostate, which also permits procedural access. The ultimate purpose of the interventional MR imaging suite is to integrate therapeutic tools and techniques with MR imaging. From surgical planning through specialized imaging systems with minimally invasive surgical applications, new methods are being developed and implemented. This new field of image-guided therapy will require extensive clinical development and evaluation for applications in the urinary tract. This will require a large concentrated interdisciplinary effort of surgeons, radiologists, computer scientists, engineers, and physicists. Successful integration of basic research and clinical work will result in a number of cutting-edge technologies with direct clinical application in the urinary tract. Initial projects have included biopsies, endoscopies, and real-time procedural control of high-temperature and cryogenic ablations. It is anticipated that the current surge in image-guided interventions will motivate even more research activity in this field, and will ultimately define the role of MR imaging guidance in urologic intervention and surgery.

Assessment of prostate cancer volume using endorectal coil magnetic resonance imaging: a new predictor of tumor response to neoadjuvant androgen suppression therapy

OBJECTIVES

A clinical tool that can reliably assess prostate cancer response to androgen suppression is lacking. This pilot study was designed to identify the potential clinical factor(s) that correlate with tumor response after neoadjuvant therapy.

METHODS

Twenty-one patients managed with definitive local therapy and neoadjuvant androgen suppression (median 3 months [range 2 to 7]) between 1995 and 1997 comprise the study population. Fisher's exact test was used to test the significance of the proportion of patients with a given clinical factor and the outcome of pathologic organ-confined disease. The clinical factors tested included preoperative prostate-specific antigen, biopsy Gleason score, clinical stage, months of total androgen suppression, the change in the endorectal magnetic resonance imaging (erMRI)-defined stage, the change in erMRI-defined tumor, and the change in the erMRI-defined prostate volume during neoadjuvant androgen suppression.

RESULTS

All 21 patients had a decrease in the erMRI-determined prostate volume and prostate-specific antigen during androgen suppression, whereas only 10 of 21 (48%) had a reduction in the erMRI-determined tumor volume. There was a statistically significant increased proportion of patients with a decrease in the erMRI-determined tumor volume (P = 0.008) who had pathologic organ-confined disease.

CONCLUSIONS

The results of this pilot study suggest that the changes in the erMRI-determined tumor volume occurring during androgen suppression may be predictive of the tumor response. Validation in a larger prospective study is currently underway.

Prostate cancer: relative effects of demographic, clinical, histologic, and MR imaging variables on the accuracy of staging

PURPOSE

To determine the effects on the accuracy of staging prostate gland cancer of diagnostic prediction rules based on demographic, clinical, histologic, and magnetic resonance (MR) image variables.

MATERIALS AND METHODS

A total of 200 cases from four medical centers were evaluated by nine radiologists experienced in MR imaging. The accuracies of the four diagnostic variables (age, prostate specific antigen level, Gleason tumor grade, and MR imaging findings) were measured, both singly and combined in a particular sequence, by calculating the area index of the receiver operating characteristic curve.

RESULTS

The accuracy of staging with single variables (age, 0.58; prostate specific antigen level, 0.74; Gleason grade 0.73, MR image findings, 0.74) increased as the variables were optimally merged. The first two variables combined to yield an accuracy of 0.74; the first three combined to yield an accuracy of 0.81; and all four variables resulted in an accuracy of 0.86. In a clinically important subset of 69 cases for which antigen level and Gleason grade together were inconclusive for the purposes of staging, the addition of MR imaging findings resulted in an increase in accuracy from 0.55 to 0.73.

CONCLUSION

Optimal merging of diagnostic test results yields an improvement in the accuracy of prostate cancer staging.

Spiral CT in the evaluation of flank pain: overall accuracy and feature analysis

PURPOSE

Our goal was to assess test reliability and identify those features that have the strongest positive and negative predictive values in the diagnosis of renal colic using spiral CT.

METHOD

Fifty non-contrast-enhanced CT scans (5 mm slice thickness) obtained in patients presenting with flank pain were reviewed by three radiologists blinded to the final diagnoses. The sensitivity, specificity, and positive and negative predictive values for nine pertinent findings were determined as compared to clinical follow-up.

RESULTS

Twenty-nine cases had findings of ureteral obstruction. Findings with the strongest positive predictive values (> 0.90) were ureteral stone, hydronephrosis, hydroureter, periureteral stranding, and ureterovesical junction edema. Findings with the strongest negative predictive values (> 0.89) were absence of hydronephrosis and hydroureter. The areas under the receiver operating curves for Readers 1, 2, and 3 were 0.970 +/- 0.030, 0.942 +/- 0.036, and 0.982 +/- 0.020.

CONCLUSION

Absence of hydroureter and hydronephrosis on spiral CT images should prompt a search for a diagnosis other than an obstructing ureteral stone.

MR hysterography using axial long TR imaging with three-dimensional projections of the uterus

A rapid screening technique for the presentation of uterine cavity anatomy obtained with MR is described. MR hysterographic (MRHG) images were generated and evaluated for uterine cavity abnormalities. Six patients referred for MRI evaluation of the uterus for infertility had an MRI using a pelvic phased array coil with axial 3 mm interleaved fast spin echo images (TR 9000 ms, TE 288 ms with fat saturation) processed using maximum intensity projection algorithms to construct MRHG images. Using the conventional MR sequence as the gold standard the MRHG images were evaluated by two reviewers and accuracy calculated. MRHG took less than 3 min, demonstrated the correct diagnosis in all with a quality score of diagnostic to optimal, and with excellent interobserver agreement (kappa 0.9).

Staging prostate cancer with MR imaging: a combined radiologist-computer system

PURPOSE

To test the accuracy of a combined radiologist-computer system in the diagnosis with magnetic resonance (MR) imaging of cancer of the prostate gland.

MATERIALS AND METHODS

The combined system was developed and tested by four specialists in prostate MR imaging and five radiologists expert in body MR imaging. Each group read MR images obtained in 100 proved cases of prostate cancer. The images were obtained from two sources, and all were obtained with an endorectal surface coil. Prostate MR specialists ranked imaging features of cases to develop a checklist for image interpretation. Features with greatest diagnostic value were incorporated in the combined system. Accuracy measures were derived from the area index of the receiver operating characteristic curve for the combined system and compared with those of radiologists working alone.

RESULTS

Body MR radiologists had a mean baseline accuracy of 0.67; mean accuracy of their combined system was 0.80. The prostate MR specialists, when they rated the features in each case, had a mean accuracy of 0.81; the accuracy of their combined system was 0.87.

CONCLUSIONS

A combined radiologist-computer system substantially improved accuracy of body MR radiologists in the diagnosis of prostate cancer. High levels of accuracy were also achieved by the system with prostate MR specialists.

Small (< or = 3 cm) hyperechoic renal masses: comparison of helical and convention CT for diagnosing angiomyolipoma

OBJECTIVE

Because hyperechoic renal masses may represent angiomyolipomas or small renal cancers, CT is often used to reveal the fatty component, which allows diagnosis of angiomyolipoma in most cases. Because conventional CT can fail to reveal fat in angiomyolipomas 3 cm or smaller, we conducted a study to determine whether helical CT would improve our detection of fat and allow more of these masses to be diagnosed as angiomyolipomas.

SUBJECTS AND METHODS

We used helical and conventional CT to examine 20 masses (5-29 mm in diameter) in 17 patients who had a small hyperechoic mass detected sonographically. Densitometry was performed by three readers and the mean attenuation values were compared.

RESULTS

Of the 20 masses, we diagnosed angiomyolipoma in 16 masses using helical CT and in 14 masses using conventional CT. In 11 masses, we found the measured attenuation values to be more negative on helical CT scans than on conventional CT scans. In five masses, we found the opposite to be true. In the remaining four masses, we were unable to diagnose angiomyolipoma. Of the masses that we diagnosed as angiomyolipoma, the mean attenuation value when examined with helical CT (-44 H) was more negative than with conventional CT (-35 H) but not significantly so (p = .058). However, in the subset of patients with masses that were 2 cm or less in diameter (n = 14), the mean attenuation values on helical CT were significantly lower than on conventional CT (-40 H versus -30 H, p < .05). Likewise, for masses with attenuation values that differed by more than 6 H (n = 8), when imaged by the two techniques we again found that mean attenuation values on helical CT were significantly lower (-43 H versus -24 H, p < .05).

CONCLUSION

Helical CT revealed angiomyolipoma across all cases as well as conventional CT did. Also, helical CT was more sensitive in revealing fat in masses less than 2 cm in diameter and in masses in which the attenuations of the two CT techniques differed by a significant amount. We preferred helical CT over conventional CT when examining hyperechoic masses for the purpose of diagnosing angiomyolipoma.

CT and MR imaging in the staging of colorectal carcinoma: report of the Radiology Diagnostic Oncology Group II

PURPOSE

To prospectively evaluate the relative accuracy of computed tomography (CT) and magnetic resonance (MR) imaging in the staging of colorectal carcinoma.

MATERIALS AND METHODS

CT and MR studies were independently interpreted in a group of 478 patients with colorectal carcinoma in a study conducted from 1989 to 1993. The accuracy of each modality was assessed in a subset of 365 patients with primary tumors with respect to staging of local extent of tumor, status of local-regional lymph nodes, and the presence of liver metastases.

RESULTS

In the staging of local extent of tumor, CT is more accurate than MR imaging, particularly in the definition of penetration of the muscularis propria by rectal cancer (74% vs 58%). Accuracies of CT and MR imaging were equivalent in depiction of transmural extent in colon cancers. CT and MR imaging exhibited accuracies of 62% and 64% in assessment of lymph node involvement with sensitivities of 48% and 22%, respectively. The accuracy of MR imaging and of CT (85% for each) are better for evaluation of liver metastases; lower sensitivities (62% and 70%, respectively) than specificities (97% and 94%, respectively) were demonstrated for both modalities.

CONCLUSION

CT was more accurate than MR imaging in detection and characterization of transmural penetration of rectal tumors. Recent technologic advances in MR imaging may affect these results.

MR staging of prostate cancer. How we can improve our accuracy with decisions aids and optimal techniques

This article reviews the MR staging of prostate cancer. There has been considerable variability in the MR results to date. The reasons are complex and include reader experience, the learning curve, and a lack of clear definition of the diagnostic features of advanced disease. The problems associated with achieving a consistently high degree of accuracy are discussed. The author describes a new study aimed at improving radiologists accuracy and illustrates some of the findings and specific features of advanced disease that are useful.

An analysis of the time course of postoperative prostate-specific antigen failure in patients with positive surgical margins: implications on the use of adjuvant therapy

OBJECTIVES

The role of adjuvant therapy in the postprostatectomy setting for positive margin patients is an unresolved issue. The purpose of this study is to provide the rationale for patient selection in Phase III trials that test the impact of adjuvant therapy on survival in positive margin prostate cancer patients.

METHODS

Early (12 months or less) and delayed (more than 12 months) postoperative prostate-specific antigen (PSA) failure have been correlated with distant and local failure, respectively, as the site of first failure. In this study, a Cox regression multivariate analysis was used to determine the significant independent clinical and pathologic predictors of early and delayed postoperative PSA failure in 143 margin-positive prostate cancer patients.

RESULTS

Margin-positive patients with positive pelvic lymph nodes, seminal vesicle invasion, or prostatectomy Gleason sum 8 or higher were excluded. For the remaining patients, a prostatectomy Gleason sum of 7, preoperative PSA more than 20 ng/mL, and an endorectal coil magnetic resonance imaging (erMRI) scan showing extensive disease were significant independent predictors of early postoperative PSA failure. Conversely, a prostatectomy Gleason sum of 6 or less, preoperative PSA 20 ng/mL or less, and an erMRI showing limited disease predicted delayed PSA failure.

CONCLUSIONS

Preliminary data suggest that the pattern of first failure can be predicted by the time course of rise in the postoperative PSA. The preliminary results of this study suggest that patient selection for clinical trials examining the efficacy of postoperative adjuvant therapy in the positive margin patient may be determined on the basis of the clinical and pathologic characteristics that predict early versus delayed postoperative PSA failure.

Effect of slice acquisition direction on image quality in thoracic MRI

OBJECTIVE

We tested the basic observation that imaging the heart and pericardium in systole improves image quality compared with that in diastole.

MATERIALS AND METHODS

Twenty consecutive patients and two volunteers underwent sequential ECG-gated short TE transaxial prospective multislice SE MRI with both caudocranially and craniocaudally directed slice prescriptions, keeping other imaging parameters constant. Images of the heart and pericardium were obtained in systole and diastole and examined by three independent reviewers for image quality.

RESULTS

In the lower mediastinum, cardiac structures and the pericardium were better seen in 49 of 57 individual evaluations when imaged in systole, 15 of which were judged markedly better. Vascular structures and the pericardium in the upper mediastinum were imaged equally well with both prescriptions.

CONCLUSION

The findings suggest that in systole, the more mobile heart can maintain a more consistent shape during the acquisition of successive phase-encoding steps and preserve luminal flow void, factors critical to optimizing image quality in the transaxial plane.

Second trimester uterine atony imitating ectopic pregnancy: magnetic resonance diagnosis

When an obstetrical patient was referred for inability to auscultate fetal heart tones at 18 weeks' gestation, ultrasound identified a single living fetus in the maternal right upper quadrant. Magnetic resonance imaging (MRI) ruled out a suspected uterine ectopic pregnancy and avoided laparotomy. The patient experienced an uncomplicated term delivery. MRI is a useful adjunct to ultrasound for mid-trimester pregnancy localization when the differential diagnosis includes uterine eccyesis.

Superparamagnetic iron oxide hepatic MR imaging: efficacy and safety using conventional and fast spin-echo pulse sequences

The purpose of this study was to evaluate the technical efficacy and safety of iv ferumoxides (Feridex), a superparamagnetic iron oxide contrast agent for detection of hepatic lesions using conventional spin-echo and fast spin-echo MR images. Precontrast and postcontrast MR studies were performed on 25 patients with suspected focal hepatic lesions. Conventional T1- and T2-weighted MR images, as well as fast spin-echo and fat suppressed fast spin-echo MR images, were evaluated. Quantitative assessment of the contrast agent was performed obtaining region of interest measurements of the liver, spleen, and selected hepatic lesions. The pulse sequences were also evaluated subjectively for overall image quality and a subjective assessment of lesion detection. The use of a superparamagnetic iron oxide contrast agent led to a decrease in hepatic signal intensity on all pulse sequences. Lesion-to-liver contrast increased 41.1%, 36.5%, and 32.0% on the conventional T2, fast spin-echo, and fat suppressed fast spin echo pulse sequences, respectively. Lesion-to-liver contrast decreased on the T1-weighted postcontrast pulse sequence by 23.8%. Despite improvement in lesion-to-liver contrast, radiologists subjectively preferred the precontrast sequences because of overall better image quality. At a dose of 10 mumol/kg, ferumoxides favorably impacts lesion-to-liver contrast, and may be useful in hepatic imaging, more with conventional T2-weighted spin-echo pulse sequences than with T2-weighted fast spin-echo pulse sequence.

Thrombophlebitic retroperitoneal collateral veins mimicking lymphadenopathy: MR and CT appearance

The authors report the magnetic resonance (MR) and computed tomography (CT) features of what is believed to be thrombophlebitis of the left cava of a duplicated IVC, which mimicked lymphadenopathy, and prompted both a CT-guided needle aspiration biopsy and surgical exploration. Knowledge that retroperitoneal vascular anomalies can mimick lymphadenopathy, both clinically and radiographically, may help obviate further testing and intervention.

The use of dynamic magnetic resonance imaging to evaluate orthotopic continent urinary diversion

OBJECTIVES

The purpose of this study was to evaluate a dynamic magnetic resonance (MR) examination in patients after radical cystoprostatectomy with a neobladder.

METHODS

All 12 subjects were studied with the injection of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) and showed normal renal enhancement patterns and upper urinary tracts, except 1 patient who had mild right hydronephrosis. All neobladders were also visualized with gadolinium and 9 of 11 patients were able to void on command. There was close agreement in all cases with the MR findings and other imaging studies.

RESULTS

A static and dynamic Gd-DTPA contrast medium MR did image the entire urinary system, similar to a computed tomographic scan or intravenous urogram. Renal function data, similar to a renal radioisotope scan, was obtained from the Gd-DTPA scans. A dynamic voiding study provided visualization of the lower genitourinary tract similar to a conventional voiding cystourethrogram.

CONCLUSIONS

We conclude that this single MR technique may provide information similar to that obtained from multiple standard imaging studies in the postoperative assessment of the radical cystectomy patient with a neobladder. It may be especially helpful in the presence of azotemia or contrast allergy.

Evaluation of erectile function in men with sickle cell disease

OBJECTIVES

To evaluate and characterize erectile manifestations associated with sickle cell disease using nocturnal penile tumescence testing with polysomnography (NPT/PSG) and magnetic resonance imaging (MRI) of the penis.

METHODS

Six variably potent men with sickle cell disease, of whom 5 reported a history of priapism, underwent comprehensive evaluations of erectile function. Evaluations involved a medical history and physical examination with completion of priapism and sexual function questionnaires, followed by NPT/PSG and MRI of the penis.

RESULTS

Many different erectile abnormalities were identified in this group using NPT/PSG, although nocturnal erection durations as well as detumescence times were uniformly prolonged. Various axial rigidity measurements were obtained, which correlated fairly well with individual reports of erectile function. MRI findings ranged from normal corporeal anatomy to corporeal destruction with intracorporeal fibrosis and hemosiderin deposition.

CONCLUSIONS

In sickle cell disease, the erectile dysfunction that commonly occurs may be markedly different among men with this disease and may not always be predicted on the basis of clinical history of priapism. Generally, clinical assessments of erectile function may be derived from clinical histories and physical examinations. NPT/PSG and MRI of the penis are in accord with these assessments, obviating their routine use, although they may be valuable management adjuncts in certain situations.

Staging of prostate cancer: results of Radiology Diagnostic Oncology Group project comparison of three MR imaging techniques

PURPOSE

To assess accuracy of three different magnetic resonance (MR) imaging techniques, including the endorectal coil, in staging prostate cancer.

MATERIALS AND METHODS

MR imaging was performed in 213 patients with prostate cancer with a conventional body coil, with fat suppression and a body coil, and with an endorectal coil. Radiologists identified tumor invasion into periprostatic tissues, neurovascular bundles, and seminal vesicles. Each technique was evaluated separately, and in a subset of 74 patients the three techniques were evaluated together. Images obtained with the two body-coil techniques were read in combination with images obtained with the endorectal coil (combination A) and alone (combination B).

RESULTS

Overall accuracy for conventional body-coil, fat-suppressed body-coil, and endorectal-coil MR was 61%, 64%, and 54%, respectively. Overall group accuracy for combinations A and B was 57% and 61%. Considerable interreader variability was found for combination A.

CONCLUSION

No technique was highly accurate for staging early prostate cancer. Individual radiologists did achieve a high degree of staging accuracy with the endorectal-coil and body-coil combination.

Prospective comparison of T2-weighted fast spin-echo, with and without fat suppression, and conventional spin-echo pulse sequences in the upper abdomen

PURPOSE

To evaluate use of fast spin-echo (FSE) magnetic resonance imaging with and without fat suppression in the liver and upper abdomen.

MATERIALS AND METHODS

Conventional spin-echo (SE) T2-weighted, FSE T2-weighted, and fat-suppressed FSE T2-weighted images from 37 patients strongly suspected to have focal hepatic lesions were evaluated.

RESULTS

Quantitative analysis demonstrated that fat-suppressed FSE imaging had the highest lesion-liver contrast-to-noise ratio; conventional SE imaging, the lowest. In a qualitative analysis, FSE imaging was preferred. In a rank order analysis, FSE imaging was preferred 83% of the time and fat-suppressed FSE imaging 17% of the time as regards overall image quality; fat-suppressed FSE imaging was preferred 64% of the time, FSE imaging 23% of the time, and conventional SE imaging 13% of the time as regards signal abnormality detection.

CONCLUSION

FSE imaging with and without fat suppression is a potentially useful pulse sequence for evaluating the upper abdomen.

The influence of finasteride on the volume of the peripheral and periurethral zones of the prostate in men with benign prostatic hyperplasia

To determine the influence of androgen deprivation induced by the potent 5 alpha-reductase inhibitor finasteride on the volume of the zones of the prostate, 20 symptomatic men with established BPH were randomized to one of three groups: placebo, finasteride 1 mg, and finasteride 5 mg/day. The volume of the entire prostate gland, periurethral zone, and peripheral zone and the seminal vesicles were determined by three dimensional reconstructions of magnetic resonance contoured images of the prostate. There was no significant difference between the results achieved with 1 and 5 mg of finasteride per day; thus the results in these two groups were combined. In the placebo group there was no significant change in the volume of any structure. Following treatment for 1 year with finasteride there was a significant (P < 0.02) 17% decrease in total gland size (11.5 +/- 3.2 cc). Similarly, there was a significant (P < 0.02) 17% decrease in total gland size (11.5 +/- 3.2 cc). Similarly, there was a significant (P < 0.03) decrease in the size of the periurethral zone of the prostate (6.2 +/- 3 cc). Although there was also a decrease in the size of the peripheral zone of the prostate (2.8 +/- 1.2 cc) this did not reach statistical significance. There was no significant change in the volume of the seminal vesicles. These findings indicate for the first time that androgen deprivation induces a significant decrease in the size of the periurethral zone of the prostate in men with established BPH.