Magnetic resonance.
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Echo-Planar Imaging↗
Biomedical subjects
H Hricak
Publications and source records attributed to H Hricak.
Bladder tumor staging: comparison of contrast-enhanced CT, T1- and T2-weighted MR imaging, dynamic gadolinium-enhanced imaging, and late gadolinium-enhanced imaging.
PURPOSE: To evaluate the accuracy of contrast material-enhanced computed tomography (CT), unenhanced T1- and T2-weighted magnetic resonance (MR) imaging, and dynamic gadolinium-enhanced spoiled gradient-echo MR imaging in the staging of bladder cancer. MATERIALS AND METHODS: Thirty-six patients with histologically proved bladder cancer were prospectively examined with CT and MR imaging before tumor resection. Images were evaluated in a blinded fashion. RESULTS: All methods depicted tumors comparably well. Staging was correct in 16 of 29 patients (55%) with CT and 27 of 36 patients (75%) overall with MR imaging. Overstaging was the most common error, and both CT and MR imaging were more accurate for higher-staged tumors. CONCLUSION: CT and MR imaging perform well in the detection of tumors but are less accurate in staging. Dynamic gadolinium-enhanced MR imaging is better than other techniques, but the difference is not statistically significant.
Carcinoma, Transitional Cell↗
Carcinoma of the prostate gland: MR imaging with pelvic phased-array coils versus integrated endorectal--pelvic phased-array coils.
PURPOSE: To compare the performance of pelvic phased-array (PPA) coils and integrated endorectal PPA coils in evaluation of local extent of prostate cancer. MATERIALS AND METHODS: Seventy-one men underwent magnetic resonance (MR) imaging within 3 weeks of radical prostatectomy. MR findings of tumor, extracapsular extension, seminal vesicle invasion, nodal involvement, and stage were compared with step-sectioned (3-4-mm intervals) whole-mounted pathologic specimens. Prospective consensus versus single-reader interpretation (kappa statistics) and PPA versus integrated endorectal PPA coils (McNemar test) were compared, and a rating scale of 1-6 was developed for analysis of receiver operating characteristics. Statistical significance was calculated at delta = .05. RESULTS: Comparison between consensus and single-reader image interpretation showed positive but poor agreement (kappa = .38) and no statistical significance. Staging accuracy was better (difference approached significance) for integrated endorectal PPA coils (77%) than for PPA coils (68%). CONCLUSION: The integrated endorectal PPA coil is better for evaluation of local prostatic cancer than is the PPA coil.
Humans↗
Staging accuracy of magnetic resonance imaging versus transrectal ultrasound in stages A and B prostatic cancer.
The present study was undertaken to compare the ability of magnetic resonance imaging (MRI) and transrectal ultrasound (TRUS) to identify the presence or absence of extracapsular tumor extension and seminal vesicle involvement in patients with clinically localized (stages A and B, T1-T2) prostatic cancer. Sixty-four patients (ages 44-77 years) underwent radical retropubic prostatectomy and pelvic lymphadenectomy after staging with both MRI and TRUS. Surgical specimens were step-sectioned and examined at multiple levels. Radiographic staging was correlated with pathological staging. Both MRI and TRUS demonstrated better staging accuracy than conventional digital rectal examination [42% for digital rectal examination (DRE), 63% by TRUS, and 67% by MRI], although they suffered from understaging (31% by TRUS and 22% by MRI). The positive predictive value (PPV) for stage B disease was disappointingly low (42% for DRE, 53% for TRUS and 59% for MRI). However, the PPV for stage C disease was higher (81% for TRUS and 77% for MRI). In the evaluation of extracapsular invasion, the PPV of TRUS (81%) was higher than that of MRI (77%). The negative predictive value (NPV), however, for both TRUS and MRI was low (58 and 56%, respectively). In the evaluation of seminal vesicle invasion, both TRUS and MRI demonstrated poor PPV (50 and 40%, respectively), but the NPV was excellent (90% for TRUS and 96% for MRI). MRI failed to detect metastatic lymph nodes in 4 of 6 patients while falsely predicting their presence in 4 patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Congenital malformations of uterus and vagina.
Congenital malformations of uterus and vagina result from failure of development, failure of fusion or septal reabsorption of the Mullerian ducts. They present with a spectrum of findings ranging from agenesis to duplications. They are of clinical importance because of their association with menstrual disorders and impaired fertility. Furthermore, women with Mullerian duct anomalies (MDAs) have a significant risk of obstetric complications such as spontaneous abortion, stillbirth and preterm delivery. Hysterosalpingography (HSG) and laparoscopy have long played a pivotal role in the evaluation of MDAs. Ultrasonography and recently magnetic resonance imaging (MRI) have emerged as noninvasive modalities that are used complementarily or as alternative diagnostic tools. The radiographic findings according to the classification of Buttram and Gibbons are described for HSG, ultrasound and MRI. The advantages and limitations of each method are discussed, and finally an algorithm for imaging is recommended.
Diagnosis, Differential↗
Response to editorial by Dr. Maruyama.
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Female↗
Carcinoma of the cervix: predictive value of clinical and magnetic resonance (MR) imaging assessment of prognostic factors.
PURPOSE: This retrospective study assesses the predictive value of magnetic resonance imaging (MRI) to identify high risk cervical cancer patients. METHODS AND MATERIALS: The MRI evaluation of morphologic risk factors in patients with invasive cervical carcinoma treated with definitive radiation therapy were correlated with clinical factors and with complete tumor regression (CTR) at 6 months, tumor local control (TLC), and patient outcome at 12 months after irradiation. Sixty-six patients, median age 44.5 years, with bulky Stage I or greater disease were included in the study. RESULTS: In univariate analysis, clinical International Federation of Gynecology and Obstetrics (FIGO) stage had significant correlation with patient outcome, but it correlated poorly with complete tumor regression and tumor local control. In contrast, MRI stage showed significant correlation with complete tumor regression, tumor local control, and disease-free survival at 12 months. When each stage was analyzed separately, the greatest difference was demonstrated between clinical and MRI assignment of stage Ib disease. MRI Stage Ib disease significantly correlated with all three categories analyzed, while clinical Stage Ib did not. Superiority of MRI assessment of low stage disease was also evident in the detection of lymph node metastasis. Significant risk for nodal metastasis was related to tumor size greater than 4 cm, invasion of the parametria and urinary bladder, and stage of the disease. CONCLUSION: The multivariate analysis demonstrated that the most related variables in order of significance were the presence of juxta-regional and paraaortic lymph nodes, patient age, tumor size, and MRI tumor stage. This study demonstrates the value of MR imaging as an adjunct to clinical assessment of bulky invasive cervical cancer, rendering more complete assessment of morphologic risk factors important in patient prognosis.
Adult↗
Imaging in gynecologic malignancies.
Cross-sectional imaging is often a useful complement to clinical examination in patients with gynecologic malignancies. Patients with ovarian cancer will benefit less from the use of computed tomography and magnetic resonance imaging (MRI); however, extensive intraperitoneal disease may be evaluated and followed with either technology. Endometrial cancer is best approached by staging with contrast-enhanced MRI. The more advanced the disease is, the more information should be available from MRI imaging. By contrast, patients with cervical cancer are assessed best using noncontrast-enhanced MRI as far as imaging of the primary tumor is concerned. Extracervical extension is defined better with contrast enhancement and varied pulse sequences. Radiation changes and tumor response also can be assessed with MRI imaging as a complement to clinical examination.
Endometrial Neoplasms↗
Liver lesion detection: comparison between excitation-spoiling fat suppression and regular spin-echo at 1.5T.
The role of excitation-spoiling fat suppression (fatsat) imaging in the detection of liver lesions was assessed comparing short TR/TE and lont TR/TE spin-echo (SE) sequences with and without excitation-spoiling fat suppression in 25 patients at 1.5T. The study included patients with liver metastases (n = 21), primary liver cancer (n = 3), and hepatic adenoma (n = 1). Liver lesion detection and lesion-liver signal-to-noise ratios (SNR) were determined for the various imaging sequences in a prospective fashion. Liver lesion-liver SNR were highest for long TR/TE (2000-2500/70-80) fatsat images (12.7 +/- 4.8) compared to long TR/TE regular SE (2000-2500/70-80) images (8.8 +/- 5.6) [(p = ns) (not significant)], short TR/TE (200-400/15-20) fatsat images (-6.2 +/- 4.8) (p = 0.05), and short TR/TE regular SE images (-4.9 +/- 3.2) (p < 0.01). Lesion detection was greatest for long TR/TE fatsat (86) followed by long TR/TE regular SE (78) (p = 0.05), short TR/TE fatsat (65) (p < 0.01), and short TR/TE regular SE (60) (p < 0.01). The results of this study suggest that excitation-spoiling fat suppression may improve liver lesion detection and conspicuity.
Adolescent↗
Posttraumatic impotence: magnetic resonance imaging and duplex ultrasound in diagnosis and management.
In 15 patients, impotent as a result of prostatomembranous urethral disruption consequent to pelvic crush injuries, magnetic resonance imaging (MRI) and duplex ultrasound were used to establish anatomical and pathophysiological criteria for accurate diagnosis and appropriate management. All patients were initially treated by suprapubic cystostomy diversion for at least 3 months, after which urethral reconstruction was performed. All men were potent before the pelvic trauma, with loss of sexual function immediately thereafter. Preoperative MRI demonstrated prostatic displacement in 13 cases (86.7%) and cavernous injury in 12 (80%). Duplex ultrasound revealed the cause of erectile failure as vasculogenic in 12 patients (80%) and neurogenic in 3 (20%). Treatment of impotence was deferred for at least 18 months after injury. Of the neurogenic group 2 patients were started on intracavernous injection therapy and 1 refused treatment. Of the vasculogenic group 3 patients underwent successful revascularization, 2 are on injection therapy and 1 had a penile prosthesis inserted. The detailed anatomical information obtainable with pelvic MRI and the functional data provided by duplex ultrasonography enabled us to identify the individual organic components of posttraumatic impotence and to select effective cause-specific therapy.
Adolescent↗
Current trends in MR imaging of the female pelvis.
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Contrast Media↗
Teratomas versus cystic hemorrhagic adnexal lesions: differentiation with proton-selective fat-saturation MR imaging.
To assess the value of proton-selective fat-saturation magnetic resonance (MR) imaging in differentiating teratomas from cystic hemorrhagic masses, 38 patients with 48 lesions (21 teratomas, 27 cystic hemorrhagic masses) detected at prior ultrasound or computed tomography were imaged with standard T1- and T2-weighted spin-echo (SE) sequences. Twenty-one patients with 28 lesions (13 teratomas, 15 cystic hemorrhagic masses) were imaged with an additional T1-weighted fat-saturation sequence. On standard T1- and T2-weighted SE images, 43% of the teratomas and 52% of the cystic hemorrhagic masses were characterized correctly with signal intensity criteria. Sixty-two percent of the teratomas and 100% of the cystic hemorrhagic masses were characterized correctly with chemical shift artifact criteria. With fat-saturation images alone, the characterization sensitivity for teratomas and cystic hemorrhagic masses increased to 92% and 100%, respectively. Fat-saturation MR imaging was statistically superior to standard T1- and T2-weighted imaging in characterizing teratomas.
Adnexal Diseases↗
MR imaging of traumatic posterior urethral injury.
To assess the role of magnetic resonance (MR) imaging in defining the surgical approach and in predicting permanent erectile dysfunction in patients with traumatic posterior urethral injury, 27 patients underwent MR imaging before open urethral reconstruction. MR findings were correlated with surgical findings, surgical approach, and sexual potency at 12-month follow-up. MR imaging correctly revealed the length of the urethral injury (allowing for 0.5-cm discrepancy) in 23 of 27 (85%) patients and displacement of the prostatic apex in 19 of 21 (90%) patients. MR findings prompted a change in the clinically planned surgical approach from perineal to combined perineal and transpubic in seven (26%) cases. Significant variables affecting permanent impotence were avulsion of the corpus cavernosum, (P < .001), separation of the corporeal body (P < .05), and superior and/or lateral prostatic displacement (P < .05). When MR imaging findings of both cavernous avulsion and superior and/or lateral prostatic displacement were present, the probability of permanent impotence was 95%. In the absence of these findings, the probability of normal potency was 83%. MR imaging can be performed to help select the most effective surgical approach and to assess permanent erectile dysfunction.
Adolescent↗
Irradiation of the cervix uteri: value of unenhanced and contrast-enhanced MR imaging.
PURPOSE: To analyze the value of magnetic resonance (MR) imaging after radiation therapy for cancer of the cervix. MATERIALS AND METHODS: Eighty-nine MR images were retrospectively studied in 69 patients aged 46.3 years +/- 11.5. MR findings of tumor recurrence and irradiation changes were correlated with time after radiation therapy; paracentral radiation dose (dose to point A); and in patients with pretreatment images, primary tumor size and stage. RESULTS: Overall accuracy of MR in diagnosis of tumor recurrence was 78% (positive predictive value, 65%; negative predictive value, 97%). In MR examinations less than 6 months after the beginning of radiation therapy, accuracy (69%) and specificity (46%) were significantly lower than in examinations more than 6 months later (88%, P = .0032; 81%, P = .0166, respectively). Comparison of pre- and posttreatment MR findings and knowledge of stage or initial tumor size did not affect MR results. CONCLUSION: Overall, diagnosis was best with unenhanced T2-weighted images, but in patients with adnexal or pelvic sidewall recurrence and in patients with treatment complications (eg, fistula formation), contrast enhancement did help.
Adenocarcinoma↗
The role of MR imaging in determining surgical eligibility for pelvic exenteration.
OBJECTIVE: The purpose of this study was to evaluate the role of MR imaging in the preoperative assessment of candidates for pelvic exenteration. Specifically, we sought to determine if MR imaging was reliable in selecting patients with pelvic cancer for surgical exenteration. MATERIALS AND METHODS: MR images of the pelvis were retrospectively evaluated in 23 patients with proved pelvic cancer. These images were analyzed for (1) presence and location of the primary or recurrent tumor; (2) tumor extension to the bladder, rectum, or pelvic sidewall; and (3) presence and location of lymphadenopathy. On the basis of the MR findings, we determined suitability for pelvic exenteration by using generally accepted contraindications to surgery (involvement of the pelvic sidewall muscles or metastatic lymphadenopathy). In addition, tumor involvement of the bladder or rectum was evaluated to help determine the type of exenteration indicated. Surgical and/or histologic confirmation was available in all 23 cases. RESULTS: The accuracy of MR imaging in selecting patients was 83% (19 of 23), with a positive predictive value of 56% and a negative predictive value of 100%. In evaluating tumor involvement of the pelvic sidewall and lymph nodes, the negative predictive values were 100% and 95%, respectively. Tumor extension into the pelvic sidewall was overestimated in four patients, in three of whom it was not possible to distinguish radiation changes from tumor on MR images. For assessing extension of these pelvic tumors into the bladder and rectum, MR imaging had an accuracy of 81% and 85%, respectively. CONCLUSION: MR imaging may provide an accurate means of selecting patients considered for pelvic exenteration. MR accurately determined which patients should undergo the surgery, by demonstrating absence of sidewall abnormalities or adenopathy. Radiation changes could not be reliably distinguished from tumor involvement in those patients with sidewall abnormalities, however, especially in the first 6 to 12 months after treatment.
Adult↗
Diagnosis of urethral diverticula in women: value of MR imaging.
OBJECTIVE: The purpose of this study was to determine the role of MR imaging in the diagnosis of urethral diverticula in women. SUBJECTS AND METHODS: In 20 patients (mean age, 47 years), MR imaging was performed (1.5-T); unenhanced T1-weighted and T2-weighted images and contrast-enhanced T1-weighted images were obtained. MR imaging findings were compared with findings on urethrograms (including voiding cystourethrograms or double balloon catheter studies) in 16 patients, urethroscopic findings in 18, and surgical findings in 13. MR images were assessed for the presence, size, number, and location (anterior or posterior to the urethral lumen and relationship to the neck of the bladder) of diverticula, visualization of ostia, and presence of any concomitant complications. Sixteen of 20 patients had urethral diverticula: uncomplicated (simple) urethral diverticula in 13 patients; a diverticulum with a stone in one; a diverticulum with chronic granulation in one; and a diverticulum with adenocarcinoma in one. In the remaining four patients, the diagnoses included Gartner's duct cyst (one) and paraurethral cyst (one); urethras were deemed to be normal in two. RESULTS: In 13 patients who had surgery, MR images correctly showed the presence or absence of diverticula, whereas urethrography was correct in nine (69%) and urethroscopy in 10 (77%). Compared with surgical findings (20 diverticula in 12 patients), MR images depicted 14 (70%) of 20 diverticula and urethrography and urethroscopy each depicted 11 (55%) of 20. The ostium of the diverticulum could not be identified on MR images. The use of MR contrast material did not contribute to lesion detection, but the enhanced images were superior to unenhanced images in showing granulation tissue and carcinoma, although they did not help in their differentiation. CONCLUSION: MR imaging is accurate for showing urethral diverticula, but owing to its high cost, it should be considered only when urethroscopic or urethrographic findings are equivocal or when patients are unable to undergo these procedures and clinical findings strongly suggest a urethral diverticulum.
Adult↗
Female pelvis: overcoming hurdles to cancer staging.
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Contrast Media↗
The ovary. Computed tomography and magnetic resonance imaging.
CT and MR imaging can both contribute valuable clinical information in women with benign and malignant ovarian masses; the superior soft tissue contrast and multiplanar capabilities provided by MR imaging make it a valuable tool to evaluate the normal ovary, polycystic ovaries, endometriosis, and disorders of sexual differentiation. CT is currently the recommended modality to stage ovarian carcinoma, and peritoneal implants as small as 5 mm can be visualized. With the addition of contrast-enhanced images to conventional MR sequences, however, improved visualization of intratumoral architecture has also allowed for accurate MR characterization of benign versus malignant ovarian masses. Fat saturation techniques used with conventional MR sequences can also be used for definitive characterization of benign fat-containing teratomas and differentiate these tumors from hemorrhagic ovarian cysts or endometriomas. Finally, the detailed visualization of the normal-sized ovary on MR images provided by both the body coil and the new phased-array coil allows detection of the normal ovaries, ovarian follicles, and ovarian cysts throughout the premenopausal and postmenopausal years. Findings of polycystic ovarian syndrome, which cannot be evaluated by CT, are characteristic on MR images. MR is unparalleled in the evaluation of disorders of sexual differentiation because MR images can depict ectopic and normally positioned gonads and provide multiplanar depiction of the other pelvic organs and perineum as well. CT and MR imaging can provide valuable and specific clinical information about the ovary and benign and malignant ovarian disease.
Dermoid Cyst↗