Is there a need for contrast-enhanced T1-weighted MRI of the spine after inconspicuous short τ inversion recovery imaging?

To assess the use of contrast-enhanced T1-weighted images in comparison with short inversion recovery (STIR) images for the detection of vertebral bone marrow abnormalities. A total of 201 vertebral magnetic resonance (MR) examinations were included in a prospective trial. Examinations were performed on a 0.5-T MR scanner. The examination protocol included STIR, T2-weighted turbo spin-echo and T1-weighted spin-echo images before and after administration of gadopentetate dimeglumine. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of STIR images were calculated. In the case of abnormal STIR images the additional information from contrast-enhanced images was evaluated using Fishers exact test. The value of the combined evaluation of STIR and contrast-enhanced T1-weighted images was compared with that of the combined assessment of T2-weighted and contrast-enhanced T1-weighted images. The PPV and the NPV of STIR images for detection of vertebral bone marrow abnormalities were 99.3 and 95.9%. In the case of normal STIR images no relevant additional information was found with contrast-enhanced T1-weighted images, while in the case of abnormal STIR images significant supplementary information was obtained. There was no difference in the diagnostic value when comparing combined assessment of STIR and contrast-enhanced T1-weighted images with combined evaluation of T2-weighted and contrast-enhanced T1-weighted images. Normal STIR images allow contrast-enhanced T1-weighted images for detection of bone marrow abnormalities to be omitted, whereas further imaging is needed in case of abnormal STIR images.     

Local staging of prostate cancer: comparative accuracy of T2-weighted endorectal MR imaging and transrectal ultrasound

ObjectiveThe objective of this study was to compare the accuracy of T2-weighted magnetic resonance (MR) imaging and transrectal ultrasound (TRUS) for staging of prostate cancer.Material and methodsA total of 101 men with biopsy-proven prostate cancer undergoing both T2-weighted endorectal MR imaging and B-mode TRUS for local tumor staging prior to radical prostatectomy were retrospectively identified. Three MR readers rated the likelihood of locally advanced disease using a 5-point scale. An ultrasound reader performed the same rating. Staging accuracy was compared using receiver operating characteristic curves.ResultsStaging accuracy was not significantly different between MR imaging (A_z = 0.69–0.70) and TRUS (A_z = 0.81, P>.05).ConclusionsT2-weighted MR imaging demonstrates comparable accuracy to B-mode TRUS for depicting locally invasive prostate cancer.     

Localization of prostate cancer using 3T MRI: comparison of T2-weighted and dynamic contrast-enhanced imaging

OBJECTIVE: To compare dynamic contrast-enhanced imaging and T2-weighted imaging using a 3T MR unit for the localization of prostate cancer. METHODS: Twenty consecutive patients with biopsy-proven prostate cancer underwent both T2-weighted imaging and dynamic contrast-enhanced imaging. At T2-weighted imaging and dynamic contrast-enhanced imaging, the presence or absence of prostate cancer confined within the prostate without extracapsular or adjacent organ invasion was evaluated in the peripheral zones of base, mid-gland, and apex on each side. Final decisions on prostate cancer localization were made by consensus between two radiologists. Degrees of depiction of tumor borders were graded as poor, fair, or excellent. RESULTS: Prostate cancer was pathologically detected in 64 (53%) of 120 peripheral zone areas. The sensitivity, specificity, and accuracy for prostate cancer detection were 55%, 88% and 70% for T2-weighted imaging and 73%, 77%, and 75% for dynamic contrast-enhanced imaging, respectively. Three cancer areas were detected only by T2-weighted imaging, 15 only by dynamic contrast-enhanced imaging, and 34 by both T2-weighted imaging and dynamic contrast-enhanced imaging. A fair or excellent degree at depicting tumor border was achieved in 67% by T2-weighted imaging and in 90% by dynamic contrast-enhanced imaging (P<0.05). CONCLUSIONS: Dynamic contrast-enhanced imaging at 3T MRI is superior to T2-weighted imaging for the detection and depiction of prostate cancer and thus is likely to be more useful for preoperative staging.     

Ovarian lesions: detection and characterization with gadolinium-enhanced MR imaging at 1.5 T

Magnetic resonance (MR) imaging for detection and characterization of ovarian masses was assessed in 33 patients with a total of 60 lesions. Lesions were characterized prospectively as benign or malignant by using T2-weighted MR images and unenhanced and gadolinium-enhanced T1-weighted MR images. MR imaging findings were compared with results of surgical laparotomy performed for staging of lesions. When malignancy was suspected, staging with MR imaging was performed. MR imaging demonstrated 57 of 60 (95%) surgically proved ovarian masses (34 of 36 were benign, 23 of 24 were malignant). Five significant primary criteria and four ancillary criteria for malignancy were established. For all MR pulse sequences combined, characterization of either type of lesion was correct in 84% of cases (48 of 57) when the five primary criteria were used and 95% (54 of 57) were correct when the four ancillary criteria were added. With gadolinium-enhanced images, correct characterization of malignant lesions increased from 56% to 78% with use of the five primary criteria and from 83% to 100% with use of both sets of criteria. Malignancies were correctly staged with MR imaging in 12 of 16 patients. Staging accuracy was 63% with unenhanced images and 75% with the addition of enhanced images.     

Percutaneous tumor ablation: increased necrosis with combined radio-frequency ablation and intratumoral doxorubicin injection in a rat breast tumor model

PURPOSE: To investigate the predictive value of magnetic resonance (MR) imaging of abnormalities of the lumbar intervertebral disks, particularly with adjacent endplate changes, to predict symptomatic disk derangement, with discography as the standard. MATERIALS AND METHODS: Fifty patients aged 28-50 years with chronic low back pain and without radicular leg pain underwent prospective clinical examination and sagittal T1- and T2-weighted and transverse T2-weighted MR imaging. Subsequently, patients underwent lumbar discography with a pain provocation test (116 disks). MR images were evaluated for disk degeneration, a high-signal-intensity zone, and endplate abnormalities. Results of pain provocation at discography were rated independently of the image findings as concordant or as nonconcordant or painless. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the clinical relevance of MR abnormalities. RESULTS: Normal disks on MR images were generally not painful at provocative discography (NPV, 98%). Disk degeneration (sensitivity, 98%; specificity, 59%; PPV, 63%) and a high-signal-intensity zone (sensitivity, 27%; specificity, 85%; PPV, 56%) were not helpful in the identification of symptomatic disk derangement. When only moderate and severe type I and type II endplate abnormalities were considered abnormal, all injected disks caused concordant pain with provocation (sensitivity, 38%; specificity, 100%; PPV, 100%). CONCLUSION: Moderate and severe endplate abnormalities appear be useful in the prediction of painful disk derangement in patients with symptomatic low back pain.     

Hepatocellular carcinoma in the cirrhotic liver: gadolinium-enhanced 3D T1-weighted MR imaging as a stand-alone sequence for diagnosis

PURPOSE: To retrospectively assess the usefulness of contrast material-enhanced T1-weighted magnetic resonance (MR) imaging alone and with T2-weighted MR imaging in the diagnosis of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A waiver of informed consent and institutional review board approval for this retrospective study were granted. The study was HIPAA compliant. Twenty-eight men (mean age, 49 years; range, 23-70 years) and 10 women (mean age, 53 years; range, 42-72 years) with cirrhosis underwent T2-weighted and contrast-enhanced T1-weighted MR imaging at 1.5 T within 90 days of liver transplantation. Three readers reviewed the T1-weighted images alone and then the T2-weighted and T1-weighted images together. Lesion detection, characterization, and reader confidence levels were recorded. RESULTS: At liver explantation, 57 lesions were present in 18 patients: 19 HCCs, 33 dysplastic nodules, and five cysts. Contrast-enhanced T1-weighted imaging depicted 13 of 19 HCCs with an overall sensitivity of 68.4% (13 of 19) and specificity of 65.7% (23 of 35). The sensitivity and specificity for detection of dysplastic nodules (sensitivity, 9%; specificity, 68.4%) and HCCs (sensitivity, 68.4%; specificity, 65.7%) were nearly identical for T1-weighted images read alone or read with T2-weighted images. The only difference was the specificity for T1-weighted images read alone (65.7%) and read with T2-weighted images (62.9%). The addition of T2-weighted images altered the diagnosis in one of 90 (1.1%) cases and provided an increase in diagnostic confidence in four of 258 (1.6%) cases for independent readers and three of 90 (3.3%) cases at consensus reading. CONCLUSION: Contrast-enhanced T1-weighted imaging can be used as a stand-alone sequence for the diagnosis of HCC in patients with cirrhosis prior to liver transplantation.     

The role of multi-parametric MR imaging in the detection of early inflammatory sacroiliitis according to ASAS criteria

Purpose

To retrospectively evaluate the accuracy of multi-parametric magnetic resonance (MR) imaging including fat saturated (FS) T2-weighted, short-tau inversion recovery (STIR), diffusion-weighted (DW-MR), and dynamic-contrast-enhanced MR (DCE-MR) imaging techniques in the diagnosis of early inflammatory sacroiliitis and determine the additional value of DW-MR and DCE-MR images according to recently defined ‘Assessment in SpondyloArthritis international Society’ criteria.

Materials and methods

The study included 45 patients with back pain. Two radiologists estimated the likelihood of osteitis in 4 independent viewing sessions including FS T2-weighted, STIR, DW-MR and DCE-MR images. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic (ROC) curve (AUC) were calculated.

Results

Of the 45 patients, 31 had inflammatory back pain. Of 31, 28 (90.3%) patients had inflammatory sacroiliitis diagnosed by clinical and laboratory analysis. FS T2-weighted MR images had the highest sensitivity (42.8% for both radiologists) for detecting osteitis in patients with inflammaory sacroiliitis when compared to other imaging sequences. For specificity, PPV, NPV, accuracy, and AUC levels there were no statistically significant difference between image viewing settings. However, adding STIR, DW-MR and DCE-MR images to the FS T2-weighted MR images did not improve the above stated indices.

Conclusion

FS T2-weighted MR imaging had the highest sensitivity when compared to other imaging sequences. The addition of DW-MR and DCE-MR images did not significantly improve the diagnostic value of MR imaging in the diagnosis of osteitis for both experienced and less experienced radiologists.     

Prostatic carcinoma: staging by clinical assessment, CT, and MR imaging

The sensitivity, specificity, accuracy, and positive and negative predictive values of clinical assessment, computed tomography (CT), and magnetic resonance (MR) imaging were compared in the differentiation of stage B from stage C prostatic carcinoma. Forty-six patients who had undergone radical prostatectomy were included in the study. Surgical-pathologic staging was considered the "truth measure." Clinical staging had an accuracy of 61%, and CT, 65%. Accuracy for MR imaging depended on the instrument parameters and plane of section used. When only transverse T1-weighted images were analyzed, MR accuracy was 61%. However, when transverse T1- and T2-weighted images supplemented by additional T2-weighted coronal or sagittal images were studied, accuracy increased to 83%. At present, MR imaging is the most accurate diagnostic modality for the local staging of carcinoma of the prostate, but for optimal results, multiple sequences and two orthogonal planes of imaging are needed.     

MR imaging of leptomeningeal metastases: comparison of three sequences

BACKGROUND AND PURPOSE: Recent work has shown that fluid-attenuated inversion recovery (FLAIR) imaging with contrast enhancement is highly sensitive for detecting subarachnoid space disease. We hypothesized that contrast-enhanced FLAIR imaging has superior sensitivity to contrast-enhanced T1-weighted MR imaging in detecting leptomeningeal metastases. METHODS: Sixty-eight patients referred for suspected leptomeningeal metastases underwent 74 MR imaging studies. The patients had either temporally related cytologic proof of leptomeningeal metastases or negative results of clinical follow-up confirming absence of leptomeningeal metastases. The MR imaging examinations included unenhanced and contrast-enhanced FLAIR images and contrast-enhanced T1-weighted MR images that were independently reviewed by two neuroradiologists blinded to the results of cytology. Each of the three sequences was reviewed individually and separately and was assigned a score of positive or negative for leptomeningeal metastases. Discrepancies were settled by consensus. RESULTS: Of the 17 studies of patients with cytology-proven leptomeningeal metastases, two were positive based on unenhanced FLAIR images, seven were positive based on contrast-enhanced FLAIR images, and 10 were positive based on contrast-enhanced T1-weighted MR images. Of the 57 studies of patients without leptomeningeal metastases, 53 were negative based on unenhanced FLAIR images, 50 were negative based on contrast-enhanced FLAIR images, and 53 were negative based on contrast-enhanced T1-weighted MR images. The sensitivity and specificity of unenhanced FLAIR images for detecting leptomeningeal metastases were 12% (two of 17) and 93% (53 of 57), respectively. The sensitivity and specificity for contrast-enhanced FLAIR images for detecting leptomeningeal metastases were 41% (seven of 17) and 88% (50 of 57), respectively. The sensitivity and specificity of contrast-enhanced T1-weighted MR images for detecting leptomeningeal metastases were 59% (10 of 17) and 93% (53 of 57), respectively. CONCLUSION: Contrast-enhanced fast FLAIR sequences are less sensitive than standard contrast-enhanced T1-weighted MR sequences in detecting intracranial neoplastic leptomeningeal disease.     

Prostate cancer localization with dynamic contrast-enhanced MR imaging and proton MR spectroscopic imaging

PURPOSE: To prospectively determine the accuracies of T2-weighted magnetic resonance (MR) imaging, dynamic contrast material-enhanced MR imaging, and quantitative three-dimensional (3D) proton MR spectroscopic imaging of the entire prostate for prostate cancer localization, with whole-mount histopathologic section findings as the reference standard. MATERIALS AND METHODS: This study was approved by the institutional review board, and informed consent was obtained from all patients. Thirty-four consecutive men with a mean age of 60 years and a mean prostate-specific antigen level of 8 ng/mL were examined. The median biopsy Gleason score was 6. T2-weighted MR imaging, dynamic contrast-enhanced MR imaging, and 3D MR spectroscopic imaging were performed, and on the basis of the image data, two readers with different levels of experience recorded the location of the suspicious peripheral zone and central gland tumor nodules on each of 14 standardized regions of interest (ROIs) in the prostate. The degree of diagnostic confidence for each ROI was recorded on a five-point scale. Localization accuracy and ROI-based receiver operating characteristic (ROC) curves were calculated. RESULTS: For both readers, areas under the ROC curve for T2-weighted MR, dynamic contrast-enhanced MR, and 3D MR spectroscopic imaging were 0.68, 0.91, and 0.80, respectively. Reader accuracy in tumor localization with dynamic contrast-enhanced imaging was significantly better than that with quantitative spectroscopic imaging (P < .01). Reader accuracy in tumor localization with both dynamic contrast-enhanced imaging and spectroscopic imaging was significantly better than that with T2-weighted imaging (P < .01). CONCLUSION: Compared with use of T2-weighted MR imaging, use of dynamic contrast-enhanced MR imaging and 3D MR spectroscopic imaging facilitated significantly improved accuracy in prostate cancer localization.     

Diagnostic radiology of the pelvis. Prostate cancer, bladder cancer, and incontinence

Prostate cancer, bladder cancer, and pelvic floor weakness are among the most common diseases of the pelvis. Cardinal symptoms include painless macrohematuria in bladder cancer and urinary and fecal incontinence in pelvic floor weakness. Suspicion of prostate cancer currently is most frequently raised when the serum concentration of prostate-specific antigen is pathologically elevated. Besides extensive clinical and invasive diagnosis, clinical imaging is frequently applied for the localization, locoregional staging, and diagnosis of recurrence of prostate cancer and invasive bladder cancer, and in clinically difficult cases of cystocele, enterocele, rectocele, descensus or prolapse of vagina, uterus, and rectum, and rectal intussusception. Magnetic resonance imaging with T2-weighted TSE or FSE images in several planes combined with either axial, T1-weighted images and MR spectroscopy for the prostate, dynamic contrast-enhanced T1-weighted images for the urinary bladder, or dynamic T2-weighted functional images for pelvic floor incontinence are particularly well suited as clinical imaging methods.     

比较3.0T MRI平扫及增强扫描对宫颈癌分期的价值

目的：通过与手术病理分期对比,比较MRI平扫及增强扫描在宫颈癌分期中的价值。方法：搜集75例经手术病理证实的宫颈癌患者,由2位工作经验丰富的放射科医师共同对其MRI平扫及增强图像进行评价,包括肿瘤位置、大小、边界清晰度、信号特征、对周围组织的侵犯情况,并分别根据MRI平扫及增强表现对所有患者进行分期,以手术病理分期为金标准,比较两种分期方法对宫颈癌总体分期准确性,各期别分期准确性差异。结果：MRI增强扫描显示肿瘤边界明显较MRI平扫清晰（P〈0．001）;MRI增强及平扫对宫颈癌总体分期准确度分别为85．3％、77．3％,在对宫颈癌Ia、Ⅱa、Ⅱb各期别分期评判中,MRI增强准确度分别为89．3％、85．3％、96．0％,MRI平扫准确度分别为84．0％、77．3％、93．3％,统计学分析表明MRI平扫及增强扫描在宫颈癌总体分期及Ig、Ⅱa、Ⅱb各期别分期准确性差异均无统计学意义（P均〉0．05）。结论：在宫颈癌分期方面,MRI增强准确性优于MRI平扫,但两者差异无统计学意义。     

MR imaging of pelvic masses in women: contrast-enhanced vs unenhanced images.

OBJECTIVE. We compared the value of contrast-enhanced MR images with that of T2-weighted MR images in the diagnosis and staging of pelvic masses in women. MATERIALS AND METHODS. The findings on preoperative MR studies of 97 patients with a total of 124 surgically proved lesions were retrospectively analyzed. Unenhanced T1- and T2-weighted spin-echo images were compared with contrast-enhanced T1-weighted images. The final diagnosis included benign (36 patients), borderline (six patients), and malignant (15 patients) ovarian masses, fallopian tube masses (15 patients), endometrial tumors (seven patients), cervical carcinomas (32 patients), subserous leiomyomas (11 patients), and two masses of extragenital origin. RESULTS. In the depiction of pelvic lesions, the sensitivity of contrast-enhanced MR imaging (96%) was equal to that of unenhanced T2-weighted imaging (97%). Contrast-enhanced images were useful in the definition of intratumoral architecture and tumor borders of 72 adnexal masses, resulting in better determination of malignancy (accuracy, 95%) than on T2-weighted images (85%). Size of viable tumor, differentiation of tumor from retained fluid, and depth of myometrial invasion of six endometrial carcinomas were most reliably shown on contrast-enhanced images. In the evaluation of cervical carcinoma, overall staging accuracy of contrast-enhanced imaging (80%) was slightly inferior to that of T2-weighted imaging (83%). However, contrast-enhanced images improved assessment of parametrial and organ invasion in seven cases in which findings on T2-weighted MR images were equivocal. Administration of contrast material was not helpful in the evaluation of subserous leiomyomas or masses of extragenital origin. CONCLUSIONS. The findings suggest that when results of unenhanced T1- and T2-weighted MR imaging of pelvic masses are equivocal, contrast-enhanced MR images should be used as supportive and complementary pulse sequences to (1) improve definition of intratumoral architecture and prediction of malignancy in adnexal tumors, (2) stage endometrial carcinoma, and (3) determine tumor extension in cervical carcinoma.     

Radiologische Beckendiagnostik

Prostate cancer, bladder cancer, and pelvic floor weakness are among the most common diseases of the pelvis. Cardinal symptoms include painless macrohematuria in bladder cancer and urinary and fecal incontinence in pelvic floor weakness. Suspicion of prostate cancer currently is most frequently raised when the serum concentration of prostate-specific antigen is pathologically elevated. Besides extensive clinical and invasive diagnosis, clinical imaging is frequently applied for the localization, locoregional staging, and diagnosis of recurrence of prostate cancer and invasive bladder cancer, and in clinically difficult cases of cystocele, enterocele, rectocele, descensus or prolapse of vagina, uterus, and rectum, and rectal intussusception. Magnetic resonance imaging with T2-weighted TSE or FSE images in several planes combined with either axial, T1-weighted images and MR spectroscopy for the prostate, dynamic contrast-enhanced T1-weighted images for the urinary bladder, or dynamic T2-weighted functional images for pelvic floor incontinence are particularly well suited as clinical imaging methods.     

Glioma grading: sensitivity, specificity, and predictive values of perfusion MR imaging and proton MR spectroscopic imaging compared with conventional MR imaging

BACKGROUND AND PURPOSE: Sensitivity, positive predictive value (PPV), and negative predictive value (NPV) of conventional MR imaging in predicting glioma grade are not high. Relative cerebral blood volume (rCBV) measurements derived from perfusion MR imaging and metabolite ratios from proton MR spectroscopy are useful in predicting glioma grade. We evaluated the sensitivity, specificity, PPV, and NPV of perfusion MR imaging and MR spectroscopy compared with conventional MR imaging in grading primary gliomas. METHODS: One hundred sixty patients with a primary cerebral glioma underwent conventional MR imaging, dynamic contrast-enhanced T2*-weighted perfusion MR imaging, and proton MR spectroscopy. Gliomas were graded as low or high based on conventional MR imaging findings. The rCBV measurements were obtained from regions of maximum perfusion. Metabolite ratios (choline [Cho]/creatine [Cr], Cho/N-acetylaspartate [NAA], and NAA/Cr) were measured at a TE of 144 ms. Tumor grade determined with the three methods was then compared with that from histopathologic grading. Logistic regression and receiver operating characteristic analyses were performed to determine optimum thresholds for tumor grading. Sensitivity, specificity, PPV, and NPV for identifying high-grade gliomas were also calculated. RESULTS: Sensitivity, specificity, PPV, and NPV for determining a high-grade glioma with conventional MR imaging were 72.5%, 65.0%, 86.1%, and 44.1%, respectively. Statistical analysis demonstrated a threshold value of 1.75 for rCBV to provide sensitivity, specificity, PPV, and NPV of 95.0%, 57.5%, 87.0%, and 79.3%, respectively. Threshold values of 1.08 and 1.56 for Cho/Cr and 0.75 and 1.60 for Cho/NAA provided the minimum C2 and C1 errors, respectively, for determining a high-grade glioma. The combination of rCBV, Cho/Cr, and Cho/NAA resulted in sensitivity, specificity, PPV, and NPV of 93.3%, 60.0%, 87.5%, and 75.0%, respectively. Significant differences were noted in the rCBV and Cho/Cr, Cho/NAA, and NAA/Cr ratios between low- and high-grade gliomas (P <.0001,.0121,.001, and.0038, respectively). CONCLUSION: The rCBV measurements and metabolite ratios both individually and in combination can increase the sensitivity and PPV when compared with conventional MR imaging alone in determining glioma grade. The rCBV measurements had the most superior diagnostic performance (either with or without metabolite ratios) in predicting glioma grade. Threshold values can be used in a clinical setting to evaluate tumors preoperatively for histologic grade and provide a means for guiding treatment and predicting postoperative patient outcome.     

Periampullary tumors: high-spatial-resolution MR imaging and histopathologic findings in ampullary region specimens

PURPOSE: To prospectively determine the magnetic resonance (MR) signal intensity characteristics of structures of the ampullary region and to assess the potential use of MR imaging in evaluation of the extent of periampullary tumors in resected specimens. MATERIALS AND METHODS: Twenty-five specimens from the ampullary region obtained in four autopsy cases without periampullary tumors and in 21 patients with periampullary tumors were examined with a 1.5-T MR system and a circular surface coil with 5-inch (12.7-cm) diameter. High-spatial-resolution MR images were obtained with field of view of 100 x 100 mm, matrix of 256 x 256 or 512 x 256, and section thickness of 2 mm. MR imaging findings were compared with histopathologic findings. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of high-spatial-resolution MR imaging for assessment of tumor invasion into surrounding tissues were evaluated by two radiologists. RESULTS: T1- and T2-weighted MR images clearly depicted normal structures in the ampullary region that included Oddi muscle, duodenal wall, common bile duct, and pancreas; these findings corresponded well with histologic findings. In 20 (95%) of 21 tumors, high-spatial-resolution MR imaging depicted location and extension of periampullary tumors precisely. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of high-spatial-resolution MR imaging for assessment of tumor invasion into surrounding tissue were 88%, 100%, 96%, 100%, and 94%, respectively. CONCLUSION: In this study, MR imaging correctly depicted location, extension, and origin of tumor. High-spatial-resolution MR imaging has potential for presurgical staging of tumors in this region.     

Brachytherapy for prostate cancer: endorectal MR imaging of local treatment-related changes

PURPOSE: To determine the local treatment-related endorectal magnetic resonance (MR) imaging findings after brachytherapy for prostate cancer. MATERIALS AND METHODS: Endorectal MR imaging was performed in 35 consecutive patients at a mean interval of 12 months (range, 1-31 months) after brachytherapy for prostate cancer. Transverse T1-weighted and high-spatial-resolution transverse and coronal T2-weighted images were acquired. Two readers reviewed MR image quality and findings, with discrepancies resolved by consensus. Posttreatment urinary symptoms in patients (n = 24) were documented by using chart review. RESULTS: All studies were of diagnostic quality. On T2-weighted images, prostatic findings consisted of diffuse low signal intensity (n = 35) and indistinct zonal anatomy (n = 34). Intra- and extraprostatic seed locations could be distinguished. The most common extraprostatic site of seed implantation was the neurovascular bundles (n = 35, bilateral in 32). The most common extraprostatic tissue finding was increased signal intensity on T2-weighted images in the levator ani muscle (n = 34) and the genitourinary diaphragm (n = 28). Postbrachytherapy urinary symptoms showed no demonstrable correlation with periurethral or genitourinary diaphragm seed implantation or with signal intensity change in the genitourinary diaphragm. CONCLUSION: Endorectal MR imaging can be used to evaluate seed distribution and to demonstrate treatment-related changes after brachytherapy for prostate cancer.     

Hepatic lesion detection and characterization: value of nonenhanced MR imaging, superparamagnetic iron oxide-enhanced MR imaging, and spiral CT-ROC analysis

PURPOSE: To determine the accuracy for detection and characterization of focal hepatic lesions of nonenhanced, superparamagnetic iron oxide (SPIO)-enhanced, or a combination of nonenhanced and SPIO-enhanced MR imaging and contrast-enhanced spiral computed tomography (CT). MATERIALS AND METHODS: Spiral CT and T2-weighted SPIO-enhanced (ferucarbotran-enhanced) MR imaging were performed in 35 patients within 2 weeks before surgery for malignant hepatic lesions. Only malignant lesions with histopathologic proof were considered. A total of 875 images with and 800 images without focal lesions were presented to five readers, who were asked to assess the presence and characterization of lesions by using a five-point confidence scale. Receiver operating characteristic analysis was performed. RESULTS: Nonenhanced and SPIO-enhanced images together and SPIO-enhanced images alone yielded the best performance for lesion detection. No differences were found among all imaging techniques with regard to lesion characterization (benign vs malignant). The combined approach resulted in larger area under the ROC curve (A(z) = 0.9062) and accuracy (85.3%) (P < 0.02), as compared with SPIO-enhanced MR imaging (A(z) = 0.8667; accuracy, 73.1%). CONCLUSION: SPIO-enhanced T2-weighted MR imaging was more accurate than nonenhanced T1-weighted and T2-weighted MR imaging and contrast-enhanced spiral CT for the detection of focal hepatic lesions. The combined analysis of nonenhanced and SPIO-enhanced images was more accurate in the characterization of focal hepatic lesions than was review of SPIO-enhanced images alone.     

Breast imaging. Preoperative breast cancer staging: comparison of USPIO-enhanced MR imaging and 18F-fluorodeoxyglucose (FDC) positron emission tomography (PET) imaging for axillary lymph node staging—initial findings

Magnetic resonance (MR) imaging after ultra-small super paramagnetic iron oxide (USPIO) injection and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for preoperative axillary lymph node staging in patients with breast cancer were evaluated using histopathologic findings as the reference standard. USPIO-enhanced MR and FDG-PET were performed in ten patients with breast cancer who were scheduled for surgery and axillary node resection. T2-weighted fast spin echo, T1-weighted three-dimensional (3D) gradient echo, T2*-weighted gradient echo and gadolinium-enhanced T1-weighted 3D gradient echo with spectral fat saturation were evaluated. MR imaging before USPIO infusion was not performed. The results were correlated with FDG-PET (acquired with dedicated PET camera, visual analysis) and histological findings. The histopathologic axillary staging was negative for nodal malignancy in five patients and positive in the remaining five patients. There was one false positive finding for USPIO-enhanced MR and one false negative finding for FDG-PET. A sensitivity (true positive rate) of 100%, specificity (true negative rate) of 80%, positive predictive value of 80%, and negative predictive value of 100% were achieved for USPIO-enhanced MR and of 80%, 100%, 100%, 80% for FDG-PET, respectively. The most useful sequences in the detection of invaded lymph nodes were in the decreasing order: gadolinium-enhanced T1-weighted 3D gradient echo with fat saturation, T2*-weighted 2D gradient echo, T1-weighted 3D gradient echo and T2-weighted 2D spin echo. In our study, USPIO-enhanced T1 gradient echo after gadolinium injection and fat saturation emerged as a very useful sequence in the staging of lymph nodes. The combination of USPIO-enhanced MR and FDG-PET achieved 100% sensitivity, specificity, PPV and NPV. If these results are confirmed, the combination of USPIO MR with FDG-PET has the potential to identify the patient candidates for axillary dissection versus sentinel node lymphadenectomy.