Yasushi Kaji

Prostate cancer detection with 3 T MRI: Comparison of diffusion‐weighted imaging and dynamic contrast‐enhanced MRI in combination with T2‐weighted imaging

To evaluate the diagnostic ability of diffusion‐weighted imaging (DWI) and dynamic contrast‐enhanced imaging (DCEI) in combination with T2‐weighted imaging (T2WI) for the detection of prostate cancer using 3 T magnetic resonance imaging (MRI) with a phased‐array body coil.

Accuracy of 18F-FDG PET/CT in Detecting Pelvic and Paraaortic Lymph Node Metastasis in Patients with Endometrial Cancer

OBJECTIVE The objective of our study was to evaluate the accuracy of integrated PET and CT (PET/CT) using (18)F-FDG in detecting pelvic and paraaortic lymph node metastasis in patients with endometrial cancer, using surgical and histopathologic findings as the reference standard. SUBJECTS AND METHODS Forty patients with clinical stages IA to IIIC underwent radical hysterectomy, including pelvic lymphadenectomy with or without paraaortic lymphadenectomy, after FDG PET/CT. Lymphadenectomy involved removing all visible lymph nodes in the surgical fields. PET/CT findings were interpreted by two experienced radiologists in consensus and compared with histopathologic results. The criterion for malignancy on PET/CT images was increased radiotracer uptake by a lymph node independent of node size. RESULTS In total, 62 pathologically positive nodes were found in 10 patients and 60 of 62 dissected metastatic nodes were identified on the CT component. The overall node-based sensitivity, specificity, and accuracy of PET/CT for detecting nodal metastases were 53.3% (32/60), 99.6% (1,419/1,424), and 97.8% (1,451/1,484), respectively. The sensitivity for detecting metastatic lesions 4 mm or less in diameter was 16.7% (4/24), that for lesions between 5 and 9 mm was 66.7% (14/21), and that for lesions 10 mm or larger was 93.3% (14/15). The overall patient-based sensitivity, specificity, and accuracy were 50% (5/10), 86.7% (26/30), and 77.5% (31/40), respectively. CONCLUSION Integrated FDG PET/CT is superior to conventional imaging techniques, but it is only moderately sensitive in predicting lymph node metastasis preoperatively in patients with endometrial cancer. Even PET/CT should not replace lymphadenectomy.

Diagnostic accuracy of integrated FDG-PET/contrast-enhanced CT in staging ovarian cancer: comparison with enhanced CT

PurposeThe purpose of the study is to evaluate the accuracy of integrated positron emission tomography and computed tomography (PET/CT) with 18F-fluorodeoxyglucose (FDG) with IV contrast for preoperative staging of ovarian cancer, in comparison with enhanced CT, using surgical and histopathological findings as the reference standard.Materials and methodsForty patients with ovarian cancer underwent FDG-PET/contrast-enhanced CT scans for staging before primary debulking surgery. PET/CT and the CT component separately, were interpreted by two experienced radiologists by consensus for each investigation. Status with regard to lesion inside and outside the pelvis was determined on the basis of histopathology. The significance of differences between the two imaging modalities was determined using the McNemar test.ResultsStaging revealed stage I in 18 patients (IA, n = 9; IB, n = 3; IC, n = 6), stage II in seven (IIA, n = 2; IIB, n = 3; IIC, n = 2), stage III in 14 (IIIA, n = 1; IIIB, n = 3; IIIC, n = 10), and stage IV in one. The results of CT and PET/CT were concordant with the final pathological staging in 22 out of 40 (55%) and 30 out of 40 (75%) cases, respectively. The overall lesion-based sensitivity improved from 37.6% (32 out of 85) to 69.4% (59 out of 85), specificity from 97.1% (578 out of 595) to 97.5% (580 out of 595), and accuracy from 89.7% (610 out of 680) to 94.0% (639 out of 680) between CT and PET/CT. There were significant differences in sensitivity and accuracy, with p values of 5.6 × 10−7 and 1.2 × 10−7, respectively.ConclusionIntegrated FDG-PET/contrast-enhanced CT is a more accurate imaging modality for staging ovarian cancer and useful for selecting appropriate treatment than enhanced CT.

Conventional MRI Capabilities in the Diagnosis of Prostate Cancer in the Transition Zone

OBJECTIVES Our objectives were to evaluate the diagnostic capabilities of conventional MRI for the accurate detection of prostate cancer within the transition zone and to compare the results with histopathologic examination results. MATERIALS AND METHODS One hundred sixteen prostate specimens with prostate cancer were consecutively obtained. Axial, sagittal, and coronal T2- and T1-weighted MR images with gadopentetate dimeglumine were independently reviewed by two radiologists. The diagnostic base criteria of the MR images were determined for detecting transition zone cancer as follows: lesions with A, uniform low intensity on T2-weighted images; B, homogeneous gadolinium enhancement; and C, irregular margins both on gadolinium-enhanced and T2-weighted images. Wilcoxons rank sum and chi-square tests and receiver operating characteristic curves were used. Differences of less than 0.05 were considered significant. RESULTS Eighty-six lesions in the transition zone were analyzed. Histopathologic analysis showed 53 cancers and 33 benign lesions. The diagnostic sensitivity, specificity, and accuracy for cancer were 50%, 51%, and 51%, respectively with criteria A; 68%, 75%, and 71% with criteria B; and 60%, 72%, and 65% with criteria C. When base criteria were combined into criteria A-B, A-C, and B-C and then further divided into three subgroups, accuracy was found to be highest when the lesion satisfied any two criteria from A, B, and C than those of base criteria, combination criteria, and the other two subgroups. CONCLUSION The addition of gadolinium-enhanced MRI to T2-weighted imaging provides better accuracy for detecting cancerous transition zone lesions than the use of T2-weighted imaging alone.

Comparison of Magnetic Resonance Imaging and Ultrasonography in the Prenatal Diagnosis of Congenital Thoracic Abnormalities

Objectives: To evaluate prenatal MRI in the diagnosis of fetal thoracic abnormalities and to determine whether MRI provides useful information in addition to that of ultrasonography (US). Methods: Ultrafast MR scanning was performed in 7 pregnant women in whom US was suspicious of fetal congenital anomalies of the thorax [3 cases of congenital diaphragmatic hernia (CDH), 3 cases of chylothorax and 1 case of congenital cystic adenomatoid malformation (CCAM) type III]. The presence, position, size and characteristics of the congenital lesions were determined and compared with postnatal diagnoses. Results: The MRI diagnoses were 3 cases of CDH, 2 of chylothorax and one each of esophageal atresia and CCAM type III. The results of MRI were in agreement with those of US in 6 cases and in disagreement in 1 case of esophageal atresia. Final diagnoses were confirmed at surgery or autopsy in all fetuses. Combined use of MR and US imaging enabled a correct diagnosis in 5 cases and led to an error in the diagnosis of 1 fetus with bronchial stenosis, which had been diagnosed as CCAM type III by US and MRI. MRI led to a correct diagnosis in 1 fetus with esophageal atresia, in whom US had been equivocal in the prenatal diagnosis. Conclusion: MRI helped further characterize the fetal thoracic lesions and confirmed or changed the prenatal diagnosis based on US. MRI seems to be powerful in the prenatal diagnosis of thoracic lesions that are atypical or complicated by multiple abnormalities.

Spectrum of FDG PET/CT findings of uterine tumors

OBJECTIVE The purpose of this article is to review FDG PET/CT and MRI findings in a variety of benign and malignant tumors of the uterus and to become familiar with the wide variety of FDG PET/CT findings of this entity. CONCLUSION Benign uterine tumors generally have mild FDG uptake, and leiomyoma rarely shows high uptake. Uterine malignant tumors generally have intense FDG uptake, whereas malignant uterine tumors that are small or that have low cellular density often show minimal uptake.

Early Results of Magnetic Resonance–guided Focused Ultrasound Surgery of Adenomyosis: Analysis of 20 Cases

STUDY OBJECTIVE To evaluate the thermal ablative effects of magnetic resonance-(MR) guided focused ultrasound surgery (MRgFUS) on adenomyosis and to assess improvement in clinical parameters. DESIGN Twenty patients with adenomyosis were treated with MRgFUS. Extensive adenomyosis (6 cases) was treated with 2 applications. Uterine volume was evaluated by MR imaging before and immediately after MRgFUS. Ablation of adenomyosis and the architecture of nonperfused areas were evaluated immediately after MRgFUS. Improvement in patient symptoms was assessed through the symptom severity score questionnaire (Canadian Task Force classification II-3). SETTING Department of gynecology at a Japanese general hospital. PATIENTS Premenopausal women at least 18 years of age with symptomatic adenomyosis. INTERVENTIONS Thermal ablation by MRgFUS. MEASUREMENTS AND MAIN RESULTS We classified the nonperfused lesions on contrast-enhanced MR images immediately after MRgFUS into 3 types: lesions with round margins (type R), serrated margins (type S), and honeycomb architecture (type H). Type R was the most common (16/20 patients). Most adenomyosis lesions could be sufficiently ablated close to the serosal surface or to the endometrium by MRgFUS. The mean uterine volume 6 months after therapy was decreased by 12.7%. Symptom severity score improved significantly during 6 months of follow-up. No serious complications were observed. CONCLUSION These early results indicate the safe and effective ablation of adenomyosis tissue by MRgFUS. The procedure also resulted in the improvement in clinical symptoms during the 6 months of follow-up.

Performance of FDG-PET/CT for diagnosis of recurrent uterine cervical cancer

The purpose is to evaluate the accuracy of integrated FDG-PET/CT, compared with PET alone, for diagnosis of suspected recurrence of uterine cervical cancer. Fifty-two women who had undergone treatment for histopathologically proven cervical cancer received PET/CT with suspected recurrence. PET-alone and integrated PET/CT images were evaluated by two different experienced radiologists by consensus for each investigation. A final diagnosis was confirmed by histopathology, radiological imaging, and clinical follow-up for over 1 year. Patient-based analysis showed that the sensitivity, specificity, and accuracy of PET/CT were 92.0% (23/25), 92.6% (25/27), and 92.3% (48/52), respectively, while for PET, the corresponding figures were 80.0% (20/25), 77.8% (21/27), and 78.8% (41/52), respectively. PET/CT resolved the false-positive PET results due to hypermetabolic activity of benign/inflammatory lesions and physiological variants, and was able to detect lung metastasis, local recurrence, peritoneal dissemination, para-aortic lymph node metastasis, and pelvic lymph node metastasis missed by PET alone. However, tiny local recurrence and lymph node metastasis could not be detected even by PET/CT. FDG-PET/CT is a useful complementary modality for providing good anatomic and functional localization of sites of recurrence during follow-up of patients with cervical cancer.

Performance of Integrated FDG-PET/Contrast-enhanced CT in the Diagnosis of Recurrent Pancreatic Cancer: Comparison with Integrated FDG-PET/Non-contrast-enhanced CT and Enhanced CT

PurposeThe purpose of this study is to evaluate the accuracy of 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET)/computed tomography (CT) with intravenous contrast for depiction of recurrent pancreatic cancer, compared with PET/non-enhanced CT and CT.ProcedureForty-five patients previously treated for pancreatic cancer underwent PET/CT for suspected recurrence. Lesion status was determined on the basis of histopathology and radiological imaging follow-up.ResultsPatient-based analysis showed that sensitivity, specificity, and accuracy of PET/contrast-enhanced CT were 91.7%, 95.2%, and 93.3%, respectively, whereas those of PET/non-enhanced CT were 83.3%, 90.5%, and 86.7%, respectively, and those of enhanced CT were 66.7%, 85.7%, and 75.6%, respectively. In 21 patients whom the final diagnosis was obtained from the histopathologic examination, those figures of PET/contrast-enhanced CT were 94.7%, 50.0%, and 90.4%, respectively. The sensitivity of PET/contrast-enhanced CT in detecting local recurrence, abdominal lymph node metastasis, and peritoneal dissemination were 83.3%, 87.5%, and 83.3%, respectively.ConclusionPET/contrast-enhanced CT is an accurate modality for assessing recurrence of pancreatic cancer.

Performance of FDG-PET/CT in the diagnosis of recurrent endometrial cancer

ObjectiveTo evaluate the accuracy of integrated positron emission tomography and computed tomography (PET/CT) using 18-F-fluorodeoxyglucose (FDG), compared with PET alone, in the diagnosis of suspected endometrial cancer recurrence.MethodsThirty women who had undergone primary surgery for histopathologically proven endometrial cancer with suspected recurrence because of clinical, cytological, biochemical, and/or radiological findings were enrolled in this study. PET and integrated PET/CT images were evaluated by two different experienced radiologists by consensus for each modality. A final diagnosis of recurrence was confirmed by histopathology, other imaging and clinical follow-up for longer than 1 year. The statistical significance of differences between PET and PET/CT was determined by the McNemar test.ResultsPatient-based analysis showed that the sensitivity, specificity, and accuracy of PET/CT were 93% (14/15), 93% (14/15), and 93% (28/30), respectively, whereas for PET, the corresponding data were 80% (12/15), 80% (12/15), and 80% (24/30), respectively (P = 0.479, 0.479, and 0.134, respectively). CT from PET/CT resolved the false-positive PET results because of hyper-metabolic activity of benign inflammatory lesions and physiological variants and moreover detected lung metastasis and para-aortic lymph node metastasis that PET missed. However, tiny para-aortic lymph node metastasis could not be detected even with PET/CT.ConclusionsIntegrated FDG-PET/CT is a useful complementary modality for providing good anatomic and functional localization of sites of recurrence during follow-up of patients with endometrial cancer.