[18F]Fluorodeoxyglucose uptake by positron emission tomography predicts outcomes for oropharyngeal and hypopharyngeal cancer treated with definitive radiotherapy.

This study evaluated the prognostic significance of the maximum standardized uptake value of the primary site (pSUVmax) in 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans of patients with oropharyngeal or hypopharyngeal cancer who were treated using definitive radiotherapy. The study included 86 patients who were primarily treated with radiotherapy for oropharyngeal or hypopharyngeal cancer. Sixty-nine patients underwent concurrent chemotherapy. The associations between pre-treatment pSUVmax and treatment outcomes were evaluated. The most appropriate pSUVmax cut-off value for predicting disease-free survival (DFS) and local control (LC) was selected using receiver operating characteristic (ROC) curves. The median follow-up time for surviving patients was 60 months, while the median survival time in the entire patient cohort was 55 months. A pSUVmax cut-off value of 9.0 showed the best discriminative performance. Five-year OS and DFS rates were 65.9% and 60.0%, respectively. In univariate analyses, pSUVmax (p = 0.009), T-stage (p = 0.001), N-stage (p = 0.039), and clinical stage (p = 0.017) were identified as significant prognostic predictors for DFS. The multivariate analysis did not identify any statistically significant factors, but the association between pSUVmax and DFS was borderline significant (p = 0.055). Interestingly, pSUVmax was predictive of local controllability in T1-T2 disease (p = 0.024), but there was no significant association for T3-T4 disease (p = 0.735). In this study, pSUVmax was predictive of DFS and LC in patients with oropharyngeal or hypopharyngeal cancer that was treated with definitive radiotherapy. pSUVmax was strongly associated with LC in T1-T2 disease.

Evaluation of interobserver variability and diagnostic performance of developed MRI-based radiological scoring system for invasive placenta previa.

PURPOSE: To evaluate the interobserver variability and diagnostic performance of a developed magnetic resonance imaging (MRI)-based scoring system for invasive placenta previa. MATERIALS AND METHODS: Prenatal MR images of 70 women were retrospectively evaluated, 18 of whom were diagnosed with invasive placenta. The six MR features (dark band on T2 -weighted images, intraplacental abnormal vascularity, placental bulge, heterogeneous placenta, myometrial thinning, and placental protrusion sign) were scored on 5-point Likert scale separately, and the cumulative radiological score (CRS) was defined as the sum of each score. Two more experienced radiologists (readers A and B) and two less experienced residents (readers C and D) calculated the CRS. Interobserver variability was assessed by measuring the intraclass correlation coefficient. Diagnostic performance was evaluated by means of receiver operating characteristic (ROC) analysis. RESULTS: Interobserver variability for CRS was excellent for the more experienced radiologists (0.85), and good for all readers (0.72) and the less experienced residents (0.66). The area under the ROC curve (Az) and accuracy (Acc) for CRS were significantly higher or equivalent to those of other MR features for all readers (Az and Acc for reader A; CRS, 0.92, 91.4%; intraplacental T2 dark band, 0.83, P = 0.009, 81.4%, P = 0.03; intraplacental abnormal vascularity, 0.9, P = 0.3, 90.0%, P = 1.00; placental bulge, 0.81, P = 0.0008, 80.0%, P = 0.02; heterogeneous placenta, 0.85, P = 0.11, 74.3%, P = 0.002; myometrial thinning, 0.84, P = 0.06, 60.0%, P < 0.0001; placental protrusion sign, 0.81, P = 0.01, 81.4%, P = 0.26). CONCLUSION: This developed MRI-based scoring system demonstrated excellent or good interobserver variability, and good diagnostic performance for invasive placenta previa. J. Magn. Reson. Imaging 2016;44:573-583.

FDG-PET/contrast-enhanced CT as a post-treatment tool in head and neck squamous cell carcinoma: comparison with FDG-PET/non-contrast-enhanced CT and contrast-enhanced CT.

OBJECTIVE: To evaluate the accuracy of PET/CT using (18)F-fluorodeoxyglucose (FDG) with IV contrast for suspected recurrent head and neck squamous cell carcinoma (HNSCC). METHODS: One hundred and seventy patients previously treated for HNSCC underwent PET/CT, consisting of non-contrast-enhanced and contrast-enhanced CT, to investigate suspected recurrence. Diagnostic performance of PET/contrast-enhanced CT (PET/ceCT), PET/non-contrast-enhanced CT (PET/ncCT) and contrast-enhanced CT (ceCT) for local or regional recurrence, distant metastasis, overall recurrence and second primary cancer was evaluated. The reference standard included histopathology, treatment change and imaging follow-up. RESULTS: The patient-based areas under the receiver operating characteristic curves (AUC) for ceCT, PET/ncCT and PET/ceCT were 0.82, 0.96 and 0.98 for local recurrence, 0.73, 0.86 and 0.86 for regional recurrence, 0.86, 0.91 and 0.92 for distant metastasis, 0.72, 0.86 and 0.87 for overall recurrence, and 0.86, 0.89 and 0.91 for a second primary cancer. Both PET/ceCT and PET/ncCT statistically showed larger AUC than ceCT for recurrence, and the difference between PET/ceCT and PET/ncCT for local recurrence reached a significant level (p = 0.039). The accuracy of PET/ceCT for diagnosing overall recurrence was high, irrespective of the time interval after the last treatment (83.3-94.1 %). CONCLUSION: FDG-PET/CT was a more accurate HNSCC restaging tool than ceCT. The added value of ceCT at FDG-PET/CT is minimal. KEY POINTS: • FDG-PET/CT is a more accurate post-treatment surveillance tool than ceCT for HNSCC. • FDG-PET/ceCT was useful, irrespective of the time interval after the last treatment. • FDG-PET/ceCT showed high negative predictive value and limited positive predictive value. • The added value of ceCT at FDG-PET/CT is minimal and likely not clinically relevant.

Preoperative risk stratification using metabolic parameters of (18)F-FDG PET/CT in patients with endometrial cancer.

PURPOSE: To evaluate the usefulness of metabolic parameters obtained by (18)F-FDG PET/CT for preoperative stratification of high-risk and low-risk endometrial carcinomas. METHODS: Preoperative (18)F-FDG PET/CT was performed in 56 women with endometrial cancer. Maximum standardized uptake values (SUVmax), metabolic tumour volume (MTV) and total lesion glycolysis (TLG) of primary tumours were compared with clinicopathological features of surgical specimens. Diagnostic performance in terms of differentiation of low-risk disease (endometrioid histology, histological grade 1 or 2, invasion of less than half of the myometrium, and FIGO stage I) from high-risk disease was assessed. RESULTS: MTV and TLG were significantly higher in patients with higher histological grade (p = 0.0026 and p = 0.034), larger tumour size (p = 0.002 and p = 0.0017), lymphovascular space involvement (LVSI; p = 0.012 and p = 0.0051), myometrial invasion (p = 0.027 and p = 0.031), cervical stromal invasion (p = 0.023 and p = 0.014), ovarian metastasis (p = 0.00022 and p = 0.00034), lymph node metastasis (p < 0.0001 and p < 0.0001), and higher FIGO stage (p = 0.0011 and p = 0.00048). SUVmax was significantly higher in patients with larger tumour size (p = 0.0025), LVSI (p = 0.00023) and myometrial invasion (p < 0.0001). The areas under the ROC curves (AUCs) for distinguishing high-risk from low-risk carcinoma were 0.625, 0.829 and 0.797 for SUVmax, MTV and TLG, respectively. AUCs for both MTV and TLG were significantly larger than that for SUVmax (p = 0.0049 and p = 0.021). The optimal TLG cut-off value of 70.2, determined by ROC analysis, was found to have 72.0% sensitivity and 74.2% specificity for risk stratification. CONCLUSION: MTV and TLG of primary endometrial cancer show better correlations with clinicopathological features and are more useful for differentiating high-risk from low-risk carcinoma than SUVmax.

Novel MRI finding for diagnosis of invasive placenta praevia: evaluation of findings for 65 patients using clinical and histopathological correlations.

OBJECTIVE: To review established magnetic resonance (MR) criteria and describe a new MR finding for the diagnosis of invasive placenta praevia. METHODS: A retrospective review of prenatal MRI examinations of 65 patients (median age: 35 years) who underwent MR for the screening of invasive placenta praevia. All MRIs were performed on a 1.5-T unit, including axial, coronal and sagittal T2-weighted half-Fourier single-shot turbo spin echo imaging. Fifteen patients were diagnosed with invasive placenta praevia. Two experienced radiologists reviewed the MR images and evaluated a total of six MRI features of the placenta, including our novel finding of the placental protrusion into the internal os (placental protrusion sign). Inter-rater reliability was assessed by using kappa statistics. Features with a kappa statistic >0.40 were evaluated using Fisher's two-sided exact test for comparison of their capabilities for placental invasion assessment. RESULTS: Interobserver reliability was moderate or better for the intraplacental T2 dark band, intraplacental abnormal vascularity, uterine bulging, heterogeneous placenta and placental protrusion sign. Fisher's two-sided exact test results showed all these features were significantly associated with invasive placenta praevia. CONCLUSION: The novel MRI finding of a placental protrusion sign is a useful addition to the established MRI findings for the diagnosis of invasive placenta praevia. KEY POINTS: • Prenatal diagnosis for an invasive placenta is essential for perinatal planning. • Magnetic resonance imaging provides useful information for the diagnosis of invasive placenta. • The placental protrusion sign is a useful novel MRI finding for predicting invasive placenta.

Two cases of idiopathic multicentric Castleman disease with nephrotic syndrome treated with tocilizumab.

We report two cases of idiopathic multicentric Castleman disease (iMCD) with nephrotic syndrome (NS) treated with tocilizumab. Case 1 was a 58-year-old man diagnosed with iMCD prior to the onset of NS. Renal biopsy revealed membranous nephropathy, which was considered to be secondary membranous nephropathy associated with iMCD. Case 2 was a 49-year-old woman diagnosed with iMCD prior to NS. Renal biopsy revealed renal amyloidosis positive for Congo red staining and amyloid A protein immunostaining. In both the cases, the proteinuria improved after the initiation of glucocorticoid and tocilizumab therapy. Tocilizumab may be a good therapeutic choice for iMCD with NS.

Value of three-dimensional T2-weighted turbo spin-echo imaging with tissue-specific variable refocusing flip angle for 3-T magnetic resonance imaging of prostate cancer: comparison with conventional two- and three-dimensional T2-weighted turbo spin-echo imaging.

PURPOSE: To investigate the impact of three-dimensional (3D) T2-weighted turbo spin-echo imaging (TSE-T2WI) with tissue-specific variable refocusing flip angle (TS-VRFA) on image quality and prostate cancer (PCa) detection and extraprostatic extension (EPE) evaluation compared to 2D TSE-T2WI and conventional 3D TSE-T2WI with volume isotropic TSE acquisition (VISTA). MATERIALS AND METHODS: Image data sets of 40 patients who underwent 3-T MRI before prostatectomy, including multiplane 2D T2WI, 3D T2WI with TS-VRFA and VISTA, and diffusion-weighted images were independently evaluated by two radiologists. The detectability of PCa and EPE of each sequence was assessed using areas by the receiver operating characteristic curve (AUC) analysis. Image quality measures and contrast ratios (CR) between cancerous lesions and non-cancerous regions for each T2WI were also evaluated. RESULTS: Overall image quality of TS-VRFA was better than that of VISTA and equivalent to 2D. The highest CR was obtained with TS-VRFA (P < 0.05). For both readers, no significances were observed in detectability for PCa detection between three sequences (P > 0.05). For both readers, there were no significant differences in AUC for EPE evaluation between three sequences (P > 0.05). CONCLUSION: 3D T2 WI using TS-VRFA could potentially replace multiplane 2D T2 WI for prostate cancer diagnosis with better image quality than VISTA.

Length of the memory retention period depends on the extent of protein synthesis in the terrestrial slug Limax.

The terrestrial slug Limax can form an odor-aversion memory by the single simultaneous presentation of a food odor and an aversive stimulus. We have previously demonstrated that the long-term retention of this memory was impaired by a high-dose injection of a protein synthesis inhibitor 30min prior to the conditioning. However, the onset of amnesia was delayed if the dose of the inhibitor was reduced or a less potent protein synthesis inhibitor was used. We thus speculated that the persistence of memory depends on the amount of newly synthesized protein following learning. In the present study, we further elaborated on this idea by injecting a high dose of anisomycin at different timings before or after conditioning, and tested the memory retention at 1, 2, 3, 7, or 14days after the conditioning. We found that the injection of anisomycin 6h before, or 1h after the conditioning had no effect on memory retention for 7days, and an injection at 30min before and just following the conditioning impaired the memory retention at 3days. Interestingly, the injection at 3h before and 30min after the conditioning did not impair the retention at 3days but did impair retention at 7days. Taking into account the time course of protein synthesis inhibition in the brain, our results further support the idea that the memory retention period is dependent on the amount of protein synthesized following memory acquisition.

[(18)F]-FDG PET/CT imaging for detection of nodal metastases in patients with squamous cell carcinoma of the pharynx and larynx: comparison with CT.

PURPOSE: Our aim was to investigate the diagnostic accuracy of fluorine-18-labeled fluorodeoxyglucose positron emission tomography computed tomography (FDG-PET/CT) relative to CT for detecting neck lymph node metastases in patients with squamous cell carcinoma (SCC) of the hypopharynx, oropharynx, and larynx. METHODS: Thirty-four patients with SCC of the hypopharynx (n = 20), oropharynx (n = 5), and larynx (n = 9) who underwent neck dissection (29 bilateral, 5 unilateral; a total of 355 nodal levels) were assessed. Two observers determined the long-axis diameter and maximum standardized uptake value (SUVmax) of all visible neck nodes. Results of FDG-PET/CT were compared with those of corresponding histopathologic examinations according to the neck-level system. RESULTS: Histopathology revealed metastases in 70 of 355 nodal levels. Using a best discriminative SUVmax cutoff of 3.65, sensitivity, specificity, and accuracy of FDG-PET/CT on a level-by-level basis were 72.9, 96.8, and 92.1 %; those for CT were 52.9, 98.6, and 89.6 %. Differences in sensitivity and accuracy were significant (p < 0.01). The best cutoff SUVmax on the ipsilateral side was 4.61, with corresponding figures of 81.6, 100, and 94.7 %; that on the contralateral side was 2.41, with figures of 60, 88.4, and 85.4 %. CONCLUSION: FDG-PET/CT with SUVmax is useful for preoperative evaluation of neck-node metastasis from SCC of the pharynx and larynx, especially on the ipsilateral side.

Present and future role of FDG-PET/CT imaging in the management of head and neck carcinoma.

Integrated positron emission tomography/computed tomography (PET/CT) with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) is a useful technique for acquisition of both glucose metabolic and anatomic imaging data using a single device in a single diagnostic session, and has opened a new field in clinical oncologic imaging. FDG-PET/CT has been used successfully for the initial staging, restaging, monitoring of the response to therapy, and prognostication of head and neck carcinoma. The present review discusses the current role of FDG-PET/CT in the management of head and neck carcinoma, focusing on its usefulness and limitations for imaging in these patients.

Clinical significance of SUVmax in (18)F-FDG PET/CT scan for detecting nodal metastases in patients with oral squamous cell carcinoma.

To retrospectively investigate the diagnostic accuracy of FDG-PET/CT relative to CT for detection of cervical node metastases in patients with oral squamous cell carcinoma (OSCC), using histologic evaluation of dissected cervical nodes as the reference standard. Thirty-six patients with OSCC who underwent neck dissection (4 bilateral, 32 unilateral; 250 nodal levels) after FDG-PET/CT. Two observers consensually determined the lesion size and SUVmax of visible cervical nodes and compared the results with pathologic findings at the nodal level. Histopathology revealed nodal metastases in 13 (36.1 %) of 36 patients and 28 (11.2 %) of 250 nodal levels. Using a best discriminative SUVmax cut-off of 3.5 for the node, the sensitivity, specificity and accuracy of FDG-PET/CT for identification of nodal metastases on a level-by-level basis were 67.9, 94.6, and 91.6 %, respectively. The corresponding figures for CT were 42.9, 96.8, and 90.8 %, respectively. The sensitivity of FDG-PET/CT was significantly better than CT (p = 0.023). Moreover, using the level-based modified SUVmax cut-off, the respective figures for FDG-PET/CT were 71.4, 95.9, and 93.2 %, with significantly higher sensitivity (p = 0.013) and accuracy (p = 0.041) than CT. FDG PET/CT with SUVmax is a useful modality for preoperative evaluation of cervical neck lymph node metastases in patients with OSCC.

Role of diffusion weighted imaging and contrast-enhanced MRI in the evaluation of intrapelvic recurrence of gynecological malignant tumor.

BACKGROUND AND PURPOSE: To investigate the diagnostic performance of diffusion-weighted imaging (DWI) and contrast-enhanced imaging in combination with T2-weighted imaging (T2WI) for magnetic resonance imaging (MRI) evaluation of intrapelvic recurrence of gynecological malignancies. MATERIALS AND METHODS: Sixty-two patients with suspected intrapelvic recurrence of gynecological malignancies underwent pelvic MRI including T2WI DWI, and contrast-enhanced imaging. Diagnostic performance for detection of local recurrence, pelvic lymph node and bone metastases, and peritoneal lesions was evaluated by consensus reading of two experienced radiologists using a 5-point scoring system, and compared among T2WI with unenhanced T1-weighted imaging (T1WI) (protocol A), a combination of protocol A and DWI (protocol B), and a combination of protocol B and contrast-enhanced imaging (protocol C). Final diagnoses were obtained by histopathological examinations, radiological imaging and clinical follow-up for at least 6 months. Receiver operating characteristic (ROC) analysis and McNemar test were employed for statistical analysis. RESULTS: Locally recurrent disease, lymph node recurrence, peritoneal dissemination and bone metastases were present in 48.4%, 29.0%, 16.1%, and 6.5% of the patients, respectively. The patient-based sensitivity, specificity, accuracy, and area under the ROC curve (AUC) for detection of intrapelvic recurrence were 55.0, 81.8, 64.5% and 0.753 for protocol A, 80.0, 77.3, 79.0% and 0.838 for protocol B, and 80.0, 90.9, 83.9% and 0.862 for protocol C, respectively. The sensitivity, accuracy, and AUC were significantly better for protocols B and C than for protocol A (p<0.001). There was no significant difference between protocols B and C. CONCLUSION: MRI using a combination of DWI and T2WI gives comparatively acceptable results for assessment of intrapelvic recurrence of gynecological malignancies.

[Low methane concentration in the breath of Japanese].

A survey of breath methane excretion in Japanese is reported in this paper. The prevalence of methane excretion was 15% in 231 Japanese subjects, which was significantly lower than the range 33-60% reported in Canada and the USA. The prevalence of methane excretion was only 3% in males between the ages of 18-29 years old. However, it increased with age, and both males and females within the ages of 50-59 years old reached to almost the same value of 25-27%. When both parents were methane producers, 67% of their children were also methane producers. On the other hand, only 6% of the children were methane producers when both parents were methane non-producers. The prevalence of methane excretion was 55% in Caucasians who have lived in Japan for four years or longer. This is the same level reported in Canada and the USA. The effect of familial component and ethnic origin suggested that breath methane excretion is strongly affected by genetic factors.

Fusion of PET and MRI for staging of uterine cervical cancer: comparison with contrast-enhanced (18)F-FDG PET/CT and pelvic MRI.

PURPOSE: To investigate the fusion of pelvic magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (PET) for assessment of locoregional extension and nodal staging of cervical cancer. METHODS: PET/computed tomography (CT), MRI, and non-fused and fusion of PET and MRI for assessing the extent of the primary tumor and metastasis to nodes were evaluated. RESULTS: Accuracy for T-status was 83.3% for fused and non-fused PET/MRI and MRI proved significantly more accurate than PET/CT (53.3%) (P=.0077). Sensitivity, specificity, and accuracy for nodal metastasis were 92.3%, 88.2%, and 90.0% for fused PET/MRI and PET/contrast-enhanced CT; 84.6%, 94.1%, and 90.0% for non-fused PET/MRI; and 69.2%, 100%, and 86.7% for MRI. CONCLUSION: Fused PET/MRI combines the individual advantages of MRI and PET.

Value of fusion of PET and MRI in the detection of intra-pelvic recurrence of gynecological tumor: comparison with 18F-FDG contrast-enhanced PET/CT and pelvic MRI.

BACKGROUND: To evaluate the diagnostic value of retrospective image fusion from pelvic magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose positron emission tomography (PET) in detecting intra-pelvic recurrence of gynecological tumor. METHODS: Thirty patients with a suspicion of recurrence of gynecological malignancy underwent inline contrast-enhanced PET/computed tomography (CT) and pelvic contrast-enhanced MRI for restaging. Diagnostic performance about the local recurrence, pelvic lymph node and bone metastasis and peritoneal lesion of PET/low-dose non-enhanced CT (PET/ldCT), PET/full-dose contrast-enhanced CT (PET/ceCT), contrast-enhanced MRI, and retrospective image fusion from PET and MRI (fused PET/MRI) were evaluated by two experienced readers. Final diagnoses were obtained by histopathological examinations, radiological imaging and clinical follow-up for at least 6 months. McNemar test was employed for statistical analysis. RESULTS: Documented positive locally recurrent disease, pelvic lymph node and bone metastases, and peritoneal dissemination were present in 53.3, 26.7, 10.0, and 16.7%, respectively. Patient-based sensitivity for detecting local recurrence, pelvic lymph node and bone metastasis and peritoneal lesion were 87.5, 87.5, 100 and 80.0%, respectively, for fused PET/MRI, 87.5, 62.5, 66.7 and 60.0%, respectively, for contrast-enhanced MRI, 62.5, 87.5, 66.7 and 80.0%, respectively, for PET/ceCT, and 50.0, 87.5, 66.7 and 60.0%, respectively, for PET/ldCT. The sensitivity of diagnosing local recurrence by fused PET/MRI was significantly better than that of PET/ldCT (p=0.041). The patient-based sensitivity, specificity and accuracy for the detection of intra-pelvic recurrence/metastasis were 91.3, 100 and 93.3% for fused PET/MRI, 82.6, 100 and 86.7% for contrast-enhanced MRI, 82.6, 100 and 86.7% for PET/ceCT and 78.3, 85.7 and 80.0% for PET/ldCT. CONCLUSION: Fused PET/MRI combines the individual advantages of MRI and PET, and is a valuable technique for assessment of intra-pelvic recurrence of gynecological cancers.

Prognostic value of FDG PET imaging in patients with laryngeal cancer.

BACKGROUND AND PURPOSE: To investigate the prognostic value of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in patients with laryngeal cancer. MATERIALS AND METHODS: The study included 51 patients of whom 30 underwent definitive radiotherapy with or without chemotherapy and 21 underwent radical surgery with or without adjuvant chemoradiation therapy. FDG uptake by both the primary lesion and the neck node was measured using the maximum standardized uptake value (SUVmax). The effects of clinicopathological factors including primary tumor SUVmax and nodal SUVmax on progression-free survival, local control, nodal progression-free survival, and distant metastasis-free survival were evaluated using the log-rank test and Cox method. RESULTS: The median duration of follow-up was 48.6 months (range 8 to 82.1 months). Univariate analysis showed that nodal SUVmax, N status, and tumor TNM stage were significantly associated with recurrence, whereas primary tumor SUVmax, age, treatment strategy and T status were not. Multivariate analysis demonstrated that only the nodal SUVmax was a significantly unfavorable factor for progression-free survival (p = 0.029, hazard ratio 0.54, 95% CI 0.38-0.87) and nodal progression-free survival (p = 0.023, hazard ratio 0.51, 95% CI 0.34-0.81). ROC curve analysis and log-rank test showed that patients with a high nodal SUVmax (≧ 4) had a significantly lower progression-free survival rate than those with a low SUVmax (<4; p<0.0001). CONCLUSIONS: The pretreatment SUVmax of nodal disease in patients with laryngeal cancer is prognostic for recurrence.

¹8F-FDG-PET/CT findings of retroperitoneal tumors: a pictorial essay.

A variety of different tumors can arise from any of the tissues present in the retroperitoneum, and they exhibit a wide range of pathologic types. Although computed tomography (CT) and magnetic resonance imaging (MRI) can demonstrate important characteristics of these tumors, diagnosis is often challenging for radiologists. The purpose of this pictorial essay is to review (18)F-fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) features of different kinds of benign and malignant retroperitoneal tumors in comparison with CT or MRI findings alone and to become familiar with the wide variety of imaging characteristics.

Value of fusion of PET and MRI for staging of endometrial cancer: comparison with ¹8F-FDG contrast-enhanced PET/CT and dynamic contrast-enhanced pelvic MRI.

PURPOSE: To investigate the diagnostic value of retrospective fusion of pelvic MRI and (18)F-fluorodeoxyglucose ((18)F-FDG) PET images for assessment of locoregional extension and nodal staging of endometrial cancer. MATERIALS AND METHODS: Thirty patients with biopsy-proven endometrial cancer underwent preoperative contrast-enhanced PET/CT (PET/ceCT) and pelvic dynamic contrast-enhanced MRI for initial staging. Diagnostic performance of PET/ceCT, contrast-enhanced MRI, and retrospective image fusion from PET and MRI (fused PET/MRI) for assessing the extent of the primary tumor (T stage) and metastasis to regional LNs (N stage) was evaluated by two experienced readers. Histopathological and follow-up imaging results were used as the gold standard. The McNemar test was employed for statistical analysis. RESULTS: Fused PET/MRI and MRI detected 96.7% of the primary tumors, whereas PET/ceCT detected 93.3%. Accuracy for T status was 80.0% for fused PET/MRI, and MRI proved significantly more accurate than PET/ceCT, which had an accuracy of 60.0% (p=0.041). Patient-based sensitivity, specificity and accuracy for detecting pelvic nodal metastasis were 100%, 96.3% and 96.7% for both fused PET/MRI and PET/ceCT, and 66.7%, 100% and 96.7% for MRI, respectively. These three parameters were not statistically significant (p=1). CONCLUSION: Fused PET/MRI, which complements the individual advantages of MRI and PET, is a valuable technique for assessment of the primary tumor and nodal staging in patients with endometrial cancer.

Respiratory-gated ¹8F-FDG PET/CT for the diagnosis of liver metastasis.

PURPOSE: To ascertain the role of respiratory-gated PET/CT with (18)F-fluorodeoxyglucose ((18)F-FDG) for accurate diagnosis of liver metastasis. MATERIALS AND METHODS: Forty patients with suspected liver metastasis underwent conventional whole-body PET/CT scan initially, followed by respiratory-gated PET/CT scan covering the liver. Visual detectability (using a 5-point confidence scale), maximum standardized uptake value (SUVmax) and metabolic tumor volume (MTV) of hepatic metastatic lesions were assessed for three data sets including ordinary whole-body (WB) scan, and non-respiratory-gated (nRG) and respiratory-gated (RG) scans. Results of enhanced CT and/or MRI, or clinical and radiological follow-up were used for reference. RESULTS: Sixteen of the patients were found to have 53 metastatic lesions in the liver. Patient-based accuracy of WB, nRG, and RG was 92.5%, 95.0%, and 97.5%, respectively, with a lesion-based detection rate of 67.9%, 73.6%, and 73.6%, respectively. The average SUVmax of 34 liver metastatic lesions for WB, nRG, and RG was 6.60 ± 2.34, 7.19 ± 2.66, and 8.08 ± 3.24, respectively. SUVmax for RG was significantly higher than that for WB (p=0.0069). The average MTV of these 40 lesions for the three protocols was 5.32 ± 4.78 cm(3), 5.07 ± 4.73 cm(3), and 4.73 ± 4.67 cm(3), respectively. Among the three protocols, RG showed the best visual and quantitative evaluation for diagnosis of liver metastasis. CONCLUSION: Respiratory-gated PET/CT allows more accurate identification of liver metastases than non-respiratory-gated PET/CT.

Value of retrospective image fusion of ¹8F-FDG PET and MRI for preoperative staging of head and neck cancer: comparison with PET/CT and contrast-enhanced neck MRI.

PURPOSE: To assess the clinical value of retrospective image fusion of neck MRI and (18)F-fluorodeoxyglucose ((18)F-FDG) PET for locoregional extension and nodal staging of neck cancer. MATERIALS AND METHODS: Thirty patients with carcinoma of the oral cavity or hypopharynx underwent PET/CT and contrast-enhanced neck MRI for initial staging before surgery including primary tumor resection and neck dissection. Diagnostic performance of PET/CT, MRI, and retrospective image fusion of PET and MRI (fused PET/MRI) for assessment of the extent of the primary tumor (T stage) and metastasis to regional lymph nodes (N stage) was evaluated. RESULTS: Accuracy for T status was 87% for fused PET/MRI and 90% for MRI, thus proving significantly superior to PET/CT, which had an accuracy of 67% (p=0.041 and p=0.023, respectively). Accuracy for N status was 77% for both fused PET/MRI and PET/CT, being superior to MRI, which had an accuracy of 63%, although the difference was not significant (p=0.13). On a per-level basis, the sensitivity, specificity and accuracy for detection of nodal metastasis were 77%, 96% and 93% for both fused PET/MRI and PET/CT, compared with 49%, 99% and 91% for MRI, respectively. The differences for sensitivity (p=0.0026) and accuracy (p=0.041) were significant. CONCLUSION: Fused PET/MRI combining the individual advantages of MRI and PET is a valuable technique for assessment of staging neck cancer.