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

Purpose  The 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 methods  Forty 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. Results  Staging 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. Conclusion  Integrated FDG-PET/contrast-enhanced CT is a more accurate imaging modality for staging ovarian cancer and useful for selecting appropriate treatment than enhanced CT.     

Whole-body MRI for initial staging of paediatric lymphoma: prospective comparison to an FDG-PET/CT-based reference standard

Objective

To compare whole-body MRI, including diffusion-weighted imaging (whole-body MRI-DWI), with FDG-PET/CT for staging newly diagnosed paediatric lymphoma.

Methods

A total of 36 children with newly diagnosed lymphoma prospectively underwent both whole-body MRI-DWI and FDG-PET/CT. Whole-body MRI-DWI was successfully performed in 33 patients (mean age 13.9 years). Whole-body MRI-DWI was independently evaluated by two blinded observers. After consensus reading, an unblinded expert panel evaluated the discrepant findings between whole-body MRI-DWI and FDG-PET/CT and used bone marrow biopsy, other imaging data and clinical information to derive an FDG-PET/CT-based reference standard.

Results

Interobserver agreement of whole-body MRI-DWI was good [all nodal sites together (κ = 0.79); all extranodal sites together (κ = 0.69)]. There was very good agreement between the consensus whole-body MRI-DWI- and FDG-PET/CT-based reference standard for nodal (κ = 0.91) and extranodal (κ = 0.94) staging. The sensitivity and specificity of consensus whole-body MRI-DWI were 93 % and 98 % for nodal staging and 89 % and 100 % for extranodal staging, respectively. Following removal of MRI reader errors, the disease stage according to whole-body MRI-DWI agreed with the reference standard in 28 of 33 patients.

Conclusions

Our results indicate that whole-body MRI-DWI is feasible for staging paediatric lymphoma and could potentially serve as a good radiation-free alternative to FDG-PET/CT.

Keypoints

? Accurate staging is important for treatment planning and assessing prognosis ? Whole-body MRI-DWI could be a good radiation-free alternative to FDG-PET/CT ? Interobserver agreement of whole-body MRI-DWI is good ? Agreement between whole-body MRI and the FDG-PET/CT reference standard is good ? Most discrepancies were caused by suboptimal accuracy of size measurements on MRI     

Whole-body magnetic resonance imaging and FDG-PET/CT for lymphoma staging: Assessment of patient experience

Purpose

To compare patient experience of whole-body MRI and FDG-PET/CT performed for lymphoma staging.

TNM staging with FDG-PET/CT in patients with primary head and neck cancer

Purpose PET/CT, PET+CT, and CT were compared concerning accuracies in TNM staging and malignancy detection in head and neck cancer. The impact of PET/CT compared to the other imaging modalities on therapy management was assessed. Materials and methods Fifty-five patients with suspected head and neck primary cancer underwent whole-body FDG-PET/CT. PET/CT and PET+CT were evaluated by a nuclear medicine physician and a radiologist; CT was evaluated by two radiologists, PET by two nuclear physicians. Histopathology served as the standard of reference. Differences between the staging modalities were tested for statistical significance by McNemar’s test. Results Overall TNM-staging and T-staging with PET/CT were more accurate than PET+CT and CT alone (p < 0.05). PET/CT was marginally more accurate than CT alone in N-staging (p = 0.04); no statistically significant difference was found when compared to PET+CT for N-staging. PET/CT altered further treatment in 13 patients compared to CT only and in 7 patients compared to PET+CT. Conclusion Combined PET/CT proved to be partly more accurate in assessing the overall TNM-stage than CT and PET+CT. These results were based on a higher accuracy concerning the T-stage, mainly in patients with metallic implants and marginally the N-stage. Therapy decisions have been influenced in a substantial number of patients. PET/CT might be considered as a first line diagnostic tool in patients with suspected primary head and neck cancer.     

Whole-body MRI for the detection of bone marrow involvement in lymphoma: prospective study in 116 patients and comparison with FDG-PET

Objective

To assess and compare the value of whole-body MRI with FDG-PET for detecting bone marrow involvement in lymphoma.

Methods

A total of 116 patients with newly diagnosed lymphoma prospectively underwent whole-body MRI and blind bone marrow biopsy (BMB) of the posterior iliac crest. Of 116 patients, 80 also underwent FDG-PET. Patient-based sensitivities of whole-body MRI for detecting bone marrow involvement were calculated using BMB as reference standard and compared with FDG-PET in aggressive and indolent lymphomas separately.

Results

Sensitivity of whole-body MRI in all lymphomas was 45.5 % [95 % confidence interval (CI): 29.8–62.0 %]. Sensitivity of whole-body MRI in aggressive lymphoma [88.9 % (95 % CI: 54.3–100 %)] was significantly higher (P?=?0.0029) than that in indolent lymphoma [23.5 % (95 % CI: 9.1–47.8 %)]. Sensitivity of FDG-PET in aggressive lymphoma [83.3 % (95 % CI: 41.8–98.9 %)] was also significantly higher (P?=?0.026) than that in indolent lymphoma [12.5 % (95 % CI: 0–49.2 %)]. There were no significant differences in sensitivity between whole-body MRI and FDG-PET (P?=?1.00)

Conclusion

Sensitivity of whole-body MRI for detecting lymphomatous bone marrow involvement is too low to (partially) replace BMB. Sensitivity of whole-body MRI is significantly higher in aggressive lymphoma than in indolent lymphoma and is equal to FDG-PET in both entities.

Key Points

? Bone marrow involvement in lymphoma has prognostic and therapeutic implications. ? Blind bone marrow biopsy (BMB) is standard for bone marrow assessment. ? Neither whole-body MRI nor FDG-PET can yet replace BMB. ? Both techniques have higher sensitivity in aggressive than in indolent lymphoma. ? Both imaging techniques are complementary to BMB.     

Whole-body MRI and PET/CT in multiple myeloma patients during staging and after treatment: personal experience in a longitudinal study

Purpose

Diagnostic imaging plays a pivotal role in staging and prognostic assessment of multiple myeloma (MM) as well as planning and monitoring treatment. The aim of our study was to estimate the diagnostic accuracy of wholebody magnetic resonance imaging (WB-MRI) and positron emission tomography/computed tomography (PET/CT) in MM patients studied before and after treatment.

Materials and methods

We considered 22 consecutive patients (10 males, 12 females; age range, 48–83 years) with newly diagnosed MM (NDMM group), and the same 22 patients underwent at least one re-assessment after treatment (previously treated MM, PTMM group). WBMRI and PET/CT were performed within days from each other in both the NDMM (22 studies) and PTMM (29 studies) group. The imaging findings were compared to the results of bone marrow aspiration.

Results

PET/CT was positive in 18/22 NDMM patients, whereas WB-MRI correctly identified 100% of patients. Of 20 responder patients in the PTMM group, 16 were negative at PET/CT and 12/20 at MRI. By contrast, of the nine nonresponder patients, MRI correctly detected active disease in all cases, and PET only in seven.

Conclusions

WB-MRI proved superior to PET/CT in detecting MM, especially in diffuse disease. PET/CT appears to be more sensitive in the assessment of MM after treatment.     

Whole-body MRI including diffusion-weighted imaging (DWI) for patients with recurring prostate cancer: technical feasibility and assessment of lesion conspicuity in DWI

Purpose:

To evaluate the principal methodological aspects of whole‐body magnetic resonance imaging (MRI) including diffusion‐weighted imaging (DWI) with background suppression using a time‐optimized protocol for restaging of prostate cancer patients in a technical feasibility study.

Materials and Methods:

Seventeen patients underwent MRI at 1.5T from the base of the skull to the proximal thigh using axial T1‐weighted (T1w), T2w short‐tau inversion recovery (STIR), and DWI (b‐values: 50 and 500 s/mm²) and sagittal T1w and T2w STIR of the spine. Apparent diffusion coefficient (ADC) values of liver, spleen, kidney, muscle, and bone were measured. Image quality in DWI was assessed by using a scale from 0–9. Contrast‐to‐noise ratios (CNRs) of lymph node and bone metastases were determined in T1w, T2w STIR, and DWI. Bone metastases were further subclassified according to their Hounsfield units (HU) in computed tomography (CT).

Results:

Mean acquisition and mean room times were 66:20 and 75:21 minutes, respectively. ADC values of normal organs showed good concordance with reported data. Good to excellent image quality was observed for DWI (mean scores 7.41–8.00) with the exception of the neck (mean score 4.76). CNR of DWI (b‐value 50 s/mm²) for lymph node metastases was clearly superior compared to all other sequences. For bone metastases T1w performed significantly better for sclerotic lesions (HU > 600), DWI (b‐value 50 s/mm²) for nonsclerotic lesion (HU < 300).

Conclusion:

In patients with recurrent prostate cancer a whole‐body MR protocol including DWI is technically robust. Due to the high CNR of DWI compared to T1w and T2w STIR, detection of malignant lesions should be facilitated by DWI, except for sclerotic bone metastases. J. Magn. Reson. Imaging 2011;33:1160–1170. © 2011 Wiley‐Liss, Inc.     

Whole-body MRI for the staging and follow-up of patients with metastasis

The advent of whole-body MRI (WB-MRI) has introduced tumor imaging with a systemic approach compared to established sequential, multi-modal diagnostic algorithms. Hardware innovations, such as the introduction of multi-receiver channel whole-body scanners at 1.5 T and recently 3 T, combined with acquisition acceleration techniques, have made high resolution WB-MRI clinically feasible. Now, a dedicated assessment of individual organs with various soft tissue contrast, spatial resolution and contrast media dynamics can be combined with whole-body anatomic coverage in a multi-planar imaging approach. More flexible protocols, e.g. including T1-weighted TSE- and STIR-imaging, dedicated lung imaging or dynamic contrast-enhanced studies of the abdomen can be performed within less than 45 min.For initial tumor staging PET-CT as a competing whole-body modality in oncologic imaging has proved more accurate for the definition of T-stage and lymph node assessment, using the additional metabolic information of PET for the assessment of tumor viability and therapy response. However, new applications, such as MR-whole-body diffusion imaging, may significantly increase sensitivity in near future. WB-MRI has shown advantages for the detection of distant metastatic disease, especially from tumors frequently spreading to the liver or brain and it is especially useful as a radiation-free alternative for the surveillance of tumor patients with multiple follow-up exams. Furthermore, it has been introduced as a whole-body bone marrow screening application. Within this context WB-MRI is highly accurate for the detection of skeletal metastases and staging of hematologic diseases, such as multiple myeloma or lymphoma. This article summarizes recent developments and applications of WB-MRI and highlights its performance within the scope of systemic oncologic staging and surveillance.     

Psoas muscle metastasis from cervical carcinoma: Correlation and comparison of diagnostic features on FDG-PET/CT and diffusion-weighted MRI

Psoas muscle metastasis, though rare, is the commonest site of skeletal muscle involvement in cervical carcinoma. The appropriate clinical management of this condition, particularly of the pain related to malignant psoas syndrome, is still evolving and the diagnostic features on conventional morphological imaging modalities are often non specific, with the differential diagnosis lying between sarcoma, hematoma, and abscess. In this report, a comparison of various morphofunctional imaging modalities was made. Fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) was the first to suspect disease involvement of the psoas muscle, demonstrating intense FDG uptake (compared with the contralateral muscle), while ultrasound showed heterogeneous echotexture, and magnetic resonance imaging (MRI) showed subtle altered signal intensity in the right psoas muscle. Both anatomical imaging modalities and non contrast CT of the PET-CT examination demonstrated a bulky psoas muscle, without any focal abnormality. On diffusion-weighted imaging of MRI (DWI-MRI), restricted diffusion of the involved muscle was an important observation. The psoas muscle metastatic involvement was proven histopathologically. Thus, enhanced glucose metabolism and restricted diffusion in the newer non-invasive molecular imaging modalities (e.g., PET/CT and DWI-MRI) could serve as valuable adjunctive parameters in diagnosing this entity in the absence of a focal abnormality in the anatomical modalities. In the treatment response monitoring scenario, FDG-PET/CT demonstrated near complete resolution following administration of 3 cycles of systemic chemotherapy and local external radiotherapy.     

FDG-PET/CT in restaging of patients with recurrent breast cancer: possible impact on staging and therapy

We aimed to compare the value of combined positron emission tomography (PET)/CT, PET+CT (viewed side by side), CT alone and PET alone concerning the rTNM stage and influence on therapy in patients with recurrent breast cancer. 44 patients with suspicion of recurrent breast cancer underwent whole-body [18F]-2-fluoro-2-deoxy-d-glucose (FDG)-PET/CT. Images of combined PET/CT, PET+CT, PET alone and CT alone were evaluated by four blinded reader teams. Diagnostic accuracies and influence on therapy were compared. Histology and a mean clinical follow up of 456 days served as the standard of reference. Differences between the staging procedures were tested for statistical significance by McNemar's test. Overall TNM tumour stage was correctly determined in 40/44 patients with PET/CT, in 38/44 with PET+CT, in 36/44 with PET alone and in 36/44 patients with CT alone. No statistically significant difference was detected between all tested imaging modalities. PET/CT changed the therapy in two patients compared with PET+CT, in four patients compared with PET alone and in five patients compared with CT alone. Combined PET/CT appeared to be more accurate in assessing the rTNM and showed a moderate impact on therapy over PET and CT. Minor improvements were noted when compared with PET+CT. Experienced readers might therefore be able to provide accurate staging results for further therapy from separately acquired studies.     

Contrast-enhanced FDG-PET/CT vs. SPIO-enhanced MRI vs. FDG-PET vs. CT in patients with liver metastases from colorectal cancer: a prospective study with intraoperative confirmation

BACKGROUND: The choice of imaging before liver surgery is debated regarding the use of magnetic resonance (MR) imaging, computed tomography (CT), and positron emission tomography (PET). No studies have compared contrast-enhanced PET/CT with superparamagnetic iron oxide (SPIO)-enhanced MR imaging. PURPOSE: To compare PET/CT with superparamagnetic iron oxide (SPIO)-enhanced MR imaging, PET, and CT in the detection of liver metastases (LM) and extrahepatic tumor from colorectal cancer (CRC). MATERIAL AND METHODS: Thirty-five patients with suspected LM underwent PET/CT with a contrast-enhanced CT protocol and SPIO-enhanced MR imaging. Readers independently analyzed images from MR imaging, PET/CT, and the CT part and PET part of the PET/CT study. Imaging findings were compared with surgical and histological findings. RESULTS: Lesion-by-lesion sensitivity and accuracy for liver lesions was 54% and 77% for PET alone, 66% and 83% for PET/CT, 82% and 82% for SPIO-enhanced MR imaging, and 89% and 77% for CT alone, respectively. CT and SPIO-enhanced MR imaging were less specific but significantly more sensitive than PET (P<0.0001). For extrahepatic tumor, sensitivity and specificity was 83% and 96% for PET/CT and 58% and 87% for CT, respectively. CONCLUSION: CT and SPIO-enhanced MR imaging are more sensitive but less specific than PET in the detection of LM. PET/CT can detect more patients with extrahepatic tumor than CT alone.     

Present and future of FDG-PET/CT in ovarian cancer

Integrated FDG-PET/CT has been used successfully for the diagnosis, staging, restaging, therapy monitoring and prognostic prediction of ovarian cancer as well as various other malignant tumors. Compared with conventional PET/non-contrast CT images, combined PET/contrast-enhanced CT images with intravenous iodine contrast medium and sufficient radiation dose may contribute to a more accurate diagnosis with higher confidence. In the future, tracers other than FDG and integrated PET/MRI will be realized. We herein review the place and role of FDG-PET/CT in the management of ovarian cancer, discussing its usefulness and limitations in the imaging of these patients.     

Detection of recurrent ovarian cancer at MRI: comparison with integrated PET/CT

OBJECTIVE: To compare the diagnostic performances of magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) for the detection of recurrent ovarian tumor. METHODS: Thirty-six patients who underwent primary cytoreductive surgery for ovarian carcinoma received both MRI and PET/CT for the evaluation of ovarian tumor recurrence. Recurrent ovarian tumors in abdomen and pelvis were classified based on site as follows: (1) local pelvic recurrence, (2) peritoneal lesion, (3) lymph nodal metastasis, and (4) distant metastasis. Patient-based and lesion-based analyses were retrospectively performed with the aim of detecting tumor recurrence. For the detection of recurrent ovarian tumors, we compared patient-based and lesion-based diagnostic accuracies of these 2 modalities using the McNemar test. RESULTS: Histopathologic, clinical, and radiological follow-up findings revealed recurrent ovarian tumors in 35 sites of 22 patients. These 35 sites consisted of local pelvic recurrence (n = 15), peritoneal lesions (n = 14), lymph nodal metastasis (n = 4), and abdominal wall metastasis (n = 2). In detecting recurrent ovarian tumor, patient-based sensitivity and the accuracy of PET/CT and MRI were 73% and 91% (P < 0.05), and 81% and 89% (P > 0.05), respectively. In addition, overall lesion-based sensitivity of PET/CT and MRI were 66% and 86%, respectively (P < 0.05). In detecting peritoneal lesions, overall lesion-based sensitivity and accuracy of PET/CT and MRI for peritoneal lesions were 43% and 86%, and 75% and 94%, respectively (P < 0.05). CONCLUSIONS: Magnetic resonance imaging is more sensitive than PET/CT for detecting local pelvic recurrence and peritoneal lesions of recurrent ovarian tumors.     

Whole-body FDG-PET imaging in the management of patients with cancer

Fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging is increasingly used for the management of patients with cancer. The technique is now well accepted by most physicians as an effective complement to the existing imaging modalities. For many malignancies, PET achieves high sensitivity and specificity. The critical role of this powerful technique is realized increasingly in the day-to-day practice of oncology. This is particularly true for the management of patients with non-small-cell lung cancer (NSCLC). The contribution of PET for the selection of patients eligible for curative treatments in this setting is well established. Convincing data also exist to support the use of PET for evaluating patients with recurrent colorectal carcinoma, for staging and restaging lymphomas, and for diagnosing recurrent thyroid carcinoma in the presence of elevated thyroglobulin and negative 131I scans. Other indications include staging of various recurrent malignancies, such as breast cancer, melanoma, and head and neck and gynecologic carcinomas. Existing data are limited for the determination of the impact of PET in certain malignancies, and further studies, which should include outcome information, will allow clarification of the role of this modality for such indications. Despite the small number of studies specifically designed to assess changes in management plans for some malignancies after performing PET the overall favorable results are encouraging enough at this time to include this modality as an essential element of the practice of modern oncology. Finally, the evolving role of PET imaging as a predictor of response after local or systemic treatment may add a major dimension to the application of this novel technique.