Non-small cell lung cancer: whole-body MR examination for M-stage assessment--utility for whole-body diffusion-weighted imaging compared with integrated FDG PET/CT

Diffusion-weighted MR imaging in comparison to integrated [¹⁸F]-FDG PET/CT for N-staging in patients with lung cancer

PURPOSE

The purpose of this study was to prospectively determine the diagnostic accuracy of diffusion-weighted imaging (DWI) using MRI in the staging of thoracic lymph nodes in patients with lung cancer, and to compare the performance to that of PET/CT.

PATIENTS AND METHOD

20 consecutive patients (pts) with histologically proven lung cancer were included in this study. In all pts FDG-PET/CT was routinely performed to stage lung carcinoma. Additionally, MRI (1.5T) was performed including native T1w, T1w post contrast medium, T2w, and DWI sequences. Regarding the N stage based on the results of the PET/CT there were 5 patients with N0, 3 patients with N1, 5 patients with N2 and 7 patients with N3. Image analysis was performed by two radiologists (R1 and R2), respectively. The reviewers had to chose between 1 (at least one lymph node within a station is malignant) or 0 (no lymph nodes suspicious for malignancy). First the T1 post contrast sequence was analyzed. In a second step the DWI sequence (b=800) was analyzed. Both steps were performed in a blinded fashion.

RESULTS

MR imaging with or without DWI only agreed with the results of the PET/CT regarding the N stage in 80% of the patients-15% were understaged and 5% overstaged. There was excellent interobserver agreement; the N-staging result only differed in 1 patient for DWI, resulting in correlation coefficients of 0.98 for DWI and 1.0 for MRI. Compared to PET-CT MRI overstaged one and understaged 4 patients, while DWI overstaged one and understaged 3 patients. This resulted in correlation coefficients of 0.814 (R1 and R2) for MRI and 0.815 (R1) and 0.804 (R2) for DWI. Regarding the ADC values there were no significant differences between ipsilateral hilar (1.03 mm(2)/s ± 0.13), subcarinal (0.96 mm(2)/s±0.24), ipsilateral mediastinal (1.0mm(2)/s ± 0.18), contralateral mediastinal (0.93 mm(2)/s ± 0.23) and supraclavicular (0.9 mm(2)/s ± 0.23) lymph nodes.

CONCLUSION

Diffusion-weighted imaging does not show a clear advantage over conventional MR protocols in the N-staging of lung cancer. MRI with or without DWI shows a moderately correlation with PET/CT with a tendency for understaging.

Whole-body diffusion-weighted imaging in lymphoma

The current evidence regarding the usefulness of whole-body diffusion-weighted magnetic resonance imaging (DWI) in lymphoma is reviewed. DWI is capable of combining anatomical and functional information and is becoming a valuable tool in oncology, in particular for staging purposes. DWI may prove to be a useful biomarker in clinical decision making for patients with lymphoma. Large-scaled prospective studies are needed to confirm these preliminary results.

Complementary roles of whole-body diffusion-weighted MRI and 18F-FDG PET: the state of the art and potential applications

(18)F-FDG PET is an established functional imaging modality for the evaluation of human disease. Diffusion-weighted MRI (DWI) is another rapidly evolving functional imaging modality that can be used to evaluate oncologic and nononcologic lesions throughout the body. The information provided by (18)F-FDG PET and DWI can be complementary, because the 2 methods are based on completely different biophysical underpinnings. This article will describe the basic principles, clinical applications, and limitations of DWI. In addition, the available evidence that correlates and compares (18)F-FDG PET and DWI will be reviewed.

[What is the role of FDG-PET in thoracic oncology in 2010?]

18F-Fluorodeoxyglucose-Positron Emission Tomography (FGD-PET) has been considered to have a major impact on the management of lung malignancies since the beginning of this century. Its value has been demonstrated by many publications, meta-analysis and European/American/Japanese recommendations. PET combined with computed tomography has provided useful information regarding the diagnosis and staging of lung cancer and allows for the delivery of adaptive radiotherapy. In its more common uses, PET has been shown to be cost-effective. With the widespread use of new radiotracers, PET will play an increasing role in the evaluation of response to treatment.

Diagnostic accuracy of whole-body MRI/DWI image fusion for detection of malignant tumours: a comparison with PET/CT

OBJECTIVE

To prospectively evaluate the diagnostic accuracy of whole-body T2-weighted (wbT2), whole-body diffusion-weighted imaging (wbDWI) and wbT2/wbDWI image fusion for malignant tumour detection compared with PET/CT.

METHODS

Sixty-eight patients (44 men; 60 ± 14 years) underwent PET/CT for staging of malignancy and were consecutively examined by 1.5-Tesla MRI including wbT2 and wbDWI. Two radiologists independently assessed wbDWI, wbT2, wbT2 + wbDWI (side-by-side) and wbT2 + wbDWI + wbT2/wbDWI image fusion for the presence of malignancy. PET/CT served as a reference standard.

RESULTS

PET/CT revealed 374 malignant lesions in 48/64 (75%) patients. Detection rates and positive predictive value (PPV) of wbT2 and wbDWI alone were 64% and 84%, and 57% and 93%, respectively. Detection rates and PPV of wbT2 and wbDWI for side-by-side analysis without and with fused images were 72% and 89%, and 74% and 91%, respectively. The detection rate was significantly higher with side-by-side analysis and fused image analysis compared with wbT2 and wbDWI alone (p = .0159; p < .0001). There was no significant difference between fused image interpretation and side-by-side analysis.

CONCLUSIONS

WbDWI allows detection of malignant lesions with a similar detection rate to wbT2. Side-by-side analysis of wbT2 and wbDWI significantly improves the overall detection rate and fused image data provides no added value.

Cancer imaging: novel concepts in clinical magnetic resonance imaging

Cancer is a major public health problem in the Western world. Imaging is of crucial importance in oncology, because it may reduce cancer-related morbidity and mortality. To improve tumour evaluation, there is a need for functional imaging modalities that go beyond gross assessment of anatomical abnormalities and allow visualization and quantification of biochemical processes in vivo. Magnetic resonance imaging (MRI) not only provides anatomical information, but also offers a wide range of functional sequences that may aid the evaluation of cancerous lesions. Furthermore, MRI provides the opportunity to guide and monitor anticancer therapies noninvasively. The aim of this review is to highlight some of the most promising developments of MRI in the functional assessment of cancer and the guidance and monitoring of (novel) anticancer therapies.

Differential diagnosis of mammographically and clinically occult breast lesions on diffusion-weighted MRI

PURPOSE

To investigate the diagnostic performance of diffusion-weighted imaging (DWI) for mammographically and clinically occult breast lesions.

MATERIALS AND METHODS

The study included 91 women with 118 breast lesions (91 benign, 12 ductal carcinoma in situ [DCIS], 15 invasive carcinoma) initially detected on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and assigned BI-RADS category 3, 4, or 5. DWI was acquired with b = 0 and 600 s/mm(2). Lesion visibility was assessed on DWI. Apparent diffusion coefficient (ADC) values were compared between malignancies, benign lesions, and normal (no abnormal enhancement on DCE-MRI) breast tissue, and the diagnostic performance of DWI was assessed based on ADC thresholding.

RESULTS

Twenty-four of 27 (89%) malignant and 74/91 (81%) benign lesions were hyperintense on the b = 600 s/mm(2) diffusion-weighted images. Both DCIS (1.33 +/- 0.19 x 10(-3) mm(2)/s) and invasive carcinomas (1.30 +/- 0.27 x 10(-3)mm(2)/s) were lower in ADC than benign lesions (1.71 +/- 0.43 x 10(-3)mm(2)/s; P < 0.001), and each lesion type was lower in ADC than normal tissue (1.90 +/- 0.38 x 10(-3)mm(2)/s, P <or= 0.001). Receiver operating curve (ROC) analysis showed an area under the curve (AUC) of 0.77, and sensitivity = 96%, specificity = 55%, positive predictive value (PPV) = 39%, and negative predictive value (NPV) = 98% for an ADC threshold of 1.60 x 10(-3)mm(2)/s.

CONCLUSION

Many mammographically and clinically occult breast carcinomas were visibly hyperintense on diffusion-weighted images, and ADC enabled differentiation from benign lesions. Further studies evaluating DWI while blinded to DCE-MRI are necessary to assess the potential of DWI as a noncontrast breast screening technique.

Multiplexed imaging in cancer diagnosis: applications and future advances

The development of imaging technologies that have sufficient specificity and sensitivity to enable early, accurate detection of cancer and response to therapy has long been a goal in oncology. Various radiological techniques have been used for diagnosis and surveillance of disease recurrence and imaging has revolutionised oncology. However, despite the widespread use of technologies, the ability of currently available imaging methods to facilitate early detection, precise characterisation, and accurate localisation of malignant disease could be improved. The simultaneous use of two or more techniques, contrast reagents, signalling methods, or the coupling of agent and tissue properties to achieve so-called multiplexed imaging is a promising approach. In this review, we provide a broad overview of current and emerging multiplexed, imaging technologies.

Whole-body diffusion-weighted imaging vs. FDG-PET for the detection of non-small-cell lung cancer. How do they measure up?

OBJECTIVE

To compare the diagnostic efficacy of whole-body diffusion-weighted imaging (WB-DWI) and [18F] fluoro-2-D-glucose PET/CT(FDG-PET/CT)for assessment of non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

A group of 56 patients (21 female, 35 male; 35-76 years) with NSCLC proved by pathologic examination or follow-up imaging findings was set as reference standards, and all patients underwent both WB-DWI at 1.5T (MAGNETOM Avanto) and PET/CT (Biograph 16). For WB-DWI, a free breathing diffusion-weighted single-shot spin-echo epi-sequence in five-stations (head-neck, thorax, abdomen, pelvis-thigh) was used. Each station-series contained 30 contiguous axial slices. Imaging parameters: FOV 360x360 mm, matrix size 128x80. B-values: 0 and 1000 s/mm(2) applied along x, y and z, 5 averages, acquisition time: 2.23 min/series, total: 11.55 min. The efficacy of WB-DWI and PET/CT were determined in a blinded reading by two radiologists and two nuclear medicine physicians using pathology and size change during follow up exams as the reference standard.

RESULTS

Primary tumors (n=56 patients) were correctly detected in 56 (100%) patients by both PET/CT and WB-DWI. Ninety-six lymph nodes metastases were determined with pathologic and follow-up examinations. Sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV) being for lymph node metastases: 91%, 90%, 90%, 96%, 80% with WB-DWI and 98%, 97%, 97%, 99%, 93% with PET-CT, other metastases: 90%, 95%, 92%, 97%, 83% with WB-DWI and 98%, 100%, 98%, 100%, 95% with PET-CT). Differences in the accuracy of lymph node metastasis detection between PET/CT and WB-DWI (P=.031) were significant. The differences were not statistically significant for detection of other metastases.

CONCLUSIONS

WB-DWI is a feasible clinical technique for the assessment of NSCLC, lymph nodes and metastastic spread with high sensitivity and accuracy, but it was limited in the evaluation of neck lymph node metastases and small metastastic lung nodules.

Comparison of diffusion-weighted whole body MRI and skeletal scintigraphy for the detection of bone metastases in patients with prostate or breast carcinoma

PURPOSE

To prospectively compare the diagnostic accuracy of diffusion-weighted whole body imaging with background whole body signal suppression (DWIBS) with skeletal scintigraphy for the diagnosis and differentiation of skeletal lesions in patients suffering from prostate or breast cancer.

MATERIAL AND METHODS

A diagnostic cohort of 36 patients was included in skeletal scintigraphy and 1.5 T DWIBS MRI. Based on morphology and signal intensity patterns, two readers each identified and classified independently, under blinded conditions, all lesions into three groups: (1) malignant, (2) unclear if malignant or benign and (3) benign. Finally, for the definition of the gold standard all available imaging techniques and follow-up over a minimum of 6 months were considered.

RESULTS

Overall, 45 circumscribed bone metastases and 107 benign lesions were found. DWIBS performed significantly better in detecting malignant skeletal lesions in patients with more than 10 lesions (sensitivity: 0.97/0.91) compared to skeletal scintigraphy (sensitivity: 0.48/0.42). No statistical difference could be found between DWIBS (0.58/0.33) and skeletal scintigraphy (0.67/0.58) in the sensitivity values for malignant skeletal lesions in patients with less than 5 lesions. For benign lesions, scintigraphy scored best with a sensitivity of 0.93/0.87 compared to 0.20/0.13 for DWIBS. Interobserver agreement with Cohen's kappa coefficient was calculated as 0.784 in the case of scintigraphy and 0.663 for DWIBS.

CONCLUSION

With respect to staging, in prostate and breast carcinoma, the DWIBS technique is not superior to skeletal scintigraphy, but ranks equally. However, in the cases with many bone lesions, markedly more metastases could be discovered using the DWIBS technique than skeletal scintigraphy.

Medical imaging in the diagnosis and management of cancer pain

Within the past few decades medical imaging has evolved very rapidly, now becoming an indispensable tool for the diagnosis, treatment, and follow-up of patients with cancer-related pain. Multiple imaging modalities are available for the assessment of cancer patients, each one with different advantages and limitations that are important to consider at the time we order a diagnostic study or plan an image-guided procedure. This article reviews the role that various imaging modalities play in the management of cancer pain and provides an overview of the latest technological advances.

Whole-body MRI using a sliding table and repositioning surface coil approach

Objective

To introduce and assess a new way of performing whole-body magnetic resonance imaging (MRI) using a non-integrated surface coil approach as available on most clinical MRI systems worldwide.

Methods

Ten consecutive asymptomatic subjects prospectively underwent whole-body MRI for health screening. Whole-body MRI included T1-, T2- and diffusion-weighted sequences, and was performed using a non-integrated surface coil to image four different stations without patient repositioning. The four separately acquired stations were merged, creating seamless coronal whole-body T1-, T2- and diffusion-weighted images. Anatomical alignment, image quality at the boundaries of adjacent stations, and overall image quality of all stations were qualitatively assessed.

Results

The average time (±SD) taken to change the surface coil from one station to the next station was 53.8 (±7.1) s. The average total extra examination time ± SD was 2 min 41.4 s (±15.3 s). Anatomical alignment, image quality at the boundaries of adjacent stations, and overall image quality of all stations of T1-, T2- and diffusion-weighted whole-body MRI were overall graded as “good” to “excellent”.

Conclusion

This study shows that a time-efficient and high-quality whole-body MRI examination can easily be performed by using a non-integrated sliding surface coil approach.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-009-1674-1) contains supplementary material, which is available to authorized users.

[Whole-body diffusion-weighted magnetic resonance imaging in oncology]

Because of its excellent diagnostic performance, whole-body MRI will probably become an alternative to or replacement for positron emission tomography and computed tomography (PET-CT). The sensitivity of diffusion sequences is high. Whole body MRI is used increasingly often in oncology, for initial or follow-up staging, finding primary tumors after identifying metastases, staging for pregnant woman and children, and therapeutic follow-up. Advantages of whole-body MRI over PET-CT include the absence of irradiation as well as the greater availability, and lower cost of MRI.

Detection of bone metastases in non-small cell lung cancer patients: comparison of whole-body diffusion-weighted imaging (DWI), whole-body MR imaging without and with DWI, whole-body FDG-PET/CT, and bone scintigraphy

PURPOSE

To prospectively compare the capability for bone metastasis assessment of whole-body diffusion-weighted imaging (DWI), magnetic resonance imaging (MRI) without and with DWI, [(18)F] fluoro-2-D-glucose positron emission tomography with computed tomography (FDG-PET/CT) and bone scintigraphy in non-small cell carcinoma (NSCLC) patients.

MATERIALS AND METHODS

In all, 115 consecutive NSCLC patients (66 men, 49 women; mean age 72 years) prospectively underwent whole-body MRI, PET/CT, and bone scintigraphy before treatment. For each method, probability of metastasis was independently assessed by using a 5-point visual scoring system on a per-site basis. Receiver operating characteristic (ROC)-based positive tests were used to determine the practical threshold value for each method on a per-site basis. Sensitivities, specificities, and accuracies were then compared on a per-site and per-patient basis by means of McNemar's test.

RESULTS

When the practical threshold values were adapted, specificity and accuracy of whole-body MRI with DWI were significantly higher than those of bone scintigraphy and PET/CT (P < 0.05). On a per-patient basis, specificity and accuracy of whole-body MRI with DWI were significantly higher than those of bone scintigraphy (P < 0.05).

CONCLUSION

Whole-body MRI with DWI can be used for bone metastasis assessment of NSCLC patients as accurate as bone scintigraphy and/or PET/CT.

Advances in imaging in the work-up of head and neck cancer patients

Accurate staging at the time of the diagnosis of head and neck squamous cell carcinoma (HNSCC) is critical for selection of the appropriate treatment strategy. Therefore, optimizing pre-treatment imaging in the diagnostic work-up is of great importance. CT and MRI are the corner stones of diagnostic work-up. Technical improvements will increase the value of these techniques even further. PET and PET-CT became a standard imaging techniques for HNSCC patients. It may be helpful for the detection of occult primary tumours, but its sensitivity for the detection of occult lymph node metastases is too low. Alternatively, the sentinel node procedure may be sufficiently accurate to avoid elective treatment of the neck. Screening for distant metastases should be performed only in HNSCC patients with high risk factors by FDG-PET-CT.

Diffusion-weighted imaging with apparent diffusion coefficient mapping and spectroscopy in prostate cancer

Prostate cancer is a major health problem, and the exploration of noninvasive imaging methods that have the potential to improve specificity while maintaining high sensitivity is still critically needed. Tissue changes induced by tumor growth can be visualized by magnetic resonance imaging (MRI) methods. Current MRI methods include conventional T2-weighted imaging, diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping and magnetic resonance spectroscopy (MRS). Techniques such as DWI/ADC provide functional information about the behavior of water molecules in tissue; MRS can provide biochemical information about the presence or absence of certain metabolites, such as choline, creatine, and citrate. Finally, vascular parameters can be investigated using dynamic contrast-enhanced MRI. Moreover, with whole-body MRI and DWI, metastatic disease can be evaluated in 1 session and may provide a way to monitor treatment. Therefore, when combining these various methods, a multiparametric data set can be built to assist in the detection, localization, assessment of prostate cancer aggressiveness, and tumor staging. Such a comprehensive approach offers more power to evaluate prostate disease than any single measure alone. In this article, we focus on the role of DWI/ADC and MRS in the detection and characterization using both in vivo and ex vivo imaging of prostate pathology.

PET, CT, and MR Imaging for Assessment of Thoracic Malignancy: Structure Meets Function

Imaging of patients with thoracic malignancy usually requires a multimodality approach. Each of these modalities has its own strengths and weaknesses. CT remains central to the staging and restaging of thoracic malignancies, but has recently been complemented with [18F]-2-fluoro-2-deoxy-D-glucose(FDG)-positron emission tomography (PET) imaging to maximize its potential. Furthermore, because FDG-PET/CT is useful at all stages of the workup and treatment of these patients, this modality has taken hold in the clinical realm for evaluation of patients with thoracic malignancy and is rapidly replacing PET-only imaging. MR imaging is also occasionally used in some patients with thoracic malignancies to improve disease staging or lesion characterization. PET/MR imaging may come to be used to evaluate patients with thoracic malignancies as well.

Imaging bone metastases in breast cancer: techniques and recommendations for diagnosis

Bone is the most common site of distant metastases from breast carcinoma. The presence of bone metastases affects a patient's prognosis, quality of life, and the planning of their treatment. We discuss recent innovations in bone imaging and present algorithms, based on the strengths and weaknesses of each technique, to facilitate the most successful and cost-effective choice of imaging studies for the detection of osseous metastases. Skeletal scintigraphy (bone scan) is very sensitive in the detection of osseous metastases and is recommended as the first imaging study in patients who are asymptomatic. Radiographs are recommended for the assessment of abnormal radionuclide uptake or the risk of pathological fracture and as initial imaging studies in patients with bone pain. MRI or PET-CT can be considered for cases of abnormal radionuclide uptake that are not addressed by radiography. Osseous metastases can lead to emergent situations, such as spinal-cord compression or impending fracture of a weight-bearing bone, and imaging guidelines are essential for early detection and initiation of appropriate therapy. The imaging method used in non-emergent situations, such as assessment of the ribs, sternum, pelvis, hips, and joints, should be guided by the strengths and limitations of each technique.

Fast dixon-based multisequence and multiplanar MRI for whole-body detection of cancer metastases

PURPOSE

To develop and demonstrate the feasibility of multisequence and multiplanar MRI for whole-body cancer detection.

MATERIALS AND METHODS

Two fast Dixon-based sequences and a diffusion-weighted sequence were used on a commercially available 1.5 T scanner for whole-body cancer detection. The study enrolled 19 breast cancer patients with known metastases and in multistations acquired whole-body axial diffusion-weighted, coronal T2-weighted, axial/sagittal pre- and postcontrast T1-weighted, as well as triphasic abdomen images. Three radiologists subjectively scored Dixon images of each series for overall image quality and fat suppression uniformity on a 4-point scale (1 = poor, 2 = fair, 3 = good, and 4 = excellent).

RESULTS

Eighteen of the 19 patients completed the whole-body MRI successfully. The mean acquisition time and overall patient table time were 46 +/- 3 and 69 +/- 5 minutes, respectively. The average radiologists' scores for overall image quality and fat suppression uniformity were both 3.4 +/- 0.5. The image quality was consistent between patients and all completed whole-body examinations were diagnostically adequate.

CONCLUSION

Whole-body MRI offering essentially all the most optimal tumor-imaging sequences in a typical 1-hour time slot can potentially become an appealing "one-stop-shop" for whole-body cancer imaging.

Whole-body diffusion-weighted magnetic resonance imaging

Diffusion-weighted magnetic resonance imaging (DWI) provides information on the diffusivity of water molecules in the human body. Technological advances and the development of the concept of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) have opened the path for routine clinical whole-body DWI. Whole-body DWI allows detection and characterization of both oncological and non-oncological lesions throughout the entire body. This article reviews the basic principles of DWI and the development of whole-body DWI, illustrates its potential clinical applications, and discusses its limitations and challenges.