Thomas C. Kwee

Imaging in Local Staging of Gastric Cancer: A Systematic Review

PURPOSEnEndoscopic ultrasound (EUS) has been established as the diagnostic modality of choice in local (T) staging of gastric cancer. Multidetector row computed tomography (MDCT) and magnetic resonance imaging (MRI) are promising alternatives. The aim of this study was to systematically review the literature regarding the performance of each of these imaging modalities.nnnMETHODSnA systematic search for relevant studies was performed in the PubMed/MEDLINE and EMBASE databases. Two reviewers independently assessed the methodological quality of each study. Local staging performance of included studies was calculated.nnnRESULTSnTwenty-two EUS studies, five MDCT studies, one combined EUS and MDCT study, and three MRI studies met the inclusion criteria. The studies were of moderate methodological quality. Diagnostic accuracy of overall T staging for EUS, MDCT, and MRI varied between 65% to 92.1%, 77.1% to 88.9%, and 71.4% to 82.6%, respectively. Sensitivity for assessing serosal involvement for EUS, MDCT, and MRI varied between 77.8% to 100%, 82.8% to 100%, and 89.5% to 93.1%, respectively. Specificity for assessing serosal involvement for EUS, MDCT, and MRI varied between 67.9% to 100%, 80% to 96.8%, and 91.4% to 100%, respectively.nnnCONCLUSIONnEUS, MDCT, and MRI achieve similar results in terms of diagnostic accuracy in T staging and in assessing serosal involvement. Most experience has been gained with EUS. Few MDCT studies and even fewer MRI studies are available. Thus, EUS remains the first-choice imaging modality in preoperative T staging of gastric cancer.

Whole-body MRI, including diffusion-weighted imaging, for the initial staging of malignant lymphoma: comparison to computed tomography.

Purpose:To assess the value of whole-body magnetic resonance imaging (MRI), including diffusion-weighted imaging (DWI), for the initial staging of malignant lymphoma, compared with computed tomography (CT). Materials and Methods:Thirty-one consecutive patients with newly diagnosed malignant lymphoma prospectively underwent whole-body MRI (T1-weighted and short inversion time inversion recovery [n = 31], and DWI [n = 28]) and CT. Ann Arbor stages were assigned by 1 radiologist according to whole-body MRI findings, and by another radiologist according to CT findings. Differences in staging between whole-body MRI (without and with DWI) and CT were resolved using other (imaging) studies (including 18F-fluoro-2-deoxyglucose positron emission tomography and bone marrow biopsy) and follow-up studies as reference standard. Results:Staging results of whole-body MRI without DWI were equal to those of CT in 74% (23/31), higher in 26% (8/31), and lower in 0% (0/31) of patients, with correct/incorrect/unresolved overstaging relative to CT in 3, 2, and 2 patients, respectively, and incorrect staging of both modalities in 1 patient. Staging results of whole-body MRI with DWI were equal to those of CT in 75% (21/28), higher in 25% (7/28), and lower in 0% (0/28) of patients, with correct/incorrect overstaging relative to CT in 6 and 1 patient(s), respectively. Conclusion:Our results suggest that initial staging of malignant lymphoma using whole-body MRI (without DWI and with DWI) equals staging using CT in the majority of patients, whereas whole-body MRI never understaged relative to CT. Furthermore, whole-body MRI mostly correctly overstaged relative to CT, with a possible advantage of using DWI.

Whole-Body Diffusion-Weighted MRI: Tips, Tricks, and Pitfalls

OBJECTIVEnWe examine the clinical impetus for whole-body diffusion-weighted MRI and discuss how to implement the technique with clinical MRI systems. We include practical tips and tricks to optimize image quality and reduce artifacts. The interpretative pitfalls are enumerated, and potential challenges are highlighted.nnnCONCLUSIONnWhole-body diffusion-weighted MRI can be used for tumor staging and assessment of treatment response. Meticulous technique and knowledge of potential interpretive pitfalls will help to avoid mistakes and establish this modality in radiologic practice.

Diffusion-weighted MR Neurography of the Brachial Plexus: Feasibility Study

The University Medical Center Utrecht institutional review board approved this study, and informed consent was obtained from all subjects. The purpose of this study was to introduce and assess diffusion-weighted (DW) magnetic resonance (MR) neurography for imaging of the brachial plexus. DW MR neurographic images were displayed with a maximum intensity projection technique. DW MR neurography was evaluated in five healthy volunteers and five patients. DW MR neurography showed a long trajectory of the brachial plexus in all healthy volunteers. In all patients, DW MR neurography clearly showed the location of the disease. The proposed DW MR neurography technique can be used to obtain an overview image of the brachial plexus, with excellent conspicuity of the nerves and surrounding structures.

Whole-Body Magnetic Resonance Neurography

This report describes an MR-based approach that is capable of selectively visualizing the peripheral nervous system over long trajectories in a single examination: whole-body MR neurography.

FDG PET for diagnosing infection in hip and knee prostheses: prospective study in 221 prostheses and subgroup comparison with combined (111)In-labeled leukocyte/(99m)Tc-sulfur colloid bone marrow imaging in 88 prostheses.

Purpose This study aims to assess and compare the value of FDG PET with combined 111In-labeled leukocyte/99mTc-sulfur colloid bone marrow (WBC/BM) imaging for diagnosing infection in hip and knee prostheses. Methods In this prospective study, patients with painful hip or knee arthroplasty, who were scheduled to undergo clinical and diagnostic evaluation for prosthesis revision, were included. They have been studied by using FDG PET and WBC/BM scan. This study was institutional review board approved and Health Insurance Portability and Accountability Act compliant. All patients provided written informed consent. Results A total of 134 hip and 87 knee prostheses, suspected of being either infected or noninfectious loosening, were evaluated. All 221 prostheses underwent FDG PET, whereas both WBC/BM imaging and FDG PET were performed in 88 prostheses. The initial analysis of data from the WBC/BM images demonstrated somewhat suboptimal results compared with those of FDG PET scans on 88 patients. In addition, some patients were not willing to undergo both procedures and therefore participate in this study. Therefore, a decision was made to eliminate WBC/BM imaging from the procedures for the remainder of this research study. This decision was reached partly because of the significant radiation dose delivered from labeled WBC and safety issues related to preparing these labeled cells. Final diagnosis was based on microbiological examinations of the surgical specimens in 125 prostheses and joint aspirations combined with the clinical follow-up of 6 months or more in 86 prostheses. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG PET in hip prostheses were 81.8%, 93.1%, 79.4%, and 94.0%, respectively, and in knee prostheses were 94.7%, 88.2%, 69.2%, and 98.4%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of WBC/BM imaging in hip prostheses were 38.5%, 95.7%, 71.4%, and 84.6%, respectively, and in knee prostheses were 33.3%, 88.5%, 25.0%, and 92.0%, respectively. In those cases that underwent both FDG PET and WBC/BM imaging, there was a trend (P = 0.0625) toward a higher sensitivity for FDG PET in hip prostheses, whereas other comparisons did not show any significant differences between the 2 imaging modalities. Conclusions Based on this study, the diagnostic performance of FDG PET scan in detecting infection in painful hip and knee prostheses is optimal for routine clinical application. Considering the complexity and costs of WBC/BM imaging and related safety issues associated with this preparation, FDG PET seems to be an appropriate alternative for assessing these patients.

Diffusion-weighted MR neurography of the sacral plexus with unidirectional motion probing gradients

BackgroundThis technical note introduces diffusion-weighted (DW) MR neurography (MRN) of the sacral plexus with unidirectional motion probing gradients (MPGs).MethodsThis is compared with DW MRN with three-directional and six-directional MPGs.Results and conclusionThis paper indicates that DW MRN of the sacral plexus should be performed with unidirectional MPGs.

Prognostic value of complete remission status at end‐of‐treatment FDG‐PET in R‐CHOP‐treated diffuse large B‐cell lymphoma: systematic review and meta‐analysis

This study systematically reviewed and meta‐analysed the prognostic value of complete remission status at end‐of‐treatment 18F‐fluoro‐2‐deoxy‐d‐glucose positron emission tomography (FDG‐PET) in diffuse large B‐cell lymphoma (DLBCL) patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R‐CHOP). The systematic PubMed/MEDLINE search yielded seven suitable studies comprising a total of 737 R‐CHOP‐treated DLBCL patients who were in complete remission at end‐of‐treatment FDG‐PET. Overall, the methodological quality of included studies was reasonable. The disease relapse rate among all patients with complete remission status according to end‐of‐treatment FDG‐PET ranged from 7·0% to 20·0%, with a weighted summary proportion of 13·7%. Five of seven studies reported progression‐free survival (PFS) of these patients at various specific time points, i.e., 2‐year PFS (n = 1), estimated 3‐year PFS (n = 3) and 5‐year PFS (n = 1), which was 83%, 85–86·4% and 75%, respectively. Three of seven studies reported overall survival (OS) of these patients at various specific time points, i.e., estimated 3‐year OS (n = 2) and estimated 5‐year OS (n = 1), which were 90%, 93·6% and 83%, respectively. In conclusion, a non‐negligible proportion of R‐CHOP‐treated DLBCL patients who achieve complete remission according to end‐of‐treatment FDG‐PET experiences disease relapse during follow‐up.

Magnetic resonance imaging for the detection of bone marrow involvement in malignant lymphoma

This study systematically reviewed the published data regarding the sensitivity of magnetic resonance imaging (MRI) compared with bone marrow biopsy as reference standard for the detection of bone marrow involvement in patients with malignant lymphoma. A systematic search for relevant studies was performed of the PubMed/MEDLINE and Embase databases. Two reviewers independently assessed the methodological quality of each study and the sensitivity of the included studies was calculated. The 11 included studies had moderate methodological quality. Sensitivity of MRI for the detection of bone marrow involvement ranged from 50% to 100%, with a median of 100%. MRI is probably sufficiently sensitive to rule out bone marrow involvement in patients with malignant lymphoma. However, a well‐designed study with a large sample size is needed to confirm current results.

Assessment of Small Bowel Motility in Patients With Chronic Intestinal Pseudo-Obstruction Using Cine-MRI

OBJECTIVES:Chronic intestinal pseudo-obstruction (CIPO) is a rare, serious motility disorder, with life-threatening complications over time. However, lack of an established, non-invasive diagnostic method has caused delays in the diagnosis of this intractable disease. Cine-magnetic resonance imaging (MRI) is an emerging technique, with a potential to evaluate the motility of the entire bowel. We compared small bowel motility in healthy volunteers, patients with irritable bowel syndrome (IBS), and those with CIPO, using cine-MRI, and evaluated the usefulness of cine-MRI as a novel diagnostic method for CIPO.METHODS:Twelve healthy volunteers, IBS patients, and CIPO patients prospectively underwent cine-MRI at 1.5u2009T. Luminal diameter, contraction ratio, and contraction cycle were measured and compared between the groups.RESULTS:Cine-MRI provided sufficient dynamic images to assess the motility of the entire small bowel. Luminal diameter (mean±s.d.) in CIPO patients was significantly higher than that in healthy volunteers and IBS patients (43.4±14.1, 11.1±1.5, and 10.9±1.9u2009mm, respectively), and contraction ratio was significantly lower in CIPO patients than that in healthy volunteers and IBS patients (17.1±11.0%, 73.0±9.3%, and 74.6±9.4%, respectively). No significant differences were observed in the contraction cycle.CONCLUSIONS:This study is the first to assess the clinical utility of cine-MRI in CIPO patients. Cine-MRI clearly detected contractility impairments in CIPO patients. Cine-MRI is noninvasive, radiation-free, and can directly evaluate the entire small bowel peristalsis, and can detect the affected loops at a glance; therefore, it might be extremely useful for the diagnosis and follow-up of CIPO patients in clinical practice.