Frank J. Wessels

The peri‐esophageal connective tissue layers and related compartments: visualization by histology and magnetic resonance imaging

An organized layer of connective tissue coursing from aorta to esophagus was recently discovered in the mediastinum. The relations with other peri‐esophageal fascias have not been described and it is unclear whether this layer can be visualized by non‐invasive imaging. This study aimed to provide a comprehensive description of the peri‐esophageal fascias and determine whether the connective tissue layer between aorta and esophagus can be visualized by magnetic resonance imaging (MRI). First, T2‐weighted MRI scanning of the thoracic region of a human cadaver was performed, followed by histological examination of transverse sections of the peri‐esophageal tissue between the thyroid gland and the diaphragm. Secondly, pretreatment motion‐triggered MRI scans were prospectively obtained from 34 patients with esophageal cancer and independently assessed by two radiologists for the presence and location of the connective tissue layer coursing from aorta to esophagus. A layer of connective tissue coursing from the anterior aspect of the descending aorta to the left lateral aspect of the esophagus, with a thin extension coursing to the right pleural reflection, was visualized ex vivo in the cadaver on MR images, macroscopic tissue sections, and after histologic staining, as well as on in vivo MR images. The layer connecting esophagus and aorta was named ‘aorto‐esophageal ligament’ and the layer connecting aorta to the right pleural reflection ‘aorto‐pleural ligament’. These connective tissue layers divides the posterior mediastinum in an anterior compartment containing the esophagus, (carinal) lymph nodes and vagus nerve, and a posterior compartment, containing the azygos vein, thoracic duct and occasionally lymph nodes. The anterior compartment was named ‘peri‐esophageal compartment’ and the posterior compartment ‘para‐aortic compartment’. The connective tissue layers superior to the aortic arch and at the diaphragm corresponded with the currently available anatomic descriptions. This study confirms the existence of the previously described connective tissue layer coursing from aorta to esophagus, challenging the long‐standing paradigm that no such structure exists. A comprehensive, detailed description of the peri‐esophageal fascias is provided and, furthermore, it is shown that the connective tissue layer coursing from aorta to esophagus can be visualized in vivo by MRI.

Efficacy of radioembolization with holmium-166 microspheres in salvage patients with liver metastases: a phase 2 study.

Radioembolization of liver malignancies with 166Ho-microspheres has been shown to be safe in a phase 1 dose-escalation study. The purpose of this study was to investigate the efficacy of 166Ho radioembolization. Methods: In this prospective single-arm study, 56 patients were enrolled, all with liver metastases refractory to systemic therapy and ineligible for surgical resection. The primary outcome was a response by 2 target lesions on triphasic liver CT scans 3 mo after therapy, as assessed using RECIST, version 1.1. Secondary outcomes included overall tumor response, time to imaging progression, overall survival, toxicity, quality of life, and quantification of the microspheres on SPECT and MRI. Results: Between May 2012 and March 2015, 38 eligible patients were treated, one of whom was not evaluable. In 27 (73%) of 37 patients, the target lesions showed complete response, partial response, or stable disease (disease control) at 3 mo (95% confidence interval [CI], 57%–85%). The median overall survival was 14.5 mo (95% CI, 8.6–22.8 mo). For colorectal cancer patients (n = 23), the median overall survival was 13.4 mo (95% CI, 8.2–15.7 mo). Grade 3 or 4 toxic events after treatment (according to the Common Terminology Criteria for Adverse Events, version 4.03) included abdominal pain (in 18% of patients), nausea (8%), ascites (3%), fatigue (3%), gastric stenosis (3%), hepatic failure (3%), liver abscesses (3%), paroxysmal atrial tachycardia (3%), thoracic pain (3%), upper gastrointestinal hemorrhage (3%), and vomiting (3%). On SPECT, 166Ho could be quantified with high accuracy and precision, with a mean overestimation of 9.3% ± 7.1% in the liver. Conclusion: Radioembolization with 166Ho-microspheres induced a tumor response with an acceptable toxicity profile in salvage patients with liver metastases.

Radiological Workup of Cystic Neoplasms of the Pancreas

Pancreatic cystic lesions are being detected with increasing frequency because of increased use and improved quality of cross-sectional imaging techniques. Pancreatic cystic lesions encompass non-neoplastic lesions (such as pancreatitis-related collections) and neoplastic tumors. Common cystic pancreatic neoplasms include serous cystadenomas, mucinous cystic neoplasms, intraductal papillary mucinous neoplasms, and solid pseudopapillary tumors. These cystic pancreatic neoplasms may have typical morphology, but at times show overlapping imaging features on cross-sectional examinations. This article reviews the classical and atypical imaging features of commonly encountered cystic pancreatic neoplasms and presents the limitations of current cross-sectional imaging techniques in accurately classifying pancreatic cystic lesions.

Radiation dose reduction for CT assessment of urolithiasis using iterative reconstruction: A prospective intra-individual study.

ObjectiveTo assess the performance of hybrid (HIR) and model-based iterative reconstruction (MIR) in patients with urolithiasis at reduced-dose computed tomography (CT).MethodsTwenty patients scheduled for unenhanced abdominal CT for follow-up of urolithiasis were prospectively included. Routine dose acquisition was followed by three low-dose acquisitions at 40%, 60% and 80% reduced doses. All images were reconstructed with filtered back projection (FBP), HIR and MIR. Urolithiasis detection rates, gall bladder, appendix and rectosigmoid evaluation and overall subjective image quality were evaluated by two observers.Results74 stones were present in 17 patients. Half the stones were not detected on FBP at the lowest dose level, but this improved with MIR to a sensitivity of 100%. HIR resulted in a slight decrease in sensitivity at the lowest dose to 72%, but outperformed FBP. Evaluation of other structures with HIR at 40% and with MIR at 60% dose reductions was comparable to FBP at routine dose, but 80% dose reduction resulted in non-evaluable images.ConclusionsCT radiation dose for urolithiasis detection can be safely reduced by 40 (HIR)–60 (MIR) % without affecting assessment of urolithiasis, possible extra-urinary tract pathology or overall image quality.Key Points• Iterative reconstruction can be used to substantially lower the radiation dose.• This allows for radiation reduction without affecting sensitivity of stone detection.• Possible extra-urinary tract pathology evaluation is feasible at 40–60% reduced dose.

Evaluation of motion correction for clinical dynamic contrast enhanced MRI of the liver

Motion correction of 4D dynamic contrast enhanced MRI (DCE-MRI) series is required for diagnostic evaluation of liver lesions. The registration, however, is a challenging task, owing to rapid changes in image appearance. In this study, two different registration approaches are compared; a conventional pairwise method applying mutual information as metric and a groupwise method applying a principal component analysis based metric, introduced by Huizinga et al (2016). The pairwise method transforms the individual 3D images one by one to a reference image, whereas the groupwise registration method computes the metric on all the images simultaneously, exploiting the temporal information, and transforms all 3D images to a common space. The performance of the two registration methods was evaluated using 70 clinical 4D DCE-MRI series with the focus on the liver. The evaluation was based on the smoothness of the time intensity curves in lesions, lesion volume change after deformation and the smoothness of spatial deformation. Furthermore, the visual quality of subtraction images (pre-contrast image subtracted from the post contrast images) before and after registration was rated by two observers. Both registration methods improved the alignment of the DCE-MRI images in comparison to the non-corrected series. Furthermore, the groupwise method achieved better temporal alignment with smoother spatial deformations than the pairwise method. The quality of the subtraction images was graded satisfactory in 32% of the cases without registration and in 77% and 80% of the cases after pairwise and groupwise registration, respectively. In conclusion, the groupwise registration method outperforms the pairwise registration method and achieves clinically satisfying results. Registration leads to improved subtraction images.

Diagnostic performance of a CT-based scoring system for diagnosis of anastomotic leakage after esophagectomy: comparison with subjective CT assessment

ObjectiveTo develop a CT-based prediction score for anastomotic leakage after esophagectomy and compare it to subjective CT interpretation.MethodsConsecutive patients who underwent a CT scan for a clinical suspicion of anastomotic leakage after esophagectomy with cervical anastomosis between 2003 and 2014 were analyzed. The CT scans were systematically re-evaluated by two radiologists for the presence of specific CT findings and presence of an anastomotic leak. Also, the original CT interpretations were acquired. These results were compared to patients with and without a clinical confirmed leak.ResultsOut of 122 patients that underwent CT for a clinical suspicion of anastomotic leakage; 54 had a confirmed leak. In multivariable analysis, anastomotic leakage was associated with mediastinal fluid (OR = 3.4), esophagogastric wall discontinuity (OR = 4.9), mediastinal air (OR = 6.6), and a fistula (OR = 7.2). Based on these criteria, a prediction score was developed resulting in an area-under-the-curve (AUC) of 0.86, sensitivity of 80%, and specificity of 84%. The original interpretation and the systematic subjective CT assessment by two radiologists resulted in AUCs of 0.68 and 0.75 with sensitivities of 52% and 69%, and specificities of 84% and 82%, respectively.ConclusionThis CT-based score may provide improved diagnostic performance for diagnosis of anastomotic leakage after esophagectomy.Key Points• A CT-based score provides improved diagnostic performance for diagnosis of anastomotic leakage.• Leakage associations include mediastinal fluid, mediastinal air, wall discontinuity, and fistula.• A scoring system yields superior diagnostic accuracy compared to subjective CT assessment.• Radiologists may suggest presence of anastomotic leakage based on a prediction score.

Cervical ultrasonography has no additional value over negative 18F-FDG PET/CT scans for diagnosing cervical lymph node metastases in patients with oesophageal cancer

AbstractObjectivesTo investigate the additional value of cervical ultrasonography over 18F-FDG PET/CT for diagnosing cervical lymph node metastases in patients with newly diagnosed oesophageal cancer.MethodsBetween January 2013 and January 2016, 163 patients with newly diagnosed oesophageal cancer underwent both cervical ultrasonography and 18F-FDG PET/CT at a tertiary referral centre in the Netherlands. Retrospective clinical data analysis was performed to assess the diagnostic value of cervical ultrasonography and 18F-FDG PET/CT for the detection of cervical lymph node metastases. Fine needle aspiration or clinical follow-up was used as reference standard.ResultsThe overall incidence of patients with cervical lymph node metastases was 14%. The sensitivity of 18F-FDG PET/CT to detect cervical lymph node metastases was 82% (95% CI 59–94%) and specificity was 91% (95% CI 85–95%). The sensitivity and specificity of cervical ultrasonography were 73% (95% CI 50–88%) and 84% (95% CI 77–90%), respectively. In patients with a negative 18F-FDG PET/CT, 12 of 133 (9%) patients had suspicious nodes on cervical ultrasonography. In all these 12 patients the nodes were confirmed benign.ConclusionsCervical ultrasonography has no additional diagnostic value to a negative integrated 18F-FDG PET/CT for the detection of cervical lymph node metastases in patients with newly diagnosed oesophageal cancer.Key Points• Cervical ultrasonography has no value over PET/CT in evaluating cervical node metastases. • PET/CT provides greater diagnostic confidence compared to cervical ultrasonography. • Cervical ultrasonography during standard diagnostic work-up may be considered unnecessary. • Cervical lesions on PET/CT require cytopathological confirmation by FNA.

The diagnostic performance of CT versus FDG PET-CT for the detection of recurrent pancreatic cancer: a systematic review and meta-analysis

OBJECTIVES Radiologic surveillance after resection of pancreatic ductal adenocarcinoma (PDAC) can provide information on the extent and location of disease recurrence. This systematic review and meta-analysis aims to give an overview of the literature on the diagnostic performance of different imaging modalities for the detection of recurrent disease after surgery for PDAC. METHODS A systematic search was performed in PubMed, EMBASE and Cochrane Library up to 20 December 2017. All studies reporting on the diagnostic value of imaging modalities for the detection of local and/or distant disease recurrence during follow-up after resection of PDAC were eligible. Both histologic confirmation of recurrent PDAC and clinical confirmation by disease progression on follow-up imaging were considered as suitable reference standard. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used for critical appraisal of methodological quality. Diagnostic accuracy data were extracted or calculated and presented in forest plots. A bivariate random-effects model was used to calculate pooled estimates of sensitivity and specificity. RESULTS A total of seven retrospective studies with 333 relevant patients were ultimately eligible for data extraction. Overall, the methodological quality of the included studies was acceptable. All seven articles described test results of contrast-enhanced CT, whilst five and three articles reported outcomes on diagnostic accuracy of FDG PET-CT and FDG PET-CT combined with contrast-enhanced CT, respectively. For CT, pooled estimates for sensitivity were 0.70 (95% CI 0.61-0.78) and for specificity 0.80 (95% CI 0.69-0.88). For FDG PET-CT, pooled estimates for sensitivity and specificity were 0.88 (95% CI 0.81-0.93) and 0.89 (95% CI 0.80-0.94), respectively. For FDG PET-CT in combination with contrast-enhanced CT, pooled estimates for sensitivity were 0.95 (95% CI 0.88-0.98) and for specificity 0.81 (95% CI 0.63-0.92). CONCLUSIONS According to the current literature, post-operative CT has a moderate diagnostic accuracy in the detection of recurrent disease. FDG PET-CT imaging could be of additional value when disease recurrence is suspected despite negative or equivocal CT findings. Nevertheless, evidence supporting radiologic surveillance after resection of PDAC is limited. Future prospective studies are needed to optimize surveillance strategies after resection of pancreatic cancer.

Improving early diagnosis of pulmonary infections in patients with febrile neutropenia using low-dose chest computed tomography

We performed a prospective study in patients with chemotherapy induced febrile neutropenia to investigate the diagnostic value of low-dose computed tomography compared to standard chest radiography. The aim was to compare both modalities for detection of pulmonary infections and to explore performance of low-dose computed tomography for early detection of invasive fungal disease. The low-dose computed tomography remained blinded during the study. A consensus diagnosis of the fever episode made by an expert panel was used as reference standard. We included 67 consecutive patients on the first day of febrile neutropenia. According to the consensus diagnosis 11 patients (16.4%) had pulmonary infections. Sensitivity, specificity, positive predictive value and negative predictive value were 36%, 93%, 50% and 88% for radiography, and 73%, 91%, 62% and 94% for low-dose computed tomography, respectively. An uncorrected McNemar showed no statistical difference (p = 0.197). Mean radiation dose for low-dose computed tomography was 0.24 mSv. Four out of 5 included patients diagnosed with invasive fungal disease had radiographic abnormalities suspect for invasive fungal disease on the low-dose computed tomography scan made on day 1 of fever, compared to none of the chest radiographs. We conclude that chest radiography has little value in the initial assessment of febrile neutropenia on day 1 for detection of pulmonary abnormalities. Low-dose computed tomography improves detection of pulmonary infiltrates and seems capable of detecting invasive fungal disease at a very early stage with a low radiation dose.