Claus Jensen

Detection of Pulmonary Embolism with Combined Ventilation–Perfusion SPECT and Low-Dose CT: Head-to-Head Comparison with Multidetector CT Angiography

The diagnosis of pulmonary embolism (PE) is usually established by a combination of clinical assessment, D-dimer testing, and imaging with either pulmonary ventilation–perfusion (V/Q) scintigraphy or pulmonary multidetector CT (MDCT) angiography. Both V/Q SPECT and MDCT angiography seem to have high diagnostic accuracy. However, only limited data directly comparing these 2 modalities are available. Hybrid γ-camera/MDCT systems have been introduced and allow simultaneous 3-dimensional lung V/Q SPECT and MDCT angiography, suitable for diagnosing PE. The aim of our study was to compare, in a prospective design, the diagnostic ability of V/Q SPECT, V/Q SPECT combined with low-dose CT, and pulmonary MDCT angiography obtained simultaneously using a combined SPECT/MDCT scanner in patients suspected of having PE. Methods: Consecutive patients from June 2006 to February 2008 suspected of having acute PE were referred to the Department of Nuclear Medicine at Rigshospitalet or Frederiksberg Hospital, Denmark, for V/Q SPECT as a first-line imaging procedure. The number of eligible patients was 196. Patients with positive D-dimer results (>0.5 mmol/mL) or a clinical assessment with a Wells score greater than 2 were included and underwent V/Q SPECT, low-dose CT, and pulmonary MDCT angiography in a single session. Patient follow-up was 6 mo. Results: A total of 81 simultaneous studies were available for analysis, of which 38% were from patients with PE. V/Q SPECT had a sensitivity of 97% and a specificity of 88%. When low-dose CT was added, the sensitivity was still 97% and the specificity increased to 100%. Perfusion SPECT with low-dose CT had a sensitivity of 93% and a specificity of 51%. MDCT angiography alone had a sensitivity of 68% and a specificity of 100%. Conclusion: We conclude that V/Q SPECT in combination with low-dose CT without contrast enhancement has an excellent diagnostic performance and should therefore probably be considered first-line imaging in the work-up of PE in most cases.

Comparison of V/Q SPECT and planar V/Q lung scintigraphy in diagnosing acute pulmonary embolism.

PurposePlanar ventilation/perfusion (V/Q) scintigraphy is currently the standard method for the diagnosis of pulmonary embolism (PE) in most nuclear medicine centers. However, recent studies have shown a superior sensitivity and specificity when applying V/Q single photon emission computed tomography (SPECT) in diagnosing PE. This study evaluated the diagnostic performance of three-dimensional V/Q SPECT in comparison with planar V/Q scintigraphy. Materials and methodsConsecutive patients suspected of acute PE from June 2006 to February 2008 were referred to the Department of Nuclear Medicine at Frederiksberg Hospital, Denmark to a V/Q SPECT, as the first-line imaging procedure. Patients with positive D-dimer (>0.5 mg/l) or after clinical assessment with a Wells score of more than 2 were included and had a V/Q SPECT, low-dose CT, planar V/Q scintigraphy, and pulmonary multidetector computer tomography angiography performed the same day. Ventilation studies were performed using 81mKr. Patient follow-up was at least 6 months. ResultsA total of 36 patient studies were available for analysis, of which 11 (31%) had PE. V/Q SPECT had a sensitivity of 100% and a specificity of 87%. Planar V/Q scintigraphy had a sensitivity of 64% and a specificity of 72%. ConclusionWe conclude that V/Q SPECT has a superior diagnostic performance compared with planar V/Q scintigraphy and should be preferred when diagnosing PE.

Chromogranin A is a sensitive marker of progression or regression in ileo-cecal neuroendocrine tumors

Abstract Objective. The correlation between plasma Chromogranin A concentrations and changes in tumor size evaluated by computed tomography (CT) – as a gold standard - was evaluated. Material and methods. One hundred and sixteen patients with CgA-producing ileo-cecal neuroendocrine tumors were evaluated by events, which were recorded when a CT was followed by another CT 1 - 12 months later. Change in tumor size was defined as regression, progression, or stable disease using RECIST criteria 1.1. Of 426 events, there were 97 with progression, 279 with stable disease, and 50 with regression. Based on the ROC curves a cutoff value of 25% change was selected to discriminate between increased, decreased, or unchanged CgA concentrations in plasma, using a sensitive radioimmunoassay with well-defined epitope specificity. Results. In the 97 events showing tumor progression diagnostic sensitivity and specificity of an increased CgA concentration were 86% and 86%, respectively. The positive and negative predictive values were 64% and 85%, respectively. In the 279 events with unchanged tumor size the diagnostic sensitivity and specificity of an unchanged CgA concentration were 73% and 86%, and the positive and negative predictive values were 91% and 63%, respectively. In the 50 events showing tumor regression, diagnostic sensitivity and specificity of a decrease in CgA concentration were 78% and 91%, the positive and negative predictive values being 55% and 97%. Conclusions. CgA concentrations in plasma have a high diagnostic accuracy in monitoring patients with ileo-cecal neuroendocrine tumors. In particular, an increase in plasma CgA concentration was useful to indicate tumor progression.

Use of prophylactic voriconazole for three months after lung transplantation does not reduce infection with Aspergillus: a retrospective study of 147 patients

Background: This was a retrospective study analyzing the mortality and incidence of Aspergillus infection and invasive disease, comparing patients given voriconazole for 3 months following transplantation to patients not given prophylaxis. Methods: All consecutive patients (n = 147) transplanted at Copenhagen University Hospital, Rigshospitalet from 2002 to 2006 were included in the study; the study period included the 2 years before the initiation of fungal prophylaxis (88 patients) and the 2 years after (59 patients). Eight patients transplanted in this period were excluded leaving 139 patients in the study. Results: No effect of voriconazole on the incidence of Aspergillus infection (colonization, or superficial or invasive infection) or on the time from transplantation to the first sign of infection was seen when the 2 groups of patients were compared. The cumulated incidence of infection was 45% without and 49% with prophylaxis, and in both groups approximately half of the infections occurred in the first 3 months, the time during which prophylaxis was given. There were significantly more cystic fibrosis (CF) patients among the Aspergillus-infected patients compared to other diagnoses, and the effect of prophylaxis was the same as in non-CF patients. There was a significantly lower mortality in the voriconazole-treated group compared to the non-prophylaxis group, but in an isolated analysis of Aspergillus-infected patients this difference no longer existed; hence, the difference in mortality must be attributable to a time effect and not to voriconazole prophylaxis. Conclusions: Routine use of voriconazole treatment for prophylaxis against Aspergillus infection in lung transplant recipients does not appear to be warranted.

Usefulness of contrast-enhanced transabdominal ultrasound for tumor classification and tumor staging in the pancreatic head.

Abstract Objective. To evaluate contrast-enhanced ultrasound (CEUS) and compare it to ultrasound (US) and 64-slice-CT (64-CT) for diagnosing, staging and evaluation of resectability of pancreatic cancer. Material and methods. US, CEUS and 64-CT were performed in 49 consecutive patients with pancreatic head tumors and with suspected cancer. After evaluation 44 patients had pancreatic head adenocarcinoma and 5 had chronic pancreatitis, all confirmed by histology. Results. The sensitivity of US, CEUS and 64-CT for diagnosing malignant pancreatic head tumors was 89%, 86% and 93%, respectively, and the overall accuracy was 82%, 86% and 88% respectively. There was no significant difference in the malignant tumor size measurement between US and CEUS (p = 0.3619) or between US and 64-CT (p = 0.2129), but a significant difference was seen in the size measured by CEUS and 64-CT (p = 0.0197). The CEUS measurements on the tumor size were smaller. The overall accuracy for M staging of the patients who had surgery for adenocarcinoma was 86% and 90% for US + CEUS and 64-CT, respectively. By performing the CEUS and 64-CT we additionally found, respectively, 35% and 45% non-resectable patients of a group of patients, who were considered resectable on the primary radiological image material. Conclusions. CEUS may be a useful diagnostic tool in the diagnosis and staging of pancreatic head tumors. For the assessment of resectability CEUS did not prove useful. However, CEUS seemed very useful as an additional instrument in the detection of non-resectable patients already considered resectable on primary radiological image material.

ANP, BNP and D-dimer predict right ventricular dysfunction in patients with acute pulmonary embolism

Background:  The aim of this study was to predict right ventricular dysfunction (RVD) using plasma concentration of D‐dimer, pro‐atrial natriuretic peptide (pro‐ANP), brain natriuretic peptide (BNP), endothelin‐1 (ET‐1) and cardiac troponin I (TNI) in patients with pulmonary embolism (PE).

Added value of combined simultaneous lung ventilation-perfusion single-photon emission computed tomography/multi-slice-computed tomography angiography in two patients suspected of having acute pulmonary embolism.

Pulmonary embolism is diagnosed by a combination of clinical assessment, D-dimer test and imaging with either pulmonary scintigraphy or computed tomography (CT) angiography (1). Both imaging methods have their pros and cons, and none can diagnose all cases. However, both modalities have been improved recently. CT angiography is now performed as multislice CT (MSCT). Lung scintigraphy can be performed as three-dimensional (3-D) scintigraphy, singlephoton emission computed tomography (SPECT) (2). In fact, hybrid gamma camera/MSCT systems have been introduced, which allow simultaneous 3-D lung SPECT and CT angiography, which may be used to diagnose pulmonary embolism (3). We report two cases where combined lung ventilation–perfusion (V/Q) SPECT/MSCT angiography was used in patients suspected of acute pulmonary embolism.

Primary graft dysfunction; possible evaluation by high resolution computed tomography, and suggestions for a scoring system

We have reviewed and discussed current knowledge on existing scoring systems regarding high resolution computed tomography (HRCT) images for the assessment of primary graft dysfunction (PGD) after lung transplantation. Adult respiratory distress syndrome (ARDS) has been more widely studied and appears to have many morphological features similar to what is found in PGD, and might, therefore, be usefully extrapolated to PGD. Principles of HRCT, scoring systems based on HRCT and various terms describing PGD were reviewed and summarized. The sensitivity, inter-intra observer variability, and reproducibility of these systems were discussed. Lastly, the future perspectives for 64-multi-slice computed tomography (MSCT) in relation to PGD were discussed. Few studies on scoring systems of lung tissue by HRCT in ARDS patients and idiopathic pulmonary fibrosis (IPF) patients were found. Most studies were performed on patients with cystic fibrosis (CF). Sensitivity of HRCT for the detection of parenchymal changes is superior to other imaging methods. High levels of reproducibility are achievable amongst observers who score HRCT lung images. Development of standardized criteria that specify the inclusion/exclusion criteria of patients, pilot testing, and training investigators through review of disagreements, were possibilities suggested for decreasing inter/intra observer variability. Factors affecting the image attenuation (Hounsfield numbers) and thus, the reproducibility of CT densitometric measurements were of minimal influence. Studies have reported on how lung tissue images, derived by HRCT, can be scored and graded. There does not seem to be a golden standard for evaluating these images, which makes comparison between methods challenging. These scoring systems assess the presence, severity, and extent of parenchymal change in the lung. HRCT is considered relevant and superior in evaluating disease severity, disease progression, and in evaluating the effects of therapy regimes in the lung. It is, however, not clear to what extent these scoring methods may be implemented for grading PGD. Further efforts could be made to standardize scoring methods for lung tissue with regards to PGD.

Radiological patterns of primary graft dysfunction after lung transplantation evaluated by 64-multi-slice computed tomography: a descriptive study

We evaluated the diagnostic value of high-resolution computed tomography (HRCT) images generated from 64 detector multi-slice CT scanners (HRCT(64-MSCT) imaging) in relation to primary graft dysfunction (PGD) after lung-transplantation (LUTX) in a pilot study. PGD has mortality rates ranging from 17 to 50% over a 90-day period. Detailed HRCT lung images, reconstructed using 64-MSCT, may aid diagnostic and therapeutic efforts in PGD. Thirty-two patients were scanned four times within a year post-LUTX, in a single-centre prospective study. HRCT lung images were reviewed, evaluated and scored by two observers, for ground-glass (GG) opacities, consolidation, septal thickening (ST) and pulmonary embolism. Image and PGD scores were compared in each patient. GG and consolidation changes were largely present up until 2 weeks post-LUTX, and markedly reduced by the 12th week. ST was predominantly found in patients with PGD. There were no vascular changes found at CT angiographies. The most severe cases of GG opacities and consolidation were found in patients with PGD. ST seems to be an important indicator of PGD. HRCT(64-MSCT) imaging may be a useful tool for the identification of pathological features of PGD not detected by classical evaluation in patients undergoing LUTX.

Limited value of novel pulmonary embolism biomarkers in patients with coronary atherosclerosis.

Background:  Recent research supports the efficacy of various plasma biomarkers in diagnosing pulmonary embolism (PE) including E‐selectin, MMP‐9, MPO, sVCAM‐1, sICAM‐1, adiponectin, hs‐CRP and tPAI‐1.