Direct communication between radiologists and patients improves the quality of imaging reports.

OBJECTIVES: We investigate in what percentage of cases and to what extent radiological reports change when radiologists directly communicate with patients after imaging examinations. METHODS: One hundred twenty-two consecutive outpatients undergoing MRI examinations at a single center were prospectively included. Radiological reports of the patients were drafted by two radiologists in consensus using only the clinical information that was made available by the referring physicians. Thereafter, one radiologist talked directly with the patient and recorded the duration of the conversation. Afterwards, the additional information from the patient was used to reevaluate the imaging studies in consensus. The radiologists determined whether the radiological report changed based on additional information and, if yes, to what extent. The degree of change was graded on a 4-point Likert scale (1, non-relevant findings, to 4, highly relevant findings). RESULTS: Following direct communication (duration 170.9 ± 53.9 s), the radiological reports of 52 patients (42.6%) were changed. Of the 52 patients, the degree of change was classified as grade 1 for 8 patients (15.4 %), grade 2 for 27 patients (51.9%), grade 3 for 13 patients (25%), and grade 4 for 4 patients (7.7%). The reasons leading to changes were missing clinical information in 50 cases (96.2%) and the lack of additional external imaging in 2 cases (3.8%). CONCLUSIONS: Radiologists should be aware that a lack of accurate information from the clinician can lead to incorrect radiological reports or diagnosis. Radiologists should communicate directly with patients, especially when the provided information is unclear, as it may significantly alter the radiological report. KEY POINTS: • Direct communication between radiologists and patients for an average of 170's resulted in a change in the radiological reports of 52 patients (42.6%). • Of the 42.6% of cases where the reports were changed, the alterations were highly relevant (grades 3 and 4) in 32.7%, indicating major changes with significant impact towards patient management.

Impact of model-based iterative reconstruction on low-contrast lesion detection and image quality in abdominal CT: a 12-reader-based comparative phantom study with filtered back projection at different tube voltages.

OBJECTIVES: To evaluate the impact of model-based iterative reconstruction (MBIR) on image quality and low-contrast lesion detection compared with filtered back projection (FBP) in abdominal computed tomography (CT) of simulated medium and large patients at different tube voltages. METHODS: A phantom with 45 hypoattenuating lesions was placed in two water containers and scanned at 70, 80, 100, and 120 kVp. The 120-kVp protocol served as reference, and the volume CT dose index (CTDIvol) was kept constant for all protocols. The datasets were reconstructed with MBIR and FBP. Image noise and contrast-to-noise-ratio (CNR) were assessed. Low-contrast lesion detectability was evaluated by 12 radiologists. RESULTS: MBIR decreased the image noise by 24% and 27%, and increased the CNR by 30% and 29% for the medium and large phantoms, respectively. Lower tube voltages increased the CNR by 58%, 46%, and 16% at 70, 80, and 100 kVp, respectively, compared with 120 kVp in the medium phantom and by 9%, 18% and 12% in the large phantom. No significant difference in lesion detection rate was observed (medium: 79-82%; large: 57-65%; P > 0.37). CONCLUSIONS: Although MBIR improved quantitative image quality compared with FBP, it did not result in increased low-contrast lesion detection in abdominal CT at different tube voltages in simulated medium and large patients. KEY POINTS: • MBIR improved quantitative image quality but not lesion detection compared with FBP. • Increased CNR by low tube voltages did not improve lesion detection. • Changes in image noise and CNR do not directly influence diagnostic accuracy.

Enthesopathy of the pectoralis major tendon mimicking osteoid osteoma. A case report with an unfortunate series of events.

BACKGROUND: we present the case of an enthesopathy at the proximal humerus which was initially - due to the clinical history and a positive bone scintigraphy - regarded suspicious for metastatic breast cancer in a 50-year-old woman. CASE REPORT: after complementing radiographs and a magnetic resonance (MR) examination exhibiting a focally contrast enhancing juxtacortical osteolysis of the humerus, a metastasis seemed radiologically unlikely, but besides a traction-related periosteal reaction of the pectoralis major tendon an unusual osteoid osteoma could not unequivocally be ruled out. Although radiological follow-up was recommended the patient insisted on a surgical resection that was performed subsequently and confirmed an enthesopathy. Shortly after, she fractured her upper arm following minor trauma but is doing well after conservative treatment since then. CONCLUSION: enthesopathies presenting as unusual periosteal reactions can mimic primary and secondary bone tumors and should always be included in the differential diagnosis.

Artifacts in dual-energy CT gout protocol: a review of 50 suspected cases with an artifact identification guide.

OBJECTIVE: The objective of our study was to discover the types and incidence of artifacts in dual-energy CT (DECT) using datasets of 50 consecutive patients who underwent a four-limb DECT protocol for the evaluation of suspected gout. Identification of artifacts and techniques for artifact reduction are discussed. CONCLUSION: Artifacts commonly occur in DECT performed for gout assessment but are usually readily recognizable. For 90% of the patients in our study who underwent imaging for suspected gout, DECT showed some type of artifact, with nail bed and skin artifacts being the most common.

Achilles tendinopathy and partial tear diagnosis using dual-energy computed tomography collagen material decomposition application.

Computed tomographic (CT) scans of the ankle and foot are frequently obtained with in-patients with hind foot and ankle pain to identify fractures, arthritis, and bone lesions. Soft tissue detail is limited, however. Dual-energy CT provides additional information on soft tissue structures, including tendons, with no additional radiation dose to the patient. We present a case of an Achilles tendon tear visualized on DECT, which was subsequently confirmed with magnetic resonance imaging.

Image quality in conventional chest radiography. Evaluation using the postprocessing tool Diamond View.

The objective of this work was to evaluate the influence of the postprocessing tool Diamond View (Siemens AG Medical Solutions, Germany) on image quality in conventional chest radiography. Evaluation of image quality remains a challenge in conventional radiography. Based on the European Commission quality criteria we evaluated the improvement of image quality when applying the new postprocessing tool Diamond View (Siemens AG Medical solutions, Germany) to conventional chest radiographs. Three different readers prospectively evaluated 102 digital image pairs of chest radiographs. Statistical analysis was performed with a p value <0.05 considered as significant. Images were evaluated on basis of the modified imaging Quality Criteria by the Commission of the European Communities. Each of the 11 image quality criteria was evaluated separately using a five point classification. Statistical analysis showed an overall tendency for improved image quality for Diamond View (DV) for all criteria. Significant differences could be found in most of the criteria. In conclusion DV improves image quality in conventional chest radiographs.

Pedal angiography in peripheral arterial occlusive disease: first-pass i.v. contrast-enhanced MR angiography with blood pool contrast medium versus intraarterial digital subtraction angiography.

OBJECTIVE: The purpose of this study was to prospectively evaluate first-pass i.v. gadofosveset-enhanced MR angiography in patients with peripheral arterial occlusive disease for visualization of the pedal arteries and stenosis or occlusion of those arteries with intraarterial digital subtraction angiography as the reference standard. SUBJECTS AND METHODS: Twenty patients with peripheral arterial occlusive disease (nine women, 11 men; age-range 58-83 years) were prospectively enrolled. Gadofosveset first-pass contrast-enhanced MR angiography was performed with a 1.5-T system, a dedicated foot coil, and cuff compression to the calf. Arterial segments were assessed for degree of arterial stenosis, arterial visibility, diagnostic utility, and venous contamination. Detection of vessel stenosis or occlusion was evaluated in comparison with findings at digital subtraction angiography. The unpaired Student's t test was used to test arterial visibility with the two techniques. RESULTS: First-pass MR angiography with gadofosveset had good diagnostic utility in 83.9% of all segments and no venous contamination in 96.8% of all segments. There was no difference between the performance of intraarterial digital subtraction angiography and that of i.v. contrast-enhanced MR angiography in arterial visibility overall (p = 0.245) or in subgroup analysis of surgical arterial bypass targets (p = 0.202). The overall sensitivity, specificity, and accuracy of i.v. gadofosveset-enhanced MR angiography for characterization of clinically significant stenosis and occlusion were 91.4%, 96.1%, and 93.9%. In the subgroup analysis, the sensitivity, specificity, and accuracy were 85.5%, 96.5%, and 92.1%. CONCLUSION: Gadofosveset-enhanced MR angiography of the pedal arteries in patients with peripheral arterial occlusive disease has arterial visibility equal to that of digital subtraction angiography and facilitates depiction of clinically significant stenosis and occlusion.

Dynamic magnetic resonance angiography of the arteries of the hand. A comparison between an extracellular and an intravascular contrast agent.

The purpose of this study was to compare the image quality of the intravascular contrast agent gadofosveset with the extracellular contrast agent gadoterate meglumine in time-resolved three-dimensional magnetic resonance (MR) angiography of the human arteries of the hand. The value of cuff compression technique for suppression of venous enhancement for both contrast agents was also investigated. Three-dimensional MR angiograms of both hands of 11 healthy volunteers were acquired for each contrast agent at 1.5-T, while subsystolic cuff compression was applied at one side. Quantitative and qualitative evaluation were performed and analyzed with Student's t-test. Visualization of vessels was superior in the images acquired with gadofosveset, especially in the late phases. Quantitative and qualitative evaluation showed significantly higher values for gadofosveset. The cuff compression at the lower arm proved to be an effective method to enhance arterial vessels. In conclusion the blood pool agent gadofosveset is superior for the dynamic imaging of the vessels of the hand when compared with the extracellular contrast agent gadoterate meglumine. To fully utilize the advantages of intravascular contrast agents, venous overlay has to be delayed or reduced, which can be achieved effectively by subsystolic lower arm cuff compression.

Image quality in conventional lumbar spine radiography: evaluation using the post-processing tool Diamond View.

Conventional radiography contributes for the majority of examinations in radiology departments. Based on the European Commission Quality Criteria we evaluated the effects on image quality when applying the new post-processing tool Diamond View (Siemens AG Medical Solutions, Germany) to conventional lumbar spine radiographs. 100 digital image pairs in two directions in two planes of lumbar spine radiographs were prospectively evaluated by two radiologists. Statistical analysis was performed with a p-value<.05 considered as significant. Images were evaluated on basis of the modified imaging Quality Criteria by the Commission of the European Communities, rated on a five-point scale. Statistical analysis showed an overall tendency for improved image quality of Diamond View (DV) for all criteria. Significant differences could be found in most of the criteria. Additional phantom analyses supported the advantage of DV. In conclusion DV improves image quality in conventional lumbar spine radiographs.

The C-terminal transmembrane region of synaptobrevin binds synaptophysin from adult synaptic vesicles.

Synaptophysin and synaptobrevin are abundant membrane proteins of neuronal small synaptic vesicles. In mature, differentiated neurons they form the synaptophysin/synaptobrevin (Syp/Syb) complex. Synaptobrevin also interacts with the plasma membrane-associated proteins syntaxin and SNAP25, thereby forming the SNARE complex necessary for exocytotic membrane fusion. The two complexes are mutually exclusive. Synaptobrevin is a C-terminally membrane-anchored protein with one transmembrane domain. While its interaction with its SNARE partners is mediated exclusively by its N-terminal cytosolic region it has been unclear so far how binding to synaptophysin is accomplished. Here, we show that synaptobrevin can be cleaved in its synaptophysin-bound form by tetanus toxin and botulinum neurotoxin B, or by botulinum neurotoxin D, leaving shorter or longer C-terminal peptide chains bound to synaptophysin, respectively. A recombinant, C-terminally His-tagged synaptobrevin fragment bound to nickel beads specifically bound synaptophysin, syntaxin and SNAP25 from vesicular detergent extracts. After cleavage by tetanus toxin or botulinum toxin D light chain, the remaining C-terminal fragment no longer interacted with syntaxin or SNAP 25. In contrast, synaptophysin was still able to bind to the residual C-terminal synaptobrevin cleavage product. In addition, the His-tagged C-terminal synaptobrevin peptide 68-116 was also able to bind synaptophysin in detergent extracts from adult brain membranes. These data suggest that synaptophysin interacts with the C-terminal transmembrane part of synaptobrevin, thereby allowing the N-terminal cytosolic chain to interact freely with the plasma membrane-associated SNARE proteins. Thus, by binding synaptobrevin, synaptophysin may positively modulate neurotransmission.

Botulinum neurotoxin type D enables cytosolic delivery of enzymatically active cargo proteins to neurones via unfolded translocation intermediates.

Multi-domain bacterial protein toxins are being explored as potential carriers for targeted delivery of biomolecules. Previous approaches employing isolated receptor binding subunits disallow entry into the cytosol. Strategies in which catalytic domains are replaced with cargo molecules are presumably inefficient due to co-operation of domains during the endosomal translocation step. Here, we characterize a novel transport vehicle in which cargo proteins are attached to the amino terminus of the full-length botulinum neurotoxin type D (BoNT/D). The intrinsic enzymatic activity of the neurotoxin allowed quantification of the efficacy of cargo delivery to the cytosol. Dihydrofolate reductase and BoNT type A (BoNT/A) light chain (LC) were efficiently conveyed into the cytosol, whereas attachment of firefly luciferase or green fluorescent protein drastically reduced the toxicity. Luciferase and BoNT/A LC retained their catalytic activity as evidenced by luciferin conversion or SNAP-25 hydrolysis in the cytosol of synaptosomes, respectively. Conformationally stabilized dihydrofolate reductase as cargo considerably decreased the toxicity indicative for the requirement of partial unfolding of cargo protein and catalytic domain as prerequisite for efficient translocation across the endosomal membrane. Thus, enzymatically inactive clostridial neurotoxins may serve as effective, safe carriers for delivering proteins in functionally active form to the cytosol of neurones.

The synaptophysin/synaptobrevin complex dissociates independently of neuroexocytosis.

Synaptophysin is one of the most abundant membrane proteins of small synaptic vesicles. In mature nerve terminals it forms a complex with the vesicular membrane protein synaptobrevin, which appears to modulate synaptobrevin's interaction with the plasma membrane-associated proteins syntaxin and SNAP25 to form the SNARE complex as a prerequisite for membrane fusion. Here we show that synaptobrevin is preferentially cleaved by tetanus toxin while bound to synaptophysin or when existing as a homodimer. The synaptophysin/synaptobrevin complex is, however, not affected when neuronal secretion is blocked by botulinum A toxin which cleaves SNAP25. Excessive stimulation with alpha-latrotoxin or Ca(2+)-ionophores dissociates the synaptophysin/synaptobrevin complex and increases the interaction of the other SNARE proteins. The stimulation-induced dissociation of the synaptophysin/synaptobrevin complex is not inhibited by pre-incubating neurones with botulinum A toxin, but depends on extracellular calcium. However, the synaptophysin/synaptobrevin complex cannot be directly dissociated by calcium alone or in combination with magnesium. The dissociation of synaptobrevin from synaptophysin appears to precede its interaction with the other SNARE proteins and does not depend on the final fusion event. This finding further supports the modulatory role the synaptophysin/synaptobrevin complex may play in mature neurones.

The synaptophysin/synaptobrevin interaction critically depends on the cholesterol content.

Synaptophysin interacts with synaptobrevin in membranes of adult small synaptic vesicles. The synaptophysin/synaptobrevin complex promotes synaptobrevin to built up functional SNARE complexes thereby modulating synaptic efficiency. Synaptophysin in addition is a cholesterol-binding protein. Depleting the membranous cholesterol content by filipin or beta-methylcyclodextrin (beta-MCD) decreased the solubility of synaptophysin in Triton X-100 with less effects on synaptobrevin. In small synaptic vesicles from rat brain the synaptophysin/synaptobrevin complex was diminished upon beta-MCD treatment as revealed by chemical cross-linking. Mice with a genetic mutation in the Niemann-Pick C1 gene developing a defect in cholesterol sorting showed significantly reduced amounts of the synaptophysin/synaptobrevin complex compared to their homo- or heterozygous littermates. Finally when using primary cultures of mouse hippocampus the synaptophysin/synaptobrevin complex was down-regulated after depleting the endogenous cholesterol content by the HMG-CoA-reductase inhibitor lovastatin. Alternatively, treatment with cholesterol up-regulated the synaptophysin/synaptobrevin interaction in these cultures. These data indicate that the synaptophysin/synaptobrevin interaction critically depends on a high cholesterol content in the membrane of synaptic vesicles. Variations in the availability of cholesterol may promote or impair synaptic efficiency by interfering with this complex.