CT and PET/CT Hybrid Imaging of Coronary Artery Disease

Coronary artery disease (CAD) is a chronic process that evolves over decades and may culminate in myocardial infarction (MI). While invasive coronary angiography (ICA) is still considered the gold standard of imaging CAD, non-invasive assessment of both the vascular anatomy and myocardial perfusion has become an intriguing alternative. In particular, computed tomography (CT) and positron emission tomography (PET) form an attractive combination for such studies. Increased radiation dose is, however, a concern. Our aim in the current thesis was to test novel CT and PET techniques alone and in hybrid setting in the detection and assessment of CAD in clinical patients. Along with diagnostic accuracy, methods for the reduction of the radiation dose was an important target. The study investigating the coronary arteries of patients with atrial fibrillation (AF) showed that CAD may be an important etiology of AF because a high prevalence of CAD was demonstrated within AF patients. In patients with suspected CAD, we demonstrated that a sequential, prospectively ECG-triggered CT technique was applicable to nearly 9/10 clinical patients and the radiation dose was over 60% lower than with spiral CT. To detect the functional significance of obstructive CAD, a novel software for perfusion quantification, CarimasTM, showed high reproducibility with 15O-labelled water in PET, supporting feasibility and good clinical accuracy. In a larger cohort of 107 patients with moderate 30-70% pre-test probability of CAD, hybrid PET/CT was shown to be a powerful diagnostic method in the assessment of CAD with diagnostic accuracy comparable to that of invasive angiography and fractional flow reserve (FFR) measurements. A hybrid study may be performed with a reasonable radiation dose in a vast majority of the cases, improving the performance of stand-alone PET and CT angiography, particularly when the absolute quantification of the perfusion is employed. These results can be applied into clinical practice and will be useful for daily clinical diagnosis of CAD.Siirretty Doriast

Improving traffic safety in Äänekoski factory area

Tässä tutkimuksessa käsitellään Äänekosken tehdasalueen liikennettä ja sen turvallisuutta. Tavoitteena tutkimuksessa on selvittää liikennejärjestelmän nykytilanne, sekä selvittää siihen liittyviä vaaroja ja ongelmia. Tärkeimpänä tavoitteena tutkimuksessa on suunnitella toimenpiteitä, joilla voidaan parantaa tehdasalueen liikenneturvallisuutta. Toimenpiteet ovat pääasiassa täysin uusia suunnitelmia tai ratkaisumalleja, joilla voidaan ratkaista jonkin tietyn alueen ongelmakohdat. Tutkimuksen alussa esitellään lyhyesti Äänekosken tehdasalue ja sen historia. Lisäksi tehdään lyhyt esittely alueen tärkeimmistä ja suurimmista yrityksistä. Teoriaosuudessa tarkastellaan työpaikan liikennettä ja sen turvallisuutta koskevaa lainsäädäntöä. Tärkeimpiä lakeja tutkimuksessa ovat työturvallisuuslaki, tieliikennelaki, rautatielaki sekä valtioneuvoston asetus työpaikkojen turvallisuus- ja terveysvaatimuksista. Teoriaosuudessa käydään lisäksi läpi liikenneturvallisuutta sisältäviä ohjeistuksia ja toimivia käytäntöjä. Tarkastelulla varmistetaan, mitä velvoitteita tulee ottaa huomioon, kun suunnitellaan toimivaa ja turvallista liikennettä. Tutkimusmenetelmät ja aineisto luvussa kuvataan tutkimuksessa käytetyt menetelmät sekä eritellään tutkimuksen eri vaiheet. Tärkeimmät tutkimusmenetelmät olivat turvallisuushavaintojen ja vaaratilanneilmoitusten tarkastelu, logistiset analyysit, riskien arvioinnit, haastattelut sekä kyselyjen laatimiset. Lisäksi tutkimuksen alussa käytettiin aikaa tehdasalueeseen sekä siellä työskentelevien ihmisten tutustumiseen, jotta pystyttiin luomaan alustava kuva liikenteen nykytilasta. Tutkimuksessa tarkasteltavan tehdasalueen keskeisimmät vaarat liittyivät tasoristeyksiin, usean eri kuljetuslajin kohtaustilanteisiin, liukkauteen, epäselviin tai puutteellisiin tiemerkintöihin ja puuttuviin ohjeistuksiin tai liikenteenohjauslaitteisiin. Lisäksi ongelmia alueella aiheuttivat muun muassa suuri ajolupien määrä, puuttuvat kevyen liikenteen väylät, valaistuksen puutteet sekä paperitehtaan lakkauttamisesta aiheutunut liikennöintimallin muuttuminen. Tärkeimmiksi toimenpiteiksi tutkimuksessa nousivat esiin muun muassa yhteisen ajolupakäytännön luominen, kevyen liikenteen väylien lisääminen, tiemaalausten lisääminen ja korjaaminen, tehdasalueen läpi kulkevan kevyen liikenteen rajoittaminen ja uudelleenohjaaminen sekä pyöräilyn turvallisuuden lisääminen. Tutkimuksen jälkeen Äänekosken tehdasalueen yritykset voivat päättää toteutettavista toimenpiteistä sen mukaan, mitä kokevat tarpeellisiksi. Tutkimuksessa toimenpiteet on jaoteltu joko toteutettavaksi nopealla aikataululla tai vasta myöhemmin tulevaisuudessa. Tällä hetkellä tehdasalue elää paperitehtaan lakkautumisesta aiheutunutta murrosta, joka tulee vaikuttamaan sisäisen liikenteen kasvuun kartonkitehtaan laajentaessa toimintaansa. Tämän vuoksi on tärkeää tarkastella alueen liikenteen toimivuutta myös jatkossa ja huomioida tutkimuksessa esitetyt toimenpiteet ja ongelmat liikenneturvallisuuden varmistamiseksi

Comparison of standardized uptake values between Tc-99m-HDP SPECT/CT and F-18-NaF PET/CT in bone metastases of breast and prostate cancer

Background: Despite recent technological advances allowing for quantitative single-photon emission computed tomography (SPECT), quantitative SPECT has not been widely used in the clinical practice. The aim of this study is to evaluate the feasibility of quantitative SPECT for measuring metastatic bone uptake in breast and prostate cancer by comparing standard uptake values (SUVs) measured with Tc-99m-HDP SPECT/CT and F-18-NaF PET/CT.Methods: Twenty-six breast and 27 prostate cancer patients at high risk of bone metastases underwent both Tc-99m-HDP SPECT/CT and F-18-NaF PET/CT within 14days of each other. The SPECT and PET data were reconstructed using ordered-subset expectation-maximization algorithms achieving quantitative images. Metastatic and benign skeletal lesions visible in both data sets were identified, and their maximum, peak, and mean SUVs (SUVmax, SUVpeak, and SUVmean) were determined. SUV ratios (SUVRs) between the lesions and adjacent normal appearing bone were also calculated. Linear regression was used to evaluate the correlations between the SUVs of SPECT and PET and Bland-Altman plots to evaluate the differences between the SUVs and SUVRs of SPECT and PET.Results: A total of 231 skeletal lesions, 129 metastatic and 102 benign, were analyzed. All three SUV measures correlated very strongly between SPECT and PET (R(2)0.80, pConclusion: The strong correlation between SUVs and similar SUVRs of Tc-99m-HDP SPECT/CT and F-18-NaF PET/CT demonstrate that SPECT is an applicable tool for clinical quantification of bone metabolism in osseous metastases in breast and prostate cancer patients.</div

The Clinical Impact of Using 18F-FDG-PET/CT in the Diagnosis of Suspected Vasculitis: The Effect of Dose and Timing of Glucocorticoid Treatment

18F-Fluorodeoxyglucose positron-emission tomography (18F-FDG-PET) with computed tomography (CT) is effective for diagnosing large vessel vasculitis, but its usefulness in accurately diagnosing suspected, unselected vasculitis remains unknown. We evaluated the feasibility of 18F-FDG-PET/CT in real-life cohort of patients with suspicion of vasculitis. The effect of the dose and the timing of glucocorticoid (GC) medication on imaging findings were in special interest. 82 patients with suspected vasculitis were evaluated by whole-body 18F-FDG-PET/CT. GC treatment as prednisolone equivalent doses at the scanning moment and before imaging was evaluated. 38/82 patients were diagnosed with vasculitis. Twenty-one out of 38 patients had increased 18F-FDG accumulation in blood vessel walls indicating vasculitis in various sized vessels. Vasculitis patients with a positive vasculitis finding in 18F-FDG-PET/CT had a significantly shorter duration of GC use (median = 4.0 vs 7.0 days, ), and they used lower GC dose during the PET scan (median dose = 15.0 mg/day vs 40.0 mg/day, ) compared to 18F-FDG-PET/CT-negative patients. Vasculitis patients with a positive 18F-FDG-PET/CT result had significantly higher C-reactive protein (CRP) than patients with a negative 18F-FDG-PET/CT finding (mean value = 154.5 vs 90.4 mg/L, ). We found that 18F-FDG-PET/CT positivity was significantly associated with a lower dose and shorter duration of GC medication and higher CRP level in vasculitis patients. 18F-FDG-PET/CT revealed clinically significant information in over half of the patients and was effective in confirming the final diagnosis.</p

Prospective comparison of F-18-PSMA-1007 PET/CT, whole-body MRI and CT in primary nodal staging of unfavourable intermediate- and high-risk prostate cancer

Purpose To prospectively compare F-18-prostate-specific membrane antigen (PSMA)-1007 positron emission tomography (PET)/CT, whole-body magnetic resonance imaging (WBMRI) including diffusion-weighted imaging (DWI) and standard computed tomography (CT), in primary nodal staging of prostate cancer (PCa). Methods Men with newly diagnosed unfavourable intermediate- or high-risk PCa prospectively underwent F-18-PSMA-1007 PET/CT, WBMRI with DWI and contrast-enhanced CT within a median of 8 days. Six readers (two for each modality) independently reported pelvic lymph nodes as malignant, equivocal or benign while blinded to the other imaging modalities. Sensitivity, specificity and accuracy were reported according to optimistic (equivocal lesions interpreted as benign) and pessimistic (equivocal lesions interpreted as malignant) analyses. The reference standard diagnosis was based on multidisciplinary consensus meetings where available histopathology, clinical and follow-up data were used. Results Seventy-nine patients completed all the imaging modalities, except for one case of interrupted WBMRI. Thirty-one (39%) patients had pelvic lymph node metastases, which were detected in 27/31 (87%), 14/31 (45%) and 8/31 (26%) patients by F-18-PSMA-1007 PET/CT, WBMRI with DWI and CT, respectively (optimistic analysis). In 8/31 (26%) patients, only F-18-PSMA-1007 PET/CT detected malignant lymph nodes, while the other two imaging modalities were reported as negative. At the patient level, sensitivity and specificity values for F-18-PSMA-1007 PET/CT, WBMRI with DWI and CT in optimistic analysis were 0.87 (95%CI 0.71-0.95) and 0.98 (95%CI 0.89-1.00), 0.37 (95%CI 0.22-0.55) and 0.98 (95%CI 0.89-1.00) and 0.26 (95%CI 0.14-0.43) and 1.00 (95%CI 0.93-1.00), respectively. Conclusion F-18-PSMA-1007 PET/CT showed significantly greater sensitivity in nodal staging of primary PCa than did WBMRI with DWI or CT, while maintaining high specificity.Peer reviewe

Discrepancies between Radiology Specialists and Residents in Fracture Detection from Musculoskeletal Radiographs

(1) Background: The aim of this study was to compare the competence in appendicular trauma radiograph image interpretation between radiology specialists and residents. (2) Methods: In this multicenter retrospective cohort study, we collected radiology reports from radiology specialists (N = 506) and residents (N = 500) during 2018–2021. As a reference standard, we used the consensus of two subspecialty-level musculoskeletal (MSK) radiologists, who reviewed all original reports. (3) Results: A total of 1006 radiograph reports were reviewed by the two subspecialty-level MSK radiologists. Out of the 1006 radiographs, 41% were abnormal. In total, 67 radiographic findings were missed (6.7%) and 31 findings were overcalled (3.1%) in the original reports. Sensitivity, specificity, positive predictive value, and negative predictive value were 0.86, 0.92, 0.91 and 0.88 respectively. There were no statistically significant differences between radiology specialists’ and residents’ competence in interpretation (p = 0.44). However, radiology specialists reported more subtle cases than residents did (p = 0.04). There were no statistically significant differences between errors made in the morning, evening, or night shifts (p = 0.57). (4) Conclusions: This study found a lack of major discrepancies between radiology specialists and residents in radiograph interpretation, although there were differences between MSK regions and in subtle or obvious radiographic findings. In addition, missed findings found in this study often affected patient treatment. Finally, there are MSK regions where the sensitivity or specificity is below 90%, and these should raise concerns and highlight the need for double reading and should be taken into consideration in radiology education.Peer reviewe

A Prospective Comparison of F-18-prostate-specific Membrane Antigen-1007 Positron Emission Tomography Computed Tomography, Whole-body 1.5 T Magnetic Resonance Imaging with Diffusion-weighted Imaging, and Single-photon Emission Computed Tomography/Computed Tomography with Traditional Imaging in Primary Distant Metastasis Staging of Prostate Cancer (PROSTAGE)

Background: Computed tomography (CT) and bone scintigraphy (BS) are the imaging modalities currently used for distant metastasis staging of prostate cancer (PCa). Objective: To compare standard staging modalities with newer and potentially more accurate imaging modalities. Design, setting, and participants: This prospective, single-centre trial (NCT03537391) enrolled 80 patients with newly diagnosed high-risk PCa (International Society of Urological Pathology grade group >= 3 and/or prostate-specific antigen [PSA] >= 20 and/or cT >= T3; March 2018-June 2019) to undergo primary metastasis staging with two standard and three advanced imaging modalities. Outcome measurements and statistical analysis: The participants underwent the following five imaging examinations within 2 wk of enrolment and without a prespecified sequence: BS, CT, Tc-99m-hydroxymethylene diphosphonate (Tc-99m-HMDP) single-photon emission computed tomography (SPECT)-CT, 1.5 T whole-body magnetic resonance imaging (WBMRI) using diffusion-weighted imaging, and F-18-prostate-specific membrane antigen-1007 (F-18-PSMA-1007) positron emission tomography(PET)-CT. Each modality was reviewed by two independent experts blinded to the results of the prior studies, who classified lesions as benign, equivocal, or malignant. Pessimistic and optimistic analyses were performed to resolve each equivocal diagnosis. The reference standard diagnosis was defined using all available information accrued during at least 12 mo of clinical follow-up. Patients with equivocal reference standard diagnoses underwent MRI and/or CT to search for the development of anatomical correspondence. PSMA PET-avid lesions without histopathological verification were rated to be malignant only if there was a corresponding anatomical finding suspicious for malignancy at the primary or follow-up imaging. Results and limitations: Seventy-nine men underwent all imaging modalities except for one case of interrupted MRI. The median interval per patient between the first and the last imaging study was 8 d (interquartile range [IQR]: 6-9). The mean age was 70 yr (standard deviation: 7) and median PSA 12 ng/mL (IQR:7-23). The median follow-up was 435 d (IQR: 378-557). Metastatic disease was detected in 20 (25%) patients. The imaging modality F-18-PSMA-1007 PET-CT had superior sensitivity and highest inter-reader agreement. The area under the receiver-operating characteristic curve (AUC) values for bone metastasis detection with PSMA PET-CT were 0.90 (95% confidence interval [CI]: 0.85-0.95) and 0.91 (95% CI: 0.87-0.96) for readers 1 and 2, respectively, while the AUC values for BS, CT, SPECT-CT, and WBMRI were 0.71 (95% CI: 0.58-0.84) and 0.8 (95% CI: 0.67-0.92), 0.53 (95% CI: 0.39-0.67) and 0.66 (95% CI: 0.54-0.77), 0.77 (95% CI: 0.65-0.89) and 0.75 (95% CI: 0.62-0.88), and 0.85 (95% CI: 0.74-0.96) and 0.67 (95% CI: 0.54-0.80), respectively, for the other four pairs of readers. The imaging method F-18-PSMA-1007 PET-CT detected metastatic disease in 11/20 patients in whom standard imaging was negative and influenced clinical decision making in 14/79 (18%) patients. In 12/79 cases, false positive bone disease was reported only by PSMA PET-CT. Limitations included a nonrandomised study setting and few histopathologically validated suspicious lesions. Conclusions: Despite the risk of false positive bone lesions, F-18-PSMA-1007 PET-CT outperformed all other imaging methods studied for the detection of primary distant metastasis in high-risk PCa. Patient summary: In this report, we compared the diagnostic performance of conventional and advanced imaging. It was found that F-18-prostate-specific membrane antigen-1007 positron emission tomography/computed tomography (F-18-PSMA-1007 PET-CT) was superior to the other imaging modalities studied for the detection of distant metastasis at the time of initial diagnosis of high-risk prostate cancer. PSMA PET-CT also appears to detect some nonmetastatic bone lesions. (C) 2020 The Author(s). Published by Elsevier B.V. on behalf of European Association of Urology.Peer reviewe

Deep learning accurately classifies elbow joint effusion in adult and pediatric radiographs

Joint effusion due to elbow fractures are common among adults and children. Radiography is the most commonly used imaging procedure to diagnose elbow injuries. The purpose of the study was to investigate the diagnostic accuracy of deep convolutional neural network algorithms in joint effusion classification in pediatric and adult elbow radiographs. This retrospective study consisted of a total of 4423 radiographs in a 3-year period from 2017 to 2020. Data was randomly separated into training (n = 2672), validation (n = 892) and test set (n = 859). Two models using VGG16 as the base architecture were trained with either only lateral projection or with four projections (AP, LAT and Obliques). Three radiologists evaluated joint effusion separately on the test set. Accuracy, precision, recall, specificity, F1 measure, Cohen's kappa, and two-sided 95% confidence intervals were calculated. Mean patient age was 34.4 years (1-98) and 47% were male patients. Trained deep learning framework showed an AUC of 0.951 (95% CI 0.946-0.955) and 0.906 (95% CI 0.89-0.91) for the lateral and four projection elbow joint images in the test set, respectively. Adult and pediatric patient groups separately showed an AUC of 0.966 and 0.924, respectively. Radiologists showed an average accuracy, sensitivity, specificity, precision, F1 score, and AUC of 92.8%, 91.7%, 93.6%, 91.07%, 91.4%, and 92.6%. There were no statistically significant differences between AUC's of the deep learning model and the radiologists (p value > 0.05). The model on the lateral dataset resulted in higher AUC compared to the model with four projection datasets. Using deep learning it is possible to achieve expert level diagnostic accuracy in elbow joint effusion classification in pediatric and adult radiographs. Deep learning used in this study can classify joint effusion in radiographs and can be used in image interpretation as an aid for radiologists