Importance of Diagnostic Imaging Training for Intensivists: Lessons Learned From a Case.

Intensive care physicians are tasked with managing patients with complex organ disorders, necessitating a broad skill set and ongoing education. While simulation training often focuses on equipment handling, this case report highlights a critical instance of acute aortic dissection initially missed on imaging during intensive care unit (ICU) admission. An 86-year-old woman with multiple comorbidities presented with respiratory symptoms and electrolyte imbalances, ultimately requiring ICU admission. Despite initial inconclusive imaging and treatment for suspected conditions, further evaluation revealed a dissecting aneurysm of the descending aorta. This case underscores the importance of thorough diagnostic evaluation and ongoing vigilance, especially in older adults with multiple health conditions. It emphasizes the need for comprehensive education, including proactive training in image diagnosis, to recognize diverse medical presentations and potential complications. This case serves as a reminder of the evolving challenges in critical care and the necessity for continuous education and adaptability to ensure optimal patient outcomes.

Bronchiolitis Obliterans With Recurrent Pneumothorax After Allogeneic Bone Marrow Transplantation.

Bronchiolitis obliterans syndrome (BOS) is a non-infectious pulmonary complication that can occur in patients who have undergone allogeneic bone marrow transplantation (BMT). BOS is characterized by the irreversible narrowing and obstruction of bronchi, resulting in severe respiratory distress and poor outcomes. This case report focuses on the complex management of a patient with a multifaceted medical history. A 20-year-old man was initially diagnosed with precursor B lymphoblastic lymphoma and subsequently underwent allogeneic BMT. Nine months later, the patient was diagnosed with bronchiolitis obliterans with graft-versus-host disease, resulting in the development of BOS. Remarkably, 12 years after BMT, the patient was registered for lung transplantation. However, one year after registration, the patient developed a left pneumothorax. Despite rigorous efforts, including continuous thoracic drainage and autologous pleurodesis, the pneumothorax did not respond to treatment and required video-assisted thoracic surgery (VATS) bullectomy. The preoperative assessment revealed a challenging clinical finding characterized by the need for home oxygen therapy (5 L/min with a nasal cannula), severe Hugh-Jones classification IV-V, and marked hypercapnia (partial pressure of carbon dioxide (pCO2), 76 mmHg). Imaging studies, including high-resolution computed tomography and chest radiography, revealed hyperinflation, emphysematous changes, and bronchiectasis across all lung lobes, further complicating the patient's condition. Intraoperative management had the unique challenges of persistent hypoxia (P/F ratio 65-80), positive end-expiratory pressure of 5 cmH2O, and low tidal volumes (1.6-2.0 mL/kg) during one-lung ventilation. To address these problems, both-lung ventilation had to be performed intermittently. However, hyperventilation remained unmanageable, with maximum pCO2 values reaching 140 mmHg. Following surgery, the patient had to be admitted to the intensive care unit in an intubated state. Fortunately, the following day, the patient's condition improved markedly, his state of consciousness was clear (Glasgow Coma Scale 15) and his pCO2 level improved (66 mmHg) with spontaneous breath. This course of events allowed extubation and the patient was discharged to the general ward only two days after surgery. This case highlights the critical importance of a comprehensive preoperative assessment, including advanced imaging, when managing patients with BOS and complex pulmonary complications. Furthermore, it highlights the complexity and difficulty of perioperative respiratory management in such cases.

A suicide attempt by intramuscular injection of pentobarbital sodium into rectus abdominis suggested by computed tomography.

Suicide attempts in humans due to injections of the veterinary drug pentobarbital sodium have been rarely reported. Herein, we present a case of a suicide attempt by intramuscular injection of pentobarbital sodium into the rectus abdominis muscle, which was suggested by computed tomography (CT). A 73-year-old man was brought to the emergency department with GCS 3 (E1V1M1) and an incised wound on the right side of the neck. A bottle of Somnopentyl® (pentobarbital sodium, 64.8 mg/ml), a 20-ml empty syringe with an 18-mm needle, and no. 10 scalpel were present at the scene. At the emergency department, the patient was intubated and was admitted to the intensive care unit. A urine drug screen test by SIGNIFY® ER was positive for benzodiazepines and barbiturates, and continuous veno-venous hemofiltration (CHF) was initiated. The route of drug administration was initially unknown; however, a CT scan revealed swelling of the left rectus abdominis muscle with a wound suggestive of a needle puncture, and the CT analysis suggested 38.16 ml as the maximum dose of pentobarbital sodium. On day 3, the patient's consciousness improved, and he was weaned off CHF and mechanical ventilation. There have been several reports of postmortem CT yielding information on the site of administration of intoxicants, but there have been none for surviving intoxicated patients. This is the first report of the usefulness of CT to identify the site of administration of the causative agent of intoxication while the patient is still alive.

Deep-learning algorithm to detect fibrosing interstitial lung disease on chest radiographs.

BACKGROUND: Antifibrotic therapies are available to treat chronic fibrosing interstitial lung diseases (CF-ILDs), including idiopathic pulmonary fibrosis. Early use of these treatments is recommended to slow deterioration of respiratory function and to prevent acute exacerbation. However, identifying patients in the early stages of CF-ILD using chest radiographs is challenging. In this study, we developed and tested a deep-learning algorithm to detect CF-ILD using chest radiograph images. METHOD: From the image archive of Sapporo Medical University Hospital, 653 chest radiographs from 263 patients with CF-ILDs and 506 from 506 patients without CF-ILD were identified; 921 were used for deep learning and 238 were used for algorithm testing. The algorithm was designed to output a numerical score ranging from 0 to 1, representing the probability of CF-ILD. Using the testing dataset, the algorithm's capability to identify CF-ILD was compared with that of doctors. A second dataset, in which CF-ILD was confirmed using computed tomography images, was used to further evaluate the algorithm's performance. RESULTS: The area under the receiver operating characteristic curve, which indicates the algorithm's detection capability, was 0.979. Using a score cut-off of 0.267, the sensitivity and specificity of detection were 0.896 and 1.000, respectively. These data showed that the algorithm's performance was noninferior to that of doctors, including pulmonologists and radiologists; performance was verified using the second dataset. CONCLUSIONS: We developed a deep-learning algorithm to detect CF-ILDs using chest radiograph images. The algorithm's detection capability was noninferior to that of doctors.

Correlation between the hysteresis of the pressure-volume curve and the recruitment-to-inflation ratio in patients with coronavirus disease 2019.

BACKGROUND: Since the response to lung recruitment varies greatly among patients receiving mechanical ventilation, lung recruitability should be assessed before recruitment maneuvers. The pressure-volume curve (PV curve) and recruitment-to-inflation ratio (R/I ratio) can be used bedside for evaluating lung recruitability and individualing positive end-expiratory pressure (PEEP). Lung tissue recruitment on computed tomography has been correlated with normalized maximal distance (NMD) of the quasi-static PV curve. NMD is the maximal distance between the inspiratory and expiratory limb of the PV curve normalized to the maximal volume. However, the relationship between the different parameters of hysteresis of the quasi-static PV curve and R/I ratio for recruitability is unknown. METHODS: We analyzed the data of 33 patients with severe coronavirus disease 2019 (COVID-19) who received invasive mechanical ventilation. Respiratory waveform data were collected from the ventilator using proprietary acquisition software. We examined the relationship of the R/I ratio, quasi-static PV curve items such as NMD, and respiratory system compliance (Crs). RESULTS: The median R/I ratio was 0.90 [interquartile range (IQR), 0.70-1.15] and median NMD was 41.0 [IQR, 37.1-44.1]. The NMD correlated significantly with the R/I ratio (rho = 0.74, P < 0.001). Sub-analysis showed that the NMD and R/I ratio did not correlate with Crs at lower PEEP (- 0.057, P = 0.75; and rho = 0.15, P = 0.41, respectively). On the contrary, the ratio of Crs at higher PEEP to Crs at lower PEEP (Crs ratio (higher/lower)) moderately correlated with NMD and R/I ratio (rho = 0.64, P < 0.001; and rho = 0.67, P < 0.001, respectively). CONCLUSIONS: NMD of the quasi-static PV curve and R/I ratio for recruitability assessment are highly correlated. In addition, NMD and R/I ratio correlated with the Crs ratio (higher/lower). Therefore, NMD and R/I ratio could be potential indicators of recruitability that can be performed at the bedside.

Pneumomediastinum as patient self-inflicted lung injury in patients with acute respiratory distress syndrome due to COVID-19: a case series.

Background: In patients with coronavirus disease (COVID-19) due to severe acute respiratory syndrome coronavirus 2 infection, pneumomediastinum has been increasingly reported in cases of noninvasive oxygen therapy, including high-flow nasal cannula, and invasive mechanical ventilation. However, its pathogenesis is still not understood. Case Presentation: We report two cases of pneumomediastinum in acute respiratory distress syndrome (ARDS) caused by COVID-19. In both cases, control of spontaneous breathing with neuromuscular blocking agents resulted in resolution of pneumoperitoneum. Conclusion: The improvement of pneumomediastinum with control of spontaneous breathing suggested patient self-inflicted lung injury as a possible mechanism in this case series. In ARDS cases with pneumomediastinum, in addition to controlling plateau pressure with conventional lung protective ventilation, spontaneous breathing should be controlled if the patient's inspiratory effort is suspected to be strong.

Diagnosis of prosthetic joint infection at the hip using the standard uptake value of three-phase 99mTc-hydroxymethylene diphosphonate SPECT/CT.

PURPOSE: To retrospectively investigate whether the standard uptake value (SUV) of 99mTc-bone single-photon emission computed tomography (SPECT)/CT could be useful for predicting prosthetic joint infection (PJI) at the hip. PATIENTS AND METHODS: We analyzed the cases of 37 patients with a suspected PJI at the hip who underwent 99mTc-bone SPECT/CT and surgical intervention with pathological and bacterial examinations. We divided the cases into those with and those without a causative bacterium detected in a surgical specimen, i.e., the positive bacterial culture (PBC) group (n = 17) and negative bacterial culture (NBC) group (n = 20). Cases with neutrophilic infiltration of surgical specimen comprised the positive neutrophilic infiltration (PINF) group (n = 18) and those without INF comprised the non-neutrophilic infiltration (NINF) group (n = 19). Quantitative analyses were performed using maximum SUVs and peak SUVs of blood-pool (BP) phase images (SUVmaxBP and SUVpeakBP) and late (LT)-phase images (SUVmaxLT and SUVpeakLT). RESULTS: Regarding the bacterial cultures, there were significant differences between the PBC and NBC groups in SUVmaxBP (5.26 ± 1.49 vs. 4.21 ± 1.15, respectively; p = 0.019), SUVpeakBP (4.89 ± 1.32 vs. 3.87 ± 1.06, p = 0.012), SUVmaxLT (16.10 ± 6.36 vs. 11.67 ± 4.95, p = 0.026), and SUVpeakLT (14.58 ± 5.83 vs. 10.49 ± 4.31 p = 0.036). Regarding neutrophilic infiltration, there were significant differences between the PINF and NINF groups in SUVmaxBP (5.18 ± 1.48 vs. 4.24 ± 1.19, p = 0.047) and SUVpeakBP (4.78 ± 1.32 vs. 3.92 ± 1.10, p = 0.043). CONCLUSION: An SUV analysis of 99mTc-bone SPECT/CT is a useful method to differentiate a PJI at the hip from non-infection.

Self-correction of a migrated power-injectable peripherally inserted central catheter following contrast-enhanced computed tomography.

The use of power-injectable peripherally inserted central catheter (PIPICC) is a common practice, but displacement of these lines following injection of contrast media has been reported in 15.4% of cases. This report presents imaging evidence of displacement and self-correction of a PIPICC line following contrast-enhanced computed tomography.

Abnormal [18F]fluorodeoxyglucose accumulation to tori tubarius in IgG4-related disease.

OBJECTIVES: Tubarial glands (TGs) are recently refocused gland tissues localized near the tori tubarius in the nasopharynx and their clinical relevance is not clear yet. IgG4-related disease (IgG4-RD) is a progressive fibrosing condition and salivary glands are well-affected lesions. The aim of the present study is to examine [18F]fluorodeoxyglucose ([18F]FDG) accumulation to the tori tubarius in IgG4-related disease (IgG4-RD). METHODS: 48 patients with IgG4-RD who underwent positron emission tomography (PET) scanning with [18F]FDG were included and semi-quantitative analysis of [18F]FDG accumulation to tori tubarius was performed along with the clinical features and histopathological analysis. RESULTS: Of the 48 patients, abnormal [18F]FDG accumulation (metabolic tumour volume ≥ 1) to tori tubarius was observed in 15 (31.3%), all of whom had lesions in other head and neck glands. IgG4-RD patients with abnormal [18F]FDG accumulation to tori tubarius showed swollen nasopharyngeal walls around tori tubarius and forceps biopsy of the lesion revealed acinar cells and IgG4-positive plasma cells histologically. Abnormal [18F]FDG accumulation (maximum standard uptake value, metabolic tumour volume and total lesion glycolysis) to tori tubarius correlated with higher IgG4 and lower IgA serum concentrations. CONCLUSIONS: Abnormal [18F]FDG accumulation to tori tubarius can be observed in patients with IgG4-RD and the abnormal [18F]FDG accumulation to tori tubarius can be a clue of TG involvement in IgG4-RD.

Therapeutic Evaluation of Computed Tomography Findings for Efficacy of Prone Ventilation in Acute Respiratory Distress Syndrome Patients with Abdominal Surgery.

INTRODUCTION: In Acute Respiratory Distress Syndrome (ARDS), the heterogeneity of lung lesions results in a mis-match between ventilation and perfusion, leading to the development of hypoxia. The study aimed to examine the association between computed tomographic (CT scan) lung findings in patients with ARDS after abdominal surgery and improved hypoxia and mortality after prone ventilation. MATERIAL AND METHODS: A single site, retrospective observational study was performed at the Sapporo Medical University School of Medicine, Sapporo, Hokkaido, Japan, between 1st January 2004 and 31st October 2018. Patients were allocated to one of two groups after CT scanning according to the presence of ground-glass opacity (GGO) or alveolar shadow with predominantly dorsal lung atelectasis (DLA) on lung CT scan images. Also, Patients were divided into a prone ventilation group and a supine ventilation group when the treatment for ARDS was started. RESULTS: We analyzed data for fifty-one patients with ARDS following abdominal surgery. CT scans confirmed GGO in five patients in the Group A and in nine patients in the Group B, and DLA in 17 patients in the Group A and nine patients in the Group B. Both GGO and DLA were present in two patients in the Group A and nine patients in the Group B. Prone ventilation significantly improved patients' impaired ratio of arterial partial pressure of oxygen to fraction of inspired oxygen from 12 h after prone positioning compared with that in the supine position. Weaning from mechanical ventilation occurred significantly earlier in the Group A with DLA vs the Group B with DLA (P < 0.001). Twenty-eight-day mortality was significantly lower for the Group A with DLA vs the Group B with DLA (P = 0.035). CONCLUSIONS: These results suggest that prone ventilation could be effective for treating patients with ARDS as showing the DLA.

[Impact of Misregistration between the Myocardial Perfusion Images and CT Attenuation Correction Map on the %up Take with 17 Segments Polar Map].

PURPOSE: Computed tomography (CT) attenuation correction of myocardial perfusion in single-photon emission computed tomography (SPECT) /CT systems is possibility of misregistration between emission and transmission scans. This study aimed to evaluate the influence of misregistration using a polar map of 17 segments model. METHODS: Using the fusion software, we assessed the magnitude and direction of misregistration in 200 consecutive myocardial perfusion SPECT images with 99mTechnetium (99mTc) tetrofosmin. After registration, CT data was shifted by ±1, ±2, and ±3 pixels along the cephalad/caudal, dorsal/ventral, and left/right axes, respectively. The registered image was compared with the shifted image. RESULTS: Misregistration between the SPECT and CT images occurred by 1-2 pixels in 127 cases (63.5%) and by 2 or more pixels in four cases (2%); the maximum misregistration was 1.2±0.4 pixels on average. The polar map scoring was most significantly affected by 3 pixel ventral shift. A ventral shift of 1 pixel affected the scores for the anterolateral and inferolateral segments, whereas a caudal shift of 1 pixel affected the scores for the anterior segment. CONCLUSION: Since the 17 segments model can evaluate the position more precisely than the five segments model, it is possible to evaluate up to 1 pixel misregistration.

Repeatability analysis of ADC histogram metrics of the uterus.

BACKGROUND: Recently, histogram analysis based on voxel-wise apparent diffusion coefficient (ADC) value distribution has been increasingly performed. However, few studies have been reported regarding its repeatability. PURPOSE: To evaluate the repeatability of ADC histogram metrics of the uterus in clinical magnetic resonance imaging (MRI). MATERIAL AND METHODS: Thirty-three female patients who underwent pelvic MRI including diffusion-weighted imaging (DWI) were prospectively included after providing informed consent. Two sequential DWI acquisitions with identical parameters and position were obtained. Regions of interest (ROIs) for histologically confirmed uterine lesions (five cervical and three endometrial cancers, and one endometrial hyperplasia) and normal appearing tissues (21 endometrium and 33 myometrium) were assigned on the first DWI dataset and then pasted onto the second DWI dataset. ADC histogram metrics within the ROIs were calculated and repeatability was evaluated by calculating within-subject coefficient of variance (%) (wCV (%)) and Bland-Altman plot (%). RESULTS: ADC 10%, 25%, median, 75%, 90%, maximum, mean, and entropy showed high repeatability (wCV (%) < 7, 95% limit of agreement in Bland-Altman plot (%) < ±20), followed by ADC minimum (wCV (%) = 8.12, 95% limit of agreement in Bland-Altman plot (%) < ±30). However, ADC skewness and kurtosis showed very low repeatability in all evaluations. CONCLUSION: ADC histogram metrics like ADC 10%, 25%, median, 75%, 90%, maximum, mean, and entropy are robust biomarkers and could be applicable to clinical use. However, ADC skewness and kurtosis lack robustness. Radiologists should keep these characteristics and limitations in mind when interpreting quantitative DWI.

Traumatic Basilar Artery Entrapment without Longitudinal Clivus Fracture: A Case Report and Review of the Literature.

In blunt cerebrovascular injury, reported traumatic basilar artery occlusions have involved dissection of the basilar artery, distal embolization due to traumatic vertebral artery dissection, or entrapment of the basilar artery into the clivus fracture. To date, however, there are no reports of traumatic basilar artery entrapment without a clivus fracture. Here, we report the first case of traumatic basilar artery occlusion caused by entrapment into an originally existing bone defect. A 67-year-old man with a history of treatment for intracranial aneurysm suffered multiple traumatic injuries in a fall. On arrival at our hospital, he presented with neurogenic shock with quadriplegia. Computed tomography (CT) showed small epidural hematoma, C4-6 cervical spinous process fracture, and Th2-3 vertebral body fracture. CT angiography revealed occlusion of the basilar artery trunk. As vertebrobasilar artery dissections and clivus fracture were not observed; however, we could not elucidate the pathology of the basilar artery occlusion. On day 4, after surgery for the cervical and thoracic lesions, he exhibited consciousness disturbance. Diffusion-weighted imaging on day 5 showed hyperintensities in the brainstem and cerebellum. Basi-parallel anatomic scanning magnetic resonance imaging showed that the basilar artery, while lacking vascular wall injuries, was tethered into the clivus. Antithrombotic therapy was performed, but the patient progressed to a locked-in state. Previous head CT before the trauma revealed a bone defect already present in the clivus. We speculated basilar artery entrapment into this preexisting bone defect. We must look for basilar artery injury in trauma patients even in the absence of clivus fracture.

Clinical utility of 18 F-fluorodeoxyglucose/positron emission tomography in diagnosis of immunoglobulin G4-related sclerosing sialadenitis.

OBJECTIVES/HYPOTHESIS: The aim of this study was to evaluate the utility of 18 F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for accurately diagnosing immunoglobulin G4-related sclerosing sialadenitis (IgG4-SS). STUDY DESIGN: Retrospective cohort study. METHODS: We reviewed the records of 64 patients with IgG4-SS (35 male and 29 female patients) and 10 patients with clinically suspected IgG4-SS. Pathological diagnoses of patients clinically suspected with IgG4-SS included four cases of malignant lymphoma, one case of multicentric Castleman disease, one case of Sjögren's syndrome, and four cases of sialadenitis. All patients underwent submandibular gland (SMG) biopsies and baseline FDG-PET/CT evaluation. Clinical, serological, pathological, and PET/CT findings were analyzed. We also investigated maximum standardized uptake values (SUVmax) in the salivary glands of 15 patients with malignant disease of the salivary glands during the same period. RESULTS: Increased FDG uptake in the SMG and parotid gland was found in 63 (98%) and 23 (35%) patients with IgG4-SS, respectively. FDG uptake of the bilateral SMG and unilateral SMG was recorded in 57 patients (89%) and six patients (9%), respectively. Mean SUVmax in patients with malignant disease of the salivary glands was significantly higher than that in patients with IgG4-SS (P = .035). We defined a positive test for IgG4-SS diagnosis as high SMG FDG uptake and serum IgG4 level ≥135 mg/dL, resulting in a sensitivity, specificity, and accuracy of 96.9%, 90.0%, and 86.4%, respectively. CONCLUSIONS: FDG-PET/CT findings in combination with serological and clinical findings may have the capacity to diagnose IgG4-SS and lead to less-invasive biopsy procedures. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:1120-1125, 2018.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (J-SSCG 2016)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2016 (JSSCG 2016), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in February 2017 in Japanese. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. Members of the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine were selected and organized into 19 committee members and 52 working group members. The guidelines were prepared in accordance with the Medical Information Network Distribution Service (Minds) creation procedures. The Academic Guidelines Promotion Team was organized to oversee and provide academic support to the respective activities allocated to each Guideline Creation Team. To improve quality assurance and workflow transparency, a mutual peer review system was established, and discussions within eachteam were open to the public. Public comments were collected once after the initial formulation of a clinical question (CQ), and twice during the review of the final draft. Recommendations were determined to have been adopted after obtaining support from a twothirds (>66.6%) majority vote of each of the 19 committee members. A total of 87 CQs were selected among 19 clinical areas, including pediatric topics and several other important areas not covered in the first edition of the Japanese guidelines (J-SSCG 2012). The approval rate obtained through committee voting, in additionto ratings of the strengths of the recommendation and its supporting evidence were also added to each recommendation statement.We conducted meta-analyses for 29 CQs. Thirty seven CQs contained recommendations in the form of an expert consensus due to insufficient evidence. No recommendations were provided for 5 CQs.Based on the evidence gathered, we were able to formulate Japanese-specific clinical practice guidelines that are tailored to the Japanese context in a highly transparent manner. These guidelines can easily be used not only by specialists, but also by non-specialists, general clinicians, nurses, pharmacists, clinical engineers, and other healthcare professionals.

Three cases of implantation of a SureScan® system and MRI for investigating causes of pain.

We report three cases of implantation of the SureScan® system and magnetic resonance imaging (MRI) for investigating causes of pain. Although there were metal-induced artifacts on the MR images of 2 patients, the artifacts did not affect the images of structures that needed to be assessed to make the diagnosis. The SureScan® system enabled patients implanted with spinal cord stimulation devices to undergo MRI.

Cerebral air embolism associated with penetrating lung injury: a case report and review of the literature.

CASE: A 44-year-old man intentionally stabbed himself in the anterior neck and left thorax with a fruit knife. Physical examination revealed two open wounds entering the thoracic cavity in the front chest, and a stab wound entering the trachea at the neck. Two chest tubes were initially inserted for the left lung injury with open hemopneumothorax. Nevertheless, the worsening oxygenation required positive pressure ventilation (PPV) with endotracheal intubation. OUTCOME: Right hemiparesis was found during weaning from PPV. Magnetic resonance imaging revealed multiple infarctions in the area of the bifrontal and right temporal lobes. Cerebral air embolism (CAE) was strongly suspected from the imaging findings and clinical course. CONCLUSION: We concluded that mechanical ventilation was strongly involved in the occurrence of CAE. If delayed abnormal neurological findings are observed in patients with penetrating lung injuries receiving PPV management, CAE should be considered.

Improvement in automated quantitation of myocardial perfusion abnormality by using iterative reconstruction image in combination with resolution recovery, attenuation and scatter corrections for the detection of coronary artery disease.

OBJECTIVE: An iterative reconstruction method in combination with resolution recovery, attenuation and scatter corrections (IR-RASC) can improve image quality. It, however, is undetermined whether this technique can improve the detection of coronary artery disease (CAD) when automated quantitative analysis is used. This study evaluated diagnostic values of IR-RASC in combination with automated quantitative analysis in stress myocardial perfusion imaging (MPI) in the CAD detection. METHODS: This study enrolled consecutive 64 patients (mean age 66.2 ± 17.3 years, 39 males) who had undergone both 99mTc-labeled tetrofosmin stress MPI and coronary angiography within 3 months. Stress MPI abnormalities quantified as summed stress score (SSS), summed rest score (SRS) and summed difference score (SDS) by Heart Risk View-S (HRV-S) and Quantitative Perfusion SPECT (QPS) softwares using IR-RASC images were compared with those by using conventional filtered back-projection method (FBP) images and angiographic findings. RESULTS: Based on expert visual assessment, SSS and SRS by HRV-S/QPS softwares with IR-RASC were significantly lower than those by HRV-S/QPS softwares with FBP at mid- and basal left ventricular segments. Receiver-operating characteristics analysis showed that areas under the curve assessed by HRV-S (0.687) and QPS (0.678) with IR-RASC were nearly identical to those (0.717-0.724) by expert assessment with FBP, and were significantly (P < 0.05) greater than those by HRV-S (0.505) and QPS (0.522) with FBP. When HRV-S was used, the specificity and diagnostic accuracy of IR-RASC in the CAD detection were significantly greater than those of FBP: 90.3 versus 51.6%, P < 0.0001 and 79.7 versus 54.7%, P = 0.0027, respectively. Likewise, when QPS was used, the specificity and diagnostic accuracy of IR-RASC in the CAD detection were significantly greater than those of FBP: 80.6 versus 41.9%, P < 0.0001, and 78.1 versus 51.6%, P = 0.0018, respectively. There, however, were no significant differences in sensitivity between IR-RASC and FBP images. CONCLUSIONS: IR-RASC can improve diagnostic accuracy of the CAD detection using an automated scoring system compared to FBP, by reducing false positivity due to artefactual appearance.