Radiation dose from computed tomography in patients with necrotizing pancreatitis: how much is too much?

Current trends in acute pancreatitis: Diagnostic and therapeutic challenges

Acute pancreatitis (AP) is an inflammatory disease of the pancreas, which can progress to severe AP, with a high risk of death. It is one of the most complicated and clinically challenging of all disorders affecting the abdomen. The main causes of AP are gallstone migration and alcohol abuse. Other causes are uncommon, controversial and insufficiently explained. The disease is primarily characterized by inappropriate activation of trypsinogen, infiltration of inflammatory cells, and destruction of secretory cells. According to the revised Atlanta classification, severity of the disease is categorized into three levels: Mild, moderately severe and severe, depending upon organ failure and local as well as systemic complications. Various methods have been used for predicting the severity of AP and its outcome, such as clinical evaluation, imaging evaluation and testing of various biochemical markers. However, AP is a very complex disease and despite the fact that there are of several clinical, biochemical and imaging criteria for assessment of severity of AP, it is not an easy task to predict its subsequent course. Therefore, there are existing controversies regarding diagnostic and therapeutic modalities, their effectiveness and complications in the treatment of AP. The main reason being the fact, that the pathophysiologic mechanisms of AP have not been fully elucidated and need to be studied further. In this editorial article, we discuss the efficacy of the existing diagnostic and therapeutic modalities, complications and treatment failure in the management of AP.

Prognostic factors associated with development of infected necrosis in patients with acute necrotizing or severe pancreatitis-A systematic review and meta-analysis

PURPOSE

Acute pancreatitis is a potentially life-threatening condition with a wide spectrum of clinical presentation and illness severity. An infection of pancreatic necrosis (IPN) results in a more than twofold increase in mortality risk as compared with patients with sterile necrosis. We sought to identify prognostic factors for the development of IPN among adult patients with severe or necrotizing pancreatitis.

METHODS

We conducted this prognostic review in accordance with systematic review methodology guidelines. We searched six databases from inception through March 21, 2021. We included English language studies describing prognostic factors associated with the development of IPN. We pooled unadjusted odds ratio (uOR) and adjusted odds ratios (aOR) for prognostic factors using a random-effects model. We assessed risk of bias using the Quality in Prognosis Studies tool and certainty of evidence using the GRADE approach.

RESULTS

We included 31 observational studies involving 5,210 patients. Factors with moderate or higher certainty of association with increased IPN risk include older age (uOR, 2.19; 95% confidence interval [CI], 1.39-3.45, moderate certainty), gallstone etiology (aOR, 2.35; 95% CI, 1.36-4.04, high certainty), greater than 50% necrosis of the pancreas (aOR, 3.61; 95% CI, 2.15-6.04, high certainty), delayed enteral nutrition (aOR, 2.09; 95% CI, 1.26-3.47, moderate certainty), multiple or persistent organ failure (aOR, 11.71; 95% CI, 4.97-27.56, high certainty), and invasive mechanical ventilation (uOR, 12.24; 95% CI, 2.28-65.67, high certainty).

CONCLUSION

This meta-analysis confirms the association between several clinical early prognostic factors and the risk of IPN development among patients with severe or necrotizing pancreatitis. These findings provide the foundation for the development of an IPN risk stratification tool to guide more targeted clinical trials for prevention or early intervention strategies.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, Level IV.

Burden of Ionizing Radiation in the Diagnosis and Management of Necrotizing Pancreatitis

INTRODUCTION

A step-up endoscopic or percutaneous approach improves outcomes in necrotizing pancreatitis (NP). However, these require multiple radiographic studies and fluoroscopic procedures, which use low-dose ionizing radiation. The cumulative radiation exposure for treatment of NP has not been well defined.

METHODS

We conducted a retrospective study of consecutive patients with NP admitted to University of California San Francisco Medical Center from January 2011 to June 2019. We calculated effective doses for fluoroscopic procedures using the dose area product and used the National Cancer Institute tool for computed tomography studies. The primary outcome was the cumulative effective dose (CED). Multivariable logistic regression was used to evaluate risk factors of high exposure (CED > 500 mSv).

RESULTS

One hundred seventy-one patients with NP (mean follow-up 40 ± 18 months) underwent a median of 7 (interquartile range [IQR] 5-11) computed tomography scans and 7 (IQR 5-12) fluoroscopic procedures. The median CED was 274 mSv (IQR 177-245) and 30% (51) of patients received high exposure. Risk factors of high exposure include multiorgan failure (aOR 3.47, 95%-CI: 1.53-9.88, P = 0.003), infected necrosis (adjusted odds ratio [aOR] 3.89 95%-CI:1.53-9.88, P = 0.005), and step-up endoscopic approach (aOR 1.86, 95%-CI: 1.41-1.84, P = 0.001) when compared with step-up percutaneous approach.

DISCUSSION

Patients with NP were exposed to a substantial amount of ionizing radiation (257 mSv) as a part of their treatment, and 30% received more than 500 mSv, which corresponds with a 5% increase in lifetime cancer risk. Severity of NP and a step-up endoscopic approach were associated with CED > 500 mSv. Further studies are needed to help develop low-radiation treatment protocols for NP, particularly in patients receiving endoscopic therapy.

Prospective Analysis of the Mechanisms Underlying Ineffective Deep Vein Thrombosis Prophylaxis in Necrotizing Pancreatitis

BACKGROUND

Patients with necrotizing pancreatitis (NP) have the highest rate of venous thromboembolism (VTE) of any hospitalized patient (57%). We hypothesized that VTE prophylaxis might be inadequate in the setting of this profound inflammatory disease and that early detection of deep vein thrombosis would limit pulmonary embolism.

STUDY DESIGN

All patients with NP treated at a single center between August 2018 and December 2019 were enrolled in prospective, weekly VTE screening, including 4-extremity duplex ultrasound. Routine chemoprophylaxis included low-molecular-weight or unfractionated heparin. Peak serum anti-factor Xa concentration was measured during weekly screening (goal prophylaxis 0.2 to 0.4 IU/mL).

RESULTS

Eighty-five patients with NP underwent a total of 201 screening events (mean 2.4 per patient). VTE developed in 55 patients (65%), including splanchnic vein thrombosis in 41 patients (48%) and extremity deep vein thrombosis (eDVT) in 32 patients (38%). Extremity DVT was diagnosed a mean ± SD of 44 ± 30 days after NP onset. Symptomatic pulmonary embolism was prevented in all patients diagnosed with eDVT and no contraindication to anticoagulation (0 of 29). Prophylactic anti-factor Xa concentration was only achieved in 21% (12 of 57 screening events); no eDVTs developed in patients achieving prophylactic anti-factor Xa concentration.

CONCLUSIONS

In patients with NP, identification of eDVT by screening ultrasound permits early treatment and prevents symptomatic pulmonary embolism. Fixed dosing of chemical prophylaxis is inadequate in most patients with NP and likely contributes to the mechanism of increased VTE in NP.

Visceral artery pseudoaneurysm in necrotizing pancreatitis: incidence and outcomes

Background

Visceral artery pseudoaneurysms (VA-PSA) occur in necrotizing pancreatitis; however, little is known about their natural history. This study sought to evaluate the incidence and outcomes of VA-PSA in a large cohort of patients with necrotizing pancreatitis.

Methods

Data for patients with necrotizing pancreatitis who were treated between 2005 and 2017 at Indiana University Health University Hospital and who developed a VA-PSA were reviewed to assess incidence, presentation, treatment and outcomes.

Results

Twenty-eight of 647 patients with necrotizing pancreatitis (4.3%) developed a VA-PSA between 2005 and 2017. The artery most commonly involved was the splenic artery (36%), followed by the gastroduodenal artery (24%). The most common presenting symptom was bloody drain output (32%), followed by incidental computed tomographic findings (21%). The median time from onset of necrotizing pancreatitis to diagnosis of a VA-PSA was 63.5 days (range 1-957 d). Twenty-five of the 28 patients who developed VA-PSA (89%) were successfully treated with percutaneous angioembolization. Three patients (11%) required surgery: 1 patient rebled following embolization and required operative management, and 2 underwent upfront operative management. The mortality rate attributable to hemorrhage from a VA-PSA in the setting of necrotizing pancreatitis was 14% (4 of 28 patients).

Conclusion

In this study, VA-PSA occurred in 4.3% of patients with necrotizing pancreatitis. Percutaneous angioembolization effectively treated most cases; however, mortality from VA-PSA was high (14%). A high degree of clinical suspicion remains critical for early diagnosis of this potentially fatal problem.

Surgical Transgastric Necrosectomy for Necrotizing Pancreatitis: A Single-stage Procedure for Walled-off Pancreatic Necrosis

OBJECTIVE

The aim of this study was to evaluate the role of surgical transgastric necrosectomy (TGN) for walled-off pancreatic necrosis (WON) in selected patients.

BACKGROUND

WON is a common consequence of severe pancreatitis and typically occurs 3 to 5 weeks after the onset of acute pancreatitis. When symptomatic, it can require intervention.

METHODS

A retrospective review of patients with WON undergoing surgical management at 3 high-volume pancreatic institutions was performed. Surgical indications, intervention timing, technical methodology, and patient outcomes were evaluated. Patients undergoing intervention <30 days were excluded. Differences across centers were evaluated using a P value of <0.05 as significant.

RESULTS

One hundred seventy-eight total patients were analyzed (mean WON diameter = 14 cm, 64% male, mean age = 51 years) across 3 centers. The majority required inpatient admission with a median preoperative length of hospital stay of 29 days (25% required preoperative critical care support). Most (96%) patients underwent a TGN. The median duration of time between the onset of pancreatitis symptoms and operative intervention was 60 days. Thirty-nine percent of the necrosum was infected. Postoperative morbidity and mortality were 38% and 2%, respectively. The median postoperative length of hospital length of stay was 8 days, with the majority of patients discharged home. The median length of follow-up was 21 months, with 91% of patients having complete clinical resolution of symptoms at a median of 6 weeks. Readmission to hospital and/or a repeat intervention was also not infrequent (20%).

CONCLUSION

Surgical TGN is an excellent 1-stage surgical option for symptomatic WON in a highly selected group of patients. Precise surgical technique and long-term outpatient follow-up are mandatory for optimal patient outcomes.

Radiation dose from computed tomography in patients with acute pancreatitis: an audit from a tertiary care referral hospital

BACKGROUND

There is a limited data on the radiation dose from computed tomography (CT) in patients with acute pancreatitis (AP). The present study evaluated the radiation dose from CT scans in patients with AP.

MATERIAL

A retrospective review of CT reports of patients with AP was conducted. The type of CT scan (non-contrast vs. single-phase vs. biphasic CT) was recorded. The mean number of CT scans and cumulative radiation dose was calculated. The indications and abnormalities on biphasic CT scans were recorded. The radiation doses between different types of the scan were compared.

RESULTS

495 CT studies in 351 patients were evaluated. In patients (n = 78, 22.2%) undergoing multiple CT scans, mean number of CT scans per patient and mean radiation dose were 2.64 ± 1.18 (range 2-9) and 24 ± 15 mSv (range 8.3-79.8 mSv), respectively. The mean radiation dose was significantly greater in patients with modified CT severity index ≥ 8 (n = 63) [25.08 mSv vs. 18.96 mSv, (P = 0.048)]. 61 (12.32%) biphasic scans were performed. A definite indication for a biphasic CT scan was identified in 20 (32.7%) patients. Arterial abnormalities were detected in 6 (9.8%) patients undergoing CT for defined indication. Mean radiation dose in this group was 13.26 ± 7.64 mSv (range 3.42-38.27 mSv) which was significantly greater than the single venous phase scan (7.96 ± 3.48 mSv, P < 0.001).

CONCLUSION

There is a potential for substantial radiation exposure from CT scans to patients with AP. Patients with severe AP and those undergoing biphasic scans have significantly higher radiation exposure. Hence, routine arterial phase acquisition should be avoided.

Imaging guidelines for acute pancreatitis: when and when not to image

In patients with acute pancreatitis (AP), diagnostic imaging is performed for various reasons, including the detection of the etiology (e.g., biliary obstruction caused by gallstones), diagnosis of pancreatitis in an unclear clinical setting, assessment of the severity of the process, and evaluation of its complications. In spite of the potential benefits of these imaging studies in the setting of AP, especially economic consequences but also medical risks are associated with diagnostic imaging, including increase of the effective radiation dose received by patients with AP and rising health care costs, frequently without impact on management. The rising incidence of acute pancreatitis in the Western world is escalating its financial burden with national health care expenses of over 2.5 billion dollars annually. Despite evidence-based national recommendations on utilization of diagnostic imaging in patients with AP, unnecessary imaging studies are still frequently performed, especially in the early hospital course. The purpose of this article is, therefore, to review the imaging guidelines for acute pancreatitis with regards to when and when not to image, with the aim to minimize inappropriate utilization.

2019 WSES guidelines for the management of severe acute pancreatitis

Although most patients with acute pancreatitis have the mild form of the disease, about 20-30% develops a severe form, often associated with single or multiple organ dysfunction requiring intensive care. Identifying the severe form early is one of the major challenges in managing severe acute pancreatitis. Infection of the pancreatic and peripancreatic necrosis occurs in about 20-40% of patients with severe acute pancreatitis, and is associated with worsening organ dysfunctions. While most patients with sterile necrosis can be managed nonoperatively, patients with infected necrosis usually require an intervention that can be percutaneous, endoscopic, or open surgical. These guidelines present evidence-based international consensus statements on the management of severe acute pancreatitis from collaboration of a panel of experts meeting during the World Congress of Emergency Surgery in June 27-30, 2018 in Bertinoro, Italy. The main topics of these guidelines fall under the following topics: Diagnosis, Antibiotic treatment, Management in the Intensive Care Unit, Surgical and operative management, and Open abdomen.

Persistent SIRS and acute fluid collections are associated with increased CT scanning in acute interstitial pancreatitis

BACKGROUND

The use of computed tomography (CT) in acute pancreatitis (AP) continues to increase in parallel with the increasing use of diagnostic imaging in clinical medicine.

AIM

To determine the factors associated with obtaining >1 CT scan in acute interstitial pancreatitis (AIP).

METHODS

Demographic and clinical data of all adult patients admitted between 1/2010 and 1/2015 with AP (AP) were evaluated. Only patients with a CT severity index (CTSI) ≤ 3 on a CT obtained within 48 h of presentation were included.

RESULTS

A total of 229 patients were included, of whom 206 (90%) had a single CT and 23 (10%) had >1 CT during the first week of hospitalization. Patients undergoing >1 CT had significantly higher rates of acute fluid collection (AFC), persistent SIRS, opioid use ≥4 days, and persistent organ failure compared to those undergoing 1 CT (p < .05 for all). On multivariable analysis, only persistent SIRS (OR = 3.6, 95% CI 1.4-9.6, p = .01) and an AFC on initial CT (OR = 3.5, 95% CI 1.4-9, p = .009) were independently associated with obtaining >1 CT.

CONCLUSION

An AFC on initial CT and persistent SIRS are associated with increased CT imaging in AIP patients. However, these additional CT scans did not change clinical management.

Temporal trends in the use of diagnostic imaging for inpatients with pancreatic conditions: How much ionizing radiation are we using?

BACKGROUND

Low-dose ionizing radiation from medical imaging has been indirectly linked with subsequent cancer and increased costs. Computed tomography (CT) is the gold standard for defining pancreatic anatomy and complications. Our primary goal was to identify the temporal trends associated with diagnostic imaging for inpatients with pancreatic diseases.

METHODS

Data were extracted from the Healthcare Cost and Utilization Project Nationwide Inpatient Sample (NIS) database from 2000 to 2008. Pancreas-related ICD-9 diagnostic codes were matched to all relevant imaging modalities.

RESULTS

Between 2000 and 2008, a significant increase in admissions (p < 0.001), but decrease in overall imaging procedures (p = 0.032), for all pancreatic disorders was observed. This was primarily a result of a reduction in the number of CT and endoscopic retrograde cholangiopancreatography examinations (i.e., reduced radiation exposure, p = 0.008). A concurrent increase in the number of inpatient magnetic resonance cholangiopancreatography/magnetic resonance imaging performed was observed (p = 0.040). Intraoperative cholangiography and CT remained the dominant imaging modality of choice overall (p = 0.027).

CONCLUSION

Inpatients with pancreatic diseases often require diagnostic imaging during their stay. This results in substantial exposure to ionizing radiation. The observed decrease in the use of CT may reflect an improved awareness of potential stochastic risks.

Treating acute pancreatitis: what's new?

The medical treatment of acute pancreatitis continues to focus on supportive care, including fluid therapy, nutrition, and antibiotics, all of which will be critically reviewed. Pharmacologic agents that were previously studied were found to be ineffective likely due to a combination of their targets and flaws in trial design. Potential future pharmacologic agents, particularly those that target intracellular calcium signaling, as well as considerations for trial design will be discussed. As the incidence of acute pancreatitis continues to increase, greater efforts will be needed to prevent hospitalization, readmission and excessive imaging in order to reduce overall healthcare costs. Primary prevention continues to focus on post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis and secondary prevention on cholecystectomy for biliary pancreatitis as well as alcohol and smoking abstinence.

Minimally invasive treatment of pancreatic pseudocysts

A pancreatic pseudocyst (PPC) is typically a complication of acute and chronic pancreatitis, trauma or pancreatic duct obstruction. The diagnosis of PPC can be made if an acute fluid collection persists for 4 to 6 wk and is enveloped by a distinct wall. Most PPCs regress spontaneously and require no treatment, whereas some may persist and progress until complications occur. The decision whether to treat a patient who has a PPC, as well as when and with what treatment modalities, is a difficult one. PPCs can be treated with a variety of methods: percutaneous catheter drainage (PCD), endoscopic transpapillary or transmural drainage, laparoscopic surgery, or open pseudocystoenterostomy. The recent trend in the management of symptomatic PPC has moved toward less invasive approaches such as endoscopic- and image-guided PCD. The endoscopic approach is suitable because most PPCs lie adjacent to the stomach. The major advantage of the endoscopic approach is that it creates a permanent pseudocysto-gastric track with no spillage of pancreatic enzymes. However, given the drainage problems, the monitoring, catheter manipulation and the analysis of cystic content are very difficult or impossible to perform endoscopically, unlike in the PCD approach. Several conditions must be met to achieve the complete obliteration of the cyst cavity. Pancreatic duct anatomy is an important factor in the prognosis of the treatment outcome, and the recovery of disrupted pancreatic ducts is the main prognostic factor for successful treatment of PPC, regardless of the treatment method used. In this article, we review and evaluate the minimally invasive approaches in the management of PPCs.

Combined Use of Automatic Tube Voltage Selection and Current Modulation with Iterative Reconstruction for CT Evaluation of Small Hypervascular Hepatocellular Carcinomas: Effect on Lesion Conspicuity and Image Quality

Objective

To assess the lesion conspicuity and image quality in CT evaluation of small (≤ 3 cm) hepatocellular carcinomas (HCCs) using automatic tube voltage selection (ATVS) and automatic tube current modulation (ATCM) with or without iterative reconstruction.

Materials and Methods

One hundred and five patients with 123 HCC lesions were included. Fifty-seven patients were scanned using both ATVS and ATCM and images were reconstructed using either filtered back-projection (FBP) (group A1) or sinogram-affirmed iterative reconstruction (SAFIRE) (group A2). Forty-eight patients were imaged using only ATCM, with a fixed tube potential of 120 kVp and FBP reconstruction (group B). Quantitative parameters (image noise in Hounsfield unit and contrast-to-noise ratio of the aorta, the liver, and the hepatic tumors) and qualitative visual parameters (image noise, overall image quality, and lesion conspicuity as graded on a 5-point scale) were compared among the groups.

Results

Group A2 scanned with the automatically chosen 80 kVp and 100 kVp tube voltages ranked the best in lesion conspicuity and subjective and objective image quality (p values ranging from < 0.001 to 0.004) among the three groups, except for overall image quality between group A2 and group B (p = 0.022). Group A1 showed higher image noise (p = 0.005) but similar lesion conspicuity and overall image quality as compared with group B. The radiation dose in group A was 19% lower than that in group B (p = 0.022).

Conclusion

CT scanning with combined use of ATVS and ATCM and image reconstruction with SAFIRE algorithm provides higher lesion conspicuity and better image quality for evaluating small hepatic HCCs with radiation dose reduction.

Treatment of severe acute pancreatitis and its complications

Severe acute pancreatitis (SAP), which is the most serious type of this disorder, is associated with high morbidity and mortality. SAP runs a biphasic course. During the first 1-2 wk, a pro-inflammatory response results in systemic inflammatory response syndrome (SIRS). If the SIRS is severe, it can lead to early multisystem organ failure (MOF). After the first 1-2 wk, a transition from a pro-inflammatory response to an anti-inflammatory response occurs; during this transition, the patient is at risk for intestinal flora translocation and the development of secondary infection of the necrotic tissue, which can result in sepsis and late MOF. Many recommendations have been made regarding SAP management and its complications. However, despite the reduction in overall mortality in the last decade, SAP is still associated with high mortality. In the majority of cases, sterile necrosis should be managed conservatively, whereas in infected necrotizing pancreatitis, the infected non-vital solid tissue should be removed to control the sepsis. Intervention should be delayed for as long as possible to allow better demarcation and liquefaction of the necrosis. Currently, the step-up approach (delay, drain, and debride) may be considered as the reference standard intervention for this disorder.

The impact of an acute care surgery clinical care pathway for suspected appendicitis on the use of CT in the emergency department

BACKGROUND

The natural evolution of an acute care surgery (ACS) service is to develop disease-specific care pathways aimed at quality improvement. Our primary goal was to evaluate the implementation of an ACS pathway dedicated to suspected appendicitis on patient flow and the use of computed tomography (CT) in the emergency department (ED).

METHODS

All adults within a large health care system (3 hospitals) with suspected appendicitis were analyzed during our study period, which included 3 time periods: pre- and postimplementation of the disease-specific pathway and at 12-month follow-up.

RESULTS

Of the 1168 consultations for appendicitis that took place during our study period, 349 occurred preimplementation, 392 occurred postimplementation, and 427 were follow-up visits. In all, 877 (75%) patients were admitted to the ACS service. Overall, 83% of patients underwent surgery within 6 hours. The mean wait time from CT request to obtaining the CT scan decreased with pathway implementation at all sites (197 v. 143 min, p < 0.001). This improvement was sustained at 12-month followup (131 min, p < 0.001). The pathway increased the number of CTs completed in under 2 hours from 3% to 42% (p < 0.001). No decrease in the total number of CTs or the pattern of ultrasonography was noted (p = 0.42). Wait times from ED triage to surgery were shortened (665 min preimplementation, 633 min postimplementation, 631 min at the 12-month follow-up, p = 0.040).

CONCLUSION

A clinical care pathway dedicated to suspected appendicitis can decrease times to both CT scan and surgical intervention.

Optimization of computed tomography (CT) arthrography of hip for the visualization of cartilage: an in vitro study

OBJECTIVE

We sought to optimize the kilovoltage, tube current, and the radiation dose of computed tomographic arthrography of the hip joint using in vitro methods.

MATERIALS AND METHODS

A phantom was prepared using a left femoral head harvested from a patient undergoing total hip arthroplasty and packed in a condom filled with iodinated contrast. The right hip joint of a cadaver was also injected with iodinated contrast. The phantom and the cadaver were scanned using different values of peak kilovoltage (kVp) and tube current (milliamp seconds, mAs). Three different regions of interest (ROI) were drawn in the cartilage, subchondral bone plate, and intraarticular contrast. The attenuation values, contrast/noise ratio (CNR), and effective dose were calculated. Two independent observers classified the quality of the contrast-cartilage interface and the cartilage-subchondral bone plate interface as (1) diagnostic quality or (2) nondiagnostic quality.

RESULTS

Contrast, cartilage, and subchondral bone plate attenuation values decreased at higher kVp. CNR increased with both kVp and mAs. The qualitative analysis showed that in both phantom and cadaver, at 120 kVp and 50 mAs, the contrast-cartilage and cartilage-subchondral bone plate interfaces were of diagnostic quality, with an effective dose decreased to 0.5 MSv.

CONCLUSIONS

The absolute effective dose is not directly related to the quality of images but to the specific combination of kVp and mAs used for image acquisition. The combination of 120 kVp and 50 mAs can be suggested to decrease the dose without adversely affect the visibility of cartilage and subchondral bone plate.

Low-dose ionising radiation from medical imaging in patients hospitalised in Internal Medicine

BACKGROUND

Medical imaging is responsible for increasing exposure to low-dose ionising radiation in the general population. The extent of exposure in specific patient populations remains to be determined.

AIM

We sought to determine the level of exposure in patients hospitalised in General Internal Medicine.

METHODS

In this retrospective cohort study, we searched the Centre Informatisé de Recherche Évaluative en Services et Soins de Santé database for adult patients hospitalised in General Internal Medicine from 1 January 2008 to 31 December 2008. We collected data on demographics, co-morbidities, and radiological and nuclear imaging. We used data from the literature to calculate an estimated annual effective dose for each patient and searched for factors associated with higher exposure.

RESULTS

One thousand one hundred eighty-seven (1187) patients were hospitalised at least once during the study period. The median age was 69 years (interquartile range 56-81) and 636 (53.6%) were men. The median annual effective dose of the whole cohort was 8.7 mSv/year. Patients aged between 55 and 80 years were exposed to a higher median effective dose compared with their younger and older counterparts (P < 0.001). Patients with cardiac, pulmonary, peripheral arterial and neoplastic disease were at higher risk of exposure to high and very high annual effective dose (P < 0.01). Patients with longer hospitalisations were at higher risk of exposure to high and very high annual effective dose (P < 0.01).

CONCLUSION

Patients hospitalised on a General Internal Medicine ward are exposed to three times more ionising radiation than the general population.

Acute care surgery: the impact of an acute care surgery service on assessment, flow, and disposition in the emergency department

BACKGROUND

Acute care surgery (ACS) services are becoming increasingly popular.

METHODS

Assessment, flow, and disposition of adult ACS patients (acute, nontrauma surgical conditions) through the emergency department (ED) in a large health care system (Calgary) were prospectively analyzed.

RESULTS

Among 447 ACS ED consultations over 3 centers (70% admitted to ACS), the median wait time from the consultation request to ACS arrival was 36 minutes, and from ACS arrival to the admission request it was 91 minutes. The total ACS-dependent time was 127 minutes compared with 261 minutes for initial ED activities and 104 minutes for transfer to a hospital ward (P < .05). Forty percent of patients underwent computed tomography (CT) imaging (76% before consultation). The time to ACS consultation was 305 minutes when a CT scan was performed first.

CONCLUSIONS

An ACS service results in rapid ED assessment of surgical emergencies. Patient waiting is dominated by the time before requesting ACS consultation and/or waiting for transfer to the ward.

Can cervical spine computed tomography assist in detecting occult pneumothoraces?

INTRODUCTION

Screening CT often detects posttraumatic pneumothoraces that were not diagnosed on a preceding supine anteroposterior chest radiograph (occult pneumothoraces (OPTXs)). Because abdominal CT imaging misses OPTXs in the upper thorax, the objective of this study was to evaluate the utility of cervical spine (C-spine) CT screening for diagnosing OPTXs.

METHODS

A dual-institution (Foothills Medical Centre and Grady Memorial Hospital) retrospective review of consecutive OPTXs was performed. The accuracy of various CT screening protocols in detecting OPTXs was compared.

RESULTS

OPTXs were detected in 75 patients. Patient demographics and injury characteristics were similar between centres (65% male; 97% blunt mechanism; 29% hemodynamically unstable; mean ISS=27; mean length of stay=22 days; mortality=9%)(p>0.05). Patients received either abdominal (41%) or thoraco-abdominal (59%) CT imaging. Most patients (89%) also underwent C-spine CT imaging. OPTXs were evident on thoracic CT in 100% (44/44), abdominal CT in 83% (62/75), and C-spine CT in 82% (55/67) of cases. All patients with OPTXs identified solely on thoracic CT (i.e. not abdominal) who also underwent imaging of their C-spine could have had their OTPXs diagnosed by using the pulmonary windows setting of their C-spine CT series. Combining C-spine and abdominal CT screening diagnosed all OPTXs (67/67) detected on thoracic CT, for patients who also underwent these investigations.

CONCLUSIONS

OPTXs were evident on thoracic (and not abdominal) CT in 17% of severely injured patients. For patients who also underwent C-spine imaging, all OPTXs isolated to thoracic CT could be diagnosed by using the pulmonary windows setting of their C-spine CT imaging protocol. All OPTXs, regardless of intra-thoracic location, could also be detected by combining C-spine and abdominal CT screening.

Quality initiatives: CT radiation dose reduction: how to implement change without sacrificing diagnostic quality

The risks and benefits of using computed tomography (CT) as opposed to another imaging modality to accomplish a particular clinical goal should be weighed carefully. To accurately assess radiation risks and keep radiation doses as low as reasonably achievable, radiologists must be knowledgeable about the doses delivered during various types of CT studies performed at their institutions. The authors of this article propose a process improvement approach that includes the estimation of effective radiation dose levels, formulation of dose reduction goals, modification of acquisition protocols, assessment of effects on image quality, and implementation of changes necessary to ensure quality. A first step toward developing informed radiation dose reduction goals is to become familiar with the radiation dose values and radiation-associated health risks reported in the literature. Next, to determine the baseline dose values for a CT study at a particular institution, dose data can be collected from the CT scanners, interpreted, tabulated, and graphed. CT protocols can be modified to reduce overall effective dose by using techniques such as automated exposure control and iterative reconstruction, as well as by decreasing the number of scanning phases, increasing the section thickness, and adjusting the peak voltage (kVp setting), tube current-time product (milliampere-seconds), and pitch. Last, PDSA (plan, do, study, act) cycles can be established to detect and minimize negative effects of dose reduction methods on image quality.