Low-dose computed tomography versus plain abdominal radiography in the investigation of an acute abdomen

Current abdominal X-rays practice in accident and emergency

INTRODUCTION

Previous literature reviews revealed that abdominal X-rays (AXR) performed for the accident and emergency department (A&E), had low sensitivity, high further imaging and non-alignment rate to the Royal College of Radiologists (RCR) guidelines. A study was performed to investigate the current practice with the aim of making recommendations to improve practice, which can reduce patients' radiation exposures, while can re-routing resources to other priorities.

METHODS

A study was performed in one of the UK's largest A&Es, in accordance with the RCR guidelines. All the AXR requests from A&E, regardless of the patient's age, within a 28-day period, were retrospectively assessed. Non-A&E patients and abandoned examinations due to uncooperative patients were excluded. The total number of AXR requests received by the A&E imaging department was 169, with 28/169 falling into the exclusion criteria.

RESULTS

Of the 141 included requests, five unjustified requests were correctly rejected. The remaining 136 requests were accepted and performed, though only 115/136 (84.6%) of these were justified. The most common justified and unjustified indications were obstruction and renal stones, respectively. Only 4% of reported AXR had pathological abnormalities, while 45/136 patients had further imaging.

CONCLUSIONS

The small proportion of significant findings echoed previous studies, suggesting an AXR overuse. Over 80% of non-compliant requests were performed, and awareness of the justification guidelines can be increased by clinical governance, posters, or an algorithm previously presented. The 32.4% further imaging rate recorded in this study, as opposed to the 73.7% reported in previous literature, merits attention.

IMPLICATIONS TO PRACTICE

Stopping the overuse of AXR can minimise the radiation dose received and relieve the mounting pressure in imaging and reporting, which can serve other patients who would benefit from the services otherwise.

The utility of the abdominal series in the emergency setting: a retrospective review

PURPOSE

The abdominal series (AXR) remains a frequently ordered test in the emergency department (ED), despite existing literature questioning its utility. The aim of this study was to characterize the use of the AXR in the ED by quantifying how often it is ordered and the frequency of subsequent imaging. Additionally, a time estimate in ED associated with the AXR was quantified. We hypothesized that there would be a low clinical utility of the AXR, and long associated time period spent in the ED.

METHODS

A retrospective audit of AXRs performed in the ED from January to December 2019 was performed. The local picture archiving and communication system (PACS) and electronic medical record were used to collect the variables.

RESULTS

Of 701 AXRs, 438 (62.4%) were reported normal, and 263 (37.6%) were abnormal. A Chi Squared test showed that the two variables (abdominal series result and follow up imaging completion) were significantly related, with p < 0.001. However, the effect size was small (Nagelkerke R square = 0.022). The average time spent in the ED for these patients was 7.27 h, and the average time between the AXR being ordered and interpreted was 1.31 h.

CONCLUSION

The majority of AXRs were reported as normal. Our results showed that AXR had a statistically significant, but low clinically significant predictive ability on subsequent imaging ordering. This supports our hypothesis that the AXR is of low clinical utility with respect to the rate of ordering follow up imaging. The AXR also translated to a quantifiable time interval during the patient's stay in ED. Minimizing overuse of the AXR may result in a decrease in patient duration in the ED.

The effect of erect abdomen radiography on absorbed doses to internal organs and tissues: A clinical study

BACKGROUND

As low as reasonably achievable principles (ALARA) should be applied during all X-ray examinations. In some institutions, an acute abdomen series includes both erect and supine radiography. The purpose of the study was to evaluate the effect of an erect position on absorbed dose to internal abdominal organs when compared with the supine position.

MATERIAL AND METHODS

A prospective study was undertaken where 81 patients were imaged in both supine and erect positions. The PCXMC Monte Carlo software was used to estimate individual organ doses using dose area product (DAP). Absorbed doses were calculated for the large intestines, active bone marrow, liver, lungs, small intestine, stomach, gallbladder, breasts, uterus, ovaries, urinary bladder, kidneys, testicles, and prostate.

RESULTS

The results showed a significant increase of absorbed dose by 1.4% when moving from a supine to an erect position. The testes were found to be the organs most affected by the erect position and then the urinary bladder.

CONCLUSIONS

According to the study's findings, using the erect position during abdominal radiography increases the radiation dose for all of the selected organs compared to using a supine position. Therefore, it is advised that the use of erect abdomen radiography be restricted to certain circumstances.

Acute small bowel obstruction: one-year retrospective study of admissions to inner city Royal Perth Hospital

BACKGROUND

Analyse admissions to Royal Perth Hospital (RPH) with acute small bowel obstruction (SBO), and identify trends between outcomes and management.

METHODS

Retrospective, single-centre review of patients admitted to RPH with acute SBO, between May 2017 and May 2018.

RESULTS

A total of 251 admissions met inclusion criteria. Increasing age correlated with increasing total length of stay (LOS) (r = 0.134, P = 0.033) and post-operative LOS (r = 0.349, P < 0.0001). Increasing age led to poorer outcomes (P < 0.0001). Diagnoses were most commonly adhesions (167/251 = 66.5%), hernias (47/251 = 18.7%) and inflammatory bowel diseases (11/251 = 4.4%). Operation rate for adhesional SBO was 24.6% (41/167) and non-adhesional SBO 54.8% (46/84). Median total LOS for operative versus conservative management was 9 days (interquartile range (IQR) 8) versus 3 days (IQR 3) (P < 0.0001). Median time to surgery was 1 day (IQR 2). Increased time from admission to theatre led to increasing post-operative LOS (r = 0.398, P = 0.0013). Median post-operative LOS for bowel resection versus no resection was 9 days (IQR 4.5) versus 6 days (IQR 4) (P = 0.0128). Of 101, 81 (80.2%) adhesional SBO resolved non-operatively after receiving Gastrografin, compared to 45 of 66 (68.2%) of those who did not (P = 0.07). It did not significantly alter total or post-operative LOS (P = 0.65 and P = 0.96), patient outcome (P = 0.26), or need for bowel resection (P = 0.63).

CONCLUSIONS

Operative management, bowel resection, older age and increasing time from admission to surgery increase LOS. Trial of Gastrografin in non-operative management of adhesion type small bowel obstructions does not significantly affect outcomes but tends to reduce operative rates.

Abdominal radiographs in the emergency department: current status and controversies

This editorial is discussing about the indiscriminate use of abdominal radiographs in the emergency department in general, with focus on value of the erect abdominal radiograph for the diagnosis of mechanical bowel obstruction and paralytic ileus.

The value of the erect abdominal radiograph for the diagnosis of mechanical bowel obstruction and paralytic ileus in adults presenting with acute abdominal pain

INTRODUCTION

There is discord on the value of the erect abdominal radiograph for diagnosing acute abdominal pathologies. The erect radiograph can be uncomfortable for patients in pain and increases patient radiation dose.

AIM

To determine if including the erect abdominal radiograph in plain abdominal radiography (PAR) improved diagnostic accuracy for identifying mechanical bowel obstruction and/or paralytic ileus in adults presenting with acute abdominal pain.

METHODS

PAR of 40 consecutive adults presenting with suspected bowel obstruction or paralytic ileus was retrospectively sampled and independently reviewed by two emergency department (ED) consultants and two radiology consultants for bowel obstruction and paralytic ileus across two sessions. In session 1, the assessors assessed the supine abdominal radiographs (PAR 1) and clinical details in a randomised order, and session 2, at least 6 weeks later, they assessed the supine and erect radiographs (PAR 2) and clinical details of the randomly re-ordered cases. Computed tomography was the reference standard. Pair-wise comparisons of receiver operating characteristic curves were calculated to assess for significant differences in participants' diagnostic accuracy using MedCalc 16.4.3.

RESULTS

Average sensitivity, specificity and area under the receiver operating characteristic curves (AUROC) were 69.7%, 61.0% and 0.642 for PAR 1, respectively, and 80.0%, 53.4% and 0.632 for PAR 2 respectively. For AUROC there were no significant differences (P > 0.05) between PAR 1 and PAR 2. Intra-rater and inter-rater agreement improved in PAR 2.

CONCLUSION

There was no statistically significant improvement in diagnostic accuracy when including the erect radiograph in PAR for the acute abdomen.

Diagnostic accuracy of low-dose CT compared with abdominal radiography in non-traumatic acute abdominal pain: prospective study and systematic review

OBJECTIVES

Abdominal radiography is frequently used in acute abdominal non-traumatic pain despite the availability of more advanced diagnostic modalities. This study evaluates the diagnostic accuracy of low-dose CT compared with abdominal radiography, at similar radiation dose levels.

METHODS

Fifty-eight patients were imaged with both methods and were reviewed independently by three radiologists. The reference standard was obtained from the diagnosis in medical records. Sensitivity and specificity were calculated. A systematic review was performed after a literature search, finding a total of six relevant studies including the present.

RESULTS

Overall sensitivity with 95 % CI for CT was 75 % (66-83 %) and 46 % (37-56 %) for radiography. Specificity was 87 % (77-94 %) for both methods. In the systematic review the overall sensitivity for CT varied between 75 and 96 % with specificity from 83 to 95 % while the overall sensitivity for abdominal radiography varied between 30 and 77 % with specificity 75 to 88 %.

CONCLUSIONS

Based on the current study and available evidence, low-dose CT has higher diagnostic accuracy than abdominal radiography and it should, where logistically possible, replace abdominal radiography in the workup of adult patients with acute non-traumatic abdominal pain.

KEY POINTS

• Low-dose CT has a higher diagnostic accuracy than radiography. • A systematic review shows that CT has better diagnostic accuracy than radiography. • Radiography has no place in the workup of acute non-traumatic abdominal pain.

Free air on plain film: Do we need a computed tomography too?

Context:

Standard teaching is that patients with pneumoperitoneum on plain X-ray and clinical signs of abdominal pathology should undergo urgent surgery. It is unknown if abdominal computed tomography (CT) provides additional useful information in this scenario.

Aims:

The aim of this study is to determine whether or not CT scanning after identification of pneumoperitoneum on plain X-ray changes clinical management or outcomes.

Settings and Design:

Retrospective study carried out over 4 years at a tertiary care academic medical center. All patients in our acute care surgery database with pneumoperitoneum on plain X-ray were included. Patients who underwent subsequent CT scanning (CT group) were compared with patients who did not (non-CT group).

Statistical Analysis Used:

The Wilcoxon rank-sum test, t-test and Fisher's exact test were used as appropriate to compare the groups.

Results:

There were 25 patients in the non-CT group and 18 patients in the CT group. There were no differences between the groups at presentation. All patients in the non-CT group underwent surgery, compared with 83% (n = 15) of patients in the CT group (P = 0.066). 16 patients in the non-CT and 11 patients in the CT group presented with peritonitis and all underwent surgery regardless of group. For patients undergoing surgery, there were no differences in outcomes between the groups. After X-ray, patients undergoing CT required 328.0 min to arrive in the operating room compared with 136.0 min in the non-CT group (P = 0.007).

Conclusions:

In patients with pneumoperitoneum on X-ray and peritonitis on physical exam, CT delays surgery without providing any measurable benefit.

Clinical value of CT in early diagnosis and treatment of acute abdomen

It is critical to select a fast and accurate method for the early diagnosis and treatment of acute abdomen. CT displays important application value in the early diagnosis and treatment of acute abdomen because of its convenient and intuitive features, advantages in terms of sensitivity and specificity compared with other methods, and the relatively low economic cost. In this paper, we summarize the application value of abdominal CT in the early diagnosis and treatment of acute abdomen by analyzing the characteristics of acute abdomen, comparing CT examination with other methods, and presenting several specific cases.

Diagnostic value of CT versus BUS in detection of acute appendicitis

AIM: To compare the diagnostic value of CT versus BUS in detection of acute appendicitis.

METHODS: Clinical data for 120 patients with pathologically verified acute appendicitis who underwent CT ( n = 60) or BUS ( n = 60) were retrospectively analyzed to compare the value of CT and BUS in diagnosis and differential diagnosis of this disease. The sensitivity of the two modalities in the diagnosis of acute appendicitis was compared.

RESULTS: The sensitivity of CT and BUS in the diagnosis of acute appendicitis was 93% and 60%, respectively. The diagnostic accuracy of CT for acute appendicitis was significantly better than that of BUS (P < 0.05). However, there was no significant difference in diagnostic accuracy between CT and BUS for other pathologic types of appendicitis.

CONCLUSION: CT should be the first choice for acute appendicitis, especially in patients with a negative BUS examination.

Is fluoroscopic imaging mandatory for endoscopic treatment of ureteral stones?

OBJECTIVE

To present the feasibility and safety of fluoro-less endoscopic treatment of ureteral stones to diminish radiation exposure of the patient and operating team, and to determine circumstances where a fluoroscopic imaging is mandatory.

METHODS

Between 2010 and 2011, 93 patients with ureteral calculi who underwent ureteroscopic treatment by experienced urologists were retrospectively evaluated. Manipulations, such as guidewire, ureteral stent insertion, and balloon dilatation were performed with visual and tactile cues. Patient demographics, need for fluoroscopic imaging, operation and fluoroscopy time, and complication and success rates were investigated.

RESULTS

The mean age of patients was 34.03 ± 12.09 years (range, 9-63 years). The mean stone size was 10.64 ± 3.16 mm (range, 6-17 mm). The stones were localized in the proximal, middle, and distal segments in 11, 30, and 52 patients, respectively. The mean duration of the operation was 34.51 ± 7.94 minutes (range, 24-55 minutes). Stone-free status was achieved for 90 patients (96.77%). Fluoroscopic imaging was required for 7 patients with a mean fluoroscopy time of 9 ± 4.72 seconds (range, 4-16 seconds) for the following reasons: stone migration to the kidney (3 patients), double collecting system with 2 ureters (1 patient), and ureteral orifice stricture extending to the upper segment (1 patient). No major complications were observed, but minor complications were observed in 11 patients (11.8%).

CONCLUSION

The ureteroscopic treatment of ureteral stones can be safely and effectively performed in experienced hands, with limited or no usage of fluoroscopy except in special circumstances, such as anatomic abnormalities, upper ureteral strictures, and impacted ureteral stones leading to ureteral tortuosity, kinking, and obstruction.