Accuracy and radiation dose reduction of a limited abdominopelvic CT in the diagnosis of acute appendicitis

Corwin, Michael T.; Chang, Melanie; Fananapazir, Ghaneh; Seibert, J. Anthony; Lamba, Ramit

doi:10.1007/s00261-014-0280-0

Cited by 18 publications

(15 citation statements)

References 18 publications

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“…In contrast, there are also some diseases with relatively typical patient history and clinical symptoms, offering the potential to focus the scan range on a limited region, in which the expected pathology is most likely located. Promising results exploiting this technique have already been described for different indications, such as appendicitis, pulmonary embolism and urolithiasis, showing a significant dose reduction at similar diagnostic performance [13,24,27]. Our results are in line these studies as all cervical abscesses and alternative/incidental findings present in the full range scan could also be detected in the reduced scan range reconstructions at a significantly reduced dose exposure.…”

Section: Discussionsupporting

confidence: 88%

“…Current approaches for dose reduction focus on examination protocols with automated tube current modulation and automated tube voltage adaption, reduced kVp settings and different iterative reconstruction algorithms [10–12]. Another possibility to effectively reduce dose exposure of CT examinations is to shorten the z-axis scan coverage by excluding those areas, in which the suspected diagnosis is unlikely to occur [13]. Cervical abscesses are most commonly located in the peritonsillar and parapharyngeal region and typical complications involve the adjacent cervical neurovascular pathway and the mediastinum but not the nasopharynx or the skull base [6,14].…”

Section: Introductionmentioning

confidence: 99%

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Effect of reduced z-axis scan coverage on diagnostic performance and radiation dose of neck computed tomography in patients with suspected cervical abscess

et al. 2017

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PurposeTo evaluate the effect of reduced z-axis scan coverage on diagnostic performance and radiation dose of neck CT in patients with suspected cervical abscess.MethodsFifty-one patients with suspected cervical abscess were included and underwent contrast-enhanced neck CT on a 2nd or 3rd generation dual-source CT system. Image acquisition ranged from the aortic arch to the upper roof of the frontal sinuses (CTstd). Subsequently, series with reduced z-axis coverage (CTred) were reconstructed starting at the aortic arch up to the orbital floor. CTstd and CTred were independently assessed by two radiologists for the presence/absence of cervical abscesses and for incidental and alternative findings. In addition, diagnostic accuracy for the depiction of the cervical abscesses was calculated for both readers. Furthermore, DLP (dose-length-product), effective dose (ED) and organ doses were calculated and compared for CTred and CTstd, using a commercially available dose management platform.ResultsA total of 41 abscesses and 3 incidental/alternative findings were identified in CTstd. All abscesses and incidental/alternative findings could also be detected on CTred resulting in a sensitivity and specificity of 1.0 for both readers. DLP, ED and organ doses of the brain, the eye lenses, the red bone marrow and the salivary glands of CTred were significantly lower than for CTstd (p<0.001).ConclusionsReducing z-axis coverage of neck CT allows for a significant reduction of effective dose and organ doses at similar diagnostic performance as compared to CTstd.

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Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Effect of reduced z-axis scan coverage on diagnostic performance and radiation dose of neck computed tomography in patients with suspected cervical abscess

et al. 2017

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“…As it has been shown for other CT applications, 24,25 reducing the acquisition coverage is a simple and effective way of limiting the dose in patients and is recommended in clinical practice. Because of the close relation between scan length and effective dose, when the acquisition length is reduced, a similar reduction in effective dose can be expected.…”

Section: Discussionmentioning

confidence: 99%

“…Because of the close relation between scan length and effective dose, when the acquisition length is reduced, a similar reduction in effective dose can be expected. In a recent study assessing the possibility to reduce the CT scan coverage for acute appendicitis which was also based on T10 anatomical landmark, Corwin et al 24 found that a reduction of the scan coverage of 24% corresponded to a dose reduction of 23%. In addition, by optimizing coverage, it is also possible to reduce the exposure of radiosensitive organs, such as the gonads in males and the breasts in females.…”

Section: Discussionmentioning

confidence: 99%

Optimizing z-axis coverage of abdominal CT scans of the urinary tract: a proposed alternative proximal landmark for acquisition planning

Gervaise¹,

Teixeira²,

Hossu³

et al. 2016

BJR

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Objective: To evaluate an alternative method to reduce the acquisition coverage of urinary tract CT. Methods: This retrospective study included 365 abdominopelvic CT studies. Three radiographers simulated shortened acquisition coverages using three methods to determine the upper limit of the acquisition: Method 1 used the renal contours; Method 2 used the inferior margin of the 10th thoracic vertebra; and Method 3 used the point of intersection of the left diaphragmatic dome and the anterior margin of the vertebral bodies. Reductions in acquisition coverage and number of CT scans with a portion of the kidney excluded from the simulated reduced acquisition were compared between the three methods.Results: The mean 6 standard deviation reduction of acquisition coverage for the three readers with Methods 1, 2 and 3 were 20.5 6 4.8, 15.1 6 6.5 and 18.2 6 5.3%, respectively. Compared with Method 2, Method 3 allowed a mean scan length reduction of 3.6%. The proportions of CT scans with a portion of the kidney excluded from the simulated reduced acquisition with Methods 1, 2 and 3 and averaged over the three readers were 6.7, 0.7 and 1.4%, respectively, with no significant difference between Methods 2 and 3. Interreader and intrareader agreements were excellent with all methods, but interclass correlation coefficients were higher with Method 3. Conclusion: The method using the renal contours should not be used owing to its high proportion of kidneys with a portion excluded from the acquisition. Using the intersection of the left diaphragmatic dome and the anterior margin of the vertebral bodies for proximal landmark for urinary tract CT represents a new alternative method with a better reduction of scan length compared with the method using the inferior margin of T10 and with no significant increase in the number of kidneys with a portion excluded from the reduced acquisition. Advances in knowledge: A new method using the point of intersection of the left diaphragmatic dome and the anterior border of the vertebral bodies on the lateral scout radiograph is introduced to reduce the z-axis coverage of urinary tract CT scans.

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“…This should be done by reducing the tube current-time product, using automated tube current modulation and iterative reconstruction techniques wherever available and limiting the number of scanning phases [8]. In addition, significant dose reduction can be achieved by limiting the z -axis scanning range by focusing on the anatomic ROI [9, 10]. In the case of pregnancy, a large reduction in fetal radiation dose would be expected if scanning could be limited to the maternal upper abdomen.…”

mentioning

confidence: 99%

JOURNAL CLUB: Quantification of Fetal Dose Reduction if Abdominal CT Is Limited to the Top of the Iliac Crests in Pregnant Patients With Trauma

Corwin

Seibert

Fananapazir

et al. 2016

American Journal of Roentgenology

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OBJECTIVE The purposes of this study were to correlate fetal z-axis location within the maternal abdomen on CT with gestational age and estimate fetal dose reduction of a study limited to the abdomen only, with its lower aspect at the top of the iliac crests, compared with full abdominopelvic CT in pregnant trauma patients. MATERIALS AND METHODS We performed a study of pregnant patients who underwent CT of the abdomen and pelvis for trauma at a single institution over a 10-year period. The inferior aspect of maternal liver, spleen, gallbladder, pancreas, adrenals, and kidneys was recorded as above or below the iliac crests. The distance from the iliac crest to the top of the fetus or gestational sac was determined. The CT images of the limited and full scanning studies were independently reviewed by two blinded radiologists to identify traumatic injuries. Fetal dose profiles, including both scatter and primary radiation, were computed analytically along the central axis of the patient to estimate fetal dose reduction. Linear regression analysis was performed between gestational age and distance of the fetus to the iliac crests. RESULTS Thirty-five patients were included (mean age, 26.2 years). Gestational age ranged from 5 to 38 weeks, with 5, 19, and 11 gestations in the first, second, and third trimesters, respectively. All solid organs were above the iliac crests in all patients. In three of six patients, traumatic findings in the pelvis would have been missed with the limited study. There was high correlation between gestational age and distance of the fetus to the iliac crests (R2 = 0.84). The mean gestational age at which the top of the fetus was at the iliac crest was 17.3 weeks. Using the limited scanning study, fetuses at 5, 20, and 40 weeks of gestation would receive an estimated 4.3%, 26.2%, and 59.9% of the dose, respectively, compared with the dose for the full scanning study. CONCLUSION In pregnant patients in our series with a history of trauma, CT of the abdomen only was an effective technique to reduce fetal radiation exposure compared with full abdomen and pelvis CT.

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Accuracy and radiation dose reduction of a limited abdominopelvic CT in the diagnosis of acute appendicitis

Abstract: A limited range CT from the bottom of T10 to the top of the pubic symphysis is as accurate as full abdominopelvic CT in evaluating patients with suspected acute appendicitis and results in approximately 23% dose reduction.

Cited by 18 publications

References 18 publications

Effect of reduced z-axis scan coverage on diagnostic performance and radiation dose of neck computed tomography in patients with suspected cervical abscess

Effect of reduced z-axis scan coverage on diagnostic performance and radiation dose of neck computed tomography in patients with suspected cervical abscess

Optimizing z-axis coverage of abdominal CT scans of the urinary tract: a proposed alternative proximal landmark for acquisition planning

JOURNAL CLUB: Quantification of Fetal Dose Reduction if Abdominal CT Is Limited to the Top of the Iliac Crests in Pregnant Patients With Trauma

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