Low-Dose Nonenhanced Helical CT of Renal Colic: Assessment of Ureteric Stone Detection and Measurement of Effective Dose Equivalent

Liu, Weldon; Esler, Stephen; Kenny, Brian; Goh, Raymond H.; Rainbow, Andrew J.; Stevenson, Giles W.

doi:10.1148/radiology.215.1.r00ap4051

Cited by 153 publications

(92 citation statements)

References 16 publications

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“…Our study shows that less than 2% of CT studies for work-up of kidney stones in this national registry used 3 mSv or less, and nearly 80% of institutions contributed no reduced-dose CT studies. The clinical appropriateness of lower-dose techniques has been demonstrated for more than a decade now; however, our study shows that little progress has been made in the routine clinical application of these techniques in the United States (13). The reduction of dose associated with medical imaging is an important public health and patient safety priority (31), and efforts to use reduced-dose techniques must be strengthened to make meaningful improvements in patient safety.…”

Section: Discussionmentioning

confidence: 93%

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Radiation Dose Index of Renal Colic Protocol CT Studies in the United States: A Report from the American College of Radiology National Radiology Data Registry

Lukasiewicz¹,

Bhargavan-Chatfield²,

Coombs³

et al. 2014

Radiology

103

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Purpose-To determine radiation dose indexes for computed tomography (CT) performed with renal colic protocols in the United States, including frequency of reduced-dose technique usage and any institutional-level factors associated with high or low dose indexes.Materials and Methods-The Dose Imaging Registry (DIR) collects deidentified CT data, including examination type and dose indexes, for CT performed at participating institutions; thus, the DIR portion of the study was exempt from institutional review board approval and was HIPAA compliant. CT dose indexes were examined at the institutional level for CT performed with a renal colic protocol at institutions that contributed at least 10 studies to the registry as of January 2013. Additionally, patients undergoing CT for renal colic at a single institution (with institutional review board approval and informed consent from prospective subjects and waiver of consent from retrospective subjects) were studied to examine individual renal colic CT dose index patterns and explore relationships between patient habitus, demographics, and dose indexes. Descriptive statistics were used to analyze dose indexes, and linear regression and Spearman correlations were used to examine relationships between dose indexes and institutional factors.Results-There were 49 903 renal colic protocol CT examinations conducted at 93 institutions between May 2011 and January 2013. Mean age ± standard deviation was 49 years ± 18, and Address correspondence to C.L.M. (chris.moore@yale.edu). Online supplemental material is available for this article. Author contributions:Guarantor of integrity of entire study, C.L.M.; study concepts/study design or data acquisition or data analysis/interpretation, all authors; manuscript drafting or manuscript revision for important intellectual content, all authors; approval of final version of submitted manuscript, all authors; literature research, A.L., J.W., G.G., C.L.M.; clinical studies, M.G., J.W.; experimental studies, J.W.; statistical analysis, A.L., M.B., L.C., C.L.M.; and manuscript editing, A.L., M.B., L.C., J.W., G.G., C.L.M. The purpose of this study was to determine the radiation dose indexes for CT examinations performed with renal colic protocols in the United States, including how frequently reduceddose techniques are used and any institutional-level factors that are associated with high or low dose indexes. Disclosures of Conflicts of Materials and Methods Study SampleThe Dose Index Registry (DIR), part of the American College of Radiology-sponsored National Radiology Data Registry (www.nrdr.acr.org), receives deidentified data from individual CT examinations performed at participating institutions (21). Participating institutions send anonymized data to the DIR for all CT studies of all types that are performed, barring technical issues or scanner incompatibility. For each submitted study, the DIR includes the type of CT study, the technique factors for each acquisition, estimated CT dose index, and total dose-length product (DLP,...

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Section: Discussionmentioning

confidence: 93%

“…Previous studies have shown that reduced-dose CT studies are accurate for the detection of renal stones (13)(14)(15)(16)(17)(18)(19). A meta-analysis (20) of reduced-dose CT for renal colic (with effective dose less than 3 mSv) yielded a pooled sensitivity and specificity of 0.97 and 0.95, respectively, compared with conventional CT.…”

mentioning

confidence: 98%

Radiation Dose Index of Renal Colic Protocol CT Studies in the United States: A Report from the American College of Radiology National Radiology Data Registry

Lukasiewicz¹,

Bhargavan-Chatfield²,

Coombs³

et al. 2014

Radiology

103

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“…Because the received dose is proportional to the square of the kilovoltage, use of this technique can lead to an approximately 40% increase in received dose, possibly less. The second acquisition thus can be minimal (centered on the stone without acquisition of images of the rest of the abdomen) and performed with low energy (80 kV) [38][39][40]. This additional dose can be a problem for children but can be justified for adult patients because accurate and fast determination of the chemical characterization of renal stones can lead to quicker and more accurate treatment.…”

Section: Grosjean Et Almentioning

confidence: 99%

Characterization of Human Renal Stones with MDCT: Advantage of Dual Energy and Limitations Due to Respiratory Motion

Grosjean

Sauer

Guerra

et al. 2008

American Journal of Roentgenology

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monohydrate stones are more resistant to extracorporeal lithotripsy [16] than are the other types of stones we describe. Failure of extracorporeal shock wave lithotripsy increases medical costs, necessitates alternative treatment, and results in undesirable exposure of the renal parenchyma to shock waves. For these reasons, pretreatment determination of the composition of stones is essential. Since the early 1980s, studies have been conducted to determine stone composition on the basis of X-ray attenuation of stones in vitro [17][18][19][20][21][22] and in vivo [23][24][25].Organs in the upper part of the abdomen, including the liver, kidneys, and spleen, move considerably as a result of respiration [26] MATERIALS AND METHODS. The stones were placed in a jelly simulating the X-ray attenuation of the kidneys. A dynamic platform was used to apply to the phantom free-breathing motion (sinusoidal motion in z-axis) and motion due to lack of maintenance of a breath-hold (5 mm·s −1 in z-axis). Determination of the chemical composition was performed with mean CT attenuation values obtained at 80 and 120 kV and with dual-energy CT attenuation values. G e n it o u r i n a r y I m ag i ng • O r ig i n a l R e s e a rc hRESULTS. Two hundred forty-one human urinary stones were classified into six groups: uric acid, cystine, struvite, weddellite (calcium oxalate dihydrate), whewellite (calcium oxalate monohydrate), and brushite. With no motion, the use of dual energy enabled differentiation of all of the types of stones with statistically significant differences. Uric acid (-20 ± 22 H), cystine (106 ± 19 H), struvite (271 ± 16 H), weddellite (323 ± 5 H), brushite (415 ± 30 H), and whewellite (510 ± 17 H) were identified as distinct groups. Motion-induced mean CT attenuation values were significantly different from those obtained with no motion. With motion, dual-energy CT attenuation values did not allow differentiation of all stone types.CONCLUSION. Dual-energy CT attenuation values can be used to predict the chemical composition of stones in vitro. However, when slight motion is applied to renal stones during image acquisition, the values become significantly different from those obtained with no motion. Consequently, confusion arises in differentiating stone types. A perfect breath-hold has to be performed for in vivo use of attenuation value to discern stone type.

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“…As for pitch, an increase in pitch decreases duration of examination and also decreases radiation exposure to the body. Although increase of pitch causes helical artifacts and decreased spatial resolution, some investigators have reported using a pitch of 2 or above with satisfactory results in cases of suspected renal colic (20,21).…”

Section: Radiation Dose Optimization and Dose Reduction: Alara (As Lomentioning

confidence: 99%

“…X-ray filters decrease "soft X-rays" which never reach the detectors and thus do not contribute to the image. Studies have shown that using effective X-ray filters causes a reduction in the radiation exposure and decrease in noise at a very-low-dose CT (21,24). Automatic tube current modulation can be defined as a set of techniques that enable automatic adjustment of the tube current according to the size and attenuation characteristics of the body part being scanned and achieve constant CT image quality with lower radiation exposure (25).…”

Section: Radiation Dose Optimization and Dose Reduction: Alara (As Lomentioning

confidence: 99%

MDCT technique and imaging findings of urinary stone disease: an expanded review

Türkbey

Akpınar²,

Özer³

et al. 2008

Diagn Interv Radiol

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Low-Dose Nonenhanced Helical CT of Renal Colic: Assessment of Ureteric Stone Detection and Measurement of Effective Dose Equivalent

Abstract: Our low-dose CT protocol is superior to IVU and clinically adequate for diagnosis of renal colic.

Cited by 153 publications

References 16 publications

Radiation Dose Index of Renal Colic Protocol CT Studies in the United States: A Report from the American College of Radiology National Radiology Data Registry

Radiation Dose Index of Renal Colic Protocol CT Studies in the United States: A Report from the American College of Radiology National Radiology Data Registry

Characterization of Human Renal Stones with MDCT: Advantage of Dual Energy and Limitations Due to Respiratory Motion

MDCT technique and imaging findings of urinary stone disease: an expanded review

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