Unenhanced Helical CT Research Articles

Acute Ureterolithiasis: Incidence of Secondary Signs on Unenhanced Helical CT and Influence on Patient Management

Acute Ureterolithiasis: Incidence of Secondary Signs on Unenhanced Helical CT and Influence on Patient Management

Diagnostic Value of Attenuation Measurements of the Kidney on Unenhanced Helical CT of Obstructive Ureterolithiasis

Diagnostic Value of Attenuation Measurements of the Kidney on Unenhanced Helical CT of Obstructive Ureterolithiasis

ECG-Gated 16-MDCT of the Coronary Arteries: Assessment of Image Quality and Accuracy in Detecting Stenoses

The aim of this study was to investigate image quality and diagnostic accuracy in detecting coronary artery lesions using a 16-MDCT scanner. Thirty-seven patients (28 men, nine women) underwent unenhanced helical CT and MDCT angiography of the coronary arteries. After patients received oral beta-blocker medication, CT scans were obtained during a single breath-hold with a 16-MDCT scanner using ECG-gating (0.75-mm collimation, 2.8-mm table feed/rotation, 0.42-sec rotation time). The image quality was assessed in terms of artifacts and segment visibility by two reviewers. Stenosis severity was compared with the results of conventional invasive coronary angiography. The data evaluation of the image quality was based on a total of 488 segments, of which 380 segments were considered to have diagnostic image quality. One hundred eight segments (22.1%) could not be sufficiently evaluated because of severe calcifications (35 segments) and motion artifacts (73 segments). The mean calcium score (Agatston score equivalent [ASE]) was 524.3 +/- 807.6. Twenty-eight (75.7%) of the 37 patients had an ASE of less than 1,000 (mean ASE, 90.8 +/- 152.3 [SD]), and nine (24.3%) patients had an ASE of 1,000 or greater (mean ASE, 1,761.0 +/- 637.6). For detecting lesions 50% or greater (without any exclusion criteria), the overall sensitivity, specificity, positive predictive value, and negative predictive value were 59%, 87%, 61%, and 87%, respectively. When limiting the number of patients to those with a calcium score of less than 1,000 ASE, the threshold-corrected sensitivity for lesions 50% or greater was 93%; specificity, 94%; positive predictive value, 68%; and negative predictive value, 99%. In patients with no or moderate coronary calcification, MDCT of coronary arteries using 16-MDCT technology allows the reliable detection of coronary artery stenoses with high diagnostic accuracy. Obtaining an initial unenhanced scan was found to be mandatory to avoid performing useless examinations in patients with severe calcifications.

1718: Unenhanced Helical CT in Patients with Acute Flank Pain: Is it Always a Stone that Explains this Symptom?

1718: Unenhanced Helical CT in Patients with Acute Flank Pain: Is it Always a Stone that Explains this Symptom?

Clinical impact of incidental diagnosis of disease on non-contrast-enhanced helical CT for acute ureteral colic

The role of un enhanced helical CT (UHCT) in the evaluation of acute flank pain suggestive of urinary tract calculi is increasingly appreciated in the last few years. Recent studies have identified the advantages of UHCT in recognizing alternative findings within or outside the urinary tract. These incidental diagnoses on UHCT alter a patient's management and demonstrate the pivotal role of UHCT in rapidly triaging these patients for appropriate management. Clinical impact of incidental diagnoses is maximal in identifying alternate emergent conditions mimicking reno-ureteric colic and in identifying malignancies at an early stage when they are potentially curable.

Vesicouterine Fistulas: Imaging Findings in Three Cases

The objective of our report is to present three cases of vesicouterine fistulas secondary to a cesarean delivery, a uterine rupture during labor, and radiation therapy. The delay between the onset of symptoms and the diagnosis varied between 3 and 7 years. Different techniques such as color Doppler sonography, excretory urography, cystography, CT, MRI, cystoscopy, vaginoscopy, and hysterography were performed with variable results, mostly negative and sometimes undefined. The definitive diagnosis was made with contrast-enhanced helical CT after cystography in one case, unenhanced helical CT after hysterography in another case, and cystography in the third case. Vesicouterine fistula rarely is thought of in the differential diagnosis because of its rarity and negative results on radiologic and endoscopic tests. The diagnosis is made on imaging after opacification of the uterus or the bladder depending on the pressure gradient obtained and the location of the fistula in relation to the uterine isthmus.

Unenhanced Helical CT In Renal Colic

Aim: For quite a few years now, CT has established itself as an imaging modality for renal colic. At our institution (a tertiary referral for urology) ,CT has been used for approximately 6-7 years as a diagnostic test for renal/ureteric calculi. The aim of our study was to determine the impact of CT on patient management. Materials And Methods: Retrospective review of case notes of 100 patients who underwent CT for a clinical diagnosis of renal colic. Results: We found that calculi greater than 5mm in size (23) were more likely to cause hydronephrosis and/or hydroureter (17,70%),and less likely to pass spontaneously, thereby requiring some form of intervention ( 15,65%);conversely, those less than 5mm in size (22) benefited from conservative management (14,63%).Calculi greater than 5mm in size were often visualised on plain films (20,87%);smaller calculi could only be seen on CT. The study did not reveal that there were a significant number of relevant alternative diagnoses made on the CT (8,16%). 90% (45) of patients with no calculus on CT (50 in total) were not admitted again. Conclusion: CT is an accurate modality for the diagnosis of, and a powerful tool to rule out the presence of a urinary calculus. Size of calculus is important; calculi larger than 5mm are likely to need intervention. Radiation dose remains an issue, especially with follow-up of small, less than 5mm calculi, which are not readily visible on plain films. Urologists' awareness regarding radiation implications and the necessity of restricting additional investigations is important.

Normal Ureter Size on Unenhanced Helical CT

Normal Ureter Size on Unenhanced Helical CT

Invited Commentary • Authors' Response

Acute pain due to an obstructing ureteral calculus is a very common problem, with a lifetime prevalence in the United States of up to 12%. Renal colic is therefore one of the most common conditions treated in emergency departments (1,2). An obstructing ureteral calculus may mimic, and be mimicked by, innumerable abdominal and pelvic conditions. Patient history, physical examination, and laboratory tests cannot help confirm or exclude the diagnosis with high enough accuracy (1,2). In particular, hematuria testing has a sensitivity of 81%–84% (3,4) and a specificity and negative predictive value of 48% and 65%, respectively (4), and numerous alternative conditions commonly produce hematuria as well. First introduced in 1995 by Smith et al (5), unenhanced CT (followed by unenhanced helical CT and unenhanced multi–detector row CT) has become the imaging modality of choice for the evaluation of patients with flank pain. Unenhanced CT is faster, safer, and more accurate than excretory urography and does not carry the risk of a contrast material reaction. As a result, excretory urography is almost never performed for this indication nowadays. Other advantages of unenhanced helical CT include more precise sizing and localizing of stones, determination of overall stone burden, and a comparable or reduced radiation dose (1,2,5–7). The examination can also be used to guide subsequent patient treatment based on the size and location of a ureteral stone. The most important advantage of unenhanced helical CT may be its capacity to reveal alternative diagnoses, both within and outside the genitourinary tract. Many of these diagnoses would not be evident at radiography or excretory urography (8–10). Rucker et al (11) beautifully document a broad spectrum of alternative diagnoses discovered at unenhanced helical CT over a 2-year period in patients who were initially suspected of having an obstructing ureteral stone. These alternative diagnoses include common disorders such as pyelonephritis, appendicitis, and ovarian lesions, uncommon diagnoses such as renal lymphoma and ascending colonic diverticulitis, and rare diagnoses such as acute spontaneous splenic rupture and hemorrhage due to a renal arteriovenous malformation. Some relatively recent cases from our S28 October 2004 RG f Volume 24 ● Special Issue

Editorial comment

Noncontrast enhanced helical CT scanning will detect urinary tract stones in roughly 95% to 98% of patients who have them. 1 Fielding J.R. Steele G. Fox L.A. et al. Spiral computerized tomography in the evaluation of acute flank pain a replacement for excretory urography. J Urol. 1997; 157: 2071-2073 Abstract Full Text Full Text PDF PubMed Scopus (215) Google Scholar , 2 Dalrymple N.C. Verga M. Anderson K.R. et al. The value of unenhanced helical computerized tomography in the management of acute flank pain. J Urol. 1998; 159: 735-740 Abstract Full Text Full Text PDF PubMed Scopus (297) Google Scholar Making an accurate diagnosis in the remaining 2% to 5% of patients with undetected urinary tract stones represents a diagnostic challenge. In these uncommon cases, urologists and radiologists must rely on “secondary” signs of ureteral obstruction. Historically, these signs have included hydronephrosis, hydroureter, unilateral renal enlargement, perinephric stranding, periureteral stranding, and the ureteral tissue rim sign. Of these signs, however, only hydronephrosis and hydroureter occur with relative frequency (70% to 90% of cases) and, hence, have a reasonably high sensitivity. 3 Ege G. Akman H. Kuzucu K. et al. Acute ureterolithiasis incidence of secondary signs on unenhanced helical CT and influence on patient management. Clin Radiol. 2003; 58: 990-994 Crossref PubMed Scopus (55) Google Scholar The other signs occur with less frequency and are, therefore, only helpful if they are present (high specificity but low sensitivity).

Diagnostic accuracy of ultrasonography compared to unenhanced CT for stone and obstruction in patients with renal failure.

BackgroundTo determine accuracy of ultrasound (US) kidney, ureter and bladder (KUB) compared to un-enhanced helical CT (UHCT) in patients with renal failure in the diagnosis of stone and obstruction.MethodsThis is a case controlled study conducted in the period from June 2000 to July 2003 at a university hospital. All patients had both US and UHCT scan. Patients with serum creatinine ≥ 1.8 mg/dl were included in the study. Only direct visualization of stone was considered as confirmatory. In both the studies, UHCT and US, presence of stone and obstruction were noted. The relevant biochemicals, radiological and clinical records of all the patients were analyzed. Data was analyzed using commercially available software.ResultsDuring the period of study 864 patients had UHCT for evaluation of the urinary tract in patients presenting with flank pain. Out of these 34 patients had both UHCT and US done within a span of one day and had serum creatinine of ≥1.8 mg/dl. Mean age was 48 ±15.8 years and 59% of patients were males. UHCT identified renal stones in 21 (62%), whereas 17 of these were identified on US, with a sensitivity of 81%. Of the four patients with renal stones missed on US, three were identified on plain x-ray; the mean size of stones missed was 6.3 mm. Of the 22 (65%) patients with ureteric stone on UHCT, US could only identify 10; a further 7 were identified on x-ray KUB, giving a sensitivity of 45% (US alone) and 77% (US with x-ray KUB).ConclusionsUS is sensitive and specific for renal stones, 81% and 100% and for hydronephrosis, 93% and 100%, respectively. Its sensitivity to pick ureteric stone (46%) and to identify hydroureter (50%) is low. Addition of x-ray KUB abdomen increases the sensitivity for ureteric stones to 77%.

Diagnostic value of attenuation measurements of the kidney on unenhanced helical CT of obstructive ureterolithiasis.

The objective of this study was to assess the diagnostic value of attenuation measurements of the kidney on unenhanced helical CT in patients with obstructive ureterolithiasis. Consecutive unenhanced helical CT scans of patients referred for acute unilateral renal colic were retrospectively reviewed. Patients with CT evidence of other urinary system diseases were excluded. Included scans (n = 145) were assessed for ureteral stone and secondary signs of obstruction such as unilateral collecting system or ureteral dilatation, perinephric stranding, and periureteral edema. Renal attenuation in Hounsfield units was measured in the upper, middle, and lower portions of the parenchyma, and a mean value was determined for each kidney. Ureteral stones were present in 76 patients. Renal attenuation on the side with lithiasis was lower than on the opposite kidney: 27.2 +/- 3.9 H vs 32.6 +/- 3.4 H (p < 0.001). Attenuation differences between kidneys were higher for patients with ureterolithiasis: 5.4 +/- 3.2 H (range, -3.3 to 13.0 H) versus 1.2 +/- 1.0 H (range, 0-4.7 H) (p < 0.001). An attenuation difference between kidneys greater than or equal to 5.0 H had 61% sensitivity, 100% specificity, 100% positive predictive value, 69% negative predictive value, and 79% accuracy for diagnosis of ureteral lithiasis. Attenuation difference between kidneys greater than or equal to 5.0 H was a valuable sign and had diagnostic performance similar to other secondary signs of obstructive ureterolithiasis. Furthermore, attenuation difference had the advantage of being an objective, measurement-based indicator.

Functional evaluation of the urinary tract by color-Doppler ultrasonography (CDU) in 100 patients with renal colic

Introduction and objective: To evaluate if the addition of a renal color-Doppler ultrasonography (CDU) in the setting of acute renal colic improves the sensitivity of conventional sonography. Materials and methods: Between July 2002 and June 2003, 100 patients (median 49 years) with renal colic have been evaluated. Within 24 h of the admission, a CDU study of the urinary tract was performed using a sonograph GE Logiq 500 PRO with a multifrequency (3–5 MHz) convex probe. The following parameters were evaluated: ultrasonography (US) of both kidneys, ureters and bladder; resistive index (RI) of the arciform arteries of both kidneys in three different parenchymal areas; ureteric jets in response to hydration. A renal RI >0.70 and/or a 10% difference between the kidneys were considered as diagnostic of obstructive uropathy; an asymmetric and/or reduced ureteric jet from the ureteric orifices was an additional indicator of obstruction. All patients underwent a CT scan both with and without the administration of contrast medium. Results: Enhanced helical CT demonstrated an urinary stone in 90 out of the 100 patients (90%): 29 pyelic, 28 at the pyelo-ureteral junction, 23 lumbo-iliac and 10 juxtavesical stones. Among 90 patients with urolithiasis, the stone was undetectable with US in 11 cases (12.2%); in 8 cases (8.9%) pyelocalicectasis was absent, and in 6 patients (6.6%) a non-obstructive hydronephrosis was present. Median RI in obstructed and non-obstructed kidney was 0.73 (range 0.71–0.87) versus 0.62 (0.50–0.68), respectively; in two, obstructed kidneys RI was <0.70 but greater than 10% compared with normal side. Sensitivity and specificity of US, CDU (RI + ureteric jet), unenhanced helical CT and CDU in association with unenhanced helical CT were 94.8 and 55.5, 98.9 and 90.9, 100 and 100%, respectively. Discussion and conclusions: CDU in patients with renal colic and/or pelvicalicectasis improves the diagnostic accuracy of US in distinguishing between obstructive and non-obstructive dilatation. Combined with unenhanced CT, CDU has a 100% sensitivity and specificity. Moreover, due to the absence of contraindications and side-effects, CDU is indicated for the follow-up of patients after ESWL, pregnant women and children.

Normal ureter size on unenhanced helical CT.

Unenhanced helical CT is the imaging method of choice when evaluating patients with acute flank pain and suspected ureterolithiasis. In addition to directly identifying stones in the lumen of the ureter, CT secondary signs of obstruction such as ureteral dilatation are frequently present and can be helpful in establishing a diagnosis. The purposes of this study were to define ureteral dilatation on unenhanced helical CT and determine the range of normal ureter size. We retrospectively reviewed the unenhanced helical CT studies of 212 consecutive patients with acute flank pain whose CT scans showed acute ureterolithiasis. The size of the ureter was determined on the asymptomatic side as well as on the obstructed side. Mean ureteral diameter was determined as the largest transverse dimension along the course of the ureter beginning 1-2 cm below the ureteropelvic junction. The mean size of ureters on the asymptomatic side was 1.8 mm with a standard deviation (SD) of 0.9 mm. The mean size of ureters on the obstructed side was 7 mm with an SD of 3.2 mm. In 96% of patients, the ureter diameter on the asymptomatic side was 3 mm or smaller. Three millimeters should be considered the upper limit of normal size for nonobstructed ureters on unenhanced helical CT.

The soft-tissue rim sign.

HomeRadiologyVol. 229, No. 1 PreviousNext Signs in ImagingThe Soft-Tissue Rim SignNizar A. Al-NakshabandiNizar A. Al-NakshabandiAuthor Affiliations1From the Department of Radiology, Abdominal Division, Vancouver Hospital and Health Science Centre, British Columbia, Canada. Received June 9, 2002; revision requested July 16; final revision received October 2; accepted October 22. Address correspondence to the author, Department of Radiology, College of Medicine, King Saud University, Riyadh 11461, Saudi Arabia (e-mail: [email protected]).Nizar A. Al-NakshabandiPublished Online:Oct 1 2003https://doi.org/10.1148/radiol.2291020690MoreSectionsFull textPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In References 1 Kawashima A, Sandler C, Boridy IC, Takahashi N, Benson GS, Goldman SM. Unenhanced helical CT of ureterolthiasis: value of the tissue rim sign. AJR Am J Roentgenol 1997; 168:997-1000. Crossref, Medline, Google Scholar2 Heneghan JP, Dalrymple NC, Verga M, Rosenfield AT, Smith RC. Soft-tissue rim sign in the diagnosis of ureteral calculi with use of unenhanced helical CT. Radiology 1997; 202:709-711. Link, Google Scholar3 Smith RC, Levine J, Rosenfeld AT. Helical CT of urinary tract stones. Radiol Clin North Am 1999; 37:911-949. Crossref, Medline, Google Scholar4 Spencer BA, Wood BJ, Dretler SP. Helical CT and ureteral colic. Radiol Clin North Am 2000; 27:1-12. Google Scholar5 Bell TV, Fenlon HM, Davison BD, Ahari HK, Hussain S. Unenhanced helical CT criteria to differentiate distal ureteral calculi from pelvic phleboliths. Radiology 1998; 207:363-367. Link, Google Scholar6 Smith RC, Verga M, Dalrymple N, McCarthy S, Rosenfield A. Acute ureteral obstruction: value of secondary signs on helical CT. AJR Am J Roentgenol 1996; 167:1109-1113. Crossref, Medline, Google ScholarArticle HistoryPublished in print: Oct 2003 FiguresReferencesRelatedDetailsCited ByClinical study on ureteritis observed in contrast-enhanced computed tomography in the emergency departmentJihyukChung, Ji UngNa, Jang HeeLee, Sang KukHan, Pil ChoChoi, Dong HyukShin2022 | Clinical and Experimental Emergency Medicine, Vol. 9, No. 3Classic Imaging SignsXinLi, ChengkaiZhou, JieZhou2021Secondary signs on preoperative CT as predictive factors for febrile urinary tract infection after ureteroscopic lithotripsyJin WooKim, You JinLee, Yun-SokHa, Jun NyungLee, Hyun TaeKim, So YoungChun, Bum SooKim2020 | BMC Urology, Vol. 20, No. 1Factors predicting the spontaneous passage of a ureteric calculus of ⩽10 mmAbul-fotouhAhmed, Ahmed H.Gabr, Abdel-AzizEmara, MahmoudAli, Al-SayedAbdel-Aziz, SaadAlshahrani2015 | Arab Journal of Urology, Vol. 13, No. 2Computed Tomographic Imaging of Renal and Ureteral EmergenciesNetanel S.Berko, Robert J.Dym2015 | Current Problems in Diagnostic Radiology, Vol. 44, No. 2Radiopaedia.orgAylaAl Kabbani, DavidPuyó2013Comparison of secondary signs as shown by unenhanced helical computed tomography in patients with uric acid or calcium ureteral stonesYii-HerChou, Wei-PoChou, Mu-EnLiu, Wei-MingLi, Ching-ChiaLi, Chia-ChuLiu, Yung-ShunJuan, Shu-ChingPan2012 | The Kaohsiung Journal of Medical Sciences, Vol. 28, No. 6Secondary signs during non-enhanced helical computed tomography in the diagnosis of ureteral stonesYii-HerChou2012 | Urological Science, Vol. 23, No. 4Usefulness of Early Extracorporeal Shock Wave Lithotripsy in Colic Patients with Ureteral StonesHyeung JoonChoi, Jin-HeeJung, JungbumBae, Min ChulCho, Hae WonLee, Kwang SooLee2012 | Korean Journal of Urology, Vol. 53, No. 12Low-Dose Versus Standard-Dose CT Protocol in Patients with Clinically Suspected Renal ColicPierre-AlexandrePoletti, AlexandraPlaton, Olivier T.Rutschmann, Franz R.Schmidlin, Christophe E.Iselin, Christoph D.Becker2007 | American Journal of Roentgenology, Vol. 188, No. 4Fundamentals of Body CTWilliam E.Brant2006Recommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 229, No. 1 Metrics Altmetric Score PDF download

Incidental diagnosis of diseases on un-enhanced helical computed tomography performed for ureteric colic.

BackgroundPatients presenting in the emergency room with flank pain suggestive of acute ureteric colic may have alternative underlying conditions mimicking ureteric stones. An early diagnosis and appropriate treatment for other causes of flank pain is important. The majority of centers around the world are increasingly using un-enhanced helical CT (UHCT) for evaluation of ureteric colic. This study was conducted to determine the incidence and spectrum of significant incidental diagnoses established or suggested on UHCT performed for suspected renal/ureteric colic.MethodsUrologist and radiologist reviewed 233 consecutive UHCT, performed for suspected renal/ureteral colic along with assessment of the medical records. Radiological diagnoses of clinical entities not suspected otherwise were analyzed. All other relevant radiological, biochemical and serological investigations and per-operative findings were also noted.ResultsUreteral calculi were identified in 148 examinations (64%), findings of recent passage of calculi in 10 (4%) and no calculus in 75 examinations (32%). Overall the incidental findings (additional or alternative diagnosis) were found in 28 (12%) CT scans. Twenty (71%) of these diagnoses were confirmed by per-operative findings, biopsy, and other radiological and biochemical investigations or on clinical follow up.ConclusionA wide spectrum of significant incidental diagnoses can be identified on UHCT performed for suspected renal/ureteral colic. In the present series of 233 consecutive CT examinations, the incidence of incidental diagnosis was 12%.

Alternative Pathologies on Unenhanced Helical CT Scan in Patients Presenting With Flank Pain

Alternative Pathologies on Unenhanced Helical CT Scan in Patients Presenting With Flank Pain

Unenhanced Helical CT Is Accurate for Diagnosing Appendicitis

As imaging techniques for diagnosing appendicitis become more refined, the need for contrast is coming under increased scrutiny. These authors

MRCP and ERCP in the diagnosis of common bile duct stones

Common bile duct stones have been reported to occur in up to 15% of patients with symptomatic gallstones. 1 Ahrendt SA Pitt HA. Biliary tract. in: 16th ed. Sabiston textbook of surgery: the biological basis of modern surgical practice. WB Saunders, Philadelphia2001: 1076-1111 Google Scholar Although the sensitivity of abdominal US for cholelithiasis or gallbladder stones is in excess of 95%, 2 Cooperberg PL Burhenne HJ. Real-time ultrasonography. Diagnostic technique of choice in calculous gallbladder disease. N Engl J Med. 1980; 302: 1277-1279 Crossref PubMed Scopus (202) Google Scholar , 3 Crade M Taylor KJW Rosenfield AT de Graaff CS Minihan P. Surgical and pathologic correlation of cholecystosonography and cholecystography. AJR Am J Roentgenol. 1978; 131: 227-229 Crossref PubMed Scopus (99) Google Scholar , 4 McIntosh DMF Penney HF. Gray scale ultrasonography as a screening procedure in the detection of gallbladder disease. Radiology. 1980; 136: 725-727 Crossref PubMed Scopus (59) Google Scholar reported sensitivities of US for common duct stones range from 18% to 74%. 5 Laing FC. The gallbladder and bile ducts. in: 2nd ed. Diagnostic ultrasound. Mosby-Year Book, St. Louis1998: 175-223 Google Scholar , 6 Mitchell SE Clark RA. A comparison of computed tomography and sonography in choledocholithiasis. AJR Am J Roentgenol. 1984; 142: 729-733 Crossref PubMed Scopus (84) Google Scholar This variable sensitivity is related in part to the operator-dependent nature of US and the obscuration of stones by bowel gas. Sensitivities of conventional CT in the setting of suspected choledocholithiasis range from 76% to 90%. 7 Baron RL. Common bile duct stones: reassessment of criteria for CT diagnosis. Radiology. 1987; 162: 419-424 Crossref PubMed Scopus (108) Google Scholar , 8 Jeffrey RB Federle MP Laing FC Wall S Rego J Moss AA. Computed tomography of choledocholithiasis. AJR Am J Roentgenol. 1983; 140: 1179-1183 Crossref PubMed Scopus (67) Google Scholar In a preliminary report, unenhanced helical CT has been shown to have a sensitivity of 88%, a specificity of 97%, and an accuracy of 94% in the diagnosis of common bile duct stones. 9 Neitlich JD Topazian M Smith RC Gupta A Burrell MI Rosenfield AT. Detection of choledocholithiasis: comparison of unenhanced helical CT and endoscopic retrograde cholangiopancreatography. Radiology. 1997; 203: 753-757 Crossref PubMed Scopus (133) Google Scholar

Diagnostic value of unenhanced helical CT in adult patients with suspected acute appendicitis.

Clinical diagnosis of appendicitis is usually made on the basis of history, physical examination and laboratory studies. Approximately 30-45% of patients with suspected appendicitis present with atypical clinical and laboratory findings. Recently graded compression ultrasound and thin section unenhanced helical CT have been used to establish diagnosis for patients with suspected acute appendicitis. The purpose of this study was to determine the diagnostic accuracy of thin section unenhanced helical CT protocol in adult patients with suspected acute appendicitis. CT scans obtained when patients presented with right lower quadrant pain and the clinical impression was equivocal for appendicitis were evaluated. Of 296 patients referred for CT, 123 patients subsequently underwent surgery. Appendicitis had been correctly predicted in 104 of 108 patients surgically proven to have appendicitis. Unenhanced helical CT in the diagnosis of acute appendicitis had a sensitivity of 96%, specificity of 98%, positive predictive value of 97% and negative predictive value of 98%. If no definite inflammatory changes are detected, on the basis of our experience we recommend that the patient be monitored clinically, and that thin section unenhanced helical CT is the optimal technique to detect acute appendicitis in adult patients.