Relationship between duration of pain and secondary signs of obstruction of the urinary tract on unenhanced helical CT.

OBJECTIVE: The objective of this study was to investigate the relationship between duration of flank pain and the frequency of secondary signs of ureteral obstruction on unenhanced helical CT. SUBJECTS AND METHODS: The duration of flank pain was prospectively determined in 227 consecutive patients diagnosed with acute ureterolithiasis on unenhanced helical CT. These CT studies were evaluated for the presence or absence of perinephric stranding, ureteral dilatation, perinephric fluid, collecting system dilatation, periureteral stranding, and nephromegaly. The frequency of each sign was determined as a function of the duration of pain. RESULTS: The frequency of moderate or severe perinephric stranding increased from 5% at 1--2 hr to 51% at 7--8 hr (p < 0.001); ureteral dilatation increased from 84% at 1--2 hr to 97% at more than 8 hr (p < 0.03); moderate or severe perinephric fluid increased from 0% at 1--2 hr to 22% at 3--4 hr (p < 0.03); collecting system dilatation increased from 68% at 1--2 hr to 89% at 7-8 hr (p < 0.03); periureteral stranding increased from 35% at 1--2 hr to 76% at 7--8 hr (p < 0.004); and nephromegaly increased from 40% at 1--2 hr to 54% at 7--8 hr (p < 0.36). CONCLUSION: All CT secondary signs of ureteral obstruction except nephromegaly showed a significant increase in frequency as duration of flank pain increased. This observation may explain why the CT studies of some patients with acute ureterolithiasis show negative findings for some or all CT secondary signs of obstruction. Therefore, knowledge of the duration of pain is important when interpreting unenhanced CT studies in patients with acute ureterolithiasis.

Sensitivity and value of digital CT scout radiography for detecting ureteral stones in patients with ureterolithiasis diagnosed on unenhanced CT.

OBJECTIVE: When unenhanced CT reveals ureterolithiasis, some patients will require baseline or follow-up conventional radiography to help guide clinical management. We sought to determine the sensitivity of routinely obtained scout radiographs for revealing stones to determine if the scout view can be used in place of baseline conventional radiography. MATERIALS AND METHODS: We retrospectively reviewed the CT scout radiographs in conjunction with axial CT images in a series of 215 consecutive patients in whom CT revealed a single ureteral stone. On the scout radiographs, stones were classified as definitely visible, definitely not visible, or indeterminate. In addition, a phantom was constructed using fragments of kidney stones to evaluate the effect of the digital scout kilovoltage settings on stone visualization. RESULTS: Forty-nine percent of stones were definitely visible on scout radiography, 47% were definitely not visible, and 4% were indeterminate. Four stones larger than 10 mm that were not visible on scout radiography were composed of uric acid (n = 2) or xanthine (n = 2). Scout radiographs of the phantom determined an optimal kilovoltage setting of 80-100 kVp to visualize stones less than 3 mm, whereas stones greater than or equal to 3 mm were visible at all kilovoltage settings. CONCLUSION: In our series, 49% of ureteral stones were visible on the often-overlooked routine CT scout radiograph. Imaging of phantoms showed that stone visualization can be optimized by using the lowest kilovoltage settings. Therefore, the CT scout view can be used as a baseline study in patients requiring follow-up radiography and for planning treatment of patients requiring lithotripsy or other intervention. Finally, large stones not visible on scout radiographs are likely composed of uric acid or xanthine.

Reexamining the value of hematuria testing in patients with acute flank pain.

PURPOSE: Hematuria testing is routinely performed in patients with acute flank pain to screen for ureterolithiasis and to help determine the need for excretory urography. Unenhanced helical computerized tomography (CT) has recently been shown to be superior to excretory urography in diagnosing ureteral obstruction and can evaluate many other causes of flank pain. Given the speed, accuracy and safety of CT the value of hematuria testing for acute flank pain should be reexamined. MATERIALS AND METHODS: We reviewed the medical records of 267 consecutive patients with acute flank pain referred for unenhanced helical CT. Microscopic and dipstick urinalysis data were obtained in 195 patients. Using helical CT as the gold standard, we calculated the sensitivity, specificity, predictive value and accuracy of hematuria for diagnosing ureterolithiasis. RESULTS: Of the patients with ureterolithiasis 33% had 5 or less, 19% had 1 or less and 11% had no red blood cells (RBCs) per high power field. Of the patients without ureterolithiasis 24% had greater than 5 and 51% had greater than 1 RBC per high power field. Of the patients with ureterolithiasis 14% had a negative dipstick test and 1 RBC or less per high power field. There were 25 patients without ureterolithiasis who had CT abnormalities unrelated to the urinary tract, of whom 8 had greater than 1 RBC per high power field. CONCLUSIONS: Absence of hematuria in the setting of acute flank pain cannot exclude a diagnosis of ureterolithiasis and should not obviate other diagnostic testing. Even when strongly positive on microscopy, hematuria has insufficient positive predictive value for diagnosing ureterolithiasis and may be misleading as other serious conditions resulting in acute flank pain may yield a positive test.

Acute flank pain: a modern approach to diagnosis and management.

Acute flank pain is a common and complex clinical problem. In addition to flank pain caused by ureterolithiasis, other urinary and extraurinary abnormalities can result in a similar clinical picture. Unenhanced CT can rapidly, accurately, and safely determine the presence or absence of ureteral obstruction. When obstruction is caused by ureterolithiasis, CT allows precise determination of stone size and location. These are the two most important factors used for patient management. In addition to direct stone visualization, there are many secondary CT signs of ureteral obstruction that are direct manifestations of the underlying pathophysiology. On the other hand, when obstruction is absent, CT can diagnose or exclude most other abnormalities that result in flank pain. As a result of its many advantages, unenhanced helical CT should become the dominant imaging modality for evaluation of all patients with acute flank pain in whom a clinical diagnosis is uncertain.

The value of unenhanced helical computerized tomography in the management of acute flank pain.

PURPOSE: We developed an algorithm using unenhanced computerized tomography (CT) for the management of acute flank pain and suspected ureteral obstruction. MATERIALS AND METHODS: During a 25-month interval 417 patients with acute flank pain underwent unenhanced helical CT. The final diagnosis was confirmed by additional imaging or clinical followup. For all patients who underwent additional imaging studies the official dictated radiology reports were used to determine whether the studies were recommended based on CT findings. Cases requiring intervention were evaluated to determine whether additional imaging was performed before the procedure. Medical records were reviewed and/or patients were interviewed to document the course of therapy and long-term outcome. RESULTS: Unenhanced helical CT diagnosed ureteral stone disease with 95% sensitivity, 98% specificity and 97% accuracy. Of the 38 patients requiring intervention, including nephrostomy catheters in 18, lithotripsy in 3 and ureteroscopic stone extraction in 7, additional imaging (excretory urography) was performed in only 1. Additional imaging studies generated by CT were done in 3 cases in which the dictated reports were indeterminate for ureteral stones, including negative excretory urography in 2 and retrograde urography in 1. In 1 patient in whom CT misdiagnosed a ureteral stone unnecessary retrograde urography revealed the calcification to be a gonadal vein phlebolith. Seven patients with false-negative examinations reported spontaneous stone passage with no complications. CONCLUSIONS: Unenhanced helical CT accurately determines the presence or absence of ureterolithiasis in patients with acute flank pain. CT precisely identifies stone size and location. When ureterolithiasis is absent, other causes of acute flank pain can be identified. In most cases additional imaging is not required.

Resuscitation of pulmonary contusion: hypertonic saline is not beneficial.

We postulated that hypertonic solutions could minimize the accumulation of lung water and subsequent respiratory derangements that occur after pulmonary contusion. Anesthetized pigs underwent contusion of the right chest at baseline and then were hemorrhaged (30 cc/kg) over 20 min. They were resuscitated with either 7.5% NaCl (4 cc/kg) or .9% saline (90 cc/kg) for 20 min and observed for 4 h. Gravimetric lung weights and spiral computed tomography scans were used to quantitate lung water. The hemodynamic response to contusion and hemorrhage was similar in both resuscitation groups. Arterial oxygen tension was not significantly altered by the method of resuscitation and remained close to baseline values for the entirety of the experiment. Static compliance measurements were significantly decreased from baseline in both groups following pulmonary contusion. There were no differences in wet to dry lung weights or computed tomography scan injury volume between groups. We conclude that small volume hypertonic saline resuscitation does not reduce the magnitude of lung injury or provide substantial physiologic benefit over isotonic solutions following pulmonary contusion.

Advances in the imaging of renal infection. Helical CT and modern coordinated imaging.

Traditionally, imaging of renal infections was largely through a multimodality approach. Excretory urography, ultrasonography, nuclear scintigraphy, and CT all played major roles; however, in recent years, CT has increased in prominence in the imaging and evaluation of renal infection. Part of the reason for this trend includes improvements in the availability of CT scanners and more timely access to them. Helical scanning technology has also greatly increased the quality and usefulness of the information CT provides. Most uncomplicated cases of acute renal infection in adults do not require imaging for diagnosis and treatment. When imaging is indicated, however, contrast-enhanced CT almost always is the study of choice. For cases in which renal calculi may be present, the study should also include noncontrast images through the kidneys.

Detection of choledocholithiasis: comparison of unenhanced helical CT and endoscopic retrograde cholangiopancreatography.

PURPOSE: To compare unenhanced helical computed tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP) in the detection of common bile duct calculi. MATERIALS AND METHODS: Within 13 months, 51 patients (aged 18-94 years) with clinically suspected choledocholithiasis underwent unenhanced helical CT immediately before undergoing ERCP. CT scans were evaluated for the presence of bile duct stones, ampullary stones, the gallbladder and gallbladder stones, intrahepatic biliary dilatation, and the size of the bile duct at the porta hepatis and in the pancreatic head. ERCP images were evaluated for the presence of bile duct or ampullary stones, as well as for biliary dilatation. RESULTS: Unenhanced helical CT depicted common bile duct stones in 15 of 17 patients found to have stones at ERCP. Three patients had stones impacted at the ampulla, all of which were detected with CT. In addition, there was one false-positive finding at CT. CT had a sensitivity of 88%, a specificity of 97%, and an accuracy of 94% in the diagnosis of common bile duct stones. CONCLUSION: Unenhanced helical CT is useful for evaluating suspected choledocholithiasis.

Soft-tissue "rim" sign in the diagnosis of ureteral calculi with use of unenhanced helical CT.

PURPOSE: To determine the value of the ureteric soft-tissue "rim" sign for differentiation of ureteral calculi from phleboliths on unenhanced helical computed tomographic (CT) scans and to identify factors that are associated with the presence of the rim sign. MATERIALS AND METHODS: Of 442 patients with ureteral obstruction confirmed at CT, 200 had documented ureteral stone disease; 136 of these patients had ureteral calculi, excluding the ureterovesical or ureteropelvic junctions. Each calculus and phlebolith along the course of the ureter were evaluated retrospectively and blindly for the presence of the rim sign, stone location, and stone size; the duration of symptoms was documented when available. RESULTS: The rim sign was present in 105 of 136 ureteral calculi (77%) and in 20 of 259 phleboliths (8%) and yielded a sensitivity of 77% and a specificity of 92% for distinguishing a calculus from a phlebolith. Calculi associated with the rim sign had a mean size of 4.3 mm, and calculi without a rim sign had a mean size of 6.3 mm (P < .001). There was no difference in duration of symptoms among patients who did or did not exhibit a rim sign. CONCLUSION: In patients with flank pain, the presence of a rim sign is a strong indicator that a calcification along the course of the ureter is a stone. Absence of the rim sign indicates that a calcification remains indeterminate.

Resuscitation of pulmonary contusion: effects of a red cell substitute.

OBJECTIVE: To determine the impact of a vasoactive red cell substitute, diaspirin cross-linked hemoglobin, on respiratory derangements after traumatic lung injury. DESIGN: Randomized, controlled animal experiment. SETTING: Large-animal laboratory. SUBJECTS: Mechanically ventilated, anesthetized young Yorkshire male swine (15 to 20 kg). INTERVENTIONS: Pigs (n = 6/group) received two pneumatic blasts to the right thoracic cage at baseline, were hemorrhaged 30 mL/kg from t = 0 to 20 mins, resuscitated with 0.9% saline (group 1, 90 mL/ kg) or diaspirin cross-linked hemoglobin (group 2, 15 mL/kg) from t = 20 to 40 mins, and then observed to t = 240 mins. MEASUREMENTS AND MAIN RESULTS: Serial pulmonary and systemic hemodynamic measurements, total thoracic compliance assessment, spiral three-dimensional computed tomography scan, and lung weights (n = 3/group) were used to assess lesion size and lung water. Mean arterial pressure was restored in both animal groups. Mean pulmonary arterial pressure was significantly higher after resuscitation in animals receiving the red cell substitute. Oxygenation worsened mildly in both groups. Compliance diminished in both groups but was significantly worse at the end of the experiment in animals infused with diaspirin cross-linked hemoglobin. Right lung weights and right thoracic computed tomography scan volume were higher with diaspirin cross-linked hemoglobin than with saline. CONCLUSIONS: After pulmonary contusion, resuscitation with diaspirin cross-linked hemoglobin led to pulmonary hypertension, greater pulmonary contusion lesion size, and stiffer lungs in this porcine model.

Acute ureteral obstruction: value of secondary signs of helical unenhanced CT.

OBJECTIVE: The purpose of our study was to determine the value of secondary signs of ureteral obstruction on helical unenhanced CT. MATERIALS AND METHODS: Over a 19-month interval, 312 patients with acute flank pain were imaged with helical unenhanced CT. Ureteral stone disease was confirmed to be present in 109 patients and confirmed to be absent in 111 patients Ninety-two remaining patients had no confirmatory imaging studies or surgery and were unable to be contacted for follow-up. For each of the 220 patients with a confirmed diagnosis, we determined the presence or absence of ureteral or collecting system dilatation, perinephric stranding, symmetry of renal size, and renal stones. In all patients with a ureteral stone, we noted the presence or absence of a circumferential rim of soft-tissue attenuation ("tissue-rim" sign) surrounding each stone and each phlebolith. RESULTS: The sensitivity of each secondary sign was ureteral dilatation, 90%; perinephric stranding, 82%; collecting system dilatation, 83%; and renal enlargement, 71%. The specificity of each secondary sign was ureteral dilatation, 93%; perinephric stranding, 93%; collecting system dilatation, 94%; and renal enlargement, 89%. Ureteral dilatation and perinephric stranding were both present or both absent in 181 of the 220 patients with a confirmed diagnosis. In this subgroup, this combination of signs had a positive predictive value of 99% and a negative predictive value of 95%. The odds ratio for the frequency of the tissue-rim sign with stones versus tissue-rim with phleboliths was 31:1. CONCLUSION: When using unenhanced CT to help diagnose acute flank pain, if one does not see a ureteral stone or does see an indeterminate but suspicious calcification, then secondary signs of obstruction are important for diagnosis. The results of this study form the basis of an imaging algorithm that can be used when interpreting unenhanced CT images of patients with acute flank pain.

CT urography in the evaluation of urinary tract disease.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of using limited CT through the kidneys following excretory urography in selected situations. MATERIALS AND METHODS: Within 2 h of excretory urography 568 patients had add-on CT without using additional contrast medium. In 487 patients with hematuria the results of the combined studies were compared with blinded prospective interpretations of each. In addition 81 patients had add-on CT for specific urographic questions. RESULTS: Of the 345 renal parenchymal masses seen on CT in both groups, only 185 were detected prospectively on excretory urography. For the 81 patients who had CT because of abnormalities seen on excretory urography, including 54 with pseudotumors, findings were clarified and the correct diagnosis made. In 27 of 30 patients with lesions in the collecting system the lesions were detected only on excretory urography. CONCLUSION: Excretory urography followed by limited CT increases the diagnostic accuracy for detecting, characterizing, or ruling out urinary tract disease by combining the high sensitivity of traditional excretory urography for detecting lesions in the collecting system and ureter with the high accuracy of CT for parenchymal and perinephric lesions without an additional patient visit or additional contrast medium. Because it leaves so few unanswered questions, the combination of standard excretory urography and limited CT is an excellent screening study in selected situations. It can be performed quickly, at controlled cost, is highly accurate, and is convenient for the patient, the referring physician, and the examining department.

Diagnosis of acute flank pain: value of unenhanced helical CT.

OBJECTIVES: The purpose of our study was to determine the value of unenhanced CT in the diagnosis of acute flank pain. We determined the accuracy of unenhanced Ct for stone detection as well as the detection of abnormalities unrelated to stone disease. MATERIALS AND METHODS: During an 18-month interval, 292 patients with acute flank pain were imaged with unenhanced CT. Confirmation of the CT diagnosis was obtained for 210 patients: One hundred patients were proved to have ureteral stones based on other imaging studies (58 patients), lithotripsy (seven patients), ureteroscopic stone extraction (five patients), and stone recovery (30 patients). One hundred ten patients were proved not to have ureteral stones based on other imaging studies (24 patients), failure to recover a stone (56 patients), or a confirmed diagnosis unrelated to stone disease (30 patients). This latter group of 30 patients included diagnoses of adnexal masses (eight patients), appendicitis (five patients), diverticulitis (four patients), and common bile duct stones (three patients), as well as other diagnoses. RESULTS: Unenhanced CT findings were falsely negative for stone disease in three patients and falsely positive for stone disease in four patients. These data yield a sensitivity of 97%, a specificity of 96%, and an accuracy of 97% for diagnosing ureteral stone disease. Of 31 patients with a CT abnormality unrelated to stone disease, there was one false-negative diagnosis of acute appendicitis. CONCLUSION: Unenhanced CT is a valuable technique for examining patients with acute flank pain in whom a clinical diagnosis is uncertain. It can accurately determine the presence or absence of ureteral stones as well as extraurinary causes of acute flank pain. In most cases, other imaging studies are not required.

Acute flank pain: comparison of non-contrast-enhanced CT and intravenous urography.

PURPOSE: To compare non-contrast-enhanced computed tomography (CT) and intravenous urography (IVU) in the evaluation of patients who present with acute flank pain and in whom ureteric obstruction is suspected. MATERIALS AND METHODS: The findings at non-contrast-enhanced CT and IVU in 20 patients with acute flank pain were compared for the presence or absence of ureteric obstruction and delineation of ureteric stones. RESULTS: Twelve of the 20 patients had non-contrast-enhanced CT and IVU findings consistent with ureteric obstruction. Of these 12 patients, five had a ureteric stone that was demonstrated on both non-contrast-enhanced CT scans and IVU radiographs, six had a stone that was depicted on non-contrast-enhanced CT scans only, and in one patient a stone could not be delineated definitively on either non-contrast-enhanced CT scans or IVU radiographs. Eight patients had findings at non-contrast-enhanced CT and IVU consistent with the absence of obstruction. CONCLUSION: Non-contrast-enhanced CT is more effective than IVU in precisely identifying ureteric stones and is equally effective as IVU in the determination of the presence or absence of ureteric obstruction.

Preoperative abdominopelvic computed tomographic prediction of optimal cytoreduction in epithelial ovarian carcinoma.

PURPOSE: This study was undertaken to assess the ability of computed tomography (CT) to predict the likelihood of optimal primary tumor cytoreduction in women with epithelial ovarian carcinoma. PATIENTS AND METHODS: Fifty-one women with preoperative CT and a histologic diagnosis of epithelial ovarian carcinoma following primary tumor operation by a gynecologic oncologist were identified. Forty-two CT scans were retrospectively analyzed. CT findings of attachment of the omentum to the spleen or disease greater than 2 cm on the diaphragm, liver surface, or parenchyma, pleura, mesentery, gallbladder fossa, or suprarenal paraaortic nodes were coded to represent unresectable disease. CT results were compared with surgical outcome. RESULTS: Twenty-nine of 42 (69%) patients underwent optimal cytoreduction to less than 2 cm residual disease. Successful cytoreduction was accomplished in 23 of 24 patients who fulfilled CT criteria for cytoreduction and six of 18 with CT criteria predictive of inability to perform cytoreduction. CT was highly sensitive for detection of ascites, mesenteric, and omental disease, but was poor for detection of liver involvement, omental attachment to the spleen, gallbladder fossa disease, and peritoneal nodules smaller than 2 cm. The CT findings accurately predicted surgical outcome with a sensitivity of 92.3% and specificity of 79.3%. The positive predictive value was 67% and the negative predictive value was 96%. CONCLUSION: CT scan is an accurate method for the prediction of successful surgical cytoreduction and may have utility in the decision to offer neoadjuvant chemotherapy to certain medically disabled patients, a hypothesis currently under evaluation.