Small-bowel diseases: prospective evaluation of multi-detector row helical CT enteroclysis in 107 consecutive patients

PURPOSE: To prospectively evaluate multi-detector row helical computed tomographic (CT) enteroclysis for the depiction of small-bowel diseases. MATERIALS AND METHODS: The study group included 107 patients who were suspected of having small-bowel tumor (n = 8), active inflammatory small-bowel disease (n = 18), unexplained gastrointestinal bleeding (n = 36), refractory celiac sprue (n = 14), and low-grade small-bowel obstruction (n = 31). A nasoenteric tube was positioned into the duodenojejunal junction by using fluoroscopic guidance and water was infused with a pressure-controlled pump. After intravenous administration of 120 mL of iodinated contrast material, multi-detector row helical CT enteroclysis images were obtained with 4 x 2.5 mm collimation (four detector rows and 2.5-mm section thickness). Multi-detector row helical CT enteroclysis findings were analyzed by two readers working in consensus. Findings were compared with the results of endoscopy, enteroscopy, videocapsule endoscopy, histopathologic analysis, or clinical follow-up. RESULTS: Multi-detector row helical CT enteroclysis was well tolerated in 106 patients; one patient complained of abdominal pain after the examination. Multi-detector row helical CT enteroclysis allowed the diagnosis of small-bowel masses (n = 21), active Crohn disease (n = 9), small-bowel tuberculosis (n = 2), small-bowel lymphoma complicating celiac disease (n = 4), and confirmed low-grade small-bowel obstruction (n = 12). Multi-detector row helical CT enteroclysis demonstrated normal findings in 60 patients. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of multi-detector row helical CT enteroclysis were 100%, 95%, 97%, 94%, and 100%, respectively. CONCLUSION: Multi-detector row helical CT enteroclysis allows depiction of small-bowel diseases in patients suspected of having small-bowel conditions.     

口服法小肠灌肠CT检查的诊断价值研究

目的：评价口服法小肠灌肠CT检查对小肠病变的诊断价值。材料和方法：研究的对象包括2003年1月-2005年3月间53例临床怀疑有小肠病变而行小肠CT检查的患者。扫描前20—30rain口服混合溶液（每1000ml由20％甘露醇250ml＋5％糖盐水500ml＋水250ml所配成）约2000ml充盈小肠。首先，对小肠的扩张程度进行评价；其次，通过横断位及多平面重建，从局限性或弥漫性肠壁增厚、小肠肿块、小肠系膜扭转、肠系膜淋巴结肿大、远处转移几方面进行征象分析，并作出诊断。分别计算小肠CT检查的敏感度、特异度、阳性预测值和阴性预测值。结果：小肠扩张最佳的24例（24／53），扩张良好的25例（25／53），扩张欠佳的4例（4／53），无扩张0例（0／53）；口服肠道准备小肠CT检查的敏感度为97．6％（40／41），特异度为75％（9／12），阳性预测值为93．0％（40／43），阴性预测值为90．0％（9／10）。结论：口服肠道准备小肠螺旋CT检查方能够很好满足诊断需要，对小肠病变具有诊断价值。     

Acute massive gastrointestinal bleeding: detection and localization with arterial phase multi-detector row helical CT

PURPOSE: To prospectively evaluate accuracy of arterial phase multi-detector row helical computed tomography (CT) for detection and localization of acute massive gastrointestinal (GI) bleeding, with angiography as reference standard. MATERIALS AND METHODS: Institutional review board approved this study; written informed consent was obtained from each patient or patient's family after procedures, including radiation dose, were explained. Twenty-six consecutive patients (17 men, nine women; age range, 18-89 years) had acute massive GI bleeding (defined as requirement of transfusion of at least 4 units of blood during 24 hours in the hospital or as hypotension with systolic blood pressure <90 mm Hg) and underwent arterial phase multi-detector row CT before angiography. Scans were obtained during arterial phase to identify extravasation of contrast material with attenuation greater than 90 HU within bowel lumen; this finding was considered diagnostic for active GI bleeding. Presence of contrast medium extravasation in each anatomic location was recorded. Sensitivity, specificity, positive and negative predictive values, and accuracy of multi-detector row CT for detection of acute GI bleeding were assessed. Accuracy for localization of acute GI bleeding was assessed by comparing locations of active bleeding at both multi-detector row CT and angiography in each patient who had active bleeding. RESULTS: Arterial phase multi-detector row CT depicted extravasation of contrast material in 21 of 26 patients. Overall location-based sensitivity, specificity, accuracy, and positive and negative predictive values of multi-detector row CT for detection of GI bleeding were 90.9% (20 of 22), 99% (107 of 108), 97.6% (127 of 130), 95% (20 of 21), and 98% (107 of 109), respectively. Overall patient-based accuracy of multi-detector row CT for detection of acute GI bleeding was 88.5% (23 of 26). The location of contrast material extravasation on multi-detector row CT scans corresponded exactly to that of active bleeding on angiograms in all patients with contrast medium extravasation at both multi-detector row CT and angiography. CONCLUSION: Arterial phase multi-detector row CT is accurate for detection and localization of bleeding sites in patients with acute massive GI bleeding.     

Pancreas divisum: depiction with multi-detector row CT

PURPOSE: To retrospectively evaluate contrast material-enhanced multi-detector row computed tomography (CT) in the depiction of pancreas divisum. MATERIALS AND METHODS: This study was approved by the investigational review board. Seventy-seven patients (46 men and 31 women; mean age, 51 years) underwent CT with a four-detector row scanner and endoscopic retrograde pancreatography (ERP). Section thickness was 3.2 mm, and the reconstruction interval was 3 mm. Two radiologists independently evaluated the CT data sets with picture archiving and communication system (PACS) workstations equipped with software for two- and three-dimensional postprocessing reformations; the radiologists were blinded to the clinical and ERP data. Pancreas divisum was diagnosed at CT if what the authors termed the "dominant dorsal duct sign" (the caliber of the dorsal duct was larger than that of the ventral duct) was present and if the dorsal and ventral ducts did not appear to communicate with each other at cine review of images. ERP findings were used as the standard of reference for determining the performance (sensitivity, specificity, positive and negative predictive values) of the radiologists' CT interpretations. Interobserver agreement was measured by using kappa statistics. RESULTS: For four of the 77 patients (5%), both radiologists considered that depiction of the pancreatic duct on CT images was not sufficient to enable evaluation of ductal anatomy. These patients were excluded from further analysis. In the remaining 73 patients, ERP demonstrated pancreas divisum in 10 (14%); both observers made the correct diagnosis in nine of these patients. In addition, one radiologist had one false-positive interpretation, whereas the other radiologist had two false-positive interpretations. Thus, for observer 1, the calculated sensitivity was 90% (95% confidence interval [CI], 60%-98%) and the specificity was 98% (95% CI, 91%-100%). For observer 2, sensitivity was 90% (95% CI, 60%-98%) and specificity was 97% (95% CI, 89%-99%). Interobserver agreement was excellent (kappa = 0.93). CONCLUSION: CT scans obtained with multi-detector row scanners and interpreted with PACS workstations enable depiction of pancreas divisum. This assessment is possible only when the pancreatic duct is visualized.     

CT colonography: single- versus multi-detector row imaging

PURPOSE: To compare respiratory artifacts, colonic distention, and polyp detection at computed tomographic (CT) colonography by using single- and multi-detector row helical CT systems. MATERIALS AND METHODS: A total of 237 consecutive patients received subcutaneously administered glucagon and underwent prone and supine CT colonography with single-detector row CT (n = 77) and multi-detector row CT (n = 160), followed by colonoscopy. Examination results were graded for colonic distention, respiratory artifacts, and polyp depiction by two radiologists working independently. RESULTS: Suboptimal colonic distention was significantly more common with single-detector row CT and was present in at least one segment in 52% (40 of 77 patients) of examinations versus only 19% (30 of 160 patients) with multi-detector row CT (P <.001). Mild respiratory artifacts were present in 61% (47 of 77 patients) of single-detector row CT examinations versus only 16% (26 of 160 patients) of multi-detector row CT examinations (P <.001). Depiction of polyps larger than 10 mm was 89% (eight of nine polyps) for single-detector row CT and 80% (eight of 10 polyps) for multi-detector row CT (P >.05). CONCLUSION: CT colonography performed with multi-detector row CT significantly improved the demonstration of colonic distention and depicted fewer respiratory artifacts compared with single-detector row CT. No significant differences in the depiction of polyps larger than 10 mm were demonstrated between single- and multi-detector row CT for a small number of polyps. Studies with a larger prevalence of clinically important polyps are needed for further evaluation of differences in polyp detection.     

Orthopedic hardware complications diagnosed with multi-detector row CT

PURPOSE: To retrospectively evaluate multi-detector row computed tomography (CT) for the depiction of orthopedic hardware complications in the spine and appendicular skeleton. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval; patient informed consent was not required. Results of 114 multi-detector row CT studies performed because of possible hardware complications in 109 patients (57 men, 52 women; mean age, 44 years; age range, 12-82 years) were available for analysis. The CT studies were retrospectively reviewed and compared with clinical or surgical outcomes, which were used as the reference standard. In another experiment, detection of hardware complications on radiographs and multi-detector row CT images was compared between two readers for selected cases (18 positive and 26 negative) by using receiver operating characteristic (ROC) methods. RESULTS: For 91 (80%) of 114 multi-detector row CT studies, the complication status could be determined on the basis of clinical or surgical outcomes. Twenty-three multi-detector row CT studies were confirmed to be positive (revealing 10 cases of nonunion, five cases of hardware malplacement, three cases of hardware loosening, three perihardware fractures, and two chronic infections), and 57 were confirmed to be negative. There were three false-positive and eight false-negative multi-detector row CT studies. With clinical or surgical outcomes as the reference standard, the sensitivity, specificity, and positive and negative predictive values of multi-detector row CT were 74% (23 of 31 studies), 95% (57 of 60 studies), 88% (23 of 26 studies), and 88% (57 of 65 studies), respectively. Results of ROC analysis indicated that detection of hardware complications was much lower with radiography than with multi-detector row CT (area under ROC curve, 0.84 vs 1.00; F = 4.69, df = 1, 43; P < .05). CONCLUSION: Multi-detector row CT is an effective tool for depicting orthopedic hardware complications.     

Multi-detector row CT of mesenteric ischemia: can it be done?

Mesenteric ischemia is a complicated disorder whose prevalence in the United States is increasing as the population ages. It is often difficult to diagnose, both clinically and radiologically. In the past, computed tomography (CT) has allowed only limited success in the early detection of ischemia. However, with the introduction of multi-detector row CT and three-dimensional (3D) imaging, it is now possible to perform a detailed CT examination of the small bowel and mesenteric vessels. Multi-detector row CT allows routine studies to be performed much faster than with single-detector CT scanners and makes available new applications, especially in the field of CT angiography. Its increased speed and narrower collimation, coupled with the use of water as an oral contrast agent, improve visualization of the bowel wall and mesenteric vasculature. Multi-detector row CT with 3D reformatting may improve the ability to make an early diagnosis and identify the cause of disease in patients with suspected acute or chronic mesenteric ischemia. In many cases, this examination has eliminated the need for additional imaging studies such as Doppler ultrasonography or angiography. Further investigation will be needed to determine the scope of the utility of multi-detector row CT in this clinical setting.     

Volume-rendered 3D CT of the mesenteric vasculature: normal anatomy, anatomic variants, and pathologic conditions.

Multi-detector row computed tomography (CT) offers important advantages over more conventional imaging methods in the evaluation of the mesenteric vasculature. It allows faster scanning, which practically eliminates motion and breathing artifacts, as well as thinner collimation. These advances, coupled with rapid intravenous administration of contrast material, allow excellent opacification of the mesenteric arteries and veins. This improves the quality of the three-dimensional (3D) data sets, which in turn leads to improved 3D vascular maps and more accurate assessment of various conditions such as arterial or venous encasement in patients with pancreatic cancer, mesenteric ischemia, or inflammatory bowel disease. Three-dimensional multi-detector row CT also allows better visualization of arterial and venous branching, thereby improving detection of more distal vascular involvement. In addition, 3D multi-detector row CT may help detect hemodynamic changes in patients with active inflammation and hyperemia of a bowel segment because it can be used to measure bowel wall enhancement over time. Carcinoid tumors that have infiltrated the mesentery have a characteristic CT appearance, and other conditions such as lymphoma or sclerosing mesenteritis can also manifest as an infiltrating mass that envelops mesenteric vessels. Three-dimensional multi-detector row CT represents a significant advance in CT technology and can help ensure prompt, accurate evaluation of the mesenteric vasculature.     

Role of computerized tomography in the diagnosis of peritoneo-intestinal lesions resulting from closed trauma. Experience at 2 emergency departments

INTRODUCTION: Small and large bowel mesenteric injuries from blunt abdominal trauma are rare and often difficult to diagnose. Computed Tomography used in cases of blunt abdominal trauma has been found sensitive in detection of bowel and mesenteric injuries and discrimination of operable from nonoperable candidates. PURPOSE: A retrospective study of the CT examination of 24 patients, with surgically confirmed bowel and mesenteric injuries, was performed. Our goal was to evaluate the various CT signs of blunt bowel and mesenteric injury and the related frequency. MATERIAL AND METHODS: Our series includes 24 patients, 16 of them (first group) were investigated with CT at Cardarelli Hospital, Naples, while the remaining 8 (second group) at University of Bari. Patients of the first group, 11 men and 5 women, age ranging from 18 to 77 years, were submitted to a conventional abdominal CT performed after i.v. administration of contrast media. Patients of the second group, 7 men and 1 woman, age ranging from 4 to 81 years, were submitted to helical CT performed with the following parameters: 10 mm slice thickness, 5-mm contiguous intervals from the level of the diaphragm to the pubic bone, pitch 1.5. Helical CT was performed in all cases before and after i.v. administration of contrast material injected at a rate of 3.5 ml/sec. A scanning delay of 40 seconds after the beginning of contrast injection was routinely used. In all patients the following CT signs were retrospectively searched on: peritoneal or retroperitoneal fluid, mesenteric hematoma, hazy streaky changes in mesenteric fat, high-density clot (sentinel clot) adjacent to the involved bowel, pneumoperitoneum, retropneumoperitoneum, extravasation of intravenous contrast material, bowel wall thickening. RESULTS: In the first group the following CT signs were observed: mesenteric hematoma (87.5%), hazy streaky changes in mesenteric fat (56.25%), peritoneal or retroperitoneal fluid (37.5%), sentinel clot (25%), bowel wall thickening (18.75%), extravasation of intravenous contrast material (12.5%). In the second group the following CT signs were observed: peritoneal or retroperitoneal fluid (87.5%), bowel wall thickening (50%), mesenteric hematoma (37.5%), sentinel clot (25%), pneumoperitoneum (12.5%), retropneumoperitoneum (12.5%), hazy streaky changes in mesenteric fat (12.5%). DISCUSSION AND CONCLUSIONS: Bowel and mesenteric injuries from blunt trauma are infrequent and difficult to diagnose clinically, as the physical and laboratory findings may be subtle and are often overshadowed by other injuries in patients with multisystem trauma. CT represents a proven modality in the evaluation of bowel and mesenteric injuries: careful inspection and technique are required to detect often subtle findings. In our series of 24 patients with surgically confirmed bowel and mesenteric injuries, the presence of mesenteric hematoma and of peritoneal or retroperitoneal fluid were the more frequent CT signs observed. Radiologists may play a crucial role in the timely diagnosis of these injuries, allowing prompt and appropriate management of these patients.     

Interosseous ligament tears of the wrist: comparison of multi-detector row CT arthrography and MR imaging

PURPOSE: To compare the accuracy of multi-detector row computed tomographic (CT) arthrography and magnetic resonance (MR) imaging in depicting tears of dorsal, central, and palmar segments of scapholunate (SL) and lunotriquetral (LT) ligaments in cadavers. MATERIALS AND METHODS: Cadaver wrists were obtained and used according to institutional guidelines and with informed consent of donors prior to death. Nine cadaver wrists of eight subjects were evaluated. MR images were obtained with a 1.5-T MR unit. Imaging protocol included intermediate-weighted coronal and transverse fast spin-echo and coronal three-dimensional gradient-echo sequences. Multi-detector row CT arthrography was performed after tricompartmental injection of 3-6 mL of contrast material with a concentration of 160 mg per milliliter of iodine. Palmar, dorsal, and central segments of both ligaments were analyzed on transverse and coronal MR images and multiplanar multi-detector row CT reconstructions by two musculoskeletal radiologists working independently. Open inspection of the wrists was the reference standard. Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated from the imaging and gross pathologic readings. Statistical significance was calculated with the McNemar test. Weighted kappa values for interobserver agreement were calculated for both imaging modalities. RESULTS: All ligament segments could be visualized in all cases with both imaging modalities. CT arthrography was more sensitive (100%) than MR imaging (60%) in detection of palmar segment tears (P = .62); specificity of both imaging modalities was 77%. Sensitivity (CT arthrography, 86%; MR imaging, 79%) and specificity (CT arthrography, 50%; MR imaging, 25%) for detection of the central segment tears were determined. Dorsal segment tears were detected only with CT arthrography, while all tears were missed with MR imaging (P = .02). Interobserver agreement was better for multi-detector row CT arthrography (kappa = 0.37-0.78) than for MR imaging (kappa = -0.33 to -0.10). CONCLUSION: Performance in depiction of palmar and central segment tears of SL and LT ligaments is almost equal for multi-detector row CT arthrography and MR imaging, with much higher interobserver reliability for CT arthrography. CT arthrography is significantly superior to MR imaging in the detection of dorsal segment tears of SL and LT ligaments.     

Bowel and mesenteric injury following blunt abdominal trauma: evaluation with CT

Computed tomography (CT) used in cases of blunt abdominal trauma has been found sensitive in detection of bowel and mesenteric injuries and discrimination of operable from nonoperable candidates. In 51 patients with suspected bowel or mesenteric injury following blunt abdominal trauma, CT correctly depicted bowel hematoma or mesenteric injury in 17 of 19 nonoperable patients (89%) and severe injuries in one patient who died preoperatively. In 26 of 28 patients who underwent therapeutic laparotomy (93%), initial CT enabled identification of surgically confirmed injuries. In two cases, initial scan misinterpretation delayed diagnosis of serious bowel injuries. The correct interpretation was rendered preoperatively and at blind retrospective review. CT findings that correlated with bowel or mesenteric injury requiring surgery were free peritoneal fluid (27 of 28, 96%), mesenteric infiltration (24 of 28, 86%), thick-walled bowel (17 of 28, 61%), associated abdominal injuries (12 of 28, 43%), and free air (nine of 28, 32%). In nonoperable cases, CT scans demonstrated bowel thickening (84%) but less frequently peritoneal fluid (21%), mesenteric infiltration (26%), or associated injuries (5%). In three of four patients who underwent nontherapeutic laparotomy, preoperative CT correctly imaged the limited abdominal injuries.     

Diagnosis of acute pulmonary embolism in outpatients: comparison of thin-collimation multi-detector row spiral CT and planar ventilation-perfusion scintigraphy

PURPOSE: To compare multi-detector row computed tomography (CT) and ventilation-perfusion (V-P) scintigraphy in the diagnosis of acute pulmonary embolism (PE) in outpatients who were cared for in the emergency department. MATERIALS AND METHODS: Ninety-four nonconsecutive patients, in whom acute PE was suspected, underwent thin-collimation multi-detector row CT (collimation, 4 x 1 mm; pitch, 1.25; scanning time, 0.5 second) and V-P scintigraphy. Concordance between CT and scintigraphic images was used in the diagnosis of PE. Pulmonary angiography was performed within 24 hours if interpretations of V-P and spiral CT images were inconclusive or discordant. Sensitivity and specificity values were calculated for V-P scintigrams and CT scans of the lungs. The rates of conclusive results for scintigraphy and CT were compared. RESULTS: The sensitivity of thin-collimation multi-detector row CT and V-P scintigraphy for the detection of PE was 96% (27 of 28; CI: 82%, 99%) and 98% (65 of 66; CI: 92%, 99%), respectively. The specificity of CT and V-P scintigraphy was 86% (24 of 28; CI: 67%, 96%) and 88% (58 of 66; CI: 77%, 94%), respectively. Seven V-P scintigrams were of intermediate probability, and one spiral CT study was indeterminate. Examinations with spiral CT yielded conclusive results more often than examinations with planar V-P scintigraphy (P <.05). Five V-P scintigrams and spiral CT scans were discordant. Twelve pulmonary angiographic examinations were performed. Angiographic findings were concordant in 10 (91%) of 11 patients with conclusive CT scans in whom pulmonary angiography was attempted. CT was used to establish an alternative diagnosis in 19 (29%) of 66 patients in whom PE was excluded. CONCLUSION: Thin-collimation multi-detector row CT is more accurate than V-P scintigraphy in the diagnosis of acute PE in outpatients. Furthermore, CT provides alternative diagnoses for patients without PE on high-quality transverse or near-isotropic reformatted images.     

Diagnostic performance of helical CT angiography in trauma to large arteries of the extremities

PURPOSE: The purpose of this work was to assess the performance of helical CT angiography (CTA) in the diagnosis of injuries to large arteries of the extremities. METHOD: We performed helical CTA on 45 consecutive patients referred for conventional angiography for evaluation of suspected arterial injuries after sustaining trauma to the extremities (13 upper, 32 lower). Two radiologists interpreted the helical CTA studies independently. Diagnostic performance parameters evaluated included sensitivity, specificity, receiver operating characteristic (ROC) curves, and interobserver agreement (kappa statistics). Conventional angiography was used as the standard of reference for determination of final diagnoses. RESULTS: Forty-three of 45 patients (96%) had diagnostic helical CTA examinations. Final diagnoses in these 43 patients were arterial occlusion (n = 7), partial obstruction (n = 3), pseudoaneurysm (n = 5), arteriovenous fistula (n = 1), pseudoaneurysm and arteriovenous fistula (n = 3), and normal findings (n = 24). Sensitivity and specificity were 90% [95% confidence interval (CI), 80-99] and 100% (95% CI, 99-100), respectively, for Reader 1 and 100% (95% CI, 99-100) and 100% (95% CI, 99-100), respectively, for Reader 2. ROC curve analysis revealed high diagnostic performance, with areas under the curve of >0.9 for both readers. Interobserver agreement was 0.9. CONCLUSION: The diagnostic performance of helical CTA for detection of major injuries of large arteries of the extremities is high.     

Blunt trauma to the gastrointestinal tract and mesentery: is there a role for helical CT in the decision-making process?

The CT diagnosis of bowel and mesenteric injuries is difficult and warrants optimal technique and skilled interpretation. We retrospectively reviewed 36 consecutive patients with blunt traumatic injuries to the bowel and mesentery at our regional level I trauma center during the past 3 years. Physical examination, laboratory, Computed tomographic (CT), and intraoperative findings were compared. Surgically proven bowel injuries (13 cases) occurred in the duodenum (three cases), ileum (two cases), jejunum (two cases), colon (three cases), and stomach (three cases). CT findings considered specific of bowel rupture were observed in 5/13 patients including: extraluminal oral contrast or luminal content extravasation (four cases) and discontinuity of hollow viscus wall (one case). In the remaining 8/13 CT findings considered suggestive of bowel injury consisted of: pneumoperitoneum (six), gas bubbles close to the injured hollow viscus (three), thickened (>4-5mm) bowel wall (five), bowel wall hematoma (three), intraperitoneal fluid of unknown source (three). Mesenteric injury (23 cases) were surgically observed at the level of the mesenteric vessels (17 cases), legament of Treitz (two cases), gastro-duodenal artery (one case), transverse (one case) and sigmoid mesocolon (one case). CT finding considered specific of mesenteric laceration was active extravasation of contrast material from the mesenteric vessels (10 cases). CT findings suggestive of mesenteric injury (13 cases) consisted of: mesenteric hematoma (five) and/or high attenuation fluid collections, within the mesenteric root (eight) and folds (four). Helical CT is sensitive in the identification of bowel and mesenteric injury after blunt trauma providing a wide spectrum of findings. However, CT cannot be used as the sole indicator in cases with isolated thichened bowel wall, mesenteric hematoma, bowel hematoma, pneumoperitoneum or gas bubbles. Persistent, active extravasation of intravenous constrast medium from the mesenteric vessels, in isolation or associated with further injuries, requires immediate exploration and repair; disruption of bowel wall and extravasation of oral contrast are definite signs of bowel rupture. Close clinical observation, monitoring, and surgical expertise are mandatory for appropriate management.     

Does multi-detector row CT pulmonary angiography reduce the incremental value of indirect CT venography compared with single-detector row CT pulmonary angiography?

PURPOSE: To compare retrospectively the incremental value of indirect computed tomographic (CT) venography performed after multi-detector row CT pulmonary angiography and single-detector row CT pulmonary angiography for the diagnosis of venous thromboembolism (VTE). MATERIALS AND METHODS: The institutional ethics committee approved this study; informed consent was not required. The authors retrospectively reviewed results of 1100 combined single-detector row CT pulmonary angiographic and indirect CT venographic examinations (542 men, 558 women; mean age, 61 years +/- 17 [standard deviation]) (group 1) and 308 combined multi-detector row CT pulmonary angiographic and indirect CT venographic examinations (150 men, 158 women; mean age, 62 years +/- 18) (group 2), performed in 1408 patients suspected of having pulmonary embolism (PE). Frequency of deep venous thrombosis (DVT), PE, and VTE, and the incremental value of indirect CT venography were recorded in both groups. Data were compared by means of the Student t test for continuous data and z statistics for independent proportions. RESULTS: VTE, PE, and DVT were found in 23.3% (n = 256), 19.9% (n = 219), and 18.3% (n = 201) of the 1100 patients in group 1, respectively, and in 23.7% (n = 73), 17.2% (n = 53), and 18.8% (n = 58) of the 308 patients in group 2, respectively (P values ranging from .273 to .876). The incremental value of indirect CT venography was 14.4% (37 of 256 patients) in group 1 and 27.4% (20 of 73 patients) in group 2. CONCLUSION: Despite potential improved accuracy of multi-detector row CT pulmonary angiography for the diagnosis of PE, the addition of indirect CT venography increased the diagnosis of VTE in 27.4% of patients.     

Exclusion of unstable cervical spine injury in obtunded patients with blunt trauma: is MR imaging needed when multi-detector row CT findings are normal?

PURPOSE: To retrospectively determine what information, if any, magnetic resonance (MR) imaging of the cervical spine in obtunded and/or "unreliable" patients with blunt trauma adds to multi-detector row computed tomography (CT) of the entire cervical spine (including routine multiplanar sagittal and coronal reformations) when the CT findings are normal. MATERIALS AND METHODS: The study was HIPAA compliant and institutional review board approved. Informed consent was not required. From April 2001 to November 2003, 1400 trauma patients underwent MR imaging of the cervical spine to evaluate potential cervical spine injuries. Multi-detector row CT of the cervical spine was performed with a four- or 16-detector row scanner. MR imaging of the cervical spine was performed with transverse gradient-echo, sagittal intermediate-weighted, sagittal short inversion time inversion-recovery, and sagittal T1- and T2-weighted fast spin-echo sequences. Many MR examinations were performed to exclude soft-tissue injuries in the cervical spine of obtunded patients with blunt trauma in whom cervical spine injury could not be excluded with physical examination. Complete cervical spine MR studies were obtained to evaluate soft-tissue injuries in 366 obtunded patients with blunt trauma (281 male and 85 female patients; age range, 13-92 years; mean age, 42.1 years). The patients had previously undergone total cervical spine multi-detector row CT with normal findings. The results obtained with these two modalities were compared. RESULTS: MR images were negative for acute injury in 354 of the 366 patients and negative for cervical spine ligamentous injury in 362. Seven of the 366 patients had cervical cord contusions, four patients had ligamentous injuries, three patients had intervertebral disk edema, and one patient had a cord contusion, a ligamentous injury, and an intervertebral disk injury. Four patients had ligamentous injuries; however, all of these patients had ligament injuries limited to only one of the three columns of cervical spine ligament support. Multi-detector row CT had negative predictive values of 98.9% (362 of 366 patients) for ligament injury and 100% (366 of 366 patients) for unstable cervical spine injury. CONCLUSION: A normal multi-detector row CT scan of the total cervical spine in obtunded and/or "unreliable" patients with blunt trauma enabled the authors to exclude unstable injuries on the basis of findings at follow-up cervical spine MR imaging.     

Possible small-bowel neoplasms: contrast-enhanced and water-enhanced multidetector CT enteroclysis

PURPOSE: To prospectively evaluate the sensitivity and specificity of contrast material-enhanced and water-enhanced multidetector computed tomographic (CT) enteroclysis in depicting small-bowel neoplasms in symptomatic patients, with endoscopic, tissue, and follow-up findings as reference standards. MATERIALS AND METHODS: The study protocol was approved by the Human Research Committee of the institution, and all patients gave written informed consent. Two hundred nineteen patients (108 male, 111 female; age range, 17-98 years; mean, 53.1 years) with clinical suspicion of small-bowel neoplasm underwent contrast- and water-enhanced multidetector CT enteroclysis after normal findings of upper and lower gastrointestinal endoscopy. The prospective interpretations of CT enteroclysis results include evaluation of focal bowel wall thickening, small-bowel masses, small-bowel stenosis, mesenteric stranding, enlarged mesenteric lymph nodes, and visceral metastasis. Positive enteroclysis findings were compared with results of pathologic examination after surgical (n = 35) or endoscopic (n = 20) procedures. Negative results were compared with results of surgery (n = 8), enteroscopy (n = 15), capsule endoscopy (n = 14), and clinical follow-up (n = 127). Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated on a per-patient basis with 95% confidence intervals. RESULTS: Findings of CT enteroclysis were positive in 55 cases and negative in 164. The overall sensitivity and specificity in identifying patients with small-bowel lesions were 84.7% and 96.9%, respectively. The negative and positive predictive values were 94.5% and 90.9%, respectively. Findings of pathologic examination confirmed small-bowel tumor in 50 patients with carcinoid tumor (n = 19), adenocarcinoma (n = 7), lymphoma (n = 5), jejunal adenoma (n = 9), stromal tumor (n = 5), ectopic pancreas (n = 2), angiomatous mass (n = 2), or metastasis (n = 1). Five examinations resulted in false-positive findings. CONCLUSION: Contrast- and water-enhanced multidetector CT enteroclysis had an overall accuracy of 84.7% for depiction of small-bowel neoplasms.     

False-negative results at multi-detector row CT colonography: multivariate analysis of causes for missed lesions

PURPOSE: To determine causes of false-negative results at multi-detector row computed tomographic (CT) colonography and determine presumptive causes with logistic regression analysis. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. The study included 394 colonic segments in 31 men and 25 women at high risk for colorectal cancer (mean age +/- standard deviation, 60.2 years +/- 9.3 for men and 56.8 years +/- 13.3 for women). Multi-detector row CT colonography and colonoscopy (reference standard) were performed in a blinded manner, and the results were compared. CT colonographic findings were interpreted in consensus by two readers using a primary two-dimensional with three-dimensional problem-solving approach. Adequacy of colonic preparation and distention was recorded. Sensitivity and specificity were obtained with 95% confidence intervals (CIs). Lesions missed at CT colonography were retrospectively reassessed to identify why they were missed, and, if the causes were not apparent, logistic regression analysis was performed to determine the presumptive causes. RESULTS: Colonic preparation and distention were optimal in 17 patients (30%) but suboptimal in 37 (66%) and poor enough to make the results nondiagnostic in two (4%). Twenty-nine of 63 lesions were missed at CT colonography. When all flat, sessile, and pedunculated lesions (n = 63) were included, sensitivities were 75% (nine of 12; 95% CI: 48%, 100%) for lesions 10 mm or larger and 79% (19 of 24; 95% CI: 65%, 93%) for those 6 mm or larger. When only sessile and pedunculated lesions (n = 60) were included, corresponding sensitivities were 100% (nine of nine; 73%, 100%) and 90% (19 of 21; 78%, 100%), respectively. All three missed lesions larger than 10 mm were flat, and all three flat lesions were missed. Two 3-mm high lesions, including one invasive adenocarcinoma, were misinterpreted as feces at blinded image review; one 1-mm high tubular adenoma with adenocarcinoma foci could not be visualized even in retrospect. Sessile or pedunculated polyps 5 mm or smaller were significantly more likely to be missed than those 6 mm or larger (adjusted odds ratio, 11.6; P = .027). CONCLUSION: Aside from inadequate bowel preparation and/or distention, flat lesions and small polyps are the two main causes for missed lesions at multi-detector row CT colonography.     

Acute appendicitis: comparison of low-dose and standard-dose unenhanced multi-detector row CT

PURPOSE: To prospectively compare low- and standard-dose unenhanced multi-detector row computed tomography (CT) in patients suspected of having acute appendicitis. MATERIALS AND METHODS: Ninety-five consecutive patients underwent two unenhanced multi-detector row CT examinations with 4 x 2.5-mm collimation, 120 kVp, and 30 and 100 effective mAs. Two radiologists independently read the images obtained at each dose during two sessions. Readers recorded visualization of the appendix and presence of gas in its lumen, appendicolith, periappendiceal fat stranding, cecal wall thickening, and abscess or phlegmon to measure the diameter of the appendix and to propose diagnosis (appendicitis or alternative). Data were compared according to dose and reader, with definite diagnosis established on basis of surgical findings (n = 37) or clinical follow-up. chi(2) tests and logistic regression were used. Measurement agreements were assessed with Cohen kappa statistics. RESULTS: Twenty-nine patients had a definite diagnosis of appendicitis. No difference was observed between the frequency of visualization of the appendix (P =.874) neither in its mean diameter (P =.101-.696, according to readers and sessions) nor in the readers' overall diagnosis (P =.788) at each dose. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of each sign were not different between doses. Fat stranding, appendicolith, and diameter were the most predictive signs, regardless of dose, yielding approximately 90% of correct diagnoses. The ability to propose a correct alternative diagnosis was not influenced by the dose. CONCLUSION: Low-dose unenhanced multi-detector row CT has similar diagnostic performance as standard-dose unenhanced multi-detector row CT for the diagnosis of acute appendicitis.     

Biphasic CT with mesenteric CT angiography in the evaluation of acute mesenteric ischemia: initial experience

PURPOSE: To evaluate the sensitivity and specificity of biphasic computed tomography (CT) with mesenteric CT angiography in the diagnosis of acute mesenteric ischemia (AMI). MATERIALS AND METHODS: Sixty-two patients with clinically suspected AMI underwent prospective imaging with biphasic multi-detector row CT. Mesenteric CT angiography was performed with 1.25-mm collimation starting 25 seconds after 140 mL of intravenous contrast agent was administered at a rate of 4 mL/sec, followed by portal venous phase imaging with 5-mm collimation and a 60-70-second delay. CT angiograms were reconstructed with multiplanar (including transverse), maximum intensity projection, and volume-rendered techniques. All scans were evaluated prospectively by two independent radiologists for CT evidence of ischemia. AMI was confirmed with surgical or pathologic proof in 25 of 26 patients. In one patient, AMI was confirmed with clinical findings and serial CT examinations. In patients with AMI, sensitivity and specificity of each CT sign were calculated retrospectively by using patients who did not have intestinal ischemia as a control group. CT criteria that optimized sensitivity and specificity for the diagnosis of AMI were then developed. RESULTS: AMI was diagnosed in 26 patients. The CT angiogram depicted arterial disease in eight patients and altered care in five. A finding of any one of pneumatosis intestinalis, venous gas, superior mesenteric artery occlusion, celiac and inferior mesenteric artery occlusion with distal SMA disease, or arterial embolism was 100% specific but only 73% sensitive. Alternatively, a finding of bowel wall thickening in addition to focal lack of bowel wall enhancement, solid organ infarction, or venous thrombosis was 50% sensitive and 94% specific. By using either of these criteria for the diagnosis, a sensitivity of 96% and a specificity of 94% can be achieved. CONCLUSION: Biphasic CT with mesenteric CT angiography is effective in the diagnosis of AMI.