Chui-Mei Tiu

Systematic analysis of missed extremity fractures in emergency radiology

Purpose: To systematically analyze fractures in the extremities that were missed in the initial radiological report, primarily on plain radiographs, in the emergency department (ED). Material and Methods: From January 2003 to June 2004, 2407 new patients were confirmed to have fractures in the extremities in the ED. A total of 3081 fractures were confirmed. In the initial radiological reports, 115 fractures in 108 patients were missed. One musculoskeletal radiologist and one emergency radiologist independently carried out a second review of these images. The easily missed fracture sites were recorded. The possible reasons for misinterpretation were determined by consensus. Results: The most frequent location for missed fractures, expressed as a percentage of all fractures in the same location, was the foot (7.6%), followed by the knee (6.3%), elbow (6.0%), hand (5.4%), wrist (4.1%), hip (3.9%), ankle (2.8%), and shoulder (1.9%). The average percentage for all missed fractures was 3.7%. On the second review, 70% of the initially missed fractures were identified. Analysis of the possible reasons for missed fractures showed the most common reason was subtlety of the fracture. Conclusion: The overall percentage of missed fractures in the extremities was 3.7%. Only 33% of the initially missed fractures were attributed to radiographically imperceptible lesions. Adequate training for physicians and radiologists in the ED may reduce the rate of missed fractures.

Imaging studies of pyriform sinus fistula

BackgroundPyriform sinus fistula (PSF) refers to a persistent embryologic third or fourth pharyngeal pouch, which typically presents as a congenital sinus tract that originates from the pyriform sinus. The sinus tract is often diagnosed by a barium study or direct endoscopic inspection. Utilization of advanced imaging studies, including ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI), may aid in the diagnosis of this disease entity.ObjectivesTo review the imaging findings of PSF and demonstrate the value of various cross-sectional imaging (US, CT, and MRI) in the diagnosis of PSF.Materials and methodsPSF in five children was verified surgically. Preoperative barium esophagography, US, CT, and MRI were performed selectively in these patients. The clinical and imaging findings are reviewed retrospectively.ResultsBarium studies demonstrated the sinus tract in all five patients. US, CT, and MRI demonstrated an associated inflammatory process. By utilizing the trumpet maneuver, the presence of sinus tract was evident in two patients during US. The sinus tract is also demonstrated by CT in another patient.ConclusionsAlthough barium esophagography is advantageous in demonstration of the sinus tract in PSF, US and CT are also capable of showing the sinus tract. The extent of inflammatory process related to PSF is better delineated by US, CT, and MRI.

Automated Full-field Breast Ultrasonography: The Past and The Present

Ultrasonography (US) has been used as an important adjunct to mammography (MG) for about 20 years, and during this period the diagnostic accuracy of US has increased remarkably. A conventional 2-dimensional MG only detects a summation of the X-ray opacity of the whole thickness of breast tissue over the entire breast, while US can separately detect the sonographic properties of the breast tissue in a fashion of contiguous slices. Automated full-field breast US (AFBUS) scanners were originally designed to effectively examine the breast in its entirety. Basically, AFBUS scanners are either prone or supine types. The old generation prone-type scanner consists of a large water-filled tank with the transducers mounted at the base. The patient is prone with the breast freely suspended in the warm water bath. The first prone-type AFBUS scanner (Octoson, 3 to 4.5 MHz; Ultrasound Institute, Sydney, Australia) was used from the late 1970s to late 1980s. It was a specially designed scanner comprising eight transducers immersed at the base of a large water tank. When used for breast scanning, a combination of three to four transducers was usually utilized to obtain an optimal compound image of the breast. The Labsonics scanner, a representative scanner of old-generation supine type, was a simple B-mode single-crystal high-resolution automated unit (7.5 MHz; Labsonics, Indianapolis, IN, USA) that was used from the mid-1980s to mid-1990s. The scanner provided multiple static images of the breast. The patient was supine and a water bag technique was used for sound wave transmission to the breast. With the rapid development of computer technologies, volumetric ultrasound can now be applied for the breasts. Volumetric ultrasound scanning of the breast has been proposed as a complimentary modality for breast cancer screening. There are two types: compression and suspension; the latter is not commercially available outside Japan (ASU-1004, Aloka, Japan). The compression type consists of two major designs: upright and supine types. In the upright-type compression method, the breast is placed and compressed between a film sheet and a compression plate. The new supine-type compression AFBUS scanning apparatus comprises a rigid and substantially stationary frame and a compressive membrane (a polyester film sheet). By manually pushing the frame to contact firmly with the relatively soft breast, the transducer can optimally scan the breast if a sufficient amount of gel is evenly applied on the breast surface, leaving minimal or no contact artifacts. It was originally hoped that AFBUS would rival MG as a screening procedure in asymptomatic women. However, the images obtained from the automated scanners of the old generation were of inferior quality to those generated by hand-held real-time scanners. Nevertheless, the current automated scanners equipped with high-frequency broadband transducers are still significantly competing with hand-held instruments. The current high-resolution AFBUS scanners can provide better demonstration of the breast anatomy and proper orientation and documentation of the lesions detected, and therefore better reproducibility and are good for follow-up studies. The volumetric data obtained can provide potential information for computer-aided detection and diagnosis of breast lesions. With current volumetric technologies, the AFBUS system can provide even higher detection rate of lesions including solid lesions and carcinomas. Interpretation of the imaging results from the volumetric AFBUS should be based on all the imaging data obtained. The current AFBUS scanners are easy to use and need only a short period of training, and the examination technique is especially suitable for technologists or sonographers to perform the whole scanning procedure. AFBUS may be used as an adjunct to MG or as baseline US examination of the breast and can play an important role in screening nonpalpable tumors in women with dense breasts. However, AFBUS in its current form cannot replace MG in detecting malignancy presenting as only microcalcifications.

Differentiating Colonic Diverticulitis from Colon Cancer: The Value of Computed Tomography in the Emergency Setting

Background: The purpose of this study was to establish practical diagnostic criteria to differentiate colonic diverticulitis from colon cancer by computed tomography (CT) in the emergency department (ER). Methods: Helical CT scans of 40 patients admitted to the ER with the clinical diagnosis of diverticulitis and 14 patients diagnosed with colon cancer were retrospectively reviewed. In total, 18 imaging parameters were analyzed and were compared between the 2 groups of patients. Results: Thirteen parameters were found to be statistically significant for the diagnosis of colonic diverticulitis in excluding colon cancer: pericolic infiltration (p < 0.001); presence of lymph nodes (p < 0.001); inflamed diverticula (p = 0.001); non‐inflamed diverticula (p = 0.001); degree of enhancement (p = 0.001); intestinal obstruction (p = 0.001); involved wall thickness (p = 0.005); lymph node size (p = 0.007); fascial thickening (p = 0.009); pattern of enhancement (p = 0.012); involved length (p = 0.014); free air (p = 0.035); and abscess formation (p = 0.042). Among these parameters, the most valuable imaging findings for diverticulitis were the presence of non‐inflamed diverticulum, inflamed diverticulum, mild degree of enhancement, and small lymph node size. Three were found to have high specificity but low sensitivity: target enhancement pattern; abscess formation; and free air. When colonic obstruction is present, colon cancer is more likely than diverticulitis. Conclusion: Specific CT criteria help to differentiate colonic diverticulitis from colon cancer. CT scan with intravenous contrast administration would be the best noninvasive imaging modality in the ER for the accurate diagnosis and appropriate management of such disease.

Can acute cholecystitis with gallbladder perforation be detected preoperatively by computed tomography in ED?: Correlation with clinical data and computed tomography features

PURPOSE The purpose of this study is to determine which computed tomography (CT) findings and clinical data can help to diagnose gallbladder perforation in acute cholecystitis. MATERIALS AND METHODS The medical records and CT findings of patients with surgically proven acute cholecystitis within the last recent 5 years were retrospectively reviewed and compared between 2 groups with and without gallbladder perforation. RESULTS A total of 75 patients with acute cholecystitis were included in the study, and 16 patients were proven to have gallbladder perforation. Higher mortality rate was found in the perforation group (18.8% vs 1.7%; P = .029). Older age (>70 years; P = .004) and higher percentage of segmented neutrophil (>80%; P = .027) were significant clinical factors for predicting gallbladder perforation in acute cholecystitis. The significant CT signs related to gallbladder perforation included visualized gallbladder wall defect (P = .000), intramural gas (P = .043), intraluminal gas (P = .000), intraluminal membrane (P = .043), pericholecystic abscess or biloma formation (P = .009), intraperitoneal free air (P = .001), and presence of ascites in the absence of hypoalbuminemia or other intraabdominal malignancy (P = .017). In multivariate analysis, visualized gallbladder wall defect was the most significant predicting CT feature for diagnosing gallbladder perforation in acute cholecystitis. CONCLUSION Elderly patients with higher segmented neutrophil and CT signs of gallbladder wall defect associated with acute cholecystitis may have high possibility of gallbladder rupture.

Reappraisal of radiographic signs of pneumoperitoneum at emergency department

PURPOSE This study aimed to evaluate the sensitivities of the reported free air signs on supine chest and abdominal radiographs of hollow organ perforation. We also verified the value of supine radiographic images as compared with erect chest and decubitus abdominal radiographs in detection of pneumoperitoneum. METHODS Two hundred fifty cases with surgically proven hollow organ perforation were included. Five hundred twenty-seven radiographs were retrospectively reviewed on the picture archiving and communication system. Medical charts were reviewed for operative findings of upper gastrointestinal tract, small bowel, or colon perforations. The variable free air signs on both supine abdominal radiographs (KUB) and supine chest radiographs (CXR) were evaluated and determined by consensus without knowledge of initial radiographic reports or final diagnosis. Erect CXR and left decubitus abdominal radiographs were evaluated for subphrenic free air or air over nondependent part of the right abdomen. RESULT Upper gastrointestinal tract perforation was proven in 91.2%; small bowel perforation, in 6.8%; and colon perforation, in 2.0%. The positive rate of free air was 80.4% on supine KUB, 78.7% on supine CXR, 85.1% on erect CXR, and 98.0% on left decubitus abdominal radiograph. Anterior superior oval sign was the most common radiographic sign on supine KUB (44.0%) and supine CXR (34.0%). Other free air signs ranged from 0% to 30.4%. CONCLUSIONS Most free air signs on supine radiographs are located over the right upper abdomen. Familiarity with free air signs on supine radiographs is very important to emergency physicians and radiologists for detection of hollow organ perforation.

Gray-scale and color Doppler ultrasonographic features of pleomorphic adenoma and Warthin's tumor in major salivary glands

UNLABELLED Our aim was to assess the specific ultrasonic characteristics of pleomorphic adenoma and Warthins tumor in major salivary glands. METHODS We retrospectively reviewed and analyzed the ultrasonographic (US) features of 19 pleomorphic adenomas in 16 patients and 29 Warthins tumors in 20 patients. The features included tumor size, echotexture, boundary, and shape on gray-scale US imaging and grading and distribution of tumor vascularity on color Doppler ultrasound (CDU). RESULTS All lesions were hypoechoic, and only 22.9% had a homogeneous echotexture. Most of the tumors (87.5%) were >or=10 mm, and 93.8% were well defined. On CDU, 91.7% had intermediate (+ and ++) grades of vascularity. Only two of 29 Warthins tumors had the highest grade of vascularity (+++). Predominantly central blood flow was present in 58.6% of Warthins tumors and 42.1% of pleomorphic adenomas. Lobulated margin (shape) was noted in 84.2% of pleomorphic adenomas and 51.7% of Warthins tumors (P<.05). Anechoic cystic components were present in 13 (44.8%) of 29 Warthins tumors and in only one pleomorphic adenoma (1/19, 5.3%) (P<.01). CONCLUSION Most pleomorphic adenomas were lobulated. Internal anechoic cystic components were absent from pleomorphic adenomas but present in some Warthins tumors. The grading and distribution of blood flow signals on CDU provided only limited additional diagnostic information for distinguishing pleomorphic adenomas from Warthins tumors. Gray-scale ultrasonography is a useful method for evaluating and distinguishing pleomorphic adenomas from Warthins tumors.

Acute Urinary Retention as the Presentation of Imperforate Hymen

Acute urinary retention is unusual in children and is usually a candidate for visiting the emergency department upon initial discovery. We report a 12-year-old girl who complained of acute urinary retention. Ultrasonography demonstrated a large echogenic mass over the vagina and mild dilation of the uterus. Imperforate hymen associated with hematocolpos and hematometrium was diagnosed. Cruciate hymenotomy was performed. The symptoms resolved after treatment. Adolescent girls who complain of urinary symptoms with no previous menstruation should have their external genitalia examined in order to rule out the possibility of imperforate hymen as the cause of acute urinary retention.

Tumor and tumor-like lesions of duodenum: CT and barium imaging features

Neoplasms of the duodenum, either primary or secondary, are uncommon. However, imaging diagnosis for presurgical evaluation is extremely important due to complex regional anatomy. Computed tomography (CT) and barium-based double contrast examination (UGI series) are most frequently employed to evaluate the tumor invasion and intraluminal mucosal pattern. In this pictorial review, the CT and UGI series imaging features of benign and malignant duodenal tumors and tumor-like lesions are demonstrated and discussed.

Computer-Aided Diagnosis for 3-D Power Doppler Breast Ultrasound

In recent studies, both tumor morphology and vascularity played an important role in differentiating breast tumors. In this article, a computer-aided diagnosis (CAD) system was proposed to quantify the tumor morphology of vascularity on three-dimensional (3-D) power Doppler breast ultrasound (PDUS) images. We segmented the tumor margin by the level set method and skeletonized vessels by the 3-D thinning algorithm from 3-D PDUS data to capture the B-mode and vascularity features. The B-mode features including texture, shape and ellipsoid fitting and the vascularity features containing volume, complexity, length, radius and tortuosity were used to differentiate breast tumors. In the experiment, 82 biopsy-verified lesions including 41 benign and 41 malignant lesions were used to test the performance of the proposed system. The proposed method performed well, achieving accuracy, sensitivity, specificity and Az values of 85.37% (70/82), 85.37% (35/41), 85.37% (35/41) and 0.9104, respectively.