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R Brooke Jeffrey

Publications and source records attributed to R Brooke Jeffrey.

At least 19 recordsLinked to original sources
PubMed2006

CT colonography: influence of 3D viewing and polyp candidate features on interpretation with computer-aided detection.

PURPOSE: To retrospectively determine if three-dimensional (3D) viewing improves radiologists' accuracy in classifying true-positive (TP) and false-positive (FP) polyp candidates identified with computer-aided detection (CAD) and to determine candidate polyp features that are associated with classification accuracy, with known polyps serving as the reference standard. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained; this study was HIPAA compliant. Forty-seven computed tomographic (CT) colonography data sets were obtained in 26 men and 10 women (age range, 42-76 years). Four radiologists classified 705 polyp candidates (53 TP candidates, 652 FP candidates) identified with CAD; initially, only two-dimensional images were used, but these were later supplemented with 3D rendering. Another radiologist unblinded to colonoscopy findings characterized the features of each candidate, assessed colon distention and preparation, and defined the true nature of FP candidates. Receiver operating characteristic curves were used to compare readers' performance, and repeated-measures analysis of variance was used to test features that affect interpretation. RESULTS: Use of 3D viewing improved classification accuracy for three readers and increased the area under the receiver operating characteristic curve to 0.96-0.97 (P<.001). For TP candidates, maximum polyp width (P=.038), polyp height (P=.019), and preparation (P=.004) significantly affected accuracy. For FP candidates, colonic segment (P=.007), attenuation (P<.001), surface smoothness (P<.001), distention (P=.034), preparation (P<.001), and true nature of candidate lesions (P<.001) significantly affected accuracy. CONCLUSION: Use of 3D viewing increases reader accuracy in the classification of polyp candidates identified with CAD. Polyp size and examination quality are significantly associated with accuracy.

Adult↗
PubMed2005

Management of thyroid nodules detected at US: Society of Radiologists in Ultrasound consensus conference statement.

The Society of Radiologists in Ultrasound convened a panel of specialists from a variety of medical disciplines to come to a consensus on the management of thyroid nodules identified with thyroid ultrasonography (US), with particular focus on which nodules should be subjected to US-guided fine needle aspiration and which thyroid nodules need not be subjected to fine-needle aspiration. The panel met in Washington, DC, October 26-27, 2004, and created this consensus statement. The recommendations in this consensus statement, which are based on analysis of the current literature and common practice strategies, are thought to represent a reasonable approach to thyroid nodular disease.

Humans↗
PubMed2005

The sonographic features of papillary thyroid carcinomas: pictorial essay.

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy in children and adults, with an incidence of 22,000 cases per year in the United States. Differentiating PTC from more frequently occurring benign thyroid nodules has proved challenging as there may be significant overlap in their clinical presentation and sonographic appearance. That said, high-resolution ultrasound provides a safe and affordable way of identifying and characterizing thyroid nodules and guiding percutaneous biopsies. Although no single sonographic feature is pathognomonic for PTC, certain features should raise suspicion and the combination of several features may be even more suggestive. In this pictorial essay, we describe the high-resolution sonographic features of pathologically proven PTCs. The nodule number, echo texture, internal architecture, calcifications, margins, contours, vascularity, and lymph nodes are considered. While the classic sonographic description of PTC is a solitary, hypoechoic solid nodule with microcalcifications and intrinsic vascularity, in practice, PTC may manifest with a myriad of sonographic appearances making biopsy necessary for a definitive diagnosis.

Biopsy, Fine-Needle↗
PubMed2004

Surface normal overlap: a computer-aided detection algorithm with application to colonic polyps and lung nodules in helical CT.

We developed a novel computer-aided detection (CAD) algorithm called the surface normal overlap method that we applied to colonic polyp detection and lung nodule detection in helical computed tomography (CT) images. We demonstrate some of the theoretical aspects of this algorithm using a statistical shape model. The algorithm was then optimized on simulated CT data and evaluated using a per-lesion cross-validation on 8 CT colonography datasets and on 8 chest CT datasets. It is able to achieve 100% sensitivity for colonic polyps 10 mm and larger at 7.0 false positives (FPs)/dataset and 90% sensitivity for solid lung nodules 6 mm and larger at 5.6 FP/dataset.

Algorithms↗
PubMed2004

Automatic detection and classification of hypodense hepatic lesions on contrast-enhanced venous-phase CT.

The objective of this work was to develop and validate algorithms for detection and classification of hypodense hepatic lesions, specifically cysts, hemangiomas, and metastases from CT scans in the portal venous phase of enhancement. Fifty-six CT sections from 51 patients were used as representative of common hypodense liver lesions, including 22 simple cysts, 11 hemangiomas, 22 metastases, and 1 image containing both a cyst and a hemangioma. The detection algorithm uses intensity-based histogram methods to find central lesions, followed by liver contour refinement to identify peripheral lesions. The classification algorithm operates on the focal lesions identified during detection, and includes shape-based segmentation, edge pixel weighting, and lesion texture filtering. Support vector machines are then used to perform a pair-wise lesion classification. For the detection algorithm, 80% lesion sensitivity was achieved at approximately 0.3 false positives (FP) per slice for central lesions, and 0.5 FP per slice for peripheral lesions, giving a total of 0.8 FP per section. For 90% sensitivity, the total number of FP rises to about 2.2 per section. The pair-wise classification yielded good discrimination between cysts and metastases (at 95% sensitivity for detection of metastases, only about 5% of cysts are incorrectly classified as metastases), perfect discrimination between hemangiomas and cysts, and was least accurate in discriminating between hemangiomas and metastases (at 90% sensitivity for detection of hemangiomas, about 28% of metastases were incorrectly classified as hemangiomas). Initial implementations of our algorithms are promising for automating liver lesion detection and classification.

Algorithms↗
PubMed2004

Registration of central paths and colonic polyps between supine and prone scans in computed tomography colonography: pilot study.

Computed tomography colonography (CTC) is a minimally invasive method that allows the evaluation of the colon wall from CT sections of the abdomen/pelvis. The primary goal of CTC is to detect colonic polyps, precursors to colorectal cancer. Because imperfect cleansing and distension can cause portions of the colon wall to be collapsed, covered with water, and/or covered with retained stool, patients are scanned in both prone and supine positions. We believe that both reading efficiency and computer aided detection (CAD) of CTC images can be improved by accurate registration of data from the supine and prone positions. We developed a two-stage approach that first registers the colonic central paths using a heuristic and automated algorithm and then matches polyps or polyp candidates (CAD hits) by a statistical approach. We evaluated the registration algorithm on 24 patient cases. After path registration, the mean misalignment distance between prone and supine identical anatomic landmarks was reduced from 47.08 to 12.66 mm, a 73% improvement. The polyp registration algorithm was specifically evaluated using eight patient cases for which radiologists identified polyps separately for both supine and prone data sets, and then manually registered corresponding pairs. The algorithm correctly matched 78% of these pairs without user input. The algorithm was also applied to the 30 highest-scoring CAD hits in the prone and supine scans and showed a success rate of 50% in automatically registering corresponding polyp pairs. Finally, we computed the average number of CAD hits that need to be manually compared in order to find the correct matches among the top 30 CAD hits. With polyp registration, the average number of comparisons was 1.78 per polyp, as opposed to 4.28 comparisons without polyp registration.

Algorithms↗
PubMed2004

Periaortic hematoma at diaphragmatic crura at helical CT: sign of blunt aortic injury in patients with mediastinal hematoma.

PURPOSE: To evaluate periaortic hematoma (PH) near the level of the diaphragm at abdominal computed tomography (CT) as an indirect sign of acute traumatic aortic injury after blunt trauma in patients with mediastinal hematoma. MATERIALS AND METHODS: From 1998 to 2001, 97 patients with CT evidence of mediastinal hematoma after blunt thoracic trauma were retrospectively identified at two level 1 trauma centers. The presence or absence of PH near the level of the diaphragmatic crura was retrospectively established by a blinded reviewer at each institution. Aortic injury status was determined by reviewing angiographic, surgical, and clinical records. Sensitivity, specificity, positive and negative productive values, and positive and negative likelihood ratios were calculated. RESULTS: Among the 97 patients with mediastinal hematoma, 14 had both PH near the level of the diaphragm and aortic injury; six had aortic injuries without PH, five had PH near the level of the diaphragm without aortic injury, and 72 had no evidence of PH near the diaphragm and no aortic injury. Sensitivity for PH near the level of the diaphragm as a sign of aortic injury was 70%; specificity, 94%; positive predictive value, 74%; and negative predictive value, 92%. The positive likelihood ratio for the presence of aortic injury was 10.8, and the negative likelihood ratio was 0.3. CONCLUSION: PH near the level of the diaphragmatic crura is an insensitive but relatively specific sign for aortic injury after blunt trauma. The presence of this sign at abdominal CT should prompt imaging of the thoracic aorta to evaluate potential thoracic aortic injury.

Adolescent↗
PubMed2004

MDCT in Pancreatic adenocarcinoma: prediction of vascular invasion and resectability using a multiphasic technique with curved planar reformations.

OBJECTIVE: The objective of our study was to determine the negative predictive value of MDCT with curved planar reformations for detecting vascular invasion and predicting overall resectability in patients with pancreatic adenocarcinoma. MATERIALS AND METHODS: Imaging findings related to vascular invasion and overall tumor resectability in 25 patients who underwent contrast-enhanced biphasic MDCT evaluation were correlated with actual vessel invasion and overall resectability determined at surgery and pathologic examination. The presence of vascular invasion was assessed in 110 major peripancreatic vessels in 22 patients who underwent resection. RESULTS: On MDCT, 23 (92%) of 25 patients were deemed to have resectable pancreatic adenocarcinoma. The tumors in the remaining two (8%) were considered not resectable because of the presence of vascular invasion (which was confirmed in only one patient at surgery). Of those 23 patients deemed to be candidates for curative resection on the basis of MDCT results, 20 were found to have resectable adenocarcinoma at time of surgery, yielding a negative predictive value for MDCT of 87% (20/23 patients) for overall resectability. In the other three patients, adenocarcinoma was deemed to be unresectable because of small metastases to the liver (two patients) or to the peritoneum (one patient) discovered at surgery. For detection of vascular invasion, MDCT yielded a negative predictive value of 100% (108/108 vessels) with no false-negative findings and an accuracy of 99% (109/110 vessels) with 108 true-negative findings, one true-positive finding, and one false-positive finding. CONCLUSION: Our preliminary data on MDCT show that the technique has excellent negative predictive value for vascular invasion and good negative predictive value for overall tumor resectability in patients with pancreatic adenocarcinoma, suggesting an improvement over previous results reported using single-detector CT. The problem of undetected micrometastases to the liver and peritoneum remains.

Adenocarcinoma↗
PubMed2004

Increased through-transmission in abdominal tuberculous lymphadenitis.

OBJECTIVE: To describe 2 cases of abdominal tuberculosis in which sonographic evaluation of mesenteric lymphadenopathy showed increased through-transmission suggestive of caseating necrosis. METHODS: Two patients with abdominal pain and other symptoms (including fever, diarrhea, and weight loss) underwent abdominal sonography with a 6-MHz curved array transducer. One patient also underwent sonographically guided fine-needle aspiration of multiple lymph nodes, and the other underwent computed tomography, colonoscopy, and colon biopsy. RESULTS: In both patients, sonography showed multiple rounded hypoechoic lesions with increased ultrasound through-transmission suggestive of necrotic lymphadenopathy. No color flow was shown. In 1 case, the posterior acoustic enhancement was accentuated in the harmonic imaging mode. In the other case, the lesions shown on sonography corresponded to computed tomographic findings of low-density lymph nodes. Results of fine-needle aspiration and colon biopsy were positive for tuberculosis. CONCLUSIONS: Posterior acoustic enhancement in abdominal lymphadenopathy can suggest the diagnosis of tuberculous lymphadenitis. Detection of this finding is facilitated by scanning in the harmonic mode. Necrotic nodes will lack color flow and can be distinguished from lymphadenopathy of other causes. Sonography can also be used for fine-needle aspiration of necrotic nodes to yield a definitive diagnosis.

Abdomen↗
PubMed2003

Multidetector CT of pancreatic adenocarcinoma: diagnostic advances and therapeutic relevance.

Detection and staging of pancreatic malignancies remains a challenge for radiologists. Considering the poor prognosis of pancreatic adenocarcinoma, accurate preoperative staging is the key to a possibly curative surgical treatment. Contrast-enhanced helical CT has been the most commonly used for evaluation of pancreatic cancer in many institutions, although it suffers from many limitations. With the fast pace of advances in multidetector CT (MDCT), and the beginning clinical implementation of 16-row scanners, improvements in spatial resolution in the z-axis with near-isotropic imaging provide exquisite multiplanar reconstructions of pancreatic anatomy. This article provides an overview of current MDCT technique and protocols for assessment of pancreatic adenocarcinoma, and describes new 3D-display methods for effective visualization of large data sets provided by MDCT.

Carcinoma, Pancreatic Ductal↗
PubMed2003

Laparoscopic radical nephrectomy incorporating intraoperative ultrasonography for renal cell carcinoma with renal vein tumor thrombus.

The purpose of this study was to describe the technique of laparoscopic right radical nephrectomy incorporating intraoperative, real-time ultrasonography in the management of renal cell carcinoma with level 1 renal vein tumor thrombus. With the patient in a modified flank position, a transperitoneal four-port approach was used to laparoscopically resect an 8.5-cm right renal mass with tumor thrombus extending to, but not into, the inferior vena cava. Early arterial control with gentle traction on the right renal vein provided a short proximal renal venous segment devoid of tumor on laparoscopic inspection. Intraoperative laparoscopic ultrasonography allowed confident identification of the proximal extent of the tumor thrombus. After hilar control, complete resection and intact removal of the renal specimen was performed using standard non-hand-assisted laparoscopic techniques. The actual surgical time was 180 minutes. Surgical resection was successfully performed laparoscopically. No postoperative complications or hospital readmission occurred. Pathologic examination confirmed T3b renal cell carcinoma with negative surgical margins. Laparoscopic right radical nephrectomy incorporating intraoperative, real-time ultrasonography is feasible in the management of renal cell carcinoma with a large-sized level 1 renal vein thrombus. Additional studies are necessary to evaluate its role in urologic oncologic surgery.

Aged↗
PubMed2003

Common and uncommon sonographic features of papillary thyroid carcinoma.

OBJECTIVE: To determine the relative frequency of various sonographic findings in papillary carcinoma of the thyroid. METHODS: We retrospectively analyzed the sonographic features in 55 patients with proven papillary carcinoma of the thyroid. Sonographic features analyzed were echo texture, cystic change, margin, contour, presence of a peripheral halo, vascularity, and calcification pattern. Features were classified as common (> or = 35% of cases) or uncommon (< 10% of cases). Combinations of features were also analyzed. RESULTS: Common sonographic features of papillary carcinoma included hypoechoic texture (86%), microcalcifications (42%) or no calcifications (47%), well-defined margins (47%), and intrinsic hypervascularity (69%). Uncommon features included hyperechoic or mixed echo texture, cystic elements, irregular margins, hypovascularity, and coarse or peripheral calcifications. Of the 29 lesions that had calcifications, 20 (69%) had microcalcifications; 5 (17%) had coarse calcifications; and 1 had peripheral calcifications. In total, 54% of cases had at least 1 uncommon feature, and 11% had 2 or more uncommon features. Cystic carcinomas were rare and accounted for only 6% of lesions; all had hypervascular solid components. No carcinomas in our series were completely avascular. CONCLUSIONS: There is a broad spectrum of sonographic findings in papillary carcinoma of the thyroid. Half of the lesions in this series had at least 1 uncommon sonographic feature.

Carcinoma, Papillary↗
PubMed2003

Surgical management of adrenal cysts.

Adrenal cysts are rare and are often found incidentally during abdominal imaging for another reason. We describe two cases of adrenal cysts, one of which was found to be a cystic pheochromocytoma. Most cystic pheochromocytomas are not diagnosed by urinary screening studies, and the first indication of a pheochromocytoma may be hemodynamic instability during resection. We review the literature on adrenal cysts and make recommendations for the management of cystic adrenal masses.

Adrenal Gland Diseases↗
PubMed2002

Multidetector-row CT and volumetric imaging of pancreatic neoplasms.

Multidetector-row CT provides excellent visualization of the pancreas and peripancreatic structures, yielding information that is crucial for detecting pancreatic neoplasms and accurately determining their staging. This new technology enables the acquisition of large volumetric data sets to create high-quality curved planar reformations that clearly depict the common bile duct, the pancreatic duct, and the peripancreatic vasculature. Additionally, curved planar reformations highlight critical anatomic and pathologic relationships which are useful for surgical planning in patients with resectable disease.

Adenocarcinoma↗
PubMed2002

Ultrasonography.

Diagnostic sonography is experiencing a breath-taking period of technological advancement. Ultrasound contrast agents, new imaging techniques, and handheld instruments will play a role in facilitating more diagnostic power in high-end imaging and insuring more widespread use of diagnostic sonography in medicine in general.

Bile Ducts↗