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Biomedical subjects

Pablo R Ros

Publications and source records attributed to Pablo R Ros.

At least 37 records · Page 2Linked to original sources
PubMed2003

MR imaging features of solid pseudopapillary tumor of the pancreas in adult and pediatric patients.

OBJECTIVE: This study was conducted to describe the MR imaging features of solid pseudopapillary tumor of the pancreas. CONCLUSION: Solid pseudopapillary tumor of the pancreas, a tumor typically seen in young women, is a large, well-defined, encapsulated lesion with heterogeneous high or low signal intensity on T1-weighted, heterogeneous high signal intensity on T2-weighted, and early peripheral heterogeneous enhancement with progressive fill-in on gadolinium-enhanced dynamic MR imaging. These features help differentiate this rare tumor from other pancreatic neoplasms.

Adolescent↗
PubMed2003

CT features with pathologic correlation of acute gastrointestinal graft-versus-host disease after bone marrow transplantation in adults.

OBJECTIVE: This study was conducted to describe the CT features of acute gastrointestinal graft-versus-host disease in adults and to correlate these findings with the pathologic grades of disease severity. MATERIALS AND METHODS: Patients (n = 22) with a history of allogeneic bone marrow transplantation and pathologically confirmed acute gastrointestinal graft-versus-host disease underwent contrast-enhanced (n = 13) and unenhanced (n = 9) CT. CT scans were retrospectively evaluated for intestinal and extraintestinal abnormalities by two radiologists who were unaware of the biopsy results. The CT findings were correlated with the pathologic grade of disease severity using the Pearson's correlation coefficient and the two-tailed nonparametric Spearman's rank correlation coefficient. RESULTS: CT features included small-bowel wall thickening (22/22), engorgement of the vasa recta adjacent to affected bowel segments (20/22), stranding of the mesenteric fat (16/22), large-bowel wall thickening (13/22), bowel dilatation proximal to thickened wall segments (5/22), ascites (10/22), periportal edema (8/22), mucosal enhancement (7/13), and serosal enhancement (4/13). The wall thickening had a discontinuous distribution in nine patients (41%). Bowel wall thickening was associated with high-grade graft-versus-host disease in patients in whom the distal esophagus (p = 0.015), ileum (p = 0.034), or ascending colon (p = 0.05) was involved. Increasing numbers of thickened bowel segments correlated with high-grade graft-versus-host disease (r = 0.548, p = 0.008). Increasing numbers of abnormal CT findings did not correlate with high-grade graft-versus-host disease (r = 0.117, p = 0.604). CONCLUSION: A variety of bowel abnormalities can be seen on CT in patients with acute graft-versus-host disease. CT findings associated with high-grade graft-versus-host disease are thickening of the distal esophagus, ileum, or ascending colon, as well as increasing numbers of thickened bowel wall segments.

Acute Disease↗
PubMed2003

Rectal inflammation as first manifestation of graft-vs-host disease: radiologic-pathologic findings.

Graft-vs-host disease (GVHD) is a common, life-threatening complication of bone marrow transplantation that frequently involves the gastrointestinal tract. Since symptoms are typically nonspecific, radiologic examination is often performed to reach a diagnosis. To the best of our knowledge, this is the first reported radiologic description of a case of rectal involvement as the first manifestation of GVHD. The differential diagnosis of segmental rectal wall thickening in a patient following bone marrow transplantation should include GVHD.

Adult↗
PubMed2002

"Cecal gangrene": a rare cause of right-sided inferior abdominal quadrant pain, fever, and leukocytosis.

We report on a 58-year-old man with known diabetes, congestive heart failure, and need for chronic hemodialysis presenting with right lower abdominal quadrant pain, fever, and leukocytosis. Although initial clinical findings were highly suggestive of acute appendicitis, CT revealed marked circumferential wall thickening of the cecum, which was interpreted as cecal infarction by the radiologist. Intraoperatively, cecal necrosis was confirmed, but the ileocecal valve and, especially, the appendix showed no ischemia. No vascular occlusions were found. Histopathologic analysis of the resected cecum demonstrated isolated transmural cecal necrosis with marked infiltration of the cecal wall by numerous bacteria and neutrophils. We present the CT features and histopathologic findings of isolated cecal gangrene, review the pathogenesis of occlusive and nonocclusive cecal ischemia or infarction, and discuss the role of bacterial superinfection as a potential cofactor in the pathogenesis of isolated cecal necrosis which should be included in the differential diagnosis of right-sided inferior abdominal quadrant pain.

Journal Article↗
PubMed2002

CT findings in isolated ischemic proctosigmoiditis.

The purpose of our study was to describe the CT features of ischemic proctosigmoiditis in correlation with clinical, laboratory, endoscopic, and histopathologic findings. Our study included seven patients with isolated ischemic proctosigmoiditis. Patients were identified by a retrospective review of all histopathologic records of colonoscopic biopsies performed during a time period of 4 years. All patients presented with left lower abdominal quadrant pain, bloody stools, and leukocytosis, and four patients had fever at the time of presentation. Four of seven patients suffered from diarrhea, one of seven was constipated and two of seven had normal stool consistency. The CT examinations were reviewed by two authors by consensus and compared with clinical and histopathologic results as well as with the initial CT diagnosis. The CT showed a wall thickening confined to the rectum and sigmoid colon in seven of seven patients, stranding of the pararectal fat in four of seven, and stranding of the perisigmoidal fat in one of seven patients. There were no enlarged lymph nodes, but five of seven patients showed coexistent diverticulosis and in three of these patients CT findings were initially misinterpreted as sigmoid diverticulitis. Endoscopies and histopathologic analyses of endoscopic biopsies confirmed non-transmural ischemic proctosigmoiditis in all patients. Isolated ischemic proctosigmoiditis often presents with unspecific CT features and potentially misleading clinical and laboratory findings. In an elderly patient or a patient with known cardiovascular risk factors the diagnosis of ischemic proctosigmoiditis should be considered when wall thickening confined to the rectum and sigmoid colon is seen that is associated with perirectal fat stranding.

Aged↗
PubMed2002

Advances in imaging for pancreatic disease.

Pancreatic imaging is an essential tool in the early diagnosis and staging of pancreatic disease. This review analyzes the most recent advances in pancreatic imaging. The specific modalities discussed include helical computed tomography (HCT) and multislice CT (MSCT), CT angiography, magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP), and positron emission tomography (PET). At present, MSCT is generally viewed as the most efficient modality for initial detection and staging of pancreatic carcinoma, with an accuracy rate of about 95% to 97% for initial detection and virtually 100% for staging. CT is also the initial imaging modality used in evaluation of acute pancreatitis. However, recently, MRI has been viewed increasingly as a more precise diagnostic tool in this subgroup of patients. MRCP has been accepted as the primary imaging technique in the diagnosis of chronic pancreatitis. PET imaging, on the other hand, has an increasing role in the staging of pancreatic carcinoma, for which it may be the modality of choice in detection of extrapancreatic metastasis.

Adenocarcinoma↗
PubMed2002

MR imaging in chronic hepatitis and cirrhosis.

The role of magnetic resonance imaging (MRI) in the evaluation of diffuse parenchymal abnormalities of the liver has been expanded by recent technical advances of MR systems as well as the evolution of intravenous contrast media. Currently, MR is undoubtedly the most useful imaging modality for detecting the presence of chronic liver disease. Tailored sequences allow acurate depiction of specific disorders, including steatohepatitis and iron-overload states. Morphologic changes and signal intensity effects not only facilitate the diagnosis of chronic liver disease with MRI but they also help to distinguish between different etiologies, and they assist in staging the histologic severity of certain chronic conditions. Moreover, the faster MRI scanning techniques presently available permit the dynamic assessment of contrast enhancement, which permits improved characterization of focal hepatic lesions, including regenerative nodules, dysplastic nodules, and hepatocellular carcinoma (HCC). Although overlap in MRI findings still may exist among different types of chronic liver disease and among focal liver lesions, familiarity with certain specific imaging features may be diagnostic in the proper clinical setting. Finally, comprehensive MRI examination, including MR angiography and MR cholangiography, is the most sensitive and cost-effective technique for detecting extrahepatic disease, diagnosing vascular disorders, and evaluating the patient before or after liver transplantation. This article focuses on the current role of MR imaging in patients with chronic liver disease. The subjects covered include the detection and characterization of chronic hepatitis and cirrhosis, specific findings seen in steatohepatitis and certain metabolic diseases, the evaluation of extrahepatic vascular complications of cirrhosis, and patient assessment before and after liver transplantation. The characterization of hepatic masses is also included briefly. This subject is covered in greater depth elsewhere in this issue.

Chronic Disease↗
PubMed2002

Volume and impact of second-opinion consultations by radiologists at a tertiary care cancer center: data.

RATIONALE AND OBJECTIVES: Patients with cancer who are referred to a dedicated oncology center usually have undergone previous imaging studies that the oncologists typically desire to have reviewed by radiologists. Such reinterpretations can be complex and time-consuming, yet many institutions do not systematically account for them as part of the total workload. The purpose of this study was to ascertain the numbers and types of second-opinion consultations performed by radiologists at a tertiary care cancer center, and to assess their effect on work volume. MATERIALS AND METHODS: A survey of referring clinicians was undertaken to evaluate the numbers and types of second-opinion consultations requested of radiologists at the Dana Farber Cancer Institute during a 12-month period. Consultations included review of studies from outside institutions, and cases from Dana Farber in which further comparison was needed. The number of consultations requiring additional tumor size measurements was tallied. The mean daily number of new studies interpreted by radiologists was used as a benchmark of work volume. RESULTS: Radiologists performed 4,664 consultations during 254 workdays, interpreting a mean of 18 additional studies (range, 4-42) per day as a result of referrals for second opinion. These included 3,638 (78%) cross-sectional studies (ie, computed tomographic [CT], magnetic resonance [MR], and ultrasound [US] studies), 674 (14%) mammograms, 220 (5%) plain radiographs, 132 (3%) nuclear medicine scans, and one galactogram. Of the 4,664 consultations, 1,306 (28%) were performed to obtain tumor measurements, many of these involving five to 10 bidimensional calculations per study. A mean of 101 new examinations per day was performed by radiologists during the same 12-month period, including cross-sectional studies (CT and US scans) (56%), plain radiographs (34%), and mammograms (11%). MR imaging was not performed. CONCLUSION: Second-opinion consultations increased the average daily work volume by 18%. This has implications for workforce, as well as for compensation in terms of relative value units and finances for this previously unquantified service.

Academic Medical Centers↗
PubMed2002

Hepatic imaging. An overview.

For optimal detection and characterization of focal or diffuse liver disease, it is essential to obtain the most appropriate imaging test in the correct clinical setting. Access to clinical information and medical history is, therefore, essential. Moreover, familiarity with currently available modalities for imaging the liver [figure: see text] allows the optimal use of the technical advances in ultrasound imaging, CT scanning, MR imaging, and nuclear scintigraphy technology and contributes to improved diagnostic accuracy.

Humans↗
PubMed2002

Current techniques of computed tomography. Helical CT, multidetector CT, and 3D reconstruction.

The many recent advances in CT technology have secured its position as the modality of choice in routine liver imaging and have improved its performance in several problem-solving applications. In addition, improvements in postprocessing software (e.g., in speed, efficiency, and automated algorithms) have increased their use in clinical practice. Multiplanar reformations, 3D renderings, and high-quality CT angiographic displays have become extremely valuable both in image interpretation and in communicating information to surgeons and referring physicians.

Angiography↗
PubMed2002

Magnetic resonance imaging. Liver-specific contrast agents.

MR imaging with new liver-specific contrast agents will probably be the imaging modality used in the future to detect focal liver lesions. The detection of HCC will probably be improved by using specific hepatobiliary agents, but the exact technique remains to be determined. New liver-specific contrast can differentiate some benign lesions from malignant ones and can assist in making a final diagnosis. In certain circumstances, liver-specific contrast agents can be used to evaluate hepatic vessels, the biliary tract, and hepatic function. New applications are also expected.

Contrast Media↗
PubMed2002

Benign liver neoplasms.

A variety of benign focal liver lesions are easily characterized with currently available imaging techniques and contrast agents. The most common benign liver lesions, such as hemangioma, bile duct cyst, and FNH, reveal characteristic cross-sectional imaging features that allow an accurate diagnosis. For atypical variants and more uncommon lesions, including HCA, angiomyelioma, infantile hemagioendothelioma, and mesenchymal hamartoma, integration of clinical data can often help in the interpretation of imaging studies. Finally, for the remaining lesions, such as hepatic adenomatosis, the imaging findings may not be specific enough to negate the need for a tissue biopsy.

Adenoma↗
PubMed2002

Computed tomography and magnetic resonance imaging of hepatic metastases.

The detection and characterization of liver metastases is well performed with either computed tomography or magnetic resonance imaging. The administration of intravenous contrast is essential for almost all indications, with multiphasic imaging aiding in lesion characterization and detection. The use of multidetected CT (MDCT) provides the ability for optimized vascular and multiplanar imaging, but has also resulted in increased examination complexity. Tissue-specific MR contrast agents can yield the highest rate of lesion detection and thus may be useful in presurgical planning.

Contrast Media↗
PubMed2002

Diffuse liver disease.

During the last decade, the role of the radiologist in evaluating patients with diffuse liver disease has increasingly expanded. In many cases, the management choices for the hepatologist in the imaging work-up of a patient with suspicion of a diffuse liver disease have significantly widened. In some instances, imaging may point directly to the diagnosis; in many instances, imaging helps narrow the differential diagnosis or is crucial in the follow-up of patients. Although some rare entities still have nonspecific radiologic features, the imaging pattern, in combination with appropriate clinical information, may provide the most likely diagnosis.

Humans↗
PubMed2002

Detection of liver metastases: comparison of gadobenate dimeglumine-enhanced and ferumoxides-enhanced MR imaging examinations.

PURPOSE: To compare gadobenate dimeglumine (Gd-BOPTA)-enhanced magnetic resonance (MR) imaging with ferumoxides-enhanced MR imaging for detection of liver metastases. MATERIALS AND METHODS: Twenty consecutive patients known to have malignancy and suspected of having focal liver lesions at ultrasonography (US) underwent 1.0-T MR imaging with gradient-recalled-echo T1-weighted breath-hold sequences before, immediately after, and 60 minutes after Gd-BOPTA injection. Subsequently, MR imaging was performed with turbo spin-echo short inversion time inversion-recovery T2-weighted sequences before and 60 minutes after ferumoxides administration. All patients subsequently underwent intraoperative US within 15 days, and histopathologic analysis of their resected lesion-containing specimens was performed. Separate qualitative analyses were performed to assess lesion detection with each contrast agent. Quantitative analyses were performed by measuring signal-to-noise and contrast-to-noise ratios (CNRs) on pre- and postcontrast Gd-BOPTA and ferumoxides MR images. Statistical analyses were performed with Wilcoxon signed rank and Monte Carlo tests. RESULTS: Sensitivity of ferumoxides-enhanced MR imaging was superior to that of Gd-BOPTA-enhanced MR imaging for liver metastasis detection (P <.05). Ferumoxides MR images depicted 36 (97%) of 37 metastases detected at intraoperative US, whereas Gd-BOPTA MR images depicted 30 (81%) metastases during delayed phase and 20 (54%) during dynamic phase. All six metastases identified only at ferumoxides-enhanced MR imaging were 5-10 mm in diameter. There was a significant increase in CNR between the lesion and liver before and after ferumoxides administration (from 3.8 to 6.8, P <.001) but not before or after Gd-BOPTA injection (from -4.8 to -5.5, P >.05). CONCLUSION: Ferumoxides-enhanced MR imaging seems to be superior to Gd-BOPTA-enhanced MR imaging for liver metastasis detection.

Colorectal Neoplasms↗
PubMed2001

Portal-venous gas unrelated to mesenteric ischemia.

The aim of this study was to report on 8 patients with all different non-ischemic etiologies for portal-venous gas and to discuss this rare entity and its potentially misleading CT findings in context with a review of the literature. The CT examinations of eight patients who presented with intrahepatic portal-venous gas, unrelated to bowel ischemia or infarction, were reviewed and compared with their medical records with special emphasis on the pathogenesis and clinical impact of portal-venous gas caused by non-ischemic conditions. The etiologies for portal-venous gas included: abdominal trauma ( n=1); large gastric cancer ( n=1); prior gastroscopic biopsy ( n=1); prior hemicolectomy ( n=1); graft-vs-host reaction ( n=1); large paracolic abscess ( n=1); mesenteric recurrence of ovarian cancer superinfected with clostridium septicum ( n=1); and sepsis with Pseudomonas aeruginosa ( n=1). The clinical outcome of all patients was determined by their underlying disease and not negatively influenced by the presence of portal-venous gas. Although the presence of portal-venous gas usually raises the suspicion of bowel ischemia and/or intestinal necrosis, this CT finding may be related to a variety of non-ischemic etiologies and pathogeneses as well. The knowledge about these conditions may help to avoid misinterpretation of CT findings, inappropriate clinical uncertainty and unnecessary surgery in certain cases.

Abdominal Injuries↗