Abdominal Computed Tomography Studies Research Articles

An Institutional Review of Splenic Artery Aneurysm in Childbearing-Aged Females and Splenic Artery Aneurysm Rupture During Pregnancy. Is Screening Justified?

To determine the prevalence of splenic artery aneurysm (SAA) in women of childbearing age and the incidence of peripartum rupture to ascertain a possible benefit of screening this potentially high-risk population. Patients diagnosed with SAA over a 6-year period were collected from a single institutional medical records database. Inclusion criteria included female gender and age between 15 and 49 years. The number of abdominal computed tomography studies performed on our study population during the study period was compared to the number of detected SAAs. The number of deliveries at our institution during the study period was compared to the number of peripartum SAA ruptures. The resultant data were used to calculate the prevalence of SAA in childbearing-aged females and the incidence of SAA rupture during pregnancy. The prevalence of SAA in childbearing-aged females and incidence of rupture during pregnancy were less than 0.1%. Radiologic screening of all childbearing-aged females is not warranted, but identification of those at greater risk of harboring an asymptomatic SAA, along with the early institution of treatment according to current guidelines, may prevent maternal and fetal mortality in the rare event of SAA rupture during pregnancy.

Clinical significance of periportal tracking as an extrarenal manifestation of acute pyelonephritis

The purpose of this study was to evaluate whether hepatic periportal tracking (PPT) in patients with acute pyelonephritis correlates with the severity of pyelonephritis. A database search was conducted of patients with clinically suspected acute pyelonephritis who underwent abdominal computed tomography (CT) between January 2004 and June 2009 for disease evaluation. The final study group consisted of 274 patients (221 women, 53 men) with a mean age of 43 ± 20 years. The abdominal CT studies were retrospectively reviewed by two radiologists by consensus to assess PPT, renal wedge-shaped hypoperfusion areas, and renal abscesses. The laboratory reports obtained on the day of the CT examinations were reviewed for C-reactive protein (CRP), white blood cell count (WBCC), and leukocytes in urine. Presence of PPT was correlated with the presence of renal abscess, extension of renal hypoperfusion areas as well with levels of CRP, leukocytosis, and urine leukocytes using the Fisher's exact Test and the Wilcoxon Test. All patients showed renal hypoperfusion areas consistent with the clinical diagnosis of acute pyelonephritis. Twenty-nine patients (11%) showed PPT which was significantly associated with the extension of the wedge-shaped renal hypoperfusion areas (P < 0.001), the presence of a renal abscess (P < 0.01), as well as the level of CRP (P < 0.001) and urine leukocytes (P < 0.01). A renal abscess was observed in 36% of patients with PPT compared with 14% of patients without PPT. The PPT should be kept in mind as an extrarenal finding in acute pyelonephritis and may indicate a more serious clinical course of the disease.

Optimizing the role of imaging in appendicitis

Acute appendicitis is the most common acute abdominal condition that requires surgical intervention in childhood. From the diagnostic performance perspective, computed tomography (CT) has a significantly higher sensitivity than does ultrasound (US) for diagnosing appendicitis in children; from the safety perspective, however, one should consider the radiation associated with CT, especially in children. There is strong evidence supporting improved patient outcomes in children with suspected acute appendicitis who undergo CT scanning. Nevertheless, we should keep in mind that for a single abdominal CT study in a 5-year-old child, the lifetime risk of radiation-induced cancer would be 26.1 per 100,000 in female and 20.4 per 100,000 in male patients, based on probabilistic models designed with data from atomic bomb survivors. An integrated clinical-imaging approach, applying clinical scores that are able to predict which children with acute abdominal pain do or do not have a high probability of presenting with appendicitis may improve the effectiveness of the imaging diagnosis of appendicitis at the hospital level. Such an approach could avoid exposure of children who at low risk for appendicitis to unnecessary diagnostic tests and eventually, to radiation.

Tomografia computadorizada de abdome normal: estudo retrospectivo das angulações dos hilos renais

OBJETIVO: Obter valores da angulação média dos hilos renais em relação ao plano horizontal, traçado sobre músculos eretores da espinha direito e esquerdo, considerando como parâmetro de referência para as medidas das angulações o centro da coluna vertebral lombar. MATERIAIS E MÉTODOS: Foram analisados 250 exames de tomografia computadorizada de abdomes considerados normais de indivíduos de ambos os sexos, sendo 128 masculinos (idade média de 52,45 ± 17,42 anos) e 122 femininos (idade média de 54,39 ± 18,27 anos), totalizando 500 hilos renais estudados. A angulação média de cada hilo renal em relação ao plano horizontal foi obtida, sendo considerados sempre os ângulos agudos. RESULTADOS: O estudo comparativo entre os sexos mostrou que não houve diferença estatisticamente significante em relação aos ângulos agudos dos hilos renais. A análise estatística mostrou, com intervalo de confiança de 95%, para média do ângulo direito os limites de 40,40° e 44,54° e para o hilo renal esquerdo os limites de 39,91° e 43,23°. CONCLUSÃO: Os hilos renais, independentemente do sexo, apresentam angulações semelhantes. Valores angulares maiores terão anomalia de hiper-rotação ou hiper-rotação exagerada e valores menores terão anomalia de rotação incompleta ou rotação invertida.

Acute Appendicitis in Young Children: Cost-effectiveness of US versus CT in Diagnosis—A Markov Decision Analytic Model

To compare the cost-effectiveness of different imaging strategies in the diagnosis of pediatric appendicitis by using a decision analytic model. Approval for this retrospective study based on literature review was not required by the institutional Research Ethics Board. A Markov decision model was constructed by using costs, utilities, and probabilities from the literature. The risk of radiation-induced cancer was modeled by using the Biological Effects of Ionizing Radiation VII report, which is based primarily on data from atomic bomb survivors. The three imaging strategies were ultrasonography (US), computed tomography (CT), and US followed by CT if the initial US study was negative. The model simulated the short-term and long-term outcomes of the patients, calculating the average quality-adjusted life span and health care costs. For a single abdominal CT study in a 5-year-old child, the lifetime risk of radiation-induced cancer would be 26.1 per 100,000 in female and 20.4 per 100,000 in male patients. In the base-case analysis, US followed by CT was the most costly and most effective strategy, CT was the second-most costly and second-most effective strategy, and US was the least costly and least effective strategy. The incremental cost-effectiveness ratios (ICERs) of CT to US and of US followed by CT to US were both well below the societal willingness-to-pay threshold of $50,000 (in U.S. dollars). The ICER of US followed by CT to CT was less than $10,000 in both male and female patients. In a Markov-based decision model of pediatric appendicitis, the most cost-effective method of imaging pediatric appendicitis was to start with a US study and follow each negative US study with a CT examination.

Correction of oral contrast artifacts in CT-based attenuation correction of PET images using an automated segmentation algorithm

Oral contrast is usually administered in most X-ray computed tomography (CT) examinations of the abdomen and the pelvis as it allows more accurate identification of the bowel and facilitates the interpretation of abdominal and pelvic CT studies. However, the misclassification of contrast medium with high-density bone in CT-based attenuation correction (CTAC) is known to generate artifacts in the attenuation map (mumap), thus resulting in overcorrection for attenuation of positron emission tomography (PET) images. In this study, we developed an automated algorithm for segmentation and classification of regions containing oral contrast medium to correct for artifacts in CT-attenuation-corrected PET images using the segmented contrast correction (SCC) algorithm. The proposed algorithm consists of two steps: first, high CT number object segmentation using combined region- and boundary-based segmentation and second, object classification to bone and contrast agent using a knowledge-based nonlinear fuzzy classifier. Thereafter, the CT numbers of pixels belonging to the region classified as contrast medium are substituted with their equivalent effective bone CT numbers using the SCC algorithm. The generated CT images are then down-sampled followed by Gaussian smoothing to match the resolution of PET images. A piecewise calibration curve was then used to convert CT pixel values to linear attenuation coefficients at 511 keV. The visual assessment of segmented regions performed by an experienced radiologist confirmed the accuracy of the segmentation and classification algorithms for delineation of contrast-enhanced regions in clinical CT images. The quantitative analysis of generated mumaps of 21 clinical CT colonoscopy datasets showed an overestimation ranging between 24.4% and 37.3% in the 3D-classified regions depending on their volume and the concentration of contrast medium. Two PET/CT studies known to be problematic demonstrated the applicability of the technique in clinical setting. More importantly, correction of oral contrast artifacts improved the readability and interpretation of the PET scan and showed substantial decrease of the SUV (104.3%) after correction. An automated segmentation algorithm for classification of irregular shapes of regions containing contrast medium was developed for wider applicability of the SCC algorithm for correction of oral contrast artifacts during the CTAC procedure. The algorithm is being refined and further validated in clinical setting.

Avaliação da reprodutibilidade da tomografia computadorizada no estadiamento da pancreatite aguda

OBJETIVO: Medir a reprodutibilidade da tomografia computadorizada sem e com contraste na avaliação da gravidade da pancreatite aguda. MATERIAIS E MÉTODOS: Cinqüenta e um exames de tomografia computadorizada abdominal sem e com contraste de pacientes com pancreatite aguda foram analisados por dois radiologistas (observadores 1 e 2). Calculamos o índice morfológico pela tomografia computadorizada sem e com contraste, separadamente, e o índice de gravidade da tomografia computadorizada para pancreatite aguda. Medimos a reprodutibilidade intra- e interobservador da tomografia computadorizada através do índice kappa (kapa). RESULTADOS: Para a concordância interobservador obtivemos kapa de 0,666, 0,705, 0,648, 0,547 e 0,631 para índice morfológico sem e com contraste, presença de necrose pancreática, extensão da necrose pancreática e índice de gravidade da tomografia computadorizada, respectivamente. Para a concordância intra-observador dos observadores 1 e 2 obtivemos, respectivamente, kapa de 0,796 e 0,732 para o índice morfológico sem contraste; 0,725 e 0,802 para o índice morfológico com contraste; 0,674 e 0,849 para a presença de necrose pancreática; 0,606 e 0,770 para a extensão da necrose pancreática; e 0,801 e 0,687 para o índice de gravidade da tomografia computadorizada. CONCLUSÃO: O estadiamento da pancreatite aguda pela tomografia computadorizada por meio do índice morfológico e do índice de gravidade da tomografia computadorizada é um método bastante reprodutível. O não-uso do contraste não afeta a reprodutibilidade da tomografia computadorizada para o cálculo do índice morfológico.

Abdominal Computed Tomography Findings of Malignant Tumors in Patients With Solid Organ Transplants

Aims Incidence of malignancy in solid organ transplant recipients is higher compared to the general population. The aim of this study was to characterize distribution and appearance of abdominal malignant tumors detected with spiral computed tomography (CT) examination in patients with solid organ transplantation. Materials and methods Between July 1994 and April 2006, 198 patients underwent liver transplantation and 568 patients underwent renal transplantation in our center. The abdominal CT studies were reviewed to determine the presence or absence of abdominal malignancy. All abdominal CT examinations were performed prior to immunomodulation or chemotherapy. Results Eleven renal and one liver transplantation patient developed an abdominal malignancy. Among 11 renal transplantation patients eight were diagnosed as abdominal Kaposi’s sarcoma (KS) and three as posttransplantation lymphoproliferative disorder (PTLD) upon spiral CT examination. In two patients the transplanted organ itself had malignant tumors: one patient had PTLD with Burkitt lymphoma in the transplanted liver and the other a renal cell carcinoma in the transplanted kidney. Abdominal PTLD and KS showed imaging findings and the site of organ involvement somewhat different from nontransplant patients. The most common pathologies in KS were liver lesions ( n = 6) and lymphadenopathy ( n = 6). But in abdominal PTLD, the spleen ( n = 3) was the most involved organ. Conclusions The early diagnosis of abdominal malignancies after solid organ transplantation is crucial for the patient’s prognosis, especially under immunosuppression. The abdominal spiral CT examination was an effective modality to depict a malignancy among patients with solid organ transplantation.

New techniques for the diagnosis of osteoporosis

In this review article current developments and applications in quantitative osteoporosis imaging are presented. Developments in the field of DXA include geometrical parameters of the proximal femur such as the "hip axis length" and new ROIs to determine BMD. Advances in QCT are new volumetric techniques to quantify BMD at the lumbar spine and the proximal femur. In addition techniques to determine BMD in standard contrast-enhanced abdominal computed tomography studies are described. Currently with the new bone quality concept in full bloom techniques to quantify trabecular bone architecture as new surrogates of bone strength are of increasing significance. Spatial high-resolution techniques such as magnetic resonance imaging and new computed tomography techniques have shown their potential in assessing trabecular bone structure. In addition ultrasound is considered a low-cost technique to explore bone quality.

Is direct radiologist supervision of abdominal computed tomography (CT) scans necessary?

To determine the effect of direct radiological supervision of patients attending for abdominal CT by assessing the frequency of protocol alteration subsequent to radiologist review of the images obtained. A prospective questionnaire-based observational study was performed of 187 consecutive patients undergoing abdominal CT. The CT protocol was determined by a radiologist in advance, with reference to the request form. Any subsequent change in the prescribed study that was contingent on radiologist review of the images obtained was documented on the questionnaire. Comparison was made with a second (control) group of 100 patients undergoing cranial CT. A protocol change was undertaken following radiologist review of the CT images of 17 (9%) of the group undergoing abdominal CT, compared with 14 (14%) of the group undergoing cranial CT. In the abdominal CT group, further scanning was performed for lesion characterization, to guide a subsequent interventional procedure, because of inadequate anatomical coverage or to evaluate an unexpected lung tumour. There was no significant difference in proportions between the two groups (p=0.23). When abdominal and cranial CT studies were compared, there was no significant difference in the proportion of studies requiring a change in the prescribed protocol following radiologist review of the images obtained. There was no evidence to suggest that abdominal CT was any less suited to protocol.

Reducing radiation to children: the resident’s role

Reducing radiation to children: the resident’s role

The Prevalence of Simple Renal and Hepatic Cysts Detected by Spiral Computed Tomography

AIM: To provide a definitive evaluation of the prevalence of simple renal and hepatic cysts using spiral computed tomography (CT). PATIENTS AND METHODS: Contrast-enhanced abdominal CT studies from 617 patients (295 women, 322 men) attending for investigations unrelated to renal or hepatic pathology were included. The number of renal cysts, their location and the diameter of the largest cyst were recorded. Hepatic cysts were recorded as being either present or absent. RESULTS: Two hundred and fifty-four patients (41%) were found to have simple renal cysts and 110 patients were found to have simple hepatic cysts (18%). Both renal and hepatic cysts became more common with age. Renal cysts were significantly more common at all ages in men ( p=0.001), and increased in both size ( p=0.02) and number ( p<0.05) with age. CONCLUSION: A major discrepancy has, until now, existed between autopsy prevalence of renal cysts and prevalence as reported by in-vivo third-generation CT or sonography studies. Using newer spiral CT machines, we have generated prevalence data closer to post-mortem findings. We have also shown a significant, but age dependent, association between the presence of simple hepatic and simple renal cysts ( p=0.001)

CT findings of abdominal tuberculosis in 12 patients

Our purpose was to evaluate the Computed Tomography (CT) findings of the abdominal tuberculosis (TBC) retrospectively which was diagnosed histopatologically. This study included 12 patients. All patients were evaluated by abdominal CT study. Most findings of CT studies were mesenteric calcified or noncalcified lymphadenopathies, ascites, thickened intestinal wall located on the right lower quadrant of abdomen, thickening of peritoneum, mottled soft-tissue densities in omentum and mesenterium. In addition, one of the patients had bilateral calcified adrenal glands and one of them had calcified mass in adrenal gland. If peritoneal thickening, ascites, abdominal lymphadenophaties and thickened intestinal walls are obtained, TBC should be considered in differential diagnosis in developing countries.

Imaging of small bowel Crohn's disease: can abdominal CT replace barium radiography?

Objectives: To analyze imaging features and compare the diagnostic information provided by abdominal computed tomography (CT) and enteroclysis to see whether CT can replace barium examinations in the assessment of patients with small bowel Crohn's disease. Methods: The abdominal CT studies and enteroclysis of 33 patients with small bowel Crohn's disease who underwent both examinations within a 2-week time period were retrospectively reviewed and scored for the presence and severity of the following features: mural edema, ulceration, small bowel obstruction, stricture, sinus tract formation, fistula, abscess, extraintestinal manifestations, and total number of intestinal sites involved. The statistical significance of the differences for each variable was calculated. Results: A total of 37 case sets were reviewed. CT demonstrated 10 (27 %) abscesses compared to 7 (19 %) shown by enteroclysis. Three extraintestinal sites shown by CT were not demonstrated by enteroclysis. Enteroclysis detected a larger number of intestinal sites of involvement (54 vs. 47) and more cases of ulceration (78 % vs. 19 %), small bowel obstruction (46 % vs. 16 %), stricture (38 % vs. 11 %), fistula formation (24 % vs. 8 %), and sinus tract formation (27 % vs. 5 %). The two modalities were similar in characterizing and grading the severity of mural thickening (CT showed 41 %, enteroclysis 46 %). Conclusion: Abdominal CT and enteroclysis provide unique and complementary diagnostic information in patients with Crohn's disease of the small bowel. Both methods may be required for the accurate assessment of the severity and extent of Crohn's disease of the small bowel. The choice of initial examination will depend on the clinical issue in question.

Adrenal macrotumors diagnosed by computed tomography

Adrenal tumors larger than 6 cm are unusual but show a greater incidence of malignant etiologies than smaller adrenal tumors. The scarce information about adrenal macrotumors (AMT) induced us to study prospectively all patients who were seen in our clinic during the period 1984-1988 and were diagnosed by computed tomography (CT) to have an adrenal mass greater than or equal to 6 cm. The clinical characteristics, including the main complaint, tumoral secretory activity, CT findings and histologic diagnosis from 18 patients are described; they represented a 0.3% of the total amount of abdominal CT studies performed. Seventy-two % of AMT resulted to be non cortisol or catecholamines secreting masses, and from them, a 38% corresponded to malignant etiologies characterized by marked and rapid weight loss. Four out of five hormone secreting AMT corresponded to pheochromocytomas, while the fifth one resulted to be a bilateral macronodular hyperplasia secreting cortisol. In two cases AMT did not correspond to a genuine adrenal mass, resulting to be a malignant histocytoma in one case and a hydatidic cyst in other one. When performed in two occasions, a percutaneous needle biopsy was a valuable diagnostic tool, permitting to diagnose a lymphoma and a tuberculoma. 1) AMT correspond mainly to non cortisol or catecholamines secreting tumors, often malignant; 2) not all AMT diagnosed by CT correspond to true adrenal masses; 3) percutaneous needle biopsy can be a helpful procedure for diagnosing nonfunctioning solid AMT.

Treatment of blunt hepatic injuries: role of CT.

Serial dynamic upper abdominal computed tomography (CT) studies were performed on 20 patients as part of the conservative treatment of blunt hepatic injuries (hematoma, laceration, or fracture). Fourteen of these patients had either major or minor associated hemoperitoneum. In 13 patients, hemoperitoneum was either significantly reduced or absent by 1 week. A severe delayed hemorrhage occurred in one patient 7 1/2 days after admission; a large and unchanged volume of intraperitoneal fluid had been seen on a preceding abdominal CT scan. One other patient who had a satisfactory response underwent surgery for a pancreatic laceration. Serial abdominal CT studies are an integral part of the conservative treatment of blunt hepatic injuries and seem to be useful in monitoring resorption of hemoperitoneum and the pattern of healing of intrahepatic hematomas, lacerations, and fractures.

Computed tomography of invasive pleural mesothelioma

The computed tomography (CT) findings in three patients with invasive pleural mesothelioma are presented, and the invasive route and metastatic extension of the disease in the abdomen and retroperitoneum are discussed. These findings indicate the value of CT in detecting the extrathoracic extension of mesothelioma. Abdominal CT studies should be obtained in evaluating mesothelioma patients for extrathoracic extension of the disease.