Interruption of gallbladder wall with pericholecystic fluid: a CT finding of perforation

In this report, we present an unusual case of gallbladder perforation due to acalculous cholecystitis, masked clinically by acute pancreatitis. Severe abdominal pain referred to the patient's back, nausea, vomiting, and high serum and urinary amylase values were compatible with acute pancreatitis. However, on contrast-enhanced CT, the size and appearance of the pancreas were normal while the gallbladder was abnormally enlarged with a wall defect indicating perforation, soon afterward confirmed by surgery.     

CT diagnosis of extraperitoneal rupture of aortic aneurysm into the anterior abdominal wall

With CT we studied the case of a 98-year-old patient who exhibited a large chronic infrarenal aneurysm with a thin leakage resulting in collection of blood directly within the muscles of the anterior abdominal wall. There was no massive intra- or extraperitoneal hemorrhage. The only imaging differential diagnosis we considered was a spontaneous hemorrhage in the anterior abdominal wall.     

Emphysematous cholecystitis as a cause of retroperitoneal air

Several causes of retroperitoneal air detection have been described. We will add another occurrence, central anterior pararenal air collection as a consequence of perforated emphysematous cholecystitis. We report a case demonstrated by computed tomography and we illustrate the points of interest of this finding.     

The role of spiral CT vs plain films in acute cervical spine trauma: a comparative study

Purpose: To compare the diagnostic yield of conventional radiographs versus helical computed tomography (CT) in screening acute trauma patients. Methods: We reviewed 604 trauma patients who presented to our level I trauma emergency room and underwent both conventional radiography and spiral CT of the cervical spine of. Results: Of the 604 patients, 30 (5.13 %) had fractures seen on helical CT, only 10 of which were diagnosed on conventional radiography. Conclusion: In the screening of acute trauma patients, conventional radiography is less sensitive in detecting fractures than helical CT. CT should therefore be considered as a standard modality choice in such cases.     

Computed chest tomography in an animal model for decompression sickness: radiologic, physiologic, and pathologic findings

This study was conducted to investigate the early pulmonary effects of acute decompression in an animal model for human decompression sickness by CT and light microscopy. Ten test pigs were exposed to severe decompression stress in a chamber dive. Three pigs were kept at ambient pressure to serve as controls. Decompression stress was monitored by measurement of pulmonary artery pressure and arterial and venous Doppler recording of bubbles of inert gas. Chest CT was performed pre- and postdive and in addition the inflated lungs were examined after resection. Each lung was investigated by light microscopy. Hemodynamic data and bubble recordings reflected severe decompression stress in the ten test pigs. Computed tomography revealed large quantities of ectopic gas, predominantly intravascular, in three of ten pigs. These findings corresponded to maximum bubble counts in the Doppler study. The remaining test pigs showed lower bubble grades and no ectopic gas by CT. Sporadic interstitial edema was demonstrated in all animals – both test and control pigs – by CT of resected lungs and on histologic examination. A severe compression–decompression schedule can liberate large volumes of inert gas which are detectable by CT. Despite this severe decompression stress, which led to venous microembolism, CT and light microscopy did not demonstrate changes in lung structure related to the experimental dive. Increased extravascular lung water found in all animals may be due to infusion therapy. Received: 7 December 1998; Revision received: 2 June 1999; Accepted: 9 June 1999     

CT features of gastric lymphoma

The gastrointestinal tract is the most frequent site of extranodal involvement by lymphoma and stomach is the most frequently involved. The incidence of gastric lymphoma appears to be rising as that of adenocarcinoma is declining. It produces a spectrum of radiologic appearances and its distinction from adenocarcinoma is difficult since their findings frequently overlap. The aim of this article is to present pictorially a spectrum of CT findings of the gastric lymphoma. Received: 11 August 1998; Revision received: 26 March 1999; Accepted: 30 June 1999     

Computed tomography of the thorax in HIV disease

A wide variety of thoracic disorders can arise in patients infected with the human immunodeficiency virus (HIV), although recent developments in the therapeutic management of AIDS patients has resulted in a changing pattern of chest disease. The use of CT in the diagnosis and management of these thoracic manifestations is discussed along with the CT appearances of the various infectious and non-infectious complications of the acquired immune deficiency syndrome (AIDS) which are commonly encountered in clinical practice. Received: 28 September 1998; Revision received: 28 December 1998; Accepted: 26 January 1999     

Primary seminoma of the retroperitoneum

A rare case of primary seminoma in the retroperitoneum is described. Ultrasound detected a huge hypoechoic mass and correlative computed tomography showed a midline, homogeneous, lobulated mass in a man who presented for anuria. Received: 1 April 1999; Revised: 28 June 1999; Accepted: 27 July 1999     

Postoperative findings following the Whipple procedure: determination of prevalence and morphologic abdominal CT features

This study was conducted to determine characteristic CT findings following the Whipple procedure and to evaluate the usefulness of CT in predicting tumor recurrence. Eighty-four postoperative abdominal CT scans and medical records of 43 patients were retrospectively reviewed. Perioperative histopathologic examinations revealed malignancy in 32 patients (74.4 %). Time interval between surgery and CT varied from 13 days to 6 years and 7 months. Common postoperative findings were unopacified anastomotic bowel loops in the porta hepatis (n = 69 scans), perivascular cuffing (n = 42 scans), pneumobilia (n = 40 scans), dilated intrahepatic bile ducts (n = 22 scans), reactive lymphadenopathy (n = 21 scans), and transient fluid collections (n = 20 scans). Postoperative complications were detected on 17 CT scans (20.2 %): generalized ascites (n = 8 patients), deep abscesses (n = 3 patients), wound abscess (n = 1 patient), pancreatitis (n = 1 patient), and pseudomembranous colitis (n = 1 patient). Tumor recurrence appeared in 15 patients (46.8 %) after a mean postoperative period of 11 months (1 month to 3 years): local (9 of 15), regional lymph nodes (9 of 15), and liver metastasis (8 of 15). Detection of generalized ascites more than 30 days after surgery was associated with tumor recurrence in 6 of 6 patients (100 %). Diffuse ascites (> 30 days after surgery) behaved as an early predictive sign of tumor recurrence. In our series CT accuracy for detecting recurrent tumor with CT was 93.5 %. No predilection site for disease recurrence could be determined. Received: 1 February 1999; Revised: 15 April 1999; Accepted: 19 April 1999     

Radiographically occult ureteral calculi in an HIV-positive child undergoing indinavir therapy

Helical CT has been shown to be a sensitive and specific tool for the rapid diagnosis of obstructing urinary tract calculi. AIDS patients taking the protease inhibitor indinavir, however, can develop urinary tract calculi that are invisible on CT. We present a case of a 9-year-old HIV-positive girl who developed acute ureteral obstruction while taking indinavir. Helical CT after the administration of intravenous contrast demonstrated signs of ureteral obstruction although no obstructing calculus was visualized. This case demonstrates that obstructing ureteral calculi secondary to indinavir therapy may not be visualized with helical CT, unlike nearly all other obstructing calculi. When secondary signs of obstruction are seen in these patients, the radiologist must have a high index of suspicion for urinary tract calculi even without direct visualization of a stone.     

Mammary tuberculosis: percutaneous treatment of a mammary tuberculous abscess

It is currently very rare to find mammary involvement in cases of tuberculosis, in either primary or secondary form. Diagnosis is classically clinical and microbiological, and the basic techniques used in imaging diagnosis are mammography and ultrasound. Computed tomography may define the involvement of the thoracic wall in those cases which present as mammary masses adhering to deep levels, and is also able to evaluate accompanying pulmonary disease, if it is present. Traditionally, treatment has consisted of quadrantectomy and specific antibiotic therapy. We present a case of tuberculous mammary abscess secondary to pulmonary disease, which was treated by percutaneous drainage controlled by CT and specific antibiotic therapy. We revise the diagnosis, differential diagnosis and treatment of mammary tuberculosis. Received: 27 July 1998; Revision received: 2 February 1999; Accepted: 20 April 1999     

Omental infarction associated with right-sided heart failure

A 31-year-old man with a known congenital heart disease presented with cardial decompensation and an acute abdomen with tenderness in the right inferior abdominal quadrant. Because infectious parameters were slightly elevated, acute appendicitis was suspected. A CT scan showed an isolated focal infiltration of the omentum, superficial to the ascending colon, small amounts of ascites, and dilated hepatic and mesenteric veins. Laparoscopic resection and histopathologic examination confirmed hemorrhagic omental infarction due to thromboses of several small omental veins. This is a report on the pathogenesis, differential diagnoses, and CT findings of omental infarction. Received: 14 July 1999; Revised: 12 October 1999; Accepted: 4 November 1999     

Right adrenal hematoma following hepatectomy

We present the findings and possible causes in three cases of postoperative adrenal hematomas. In 16 cases of 45 consecutive patients, following segmental right or left lobe hepatectomy, CT was performed in order to evaluate possible fluid collection or other complications. In all cases imaging findings and a correlation with preoperative CT scans were done. Follow-up CT examinations were also reviewed. In three cases solid suprarenal masses with attenuation values consistent with adrenal hematomas were found. Preoperative scans at the same level indicated normal adrenal glands. Follow-up scans revealed the hematoma, stable in size, for up to 12 weeks, although lower attenuation values were evident. Right adrenal hematoma is a possible postoperative complication following hepatectomy; if it remains stable in size, it can be left alone. Received: 29 December 1998; Revised: 25 March 1999; Accepted: 18 May 1999     

Three-dimensional contrast-enhanced MRI using an intravascular contrast agent for detection of traumatic intra-abdominal hemorrhage and abdominal parenchymal injuries: an experimental study

The aim of this study was to compare the performance of 3D MRI in conjunction with an intravascular contrast agent to spiral contrast-enhanced CT, regarding the detection of abdominal parenchymal injuries as well as peritoneal hemorrhage in an animal model. Liver and kidney injuries were created surgically in six female pigs under general anesthesia. All pigs underwent contrast-enhanced spiral CT and 3D MR imaging following administration of an intravascular contrast agent (NC100150 Injection). Two readers rated their confidence independently on MR and CT data sets using a five-point scale for the presence of organ injury and hemoperitoneum. Autopsy findings served as standard of reference. Sensitivity and specificity for MR in detecting hepatic and renal injuries as well as hemoperitoneum was 100 %. Computed tomography was less accurate with sensitivity and specificity values of 90 and 94 %, respectively. Receiver operating characteristics (ROC) analysis revealed a higher confidence when interpretation was based on MR images. In an animal model 3D MR imaging in conjunction with an intravascular contrast agent proved highly accurate in detecting and localizing parenchymal injuries to the upper abdomen as well as in detecting intraperitoneal blood collections. Received: 4 November 1999, Revised: 5 May 2000, Accepted: 9 May 2000     

Rheumatoid arthritis of the craniocervical region: assessment and characterization of inflammatory soft tissue proliferations with unenhanced and contrast-enhanced CT

The aim of this study was to depict and characterize inflammatory soft tissue proliferations caused by rheumatoid arthritis (RA) in the craniocervical region by unenhanced and contrast-enhanced CT. Computed tomography of the craniocervical region was performed in 35 patients in the axial plane before and after the i. v. administration of contrast material. According to the densities and contrast enhancement of the inflammatory soft tissue proliferations, four groups were classified. Ancillary findings, such as a compression of the dural sac or spinal cord, erosions of the bony structures, and atlantoaxial subluxation, were also evaluated. Inflammatory soft tissue proliferations were depicted in 28 of 35 patients and could be differentiated by unenhanced and contrast-enhanced CT according to the above defined criteria: effusion in 6 patients (17 %); hypervascular pannus in 8 (23 %); hypovascular pannus in 5 (14 %); and fibrous tissue in 9 patients (26 %). A compression of the dural sac was seen in 11 (31 %) patients; 3 of these had neurological symptoms. Erosions of the odontoid process were found in 20 (57 %) patients; 16 (80 %) of these also showed erosions of the atlas. Atlantoaxial subluxation was seen in 11 (31 %) patients. Inflammatory soft tissue proliferations in the craniocervical region caused by RA can be reliably demonstrated and classified by unenhanced and contrast-enhanced CT, which can differentiate between joint effusion and various forms of pannus and depict ancillary findings. Computed tomography is an alternative method for patients unable to undergo an MRI examination. Received: 4 October 1999; Revised: 7 March 2000; Accepted: 14 March 2000     

Significance of backboard artifacts on portable trauma series chest radiographs

Purpose: To evaluate the degree to which the artifacts created by the radio-opaque components of a backboard obscure the findings on the initial trauma series chest radiograph (BBCXR). Methods: We reviewed 40 consecutive trauma victims admitted to our level I trauma center over a 3-month period who underwent a follow-up portable supine chest radiograph (PCXR) off the backboard no longer than 1 h after the initial trauma BBCXR. The original interpretation of the BBCXR was compared to the reading of the PCXR as well as to a retrospective analysis of the BBCXR performed by two radiologists blinded as to the findings on the original report. Results: The initial interpretation of the BBCXR failed to identify abnormalities reported in the follow-up PCXR of 10 individuals (25 %), most frequently bone fractures, misplaced hardware, and pleural effusions. Of these missed abnormalities, 80 % were identified retrospectively. Conversely, the initial reading of the BBCXR described a widened mediastinum in five cases, right upper lobe opacities in two, and cardiomegaly in one. Of these eight reported findings, only five (63 %) – the cardiomegaly and four of the mediastinal abnormalities – were also reported upon retrospective analysis, while the PCXR taken with the patient off the backboard confirmed widened mediastinum in only three cases. Conclusions: The initial, often hurried reading of a portable chest radiograph taken on a backboard as part of a trauma series often misses significant pathology, most of which can be detected upon more thorough examination of the original film. The backboard also tends to magnify mediastinal structures more than routine PCXR. Therefore, we advocate a more cautious analysis of the original BBCXR and routine utilization of a follow-up PCXR to confirm mediastinal abnormalities.     

CT evaluation of appendicitis and diverticulitis. Part II: Diverticulitis

CT has become the primary imaging modality for evaluation of possible diverticulitis. In studies of patients taken to surgery for suspected diverticulitis without first undergoing CT, 25–33 % of resected specimens show no inflammation. The overall accuracy of CT in establishing or excluding the diagnosis is between 84 and 99 %. In patients without diverticulitis, an alternative diagnosis is seen in 50–58 % of cases. The appearance of carcinoma with perforation and diverticulitis may be the same, and, as a result, the degree of certainty in the diagnosis should be stated. Techniques include use of either oral and intravenous contrast or rectally administered contrast. No case of colonic perforation due to rectally administered water-soluble contrast for CT has been reported, although there have been cases of perforation using barium and fluoroscopy. All techniques scan the entire abdomen and pelvis since there are frequent alternative diagnoses seen beyond the area of initial pain.     

CT evaluation of appendicitis and diverticulitis. Part I: Appendicitis

CT has become the primary imaging modality for evaluation of possible appendicitis. About 20 % of patients taken to surgery for appendicitis without CT have had a normal appendix removed. CT has demonstrated overall accuracy of between 93 % and 98 %. Alternative diagnoses are seen in 34–80 % of patients without appendicitis but who were suspected of having appendicitis. For evaluation of appendicitis different techniques have been successful, including the use of no contrast, use of oral and intravenous contrast, and use of rectally administered contrast. Scanning of the entire abdomen and pelvis and scanning of an area limited to the right lower quadrant are also options. Ultrasonography has been shown to have a role in pediatric patients. If ultrasonography is positive, CT is not necessary. If ultrasonography is negative, CT should follow.     

CT scanning of children with blunt abdominal trauma – is oral contrast useful?

Purpose: To determine the usefulness of oral contrast in CT scanning of children with blunt abdominal trauma by comparing scans performed with and without oral contrast. Methods: CT scans of 273 children with abdominal trauma and 40 without trauma were reviewed. Results: Of the trauma patients, 116 (43 %) were scanned with oral contrast, 157 (57 %) without. Among the children who underwent laparotomy, CT scanning identified 6 of 6 organ injuries in those scanned with oral contrast and 11 of 12 in those scanned without. CT scanning identified all bowel injuries. The pancreatic body and tail were significantly better visualized in scans with oral contrast. Detection of pancreatic or liver injury was not, however, significantly different in the two groups. Opacification of the bowel by contrast was significantly better in elective than in trauma patients. Conclusion: There was no difference in detection of injuries between children scanned with and without oral contrast.     

Mediastinal myelolipoma: CT and MRI appearances

A 72-year-old man presented with a mediastinal mass on chest radiograph. Computed tomography and MR imaging showed that the mass consisted of both fatty and small nodular soft tissue components, highly suggestive of an extramedullary hematopoiesis or a myelolipoma. A CT-guided needle biopsy was next performed and confirmed the diagnosis. We discuss the CT and MR imaging appearances of this tumor and usefulness of a CT-guided needle biopsy to avoid surgery in asymptomatic patients. Received: 8 March 1999; Revised: 23 June 1999; Accepted: 25 June 1999