[PET/CT with (18F)FDG in the initial staging of a pelvic kidney neoplasm. A case report]. / PET-TAC con (18)F-FDG en la estadificación inicial de una neoplasia de pelvis renal. A propósito de un caso.

We report a case of 58-year-old woman referred to our service for an (18)FFDG PET/CT study of initial staging after being diagnosed of a pelvic kidney mass consistent with malignancy. The FDG-PET showed an abnormal mass in the right kidney, a suspicious metastasis versus a second primary tumor in the cortex of the kidney and lymph node infiltration in the paracaval nodes. The histological analysis verification after exeresis of the lesions confirmed the diagnosis of renal metastases. In this article, we present a brief review of the literature published on the role of PET in the characterization and initial staging of kidney and urinary tract tumors. We also stress the clinical importance of carefully evaluating any low attenuation lesion or focal glucose uptake detected in these structures in a PET/CT study with (18)FFDG.

[The percutaneous dissolution treatment of gallstones. Our initial experience]. / Tratamiento disolutivo percutáneo de la litiasis vesicular. Experiencia inicial.

OBJECTIVE: To describe our initial experience in direct contact dissolution of cholesterol gallstones with methyl-tert-butyl ether, a non surgical approach for high risk patients. PATIENTS: Twenty symptomatic patients were preselected. They all had radiolucent stones in functioning gallbladders. Patients rejected elective surgery or were considered to be of high risk for anesthesia. Computerized tomography scan was performed to evaluate stone calcium content and liver-gallbladder anatomy. In selected patients, contact stone dissolution was carried out after transhepatic gallbladder catheterization. RESULTS: Ten patients were excluded due to poor gallbladder contact to the liver (two patients) or stone density greater than 70 Hounsfield Units. Percutaneous transhepatic positioning of the catheter into the gallbladder was achieved in seven patients. Stone dissolution was complete in five patients and partial in one. Mean perfusion time was 6.15 hours (3.45-7.5); however, mean hospitalization stay was 7 days (4-10) mainly due to inexperienced management coordination. While on treatment, all patients experienced nausea, burning or abdominal discomfort that were easily controlled. Complications were related to catheter placement (intraperitoneal biliary leakage, external fistula) and in five patients to the dissolution procedure (severe abdominal pain, biliary colic, cholecystopancreatitis). Complications were all handled with non surgical treatment. CONCLUSIONS: Percutaneous gallstone dissolution with methyl-tert-butyl ether is a rapid and efficacious procedure that can, nevertheless, induce relevant secondary effects and complications.

[Vesicosigmoid fistulas secondary to diverticulitis: helical CT diagnosis]. / Fístulas vesicosigmoideas secundarias a diverticulitis. Diagnóstico mediante tomografía computarizada helicoidal.

Colovesical fistulas are the most common type of vesicointestinal fistula and the most prevalent of these are vesicosigmoid fistulas. In our environment, diverticulitis is the most common cause, accounting for approximately one half of all cases. The literature describes different methods for the diagnosis of colovesical fistula, with computed tomography and cystography being the most useful. We describe two cases of vesicosigmoid fistula secondary to diverticulitis diagnosed at our center using helical computed tomography and review the clinical and radiological findings for this entity.

[Computerized tomography angiography of the renal vessels]. / Angiografía por tomografía computarizada de los vasos renales.

OBJECTIVE: To present the findings and discuss the diagnostic possibilities of helical CT angiography and digital substraction angiography, and to compare their capabilities to depict renal vascular anatomy (arterial and venous) and the pathological changes. METHODS: The findings obtained by the different imaging modalities of CT angiography were compared with those of digital substraction angiography in more than 2000 studies performed at our hospital. RESULTS: Agreement and correlation between CT angiography and digital substraction angiography, the gold standard, were found in the vast majority of the cases. In conjunction, various image post-processing possibilities of CT angiography achieved almost 100% sensitivity and specificity. CONCLUSION: CT angiography is capable of obtaining results that overlap with those of optimum quality digital substraction angiography and is a less invasive and less costly procedure. The time required is shorter and the radiation dose exposure is markedly lower for patient and staff. Helical CT is a minimal invasive technique with an increasing role in the evaluation of the renal vessels. Although its field of applications has not yet been completely established, it is less invasive, less costly, radiation exposure of patient and staff performing the procedure is lower, and has had a considerable impact in the diagnosis and management of vascular disorders. CT angiography is applicable to a number of indications of conventional angiography and has permitted vascular screening studies where one would be reluctant to indicate catheter arteriography. This imaging procedure is mainly used for 1) screening of patients that may have renovascular hypertension that may be amenable to surgical or intraluminal treatment; 2) follow-up of treated patients; 3) preoperative assessment of kidney donors; 4) evaluation of renal artery aneurysms (uncommon), aneurysms extending to the renal arteries or dissection of the aorta. It is also effective, but only slightly superior to conventional CT, in depicting thrombosis or tumor invasion of renal veins, although it is highly effective in evaluating anatomical variations and renal vein anomalies. In inflammatory vascular disease it is similar to catheter angiography, although its impact is not considerable due to the low prevalence of inflammatory vascular disease in our setting.

Arteriovenous fistula secondary to iliac mycotic aneurysm: helical CT findings.

We describe the case of a 59-year-old man who presented a mycotic aneurysm of the common right iliac artery due to Streptococcus agalactiae and developed an arteriovenous fistula within the inferior vena cava secondary to spontaneous rupture of the aneurysm. The clinical syndrome, helical computed tomographic, and angiographic findings are described and discussed.

Portomesenteric vein gas: pathologic mechanisms, CT findings, and prognosis.

Portomesenteric vein gas is a rare condition whose pathogenesis is not fully understood. Portomesenteric vein gas is most commonly caused by mesenteric ischemia but may have a variety of other causes. The primary factors that favor the development of this pathologic entity are intestinal wall alterations, bowel distention, and sepsis. Portomesenteric vein gas is idiopathic in approximately 15% of cases. Advanced imaging techniques such as computed tomography (CT) have increased the sensitivity for detection of portomesenteric vein gas. At CT, portal vein gas appears as tubular areas of decreased attenuation in the liver, predominantly in the left lobe. Gas in the great mesenteric veins can easily be demonstrated with contrast material-enhanced CT, whereas gas in the small mesenteric veins appears as tubular or branched areas of decreased attenuation in the mesenteric border of the bowel. Findings of portomesenteric vein gas at CT should be carefully evaluated in the context of clinical findings. In the majority of cases, the prognosis is favorable and surgery is not required. However, when CT demonstrates portomesenteric vein gas and clinical findings suggest the presence of mesenteric ischemia, surgery is mandatory.

Complications of orthotopic liver transplantation: spectrum of findings with helical CT.

Orthotopic liver transplantation has become the treatment of choice for patients with end-stage nonmalignant liver disease. The surgical techniques and immunosuppressive therapy for this procedure have improved considerably. Nevertheless, there are still significant complications, particularly those of vascular origin, which can lead to graft failure and require retransplantation unless prompt treatment is instituted. These complications include arterial and venous thrombosis and stenosis; arterial pseudoaneurysm; biliary leakage, stricture, and obstruction; liver ischemia, infarction, and abscess; fluid collections and hematomas; lymphoproliferative disorders; recurrent tumors; hepatitis C virus infection; and splenic infarction. Since the clinical presentation of posttransplantation complications is frequently nonspecific and varies widely, imaging studies are critical for early diagnosis. Helical computed tomography (CT) is a valuable complement to ultrasonography (US) in the postoperative period and is a safe, accurate, and noninvasive method of demonstrating hepatic vessels (hepatic artery, portal vein, hepatic veins, and inferior vena cava) and evaluating nonvascular complications (in the hepatic parenchyma and bile duct abnormalities) and extrahepatic tissues. Knowledge and early recognition of these complications is essential for graft salvage, and CT can provide valuable information, particularly for patients with indeterminate US results or in whom US examination is difficult.

[The radiologic manifestations of bronchiolitis obliterans]. / Manifestaciones radiológicas de la bronquiolitis obliterante.

We reviewed the radiological findings in 19 patients suffering obliterans bronchiolitis, all of whom were classified as idiopathic obliterans bronchiolitis with organizing pneumonia. In most cases, above 80%, X-rays showed alveolar opacities in patches; other less frequent findings were the presence of an interstitial pattern and cavitation (10%). Radiological findings are not specific being most useful in posttreatment patient follow-up.

Duodenal schwannoma causing gastrointestinal bleeding: helical CT findings.

Neurogenic tumors of the small intestine are extremely rare and represent an unusual cause of gastrointestinal hemorrhage. We present a case of schwannoma of the fourth portion of the duodenum demonstrated by helical computed tomography. Multiplanar reconstructions showed a hypervascular tumor arising from the inferior wall of the duodenum. The use of water as oral contrast agent instead of iodinated contrast permitted a better visualization of the intact mucosa and differentiated a hypervascular tumor from hypodense gastrointestinal content.

CT evaluation of underlying cause in spontaneous subcapsular and perirenal hemorrhage.

We evaluated the CT scans of 13 patients with spontaneous subcapsular or perinephric hemorrhage (SPH) associated with these underlying causes: 4 angiomyolipomas, 2 renal cell carcinomas, 1 renal metastatic malignant melanoma, 1 ruptured renal artery aneurysm, 1 adrenal myelolipoma, 1 ruptured renal abscess, 2 ruptured hemorrhagic cysts, and 1 patient with undiagnosed coagulation disorder. Our objective was to ascertain whether an underlying cause of SPH was identifiable by CT, and to determine the extension of the hematomas. Computed tomography identified the hematoma in all 13 cases (sensitivity 100 %). In all 12 cases in which there was a renal or adrenal anatomic lesion, the underlying cause was identified with CT (100 %), with correct diagnosis in 11 cases (91.6 %). The case in which no lesion was identified was the undiagnosed coagulation disorder. We conclude that CT is a useful technique for the initial evaluation of SPH, permitting diagnosis of hemorrhage and identification of the underlying cause.

Small bowel obstruction secondary to bezoar: CT diagnosis.

Two cases of small bowel obstruction secondary to phytobezoar diagnosed by computed tomography (CT) and confirmed at surgery are presented. CT findings were dilated intestinal loops and an intraluminal mass with air bubbles retained in its interstices, resulting in a mottled appearance. We propose that definite diagnosis of small bowel bezoar can be made on the basis of these CT findings.

Improved diagnosis of hepatic perfusion disorders: value of hepatic arterial phase imaging during helical CT.

The liver has a unique dual blood supply, which makes helical computed tomography (CT) a highly suitable technique for hepatic imaging. Helical CT allows single breath-hold scanning without motion artifacts. Because of rapid image acquisition, two-phase (hepatic arterial phase and portal venous phase) evaluation of the hepatic parenchyma is possible, improving tumor detection and tumor characterization in a single CT study. The arterial and portal venous supplies to the liver are not independent systems. There are several communications between the vessels, including transsinusoidal, transvasal, and transplexal routes. When vascular compromise occurs, there are often changes in the volume of blood flow in individual vessels and even in the direction of blood flow. These perfusion disorders can be detected with helical CT and are generally seen as an area of high attenuation on hepatic arterial phase images that returns to normal on portal venous phase images; this finding reflects increased arterial blood flow and arterioportal shunting in most cases. Familiarity with the helical CT appearances of these perfusion disorders will result in more accurate diagnosis. By recognizing these perfusion disorders, false-positive diagnosis (hypervascular tumors) or overestimation of the size of liver tumors (eg, hepatocellular carcinoma) can be avoided.

Scintigraphy, angiography and computed tomography in unilateral hyperlucent lung due to obliterative bronchiolitis.

This study examines the value of different imaging methods in assessing the anatomic structures of unilateral hyperlucent lung due to obliterative bronchiolitis. We studied 9 patients, 5 males and 4 females, suffering from UHL (mean age 49 years). Ventilation-perfusion scan (VPS) and computed tomography (CT) of the chest were performed in all, and conventional angiography or digital substraction angiography (DSA) in 7 patients. The VPS showed the characteristic pattern of a matched ventilation-perfusion defect and considerable air trapping during the washout phase. Conventional angiography and DSA displayed a smaller pulmonary artery on the affected side, with a poor peripheral vasculature. CT displayed a loss of lung volume in all cases, with diminished mean attenuation values, a markedly diminished vasculature and integrity of the main airways. In contrast to other imaging modalities, CT imaged bronchiectasis, which was the cause of the patients' clinical symptoms of bronchorrhea and hemoptysis. We conclude that CT of the chest is the most valuable imaging method for evaluating unilateral hyperlucent lung, particularly in symptomatic patients.

Psoas muscle pancreatic pseudocyst: CT--US diagnosis and percutaneous drainage.

We present 2 cases of psoas muscle pancreatic pseudocysts. In both cases there was no clinical or laboratory evidence of recent acute pancreatitis. The route of extension for the pseudocyst from the pancreas to the psoas was the perirenal space. In both cases the diagnosis was made on the basis of imaging studies and the pseudocysts resolved with percutaneous drainage only.

Spontaneous aortocaval fistula: CT findings with pathologic correlation.

We present a case of aortocaval fistula (ACF) secondary to spontaneous rupture of an atherosclerotic infrarenal aortic aneurysm into the inferior vena cava that was initially diagnosed with computed tomography (CT). This is believed to be the first report of this condition with CT demonstration of the exact site of fistula and CT-pathologic correlation. We retrospectively reviewed the CT findings of another two cases of ACF and the previous literature.

Spontaneous duodenal fistula due to hepatic hydatid cyst.

Communication of a hepatic hydatid cyst to the duodenum appears to be extremely rare. This is the first case described in the imaging literature of hepatic echinococcosis fistulized to the duodenum studied by computed tomography.

CT of primary bilateral adrenal lymphoma.

Two cases of bilateral primary adrenal lymphoma are presented. One case had a cystic appearance and the other a homogeneous density.

Aortic dissection: diagnosis and follow-up with helical CT.

Acute aortic dissection is a cardiovascular emergency that requires prompt diagnosis and treatment. Helical computed tomography (CT) allows diagnosis of acute aortic dissection with a sensitivity and specificity of nearly 100%. With helical CT, a dissection involving the ascending aorta (type A in the Stanford classification) can be differentiated from one distal to the left subclavian artery (type B). Helical CT can also be used to identify atypical forms of aortic dissection such as intramural hematoma, penetrating atherosclerotic ulcer, ruptured type B dissection, and atypical configurations of the intimal flap. Helical CT is useful in follow-up of aortic dissection by allowing assessment of early and late changes after surgery or medical treatment. Such changes include postoperative complications of type A dissection, healing of intramural hematoma, progression of intramural hematoma, and aneurysms of the true or false lumen. Helical CT can also be used to monitor potentially life-threatening ischemic complications of abdominal branch vessels.