Perigastric appendagitis: CT and clinical features in eight patients.

AIM: To describe perigastric appendagitis (PA) on CT as a new and distinct clinical entity to enable recognition and prevent additional unnecessary investigation or intervention. MATERIALS AND METHODS: Institutional review board approval was obtained and informed consent was waived. Retrospective review of the clinical data and CT findings in eight patients with PA encountered over 10 years at one institution was performed. The English literature was reviewed and summarized. Two experienced abdominal radiologists reviewed the CT images by consensus. RESULTS: Seven of eight patients had moderate to severe epigastric pain for 1­7 days. All eight patients (four men, four women; mean age 44 years, range 33­81 years) had no fever or leukocytosis. All underwent abdominal CT which showed ovoid fat inflammation along the course of the perigastric ligaments (gastrohepatic, gastrosplenic, and falciform). Two had gastric wall thickening. Although the inflammation was correctly described, the specific diagnosis was not made on initial interpretation in five patients. Subsequently, they underwent further diagnostic testing [an upper gastrointestinal examination and hepatobiliary iminodiacetic acid (HIDA) cholescintigraphy, an upper endoscopy and MRI examination, HIDA cholescintigraphy, another CT, and an MRI examination, respectively]. The HIDA cholescintigraphy, upper GI examination, and upper endoscopy examinations were normal. No repeated examination was performed on the other three patients. Pain resolved spontaneously in all within two days. CONCLUSION: Perigastric appendagitis can present with an acute abdomen, which is safely managed conservatively if diagnosed correctly. Radiologists should be aware of the entity to avoid unnecessary intervention, and recognize the CT findings of ovoid fat inflammation in the distribution of the perigastric ligaments.

Structure determination of aquomet porcine hemoglobin at 2.8 A resolution.

Considerable attention is currently focused on hemoglobins from lower mammals, such as the pig, for potential use in cell-free blood substitute preparations safe for use in humans. As the first step in the elucidation of structure-function relationships in porcine hemoglobin, we have determined the three-dimensional structure of aquomet porcine hemoglobin at 2.8 A resolution. Overall, the porcine hemoglobin tetramer is structurally similar to that of human oxyhemoglobin, and the r.m.s. deviation of all backbone atoms (minus five residues at the amino and carboxyl termini of each subunit) is 0.8 A. This similarity is not unexpected given that human and porcine hemoglobins exhibit 85% sequence identity. However, regions of subtle structural differences are implicated in subtle functional differences between the two proteins, such as the 20 to 25% inhibition of the alkaline Bohr effect and the accompanying reduction in oxygen-linked chloride binding observed for porcine hemoglobin. The structural similarity of these two mammalian hemoglobins also rationalizes the novel hybridization behavior of pig and human subunits in transgenic pigs expressing both porcine and human hemoglobins in porcine erythrocytes.

Clostridium perfringens emphysematous cystitis.

Emphysematous cystitis is a rare disease and is usually caused by aerobic bacteria, most commonly Escherichia coli. Only rarely have anaerobic bacteria been associated with this condition. We report a case of emphysematous cystitis due to Clostridium perfringens with bacteremia in an elderly diabetic woman.

Mycobacterium bovis vertebral osteomyelitis and psoas abscess after intravesical BCG therapy for bladder carcinoma.

Systemic complications of intravesicular BCG for bladder carcinoma are uncommon, and include fever, pneumonia, hepatitis, arthralgias, or skin rash. Local complications of BCG therapy for bladder cancer include cystitis, prostatitis, epididymo-orchitis, granulomatous lymphadenitis, or ureteral obstruction. We believe this is the first case of Mycobacterium bovis vertebral osteomyelitis and psoas abscess complicating intravesicular BCG therapy for bladder carcinoma.

Alternative or additional diagnoses on unenhanced helical computed tomography for suspected renal colic: experience with 1000 consecutive examinations.

OBJECTIVES: To determine the incidence and spectrum of significant alternative or additional diagnoses established or suggested on unenhanced helical computed tomography (CT) in a large series of patients with suspected renal colic. METHODS: One thousand consecutive unenhanced helical CT examinations were performed for suspected renal colic. All official CT reports were retrospectively reviewed, which was followed by review of all available relevant follow-up radiology reports. A selected image and chart review was also performed. RESULTS: Ureteral calculi were identified on 557 examinations, findings consistent with a recently passed stone were discovered on 67 examinations, and 275 CT examinations were unremarkable. An alternative or additional diagnosis was established or suggested on 101 examinations, including in 26 patients with concurrent ureteral calculi. There were 62 genitourinary and 39 nongenitourinary tract diagnoses. Eighty-seven of the diagnoses could be confirmed on retrospective image review combined with patient follow-up. There were two false-positive diagnoses for significant, alternative pathologic findings. CONCLUSIONS: A wide spectrum of significant, alternative, and additional genitourinary and nongenitourinary diagnoses can be reliably established or suggested on unenhanced helical CT performed for suspected renal colic. These abnormalities were identified in 10% of cases in this series of 1000 consecutive CT examinations.

Sinus histiocytosis with massive lymphadenopathy: a case of simultaneous upper respiratory tract and CNS disease without lymphadenopathy.

The authors describe a 20-year-old man who initially developed an intradural mass in the upper cervical region and subsequently presented with nasal/paranasal sinus and posterior fossa masses, well demonstrated by CT and MR. Histopathology demonstrated dense fibrous tissue, aggregates of histiocytes with round to oval vesicular nuclei, and other features diagnostic of Rosai-Dorfman disease; a right nasal biopsy prior to surgery showed similar microscopic findings.

Gangliocytoma of the cervicothoracic spinal cord.

We present a case of an extensive cervicothoracic gangliocytoma in an asymptomatic 9-year-old boy with progressive scoliosis. MR findings were that of a moderately enhancing cervicothoracic intramedullary mass, which throughout most of its length could not be distinguished from the normal spinal cord.

Radiology of pneumonia.

Chest radiography is the imaging technique of choice in evaluating patients with suspected pneumonia because of its low radiation dose, low cost, and wide accessibility. In daily practice, radiographs are used to confirm the clinical diagnosis of pneumonia, characterize the extent and severity of disease, search for complications such as empyema, monitor the response to therapy, and examine for possible alternative or additional diagnoses. Although CT scan has no defined role in the routine assessment of patients with either community-acquired or nosocomial pneumonias, its advantages of superior contrast resolution and cross-sectional display can often be helpful in the analysis of complex cases, particularly when radiographic evidence of associated central obstruction, cavitation, lymphadenopathy, or empyema is equivocal. In the immunocompromised patient population, high-resolution CT has been shown to be more sensitive than plain film radiography in the early detection of pulmonary infections.

DNA adduct formation by 12 chemicals with populations potentially suitable for molecular epidemiological studies.

DNA adduct formation, route of absorption, metabolism and chemistry of 12 hazardous chemicals are reviewed. Methods for adduct detection are also reviewed and approaches to sensitivity and specificity are identified. The selection of these 12 chemicals from the Environmental Protection Agency list of genotoxic chemicals was based on the availability of information and on the availability of populations potentially suitable for molecular epidemiological study. The 12 chemicals include ethylene oxide, styrene, vinyl chloride, epichlorohydrin, propylene oxide, 4,4'-methylenebis-2-chloroaniline, benzidine, benzidine dyes (Direct Blue 6, Direct Black 38 and Direct Brown 95), acrylonitrile and benzyl chloride. While some of these chemicals (styrene and benzyl chloride, possibly Direct Blue 6) give rise to unique DNA adducts, others do not. Potentially confounding factors include mixed exposures in the work place, as well the formation of common DNA adducts. Additional research needs are identified.

Initial results for automated computational modeling of patient-specific electromagnetic hyperthermia.

Developments in finite-difference time-domain (FD-TD) computational modeling of Maxwell's equations, super-computer technology, and computed tomography (CT) imagery open the possibility of accurate numerical simulation of electromagnetic (EM) wave interactions with specific, complex, biological tissue structures. One application of this technology is in the area of treatment planning for EM hyperthermia. In this paper, we report the first highly automated CT image segmentation and interpolation scheme applied to model patient-specific EM hyperthermia. This novel system is based on sophisticated tools from the artificial intelligence, computer vision, and computer graphics disciplines. It permits CT-based patient-specific hyperthermia models to be constructed without tedious manual contouring on digitizing pads or CRT screens. The system permits in principle near real-time assistance in hyperthermia treatment planning. We apply this system to interpret actual patient CT data, reconstructing a 3-D model of the human thigh from a collection of 29 serial CT images at 10 mm intervals. Then, using FD-TD, we obtain 2-D and 3-D models of EM hyperthermia of this thigh due to a waveguide applicator. We find that different results are obtained from the 2-D and 3-D models, and conclude that full 3-D tissue models are required for future clinical usage.

Pulmonary artery laceration and tension pneumothorax in blunt chest trauma.

Traumatic laceration of the pulmonary artery is rare and is associated with a high mortality rate. The article describes a patient with pulmonary artery laceration from blunt chest trauma who presented with tension pneumothorax. Potentially life-threatening intrathoracic bleeding was not apparent until the pneumothorax was decompressed.

Calcification in untreated mediastinal Hodgkin's lymphoma.

Calcification is very rarely reported in untreated thoracic lymphoma. However, calcification can occur (although uncommonly) in lymphoma following chemotherapy or radiation, and in areas of scaring or fibrous healing. The authors describe the case of a pregnant woman with a large mediastinal mass that contained calcifications visible on both chest radiography and thoracic computed tomography, which proved to be Hodgkin's lymphoma.

Pleuropulmonary blastoma simulating an empyema in a young child.

Pleuropulmonary blastoma is a rare childhood malignancy that may simulate an empyema both clinically and radiographically. A 3-year-old boy with fever, cough, and abdominal pain developed complete opacification of the left hemithorax with contralateral mediastinal shift over the course of several weeks. At thoracotomy, a pleuropulmonary blastoma was discovered. The radiology, pathology, and clinical course of this rare neoplasm are discussed.

Unenhanced CT of abdominal and pelvic hemorrhage.

CT performed without oral or intravenous contrast is the initial imaging study of choice in many situations for the detection of hemorrhage anywhere in the abdomen and pelvis. The presence or absence of hemorrhage can be determined rapidly, and the amount and precise location of hemorrhage can also be evaluated. This article reviews the appearances and the common and unusual etiologies of abdominal and pelvic hemorrhage on unenhanced CT. The role of intravenous contrast-enhanced CT in patients with known or suspected abdominal and pelvic hemorrhage is also examined.

Massive renal angiomyolipoma in tuberous sclerosis.

A massive renal angiomyolipoma, measuring 45 x 20 x 15 cm and weighing 3,500 g in a patient with tuberous sclerosis is presented. While renal angiomyolipomas may become quite large, this is one of the largest such tumors ever reported.

Splenic hemangioma. Detection on a technetium-99M MDP bone scan.

While relatively rare, the most common benign tumor of the spleen is the hemangioma. We report a case of a noncalcified splenic hemangioma found incidentally on a technetium-99m methylene diphosphonate (Tc-99m MDP) bone scan. Tc-99m MDP may have been accumulated by iron, which was deposited extensively within the hemangioma.

Pneumorachis and pneumocephalus caused by pneumothorax and multiple thoracic vertebral fractures.

Pneumorachis, or air within the spinal canal, has rarely been described, particularly in conjunction with thoracic trauma. We report a case of pneumorachis and pneumocephalus in a patient with a tension pneumothorax and multiple closed thoracic spinal fractures.

A rare case of cerebellar glioblastoma multiforme in childhood: MR imaging.

Glioblastoma multiforme is a highly malignant brain neoplasm that is very rarely discovered in childhood but accounts for approximately 17% of intracranial tumors in the adult. Only approximately 25 children with glioblastoma multiforme in the cerebellum have been described in the literature. We report on a 4 1/2-year-old girl with this tumor in the cerebellar hemisphere and discuss the magnetic resonance imaging findings.

Perinephric xanthogranulomatosis: CT diagnosis and confirmation by CT-guided percutaneous biopsy.

Xanthogranulomatosis is an idiopathic, rare process in which lipid-laden histiocytes may deposit in various locations in the body, which if systemic is called Erdheim-Chester disease. A rare case of isolated retroperitoneal, bilateral perinephric xanthogranulomatosis is reported. The diagnosis was suspected on cross-sectional imaging and was confirmed by CT-guided percutaneous core biopsy.