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Biomedical subjects

A Blachar

Publications and source records attributed to A Blachar.

At least 19 recordsLinked to original sources
PubMed2001

CT evaluation of the liver: principles and techniques.

Technical advances within the past decade have dramatically improved the diagnostic capabilities of CT, primarily due to helical CT scanners coupled with mechanical injectors for i.v. administration of contrast media. There is no such thing as a generic "abdominal CT scan"; rather, specific protocols should be utilized for optimal detection and characterization of hepatic masses (or other suspected pathologic processes). Multiphasic CT protocols are especially important for detecting hypervascular liver tumors. We present the principles and rationale for various CT protocols along with some of the common pitfalls. Understanding this background material will allow the reader to better understand subsequent articles dealing with specific applications of CT and other abdominal imaging techniques.

Contrast Media↗
PubMed2001

Radiologist performance in the diagnosis of internal hernia by using specific CT findings with emphasis on transmesenteric hernia.

PURPOSE: To evaluate the performance of radiologists in the diagnosis of internal hernia with specific computed tomographic (CT) findings. MATERIALS AND METHODS: Abdominal CT scans obtained in 42 patients were retrospectively reviewed by three radiologists. The case group consisted of 18 patients with internal hernias (two paraduodenal, 16 transmesenteric); the comparison group was 24 patients with no internal hernia. Images were reviewed in a random and blinded fashion. Individual and group performance was evaluated with receiver operating characteristic (ROC) analysis, and interobserver agreement was measured with Cronbach coefficient alpha. Individual CT signs relevant as predictors of transmesenteric hernia were identified with logistic regression analysis and ranked by their odds ratio and P values. RESULTS: Both paraduodenal hernias were diagnosed by all readers on the basis of CT signs, including a retrogastric saclike mass of small-bowel loops. Diagnosis of transmesenteric hernia was more difficult and variable, with an average accuracy of area under the ROC curve (A(z)) of 77%, sensitivity of 63%, and specificity of 76%. CT signs of transmesenteric hernia were recognized consistently (Cronbach coefficient alpha >or= 0.80) and included a cluster of dilated small-bowel segments and stretching and displacement of mesenteric vessels. Coexisting volvulus and ischemia were diagnosed with low sensitivity (46% and 43%, respectively) but high specificity (96% and 98%, respectively). CONCLUSION: Diagnosis of internal hernia with CT remains difficult. Special attention should be given to the clustering of bowel loops, the mesenteric vessels, and signs of small-bowel obstruction.

Adolescent↗
PubMed2001

Internal hernia: clinical and imaging findings in 17 patients with emphasis on CT criteria.

PURPOSE: To review the clinical and radiologic features of internal hernia and to derive useful radiographic and CT criteria to assist in diagnosis. MATERIALS AND METHODS: Retrospective review of medical records revealed 17 patients with surgically proved internal hernia (three paraduodenal, 14 transmesenteric) who had 15 computed tomographic (CT) scans and three small-bowel follow-through (SBFT) images. RESULTS: CT signs common to all types of internal hernia included evidence of small-bowel obstruction; clustering of small bowel; stretched, displaced, crowded, and engorged mesenteric vessels; and displacement of other bowel segments, especially the transverse colon and fourth portion of the duodenum. Left-sided paraduodenal hernias demonstrated a sac-like mass of small-bowel loops interposed between the stomach and pancreatic tail and a posterior mass effect on the stomach. All three paraduodenal hernias were diagnosed confidently at retrospective review of CT and SBFT findings. Transmesenteric hernias demonstrated clustered small-bowel loops adjacent to the abdominal wall without overlying omental fat and central displacement of colon and were frequently complicated by small-bowel volvulus (five of 14) and bowel ischemia (six of 14). CT demonstrated signs of volvulus in four of six patients with ischemia. CT findings considered definitive or suggestive of internal hernia were demonstrated in 15 patients. CONCLUSION: Internal hernia is an important and underdiagnosed condition. Transmesenteric hernia is most common in our experience and is usually related to prior abdominal surgery, especially with creation of a Roux-en-Y anastomosis. CT may allow confident diagnosis in most patients.

Adult↗
PubMed2001

Bowel obstruction following liver transplantation: clinical and ct findings in 48 cases with emphasis on internal hernia.

PURPOSE: To review the incidence, cause, and radiologic findings of bowel obstruction in patients who have undergone orthotopic liver transplantation (OLT). MATERIALS AND METHODS: Retrospective review of 4,001 cases of OLT revealed 48 cases of bowel obstruction in 44 patients. Seventeen computed tomographic (CT) scans and seven barium-enhanced radiographs were reviewed to determine level and cause. Surgical proof was available in 45 cases, while three had characteristic clinical and radiographic features. RESULTS: Adhesions caused the obstruction in 19 cases in 16 patients; three had bowel ischemia. Internal hernias caused obstruction in 18 patients; all obstructions were transmesenteric or retroanastomotic and occurred with choledochoenteric anastomosis. Seven patients had volvulus; four had bowel ischemia. CT signs of internal hernia included mesenteric vascular abnormalities and clusters of dilated small-bowel segments that displaced the colon away from the abdominal wall. Prospective diagnosis of internal hernia was made in only one case. Incisional or inguinal hernia caused obstruction in seven patients; CT was used just once. Four patients had neoplastic bowel obstruction, three due to posttransplantation lymphoproliferative disorder and one due to colon carcinoma. CONCLUSION: Liver transplantation was complicated by bowel obstruction in 48 (1.2%) of 4,001 cases. While adhesions and incisional hernias are common and well recognized, other causes are more challenging to diagnose. The CT findings reported here may allow more accurate diagnosis of internal hernia.

Colonic Neoplasms↗
PubMed2001

Focal nodular hyperplasia: CT findings with emphasis on multiphasic helical CT in 78 patients.

PURPOSE: To evaluate features of focal nodular hyperplasia (FNH) at multiphasic helical computed tomography (CT). MATERIALS AND METHODS: Clinical, pathologic, and preoperative imaging findings were retrospectively reviewed in 78 patients. Conventional liver CT was performed in nine patients; helical multiphasic CT, in 69. Diagnosis was based on complete resection (n = 20), biopsy (n = 42), or clinical and imaging follow-up for a minimum of 6 months (n = 16). Number, size, location, margins, surface, homogeneity of enhancement, and presence of a central scar, mass effect, exophytic growth, calcification, pseudocapsule, or vessels feeding or draining the lesion were evaluated. RESULTS: CT depicted 124 tumors (mean diameter, 4.1 cm; range, 1-11 cm); 62 were small (< or =3 cm). FNHs were hypervascular and hyperattenuating to liver on 106 of 106 arterial phase scans and were isoattenuating to liver on 82 of 89 delayed scans. Of the 124 tumors, 111 enhanced homogeneously, 109 had a smooth surface, 101 were subcapsular, 89 had ill-defined margins, and 62 had a central scar that was observed more often in large lesions (40 of 62 lesions) than in small lesions (22 of 62 lesions). FNHs less frequently exerted a mass effect (43 lesions), had vessels around or within the lesion (42 lesions), demonstrated exophytic growth (40 lesions), or showed a pseudocapsule (10 lesions). Only one FNH had calcification. CONCLUSION: Helical CT demonstrates characteristic features that may allow confident diagnosis of FNH. In typical cases, neither biopsy nor further imaging is necessary.

Adolescent↗
PubMed2001

Hemangioma in the cirrhotic liver: diagnosis and natural history.

PURPOSE: To investigate the natural history and diagnosis of cavernous hemangioma in the cirrhotic liver with computed tomography (CT) and magnetic resonance (MR) imaging. MATERIALS AND METHODS: Imaging and pathologic findings of 21 hemangiomas in 17 patients were retrospectively reviewed. CT of the liver was performed in all patients; MR imaging, in four. Cirrhosis was confirmed histologically in all patients, and the diagnosis of hemangioma was based on histopathologic findings (15 patients, 18 hemangiomas) or strict imaging criteria (two patients, three hemangiomas). Ten patients underwent imaging follow-up. The number, sizes, location, attenuation, pattern of enhancement, exophytic growth, presence of capsular retraction, and size stability were evaluated. RESULTS: Of the 21 hemangiomas, five were not detected at CT or MR imaging. Twelve (75%) of 16 hemangiomas were subcapsular, two (12%) of 16 demonstrated exophytic growth, 14 (87%) of 16 demonstrated nodular peripheral enhancement, and 16 (100%) of 16 were isoattenuating to blood vessels. At MR imaging, all five hemangiomas demonstrated nodular peripheral enhancement and hyperintensity on T2-weighted images. Seven lesions were smaller at follow-up, and five lesions developed retraction of the hepatic capsule. CONCLUSION: Even within the cirrhotic liver, larger hemangiomas can usually be diagnosed confidently with CT or MR imaging. With progressive cirrhosis, however, hemangiomas are likely to decrease in size, become more fibrotic, and are difficult to diagnose radiologically and pathologically.

Adult↗
PubMed2001

Primary biliary cirrhosis: clinical, pathologic, and helical CT findings in 53 patients.

PURPOSE: To evaluate and compare clinical, pathologic, and helical computed tomographic (CT) findings of primary biliary cirrhosis (PBC). MATERIALS AND METHODS: The authors reviewed the medical records and CT scans of 53 patients who underwent evaluation, treatment, and orthotopic liver transplantation (OLT) at their institution. All patients underwent helical multiphase CT (total, 98 abdominal CT scans; range, one to five scans per patient). Multiple epidemiologic, clinical, and morphologic criteria were evaluated. Advanced disease was defined as hepatic insufficiency leading to OLT within the subsequent 2 years. Clinical and morphologic features were evaluated and compared in the advanced and less advanced cases of PBC. RESULTS: Common and characteristic findings included the following: 45 (85%) of the 53 patients were women with the onset of disease (diagnosis) in middle age (mean, 50.7 years; range, 26-71 years). The average time from diagnosis to OLT was 6.1 years (range, 1.5-20.0 years). CT findings in advanced PBC often resembled those seen in other forms of cirrhosis, with a small heterogeneously attenuating liver, varices, and splenomegaly. The liver in less advanced disease was usually enlarged or normal in size, with a smooth contour, little atrophy, and lacelike fibrosis and regenerative nodules in nearly one-third of the livers. Patients with less advanced disease frequently had varices (n = 33 [62%]) and ascites (n = 13 [24%]). Lymphadenopathy was seen in 47 (88%) patients. Hepatocellular carcinoma was found in four (8%) patients, two of whom also had chronic hepatitis C. During a follow-up period of 5-72 months (median, 46 months; mean, 42 months) after OLT, only two patients experienced recurrence of PBC. CONCLUSION: PBC is an important cause of liver failure, with distinctive clinical and CT findings that may assist diagnosis and allow adequate treatment. CT can demonstrate varices and ascites before frank cirrhosis is evident and can help evaluate the progression of the disease.

Adult↗
PubMed2000

Preoperative localization of parathyroid adenoma in patients with concomitant thyroid nodular disease.

We have previously demonstrated the role of high-resolution ultrasonography (US) in preoperative localization of parathyroid adenoma in patients with primary hyperparathyroidism (PHPT) and no thyroid abnormalities. The present study prospectively evaluated the possible additional value of 99mTc-sestamibi (MIBI) in patients with PHPT and concomitant multinodular thyroid disease (MND). Patients with PHPT underwent US and MIBI scintigraphy prior to neck exploration. Imaging data were correlated with the site and pathology of the parathyroid tissue removed and were analyzed separately for patients with MND and those with a normal thyroid gland. Among 77 patients with a solitary parathyroid adenoma at surgery, 40 had concomitant MND, whereas 37 patients had no morphologic changes in the thyroid gland, on US or at surgery. Prior to surgery, MIBI scintigraphy depicted 58 of the 77 adenomas (75%) and US localized 51 (66%): the combined sensitivity was 87% (67/77). Among the 37 patients with no thyroid nodules, MIBI located 29 (78%) and US identified 30 (81%) of the adenomas; the combined sensitivity was 89%. In the 40 patients with MND, MIBI identified 29 adenomas (73%) and US localized only 53% (21/40); the combined sensitivity was 85%. Overall, the positive predictive value (PPV) of MIBI for detecting a solitary parathyroid adenoma was 94%, for US it was 88%, and with the two tests combined it was 97%. In patients with no thyroid abnormalities, the PPV of MIBI and US was 97%, but it decreased to 91% and 78%, respectively, in patients with MND. Two patients with false-positive findings on both MIBI and US had associated thyroid disease. Hence MIBI scintigraphy contributes to localization of a solitary parathyroid adenoma mainly in patients with concomitant MND. The combined MIBI and US modalities result in sparing these patients bilateral neck exploration.

Adenoma↗
PubMed1997

[Superficial dorsal penile vein thrombosis (Mondor's disease)].

Superficial venous thrombosis of the chest wall was first described by Mondor in 1939. Braun-Falco reported in 1955 superficial penile vein involvement in diffuse thrombophlebitis of the abdominal wall and in 1958 Helm and Hodge first described isolated superficial dorsal penile vein thrombosis. Since then, fewer than 50 cases have been reported. The clinical presentation is usually redness and swelling of the dorsum of the penis, accompanied by a palpable, tender thrombotic vein. This acute and painful disease frightens the patients, who is concerned about his fertility and sexual function. The main cause of this disease is frequent sexual intercourse. Diagnosis is based upon anamnesis, physical examination and penile sonography with color Doppler imaging. It is usually a benign disease which resolves quickly under appropriate medical therapy. We present a man who was admitted for this condition and was successfully treated.

Adult↗
PubMed1994

Clinical outcome and follow-up of prenatal hydronephrosis.

Between 1987 and 1991, 160 hydronephrotic kidneys were diagnosed prenatally and confirmed postnatally in 100 infants. The aim of the study was to describe the natural history and management of primary hydronephrosis detected prenatally. We devised a new classification of obstructive uropathy outcome using ultrasonography and the diethylenetriamine penta-acetic acid scan. Accordingly, we classified the patients as having mild, moderate or severe hydronephrosis. Nine patients had pyeloplasties and 5 had ureteric reimplantations. We conclude that in most cases there is no need for immediate surgery, and that the initial approach to the management of congenital hydronephrosis should be conservative. We suggest that anti-bacterial prophylaxis be conventionally given to infants with vesicoureteral reflux and for the first 6 months of life to infants demonstrating moderate to severe newborn primary hydronephrosis.

Female↗
PubMed1994

Evaluation of prenatally diagnosed hydronephrosis by morphometric measurements of the kidney.

A large number of hydronephrotic kidneys (108) were diagnosed prenatally in 69 infants between 1987 and 1991 and subsequently confirmed postnatally. Prenatal morphometric measurements were done in order to find reliable parameters for the detection of a group at risk for surgical treatment. A second aim of the study was to describe the natural history and management of hydronephrosis detected prenatally. We devised a classification of postnatal obstructive uropathy using ultrasonography and the renal scan. Accordingly, we classified the patients as having mild, moderate or severe hydronephrosis. A renal pelvic antero-posterior diameter (APD) of 9 mm or more, and a pelvic-to-renal APD ratio of 0.45 before 32 weeks of gestation and 0.52 thereafter, were found to be useful for the detection of severe outcome. Our new parameter, a pelvic-to-renal volume ratio of greater than 0.08, can also be used for this purpose.

Algorithms↗