PubMed Health⌕ Search

Biomedical subjects

Ihab R Kamel

Publications and source records attributed to Ihab R Kamel.

At least 19 recordsLinked to original sources
PubMed2006

Diagnosis of primary sclerosing cholangitis: a blinded comparative study using magnetic resonance cholangiography and endoscopic retrograde cholangiography.

BACKGROUND: We hypothesized that magnetic resonance cholangiography (MRC) may have less accuracy for the diagnosis and the assessment of the severity of primary sclerosing cholangitis (PSC) than endoscopic retrograde cholangiography (ERC). OBJECTIVE: The aim of this study was to determine the diagnostic accuracy and interobserver agreement of both ERC and MRC in PSC. DESIGN: A case-control study. SETTING: University Hospital. PATIENTS: ERCs and MRCs of 36 patients with PSC and 51 controls (normal/other biliary tract diseases) were read in an independent, blinded, and random fashion by 2 magnetic resonance radiologists and 2 interventional endoscopists by using a previously validated classification system. Readers had no access to clinical history, laboratory results, or patient mix. RESULTS: Extrahepatic ductal (EHD) and intrahepatic ductal (IHD) visualization was excellent in 64% of 66% of MRCs and 86% of 74% of ERCs. Sensitivity and specificity for diagnosis of PSC for readers 1 to 4 were 91% and 85%, 88% and 90%, 81% and 96%, and 83% and 96%. respectively. Receiver operating curve values were excellent for all readers (all >0.9). Interobserver agreement (kappa statistics) for the diagnosis of PSC (MRC, 0.83; ERC, 0.73) and for identifying the presence of IHD strictures (MRC, 0.64; ERC, 0.86) was good for both modalities, but only ERC (ERC, 0.55; MRC, 0.36) was good for the presence and the severity of EHD strictures. When assessment of disease severity was limited to the 36 patients with PSC, interobserver agreement was very poor for both MRC (0.23 and 0.07 for EHD and IHD, respectively) and ERC (0.24 and 0.34 for EHD and IHD, respectively). LIMITATIONS: The retrospective case-control study made it difficult to assess the impact of the diagnosis on patient management. CONCLUSIONS: ERC and MRC were comparable for diagnosing PSC, with very good interobserver agreement for the diagnosis of PSC and IHD strictures. Only ERC had good agreement for EHD strictures. Interobserver agreement was very poor for both MRC and ERC when disease severity of PSC was assessed.

Bile Ducts, Extrahepatic↗
PubMed2006

The role of functional MR imaging in the assessment of tumor response after chemoembolization in patients with hepatocellular carcinoma.

PURPOSE: To assess treatment response of hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE) with use of diffusion and dynamic contrast medium-enhanced magnetic resonance (MR) imaging. MATERIALS AND METHODS: MR imaging studies before and after TACE in 38 patients with HCC (33 male patients and five female patients) were evaluated. Diffusion and dynamic contrast medium-enhanced MR imaging was performed on a 1.5-T unit. The imaging protocol included T2-weighted fast spin-echo, breath-hold diffusion-weighted echoplanar, and breath-hold unenhanced and contrast medium-enhanced T1-weighted three-dimensional fat-saturation gradient-recalled echo imaging in the arterial and portal venous phases. Tumor size, percent enhancement, and apparent diffusion coefficient (ADC) values were recorded before and after treatment. Survival analysis was also performed. RESULTS: The study included 38 lesions with a mean diameter of 8.0 cm. Mean reduction in tumor diameter was 8 mm after treatment (t test; P = .0005), which did not fulfill Response Evaluation Criteria in Solid Tumors for complete or partial response. Reduction in tumor enhancement in the arterial (30%) and venous (47%) phases was statistically significant (signed-rank test; P = .0003 and P < 0.00005, respectively). Tumor ADC value increased from 0.0015 mm(2)/sec to 0.0018 mm(2)/sec after treatment (t test; P = .026), whereas the ADC values for the liver, spleen, and muscle remained unchanged. Median patient survival was 19 months. CONCLUSIONS: After TACE, tumors demonstrated decreased size and enhancement with increases in ADC values. In this cohort, diffusion and dynamic contrast medium-enhanced MR imaging parameters were significantly altered after TACE, and these could be useful tools in the assessment of tumor response.

Aged↗
PubMed2006

The use of somatosensory evoked potentials to determine the relationship between patient positioning and impending upper extremity nerve injury during spine surgery: a retrospective analysis.

Somatosensory evoked potential (SSEP) monitoring is used to prevent nerve damage in spine surgery and to detect changes in upper extremity nerve function. Upper extremity SSEP conduction changes may indicate impending nerve injury. We investigated the effect of operative positioning on upper extremity nerve function retrospectively in 1000 consecutive spine surgeries that used SSEP monitoring. The vast majority (92%) of upper extremity SSEP changes were reversed by modifying the arm position and were therefore classified as position-related. The incidence of position-related upper extremity SSEP changes was calculated and compared for five different surgical positions: supine arms out, supine arms tucked, lateral decubitus position, prone arms tucked, and the prone "superman" position. The overall incidence of position-related upper extremity SSEP changes was 6.1%. The lateral decubitus position (7.5%) and prone superman position (7.0%) had a significantly more frequent incidence of position-related upper extremity SSEP changes (P < 0.0001, Z-test for Poisson counts) compared with other positions (1.8%-3.2%). No patient with a reversible SSEP change developed a new postoperative deficit in the affected extremity. SSEP monitoring is of value in identifying and reversing impending upper extremity peripheral nerve injury.

Adolescent↗
PubMed2006

Focal nodular hyperplasia: lesion evaluation using 16-MDCT and 3D CT angiography.

OBJECTIVE: The purpose of this article is to present the imaging features of focal nodular hyperplasia (FNH) using MDCT and 3D CT angiography. CONCLUSION: MDCT with advanced image processing is a powerful tool that may be utilized to identify the imaging features of FNH. These include the presence of large feeding arteries and draining veins, pseudocapsule, central scar, and septations. These features can help in the differentiation of this benign lesion from other hypervascular lesions without the need for additional imaging, biopsy, or surgery.

Adult↗
PubMed2006

Incidental nonneoplastic hypervascular lesions in the noncirrhotic liver: diagnosis with 16-MDCT and 3D CT angiography.

OBJECTIVE: The purpose of this pictorial essay is to review the MDCT features of uncommon hypervascular lesions seen with advanced image processing. CONCLUSION: MDCT with advanced image processing is useful in delineating uncommon hypervascular liver lesions that simulate tumors. Familiarity with the appearance of these lesions may reduce the need for additional imaging, follow-up, and histologic correlation.

Angiography↗
PubMed2005

Distinguishing stress fractures from pathologic fractures: a multimodality approach.

Whereas stress fractures occur in normal or metabolically weakened bones, pathologic fractures occur at the site of a bone tumor. Unfortunately, stress fractures may share imaging features with pathologic fractures on plain radiography, and therefore other modalities are commonly utilized to distinguish these entities. Additional cross-sectional imaging with CT or MRI as well as scintigraphy and PET scanning is often performed for further evaluation. For the detailed assessment of a fracture site, CT offers a high-resolution view of the bone cortex and periosteum which aids the diagnosis of a pathologic fracture. The character of underlying bone marrow patterns of destruction can also be ascertained along with evidence of a soft tissue mass. MRI, however, is a more sensitive technique for the detection of underlying bone marrow lesions at a fracture site. In addition, the surrounding soft tissues, including possible involvement of adjacent muscle, can be well evaluated with MRI. While bone scintigraphy and FDG-PET are not specific, they offer a whole-body screen for metastases in the case of a suspected malignant pathologic fracture. In this review, we present select examples of fractures that underscore imaging features that help distinguish stress fractures from pathologic fractures, since accurate differentiation of these entities is paramount.

Algorithms↗
PubMed2005

Multidetector CT of hepatocellular carcinoma.

Hepatocellular carcinoma is one of the most common causes of cancer death worldwide. Numerous surgical and nonsurgical treatment options are available for the management of patients with HCC. Successful long-term outcome is dependent on early detection of HCC, as well as accurate delineation of the number and location of tumor nodules. We present the different manifestations of hepatocellular carcinoma as depicted by multidetector-row CT with advanced image processing.

Carcinoma, Hepatocellular↗
PubMed2005

Liver and biliary system: evaluation by multidetector CT.

CT commonly is indicated for the evaluation of suspected hepatic and biliary pathology. The recent introduction of multidetector CT (MDCT) provides unique capabilities that are valuable especially in hepatic volume acquisitions, combining short scan times, narrow collimation, and the ability to obtain multiphase data. These features result in improved lesion detection and characterization. Concomitant advances in computer software programs have made three-dimensional applications practical for a range of hepatic image analyses and displays. This article discusses the specific areas of hepatic and biliary pathology where MDCT has a significant diagnostic impact.

Angiography↗
PubMed2005

Distinction of long bone stress fractures from pathologic fractures on cross-sectional imaging: how successful are we?

OBJECTIVE: The objectives of our study were to define CT and MRI features that distinguish pathologic fractures from stress fractures and to compare the performance of CT and MRI with radiography. MATERIALS AND METHODS: Two reviewers retrospectively reviewed 45 MR images, 37 CT scans, and 43 radiographs in 59 patients (30 biopsy-proven pathologic fractures and 29 stress fractures followed to resolution). The features observed on MRI were abnormal bone marrow (well-defined, ill-defined); intracortical, periosteal, or muscle T1 or T2 signal; endosteal scalloping; and a soft-tissue mass. The features seen on CT were marrow abnormality and character (well-defined, ill-defined, permeative, moth-eaten), endosteal scalloping, periosteal reaction (benign, aggressive), and a soft-tissue mass. Reviewers rated their confidence for diagnosing a pathologic fracture on a 1-3 scale (< 50%, 50-95%, > 95% sure, respectively) with each technique. Performance of each technique was defined by reviewer accuracy and area under the receiver operating characteristic curve (Az); the frequency with which the MRI and CT features were associated with pathologic and stress fractures was calculated. RESULTS: For both reviewers, accuracy for differentiating pathologic from stress fractures was highest on MRI (accuracy/Az: reviewer 1, 98%/0.97; reviewer 2, 93%/0.99); CT (reviewer 1, 88%/0.83; reviewer 2, 82%/0.90) was less accurate than radiography (reviewer 1, 94%/0.98; reviewer 2, 88%/0.96). On MRI, pathologic fractures compared with stress fractures exhibited well-defined T1 marrow signal (83% vs 7%, respectively; p < 0.001), endosteal scalloping (58% vs 0%, p < 0.001), muscle signal (83% vs 48%, p = 0.026), and a soft-tissue mass (67% vs 0%, p < 0.001). On CT, pathologic fractures compared with stress fractures exhibited marrow abnormality (84% vs 17%, respectively; p = 0.001), endosteal scalloping (44% vs 0%, p = 0.006), and aggressive periosteal reaction (36% vs 0%, p = 0.04). CONCLUSION: MRI is useful for distinguishing pathologic from stress fractures, especially after inconclusive radiographic findings. Specifically, pathologic fractures exhibit well-defined T1 marrow alterations, endosteal scalloping, and adjacent soft-tissue abnormalities.

Adolescent↗
PubMed2005

Functional MR cholangiography: diagnosis of functional abnormalities of the gallbladder and biliary tree.

OBJECTIVE: Our objective was to describe the technique and utility of functional MR cholangiography (fMRC) in the evaluation of the gallbladder and biliary tree. CONCLUSION: FMRC has the potential to provide a comprehensive examination for the anatomic and functional assessment of the gallbladder and biliary tree. Complex anatomic abnormalities and functional disorders can be shown by fMRC, including biliary obstruction and extravasation.

Biliary Tract↗
PubMed2003

MR imaging of liver tumors.

The article reviews the current MR imaging techniques commonly utilized for imaging liver tumors. Breath-hold T1-weighted GRE sequences, FSE T2-weighted sequences, and properly timed contrast-enhanced 3D SGE are important for lesion characterization. New liver-specific contrast agents improve lesion detection and are useful in lesion characterization.

Contrast Media↗
PubMed2003

Surgically staged focal liver lesions: accuracy and reproducibility of dual-phase helical CT for detection and characterization.

PURPOSE: To assess the accuracy and reproducibility of dual-phase helical computed tomography (CT) in enabling preoperative detection and characterization of surgically staged focal liver lesions. MATERIALS AND METHODS: Surgically and histopathologically proven liver lesions were evaluated by three experienced CT readers. These lesions were present in 77 patients who underwent dual-phase helical CT. Images were interpreted separately by the three blinded reviewers. Each lesion was graded on a nine-point scale of confidence, with 1 being definitely benign, 9 being definitely malignant, and 5 being indeterminate. The chi2 test was used to determine if the distribution of lesion classifications was different between readers. RESULTS: There was a total of 237 lesions: 73 were benign and 164 were malignant. Sensitivity for lesion detection was 69%, 70%, and 71% for the three reviewers, respectively. Specificity was 91%, 86%, and 90%, and the area under the curve for the alternative-free response receiver operating characteristic curve was 0.84, 0.83, and 0.85, respectively. The difference in the distributions of lesion classification between the three reviewers was not statistically significant (P =.67) as determined by chi2 analysis. CONCLUSION: Dual-phase CT has sensitivity of 69%-71% and high specificity (86%-91%) in enabling the detection and characterization of focal liver lesions. Interpretation is highly reproducible, as there is minimal variation between experienced reviewers.

Female↗
PubMed2003

Living donor liver transplantation in adults: vascular variants important in surgical planning for donors and recipients.

OBJECTIVE: The purpose of our study was to explore the frequency with which surgically important hepatic vascular variants occur independently as well as in genetically related adult candidates for donation or receipt of a liver transplant. MATERIALS AND METHODS: We conducted a retrospective study of 107 adult living donor liver transplant candidates. From this pool of candidates, 50 sets of close relatives were selected to undergo transplantation. As part of the preoperative evaluation, all underwent multidetector CT angiography for evaluation of arterial and venous anatomy. Nonionic IV contrast material (180 mL) was given at a rate of 5 mL/sec, and collimations of 1.25 and 2.50 mm were used for true arterial and portal hepatic venous phase scanning, respectively. Image processing included three-dimensional volume renderings and multiplanar reformations. Two radiologists assessed the prevalence of vascular variants that were important for surgical planning and execution. RESULTS: We identified surgically important hepatic vascular variants in 70 (65%) of the 107 patients. A total of 129 variants were identified, of which 27 were important surgical considerations for recipients, 37 were important for donors, and 65 were important for both recipients (19 variants) and donors (46 variants). Of the 50 pairs of close relatives, 10 (20%) of the pairs were found to have the same hepatic vascular variant or one that was similar. However, when the pairs were set randomly, with no genetically related pairs included, similar variants were noted in 11 pairs (22%). The most common hepatic arterial variant in all candidates was an accessory right or left hepatic artery. The most common hepatic venous variant was an accessory right inferior hepatic vein. CONCLUSION: We observed a high prevalence of surgically important vascular variants in living adult candidates for living liver transplant donation and receipt. Because of the frequent occurrence, similar variants are to be expected among these sets of patients, regardless of whether they are closely related.

Adult↗
PubMed2003

Carcinosarcoma of the urinary bladder: dynamic contrast-enhanced MR imaging with clinical and pathologic correlation.

OBJECTIVE: This article describes the MR imaging features of carcinosarcoma of the urinary bladder with clinical presentation and pathologic correlation in three adults. CONCLUSION: Carcinosarcoma of the urinary bladder is a rare and aggressive tumor that has a clinical presentation similar to that of transitional cell carcinoma of the bladder. Dynamic gadolinium-enhanced MR imaging features are discussed.

Aged↗