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Isaac R Francis

Publications and source records attributed to Isaac R Francis.

At least 19 recordsLinked to original sources
PubMed2006

Detection, staging and surveillance in renal cell carcinoma.

This article discusses the computed tomography (CT) and magnetic resonance (MR) scanning techniques used for the detection and staging of renal cell carcinoma and their pitfalls. Comparison between the Robson and recent modifications to the TNM classifications is also addressed. The accuracy of CT and MR in the staging of renal cell carcinoma and the role of positron emission tomography (PET) scanning is outlined and finally the surveillance of patients who have had curative treatment of renal cell carcinoma is briefly addressed.

Carcinoma, Renal Cell↗
PubMed2006

Evaluation of imaging-guided core biopsy of pancreatic masses.

OBJECTIVE: The purpose of this study was to determine the sensitivity and accuracy of imaging-guided core biopsy in the diagnosis of pancreatic masses. CONCLUSION: Imaging-guided core biopsy is sensitive, safe, and accurate in the diagnosis of malignant lesions of the pancreas. Benign biopsy findings cannot be used to exclude the presence of a neoplasm, and repetition of a biopsy should be considered if there is high clinical suspicion of malignancy.

Adenocarcinoma↗
PubMed2006

Lack of tumor seeding of hepatocellular carcinoma after percutaneous needle biopsy using coaxial cutting needle technique.

OBJECTIVE: The objective of our study was to determine the incidence of tumor seeding after biopsy of hepatocellular carcinoma (HCC) using a coaxial cutting needle technique. Seeding along the needle track is a dreaded complication of percutaneous biopsy in patients with HCC, particularly in potential liver transplant recipients. Reported seeding rates range from 0.6% to 5.1% using various biopsy techniques. To our knowledge, the rate of seeding using a coaxial cutting needle technique has not been reported. MATERIALS AND METHODS: Retrospective review identified 128 patients with imaging-guided percutaneous liver biopsies positive for HCC. A coaxial cutting needle technique was uniformly used with a 17-gauge introducer and 18-gauge biopsy needle. Radiology and clinical reports were reviewed, and findings at clinical and imaging follow-up were assessed. RESULTS: During the 6-year study period, 1,012 liver mass biopsies were performed, with 128 positive for HCC (100 men and 28 women; average age, 58.4 years). One hundred one patients had more than 30 days of clinical or imaging follow-up (or both) after biopsy (mean, 410 days; range, 33-1,989 days) and constituted the study population. The remaining 27 were excluded because of inadequate follow-up. No suspected or confirmed tumor seeding on imaging, physical examination, or laparotomy was identified. CONCLUSION: We found no tumor seeding after percutaneous biopsy of HCC using a coaxial cutting needle technique. This rate, 0%, is lower than those reported with other techniques. The use of a needle introducer that remains in position during multiple cutting needle passes protects normal tissue along the track and may reduce seeding. This has particular importance for patients with stage I-II HCC, for whom liver transplantation may be curative.

Biopsy, Needle↗
PubMed2005

The clinical role of CT/PET in oncology: an update.

FDG-PET imaging has significantly altered the workup of the oncologic patient. With the introduction of combined FDG-PET/CT scanners, there has been a dramatic improvement in lesion detection, lesion characterization and accurate lesion localization. As attenuation correction can be attained with the CT images, PET exam times have been dramatically reduced, by as much as 50% in many instances. In this overview we briefly outline the advantages of CT/PET in oncology especially in diagnosis and clinical management of the common tumor types for which it is mainly used.

Colonic Neoplasms↗
PubMed2005

Distinct mechanisms of T cell reconstitution can be identified by estimating thymic volume in adult HIV-1 disease.

BACKGROUND: We have attempted to identify factors associated with T cell reconstitution in response to highly active antiretroviral therapy. METHODS: In a prospective, multicenter cohort study, we compared clinical, immune, and viral responses to an initial antiretroviral regimen in older (>or=45 years old) versus younger (18-30 years old) human immunodeficiency virus type 1-infected subjects. Multivariable linear-regression models identified independent factors associated with changes in T cell counts. RESULTS: Older subjects had smaller increases in naive T cells but greater T cell receptor-excision circle DNA content after 48 weeks, despite similar virologic responses and comparable reductions in immune activation. Changes in T cell counts were associated with plasma interleukin (IL)-7 levels in subjects with low thymic scores, whereas first-phase T cell increases (perhaps mediated by redistribution to the circulation of tissue-associated lymphocytes) were associated with reductions in immune activation in subjects with high thymic scores. Reductions in immune activation were associated with reductions in spontaneous lymphocyte apoptosis. CONCLUSIONS: Distinct processes may underlie T cell restoration, according to estimated thymic volumes. IL-7-mediated peripheral expansion may drive T cell restoration in persons with low thymic volume, whereas therapy-associated reversal of immune reactivation may drive T cell losses and their restoration in persons with larger thymic volume.

Adolescent↗
PubMed2005

Efficacy and safety of MR imaging with liver-specific contrast agent: U.S. multicenter phase III study.

PURPOSE: To assess prospectively the efficacy and safety of postcontrast magnetic resonance (MR) imaging with gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) compared with that of precontrast MR imaging in patients who are known to have or are suspected of having liver lesions and who are scheduled for hepatic surgery. MATERIALS AND METHODS: Investigational review board approval and written informed consent were obtained. HIPAA went into effect after data collection. A total of 172 patients were enrolled. After precontrast MR imaging, 169 patients (94 men, 75 women; mean age, 61 years; age range, 19-84 years) received an intravenous bolus of 25 micromol/kg Gd-EOB-DTPA and underwent dynamic gradient-recalled-echo and delayed MR imaging 20 minutes after injection. Arterial and portal phase computed tomography (CT) were performed within 6 weeks of MR imaging. The standard of reference was surgery with intraoperative ultrasonography (US) and biopsy and/or pathologic evaluation of resected liver segments and/or 3-month follow-up of nonresected segments if intraoperative US was not available. Three blinded reviewers and unblinded site investigators identified liver lesions on segment maps. The Wilcoxon signed rank test was used to compare differences in per-patient sensitivity of precontrast and postcontrast MR images. Adverse events were recorded, and patient monitoring and laboratory assay were performed at time of injection and up to 24 hours after contrast material administration. RESULTS: At MR imaging, 316 lesions were identified in 131 patients. In 77% (P = .012), 72% (P = .15), and 71% (P = .027) of patients for readers 1, 2, and 3, respectively, more lesions were seen at precontrast and postcontrast MR imaging combined than at precontrast MR imaging alone. Sensitivity values for blinded readings were significantly greater at postcontrast MR imaging than at precontrast MR imaging for two of three blinded readers. For all blinded readers, combined precontrast and postcontrast MR images showed no difference in sensitivity compared with helical CT scans. The use of MR imaging, however, yielded fewer patients with at least one false-positive lesion (37%, 31%, and 34% of patients for readers 1, 2, and 3, respectively) than did helical CT (45%, 36%, and 43% of patients for readers 1, 2, and 3, respectively). CONCLUSION: Compared with precontrast MR imaging, postcontrast MR imaging with Gd-EOB-DTPA demonstrated improved sensitivity for lesion detection in the majority of blinded readers, with no substantial adverse events.

Adult↗
PubMed2005

Retroperitoneal sarcomas.

Retroperitoneal sarcomas are rare neoplasms. CT or MR imaging is performed in patients with these tumors to detect local extent and distant metastases of the tumor and for preoperative surgical planning. Most sarcomas cannot be characterized as to cell type with CT or MR, with the exceptions being liposarcomas and intracaval leiomyosarcomas. Similarly histological grading cannot be made definitively with imaging alone, the exception being liposarcoma since well differentiated liposarcomas contain more macroscopic fat than do less differentiated liposarcomas. After surgery, follow up imaging with CT or MR and careful scrutiny of the tumor bed and resection site are essential to detect early recurrences, which can often be managed with re-resection.

Diagnostic Imaging↗
PubMed2005

Non-invasive evaluation of the incidentally detected indeterminate adrenal mass.

Clinically silent adrenal masses are discovered incidentally during diagnostic testing or treatment for clinical conditions that are not related to suspicion of adrenal disease; thus, they are commonly referred to as 'incidentalomas'. The widespread use of high-resolution anatomic imaging techniques such as computed tomography (CT) and magnetic resonance (MR) imaging has led to the increased detection of these masses. In many patients without a known extra-adrenal primary malignancy--and even in patients with a primary neoplasm--most adrenal masses ultimately prove to be benign. However, it remains important that these adrenal masses are accurately characterized to exclude the treatable causes of adrenal disease, and also to accurately stage the oncology patient. The purpose of this chapter is to describe the findings and recent advances in non-invasive imaging methods that are now available for the accurate characterization of incidentally detected adrenal masses (i.e. the differentiation of benign from malignant masses). The imaging techniques and the algorithms that are used in our institution for the evaluation of incidentally detected adrenal mass will be described.

Adrenal Gland Neoplasms↗
PubMed2005

Incidence of acute appendicitis in patients with equivocal CT findings.

OBJECTIVE: The purpose of our study was to determine the incidence of acute appendicitis in patients for whom the CT interpretation is deemed equivocal. MATERIALS AND METHODS: Of 1,344 patients referred for CT with suspected appendicitis between January 1998 and December 2002, 172 patients were identified in whom the radiographic findings were equivocal. Two radiologists reviewed the equivocal CT cases, reassessing appendiceal size and the presence of right lower quadrant stranding, fluid, or an appendicolith. The reviewers' findings were correlated with surgical pathology reports and clinical follow-up. RESULTS: Fifty-three (31%) of 172 patients with indeterminate findings on CT scans were subsequently diagnosed with appendicitis. For reviewers 1 and 2, respectively, appendicitis was present in five (14%) of 36 and six (13%) of 47 patients who had isolated appendiceal diameter less than 9 mm, and in 11 (52%) of 21 and in 10 (50%) of 20 patients who had isolated appendiceal dilatation equal to or greater than 9 mm. If a normal diameter appendix (< 6 mm) was visualized in a patient who had right lower quadrant stranding or fluid, appendicitis was present in only one (17%) of six and in four (27%) of 15 patients for reviewers 1 and 2, respectively. If the appendix could not be identified but there was right lower quadrant stranding or fluid, appendicitis was present in seven (37%) of 19 and in eight (53%) of 15 patients. CONCLUSION: Appendicitis is encountered in about 30% of patients with equivocal findings on CT, and the diagnosis should be considered in most of these patients if they are appropriately symptomatic. However, when the appendix measures less than 9 mm alone, the likelihood of appendicitis is much smaller.

Acute Disease↗
PubMed2004

Long-term changes in circulating CD4 T lymphocytes in virologically suppressed patients after 6 years of highly active antiretroviral therapy.

Highly active antiretroviral therapy (HAART) initiated in advanced HIV disease is associated with CD4 lymphocyte increases (200-300 cells/mm3 after 2-4 years), although longer-term cellular dynamics have not been studied. We observed a significant median CD4 lymphocyte increase of 126 cells/mm3 and 54 naive CD4 lymphocytes from year 3 to 6 of HAART among 20 individuals with pre-HAART CD4 cell counts of 100-300 cells/mm3. This cohort represents the longest prospective immunological follow-up of virologically suppressed patients on HAART.

Antiretroviral Therapy, Highly Active↗
PubMed2004

T2-weighted MR imaging in the assessment of cirrhotic liver.

PURPOSE: To assess if T2-weighted magnetic resonance (MR) imaging provides added diagnostic value in combination with dynamic gadolinium-enhanced MR imaging in the detection and characterization of nodular lesions in cirrhotic liver. MATERIALS AND METHODS: Two readers retrospectively and independently analyzed 54 MR imaging studies in 52 patients with cirrhosis. In session 1, readers reviewed T1-weighted and dynamic gadolinium-enhanced images. In session 2, readers reviewed T1-weighted, dynamic gadolinium-enhanced, and respiratory-triggered T2-weighted fast spin-echo images. Readers identified and characterized all focal lesions by using a scale of 1-4 (1, definitely benign; 4, definitely malignant). Multireader correlated receiver operating characteristic (ROC) analysis was employed to assess radiologist performance in session 2 compared with session 1. The difference in the areas under the ROC curves for the two sessions was tested. In a third session, readers assessed conspicuity of biopsy-proved lesions on T2-weighted MR images by using a scale of 1-3 (1, not seen; 3, well seen) and identified causes of reduced conspicuity. RESULTS: Two additional benign lesions were detected by each reader in session 2. Fifty-five lesions had pathologic verification, including 32 malignant, three high-grade dysplastic, and 20 benign nodules. There was no significant difference in the area under the ROC curves between the two sessions (P =.48). Thirty-two lesions were inconspicuous on T2-weighted MR images because of parenchymal heterogeneity, breathing artifacts (particularly in patients with ascites), and lesion isointensity with liver parenchyma. T2-weighted MR imaging was useful in the evaluation of cysts and lymph nodes. CONCLUSION: T2-weighted MR imaging does not provide added diagnostic value in the detection and characterization of focal lesions in cirrhotic liver.

Adult↗
PubMed2004

MRI for preoperative staging of renal cell carcinoma using the 1997 TNM classification: comparison with surgical and pathologic staging.

OBJECTIVE: The purpose of our study was to determine the accuracy of MRI for preoperative staging of renal cell carcinoma using the 1997 TNM classification. MATERIALS AND METHODS: We conducted a retrospective review of MRI performed in 40 consecutive patients with 42 renal cell carcinomas before radical (n = 35) or partial (n = 4) nephrectomy or exploratory laparotomy (n = 3). The interval between imaging and surgery ranged from 1 to 59 days (mean, 17.9 days). Imaging was performed with T1- and T2-weighted, dynamic gadolinium-enhanced, and time-of-flight sequences. MRI and surgical-pathologic staging was performed using the 1997 TNM staging system. MRI staging was compared with surgical-pathologic staging as the gold standard. Agreement between the two staging methods was assessed using the kappa statistic. RESULTS: Agreement between MRI and surgical-pathologic staging was good for T staging (kappa = 0.72 and 0.78 for reviewers 1 and 2 respectively), poor for N staging (kappa = 0.13, both reviewers), good for M staging (kappa = 0.66, both reviewers), and excellent for the assessment of venous involvement (kappa = 0.93, both reviewers). MRI overestimated the T stage in five patients and the N stage in five and underestimated the T stage in three, the N stage in four, the M stage in one, and the extent of venous thrombosis in two patients. CONCLUSION: MRI is a reliable method for preoperative staging of renal cell carcinoma using the 1997 TNM classification, in particular for assessing venous involvement.

Adolescent↗
PubMed2003

Age-related immune dysfunction in health and in human immunodeficiency virus (HIV) disease: association of age and HIV infection with naive CD8+ cell depletion, reduced expression of CD28 on CD8+ cells, and reduced thymic volumes.

Older age is a strong predictor of accelerated human immunodeficiency virus (HIV) disease progression. We investigated the possible immunologic basis of this interaction by comparing older (>/=45 years) and younger (</=30 years) HIV-infected adults with simultaneously enrolled, aged-matched, healthy volunteers. Cross-sectional comparisons suggested age-associated reductions in naive CD8(+) cells and in the expression of CD28(+) on CD8(+) cells among both HIV-infected subjects and control subjects. Opposite patterns of CD4(+) and CD8(+) cell differences were apparent between these subject groups. HIV infection, but not age, was associated with impairments in delayed-type hypersensitivity responses, lymphoproliferation, and spontaneous apoptosis and with alterations in expression of chemokine receptors CCR5 and CXCR4. Reduced thymic volumes were associated with age and with HIV infection among younger, but not older, subjects. Because of their common association with age and HIV disease, naive CD8(+) cell depletion, diminished CD28 expression on CD8(+) cells, and reduced thymic volumes are possible correlates of the interaction of age with HIV disease.

Adolescent↗
PubMed2003

Making cost-effectiveness analyses clinically relevant: the effect of provider expertise and biliary disease prevalence on the economic comparison of alternative diagnostic strategies.

RATIONALE AND OBJECTIVES: This study was performed to assess the incremental cost-effectiveness of initial magnetic resonance cholangiopancreatography (MRCP) and initial endoscopic ultrasonography (EUS) compared with initial endoscopic retrograde cholangiopancreatography (ERCP) and to evaluate the effect of MRCP provider expertise on the relative cost-effectiveness of the three methods. MATERIALS AND METHODS: Thirty patients with suspected biliary disease and referred for ERCP were prospectively evaluated with EUS, MRCP, or ERCP within 24 hours of referral, according to institutional review board-approved protocol. Performance characteristics were measured for EUS and MRCP, with ERCP as the reference standard. A decision analysis compared the clinical and economic effects of three diagnostic strategies (ERCP, EUS followed by ERCP [EUS-ERCP], and MRCP followed by ERCP [MRCP-ERCP]) using prospective EUS and MRCP test characteristics and Medicare reimbursements. The added costs per additional correct diagnosis and per additional false-positive finding averted and the rates and costs of ERCP-related complications were calculated for EUS-ERCP and MRCP-ERCP. Two additional MRCP readers reviewed MRCP data to evaluate interobserver variability and estimate provider expertise. Additional economic analyses incorporated these estimates. RESULTS: Compared with initial ERCP, EUS-ERCP demonstrated 72% of biliary abnormalities and reduced ERCP-related complications by 60%; the corresponding percentages for MRCP-ERCP were 48% and 40%. Initial EUS and initial MRCP decreased the number of ERCP procedures performed by 69% and 49%, respectively. Each correct diagnosis made with ERCP that would not have been made with initial EUS or initial MRCP cost an additional 4,875 dollars or 2,580 dollars, respectively. Each false-positive diagnosis averted with initial ERCP that would have been made with EUS-ERCP or MRCP-ERCP cost an additional 9,750 dollars or 1,548 dollars, respectively. The decision model was most sensitive to disease prevalence. As provider expertise increased, the additional cost of an additional correct diagnosis increased for ERCP compared with MRCP-ERCP, with disease prevalence accentuating provider effects. CONCLUSION: Initial EUS and initial MRCP are less costly than initial ERCP, but provider expertise, biliary disease prevalence, and procedural costs influence incremental cost-effectiveness.

Biliary Tract Diseases↗
PubMed2003

Hepatic arterial phase MR imaging with automated bolus-detection three-dimensional fast gradient-recalled-echo sequence: comparison with test-bolus method.

Sixty-two patients underwent magnetic resonance (MR) imaging of the liver with the automated contrast material bolus-detection technique. Arterial phase MR images were assessed quantitatively and qualitatively. In 23 patients, a test bolus of contrast material was injected intravenously before dynamic MR imaging. There was good correlation and agreement between delay times estimated with both timing methods. Eighty-three percent of arterial phase images obtained with automated contrast material bolus detection were optimal. There was good correlation and agreement between delay times estimated with both timing methods. Optimal hepatic arterial phase MR images can be obtained routinely with automated detection of a contrast material bolus.

Adult↗
PubMed2003

Evaluation of neck and body metastases to nodes with ferumoxtran 10-enhanced MR imaging: phase III safety and efficacy study.

PURPOSE: To determine the safety and efficacy of ferumoxtran 10-enhanced magnetic resonance (MR) imaging for diagnosis of metastases to lymph nodes and the clinical usefulness of ferumoxtran 10 in nodal staging. MATERIALS AND METHODS: One hundred fifty-two patients were injected with ferumoxtran 10. Readers independently evaluated precontrast MR images by using node size criteria and subjective assessment of other imaging features. Ferumoxtran 10-enhanced MR images were evaluated alone and paired with precontrast images for comparison. The diagnostic performances of precontrast MR size criteria and postcontrast MR imaging were evaluated with receiver operating characteristic (ROC) analysis. Lymph node signal intensity was correlated with histopathologic findings. MR imaging and histopathologic nodal stages were compared. RESULTS: Node-level sensitivity, specificity, and accuracy of precontrast MR imaging were 54%, 82%, and 68%, respectively, with node size criterion alone; 91%, 51%, and 71%, respectively, with subjective reader assessment; 85%, 85%, and 85%, respectively, with postcontrast MR imaging alone; and 83%, 77%, and 80%, respectively, with paired pre- and postcontrast MR imaging. Compared with size criteria, subjective reader assessment had higher sensitivity but substantially lower specificity. Areas under the ROC curve for pre- and postcontrast MR imaging were 0.76 and 0.83, respectively. Nonmetastatic nodes had significantly lower signal intensity than metastatic nodes on postcontrast T2-weighted MR images (P <.001). Postcontrast nodal staging was significantly more accurate than precontrast nodal staging (P <.01). Headache, back pain, vasodilatation, and urticaria each occurred in 6% of patients. CONCLUSION: Ferumoxtran 10-enhanced MR imaging was safe and effective and facilitated improved diagnostic performance. Use of iron oxide-enhanced MR imaging increased the positive predictive value by 20% and the accuracy by 14% compared with reader assessment. Differentiating patients with no nodal metastatic involvement was more reliable with ferumoxtran 10-enhanced MR imaging than with precontrast MR imaging.

Adolescent↗
PubMed2003

Effectiveness of MR imaging in characterizing small hepatic lesions: routine versus expert interpretation.

OBJECTIVE: The aim of our study was to compare the effectiveness of MR imaging characterization of small (<or=2 cm) hepatic lesions made in a routine clinical setting with the effectiveness of such characterization made under standardized conditions by radiologists who are expert interpreters of MR imaging. MATERIALS AND METHODS: Forty-eight patients with 69 small (<or=2 cm) hepatic lesions considered indeterminate on a prior routine CT scan were included in the study. The diagnosis for all lesions had been verified by histology (n = 10), surgery and intraoperative sonography (n = 5), imaging follow-up (n = 35), or clinical follow-up (n = 19). Using the initial radiology reports, the diagnoses based on MR imaging were rated on a 5-point confidence scale. In addition, two radiologists experienced in MR imaging who were unaware of the initial interpretations of the images or the clinical histories of the patients independently analyzed the MR imaging studies and characterized the lesions using the same 5-point scale. The observer performance for the initial MR imaging interpretations and the expert interpretations were measured using receiver operating characteristic analysis. Interobserver agreement was determined with weighted kappa statistics. RESULTS: Fifty-eight lesions were benign (six cysts, 22 hemangiomas, four regenerating nodules, two steatohepatitic lesions, one atypical blood vessel, three focal fat and five focal fat-sparing lesions, 13 flow-related pseudolesions, one diaphragmatic insertion, and one unspecified lesion), and 11 lesions were malignant (nine metastases and two hepatocellular carcinoma). The areas under the curve were 0.94 (initial reports), 0.88 (observer 1), and 0.84 (observer 2). Substantial agreement was found between the expert interpreters (kappa = 0.74), and moderate agreement, between the expert interpreters and initial interpreters (kappa = 0.44 each). CONCLUSION: MR imaging is an effective method of characterizing small (<or=2 cm) hepatic lesions in routine clinical practice.

Adult↗