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Biomedical subjects

Jonathan B Kruskal

Publications and source records attributed to Jonathan B Kruskal.

At least 19 recordsLinked to original sources
PubMed2006

Right lower quadrant pain: value of the nonvisualized appendix in patients at multidetector CT.

PURPOSE: To retrospectively determine the value of the nonvisualized appendix at multidetector computed tomography (CT) in patients with acute right lower quadrant pain in whom appendicitis was a consideration. MATERIALS AND METHODS: Institutional review board approval was obtained for this HIPAA-compliant study, with waiver of informed consent. Records were retrospectively reviewed in patients who presented to the emergency department between April 29 and October 31, 2003, with right lower quadrant pain. Scanning was performed with the same eight-detector row CT scanner by using oral and (unless contraindicated) intravenous contrast agents, and transverse and coronal reformations were obtained. Two radiologists prospectively evaluated all scans at the time of the examination and rendered a consensus opinion. Clinical follow-up of at least 3 months' duration was performed retrospectively for patients whose appendix was not visualized to determine whether appendicitis had developed. Statistical analysis and calculation of percentages with confidence intervals (CIs) were performed. RESULTS: Of the 400 consecutive patients who underwent multidetector CT, 132 (33.0%) were male and 268 (67.0%) were female. Eighty patients (20.0%) had acute appendicitis and 79 (19.8%) had another cause for abdominal pain. A normal appendix with no other cause for pain was seen in 182 patients (45.5%). In 59 patients (14.8%), the appendix was not visualized. Of these 59 patients, 50 had adequate follow-up. Clinical follow-up was uneventful in 49 of these 50 patients. Thus, on otherwise normal multidetector CT scans in patients suspected of having acute appendicitis, nonvisualization of the appendix was negative for appendicitis in 98% (95% CI: 71%, 100%) of cases. Conversely, when the appendix was seen at multidetector CT and was abnormal, appendicitis was present in 95% (95% CI: 72%, 100%) of cases. CONCLUSION: In patients with right lower quadrant pain, a nonvisualized appendix at multidetector CT reliably excludes acute appendicitis.

Acute Disease↗
PubMed2006

Multiple-image in-room CT imaging guidance for interventional procedures.

This HIPAA-compliant study was approved by the institutional review board; informed consent was not required. The purpose of this study was to retrospectively compare room use time for interventional procedures performed with multiple-image multi-detector row computed tomographic (CT) fluoroscopy (n=196) and single-image spiral CT fluoroscopy (n=175). There was no statistically significant difference in age, sex, or procedural type between the two groups. The median room use time was 90 minutes (interquartile range, 65-120 minutes) for the single-image technique and 75 minutes (interquartile range, 60-105 minutes) for the multiple-image technique. A two-sample t test with equal variance assumption on the log-transformed data showed a statistically significant difference in log time (P<.001) between the two groups. This time savings could potentially have a substantial clinical effect on resource use and patient throughput.

Adult↗
PubMed2006

Intraoperative laparoscopic ultrasound.

In parallel with the increasing move from open surgical procedures to laparoscopic approaches, laparoscopic ultrasound (LUS) is being used with increasing frequency to image normal structures and intra-abdominal pathology. Special transducers and scanning techniques are required to perform LUS with a different set of considerations. Within the spectrum of LUS applications, LUS is used to complement laparoscopy for oncology staging, to facilitate an array of surgical procedures, and to guide laparoscopic biopsies.

Biopsy↗
PubMed2006

Science to practice: Will improved assessment of response to antiangiogenic therapies be achieved with contrast-enhanced gray-scale US?

McCarville et al have used gray-scale contrast-enhanced low-mechanical-index, and thus non-bubble-destructive, continuous US to quantitate tumor blood flow in mouse tumors engineered to simulate antiangiogenic therapy. They have shown that contrast-enhanced gray-scale US, unlike power or color Doppler US performed without contrast enhancement, is better able to depict and distinguish microvascular flow in subcutaneously implanted mouse tumors possessing different vascular phenotypes.

Angiogenesis Inhibitors↗
PubMed2006

Implementation of online radiology quality assurance reporting system for performance improvement: initial evaluation.

PURPOSE: To evaluate an online system developed and implemented for reporting and managing quality assurance (QA) events occurring in a radiology department. MATERIALS AND METHODS: This HIPAA-compliant study had institutional review board approval; informed consent was not required. Using repeated plan-do-study-act cycles, a radiology quality management team applied a 10-step process to implement an online reporting system. The system permits remote submission of cases by staff members. The number of weekly submissions to the system over a 9-month period was evaluated and compared with that for the preceding 6 months by using the Mann-Whitney test. Sources and nature of data, actions initiated, and final outcomes were also analyzed. Recorded data included forum of discussion, dimension of care, action items, monitoring of follow-up and compliance, and notification status. RESULTS: During the first 9 months of implementation, 605 cases were submitted (mean, 21.4 cases per week), a significant increase (P < .005) compared with the preceding 6 months (mean, 3.2 cases per week). Cases, which were submitted by residents (121 cases [20.0%]), fellows (94 cases [15.5%]), faculty members (319 cases [52.7%]), or technologists (54 cases [8.9%]), reported technical (33.1%) or administrative (8.0%) issues. The 329 clinical cases (54.4%) included 60 errors in communication (18.2%), 67 errors in interpretation (20.4%), 78 diagnostic delays (23.7%), 99 missed diagnoses (30.1%), and 54 procedural complications (16.4%); some cases were in more than one category. Twenty-three cases (3.8%) resulted in submission-related QA projects, and 69 cases (11.4%) resulted in individuals or sections of the hospital undergoing additional training. CONCLUSION: A secure online QA reporting system promotes reporting of QA events and serves as a database for identifying and managing trends, initiating performance improvement projects, and providing feedback to staff members who submit cases.

Health Services Research↗
PubMed2006

MDCT angiography of acute chest pain: evaluation of ECG-gated and nongated techniques.

OBJECTIVE: The objective of our study was to compare MDCT angiography protocols used in patients with acute chest pain caused by vascular, nonvascular, and cardiac abnormalities. SUBJECTS AND METHODS: In four groups of 20 patients with chest pain each, four MDCT protocols were used based on monitoring vascular attenuation: pulmonary embolism (150 H at pulmonary artery), aortic dissection (200 H at aortic arch), chest pain (200 H at pulmonary artery), and chest pain with ECG gating (150 H at pulmonary artery). Vascular enhancement was assessed by attenuation measurements taken from locations in the pulmonary artery (n = 3) and thoracic aorta (n = 4). The appearance of the coronary artery in regard to opacification and motion was assessed on a scale of 1 to 5 (best). RESULTS: The mean pulmonary artery and aorta attenuation (372 H and 352 H, respectively) was significantly higher (p < 0.005, Student's t test) and the number of vessel attenuation points measuring less than 200 H (1/140) was significantly smaller (p < 0.001, chi-square test) in the chest pain compared with the dissection (318 H, 310 H; 16/140), gated chest pain (304 H, 286 H; 17/14), and pulmonary embolism (302 H, 220 H; 28/140) groups. The median coronary artery visualization score was 4; the proximal regions received a significantly (p < 0.005, Mann-Whitney test) higher grade compared with the middle and distal regions (medians, 5, 4, and 2, respectively). Artifacts were noted on the gated scans. CONCLUSION: The chest pain protocol can be used to assess both the pulmonary arteries and the thoracic aorta, whereas the ECG-gating protocol appears to be a promising adjunct for a comprehensive single chest pain protocol.

Acute Disease↗
PubMed2005

Imaging of cerebrospinal fluid space and movement in mice using near infrared fluorescence.

We developed an optical method for imaging the cerebrospinal fluid (CSF) space and the movement of CSF in mice using a near infrared fluorescence imaging methodology. Indocyanine green bound to high-density lipoprotein (ICG-HDL) was injected into the lumber subarachnoid space of nude mice. The time course of CSF movement was followed over 48 h. The imaging system was configured for epi-fluorescence measurements at near infrared wavelengths using the illumination light and narrow band excitation filtration with central wavelength of 755 nm. Emission light was filtered with a long pass filter with a cutoff at 798 nm. After the injection of ICG-HDL, a strong fluorescence signal clearly delineated the cisterna magna, bilateral supracerebellar/cerebello-pontine angle cistern, and interhemispheric cistern. Much of the fluorescent tracer was washed out within 24h after the injection. This study has therefore demonstrated that an optical method, employing near infrared fluorescence imaging, can determine the CSF space and the movement of CSF in nude mice.

Animals↗
PubMed2005

Intraoperative sonography for neurosurgery.

OBJECTIVE: The purpose of this study was to review the technical aspects and the clinical applications of intraoperative sonography of the central nervous system (CNS) as well as the characteristic appearances of brain and spine diseases. METHODS: A pictorial review of cases is presented on the basis of the performance and interpretation of intraoperative sonography of the CNS from January 1998 to December 2004 at a single academic institution. RESULTS: This technique is most commonly used for the localization and characterization of intracranial and spinal masses. Indications for intraoperative sonography of the CNS are biopsy guidance, tumor resection, and drainage or removal of inflammatory masses. It provides important additional information to the surgeon at the time of the operation and contributes to intraoperative decision making and surgical planning. This article reviews the advantages and limitations of intraoperative sonography of the CNS and highlights the typical appearance of CNS diseases. CONCLUSIONS: Intraoperative sonography of the CNS is an interactive technique and helps the neurosurgeon in decision making and surgical planning.

Adult↗
PubMed2004

Radiofrequency ablation: Effect of pharmacologic modulation of hepatic and renal blood flow on coagulation diameter in a VX2 tumor model.

PURPOSE: To determine whether pharmacologic agents can be used to modulate blood flow in hepatic and renal tumors sufficiently to alter the extent of radiofrequency (RF)-induced coagulation. MATERIALS AND METHODS: VX2 tumors (8-15 mm) were implanted in the liver (n = 25) or kidney (n = 8) of 33 New Zealand White rabbits. RF was applied to tumors for 6 minutes with use of conventional electrodes (125 mA +/- 35; 90 degrees C +/- 2 degrees C tip temperature). In the hepatic model, blood flow was modulated with use of halothane, epinephrine, or arsenic trioxide (2-6 mg/kg). Laser Doppler flowmetry was used to quantify changes in hepatic blood flow. Correlation of blood flow with induced coagulation diameter was performed. RF ablation was then performed in a renal model with and without arsenic trioxide. RESULTS: For liver tumors, halothane and arsenic trioxide reduced blood flow to 40.3% +/- 17.8% and 29% +/- 15% of normal, respectively, whereas epinephrine increased blood flow to 207.8% +/- 97.9%. Correlation of blood flow to coagulation diameter was demonstrated (R(2) = 0.40). Coagulation measured 7 mm +/- 1 with epinephrine, 10 mm +/- 1 with normal blood flow, 12 mm +/- 3 with halothane, and 13 mm +/- 3 with arsenic trioxide (P <.04 compared with controls). In the renal model, arsenic trioxide decreased blood flow (44% +/- 16%) and increased coagulation diameter (10.9 mm +/- 1) compared with controls (84% +/- 11% and 7.6 mm +/- 1; P <.01, both comparisons). CONCLUSIONS: RF-induced coagulation necrosis in rabbit hepatic and renal tumors is affected by tumor blood flow. Pharmacologic modulation of tumor blood flow may provide a noninvasive way to decrease blood flow during thermally mediated ablation therapy, potentially enabling the creation of larger zones of coagulation necrosis.

Adrenergic Agonists↗
PubMed2004

Radiofrequency ablation: modeling the enhanced temperature response to adjuvant NaCl pretreatment.

PURPOSE: To characterize the effects of volume and concentration of adjuvant NaCl pretreatment on radiofrequency (RF) ablation and to model these results to determine their applicability to in vivo systems. MATERIALS AND METHODS: Standardized 1-L 5% agar phantoms were constructed with central wells of varying volume that were filled with a protein-based polymer gel of varying NaCl concentration (0%-35%). RF ablation to the maximum system current output (2000 mA) was applied to internally cooled 2-cm electrodes placed in the center of the gel wells. Remote thermometry was performed 20 mm from the electrode. Temperatures generated within the phantom were then used to model the response surface by using regression analysis. The generated model was then applied to previously published in vivo data to determine its applicability to a porcine liver tissue model. Statistical analyses included one-way analysis of variance to compare the temperatures reached with different NaCl concentrations and volumes with those reached without NaCl. In addition, modeled functions were evaluated for goodness of fit and the statistical significance of their coefficients. RESULTS: NaCl volume and concentration had significant effects on RF-generated heating of the agar phantoms. The mean maximum temperature, 91.4 degree C +/- 0.8 (SD), was reached with 3.5 mL of 10% NaCl gel. This was significantly higher than the mean temperature reached in phantoms containing 0% NaCl gel, 40.3 degree C +/- 4.9 (P <.001). Heat increases to the maximum temperature correlated strongly with the deposited RF energy, with maximum temperatures limited by the current output of the RF generator. The response surface was defined by a generator energy-dependent region and a generator current-limited region, which were best modeled by a modified gamma-variate function and an exponential function, respectively (r2 = 0.92). This model correlated well with previously published in vivo data (r2 = 0.86). CONCLUSION: Modulation of electrical conductivity has different effects on RF ablation response that are dependent on generator capabilities and the volume and concentration of NaCl pretreatment.

Animals↗
PubMed2004

Radiofrequency ablation: effect of surrounding tissue composition on coagulation necrosis in a canine tumor model.

PURPOSE: To determine the effect of surrounding tissue type on coagulation necrosis from radiofrequency (RF) ablation in a homogeneous animal tumor model. MATERIALS AND METHODS: Thirty canine venereal sarcomas were implanted in three tissue sites (subcutaneous, kidney, and lung) in 13 mildly immunosuppressed dogs. Five of 25 tumors, which were 19 mm +/- 3 (mean +/- SD) in diameter, were allocated to each of five groups: (a) subcutaneous tumors, (b) kidney tumors, (c) lung tumors with blood flow, and (d) subcutaneous and (e) renal tumors without blood flow, which was achieved by sacrificing the animal to eliminate tumor perfusion. A sixth group comprised larger subcutaneous tumors (mean diameter, 46 mm +/- 4) that were also treated. RF ablation was performed with a 1-cm tip and 5 minutes of ablation at 90 degrees C +/- 1. Impedance, temperature, and resultant coagulation diameter were recorded and compared. Data were analyzed statistically, including one-way analysis of variance to determine the effect of tissue conductivity (ie, systemic impedance) on necrosis size and tissue temperatures. Linear regression analysis was used to compare changes in impedance between the control and experimental groups. RESULTS: Increasing linear correlation was observed between tumor coagulation diameter and overall baseline system impedance (R(2) = 0.65). RF ablation of lung tumors resulted in the greatest coagulation diameter (13.0 mm +/- 3.5) compared with that in the other groups (P <.01). The smallest coagulation diameter was observed in kidney tumors in the presence of blood flow (7.3 mm +/- 0.6) compared with that in the other groups (P <.01). Elimination of blood flow in kidney tumors increased coagulation diameter to 10.3 mm +/- 0.6 (P <.01). After RF ablation, coagulation diameter in the subcutaneous tumor groups was the same (mean, 9.8 mm +/- 1.0) (difference not significant), regardless of tumor size or presence of blood flow. CONCLUSION: The characteristics of tissue that surrounds tumor, including vascularity and electric conductivity, affect ablation outcome. Predominance of tissue-specific characteristics will likely result in site-specific differences in RF-induced coagulation necrosis.

Animals↗
PubMed2004

US-guided percutaneous cholecystostomy: features predicting culture-positive bile and clinical outcome.

PURPOSE: To assess sonographic and clinical features that might be used to predict infected bile and/or patient outcome from ultrasonography (US)-guided percutaneous cholecystostomy. MATERIALS AND METHODS: Between February 1997 and August 2002 at one institution, 112 patients underwent US-guided percutaneous cholecystostomy (59 men, 53 women; average age, 69.3 years). All US images were scored on a defined semiquantitative scale according to preset parameters: (a) gallbladder distention, (b) sludge and/or stones, (c) wall appearance, (d) pericholecystic fluid, and (e) common bile duct size and/or choledocholithiasis. Separate and total scores were generated. Retrospective evaluation of (a) the bacteriologic growth of aspirated bile and its color and (b) clinical indices (fever, white blood cell count, bilirubin level, liver function test results) was conducted by reviewing medical records. For each patient, the clinical manifestation was classified into four groups: (a) localized right upper quadrant symptoms, (b) generalized abdominal symptoms, (c) unexplained sepsis, or (d) sepsis with other known infection. Logistic regression models, exact Wilcoxon-Mann-Whitney test, and the Kruskal-Wallis test were used. RESULTS: Forty-seven (44%) of 107 patients had infected bile. A logistic regression model showed that wall appearance, distention, bile color, and pericholecystic fluid were not individually significant predictors for culture-positive bile, leaving sludge and/or stones (P =.003, odds ratio = 1.647), common bile duct status (P =.02, odds ratio = 2.214), and total score (P =.007, odds ratio = 1.267). No US covariates or clinical indices predicted clinical outcome. Clinical manifestation was predictive of clinical outcome (P =.001) and aspirating culture-positive bile (P =.008); specifically, 30 (86%) of 35 patients with right upper quadrant symptoms had their condition improve, compared with one (7%) of 15 asymptomatic patients with other known causes of infection. CONCLUSION: US variables can be used to predict culture-positive bile but not patient outcome. Clinical manifestation is important because patients with right upper quadrant symptoms have the best clinical outcome.

Adult↗
PubMed2004

Hepatic perfusion changes in mice livers with developing colorectal cancer metastases.

PURPOSE: To evaluate whether intrahepatic flow alterations occur during formation of hepatic colorectal cancer metastases and to identify possible causes of these alterations. MATERIALS AND METHODS: Intravital imaging of exteriorized livers was performed in 72 live mice. Three groups of mice were studied: a sham-operated control group (n = 24), a group with nonmetastasizing subcutaneous gliomas (n = 24), and a group with developing hepatic CX-1 colon cancer metastases (n = 24). Microvascular flow parameters, leukocyte-endothelial interactions, and wall shear stress were directly measured in hepatic sinusoids and postsinusoidal venules at 2-day intervals prior to and during the development of metastases. The Kruskal-Wallis test was used initially to test for overall equality of medians in each data group. Single posttest comparisons of independent samples were performed with the Mann-Whitney test, with an overall statistical significance of .05. RESULTS: Prior to the development of visible colorectal cancer metastases, significant (P <.05) reductions occurred in sinusoidal and postsinusoidal flow and wall shear rates, coupled with increased leukocyte rolling and adherence. With tumor growth, flow was further compromised in 92% of tumors larger than 0.5 mm in diameter by extrinsic compression of sinusoids and portal venules and narrowing caused by adherent leukocytes. CONCLUSION: Significant intrahepatic flow alterations occur in mouse livers prior to growth of visible metastases and provide a rational explanation for elevation in the Doppler perfusion index that occurs prior to tumor formation.

Animals↗
PubMed2004

Beneficial effects of CD39/ecto-nucleoside triphosphate diphosphohydrolase-1 in murine intestinal ischemia-reperfusion injury.

CD39 (ecto-nucleoside triphosphate diphosphohydrolase-1; E-NTPDase-1), is highly expressed on quiescent vascular endothelial cells and efficiently hydrolyzes extracellular ATP and ADP to AMP and ultimately adenosine. This action blocks extracellular nucleotide-dependent platelet aggregation and abrogates endothelial cell activation. However, CD39 enzymatic activity is rapidly lost following exposure to oxidant stress. Modulation of extracellular nucleotide levels may therefore play an important role in the pathogenesis of vascular injury. Acute ischemic injury of the bowel is a serious medical condition characterized by high mortality rates with limited therapeutic options. Here we evaluate the effects of cd39-deletion in mutant mice and the use of supplemental NTPDase or adenosine in influencing the outcomes of intestinal ischemia-reperfusion. Wild-type, cd39-null, or hemizygous cd39-deficient mice were subjected to intestinal ischemia. In selected animals, 0.2 U/g apyrase (soluble NTPDase) was administered prior to re-establishment of blood-flow. In parallel experiments adenosine/amrinone was infused over 60 min during reperfusion periods. Survival rates were determined, serum and tissue samples were taken. Intravital videomicroscopy and studies of vascular permeability were used to study platelet-endothelial cell interactions and determine capillary leakage. In wild-type animals, ischemia reperfusion injury resulted in 60% mortality within 48 hours. In mutant mice null or deficient for cd39, ischemia reperfusion-related death occurred in 80% of animals. Apyrase supplementation protected all wild-type animals from death due to intestinal ischemia but did not fully protect cd39-null and cd39-hemizygote mice. Adenosine/amrinone treatment failed to improve survival figures. In wild type mice, platelet adherence to postcapillary venules was significantly decreased and vascular integrity was well preserved following apyrase administration. In cd39-null mice, ischemia-reperfusion induced marked albumin leakage indicative of heightened vascular permaeability when compared to wild-type animals (p=0.04). Treatment with NTPDase or adenosine supplementation abrogated the increased vascular permeability in ischemic jejunal specimens of both wild-type mice and cd39-null. CD39 activity modulates platelet activation and vascular leak during intestinal ischemia reperfusion injury in vivo. The potential of NTPDases to maintain vascular integrity suggests potential pharmacological benefit of these agents in mesenteric ischemic injury.

Adenosine↗
PubMed2004

Utility and safety of ultrasound-guided fine-needle aspiration of salivary gland masses including a cytologist's review.

OBJECTIVE: To evaluate the utility and safety of ultrasound-guided fine-needle aspiration of the salivary glands for diagnosis of focal masses in the salivary glands, including the prevalence of nondiagnostic sampling, the impact of the presence of a cytologist during the procedure, and the usefulness of flow cytometry. METHODS: A retrospective analysis of 43 ultrasound-guided fine-needle aspirations of the salivary glands from 36 lesions in 33 patients was performed. Fine-needle aspirations were obtained under sonographic guidance, and 1 to 6 punctures were made with 20- to 25-gauge needles. Ultrasound-guided fine-needle aspirations obtained in the presence of a cytologist were compared with those performed without a cytologist regarding the adequacy of the specimen and the number of punctures performed. Postprocedural complications and the frequency with which flow cytometry was performed were noted. Cytopathologic diagnosis was correlated with clinical follow-up (n = 33) and surgical pathologic findings (n = 10). RESULTS: Cytologic diagnosis was made in 31 (94%) of 33 patients, confirming a neoplastic process in 18 (50%) of 36 and a non-neoplastic process in 16 (44%) of 36. Although the presence of a cytologist at the bedside resulted in a higher prevalence of diagnostic sampling (P < .05), it did not alter the number of punctures performed (mean, 3 punctures). No complications were encountered except for pain in 2 patients. Flow cytometry was helpful in 8 (22%) of 36 patients. CONCLUSIONS: Ultrasound-guided fine-needle aspiration of the salivary glands is a safe procedure with a low prevalence of nondiagnostic sampling. Approximately 44% of patients can be spared surgical intervention through diagnosis of a non-neoplastic process. The presence of a cytologist increases the likelihood of obtaining a diagnostic sample. Flow cytometry was helpful in 22% of patients.

Adult↗