Nidhi Sharma

Parenchymal Volume Preservation and Ischemia During Partial Nephrectomy: Functional and Volumetric Analysis

OBJECTIVE To determine the relative effect of type and duration of ischemia and parenchymal volume preservation on renal function after partial nephrectomy (PN). MATERIALS AND METHODS Ninety-two patients with localized renal tumors (2007-2012) managed with PN at our center with necessary studies for analysis were included. This comprised 37 patients with a solitary kidney and 55 with a contralateral kidney. Thirty-five patients were managed with hypothermia and 57 with limited warm ischemia. Volumetric computed tomography was used to measure the volume of functional parenchyma before and after PN in the operated and contralateral kidneys. Glomerular filtration rate (GFR) was determined by the modification of diet in renal disease 2 equation, along with renal scan data for patients with a contralateral kidney. Regression analysis assessed the relationships between %GFR preserved in the operated kidney and potential predictive factors. All postoperative analyses were performed 4-12 months after surgery. RESULTS Median age was 61 years, median tumor size 3.5 cm, and median RENAL nephrometry score 8. Median cold ischemia time was 28 minutes and median warm ischemia time 21 minutes. Median %GFR preserved in the operated kidney was 79%. Median %parenchymal volume saved was 83%. Function in the contralateral kidney only increased marginally (median increase 6%). On regression analysis, %GFR preserved associated most strongly with %parenchymal volume saved (P <.0001), but also with lower RENAL scores (P = .0457) and the use of hypothermia (P = .0209). In contrast, ischemia time did not correlate with %GFR preserved (P = .5051). CONCLUSION Ultimate function after PN primarily correlated with parenchymal volume preservation, whereas ischemia played a secondary role. Thus, maximal parenchymal preservation with a precise PN should be a priority during PN.

Wegener's Granulomatosis in the Chest: High-Resolution CT Findings

OBJECTIVE Wegeners granulomatosis is an uncommon necrotizing vasculitis having variable presentations in the chest that are best depicted on high-resolution CT. Imaging findings may include nodules, which may cavitate; ground-glass opacity secondary to pulmonary hemorrhage; and airway stenoses and ulcerations. Active Wegeners granulomatosis can mimic pneumonia, septic emboli, and metastases. CONCLUSION This article will illustrate the high-resolution CT findings of Wegeners granulomatosis in the chest.

Correlation Between Loss of Renal Function and Loss of Renal Volume After Partial Nephrectomy for Tumor in a Solitary Kidney

PURPOSE We assessed the correlation between reduced renal function and parenchymal volume following partial nephrectomy. MATERIALS AND METHODS In 21 of 42 patients with tumors in a solitary kidney who were enrolled in a study measuring function before and after surgery underwent computerized tomography, and measurement of the glomerular filtration rate and estimated glomerular filtration rate (the latter at baseline and 2 to 6 months) before and after surgery. A segmentation algorithm was used to measure renal parenchymal volume. The percent of renal parenchymal volume loss was correlated with the percent loss in glomerular filtration rate using the Pearson correlation coefficient. RESULTS Mean +/- SD net preoperative volume was 284 +/- 67 cc (range 179 to 413) and mean net postoperative volume was 240 +/- 61 cc (range 119 to 346) with an absolute functional volume loss of between 5 and 160 cc. The average percent of parenchymal volume loss was 15% (range -2% to 47%). The mean loss of the measured glomerular filtration rate 3 days postoperatively was 33.9% (range -70.7% to 74.4%) and the estimated glomerular filtration rate 2 to 6 months postoperatively was 19.7 % (-6.0% to 45.5%). There was a low degree of correlation between the percent volume loss and the percent measured glomerular filtration rate loss at 3 days (r = 0.28, p = 0.22). However, there was a moderate degree of correlation between the percent volume loss and the percent estimated glomerular filtration rate loss at 2 to 6 months (r = 0.48, p = 0.03). CONCLUSIONS In patients with partial nephrectomy the renal parenchymal volume loss correlates best with the renal function loss several months after surgery. Estimates of volume loss may be useful for predicting postoperative renal function when planning partial nephrectomy in patients with a solitary kidney.

Estimating glomerular filtration rate in kidney donors: a model constructed with renal volume measurements from donor CT scans.

PURPOSE To create a model to estimate glomerular filtration rate (GFR) in healthy individuals, such as renal transplant donors, by using renal volume measurements derived from multidetector computed tomographic (CT) scans, serum creatinine level, height, weight, race, and age, and to compare the performance of this kidney volume-based model with the modification of diet in renal disease (MDRD) equation. MATERIALS AND METHODS This HIPAA-compliant retrospective study was approved by the institutional review board; informed consent was waived. Age, sex, height, weight, race, serum creatinine level, and measured GFR were recorded from 244 individuals who underwent renal donor evaluation over a 2-year period. An automated segmentation algorithm was used to measure renal parenchymal volume from CT images. GFR was measured by using urinary clearance of iodine 125 ((125)I) iothalamate. Analysis of covariance was used to model GFR measured by using (125)I-iothalamate clearance from the significant variables. The model was tested in 100 different renal donors and performance was compared with performance of the MDRD equation. RESULTS Renal volume, age, serum creatinine level, and weight (P < .001) significantly correlated with GFR measured by using (125)I-iothalamate clearance. Sex (P = .6), race (P = .9), and height (P = .76) were not significant. The fitted regression model was GFR(EUn) = 70.77 - 0.444 A + 0.366 W + 0.200 V(R) - 37.317 Cr (r(2) = 0.57), where GFR(EUn) is estimated unadjusted GFR in milliliters per minute, A is age in years, W is weight in kilograms, V(R) is mean total renal volume in milliliters, and Cr is serum creatinine value in milligrams per deciliter (micromoles per liter). Correlation between renal volume-based GFR and GFR measured by using (125)I-iothalamate clearance was +0.42. The model outperformed the MDRD equation in six of six measurements. CONCLUSION A model for estimating GFR that incorporates renal volume correlated well with measured GFR and outperformed the MDRD equation in potential living renal donors; this model could be used to estimate donor GFR from CT scans instead of measuring it by using (125)I-iothalamate clearance.

Predictors of precision of excision and reconstruction in partial nephrectomy.

PURPOSE The precision of excision and reconstruction to optimize vascularized parenchymal preservation is a major determinant of renal function after partial nephrectomy. We assessed partial nephrectomy surgical precision using volumetric computerized tomography and analyzed predictive factors. MATERIALS AND METHODS We analyzed the records of 122 patients treated with partial nephrectomy in whom detailed analysis of the precision of excision and reconstruction specific to the operated kidney could be performed. We used volumetric computerized tomography to measure functional parenchymal volume before and after partial nephrectomy in the operated kidney. The glomerular filtration rate in the operated kidney was determined by the MDRD2 (Modification of Diet in Renal Disease 2) equation along with renal scan in patients with a contralateral kidney. Surgical precision was defined as actual postoperative parenchymal volume/predicted postoperative parenchymal volume, presuming loss of a 5 mm rim of normal parenchyma related to excision and reconstruction. RESULTS Median patient age was 61 years and 64 patients (52%) underwent an open procedure. Cold ischemia was used in 50 patients (median 26 minutes) and limited warm ischemia (median 20 minutes) was used in 72. The R.E.N.A.L. (radius, exophytic/endophytic, nearness of tumor to collecting system or sinus, anterior/posterior and location relative to polar line) nephrometry score indicated low, intermediate and high complexity in 43 (35%), 55 (45%) and 24 patients (20%), respectively. A total of 45 patients (37%) with a solitary kidney were included in analysis. The median precision of excision and reconstruction was 93%. The median preserved glomerular filtration rate was 80% in the operated kidney. A solitary kidney was the only significant predictor of excision and reconstruction precision on univariable and multivariable analysis. CONCLUSIONS A solitary kidney significantly impacted partial nephrectomy surgical precision. This was likely related to the recognized need to preserve as much renal parenchyma as possible to optimize renal function in the absence of a contralateral kidney.

Vanishing Lung Syndrome (Giant Bullous Emphysema): CT Findings in 7 Patients and a Literature Review

Purpose we reviewed the imaging findings in 7 patients with idiopathic giant bullous emphysema. This is a chronic, progressive condition usually affecting young male smokers and is characterized by giant emphysematous bullae, which commonly develop in the upper lobes. Extensive paraseptal emphysema coalesces to form giant bullae, compressing the normal lung parenchyma and often displacing it centrally. These bullae occupy at least one-third of a hemithorax. Materials and Methods Seven patients with chest radiographic evidence of a bulla or bullae occupying at least one-third of a hemithorax, who had also been examined with high-resolution computed tomography (HRCT), were included in this retrospective study. On HRCT scans, the size, location, and distribution of the bullae were documented and categorized as either subpleural or central. Results The HRCT scan findings in all 7 study patients included numerous bullae ranging in size from a few centimeters in diameter to giant bullae nearly filling an entire hemithorax, mimicking a pneumothorax. Five of the 7 patients had extensive upper lobe predominant bullae, 4 of the 7 patients showed severe bilateral disease with asymmetric involvement, 2 of the 7 patients demonstrated left lung predominance and whereas 1 patient showed right lung predominant disease. All of our patients had subpleural bullae, had parenchymal fibrosis, another had extensive subcutaneous emphysema, and 1 had accompanying bronchiectasis. Conclusions The predominant findings on HRCT scans are extensive paraseptal emphysema coalescing into giant bullae. HRCT is helpful in confirming the diagnosis of VLS, assessing the degree of the disease, and providing information to guide treatment.

The impact of functional imaging on radiation medicine

Radiation medicine has previously utilized planning methods based primarily on anatomic and volumetric imaging technologies such as CT (Computerized Tomography), ultrasound, and MRI (Magnetic Resonance Imaging). In recent years, it has become apparent that a new dimension of non-invasive imaging studies may hold great promise for expanding the utility and effectiveness of the treatment planning process. Functional imaging such as PET (Positron Emission Tomography) studies and other nuclear medicine based assays are beginning to occupy a larger place in the oncology imaging world. Unlike the previously mentioned anatomic imaging methodologies, functional imaging allows differentiation between metabolically dead and dying cells and those which are actively metabolizing. The ability of functional imaging to reproducibly select viable and active cell populations in a non-invasive manner is now undergoing validation for many types of tumor cells. Many histologic subtypes appear amenable to this approach, with impressive sensitivity and selectivity reported.For clinical radiation medicine, the ability to differentiate between different levels and types of metabolic activity allows the possibility of risk based focal treatments in which the radiation doses and fields are more tightly connected to the perceived risk of recurrence or progression at each location.This review will summarize many of the basic principles involved in the field of functional PET imaging for radiation oncology planning and describe some of the major relevant published data behind this expanding trend.

Inflammatory myofibroblastic tumor of the lung: recurrence after steroid treatment.

We report a case of a patient with inflammatory myofibroblastic tumor of the lung, which recurred after steroid treatment. The diagnosis of the tumor was confirmed by a core needle lung biopsy and pathology. The patient was initiated on steroid therapy, which on complete response was slowly tapered and discontinued. Few months later, the patient presented with dyspnea again. Chest radiography and computed tomography scans depicted recurrence at the tumor resection site in the right lobe of lung and a new tumor in the left lower lobe. Restarting the steroid therapy, led to regression of the tumors at both sites. This is a rare case of inflammatory myofibroblastic tumor recurring poststeroid therapy and adds to the current clinical knowledge about this peculiar manifestation of this disease entity.

Comparison of 2 Computed Tomography–based Methods to Estimate Preoperative and Postoperative Renal Parenchymal Volume and Correlation With Functional Changes After Partial Nephrectomy

OBJECTIVE To compare freehand scripting and semiautomated renal parenchymal volume measurements on preoperative or postoperative computed tomography scans and assess relationships between parenchymal volume loss and functional changes within the operated kidney after partial nephrectomy (PN). MATERIALS AND METHODS Fifty patients (16 solitary kidneys, 34 bilateral kidneys) with renal tumors managed by PN with necessary studies for analysis were included. Freehand scripting and semiautomated threshold-based analysis were performed before and 4-12 months after PN to obtain preoperative normal parenchymal volumes, projected residual parenchymal volumes, and actual postoperative volumes. Glomerular filtration rate was determined by the Modification of Diet in Renal Disease 2 equation along with nuclear renal scan to provide split function for patients with 2 kidneys. Limits of agreement and Bland-Altman analyses were performed. The relationship between the amount of vascularized parenchyma preserved and renal function saved was correlated for each measurement method using Pearson correlation. RESULTS The semiautomated method yielded estimates that were higher than freehand scripting by a mean of 14 cm(3) for estimation of preoperative normal parenchymal volume, 21 cm(3) for projected residual parenchymal volume, and 9 cm(3) for actual postoperative parenchymal volume. For the semiautomated method, correlation between the amount of normal parenchyma preserved and renal function saved was 0.52 (95% confidence interval [CI], 0.28-0.69; P <.001), and for the scripting method, correlation was 0.60 (95% CI, 0.39-0.76; P <.001). CONCLUSION Semiautomated and freehand scripting measurements of parenchymal volumes were relatively consistent before and after PN, although the semiautomated approach tended to yield volumes that were approximately 5%-10% higher on average. Measurement of parenchymal volume changes by both approaches correlated significantly with functional changes after PN.

Assessment of Outcomes in Partial Nephrectomy Incorporating Detailed Functional Analysis

OBJECTIVE To assess perioperative morbidity and margins after conventional clamped partial nephrectomy (PN) while also using volumetric analysis to differentiate the contributions of parenchymal volume loss and recovery from ischemia. MATERIALS AND METHODS The study analyzed 163 patients who underwent PN with appropriate studies to allow analysis of function and parenchymal mass specifically in the operated kidney. Recovery from ischemia (glomerular filtration rate saved/volume saved) would be 100% if all nephrons recovered from ischemia. Precision (postoperative parenchymal volume/predicted parenchymal volume, presuming loss of a 5-mm rim of parenchyma related to excision and reconstruction) reflects efforts to optimize the amount of vascularized parenchyma saved with the PN. Trifecta was defined as negative margins, no Clavien grade 3-5 or urologic complications, and both recovery ≥80% and precision ≥80%. RESULTS An open procedure was performed in 82 patients (50%), and 59 (36%) had a solitary kidney. Warm ischemia was used in 96 patients (59%). The RENAL nephrometry score (radius, exophytic/endophytic properties of the tumor, nearness of tumor deepest portion to the collecting system or sinus, anterior/posterior descriptor, and the location relative to polar lines) was intermediate in 74 (45%) and high complexity in 38 (23%). Median recovery from ischemia was 95% and was ≥80% in 143 patients (88%). Median precision of excision/reconstruction was 93% and was ≥80% in 138 patients (85%). All tumors had negative surgical margins. Perioperative complications occurred in 13 patients (9%). Trifecta was achieved in 113 patients (69%). Multivariable analysis identified solitary kidney as the only significant predictor of trifecta. CONCLUSION Given careful patient selection and commensurate surgical expertise, excellent outcomes can be obtained with conventional clamped PN. Analysis of parenchymal volumes is necessary to facilitate comprehensive evaluation of functional outcomes after PN, allowing differentiation of nephron loss vs failure to recover from ischemia.