Prediction of splenic volume by a simple CT measurement: a statistical study

Discrepancies in Splenic Size Measurement: A Comparative Analysis of Ultrasound and Computed Tomography

The accurate measurement of splenic size is essential for the diagnosis and management of various gastrointestinal and hematological conditions. While ultrasound (US) and computed tomography (CT) are widely used imaging modalities for assessing splenic size, discrepancies between their measurements have been observed in clinical practice. This study aimed to analyze the measurement differences between US and CT and identify factors influencing these differences. A retrospective analysis of 598 asymptomatic patients who underwent both abdominal US and CT was conducted. Measurements of splenic size obtained from US, axial CT, and coronal CT scans were compared, and various factors such as patient demographics, operator experience, and imaging parameters were evaluated to elucidate their impact on the measurement discrepancies. The results revealed that US consistently underestimated splenic size compared to CT. The magnitude of the discrepancy was influenced by factors such as patient age, body mass index (BMI), depth of the spleen from skin on US and that on CT, visibility of the splenic hilum on US, sonic window quality, and operator experience. This study underscores the importance of considering these factors when interpreting splenic measurements obtained from different imaging modalities in clinical practice.

Magnetic resonance imaging findings in autoimmune hepatitis: how frequent and reproducible are they?

Objective

To determine the frequency and interobserver reproducibility of the magnetic resonance imaging (MRI) features considered diagnostic for autoimmune hepatitis.

Materials and Methods

Two abdominal radiologists, blinded to pathology data, reviewed the MRI examinations of 20 patients with autoimmune hepatitis, looking for liver enhancement, lymphadenopathy, portal hypertension, and chronic liver disease. The pattern of liver fibrosis was categorized as reticular, confluent, or mixed. Interobserver agreement was assessed by calculating intraclass correlation coefficients and kappa statistics.

Results

The most common abnormal finding on MRI was surface nodularity (in 85%), followed by liver fibrosis with a reticular pattern (in 80%)-categorized as mild (in 25.0%), moderate (in 43.8%), or severe (in 31.2%)-; heterogeneous liver enhancement (in 65%); splenomegaly (in 60%); caudate lobe enlargement (in 50%); and lymphadenopathy (in 40%). The interobserver agreement was almost perfect for surface nodularity (0.83), ascites (0.89), and liver volume (0.95), whereas it was just slight and fair for the degree of fibrosis and for heterogeneous liver enhancement (0.12 and 0.25, respectively). It was also slight and fair for expanded gallbladder fossa and enlarged preportal space (0.14 and 0.36, respectively), both of which are indicative of chronic liver disease.

Conclusion

The interobserver agreement was satisfactory for surface nodularity (the most prevalent abnormal MRI finding), ascites, liver volume, and splenomegaly. Conversely, it was only slight or fair for common but less objective criteria.

Metabolic patterns on [18F]FDG PET/CT in patients with unresectable stage III NSCLC undergoing chemoradiotherapy ± durvalumab maintenance treatment

PURPOSE

In patients with unresectable stage III non-small-cell lung cancer (NSCLC), durvalumab maintenance treatment after chemoradiotherapy (CRT) significantly improves survival. So far, however, metabolic changes of tumoral lesions and secondary lymphoid organs under durvalumab are unknown. Hence, we assessed changes on [18F]FDG PET/CT in comparison to patients undergoing CRT alone.

METHODS

Forty-three patients with [18F]FDG PET/CT both before and after standard CRT for unresectable stage III NSCLC were included, in 16/43 patients durvalumab maintenance treatment was initiated (CRT-IO) prior to the second PET/CT. Uptake of tumor sites and secondary lymphoid organs was compared between CRT and CRT-IO. Also, readers were blinded for durvalumab administration and reviewed scans for findings suspicious for immunotherapy-related adverse events (irAE).

RESULTS

Initial uptake characteristics were comparable. However, under durvalumab, diverging metabolic patterns were noted: There was a significantly higher reduction of tumoral uptake intensity in CRT-IO compared to CRT, e.g. median decrease of SUVmax -70.0% vs. -24.8%, p = 0.009. In contrast, the spleen uptake increased in CRT-IO while it dropped in CRT (median + 12.5% vs. -4.4%, p = 0.029). Overall survival was significantly longer in CRT-IO compared to CRT with few events (progression/death) noted in CRT-IO. Findings suggestive of irAE were present on PET/CT more often in CRT-IO (12/16) compared to CRT (8/27 patients), p = 0.005.

CONCLUSION

Durvalumab maintenance treatment after CRT leads to diverging tumoral metabolic changes, but also increases splenic metabolism and leads to a higher proportion of findings suggestive of irAE compared to patients without durvalumab. Due to significantly prolonged survival with durvalumab, survival analysis will be substantiated in correlation to metabolic changes as soon as more clinical events are present.

Methods of Ultrasound Spleen Morphometry

This article presents a review of the methods of determining spleen size in sonography, computed tomography, and magnetic resonance imaging. The review aims to summarize the data on the methods of estimating the linear dimensions of the spleen and splenic volume and describe the physiological variability of spleen size depending on sex, age, and different physiological conditions. We systematized the methods used for measuring the spleen and presented them in the form of a table, analyzed the results of previous studies, and compared the accuracy of different methods of calculating the splenic volume using a variety of diagnostic methods.

Radiographic assessment of splenic size and correlation with splenic measurements estimated by use of computed tomography in healthy cats

OBJECTIVE

To investigate radiographic variables for correlation with splenic size as estimated with CT in cats.

ANIMALS

38 healthy adult cats.

PROCEDURES

The width and height of the splenic head and total length, segmental length, and width of the spleen were measured on radiographic and CT images obtained from 10 cats in prospective, exploratory experiments. Distance between the splenic head and left kidney, anatomic locations of the head and tail of the spleen, and CT-derived splenic volume were also assessed. Correlation and agreement between radiographic and CT measurements and interobserver agreement for measurements with each method were determined. A retrospective evaluation of radiographs obtained without sedation or anesthesia for 28 cats was performed to establish preliminary guidelines for the measurement deemed the most reliable estimator of splenic size.

RESULTS

Radiographic measurements of total and segmental splenic length were significantly correlated with the respective CT measurements and with splenic volume. Agreement between radiographic and CT measurements of segmental length was good; interobserver agreement was excellent for all variables. In retrospective evaluations, median segmental length of the spleen was 57.87 mm (range, 34.72 to 105.44 mm) on radiographs; the caudal border of the splenic head on lateral views was located from the cranial part of L1 to the caudal part of L2, and the caudal border of the splenic tail on ventrodorsal views was located from the caudal part of L2 to the caudal part of L5.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that segmental length of the spleen on radiographs is a reliable estimator of splenic size in healthy cats.

Splenic vein reconstruction is unnecessary in pancreatoduodenectomy combined with resection of the superior mesenteric vein-portal vein confluence according to short-term outcomes

BACKGROUND

Superior mesenteric vein-portal vein confluence resection combined with pancreatoduodenectomy (SMPVrPD) is occasionally required for resection of pancreatic head tumors. It remains unclear whether such situations require splenic vein (SV) reconstruction for decompression of left-sided portal hypertension (LSPH).

METHODS

The data from 93 of 104 patients who underwent pancreatoduodenectomy (PD) for pancreatic head malignancies were reviewed. Surgical outcomes in three groups-standard PD (control group), PD combined with vascular resection and SV preservation (SVp group), and SMPVrPD with SV resection (SVr group)-were compared. The influence of division and preservation of the two natural confluences (left gastric vein-portal vein and/or inferior mesenteric vein-SV confluences) on portal hemodynamics were evaluated using three-dimensional computed tomographic portography.

RESULTS

No mortality occurred. The morbidity rates were not significantly different among the three groups (18/43, 8/21, and 7/29, respectively; p = 0.306). In the SVr group, three patients had gastric remnant venous congestion, and three had esophageal varices without hemorrhagic potential. No patients had splenomegaly, or severe or prolonged thrombocytopenia. These LSPH-associated findings were less frequently observed when the two confluences were preserved.

CONCLUSIONS

SMPVrPD without SV reconstruction can be safely conducted. Additionally, preservation of these two confluences may reduce the risk of LSPH.

Comparison of volume and attenuation of the spleen between postmortem and antemortem computed tomography

OBJECTIVES

The purpose of this study is to compare the postmortem changes in computed tomography (CT) findings between normal spleen, splenic infarct, and splenic tumor infiltration.

METHODS

The institutional review board approved this study, and informed consent was obtained from the next of kin. We studied 63 consecutive subjects who underwent antemortem CT, postmortem CT, and autopsy between February 2012 and December 2013. Postmortem CT was performed within 1678 min after death and was followed by pathological studies. The subjects were divided into three groups based on the pathological findings: normal, splenic infarct, and splenic tumor infiltration. The volume and attenuation of the spleen were compared between antemortem and postmortem CT using paired t tests. Gender, age, time elapsed since death, and the causes of death were examined as potential confounding factors of the postmortem changes in volume and attenuation.

RESULTS

In all groups, the spleen decreased in volume and attenuation increased on postmortem CT compared with antemortem CT. The postmortem changes in spleen volume and attenuation were not significantly associated with sex, age, time elapsed since death, or causes of death.

CONCLUSIONS

Spleen volume decreased and attenuation increased on postmortem CT compared with antemortem CT in subjects with a normal spleen, splenic infarct, or splenic tumor infiltration. These results should caution us against underestimating the significance of splenomegaly on postmortem CT, misinterpreting reduced splenic volume as the presence of hypovolemic or distributive shock in the subject while alive, and confusing postmortem splenic hyperattenuation with diseases characterized by this finding.

Spleen Volume Variation in Patients with Locally Advanced Non-Small Cell Lung Cancer Receiving Platinum-Based Chemo-Radiotherapy

There is renewed interest in the immune regulatory role of the spleen in oncology. To date, very few studies have examined macroscopic variations of splenic volume in the setting of cancer, prior to or during therapy, especially in humans. Changes in splenic volume may be associated with changes in splenic function. The purpose of this study was to investigate variations in spleen volume in NSCLC patients during chemo-radiotherapy. Sixty patients with stage I-IIIB NSCLC underwent radiotherapy (60Gy/30 fractions) for six weeks with concomitant carboplatin/paclitaxel (Ca/P; n = 32) or cisplatin/etoposide (Ci/E; n = 28). A baseline PET/CT scan was performed within 2 weeks prior to treatment and during Weeks 2 and 4 of chemo-radiotherapy. Spleen volume was measured by contouring all CT slices. Significant macroscopic changes in splenic volume occurred early after the commencement of treatment. A significant decrease in spleen volume was observed for 66% of Ca/P and 79% of Ci/E patients between baseline and Week 2. Spleen volume was decreased by 14.2% for Ca/P (p<0.001) and 19.3% for Ci/E (p<0.001) patients. By Week 4, spleen volume was still significantly decreased for Ca/P patients compared to baseline, while for Ci/E patients, spleen volume returned to above baseline levels. This is the first report demonstrating macroscopic changes in the spleen in NSCLC patients undergoing radical chemo-radiotherapy that can be visualized by non-invasive imaging.

A radiologist's guide to treatment response criteria in oncologic imaging: functional, molecular, and disease-specific imaging biomarkers

OBJECTIVE

This article reviews the functional, molecular, and disease-specific imaging biomarkers of treatment response.

CONCLUSION

Substantial progress has been made in the evolution of drugs directed at specific targets of the tumor lifecycle. These novel agents are predominantly cytostatic, and their efficacy may be optimally evaluated by functional, molecular, and disease-specific imaging biomarkers.

Assessing splenomegaly: automated volumetric analysis of the spleen

RATIONALE AND OBJECTIVES

To define systematic volumetric thresholds to identify and grade splenomegaly and retrospectively evaluate the performance of radiologists to assess splenomegaly in computed tomography (CT) image data.

MATERIALS AND METHODS

A clinical tool was developed to segment spleens from 172 contrast-enhanced clinical CT studies. There were 45 normal and 127 splenomegaly cases confirmed by radiological reports. Spleen volumes were compared to manual measurements using overlap/error. Volumetric thresholds for mild/massive splenomegaly were defined at 1/2.5 standard deviations above the average splenic volume of the healthy population. The thresholds were validated against consensus reports. The performance of radiologists in assessing splenomegaly was retrospectively evaluated.

RESULTS

The automated segmentation of spleens was robust with volume overlap/error of 95.2/3.3%. There were no significant differences (P > .2) between manual and automated segmentations for either normal/splenomegaly subgroups. Comparable correlations between interobserver and manual-automated measurements were found (r = 0.99 for all). The average volume of normal spleens was 236.89 ± 77.58 mL. For splenomegaly, average volume was 1004.75 ± 644.27 mL. Volumetric thresholds of 314.47/430.84 mL were used to define mild/massive splenomegaly (±18.86 mL, 95% CI). Radiologists disagreed in 23.25% (n = 40) of the diagnosed cases. The area under the receiver operating characteristic curve of the volumetric criterion for splenomegaly detection was 0.96. Using the volumetric thresholds as the reference standard, the sensitivity of radiologists in detecting all/mild/massive splenomegaly was 95.0/66.6/99.0% at 78.0% specificity, respectively.

CONCLUSION

Thresholds for the identification and grading of splenomegaly from automatic volumetric spleen assessment were introduced. The volumetric thresholds match well with clinical interpretations for splenomegaly and may improve splenomegaly detection compared with splenic cephalocaudal height measurements or visual inspection commonly used in current clinical practice.

Spleen size in idiopathic and heritable pulmonary arterial hypertension

BACKGROUND

It is unknown whether the spleen size correlates with disease severity and outcome in patients with idiopathic and heritable pulmonary arterial hypertension (PAH).

OBJECTIVES

To determine the prevalence of splenomegaly in PAH and assess whether it correlates with severity of disease and outcome.

METHODS

We identified subjects with either heritable or idiopathic PAH who had Doppler echocardiography, right-heart catheterization and computed tomography (CT) of the chest and/or abdomen that included the spleen.

RESULTS

We included 62 subjects with a mean age (±SD) of 49 (±15) years; 82% were women. Spleen dimensions were 10 (±3), 6 (±2) and 9 (±2) cm for the craniocaudal length, thickness and width measurements, respectively. The median [interquartile range (IQR)] spleen volume was 344 (225-533) cm3. Splenomegaly was observed in 52-63% of the patients, depending on the formula used. The spleen volume was not associated with clinical, echocardiographic or hemodynamic variables. Spleen volume was not associated with adjusted mortality. We studied the characteristics of the spleen during autopsy in 9 patients with idiopathic PAH who died of right-heart failure. The mean (IQR) spleen weight was 220 (151-325) g. We observed early congestion in all but 2 patients who had chronic congestion.

CONCLUSIONS

Splenomegaly of predominantly mild degree is common in idiopathic and heritable PAH. However, spleen size was not associated with clinical, echocardiographic, hemodynamic and survival data in these patients.

Splenic volume model constructed from standardized one-dimensional MDCT measurements

OBJECTIVE

The purposes of this study were to construct a model for estimation of splenic volume from standardized one-dimensional diameters of the spleen and to compare that model with the ellipsoid model for estimation of splenic volume.

MATERIALS AND METHODS

In this retrospective study, segmentation software was used for semiautomated quantification of splenic volume by counting CT voxels in 193 consecutively registered patients. For standardization of one-dimensional measurements, the software was used to measure transaxial diameter in the slice with the largest splenic cross-sectional area. By incorporation of splenic volume and the product of width, thickness, and length into the linear regression equation, a model for estimation of splenic volume was constructed, and its performance was externally assessed. Splenic volume also was calculated with the formula for a prolate ellipsoid. The ellipsoid volume and best-fit volumes were compared with segmented splenic volume by use of Bland-Altman plot and Lin concordance correlation. A value of p < 0.05 denoted statistical significance.

RESULTS

Splenic width was the best one-dimensional predictor of splenic volume (r = 0.84, p < 0.05). The linear regression fitted model for estimation of splenic volume (V(R)) in the initial 100 patients was V(R) = (0.36 × W × T × L) + 28, where W is width, T is thickness, and L is length (R(2) = 0.91, p < 0.05) and was externally validated by estimation of splenic volume in the other 93 patients. Compared with that observed with use of the ellipsoid formula, mean bias decreased from 22.57% to 0.93%, and the Lin coefficient increased from 0.81 to 0.96 with application of the best-fit model for calculation of splenic volume.

CONCLUSION

The best-fit model V(R) = (0.36 × W × T × L) + 28 is more optimized than the ellipsoid formula and is associated with less bias for estimation of splenic volume.

Automated segmentation and quantification of liver and spleen from CT images using normalized probabilistic atlases and enhancement estimation

PURPOSE

To investigate the potential of the normalized probabilistic atlases and computer-aided medical image analysis to automatically segment and quantify livers and spleens for extracting imaging biomarkers (volume and height).

METHODS

A clinical tool was developed to segment livers and spleen from 257 abdominal contrast-enhanced CT studies. There were 51 normal livers, 44 normal spleens, 128 splenomegaly, 59 hepatomegaly, and 23 partial hepatectomy cases. 20 more contrast-enhanced CT scans from a public site with manual segmentations of mainly pathological livers were used to test the method. Data were acquired on a variety of scanners from different manufacturers and at varying resolution. Probabilistic atlases of livers and spleens were created using manually segmented data from ten noncontrast CT scans (five male and five female). The organ locations were modeled in the physical space and normalized to the position of an anatomical landmark, the xiphoid. The construction and exploitation of liver and spleen atlases enabled the automated quantifications of liver/spleen volumes and heights (midhepatic liver height and cephalocaudal spleen height) from abdominal CT data. The quantification was improved incrementally by a geodesic active contour, patient specific contrast-enhancement characteristics passed to an adaptive convolution, and correction for shape and location errors.

RESULTS

The livers and spleens were robustly segmented from normal and pathological cases. For the liver, the Dice/Tanimoto volume overlaps were 96.2%/92.7%, the volume/height errors were 2.2%/2.8%, the root-mean-squared error (RMSE) was 2.3 mm, and the average surface distance (ASD) was 1.2 mm. The spleen quantification led to 95.2%/91% Dice/Tanimoto overlaps, 3.3%/ 1.7% volume/height errors, 1.1 mm RMSE, and 0.7 ASD. The correlations (R2) with clinical/manual height measurements were 0.97 and 0.93 for the spleen and liver, respectively (p < 0.0001). No significant difference (p > 0.2) was found comparing interobserver and automatic-manual volume/height errors for liver and spleen.

CONCLUSIONS

The algorithm is robust to segmenting normal and enlarged spleens and livers, and in the presence of tumors and large morphological changes due to partial hepatectomy. Imaging biomarkers of the liver and spleen from automated computer-assisted tools have the potential to assist the diagnosis of abdominal disorders from routine analysis of clinical data and guide clinical management.

Radiofrequency ablation of the spleen in patients with thalassemia intermedia: a pilot study

OBJECTIVE

We investigated the efficacy and safety of radiofrequency ablation on the hematologic parameters in patients with thalassemia intermedia (TI).

MATERIALS AND METHODS

Radiofrequency ablation of the spleen was performed in 15 children with TI under general anesthesia using a cool-tip radiofrequency probe. These patients were regarded as the radiofrequency ablation group. Nine patients with TI who underwent partial splenectomy during the past 3 years and another 14 patients with TI who underwent total splenectomy were also enrolled in this study as the first and second control groups (CG1 and CG2).

RESULTS

In the radiofrequency ablation group, two (13%) patients showed a significant increase in the mean hemoglobin level compared with the year before (1.5 and 1.8 g/dL). In addition, three (20%) other patients became transfusion-free in the year after radiofrequency ablation. In CG1, one (11%) patient showed a significant increase in hemoglobin the year after partial splenectomy, and another two (22%) patients became transfusion-free. In CG2, six (43%) patients revealed a significant increase in hemoglobin in the year after total splenectomy, and another four (29%) revealed a significant decrease in the need for transfusions. The mean increase in hemoglobin and platelet count was more significant in CG2 than in the radiofrequency ablation group and CG1. The mean hospital stay was significantly shorter in the radiofrequency ablation group (1.7 days vs 7.5 and 8.2 days in CG1 and CG2, respectively).

CONCLUSION

We believe that radiofrequency ablation of the spleen can be a safe procedure in patients with TI and is at least as effective as partial splenectomy, having only minor self-limiting complications.

Atlas-based Automated Segmentation of Spleen and Liver using Adaptive Enhancement Estimation

The paper presents the automated segmentation of spleen and liver from contrast-enhanced CT images of normal and hepato/splenomegaly populations. The method used 4 steps: (i) a mean organ model was registered to the patient CT; (ii) the first estimates of the organs were improved by a geodesic active contour; (iii) the contrast enhancements of liver and spleen were estimated to adjust to patient image characteristics, and an adaptive convolution refined the segmentations; (iv) lastly, a normalized probabilistic atlas corrected for shape and location for the precise computation of each organ's volume and height (mid-hepatic liver height and cephalocaudal spleen height). Results from test data demonstrated the method's ability to accurately segment the spleen (RMS error = 1.09mm; DICE/Tanimoto overlaps = 95.2/91) and liver (RMS error = 2.3mm, and DICE/Tanimoto overlaps = 96.2/92.7). The correlations (R(2)) with clinical/manual height measurements were 0.97 and 0.93 for the spleen and liver respectively.

Determination of Splenomegaly by CT: Is There a Place for a Single Measurement?

OBJECTIVE

Our objective was to determine if there is a single parameter that can be used as a marker of splenomegaly using CT.

MATERIALS AND METHODS

Splenic length, width, and thickness were measured in 249 CT scans and multidimensional indexes were obtained from the multiplication of these measurements. Volume was calculated by summing the volumes of multiple contiguous scans. The relationship of the spleen to the left liver lobe and inferior third of the left kidney was also evaluated. Linear equations were obtained to correlate each measurement to the splenic volume.

RESULTS

The unidimensional measurements with best correlation to volume were splenic length (r = 0.81, p < 0.01) and width (r = 0.804, p < 0.01). Correlation was better for the multidimensional indexes (r = 0.95, p < 0.01). Using a previously described upper limit of normality for splenic volume of 314.5 cm3 in the linear regression equation obtained, a maximum spleen length of 9.76 cm was the upper limit of normality. The relation of the lowest point of the spleen to the inferior third of the kidney also showed that if the spleen reached or extended below this portion of the kidney, it could be used as evidence of splenomegaly (p < 0.005), although it had a low sensitivity.

CONCLUSION

Splenic length and multidimensional indexes correlate well with splenic CT volume. A splenic length of 9.76 cm can be used to accurately diagnose splenomegaly and can replace multiple-measurement, time-consuming methods in the clinical routine.

Laparoscopic splenectomy: multi-detector row CT for preoperative evaluation

PURPOSE

To prospectively evaluate multi-detector row spiral computed tomography (CT) for determination of splenic volume, splenic vascular anatomy, and presence of accessory spleens and parenchymal lesions in patients who were undergoing laparoscopic splenectomy.

MATERIALS AND METHODS

Twenty-two patients who were candidates for laparoscopic splenectomy underwent multiphasic multi-detector row CT. Two observers evaluated splenic volume with two hand-tracing editing modalities. Variability between the two observers was calculated with a reliability coefficient (Cronbach alpha). A linear regression equation for each modality was generated to identify the correlation between the two observers. Multi-detector row CT angiography was evaluated for assessment of splenic vascular anatomy. Presence and number of both accessory spleens and parenchymal lesions were recorded.

RESULTS

Mean splenic volume was 1,050 and 1,046 mL, respectively, for observers A and B by using each-section editing (technique 1) and 1,067 and 1,068 mL for observers A and B by using distanced editing (technique 2). For each editing modality, alpha reliability coefficient was higher than 0.99. Both techniques 1 and 2 were very highly predictive of specimen weight and had R2 values of greater than 0.99 (P <.001). CT angiograms correctly showed polar arteries in all cases and the presence of the arteria pancreatica magna in one case. Multi-detector row CT demonstrated the presence, number, and size of all accessory spleens and of focal parenchymal lesions.

CONCLUSION

Multi-detector row CT volumetric and anatomic evaluation provided accurate and reproducible information.

Estimating splenic volume: sonographic measurements correlated with helical CT determination

OBJECTIVE

The purpose of this study was to determine which sonographic measurements of the spleen most closely correlate with splenic volume as determined on helical CT.

MATERIALS AND METHODS

From October 17, 2000, to April 27, 2001, 142 consecutive patients prospectively underwent abdominal helical CT and sonography as part of an evaluation for liver disease. Calculations of splenic volumes were based on 10-mm unenhanced images. Maximum length (ML) and width (W), thickness (T), and craniocaudal length (CCL) were measured sonographically. Standard ellipsoid volume formulas (with the addition of new ellipsoid coefficients) and linear regression formulas were calculated for 117 patients whose examinations were performed within 30 days of each other. Mean percent differences, standard deviations, and 95% confidence intervals (CI) were calculated.

RESULTS

We calculated the average difference between sonography- and CT-measured volume and the 95% CI for each of the four initial sonographic volume estimates with the ellipsoid method using two lengths and linear regression using two lengths and compared them to CT-determined volume. The ellipsoid formulas were then adjusted for bias. Linear regression formulas were derived in which splenic volumes were separately calculated on the basis of each of the two lengths. Mean percent differences and standard deviations for ellipsoid formulas with varying coefficients using the three length measurements were also calculated.

CONCLUSION

Sonographic measurements allow accurate determination of splenic volume. Estimating splenic volume with the formula 0.524 x W x T x (ML + CCL) / 2 provides the greatest overall accuracy.

Reliability of splenic index to assess splenic involvement in pediatric Hodgkin's disease

The purpose of this study was to determine the reliability of the splenic index (SI) in children with Hodgkin's disease (HD). Seventeen patients who underwent staging laparotomy for HD were included in this study. Pretreatment computed tomography scans of these patients were reviewed retrospectively to determine the SI. The specificity, sensitivity, positive and negative predictive values, and accuracy of the SI were calculated. The sensitivity and specificity of the SI were 50% and 66%, respectively. The SI alone accurately identified or ruled out involvement with HD in 10 of 17 patients. Positive and negative predictive values of the SI were 57% and 60%, respectively. Even with the use of the SI, computed tomography alone remains unreliable to determine splenic involvement in children with HD. Additional imaging studies, especially fluorodeoxyglucose positron emission tomography, may improve the clinical staging of HD.

Determination of height, weight, body mass index, and body surface area with a single abdominal CT image

Techniques for estimation of an individual's height, weight, body mass index (BMI), and body surface area (BSA) with a single abdominal computed tomographic (CT) image were developed. Eighty-seven abdominal CT examinations performed in adult humans were analyzed. Anatomic structures were outlined on the CT section that included L1. Multiple linear regression analysis was used to derive sex-specific predictive equations. Correlation for height was good (r > 0.65). Relationship between predicted weight and actual weight was good (r > 0.93). For BMI and BSA, r was greater than 0.893 and greater than 0.895, respectively. In this study, predictive equations for height, weight, BMI, and BSA were generated.

Spleen size: how well do linear ultrasound measurements correlate with three-dimensional CT volume assessments?

Ultrasound measurement of splenic length is standard practice, but it is not known how well this represents the true size of the spleen. Previous studies, using a combination of measurements from in vivo and resected spleens, were subject to error because of changes in splenic size. The aim of this study was to correlate the dimensions of the spleen measured by ultrasound with the splenic volume measured by helical CT. Ultrasound examination was performed on 50 adult patients at the time of their attendance for abdominal CT. Linear dimensions of the spleen were measured with the patient first in the supine and then in the right lateral decubitus (RLD) position. The splenic volume was calculated from a three-dimensional reconstruction of the CT images. There was good correlation, using Spearman's rank correlation, between ultrasound measurements and CT volumes with correlation coefficients exceeding 0.7 for all parameters except one. The linear measurement that correlated most closely with CT volume was the spleen width measured on a longitudinal section with the patient in the RLD position (correlation coefficient (r)=0.89, p<0.001). There was also good correlation between splenic length measured in the RLD position and CT volume (r=0.86, p<0.001). We conclude that a good correlation exists between in vivo ultrasound assessment of splenic size and true splenic volume. The most accurate single measurement is spleen width measured on a longitudinal section with the patient in the RLD position. However, measurement of splenic length, which is the most commonly used in clinical practice, also correlates well with splenic volume, particularly when performed with the patient in the RLD position.

Correlations between colonic wall thickening in patients with virally induced cirrhosis on CT and clinical status

PURPOSE

The purpose of this work was to determine the frequency and CT imaging spectrum of colonic wall thickening and correlate these with the clinical severity of virally induced cirrhosis.

METHOD

Fifty-nine patients were identified with virally induced cirrhosis and no other causes of colonic wall thickening. The abdominal CT scans of these patients were retrospectively reviewed by two radiologists to determine the presence of colonic wall thickening from the ascending colon to the descending colon, to assess the segmental distribution, and to correlate these findings with the clinical status assessed by Child-Pugh classification, presence of ascites, splenic volume index, varices score, and serum albumin levels.

RESULTS

Colonic wall thickening was identified in 18 (31%) patients. The frequency of the affected distribution of colonic wall thickening was as follows: ascending colon in 17 (29%) patients, transverse colon in 11 (19%) patients, and descending colon in 7 patients (12%). The ascending colon was the most common site of colonic wall thickening (p < 0.001). Ten (17%) patients had multisegmental distributions. Colonic wall thickening had a statistically significant association with Child-Pugh grades A, B, and C (p < 0.0001), presence of ascites (p < 0.0004), splenic volume index (p = 0.0026), varices score (p < 0.0001), and serum albumin levels (p = 0.0364). The segmental distribution of wall thickening significantly correlated with Child-Pugh grades A, B, and C (p = 0.0005), presence of ascites (p < 0.001), varices score (p < 0.0001), serum albumin levels (p < 0.0001), and splenic volume index (p = 0.0135).

CONCLUSION

Colonic wall thickening occurs commonly in patients with virally induced cirrhosis. The presence and number of colonic wall thickening were correlated with the grading of the severity of cirrhosis.

Postprandial decrease in splenic volume demonstrated by magnetic resonance imaging and stereology

The aim of this study was to determine if the volume of the spleen changes after food intake. We applied an unbiased and efficient method for splenic volume estimation using magnetic resonance imaging (MRI) in combination with modern design stereology. MR images of the spleen were obtained for 10 healthy volunteers (five men and five women; mean age 28.9 years [range 23-35 years]) without a history of splenomegaly. The initial scans were performed in the morning after overnight fasting. Each volunteer then consumed a standard balanced meal weighing 500 g [2,460 kJ (627 kcal) energy] with 500 ml of still mineral water. Second identical MR scans were performed approximately 1 hr later. Postprandially, splenic volume decreased by an average of 6.6% (P = 0.005), probably due to increased splanchnic blood flow after food intake.

Hypocholesterolemia in hairy cell leukemia: a marker for proliferative activity

Hypocholesterolemia is a well-documented phenomenon associated with a variety of hematological malignancies and nonmalignant disorders associated with splenomegaly. To determine the incidence of hypocholesterolemia in patients with hairy cell leukemia (HCL), we measured the serum cholesterol levels before and after a single cycle of 2-chlorodeoxyadenosine (2-CdA) in 46 patients. The mean pre-treatment serum cholesterol level was 152.8 mg/dl (range, 60 to 293 mg/dl). The mean post-treatment serum cholesterol level was 190.0 mg/dl. This was significantly higher than the pre-treatment values (P <0.0001). Twelve patients who had previously undergone splenectomy showed a similar response to treatment, with a pre-treatment value of 180.0 mg/dl and a post-treatment value of 219.8 mg/dl (P < 0.0001). However, there was a significant difference in the pre-treatment serum cholesterol levels in the nonsplenectomized patients (143.0 mg/dl) compared to the splenectomized patients (180.0 mg/dl) (P < 0.03). The pre-treatment serum cholesterol did not correlate with the pre-treatment splenic index (correlation coefficient = -0.39, P < 0.065). Similarly, there was no correlation between the change in splenic index and the change in serum cholesterol level post-treatment. These findings suggest that hypocholesterolemia in HCL is related to tumor burden and not to splenomegaly alone. Since cholesterol is critical to hairy cell metabolism and structure, treatment strategies interfering with cholesterol synthesis may be productive.

Pleural fluid volume estimation: a chest radiograph prediction rule

RATIONALE AND OBJECTIVES

We devised a prediction rule for estimating pleural effusion volume on the basis of posteroanterior and lateral chest radiographs.

METHODS

A prediction rule was devised for estimating pleural effusion volume on the basis of the presence or absence of a meniscus on chest radiographs. The rule was tested and validated using separate data sets obtained from a retrospective review of patients having both a chest radiograph and computed tomography (CT) scan (the gold standard) within 24 hr of each other. The accuracy of the prediction rule and the degree of interobserver agreement between the two independent readers were determined.

RESULTS

For the test and validation sets, the weighted accuracies of the prediction rule were 86% and 85%, respectively. The respective weighted interobserver agreements were 97% and 88%. Pleural effusions became visible as a meniscus on the lateral chest radiograph at a volume of approximately 50 ml; at a volume of 200 ml, the meniscus could be identified on the posteroanterior radiograph. At a volume of about 500 ml, the meniscus obscured the hemidiaphragm.

CONCLUSION

The volume of a pleural effusion can be estimated from the chest radiograph appearance with a reasonable degree of accuracy.

Mediastinal lymph node enlargement and splenomegaly in primary hypogammaglobulinaemia

The computed tomography (CT) scans of 37 patients with primary hypogammaglobulinaemia were reviewed to determine the frequency of enlarged mediastinal lymph nodes and splenomegaly in this group. None of the 10 X-linked Agammaglobulinaemia (XLA) patients had enlarged nodes and only one had splenomegaly. Eleven of the 27 Common Variable Immunodeficiency (CVID) group had enlarged nodes (41%) and 13 had splenomegaly (48%). There was no significant correlation between the presence of enlarged nodes and splenic enlargement. Twenty-two patients had bronchiectasis but the presence of bronchiectasis did not correlate with the presence of either splenomegaly or lymphadenopathy. Three to 6 years follow-up is available for 36 of the 37 patients and none of this group have developed lymphoma or other malignancy. Enlarged mediastinal nodes and/or splenomegaly are frequently found in patients with CVID and are usually due to a benign, non-neoplastic, process. Mediastinal lymph node enlargement is not a feature of XLA and splenomegaly is unusual in this condition.

Long-term results of alpha interferon as initial therapy and splenectomy as consolidation therapy in patients with hairy cell leukemia. Final report from the Italian Cooperative Group for HCL

PURPOSE

In 1987 the Italian Cooperative Group for the Study of hairy cell leukemia (HCL) started a prospective trial with the following three major aims: 1) to confirm the effectiveness of alpha-IFN as first-line treatment; 2) to assess the usefulness of splenectomy as consolidation treatment in patients achieving a satisfactory partial remission (PR) with alpha-IFN, and 3) to explore whether splenectomy in patients achieving complete remission (CR) with alpha-IFN can reduce the risk of relapse after discontinuation of the drug.

PATIENTS AND METHODS

One-hundred seventy-seven patients with histologically-confirmed HCL were registered in the HCL88-A trial between December 1987 and January 1992. Inclusion criteria included no previous treatment and age less than 66 years. All patients received total doses of 3 MU of alpha-IFN daily for 12 months except for those who achieved early CR and would stop treatment after 6 or 9 months. Patients could be treated with different alpha-IFNs. At the time of the present analysis, 166 patients (93.8%) were fully evaluable.

RESULTS

Treatment of HCL patients with alpha-IFN at the onset of the disease resulted in 28 CR (16.9%), 103 PR (62.0%), and 27 Minor Remissions (MR) (16.3%). Patients treated with different alpha-IFNs achieved similar results: the overall response rate (CR + PR + MR) was 92.7%, 97.2%, and 95.3% for patients treated with r-alpha-2a, r-alpha 2b, and alpha-N1, respectively. The presence of a leukemic phase and a poor performance status were associated with a statistically significant lower response rate. Patients who were randomly assigned and underwent splenectomy after achieving a PR had a better but not significant 4-year progression-free survival than cases randomized for observation (53% vs. 22%, p = 0.116). Overall, 5 patients died after study entry, with an actuarial 5-year survival rate of 96% for the entire group of 166 patients. After a mean follow-up time of 38 months, only one second malignancy has been recorded.

CONCLUSIONS

Initial therapy with alpha-IFN, regardless of the type of alpha-IFN used, induces satisfactory responses in the majority of patients with HCL, but in most instances discontinuation of treatment results in recurrence of disease. In most cases alpha-IFN improves the performance status of patients and favors a satisfactory bone marrow recovery and thus could still play a role in the initial management of the disease. Although splenectomy following alpha-IFN could prolong the progression free survival, its use should be restricted to selected cases.

Computed tomography assessment of splenic size as a predictor of splenic weight and disease involvement in laparotomy staged Hodgkin's disease

PURPOSE

To evaluate how well splenic size predicts the risk of splenic Hodgkin's disease and to assess how accurately splenic dimensions on computerized tomographic scans predict spleen size and involvement by Hodgkin's disease.

METHODS AND MATERIALS

Splenic weights were obtained from laparotomies performed on 897 patients who presented with Hodgkin's disease and were compared with histologic involvement using logistic regression. Splenic dimensions were measured from preoperative computerized tomographic scans in 94 of these patients, and unidimensional splenic measurements [length (L), width (W), thickness (T)] and their products were compared with splenic weight at laparotomy using linear regression.

RESULTS

Hodgkin's disease involved 42% of the spleens at laparotomy and 31% of those assessed by computerized tomography. Splenic weight averaged 198 +/- 5 g (range 40-2000 g). Weight and involvement were greater with "unfavorable" histologies (mixed cellularity, lymphocyte depletion, and unclassified Hodgkin's disease: 229 +/- 12 g; 62.7% involved) than with "favorable" histologies (nodular sclerosing, lymphocyte predominant, and interfollicular Hodgkin's disease: 191 +/- 5 g; 37.8% involved). Splenic weight was the strongest independent risk factor correlated with Hodgkin's disease in univariate and multivariate analyses in all patients and the only identifiable univariate risk factor among those with computerized tomographic scans. For most patients, however, splenic weight poorly predicted involvement: The probability of involvement never fell below 20% and exceeded 80% when splenic weight exceeded 270 g with unfavorable histologies or 685 g in favorable histologies. Spleens of average weight had a probability of involvement of 36% with favorable histologies, 70% with unfavorable histologies. Unidimensional measurements of the spleen on computed tomography correlated poorly with splenic weight, but their product correlated well (Correlation coefficients: L: 0.73; W: 0.65; T: 0.78; [0.344485 x L x W x T]: 0.94).

CONCLUSIONS

Splenic weight is the strongest factor correlating with the risk of splenic involvement by Hodgkin's disease and can be accurately estimated from three-dimensional measurements on computed tomographic scans, but not from unidimensional measurements. However, splenic weight is not a sensitive predictor of involvement of the spleen by Hodgkin's disease. Therefore, treatment approaches to Hodgkin's disease must be based upon intermediate risks of splenic involvement for most clinically staged patients.

Splenic function: physiology and splenic hypofunction

A wide variety of disorders can result in diminished splenic function. The pathophysiology appears to be clearly defined in some instances, such as congenital asplenia and disorders of splenic vascular obstruction or congestion. In others, such as the autoimmune and GI disorders, the mechanism remains poorly defined. Further research is needed. The hyposplenia which occurs in many of these disorders has been associated with an increased risk of life-threatening, overwhelming bacterial sepsis. In other instances, this complication has not been reported. This certainly should not be interpreted to mean that it cannot occur. The risk of septicemia in hyposplenic disorders is rarely above 10 to 15%. In disorders with minimal inhibition of splenic function, the incidence of sepsis would presumably be less than the 1.5% incidence following surgical splenectomy for trauma. Considering these data, a very large number of patients would have to become asplenic before it would be likely that one would develop sepsis. Furthermore, the lack of awareness of the possibility of hyposplenia-related sepsis in many of these disorders may cause such occurrences to go unrecognized. Finally, since the risk of sepsis is probably less in hyposplenic adults as compared to children, studies on adults may underestimate the incidence of this complication in children. Many of the disorders reported to cause hyposplenia in adults have not been noted to do so in children. In instances such as celiac disease, it may take many years for the complication to manifest so that it would be unlikely for a child to manifest hyposplenia during childhood. However, in other instances, not enough children have been studied to be confident that the hyposplenia and its associated risk of sepsis are not complications that occur in children. Hyposplenia-related bacterial septicemia is a catastrophic complication. If a patient develops a disorder that is potentially associated with hyposplenia, the patient should be observed for signs of asplenia in the peripheral blood. If the technique is available, quantitation of red cell pits should be performed. If not, other studies of splenic function such as radionuclide scans should be considered, depending on the incidence of hyposplenia in that particular disorder. If evidence of asplenia develops, pneumococcal vaccine should be administered, penicillin prophylaxis should be considered, significant febrile episodes should be managed aggressively, and probably most importantly, the patient and family should be carefully educated about this complication. Most deaths from hyposplenia-related septicemia are preventable.