Evaluation of canine prostate volume in calculated tomographic images - comparison of two assessment methods.

BACKGROUND: Since most prostatic diseases are associated with the organ's enlargement, evaluation of prostatic size is a main criterion in the diagnosis of prostatic state of health. While enlargement is a non-uniform process, volumetric measurements are believed to be advantageous to any single dimensional parameter for the diagnosis of prostatomegaly. In a previous study, volume was analysed with a slice addition technique (SAT), which was validated as highly accurate. Irrespective of high accuracy, SAT represents a complex and time-consuming procedure, which limits its clinical use. Thus, demand exists for more practical volume assessment methods. In this study, the prostatic volume of 95 canine patients (58 intact males, 37 neutered males) were analysed retrospectively by using the ellipsoid formula (Formula) and an imaging "wrap" function tool (Wrap) to help assess accuracy and applicability. Accuracy was checked against phantom measurements and results were compared to SAT measurements of the same patient pool obtained from a previously published paper. Patients were grouped according to prostatic structure (H = homogeneous, I = inhomogeneous, C = cystic) and volume using the SAT (volume group = vg: 1, 2 and 3). RESULTS: High correlation between the Formula or Wrap volume and the phantom volume was found, the values being higher for the Formula. Mean Formula volumes (vg 1: 2.2 cm3, vg 2: 14.5 cm3, vg 3: 109.4 cm3, respectively) were significantly underestimated, while mean Wrap volumes (vg 1: 3.8 cm3, vg 2: 19.5 cm3, vg 3: 159.2 cm3) were statistically equivalent to SAT measurements (vg 1: 3.1 cm3, vg 2: 18.6 cm3, vg 3: 157.2 cm3, respectively). Differences between Formula and SAT volumes ranged from 22.4-31.1%, while differences between Wrap and SAT volumes were highest in small prostates (vg 1: 22.1%) and fell with increasing prostatic size (vg 3: 1.3%). CONCLUSION: The Wrap function is highly accurate, less time-consuming and complex compared to SAT and could serve as beneficial tool for measuring prostatic volume in clinical routine after further validation in future studies. The Formula method cannot be recommended as an alternative for volumetric measurements of the prostate gland due to its underestimation of volumes compared to SAT results.

Assessment of left ventricular volumes by use of one-, two-, and three-dimensional echocardiography versus magnetic resonance imaging in healthy dogs.

OBJECTIVE: To quantify left ventricle (LV) volumes by use of 1-D, 2-D, and 3-D echocardiography versus MRI in dogs. ANIMALS: 10 healthy Beagles. PROCEDURES: During anesthesia, each dog underwent an echocardiographic examination via the Teichholz method, performed on the basis of standard M-mode frames (1-D); the monoplane Simpson method of disk (via 2-D loops); real-time triplane echocardiography (RTTPE) with a 3-D probe; and real-time 3-D echocardiography with a 3-D probe. Afterward, cardiac MRI was performed. Values for the LV end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) were compared between each echocardiographic method and the reference method (cardiac MRI). RESULTS: No significant differences for EDV, ESV, and EF were detected between RTTPE and cardiac MRI. Excellent correlations (r = 0.97, 0.98, and 0.95 for EDV, ESV, and EF, respectively) were found between RTTPE and values for cardiac MRI. The other echocardiographic methods yielded values significantly different from cardiac MRI and results correlated less well with results of cardiac MRI for EDV, ESV, and EF. Use of the Teichholz method resulted in LV volume overestimation, whereas the Simpson method of disk and real-time 3-D echocardiography significantly underestimated LV volumes. CONCLUSIONS AND CLINICAL RELEVANCE: Use of RTTPE yielded excellent correlations and nonsignificant differences with cardiac MRI and is a suitable method for routine veterinary cardiac examination.

Comparative assessment of left ventricular function variables determined via cardiac computed tomography and cardiac magnetic resonance imaging in dogs.

OBJECTIVE: To evaluate the accuracy and reproducibility of left ventricular (LV) volumetric and function variables determined via contrast-enhanced cardiac CT and cardiac MRI in healthy dogs. ANIMALS: 10 healthy Beagles. PROCEDURES: Cardiac MRI and cardiac CT were performed in anesthetized Beagles; both examinations were conducted within a 2-hour period. Cardiac MRI was performed with a 3.0-T magnet, and contrast-enhanced cardiac CT was performed with a 64-row detector CT machine. Data sets were acquired during apnea with simultaneous ECG gating. Short-axis images were created to determine functional variables via the Simpson method. RESULTS: Cardiac CT values for mean end-diastolic and end-systolic LV volumes had excellent correlation (r = 0.95) with cardiac MRI measurements, whereas LV stroke volume (r = 0.67) and LV ejection fraction (r = 0.75) had good correlations. The only variable that differed significantly between imaging modalities was end-diastolic LV volume. For each pair of values, Bland-Altman analysis revealed good limits of agreement. CONCLUSIONS AND CLINICAL RELEVANCE: The 3-D modalities cardiac CT and cardiac MRI were excellent techniques for use in assessing LV functional variables. Similar results were obtained for LV volume and function variables via both techniques. The major disadvantage of these modalities was the need to anesthetize the dogs for the examinations.

Comparison of multi-detector row computed tomography with echocardiography for assessment of left ventricular function in healthy dogs.

OBJECTIVE: To evaluate the use of retrospectively ECG-gated, contrast-enhanced, multi-detector row computed tomography (MDCT) for assessment of left ventricular function in dogs and to compare the results with those obtained by use of 2-D and M-mode echocardiographc techniques. ANIMALS: 10 healthy Beagles. PROCEDURES: Dogs underwent MDCT (performed by use of a 64-detector row CT system) and echocardiography under general anesthesia. Left ventricular end-systolic volume (ESV), end-diastolic volume (EDV), and ejection fraction (EF) were determined in MDCT-generated multiplanar reformatted images by use of Simpson and biplane area-length calculation methods. Results were compared with left ventricular ESV, EDV, and EF determined in echocardiographc images by use of Teichholz and bullet method calculations. Results were evaluated via Deming regression analysis and Pearson correlation tests. Bland-Altman analysis was used to assess limits of agreement and systematic errors between the 2 methods. RESULTS: Mean values for EDV and ESV determined by use of MDCT were highly correlated with those determined by use of echocardiography, regardless of the calculation methods compared (r = 0.91 to 0.96); volumes determined by use of MDCT appeared to be higher than those determined by use of echocardiography, although most differences were nonsignificant. Mean EF determined by use of MDCT with the Simpson calculation method was highly correlated with that determined by use of echocardiography with bullet method calculations (r = 0.90). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that assessment of left ventricular volume and function in dogs is feasible with MDCT. To estimate left ventricular EF with MDCT. use of the Simpson calculation method is advised.