whewellite and calcium-phosphate--dibasic--dihydrate

Topics: Apatites; Calcium Compounds; Calcium Oxalate; Calcium Phosphates; History, 18th Century; History, 19th Century; History, 20th Century; Humans; Magnesium Compounds; Minerals; Names; Phosphates; Struvite; Urinary Calculi

To assess the potential of automated machine-learning methods for recognizing urinary stones in endoscopy.. Surface and section images of 123 urinary calculi (109 ex vivo and 14 in vivo stones) were acquired using ureteroscopes. The stones were more than 85% 'pure'. Six classes of urolithiasis were represented: Groups I (calcium oxalate monohydrate, whewellite), II (calcium oxalate dihydrate, weddellite), III (uric acid), IV (brushite and struvite stones), and V (cystine). The automated stone recognition methods that were developed for this study followed two types of approach: shallow classification methods and deep-learning-based methods. Their sensitivity, specificity and positive predictive value (PPV) were evaluated by simultaneously using stone surface and section images to classify them into one of the main morphological groups (subgroups were not considered in this study).. Using shallow methods (based on texture and colour criteria), relatively high sensitivity, specificity and PPV for the six classes were attained: 91%, 90% and 89%, respectively, for whewellite; 99%, 98% and 99% for weddellite; 88%, 89% and 88% for uric acid; 91%, 89% and 90% for struvite; 99%, 99% and 99% for cystine; and 94%, 98% and 99% for brushite. Using deep-learning methods, the sensitivity, specificity and PPV for each of the classes were as follows: 99%, 98% and 97% for whewellite; 98%, 98% and 98% for weddellite; 97%, 98% and 98% for uric acid; 97%, 97% and 96% for struvite; 99%, 99% and 99% for cystine; and 94%, 97% and 98% for brushite.. Endoscopic stone recognition is challenging, and few urologists have sufficient expertise to achieve a diagnosis performance comparable to morpho-constitutional analysis. This work is a proof of concept that artificial intelligence could be a solution, with promising results achieved for pure stones. Further studies on a larger panel of stones (pure and mixed) are needed to further develop these methods.

Topics: Artificial Intelligence; Cystine; Humans; Struvite; Uric Acid; Urinary Calculi

Previous studies have shown that split-bolus protocols in virtual non-contrast (VNC) reconstructions of dual-energy computed tomography (DE-CT) significantly decrease radiation dose in patients with urinary stone disease. To evaluate the impact on kidney stone detection rate of stone composition, size, tube voltage, and iodine concentration for VNC reconstructions of DE-CT.. In this prospective study, 16 kidney stones of different sizes (1.2-4.5 mm) and compositions (struvite, cystine, whewellite, brushite) were placed within a kidney phantom. Seventy-two scans with nine different iodine contrast agents/saline solutions with increasing attenuation (0-1400 HU) and different kilovoltage settings (70 kV/150 kV; 80 kV/150 kV; 90 kV/150 kV; 100 kV/150 kV) were performed. Two experienced radiologists independently rated the images for the presence and absence of stones. Multivariate classification tree analysis and descriptive statistics were used to evaluate the diagnostic performance.. Classification tree analysis revealed a higher detection rate of renal calculi > 2 mm in size compared with that of renal calculi < 2 mm (84.7%; 12.7%; p < 0.001). For stones with a diameter > 2 mm, the best results were found at 70 kV/Sn 150 kV and 80 kV/Sn 150 kV in scans with contrast media attenuation of 600 HU or less, with sensitivity of 99.6% and 96.0%, respectively. A higher luminal attenuation (> 600 HU) resulted in a significantly decreased detection rate (91.8%, 0-600 HU; 70.7%, 900-1400 HU; p < 0.001). In our study setup, the detection rates were best for cystine stones.. Scan protocols in DE-CT with lower tube current and lower contrast medium attenuation show excellent results in VNC for stones larger than 2 mm but have limitations for small stones.. • The detection rate of virtual non-contrast reconstructions is highly dependent on the surrounding contrast medium attenuation at the renal pelvis and should be kept as low as possible, as at an attenuation higher than 600 HU the VNC reconstructions are susceptible to masking ureteral stones. • Protocols with lower tube voltages (70 kV/Sn 150 kV and 80 kV/Sn 150 kV) improve the detection rate of kidney stones in VNC reconstructions. • The visibility of renal stones in virtual non-contrast of dual-energy CT is highly associated with the size, and results in a significantly lower detection rate in stones below 2 mm.

Topics: Calcium Oxalate; Calcium Phosphates; Contrast Media; Cystine; Humans; Image Processing, Computer-Assisted; Iodine; Kidney Calculi; Phantoms, Imaging; Prospective Studies; Radiation Dosage; Struvite; Tomography, X-Ray Computed; Urinary Calculi

Urolithiasis is a frequent and in many cases serious disease. Proper analysis of kidney stone composition is crucial for appropriate treatment and prevention of disease recurrence. In this work, scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy was applied for a study of 30 samples covering the most common types of human kidney stones. The results are analyzed and evaluated in terms of applicability of the method for both routine kidney stone analysis as well as collecting of specific data. The method provides complex information about studied samples including morphology of the stones and of the present crystals or their aggregates. It also brings information on elemental composition of the phases. After application of standardization, quantitative microanalysis with detection limits of 400 ppm (Mg, P, S, Cl, K, Ca), 500 ppm (Na) and 1200 ppm (F) was obtained. Compositional mapping with EDS shows the elemental distribution within a sample. This study demonstrated that information on morphology and chemistry acquired by these methods was highly reliable for identification of phases, even when present in small amounts. It provided information on kidney stone structure, relationships between phases, major and minor element content, and variations in chemical composition related to the growth of the stones. SEM represents a powerful tool in urinary stone analysis, since a single facility can produce a wide spectrum of information. It can be suggested as a basic method used for routine urinary stone identification, whilst bringing additional detailed information that cannot be obtained by other methods.

Topics: Apatites; Calcium Oxalate; Calcium Phosphates; Humans; Microscopy, Electron, Scanning; Spectrometry, X-Ray Emission; Urinary Calculi

We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500-400c m(-1)) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH.

Topics: Calcium Oxalate; Calcium Phosphates; Durapatite; Humans; Kidney Calculi; Magnesium Compounds; Phosphates; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Struvite; Uric Acid

Primary hyperparathyroidism (HPT) is a common cause of urolithiasis. Only a few data are available on stone composition and morphology in HPT patients.. We compared the composition and morphology of stones from 264 HPT patients (143 males and 121 females) and 24 567 non-HPT stone formers (16 918 males and 7649 females) including a subgroup of 1356 patients with idiopathic hypercalciuria (IH) (1049 males and 307 females). We excluded uric acid and infection stones containing struvite.. Calcium oxalate (CaOx) was the most prevalent crystalline species among the main components of stones in all groups. However, CaOx stones were significantly less frequent in patients with vs without HPT (51.9% vs 82.2%; P<0.0001). An inversion of CaOx crystalline phases was observed in HPT and IH patients: whewellite was predominant in 16.3% and 30.2% of cases, respectively, vs 57.4% in the non-HPT group (P<0.001), whereas weddellite was predominant in 35.6% of HPT and 49.5% of IH vs 24.8% of non-HPT stones (P<0.0001). Among calcium phosphates, brushite was 7-fold more frequent in HPT than in non-HPT patients (14.0% vs 2.2%; P<0.0001) and almost three times as frequent as in IH patients (4.9%, P<0.0001). Carbapatite was significantly more frequent in male patients with HPT vs non-HPT or IH patients (23.1% vs 8.3% and 9.9%, P<0.0001). Morphological data showed that pure type I calculi were markedly less frequent in HPT patients (1.1% vs 25.3% in non-HPT group, P<0.0001, and 9.1% in IH subgroup, P<0.001). A high occurrence of IVd calculi and of the association of types IVa and II was observed in HPT vs non-HPT and IH patients (14.4%, 2.3% and 6.3%, P<0.0001 and 58.3%, 17.2% and 29.9%, P<0.0001, respectively).. Our data highlight a striking increase in the proportion of calcium-dependent crystalline species, especially brushite in HPT patients, with particular morphological associations in both genders which were more marked than in IH patients.

Topics: Adult; Apatites; Calcium Oxalate; Calcium Phosphates; Female; Humans; Hyperparathyroidism, Primary; Male; Middle Aged; Predictive Value of Tests; Urinary Calculi

The Rietveld method is one of the most innovative and most important applications in x-ray diffraction and has now, for the first time, been applied to standard-free precise quantitative crystallographic analysis of urinary stones.. The capability of the Rietveld method was demonstrated by analysis of a synthetic mixture of five typical urinary stones: whewellite, hydroxylapatite, brushite, struvite, and uric acid, with 20 weight % for each pure component.. The quantitative phase analysis (Rietveld method) yielded a mean absolute error of only 1.6% for the weight fractions of the single urinary stone components. The largest error in weight fraction, 2.3%, occurred with hydroxylapatite, caused by the typical insufficient crystallinity.. Crystallographic analysis of complex urinary stones with the aid of x-ray diffraction, in combination with a Rietveld structure refinement, is the method of first choice for qualitative and quantitative phase analysis. With this tool, significant changes in weight fractions for recurrent urinary stones can be precisely detected, with therapeutic consequences.

Topics: Calcium Oxalate; Calcium Phosphates; Crystallography, X-Ray; Durapatite; Humans; Magnesium Compounds; Phosphates; Predictive Value of Tests; Recurrence; Risk Factors; Struvite; Uric Acid; Urinary Calculi

The internal-standard method and the powder diffractometer have been applied here to the quantitative determination of urinary stone constituents by x-ray diffraction (XRD). Reference intensity ratios determined for six stone substances were used in the reduction of intensity data. Constituent concentrations calculated for 21 stones were compared with values obtained from an element-sensitive technique. We conclude that XRD analysis alone cannot be regarded as a routine technique for the quantitative characterization of uroliths, but that semiquantitative XRD analysis supplemented by accurate quantitative elemental data is more suitable for the precise determination of true stone composition.

Topics: Calcium Oxalate; Calcium Phosphates; Durapatite; Humans; Hydroxyapatites; Magnesium; Magnesium Compounds; Phosphates; Struvite; Uric Acid; Urinary Calculi; X-Ray Diffraction

19 idiopathic recurrent calcium stone formers were examined on a constant diet supplemented with mineral water of high (386 mg/l) and low (10 mg/l) calcium content. The effects of calcium and oxalate loading were studied separately. Ingestion of mineral water with high calcium content lead to an increase of urinary calcium and a decrease of urinary oxalate compared to mineral water with low calcium content. On the calcium-rich mineral water, urinary saturation with Whewellite was lower and it hardly reached the critical level for calcium oxalate crystallization after oxalate loading, which was in contrast to the results on low calcium mineral water. Urinary Brushite saturation was generally low and showed no significant differences between the two mineral waters.

Topics: Adult; Calcium; Calcium Oxalate; Calcium Phosphates; Calcium, Dietary; Crystallization; Female; Fluid Therapy; Humans; Male; Middle Aged; Mineral Waters; Urinary Calculi

Variations of urinary pH and concentrations of calcium, phosphate, oxalate, magnesium and citrate have been produced by 4 different diets given to 19 idiopathic calcium stone formers. The state of saturation towards whewellite and brushite was directly measured in the 76 urine samples by equilibration with the corresponding salts and was compared to chemical constituents by regression analyses. The state of saturation towards calcium oxalate monohydrate was significantly governed only by the urinary oxalate concentration, and a soluble oxalate fraction not contributing to calcium oxalate chelation was demonstrated. The state of saturation towards brushite was exclusively determined by urinary calcium and pH, the latter below 5.5 showing a high influence on brushite solubility.

Topics: Adolescent; Calcium Oxalate; Calcium Phosphates; Child; Child, Preschool; Female; Humans; Hydrogen-Ion Concentration; Male; Urinary Calculi

Brushite and uric acid calculi were studied by means of scanning electron microscopy with the partial dissolution method and transmission electron microscopy. Brushite calculi consist of radially oriented columnar crystals which have sheet-like substructure. The organic matrix is identified chiefly at the outside of the crystals but partly included between the substructure. The concentric matrix bands are often dislocated between the neighbouring crystals. Uric acid calculi also consist of radially oriented columnar crystals, and a fine meshwork of the organic matrix is incorporated within the crystals. The concentric matrix layers of different density are angled according to the crystal lattice. These findings indicate that the organic matrix arose from a mucinous surface coat, at least in the radially striated calculi. The crystals continued to grow in this gel-state milieu, either thrusting the matrix aside or incorporating it within the crystals.

Topics: Calcium Oxalate; Calcium Phosphates; Crystallography; Humans; Microscopy, Electron; Microscopy, Electron, Scanning; Spectrophotometry, Infrared; Uric Acid; Urinary Calculi

Topics: Adult; Aged; Calcium Oxalate; Calcium Phosphates; Female; Humans; Hydroxyapatites; Magnesium; Magnesium Compounds; Male; Middle Aged; Phosphates; Struvite; Urinary Calculi; X-Ray Diffraction

The mineral composition of 103 stones from Iran was determined by a polarisation microscope and infrared spectroscopy. The commonest components were whewellite (81.5%), weddellite (40.7%), apatite (69%) and ammonium acid urate (24.4%). Ectopic cossification in the nuclei was found in three renal calculi (2.9%). Twenty-five stones were from children, where one of the most frequent patterns was formed by both ammonium acid urate and calcium oxalate. This suggests that a high proportion of the children from Iran with urolithiasis have nutritional disorders.

Topics: Adult; Calcium Oxalate; Calcium Phosphates; Child; Female; Humans; Hydroxyapatites; Iran; Kidney Calculi; Magnesium; Magnesium Compounds; Male; Microscopy, Polarization; Minerals; Phosphates; Spectrophotometry, Infrared; Struvite; Uric Acid; Urinary Bladder Calculi