Renal single photon emission computed tomography: should we do it?

Associations of microcirculation damage on nailfold capillaroscopy with supra-aortic severe ischemic events in patients with Takayasu arteritis

OBJECTIVE

To evaluate the clinical characteristics and nailfold microcirculation and explore the associations with severe ischemic events (SIEs) in Takayasu arteritis (TA) with supra-aortic involvement.

METHODS

Eighty-one patients with supra-aortic artery involvement who underwent nailfold video-capillaroscopy (NVC) of their hands were enrolled from the East China TA (ECTA) cohort between August and December 2021. Clinical features and capillaroscopy variables associated with supra-aortic SIEs were analyzed by multivariate logistic regression.

RESULTS

Overall, 71 patients were female, and 42 experienced supra-aortic SIEs, among whom there was a higher prevalence of hypertension and the number of supra-aortic artery stenosis (P = 0.005, and 0.003, respectively). Furthermore, intergroup differences in capillary density (P < 0.001) and minor morphology abnormalities (P < 0.001) were significant. After adjustment for all confounders, multivariate logistic regression revealed hypertension (odds ratio [OR]: 7.3, 95% confidence interval [CI]: 1.6-33.7, P = 0.011), the number of supra-aortic arteries stenosis (≥4, OR: 6.8, 95% CI: 1.4-34.6, P = 0.020), capillary density (≤7.2/mm, OR: 43.0, 95% CI: 7.0-264.6, P < 0.001) and minor abnormalities (OR: 34.2, 95% CI: 3.6-325.1; P = 0.002) were independent risk factors for supra-aortic SIEs. capillary density (≤7.2/mm) and minor abnormalities or combined with at least two of the three items in the matrix model showed the probability of supra-aortic SIEs was 61.2-87.6%.

CONCLUSION

Decreased capillary density and morphologic abnormalities indicated that hypoperfusion was more likely to be observed in supra-aortic SIEs patients. Combined NVC indicators could be instrumental for early identification of supra-aortic SIEs. Key Points • Minor morphological abnormalities and hemorrhages were only observed in supra-aortic SIEs patients. • Capillaroscopic density and minor morphological abnormalities or combined with at least two of the three items in the matrix model showed the probability occurrence of supra-aortic SIEs was 61.2-87.6%.

In vivo functional imaging with SPECT and PET

Nuclear medicine methods permit the visualisation of a variety of metabolic and physiological processes all over the body. Although planar scintigraphy has been found useful for many questions, detailed spatial information about the diseased organ can only be obtained with tomographic methods. Dependent on the radionuclide involved, two different tomographic procedures are available: single photon emission computed tomography (SPECT) and positron emission tomography (PET). The first part of this paper describes shortly the historical development of these methods as well as their technical and methodological basics. To elucidate the large variety of possible applications, an overview of SPECT and PET procedures utilised in research as well as in clinical practice are presented. Furthermore, both methods are compared and their individual advantages are pointed out.

The usefulness of Tc-99m DMSA SPECT and three-dimensional surface rendering in an asymptomatic patient with a single kidney in the pelvis

The diagnostic problems in a clinically asymptomatic patient with a previously unknown ectopic single kidney in the pelvis and the diagnostic utility of three-dimensional surface rendering of Tc-99m DMSA SPECT for delineating ectopic functional renal parenchyma are reported. Inconclusive dynamic planar Tc-99m MAG3 renal scintigraphy was performed with the field of view centered at the upper abdomen. Twenty-four hours later, static planar Tc-99m DMSA scintigraphy 3 hours after injection delineated functional renal parenchyma only in the pelvis but did not reveal the shape of the organ. Three-dimensional surface rendering exposed a single ectopic kidney in the pelvis. This case is the first description of the advantages of three-dimensional surface rendering of Tc-99m SPECT in the diagnosis of an ectopic kidney.

Renal SPECT with Tc-99m DMSA in children with upper urinary tract infections using a triple-headed gamma camera

Renal cortical scintigraphy with Tc-99m DMSA provides an excellent imaging modality for the assessment of cortical damage secondary to upper urinary tract infection (UTI).

METHODS

The authors evaluated 48 children with UTI, 12 of whom had a history of vescico-ureteral reflux (from first of fourth degree), by planar scintigraphy and SPECT using a triple-headed gamma camera equipped with parallel-hole, high-resolution collimators.

RESULTS

SPECT images yielded positive findings in 36 kidneys, whereas planar scans yielded positive findings in 18 kidneys. The total number of lesions detected by SPECT was 51, whereas the number found with the planar technique was 23.

CONCLUSION

This study demonstrates the superiority of SPECT scanning in detecting kidney lesions in children with UTI.

The true clinical significance of renography in nephro-urology

Isotopic renography is a non-invasive technique used routinely by the clinician to provide information about kidney structure and function. Whilst there is no doubt of its value in the accurate measurement of glomerular filtration rate and in the detection of parenchymal abnormalities, its role in the diagnosis of renovascular disease (especially in patients with renal insufficiency), the exclusion of obstruction and the evaluation of the patient with either acute renal failure or renal transplant dysfunction remains unproven. In part, this reflects a failure to standardise protocols and rigorously evaluate diagnostic techniques. Recent developments in ultrasound, computerised X-ray tomography and nuclear magnetic resonance now present the clinician with rival techniques and emphasise the need for the clinical development of isotopic renography.

Qualitative and quantitative evaluation of renal parenchymal damage by 99mTc-DMSA planar and SPECT scintigraphy

The initial 99mTc-DMSA studies carried out over a four year period in 229 patients with various heterogenic causes of lower urinary tract abnormalities were reviewed. Anatomical damage to the renal parenchyma was graded by means of planar and SPECT studies into a six group classification proposed by Monsour et al.: grade 0 (normal), I (equivocal), II (single defect), III (more than 2 defects), IV (contracted or small) and V (no visualization). Parenchymal uptake of 99mTc-DMSA was quantitated from planar images at 2 hours postinjection by a computer assisted gamma camera method. SPECT studies could enhance the pick-up rate for parenchymal uptake defects by a factor of 1.5 in comparison with planar imaging. The incidence of anatomical damage to the renal parenchyma increased with a high radiological grade for VUR, and renal uptake per injection dose of 99mTc-DMSA by the individual kidney significantly decreased in grades III and IV of the anatomical classification. These data revealed that 99mTc-DMSA planar is still useful for evaluating gross structural damage and for quantitative evaluation of the kidney with computer assistance. SPECT scintigraphy is more effective in disclosing anatomical damage to the renal parenchyma than planar, although it needs further discussion as to whether SPECT may increase sensitivity with minimal or no adverse affect on specificity.

A comparative study of evaluating renal scars by 99mTc-DMSA planar and SPECT renal scans, intravenous urography, and ultrasonography

The purpose of this prospective study is to compare 3 types of 99mTc-DMSA renal scan [(a) planar, (b) x-ray type film static SPECT presentation (SPECT-1) and (c) dynamic three-view display of SPECT slices (SPECT-2)], intravenous urography, and ultrasonography in the diagnosis of renal scars. All these studies were performed in 130 pediatric patients, with urinary tract infection (42 patients), vesicoureteral reflux (37), and unilateral or bilateral small kidney(s) (51). The number of renal scars detected was highest with the 99mTc-DMSA renal SPECT-1 scan and next came the 99mTc-DMSA renal SPECT-2 studies. There is a significant difference (p < 0.05) between the ability of planar and SPECT-1 to recognize renal defects. However, SPECT-2 may provide the best stereotactic localization and image quality of all the methods.