Suzanne T. Mastin

Age-related radiological imaging in children with acute pyelonephritis

Abstract. Accurate diagnosis of acute pyelonephritis (APN) using clinical and laboratory parameters is often difficult in children. The aims of this retrospective study were twofold. Firstly, to correlate the clinical and laboratory manifestations of APN with the results of the dimercaptosuccinic acid (DMSA) renal scan in different age groups. Secondly, to compare the DMSA renal scan, renal ultrasonography (RUS), and voiding cystourethrography (VCUG) in patients with clinical APN. The DMSA renal scan was utilized as the gold standard for renal involvement. We determined the sensitivity of these tests in febrile urinary tract infections (UTI) in three age groups: group I less than 2 years; group II 2–8 years; group III older than 8 years. During the period January 1992 through December 1998, 222 children presented with a febrile UTI. All patients had a DMSA renal scan, 208 had contrast VCUG, and 163 had RUS. The clinical and laboratory manifestation of pyelonephritis correlated better with a positive DMSA renal scan in the older children than in the younger children; 85% of the DMSA renal scans were positive in group III; 69% in group II; 48% in group I (P<0.001). Vesicoureteral reflux detected by contrast VCUG was more prevalent in the younger age groups. Although high grades of reflux (grade IV–V) correlated better with a positive DMSA renal scan, it did not reach a level of statistical significance (P>0.05). RUS did not correlate with a positive DMSA renal scan in any age group.

Comparative value of thallium and glucose SPECT imaging in childhood brain tumors

Thallium-201 chloride (201Tl) single-photon emission computed tomography (SPECT) detects a high percentage of histologically and anatomically diverse pediatric brain tumors. Thallium-201 chloride SPECT and F-18 fluoro-deoxy-glucose (18F-FDG) positron emission tomography (PET) are the most commonly used radionuclide techniques in neuro-oncology. Having developed a methodology to image 18F-FDG with SPECT, the authors performed SPECT scans coupled with magnetic resonance imaging to assess the comparative sensitivity of 201Tl and 18F-FDG in 19 children with brain tumors. Tumors were detected using 201Tl SPECT in 14 of 19 patients. Five of five postoperative residual tumors were detected by 201Tl SPECT, and six of seven after irradiation recurrences were detected. F-18 fluoro-deoxy-glucose SPECT detected tumors in only three of 19 patients, all of whom had abnormal 201Tl studies (all three after therapy recurrences). Thallium-201 chloride SPECT could be interpreted in 18 of 19 patients without magnetic resonance imaging confirmation, but none of the 19 18F-FDG SPECT studies could be interpreted without magnetic resonance imaging. Thallium-201 chloride SPECT is more sensitive than 18F-FDG SPECT in the detection of primary or recurrent childhood brain tumors. The failure of 18F-FDG SPECT in follow-up after therapy is primarily a problem of limited fluoro-deoxy-glucose uptake, not spatial resolution. Thallium-201 chloride SPECT is a promising imaging modality in neuro-oncology.

Tc-99m DMSA SPECT imaging in patients with acute symptoms or history of UTI: comparison with ultrasonography

Although planar cortical scintigraphy has been demonstrated to be a sensitive test for the detection of renal infection and scarring, one criticism has been radiation dose to the renal cortex. Recent studies of cortical SPECT suggest a sensitivity for detection of lesions equal to, or greater than, that of planar scans. The authors prospectively performed SPECT scans on 36 patients referred for recurrent urinary tract infection (UTI) (11 of 36), or recent onset of symptoms of UTI (25/36) after 30–40% of the standard 130 MBq (3.5 mCI) adult dose of Tc-99m DMSA was administered. Comparison was made with ultrasonography (US) performed at, or near, the same time. Of 67 kidneys evaluated, 34 (51%) demonstrated focal cortical loss on Tc-99m DMSA scintigraphy, 1 kidney was small in size, and 32 kidneys were normal. Abnormalities were noticed in only 13 (19%) of kidneys on US. Previously, US has been the primary imaging modality in the evaluation of the young patient with UTI. Triple-headed Tc-99m DMSA SPECT scintigraphy is a more sensitive, low-dose (12 mGy, 1.2 r) method of detecting renal cortical abnormalities. As such, it is a more appropriate test for identifying sites of cortical infection and scarring and for following patients on prophylactic therapy for evidence of asymptomatic breakthrough infections.

Dynamic simultaneous anterior and posterior imaging of transplant and native renal function using dual-headed gamma camera.

The authors describe the nonvisualization of a renal transplant on DTPA scan with late visualization of activity within the bladder in a 27-year-old patient with diabetes. Origin of bladder activity was later clarified by dynamic anterior and posterior imaging using MAG 3 and an extra large field-of-view, dual-headed gamma camera.

Coronary Cardiac Fistula Evaluation by Cardiac CTA for Management

We present the case of a 5-year-old otherwise healthy female referred to our clinic for evaluation of a continuous cardiac murmur heard at the left upper sternal border. A differential diagnosis of patent ductus arteriosus versus coronary cardiac fistula versus arteriovenous fistula was considered based on the physical examination. Initial transthoracic echocardiogram demonstrated a large right coronary artery (RCA) to right ventricle (RV) fistula with a very dilated (7 mm) proximal RCA (Supplementary Video S1). There was associated moderate right heart dilation. On further discussion with our pediatric cardiothoracic surgeon and interventional cardiologist, initial consensus was to first obtain a prospectively gated pediatric cardiac computed tomographic angiography (CTA) to better delineate morphology of the coronary cardiac fistula especially with respect to elucidating the proximity of the distal communication of the coronary cardiac fistula to the posterior descending artery prior to establishing surgical versus interventional candidacy. The CTA confirmed the anatomy of the RCA to RV fistula and demonstrated diffuse ectasia of the RCA (7.2 mm; z score of 14.5). Maximum intensity projection with vessel tracking software clearly delineated the fistulous connection at the base of RV (Figure 1A). Three-dimensional reformation from the CTA demonstrated the dilated RCA and its fistulous connection to the RV (Figure 1B, Supplementary Video S2). The RCA was massively dilated secondary to the increased flow from the fistula (Figure 1C, Supplementary Video S3). The CTA findings were determined to be conducive for device closure of the coronary cardiac fistula and the patient successfully underwent percutaneous catheter-directed coil occlusion of the fistula (Figure 1D, Supplementary Videos S4-S6). She remains asymptomatic on anticoagulation for ongoing dilation of her RCA. Our case highlights the utility of cardiac CTA in delineating aberrant pediatric coronary anatomy, allowing for assessment of operative candidacy and treatment planning (surgical vs interventional) especially as it pertains to delineating the baseline morphology but also minimizing the risk of potential device-related complications such as compression of adjacent structures or embolization. Cardiac CTA clearly delineated the anatomy of the coronary cardiac fistula while complementing the functional assessment provided by echocardiogram.

Case of double-outlet right ventricle after repair with pulmonary arteriovenous malformations using cardiac CT

We present a case where cardiac CT clearly defines the complex anatomy of a 22 year old man with double outlet right ventricle who is status bilateral bidirectional Glenn and Fontan conduit. This case also shows the association of pulmonary arteriovenous malformations with Fontan and Glenn procedures.