Kevin J. Roche

Interrupted aortic arch: diagnosis with gadolinium-enhanced 3D MRA.

PURPOSE Our goal was to describe the use of gadolinium-enhanced 3D MR angiography (MRA) in the diagnosis of interrupted aortic arch (IAA). METHOD A review of our MR data base from a 1 year period yielded three patients (1 day, 8 days, and 16 years old) with IAA. All were referred for evaluation of aortic arch abnormalities, only one of whom had suspected IAA. Patients were imaged at 1.5 T with a 3D spoiled gradient echo pulse sequence (TR/TE 3.8-8/1.3-2.7 ms) following the administration of intravenous gadolinium chelates. Surgical correlation was available in all cases. RESULTS In the patient with clinically suspected IAA, a previously unsuspected aberrant right subclavian artery was identified that was not seen on preoperative echocardiography. In another patient with a history of previous mediastinal surgery, IAA was diagnosed without concomitant cardiac anomalies, suggesting surgical ligation. In the remaining patient, IAA was detected as well as a patent truncus arteriosus. CONCLUSION Gadolinium-enhanced 3D MRA may provide for a rapid diagnosis of IAA that may not be possible with other noninvasive modalities. The rapid acquisition time enables unstable pediatric patients to spend minimal time in the MR suite.

Adenomyoma Arising in a Meckel Diverticulum: Case Report and Review of the Literature

We report a case of adenomyoma of the small intestine arising in a Meckel diverticulum. The patient was a 22-month-old boy who presented with signs and symptoms of intussusception. At surgery, a Meckel diverticulum was found and removed. On histologic examination, a tumor consisting of dilated cystic glands and smooth muscle bundles was identified. A diagnosis of adenomyoma arising in a Meckel diverticulum was made. A review of the literature showed that only six other pediatric cases of adenomyoma of the small intestine have been reported. The presence of an adenomyoma in a young patient within a Meckel diverticulum favors the view that adenomyomas are a variant of pancreatic heterotopia.

Pediatric hepatic CT: an injection protocol

Objective. To determine an injection protocol for pediatric hepatic CT and to investigate the use of power injection.Materials and methods. Eighty-seven studies were prospectively performed using ioversol (320 mg iodine per cc) at 2 cc/kg. Three techniques were used: helical (1 s/slice); dynamic, non-breath-hold (5.5 s/slice); dynamic, breath-hold (10 s/slice) scans. The liver-scan time for each study was determined. Scan initiation ranged from 25 to 80 s. An injection duration (50–100 seconds) was selected. From the contrast volume (2 cc/kg × kg body wt) and injection duration, the injection rate (cc/s) was calculated for each patient. Each study was grouped by injection rate corrected for body weight (cc/kg/min) into: 1.2–1.5, 1.51–2.0, and 2.01–2.4. The aortic/liver attenuation curves were plotted for each group.Results. Liver-scan time for helical studies was a mean of 26 s, for dynamic, non-breath-hold studies 75 s, dynamic breath-hold scans were 154 s. Injection rates of 1.2–1.5 cc/kg/min produced a scanning interval of 165 s. Injection rates of 1.51–2.0 cc/kg/min produced a scanning interval of 120 s. Injection rates of 2.01–2.4 cc/kg/min produced a scanning interval of 90 s. There was no increase in hepatic attenuation for the injection rates 2.01–2.4 cc/kg/min compared with 1.51–2.0 cc/kg/min. There was one complication related to injection through a central line.Conclusions. An injection protocol was determined for helical studies with injection rates of 1.7–2.0 cc/kg/min with initiation at 60 s; for dynamic, non-breath-hold studies with injection rates of 1.5–1.7 cc/kg/min with initiation at 50 s; and for dynamic breath-hold studies with injection rates of 1.2–1.5 cc/kg/min with initiation at 45 s. Power injection was used safely in our population.

MR findings in Shone's complex of left heart obstructive lesions.

Background. Shones complex is a series of four obstructive or potentially obstructive left-sided cardiac lesions (supravalvular mitral ring, parachute deformity of the mitral value, subaortic stenosis, and coarctation of the aorta). Both the complete form (all four lesions) and incomplete forms (less than four lesions) have been described. Objective. To determine which abnormalities of Shones complex could be characterized by MR. Materials and methods. MR examinations in three patients (one complete, two incomplete) were retrospectively reviewed. Results. A supravalvular mitral ring, found at surgery in one patient, was not identified. Regurgitant and stenotic flow across the mitral valve, abnormal motion of the valve leaflets and abnormalities of the papillary muscles were identified. Individual chordal attachments were difficult to resolve. Narrowing in the subaortic region and abnormal flow from the subaortic region through the valve plane were demonstrated. A discrete subaortic diaphragm in one patient was not resolved. Both focal and diffuse types of coarctation of the aorta were well characterized. Conclusion. MR imaging is suited to evaluation of patients with Shones complex. Individual chordal attachments and thin diaphragms of the mitral and aortic valves were difficult to resolve.

Resonance imaging of a ruptured aneurysm of the sinus of Valsalva

Ruptured aneurysm of an aortic sinus of Valsalva is a rare cause of left-to-right shunting. We show how resonance imaging can be used to make the diagnosis. This technique can successfully characterize the shunt as well as determine the presence of associated anomalies, such as ventricular septation and aortic regurgitation. It may be the only study required prior to therapeutic intervention.