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Biomedical subjects

J M Halls

Publications and source records attributed to J M Halls.

At least 37 records · Page 2Linked to original sources

Kock continent ileal urinary reservoir. Anatomy and potential pitfalls of radionuclide imaging.

The Kock continent ileal urinary reservoir (Kock pouch) is a new form of urinary diversion that, due to its advantages over previous techniques of urinary bypass, will probably become widespread in urologic practice. When bone imaging is performed in the presence of the Kock pouch, the unusual configuration of the pouch may obscure or simulate osseous lesions. An understanding of the surgical anatomy as well as the planar and SPECT scintigraphic appearances of the Kock pouch is necessary to avoid errors during interpretation. This series of 51 bone images reports on the variable scintigraphic appearance of the Kock pouch. In addition, the incidence and type of potentially avoidable pitfalls in the interpretation of bone imaging when this form of urinary diversion is used are evaluated.

Aged↗

Hepatobiliary scintigraphy and scintiangiography in abdominal trauma.

Scintiangiography and hepatobiliary scintigraphy were performed in 45 patients with abdominal trauma. There were 18 gunshot wounds, six stab wounds, and 21 blunt injuries. Thirty-one of 45 patients showed abnormalities (69%). There were nine bilomas (4 with leaks), three leaks without biloma, (7 total leaks), five liver hematomas, three liver infarcts, one liver abscess, four renal injuries, one post-traumatic hepatic artery aneurysm, one acute acalculus cholecystitis, and four bowel injuries including one fistula, two obstructions, and one stricture. Two of the renal injuries and the hepatic artery aneurysm were identified only during scintiangiography. Eighteen of 38 gallbladders were not visualized despite normal bowel transit and delayed views to 4 hours (47%). Fourteen of 16 gallbladders were grossly normal at surgery, one had gallstones, and one had post-traumatic acalculus cholecystitis (6%). Hepatobiliary scintiangiography showed unique characteristics of vascular and renal lesions that were not seen on routine images. Sulfur colloid had no advantage over disofenin in evaluating liver injuries in nine cases. A high percentage of nonvisualized gallbladders (47%) were noted in acutely traumatized patients, and caution is recommended in diagnosing acute cholecystitis in the face of trauma.

Abdominal Injuries↗

Cholelithiasis: evaluation with CT.

Computed tomography (CT) is often the first imaging modality used in the diagnosis of patients with suspected abdominal disease. While it is known that early generation CT scanners often detect gallstones, the detection rate of newer equipment is not widely known. Abdominal CT scans of 226 patients who had undergone ultrasonographic (US) studies of the gallbladder were reviewed in a blinded study to determine the accuracy of state-of-the-art CT scanning equipment in the detection of cholelithiasis. Of 110 patients with US or surgical evidence of cholelithiasis, gallstones were demonstrated on CT images of 87 (79.1% sensitivity). Overall accuracy was 89.8%, while specificity was 100%. On CT images stones could appear densely (48.3%) or slightly (11.5%) calcified, as an area with a rim of increased density (21.8%), as an area of soft-tissue density (14.9%), or as an area of low density (3.4%). Stone size, stone density, section incrementation, and the pericholecystic anatomy affected the detection rate. Understanding the spectrum of findings and the other factors involved can optimize success of diagnosis of cholelithiasis on the basis of CT examinations.

Cholecystography↗

Acute cholecystitis: diagnosis with radionuclide angiography.

Radionuclide angiography and cholescintigraphy were performed with a bolus injection of technetium-99m disofenin in 65 patients with suspected acute cholecystitis. Acute cholecystitis was surgically confirmed in 23 of 25 cases in which radionuclide angiographic findings were positive (i.e., showed focal increased flow to the gallbladder region) (positive predictive value, 92%). Sensitivity and specificity of radionuclide angiography for detecting acute cholecystitis were 72% and 94% for cholescintigraphy. Three patients with scintigraphically visible gallbladders (at 45 minutes, 2.4 hours, and 4.5 hours) and positive angiograms had severe acute cholecystitis and abscess. All 20 patients with positive radionuclide angiographic and scintigraphic results had transmural acute cholecystitis. None of the nine patients with acute cholecystitis and false-negative angiograms had abscess or gangrene of the gallbladder. Use of radionuclide angiography may enable the prediction of the severity of acute cholecystitis, as nine of 25 patients with positive findings had either gangrenous cholecystitis or pericholecystic abscess. Positive findings on radionuclide angiograms may preclude the need to obtain delayed (beyond 1 hour) cholescintiscans.

Acute Disease↗

Agenesis of the right lobe of the liver.

In five patients with agenesis of the right lobe of the liver, computed tomography or sonography demonstrated absence of the right lobe with compensatory hypertrophy of other segments. In three patients, the caudate lobe was also absent. The radiologic differential diagnosis includes lobar atrophy due to cirrhosis or hilar cholangiocarcinoma. Nineteen other cases have been reported in the world literature since 1956. This interesting congenital anomaly may be associated with biliary tract disease (12 patients), portal hypertension (seven patients), and other congenital anomalies (four patients), or it may be an incidental finding (five patients).

Adult↗

Amebic liver abscess: MR imaging.

Hepatic magnetic resonance (MR) imaging was performed in 12 patients with 13 amebic liver abscesses. While no specific image or intensity pattern was noted, most lesions were round or oval with smooth, well-defined margins; had decreased signal intensity compared with that of liver parenchyma on T1-weighted images and increased signal intensity on T2-weighted images; and had prominent, often multiple rims of variable signal intensity. Signal homogeneity within the abscess was present more often on T1- than on T2-weighted images. Diaphragmatic disruption was seen in two cases on coronal MR images. An amebic empyema was differentiable from sympathetic pleural effusions by its hyperintensity on both T1- and T2-weighted images. In patients who also underwent computed tomography (CT) or ultrasonography (US), no lesion was missed with any modality, and except for shape, no consistent features were found among images obtained with the different modalities. The data suggest that CT, US, and MR imaging are comparably effective in the detection of amebic abscess.

Evaluation Studies as Topic↗

Cecal volvulus: a complication of colonoscopy.

Colonoscopy is a widely used procedure with low morbidity and mortality. A case of cecal volvulus following colonoscopy is presented. This potentially lethal complication should be considered in patients with persistent abdominal pain following colonoscopy because it is easily diagnosed radiographically and requires emergency surgical intervention.

Cecal Diseases↗

Cholescintigraphy in gallbladder carcinoma.

Findings on cholescintigraphy in gallbladder carcinoma are described in five patients. Four patients presenting with acute cholecystitis had nonvisualization of the gallbladder with normal hepatoenteric transit time. One of these had a large portal mass and two had liver metastasis as additional findings. The fifth patient was jaundiced, and showed absence of bowel activity compatible with total biliary obstruction. Both the clinical and scintigraphic findings in gallbladder carcinoma are difficult to separate from findings in cholelithiasis and cholecystitis.

Adult↗

Hepatobiliary imaging in choledocholithiasis. A comparison with ultrasound.

A retrospective analysis of preoperative biliary imaging and ultrasound in 22 patients with surgically proven choledocholithiasis was performed. Ultrasound detected dilated ducts greater than 7 mm in 11 of 14 jaundiced patients (79%). Hepatobiliary imaging was able to detect either absent or delayed bowel visualization or prominent bile ducts in 13 of 14 jaundiced patients (93%). Of eight nonjaundiced patients, ultrasound showed dilated ducts in three (38%). Hepatobiliary imaging showed either absent bowel activity or prominent ducts in six of eight nonjaundiced patients (75%). Twenty of 22 patients had stones in the gallbladder that were detected by ultrasound, although only one patient had actual visualization of the common duct stone. Hepatobiliary imaging may show abnormalities in choledocholithiasis with normal ultrasound studies.

Adult↗

FM sonography in diffuse liver disease: prospective assessment and blinded analysis.

FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.

Hepatitis↗

Imaging of the Kock continent ileal urinary reservoir.

The Kock continent ileal urinary reservoir (Kock pouch) is a new urinary bypass system that can overcome some of the principal complications associated with other forms of urinary diversion. It is important to understand the anatomy and radiology of this new technique since radiologists play an important role in evaluating the function of the Kock pouch as well as assessing its complications. The authors review the clinical and radiographic findings in 193 patients who had undergone Kock pouch urinary diversion. Patients are evaluated radiographically in the immediate postoperative period and at regular postoperative intervals for as long as 3 years. Routine evaluation consists of Kock pouch cystography followed by intravenous urography. When indicated, computed tomography, ultrasound, and interventional radiologic procedures are used. The normal anatomy as well as the radiographic appearance of the Kock pouch is presented. In addition, the radiographic appearance of pouch complications and their frequency are reviewed.

Adolescent↗

Pheochromocytoma: detection by unenhanced CT.

During a 2 1/2-year period, 10 patients with suspected pheochromocytoma were evaluated by unenhanced computed tomography (CT). Six adrenal masses, one hyperplastic adrenal gland, and two extraadrenal retroperitoneal masses were detected in seven patients; CT of the adrenals and retroperitoneum was normal in three patients. Scintigraphy with iodine-131 metaiodobenzylguanidine (131I-MIBG) was performed in nine of the 10 patients and corroborated the CT findings in all cases. In the three patients with normal CT and 131I-MIBG scintigraphic findings, follow-up assays of serum catecholamines were normal. In six of the seven patients with abnormal CT scans, surgical and pathologic confirmation was obtained; one patient was lost to follow-up after her CT scan. Unenhanced CT is recommended as the initial localizing procedure in patients with suspected pheochromocytoma, thereby avoiding the small but finite risk of hypertensive crisis associated with intravenous injection of urographic contrast medium.

Adrenal Gland Neoplasms↗

Real-time sonography in suspected acute cholecystitis. Prospective evaluation of primary and secondary signs.

Sonographic findings in 497 patients with suspected acute cholecystitis were analyzed prospectively. Combined use of primary and secondary sonographic signs led to excellent positive and negative predictive values. Positive predictive values for stones combined with either a positive sonographic Murphy sign (92.2%) or with gallbladder wall thickening (95.2%) were excellent for acute cholecystitis. Positive predictive value of these signs for patients requiring cholecystectomy was even higher (99.0%). Negative predictive values for combined use of primary and secondary signs to exclude acute cholecystitis were also excellent (95.0% for no stones and negative sonographic Murphy sign). Real-time sonography alone, using both primary and secondary signs, can be definitive in nearly 80% of patients with suspected acute cholecystitis. These patients require no further imaging evaluation. Sonography should be the screening test of choice in acute cholecystitis because it is cost effective, prospectively highly accurate, quick, and better at characterizing and detecting other abdominal lesions than cholescintigraphy. A proposed algorithm is described.

Acute Disease↗